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[0001] This application claims the benefit of U.S. Provisional Application No. 60/892,916, filed Mar. 5, 2007, and U.S. Provisional Application No. 60/923,117, filed Apr. 12, 2007, whose contents are hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention relates generally to the field of pharmacogenomics. More specifically, the invention relates to methods and procedures to determine drug sensitivity and insensitivity in patients, which allows the identification of individualized genetic profiles which will aid in treating diseases and disorders including cancer. The invention also relates to methods for predicting the likelihood a mammal will respond therapeutically to a method of treating cancer.
BACKGROUND OF THE INVENTION
[0003] Cancer is a disease with extensive histoclinical heterogeneity. Although conventional histological and clinical features have been correlated to prognosis, the same apparent prognostic type of tumors varies widely in its responsiveness to therapy and consequent survival of the patient.
[0004] New prognostic and predictive markers, which would facilitate an individualization of therapy for each patient, are needed to accurately predict patient response to treatments, such as small molecule or biological molecule drugs, in the clinic. The problem may be solved by the identification of new parameters that could better predict the patient's sensitivity to treatment. The classification of patient samples is a crucial aspect of cancer diagnosis and treatment. The association of a patient's response to a treatment with molecular and genetic markers can open up new opportunities for treatment development in non-responding patients, or distinguish a treatment's indication among other treatment choices because of higher confidence in the efficacy. Further, the pre-selection of patients who are likely to respond well to a medicine, drug, or combination therapy may reduce the number of patients needed in a clinical study or accelerate the time needed to complete a clinical development program (Cockett et al., Current Opinion in Biotechnology, 11:602-609 (2000)).
[0005] The ability to predict drug sensitivity in patients is particularly challenging because drug responses reflect not only properties intrinsic to the target cells, but also a host's metabolic properties. Efforts to use genetic information to predict drug sensitivity have primarily focused on individual genes that have broad effects, such as the multidrug resistance genes, mdr1 and mrp1 (Sonneveld, J. Intern. Med., 247:521-534 (2000)).
[0006] The development of microarray technologies for large scale characterization of gene mRNA expression pattern has made it possible to systematically search for molecular markers and to categorize cancers into distinct subgroups not evident by traditional histopathological methods (Khan et al., Cancer Res., 58:5009-5013 (1998); Alizadeh et al., Nature, 403:503-511 (2000); Bittner et al., Nature, 406:536-540 (2000); Khan et al., Nature Medicine, 7(6):673-679 (2001); and Golub et al., Science, 286:531-537 (1999); Alon et al., P. N. A. S. USA, 96:6745-6750 (1999)). Such technologies and molecular tools have made it possible to monitor the expression level of a large number of transcripts within a cell population at any given time (see, e.g., Schena et al., Science, 270:467-470 (1995); Lockhart et al., Nature Biotechnology, 14:1675-1680 (1996); Blanchard et al., Nature Biotechnology, 14:1649 (1996); U.S. Pat. No. 5,569,588).
[0007] Recent studies demonstrate that gene expression information generated by microarray analysis of human tumors can predict clinical outcome (van't Veer et al., Nature, 415:530-536 (2002); Sorlie et al., P. N. A. S. USA, 98:10869-10874 (2001); M. Shipp et al., Nature Medicine, 8(1):68-74 (2002): Glinsky et al., The Journal of Clin. Invest., 113(6):913-923 (2004)). These findings bring hope that cancer treatment will be vastly improved by better predicting the response of individual tumors to therapy.
[0008] The vertebrate immune system requires multiple signals to achieve optimal immune activation (see, e.g., Janeway, Cold Spring Harbor Symp. Quant. Biol. 1989; 54:1-14; Paul William E., ed. Raven Press, N.Y., Fundamental Immunology, 4th edition (1998), particularly chapters 12 and 13, pages 411 to 478). Interactions between T lymphocytes (T cells) and antigen presenting cells (APC) are essential to the immune response. Levels of many cohesive molecules found on T cells and APC's increase during an immune response (Springer et al., A. Rev. Immunol. 1987; 5:223-252; Shaw and Shimuzu, Current Opinion in Immunology, 1988 Eds. Kindt and Long, 1:92-97; and Hemler, Immunology Today 1988; 9:109-113). Increased levels of these molecules may help explain why activated APC's are more effective at stimulating antigen-specific T cell proliferation than are resting APC's (Kaiuchi et al., J. Immunol. 1983; 131:109-114; Kreiger et al., J. Immunol. 1985; 135:2937-2945; McKenzie, J. Immunol. 1988; 141:2907-2911; and Hawrylowicz and Unanue, J. Immunol. 1988; 141:4083-4088).
[0009] T cell immune response is a complex process that involves cell-cell interactions (Springer et al., A. Rev. Immunol. 1987; 5:223-252), particularly between T and accessory cells such as APC's, and production of soluble immune mediators (cytokines or lymphokines) (Dinarello, New Engl. J. Med 1987; 317:940-945; Sallusto, J. Exp. Med. 1997; 179:1109-1118). This response is regulated by several T-cell surface receptors, including the T-cell receptor complex (Weiss, Aim. Rev. Immunol. 1986; 4:593-619) and other “accessory” surface molecules (Allison, Curr. Opin. Immunol. 1994; 6:414-419; Springer, 1987, supra). Many of these accessory molecules are naturally occurring cell surface differentiation (CD) antigens defined by the reactivity of monoclonal antibodies on the surface of cells (McMichael, Ed., Leukocyte Typing III, Oxford Univ. Press, Oxford, N.Y., 1987).
[0010] CD28 antigen, a homodimeric glycoprotein of the immunoglobulin superfamily (Aruffo and Seed, Proc. Natl. Acad. Sci. 1987; 84:8573-8577), is an accessory molecule found on most mature human T cells (Damle et al., J. Immunol. 1983; 131:2296-2300). Current evidence suggests that this molecule functions in an alternative T cell activation pathway distinct from that initiated by the T-cell receptor complex (June et al., Mol. Cell. Biol. 1987; 7:4472-4481). Monoclonal antibodies (MAbs) reactive with CD28 antigen can augment T cell responses initiated by various polyclonal stimuli (reviewed by June et al., supra). These stimulatory effects may result from MAb-induced cytokine production (Thompson et al., Proc. Natl. Acad. Sci. 1989; 86:1333-1337; and Lindsten et al., Science 1989; 244:339-343) as a consequence of increased mRNA stabilization (Lindsten et al., 1989, supra).
[0011] CTLA-4 is a negative regulator of CD28′ dependent T cell activation, and acts as an inhibitory checkpoint for the adaptive immune response. Various preclinical studies have shown that CTLA-4 blockade by monoclonal antibodies enhances the host immune response against immunogenic tumors, and can even reject established tumors. Currently, ipilimumab (MDX-010) and CP-675206, both fully human anti-human CTLA-4 monoclonal antibodies (mAbs), are under clinical development to treat various types of solid tumors.
[0012] CTLA-4 (cytotoxic T lymphocycte-associated antigen-4) is accepted as opposing CD28 activity and dampening T cell activation (Krummel, J. Exp. Med. 1995; 182:459-465; Krummel et al., Int'l Immunol. 1996; 8:519-523; Chambers et al., Immunity. 1997; 7:885-895). CTLA-4 deficient mice suffer from massive lymphoproliferation (Chambers et al., supra). It has been reported that CTLA-4 blockade augments T cell responses in vitro (Walunas et al., Immunity. 1994; 1:405-413) and in vivo (Kearney, J. Immunol. 1995; 155:1032-1036), exacerbates antitumor immunity (Leach, Science 1996; 271:1734-1736), and enhances an induced autoimmune disease (Luhder, J. Exp. Med. 1998; 187:427-432). It has also been reported that CTLA-4 has an alternative or additional impact on the initial character of the T cell immune response (Chambers, Curr. Opin. Immunol. 1997; 9:396-404; Bluestone, J. Immunol. 1997; 158:1989-1993; Thompson, Immunity 1997; 7:445-450). This is consistent with the observation that some autoimmune patients have autoantibodies to CTLA-4. It is possible that CTLA-4 blocking autoantibodies play a pathogenic role in these patients (Matsui, J. Immunol. 1999; 162:4328-4335).
[0013] Non-human CTLA-4 antibodies have been used in the various studies discussed above. Furthermore, human antibodies against human CTLA-4 have been described as immunostimulation modulators in a number of disease conditions, such as treating or preventing viral and bacterial infection and for treating cancer (e.g., PCT Publication WO 01/14424 and PCT Publication WO 00/37504). U.S. Pat. No. 5,855,887 discloses a method of increasing the response of a mammalian T cell to antigenic stimulation by combining a T cell with a CTLA-4 blocking agent. U.S. Pat. No. 5,811,097 discloses a method of decreasing the growth of non-T cell tumors by administering a CTLA-4 blocking agent. U.S. Pat. No. 6,984,720 and U.S. Patent Publication No. 2002/0086014 disclose human CTLA-4 antibodies. Each of these patents and applications is hereby incorporated by reference.
[0014] Needed are new and alternative methods and procedures to determine drug sensitivity in patients to allow the development of individualized genetic profiles which are necessary to treat diseases and disorders based on patient response at a molecular level.
SUMMARY OF THE INVENTION
[0015] The invention provides methods and procedures for determining patient sensitivity to one or more CTLA-4 antagonists. The invention also provides methods of determining or predicting whether an individual requiring therapy for a disease state such as cancer will or will not respond to treatment, prior to administration of the treatment, wherein the treatment comprises administration of one or more CTLA-4 antagonists. The one or more CTLA-4 antagonists are compounds that can be selected from, for example, one or more small molecule CTLA-4 inhibitors or one or more CTLA-4 binding monoclonal antibodies.
[0016] In one aspect, the invention provides a method for predicting the likelihood a mammal will respond therapeutically to a method of treating cancer comprising administering an CTLA-4 antagonist, wherein the method comprises: (a) measuring in the mammal the level of at least one biomarker; (b) exposing a biological sample from the mammal to the CTLA-4 antagonist; (c) following the exposing of step (b), measuring in the biological sample the level of the at least one biomarker, wherein an increase in the level of the at least one biomarker measured in step (c) compared to the level of the at least one biomarker measured in step (a) indicates an increased likelihood that the mammal will respond therapeutically to the method of treating cancer.
[0017] In another aspect, the invention provides a method for predicting the likelihood a mammal will respond therapeutically to a method of treating cancer comprising administering an CTLA-4 antagonist, wherein the method comprises: (a) measuring in the mammal the level of at least one biomarker selected from the biomarkers of Table 1 and Table 3; (b) exposing a biological sample from said mammal to the CTLA-4 antagonist; (c) following the exposing of step (b), measuring in said biological sample the level of the at least one biomarker, wherein an increase in the level of the at least one biomarker measured in step (c) compared to the level of the at least one biomarker measured in step (a), indicates an increased likelihood that the mammal will respond therapeutically to said method of treating cancer when said at least one biomarker is from Table 1, and indicates an increased likelihood that the mammal will not respond therapeutically to said method of treating cancer when said at least one biomarker is from Table 3.
[0018] The biological sample can comprise, for example, at least one of whole fresh blood, peripheral blood mononuclear cells, frozen whole blood, fresh plasma, frozen plasma, urine, saliva, skin, hair follicle, bone marrow, or tumor tissue. In one aspect, the biological sample is tumor tissue. In another aspect, the biological sample can be, for example, a tissue sample comprising cancer cells and the tissue is fixed, paraffin-embedded, fresh, or frozen.
[0019] A difference in the level of the biomarker that is sufficient to predict the likelihood that the mammal will or will not respond therapeutically to the method of treating cancer can be readily determined by one of skill in the art using known techniques. The increase or decrease in the level of the biomarker can be correlated to determine whether the difference is sufficient to predict the likelihood that a mammal will respond therapeutically. The difference in the level of the biomarker that is sufficient can, in one aspect, be predetermined prior to predicting the likelihood that the mammal will respond therapeutically to the treatment. In one aspect, the difference in the level of the biomarker is a difference in the mRNA level (measured, for example, by RT-PCR or a microarray), such as at least a two-fold difference, at least a three-fold difference, or at least a four-fold difference in the level of expression. In another aspect, the difference in the level of the biomarker is determined by IHC. In another aspect, the difference in the level of the biomarker refers to a p-value of <0.05 in Anova (t test) analysis. In yet another aspect, the difference is determined in an ELISA assay.
[0020] As used herein, respond therapeutically refers to the alleviation or abrogation of the cancer. This means that the life expectancy of an individual affected with the cancer will be increased or that one or more of the symptoms of the cancer will be reduced or ameliorated. The term encompasses a reduction in cancerous cell growth or tumor volume. Whether a mammal responds therapeutically can be measured by many methods well known in the art, such as PET imaging.
[0021] The mammal can be, for example, a human, rat, mouse, dog, rabbit, pig sheep, cow, horse, cat, primate, or monkey.
[0022] The method of the invention can be, for example, an in vitro method wherein the step of measuring in the mammal the level of at least one biomarker comprises taking a biological sample from the mammal and then measuring the level of the biomarker(s) in the biological sample. In one aspect, the biological sample is tumor tissue. In another aspect, the biological sample can comprise, for example, at least one of serum, whole fresh blood, peripheral blood mononuclear cells, frozen whole blood, fresh plasma, frozen plasma, urine, saliva, skin, hair follicle, bone marrow, or tumor tissue.
[0023] The level of the at least one biomarker can be, for example, the level of protein and/or mRNA transcript of the biomarker. The level of the biomarker can be determined, for example, by RT-PCR or another PCR-based method, immunohistochemistry, proteomics techniques, or any other methods known in the art, or their combination.
[0024] In another aspect, the invention provides a method for identifying a mammal that will respond therapeutically to a method of treating cancer comprising administering of an CTLA-4 antagonist, wherein the method comprises: (a) measuring in the mammal the level of at least one biomarker; (b) exposing a biological sample from the mammal to the CTLA-4 antagonist; (c) following the exposing in step (b), measuring in said biological sample the level of the at least one biomarker, wherein a difference in the level of the at least one biomarker measured in step (c) compared to the level of the at least one biomarker measured in step (a) indicates that the mammal will respond therapeutically to the said method of treating cancer.
[0025] In another aspect, the invention provides a method for identifying a mammal that will respond therapeutically to a method of treating cancer comprising administering an CTLA-4 antagonist, wherein the method comprises: (a) exposing a biological sample from the mammal to the CTLA-4 antagonist; (b) following the exposing of step (a), measuring in said biological sample the level of at least one biomarker, wherein a difference in the level of the at least one biomarker measured in step (b), compared to the level of the at least one biomarker in a mammal that has not been exposed to said CTLA-4 antagonist, indicates that the mammal will respond therapeutically to said method of treating cancer.
[0026] In yet another aspect, the invention provides a method for testing or predicting whether a mammal will respond therapeutically to a method of treating cancer comprising administering an CTLA-4 antagonist, wherein the method comprises: (a) measuring in the mammal the level of at least one biomarker; (b) exposing the mammal to the CTLA-4 antagonist; (c) following the exposing of step (b), measuring in the mammal the level of the at least one biomarker, wherein a difference in the level of the at least one biomarker measured in step (c) compared to the level of the at least one biomarker measured in step (a) indicates that the mammal will respond therapeutically to said method of treating cancer.
[0027] In another aspect, the invention provides a method for determining whether a compound inhibits CTLA-4 activity in a mammal, comprising: (a) exposing the mammal to the compound; and (b) following the exposing of step (a), measuring in the mammal the level of at least one biomarker, wherein a difference in the level of said biomarker measured in step (b), compared to the level of the biomarker in a mammal that has not been exposed to said compound, indicates that the compound inhibits CTLA-4 activity in the mammal.
[0028] In yet another aspect, the invention provides a method for determining whether a mammal has been exposed to a compound that inhibits CTLA-4 activity, comprising (a) exposing the mammal to the compound; and (b) following the exposing of step (a), measuring in the mammal the level of at least one biomarker, wherein a difference in the level of said biomarker measured in step (b), compared to the level of the biomarker in a mammal that has not been exposed to said compound, indicates that the mammal has been exposed to a compound that inhibits CTLA-4 activity.
[0029] In another aspect, the invention provides a method for determining whether a mammal is responding to a compound that inhibits CTLA-4 activity, comprising (a) exposing the mammal to the compound; and (b) following the exposing of step (a), measuring in the mammal the level of at least one biomarker, wherein a difference in the level of the at least one biomarker measured in step (b), compared to the level of the at least one biomarker in a mammal that has not been exposed to said compound, indicates that the mammal is responding to the compound that inhibits CTLA-4 activity.
[0030] As used herein, “responding” encompasses responding by way of a biological and cellular response, as well as a clinical response (such as improved symptoms, a therapeutic effect, or an adverse event), in a mammal.
[0031] The invention also provides an isolated biomarker. The biomarkers of the invention comprise sequences selected from the nucleotide and amino acid sequences, as well as fragments and variants thereof.
[0032] The invention also provides a biomarker set comprising two or more biomarkers.
[0033] The invention also provides kits for determining or predicting whether a patient would be susceptible to a treatment that comprises one or more CTLA-4 antagonists. The patient may have a cancer or tumor.
[0034] In one aspect, the kit comprises a suitable container that comprises one or more specialized microarrays of the invention, one or more CTLA-4 antagonists for use in testing cells from patient tissue specimens or patient samples, and instructions for use. The kit may further comprise reagents or materials for monitoring the expression of a biomarker set at the level of mRNA or protein.
[0035] In another aspect, the invention provides a kit comprising two or more biomarkers.
[0036] In yet another aspect, the invention provides a kit comprising at least one of an antibody and a nucleic acid for detecting the presence of at least one of the biomarkers. In one aspect, the kit further comprises instructions for determining whether or not a mammal will respond therapeutically to a method of treating cancer comprising administering a compound that inhibits CTLA-4 activity. In another aspect, the instructions comprise the steps of (a) measuring in the mammal the level of at least one biomarker, (b) exposing the mammal to the compound, (c) following the exposing of step (b), measuring in the mammal the level of the at least one biomarker, wherein a difference in the level of the at least one biomarker measured in step (c) compared to the level of the at least one biomarker measured in step (a) indicates that the mammal will respond therapeutically to said method of treating cancer.
[0037] The invention also provides screening assays for determining if a patient will be susceptible to treatment with one or more CTLA-4 antagonists.
[0038] The invention also provides a method of monitoring the treatment of a patient having a disease, wherein said disease is treated by a method comprising administering one or more CTLA-4 antagonists.
[0039] The invention also provides individualized genetic profiles which are necessary to treat diseases and disorders based on patient response at a molecular level.
[0040] The invention also provides specialized microarrays, e.g., oligonucleotide microarrays or cDNA microarrays, comprising one or more biomarkers having expression profiles that correlate with sensitivity to one or more CTLA-4 antagonists.
[0041] The invention also provides antibodies, including polyclonal or monoclonal, directed against one or more biomarkers of the invention.
[0042] The invention will be better understood upon a reading of the detailed description of the invention when considered in connection with any accompanying figures.
BRIEF DESCRIPTION OF THE FIGURES
[0043] FIG. 1 illustrates the results obtained of the anti-tumor activity of UC10 in the Sa1N tumor model.
[0044] FIG. 2 illustrates the results obtained from immunohistochemistry staining.
[0045] FIG. 3 ( FIGS. 3A and 3B ) illustrates the results obtained from expansion of T cells with an effector/memory phenotype following UC treatment.
[0046] FIG. 4 illustrates the results obtained from qPCR analysis of tumor RNA
[0047] FIG. 5 illustrates the results obtained from qPCR analysis of peripheral blood RNA.
[0048] FIG. 6 illustrates the results obtained from induction of T cell receptor, immunoglobulin, and class II MHC genes.
[0049] FIG. 7 illustrates the results obtained showing a lack of anti-tumor activity of UC10 in the EMT6 tumor model.
[0050] FIG. 8 illustrates the results obtained from qPCR analysis of tumor RNA.
[0051] FIG. 9 illustrates the results obtained from qPCR analysis of peripheral blood RNA.
[0052] FIG. 10 illustrates the results obtained from measuring the time course of Ym1 and arginase 1 gene expression in the blood.
DETAILED DESCRIPTION OF THE INVENTION
[0053] As used herein, the terms “cytotoxic T lymphocyte-associated antigen-4,” “CTLA-4,” “CTLA4,” “CTLA-4 antigen” and “CD152” (see, e.g., Murata, Am. J. Pathol. 1999; 155:453-460) are used interchangeably, and include variants, isoforms, species homologs of human CTLA-4, and analogs having at least one common epitope with CTLA-4 (see, e.g., Balzano (1992) Int. J. Cancer Suppl. 7:28-32). CTLA-4's complete sequence is found in GenBank Accession No. L15006.
[0054] The human monoclonal antibody MDX-010 (Medarex, Inc.) in clinical development corresponds to monoclonal antibody 10D1, which is disclosed in U.S. Patent Publication No. 20050201994 and PCT Publication No. WO 01/14424. MDX-010 has been administered as single or multiple doses, alone or in combination with a vaccine, chemotherapy, or interleukin-2 to greater than 500 patients diagnosed with metastatic melanoma, prostate cancer, lymphoma, renal cell cancer, breast cancer, ovarian cancer, and HIV.
[0055] Other anti-CTLA-4 antibodies that can be used in a method of the present invention include, for example, those disclosed in: WO 98/42752; WO 00/37504; U.S. Pat. No. 6,207,156; Hurwitz et al., PNAS 1998; 95(17):10067-10071; Camacho et al., J Clin Oncology 2004:22(145):abstract no. 2505 (antibody CP-675206); and Mokyr, et al., Cancer Research 1998; 58:5301-5304.
[0056] In this study, the effect of anti-CTLA-4 treatment on various biomarkers was characterized in mouse tumor models with the goal to obtain candidate biomarkers useful in monitoring the biological effects of this treatment in the clinical setting. Two mouse tumor models, Sa1N (fibrosarcoma, ALT mouse strain) and EMT-6 (mammary carcinoma, Balb/c mouse strain), were used in these studies. The anti-CTLA-4 treatment was highly efficacious against Sa1N tumors, producing complete regressions in most of the treated mice. However, it showed no inhibitory effect on the growth of EMT-6 tumors. Tumor and blood samples from SA1N and EMT-6-bearing mice treated with anti-CTLA-4 antibody or control vehicle were collected at various timepoints. Several selected markers were analyzed by immunohistochemistry (IHC) (tumor only) or RT-PCR (tumor and blood). A significant increase of CD4+ and CD8+ T cells were detected in SA1N tumors (sensitive model) upon treatment but not in EMT-6 tumors (resistant model). Gene expression analysis corroborated the IHC result by showing the induction of various immune response related genes including Cd3d, Cd4, Cd8b1, interferon-γ, perforin 1, and granzyme B in Sa1N tumor, but not in EMT6. These gene expression changes in the tumor tissue reflected the anti-tumor immune reaction induced by this treatment. In the peripheral blood, anti-CTLA-4 treatment in Sa1N-bearing mice also induced IFN-γ, perforin 1, and granzyme B genes, indicating the systemic elevation of Th1 and cytotoxic immune responses. However the same treatment failed to raise the levels of these genes in the EMT6 model blood, and instead it induced the genes related to the alternative activation of macrophages, such as Chi313 (Ym1) and Retnla (Fizz1). Such changes of the gene expression patterns in the peripheral blood reflect different types of immune response induced by this treatment, and may provide useful biomarkers to monitor the action of anti-CTLA4 treatment in the clinical setting.
[0057] The invention provides biomarkers that correlate with CTLA-4 antagonist sensitivity or resistance. These biomarkers can be employed for predicting response to one or more CTLA-4 antagonists. The biomarkers of the invention include polynucleotide and polypeptide sequences.
[0058] The biomarkers have expression levels in cells that may be dependent on the activity of the CTLA-4 signal transduction pathway, and that are also highly correlated with CTLA-4 antagonist sensitivity exhibited by the cells. Biomarkers serve as useful molecular tools for predicting the likelihood of a response to CTLA-4 antagonists, preferably biological molecules, small molecules, and the like that affect CTLA-4 kinase activity via direct or indirect inhibition or antagonism of CTLA-4 kinase function or activity.
Biomarkers and Biomarker Sets
[0059] The invention includes individual biomarkers and biomarker sets having both diagnostic and prognostic value in disease areas in which signaling through CTLA-4 or the CTLA-4 pathway is of importance, e.g., in cancers or tumors, in immunological disorders, conditions or dysfunctions, or in disease states in which cell signaling and/or cellular proliferation controls are abnormal or aberrant. The biomarker sets comprise a plurality of biomarkers that highly correlate with sensitivity to one or more CTLA-4 antagonists.
[0060] The biomarkers and biomarker sets of the invention enable one to predict or reasonably foretell the likely effect of one or more CTLA-4 antagonists in different biological systems or for cellular responses. The biomarkers and biomarker sets can be used in in vitro assays of CTLA-4 antagonist response by test cells to predict in vivo outcome. In accordance with the invention, the various biomarkers and biomarker sets described herein, or the combination of these biomarker sets with other biomarkers or markers, can be used, for example, to predict how patients with cancer might respond to therapeutic intervention with one or more CTLA-4 antagonists.
[0061] A biomarker and biomarker set of cellular gene expression patterns correlating with sensitivity of cells following exposure of the cells to one or more CTLA-4 antagonists provides a useful tool for screening one or more tumor samples before treatment with the CTLA-4 antagonist. The screening allows a prediction of cells of a tumor sample exposed to one or more CTLA-4 antagonists, based on the expression results of the biomarker and biomarker set, as to whether or not the tumor, and hence a patient harboring the tumor, will or will not respond to treatment with the CTLA-4 antagonist.
[0062] The biomarker or biomarker set can also be used as described herein for monitoring the progress of disease treatment or therapy in those patients undergoing treatment for a disease involving an CTLA-4 antagonist.
[0063] The biomarkers also serve as targets for the development of therapies for disease treatment. Such targets may be particularly applicable to treatment of colorectal cancer. Indeed, because these biomarkers are differentially expressed in sensitive cells, their expression patterns are correlated with relative intrinsic sensitivity of cells to treatment with CTLA-4 antagonists.
[0064] The level of biomarker protein and/or mRNA can be determined using methods well known to those skilled in the art. For example, quantification of protein can be carried out using methods such as ELISA, 2-dimensional SDS PAGE, Western blot, immunopreciptation, immunohistochemistry, fluorescence activated cell sorting (FACS), or flow cytometry. Quantification of mRNA can be carried out using methods such as PCR, array hybridization, Northern blot, in-situ hybridization, dot-blot, Taqman, or RNAse protection assay.
Microarrays
[0065] The invention also includes specialized microarrays, e.g., oligonucleotide microarrays or cDNA microarrays, comprising one or more biomarkers, showing expression profiles that correlate with sensitivity to one or more CTLA-4 antagonists. Such microarrays can be employed in in vitro assays for assessing the expression level of the biomarkers in the test cells from tumor biopsies, and determining whether these test cells are likely to be sensitive to CTLA-4 antagonists. For example, a specialized microarray can be prepared using all the biomarkers, or subsets thereof, as described herein. Cells from a tissue or organ biopsy can be isolated and exposed to one or more of the CTLA-4 antagonists. In one aspect, following application of nucleic acids isolated from both untreated and treated cells to one or more of the specialized microarrays, the pattern of gene expression of the tested cells can be determined and compared with that of the biomarker pattern from the control panel of cells used to create the biomarker set on the microarray. Based upon the gene expression pattern results from the cells that underwent testing, it can be determined if the cells show a sensitive profile of gene expression. Whether or not the tested cells from a tissue or organ biopsy will respond to one or more of the CTLA-4 antagonists and the course of treatment or therapy can then be determined or evaluated based on the information gleaned from the results of the specialized microarray analysis.
Antibodies
[0066] The invention also includes antibodies, including polyclonal or monoclonal, directed against one or more of the polypeptide biomarkers. Such antibodies can be used in a variety of ways, for example, to purify, detect, and target the biomarkers of the invention, including both in vitro and in vivo diagnostic, detection, screening, and/or therapeutic methods.
Kits
[0067] The invention also includes kits for determining or predicting whether a patient would be susceptible to a treatment that comprises one or more CTLA-4 antagonists. The patient may have a cancer or tumor such as, for example, colorectal cancer. Such kits would be useful in a clinical setting for use in testing a patient's biopsied tumor or other cancer samples, for example, to determine or predict if the patient's tumor or cancer will be sensitive to a given treatment or therapy with an CTLA-4 antagonist. The kit comprises a suitable container that comprises: one or more microarrays, e.g., oligonucleotide microarrays or cDNA microarrays, that comprise those biomarkers that correlate with sensitivity to CTLA-4 antagonists, particularly CTLA-4 inhibitors; one or more CTLA-4 antagonists for use in testing cells from patient tissue specimens or patient samples; and instructions for use. In addition, kits contemplated by the invention can further include, for example, reagents or materials for monitoring the expression of biomarkers of the invention at the level of mRNA or protein, using other techniques and systems practiced in the art such as, for example, RT-PCR assays, which employ primers designed on the basis of one or more of the biomarkers described herein, immunoassays, such as enzyme linked immunosorbent assays (ELISAs), immunoblotting, e.g., Western blots, or in situ hybridization, and the like.
Application of Biomarkers and Biomarker Sets
[0068] The biomarkers and biomarker sets may be used in different applications.
[0069] Biomarker sets can be built from any combination of biomarkers to make predictions about the effect of an CTLA-4 antagonist in different biological systems. The various biomarkers and biomarkers sets described herein can be used, for example, as diagnostic or prognostic indicators in disease management, to predict how patients with cancer might respond to therapeutic intervention with compounds that modulate the CTLA-4, and to predict how patients might respond to therapeutic intervention that modulates signaling through the entire CTLA-4 regulatory pathway.
[0070] The biomarkers have both diagnostic and prognostic value in diseases areas in which signaling through CTLA-4 or the CTLA-4 pathway is of importance, e.g., in immunology, or in cancers or tumors in which cell signaling and/or proliferation controls have gone awry.
[0071] In one aspect, cells from a patient tissue sample, e.g., a tumor or cancer biopsy, can be assayed to determine the expression pattern of one or more biomarkers prior to treatment with one or more CTLA-4 antagonists. In one aspect, the tumor or cancer is colorectal. Success or failure of a treatment can be determined based on the biomarker expression pattern of the cells from the test tissue (test cells), e.g., tumor or cancer biopsy, as being relatively similar or different from the expression pattern of a control set of the one or more biomarkers. Thus, if the test cells show a biomarker expression profile which corresponds to that of the biomarkers in the control panel of cells which are sensitive to the CTLA-4 antagonist, it is highly likely or predicted that the individual's cancer or tumor will respond favorably to treatment with the CTLA-4 antagonist.
[0072] The invention also provides a method of monitoring the treatment of a patient having a disease treatable by one or more CTLA-4 antagonists. The isolated test cells from the patient's tissue sample, e.g., a tumor biopsy or tumor sample, can be assayed to determine the expression pattern of one or more biomarkers before and after exposure to an CTLA-4 antagonist wherein, preferably, the CTLA-4 antagonist is an CTLA-4 inhibitor. The resulting biomarker expression profile of the test cells before and after treatment is compared with that of one or more biomarkers as described and shown herein to be highly expressed in the control panel of cells that are sensitive to an CTLA-4 antagonist. Thus, if a patient's response is sensitive to treatment by an CTLA-4 antagonist, based on correlation of the expression profile of the one or biomarkers, the patient's treatment prognosis can be qualified as favorable and treatment can continue. Also, if, after treatment with an CTLA-4 antagonist, the test cells don't show a change in the biomarker expression profile corresponding to the control panel of cells that are sensitive to the CTLA-4 antagonist, it can serve as an indicator that the current treatment should be modified, changed, or even discontinued. This monitoring process can indicate success or failure of a patient's treatment with an CTLA-4 antagonist and such monitoring processes can be repeated as necessary or desired.
EXAMPLES
[0073] In Examples 1 and 2, the effect of an anti-CTLA4 antibody (UC10) was investigated on the biomarker patterns in a sensitive mouse tumor model (Sa1N fibrosarcoma) and a resistant model (EMT6 mammary carcinoma). UC10 is known in the art and is described, for example, in T. Walunas et al., Immunity., August; 1(5):405-13 (1994).
RNA Isolation:
[0074] In the Sa1N model, UC10 induced the infiltration of T cells into the tumor. The gene expression analysis supported this by detecting the induction of various immune response genes including interferon gamma, granzyme B and perforin 1. Gene expression data also indicated the activation of humoral immunity and antigen presentation in the tumor. The activation of interferon gamma, granzyme B and perforin 1 genes was also observed in the peripheral blood. These result indicated the checkpoint blockade by the anti-CTLA4 antibody induced a wide range of immune responses, including those that are crucial to the anti-tumor response.
[0075] On the other hand, the effect of UC10 on the EMT6 (resistant model) was entirely different. There, we observed no increase of tumor infiltrating lymphocytes, and no induction of interferon gamma, granzyme B and perforin 1 in the tumor. Thus, a biomarker signal of anti-tumor immunity was not detected in this model. Thus, it appears UC10 failed to modulate any immune response to EMT6 tumors.
[0076] However, in the peripheral blood of mice bearing EMT6 tumors, UC10 induced the genes that were the hallmark of alternatively activated macrophages (M2), such as Ym1, Fizz1, and arginase 1.
[0077] Currently, it is not known what is the exact type of cell that expresses these genes in the peripheral blood. However, the close resemblance of the induced gene expression pattern with that of alternatively activated macrophages suggests that this type of macrophages or a related type of cells may be highly induced by the UC10 treatment in this model. Alternatively, activated macrophages can be induced by Th2 cytokines and are known to dampen the anti-tumor immune response at least in some cases. Balb/c mice (host of EMT6 tumor) are genetically predisposed to the Th2 response, and the induction of alternatively activated macrophage type genes by CTLA4 blockade with UC10 may be due to this genetic predisposition of the host mice. This may be one of the reasons why this anti-CTLA4 antibody was unable to mount an effective anti-tumor immunity in this model.
[0078] In Examples 1 and 2, tumor samples were collected in RNAlater reagent (Ambion, Inc., Austin, Tex.) following the manufacturer's manual. Tumor RNA was extracted using Qiagen RNAeasy mini kit. The quality of isolated RNA was confirmed using Agilent 2100 nucleic acid analyzer detecting the peaks for 18S and 28S rRNA.
Affymetrix GeneChip Process for Examples 1 and 2:
[0079] Mouse GeneChip 430A, v2.0 was used and globin reduction pretreatment was required. Experimental process (cDNA synthesis, in vitro transcription/IVT, and GeneChip hybridization) followed the standard Affymetrix manual. Transcriptional profiling was performed on the RNA obtained from the tumor samples. The Affymetrix GeneChip system (Affymetrix, Santa Clara, Calif.) was used for hybridization and scanning of the mouse 430A arrays. Data were preprocessed using the MAS 5.0 software. Generation of cRNA followed a standard T7 amplification protocol. Total RNA was reverse-transcribed with SuperScript II (Gibco, Carlsbad, Calif.) in the presence of T7-(dT) 24 primer to generate first strand cDNA. A second-strand cDNA synthesis was performed in the presence of DNA Polymerase I, DNA ligase, and RNase H (Gibco). The resulting double-stranded cDNA was blunt-ended using T4 DNA polymerase. This double-stranded cDNA was then transcribed into cRNA in the presence of biotin-ribonucleotides using the BioArray High Yield RNA transcript labeling kit (Enzo Life Sciences, Farmingdale, N.Y.). The amplified, biotin-labeled cRNA was purified using Qiagen RNeasy columns (Qiagen Sciences), quantified and fragmented at 94° C. for 35 minutes in the presence of fragmentation buffer (1×). Fragmented cRNA was hybridized to the Affymetrix 430A arrays overnight at 42° C. The arrays were then placed in the fluidics stations for staining and washing as recommended by Affymetrix protocols. The chips were scanned and raw intensity values were generated for each probe on the arrays. The trimmed mean intensity for each array was scaled to 1,500 to account for minor differences in global chip intensity so that the overall expression level for each sample was comparable.
Data Analysis for Examples 1 and 2:
[0080] The GeneChip data was uploaded to PartekPro Pattern Recognition software (Partek, St. Louis, Mo.) for data analysis after using the RMA (Robust Multi-array Analysis) normalization procedure (Irizarry et al., Biostatistics, April; 4(2):249-64 (2003)) with a log 2 transformation.
Example 1
Identification of Biomarkers Using Sa1N Mouse Tumor Model
[0081] The effect of the anti-CTLA4 monoclonal antibody UC10 was studied on various biomarkers in the Sa1N fibrosarcoma model. (D. Leach et al., J. Immunol., January 15; 154(2):738-43 (1995))
[0082] Tumor and peripheral blood samples were collected for RNA analysis. Both the tumor and the blood RNA samples were analyzed by quantitative real-time PCR (qPCR). This was followed up by RNA expression profile analysis of the tumor samples using Affymetrix GeneChip.
Animal Sample Collection:
[0083] SA1N tumor cells were injected in the subcutaneous space of A/J mice. Treatments were initiated on day 6 post implantation when the subcutaneous tumor reached a median size of approximately 145-160 mm 3 . 0.3125, 1.25, 5, or 20 mg/kg of anti-CTLA4 monoclonal antibody UC10 or 0.2 mL of PBS (phosphate buffered saline) was injected intraperitoneally every three days for three doses (q3dx3). At days 4 (one day post second injection), 7 (one day post third injection), and 11 (seven days post third injection), four mice from each treatment arm were sacrificed.
[0084] As shown in FIG. 1 , UC10 treatments resulted in complete regressions of SA1N tumors in >50% of mice at doses>0.3 mg/kg.
SA1N Immunohistochemistry Staining:
[0085] Tumors were collected and frozen 1 day following the third dose of anti-CTLA-4 mAb (5 mg/kg, day 7). Tumor sections were stained with anti-mouse CD4 and anti-mouse CD8 monoclonal antibodies (BD Pharmingen). Higher infiltration of CD4 and CD8 T cells were observed in tumors from animals treated with anti-CTLA-4 mAb vs. control mice ( FIG. 2 )
[0000] Expansion of T Cells with an Effector/Memory Phenotype Following Anti-CTLA-4 Treatment:
[0086] UC10 did not affect frequencies of CD4 or CD8 T cells in blood at the times tested. However, an expansion of CD44high was observed preferentially in the CD8 T cell subset, suggesting an induction of an effector/memory T cell response. ( FIG. 3A and FIG. 3B )
[0000] qPCR Analysis:
[0087] Tumor RNA samples were analyzed by quantitative PCR (qPCR) using Taqman assay on demand reagents (Applied Biosystems) and results are illustrated in FIG. 4 . Interferon-gamma and cytotoxic T-cell effector genes (granzyme B and perforin 1) as well as T cell marker genes (Cd3d, Cd4, Cd8b1; not shown) were induced by UC10 in the tumor. The gene for indoleamine-pyrrole 2,3 dioxygenase (IDO) was also induced. IDO is an interferon-gamma inducible gene and can potentially be immunosuppressive.
[0088] Quantitative PCR (qPCR) analysis of peripheral blood RNA was also performed and the results are illustrated in FIG. 5 . Interferon gamma, Cd8b1, granzyme B and perforin 1 genes were all induced in the peripheral blood by UC10. The expression of interferon gamma, granzyme B and Cd8b1 was highest at day 7 (one day after the 3rd injection), and it also was higher at the fully efficacious dose (5 mg/kg) than at the sub-optimal dose (0.5 mg/kg).
Tumor RNA Expression Analysis:
[0089] The tumor cells were collected and tumor RNA extracted as described above. The Affymetrix GeneChip process and data analysis as described above.
RNA Expression Profiling:
[0090] To further identify genes induced by UC10 in the tumor, the same RNA samples were analyzed by RNA expression profiling using Affymetrix mouse A430 — 2 GeneChip.
[0091] The RNA expression data was exported from Xpress using the RMA method with log 2 transformation. The entire data was loaded onto Partek software and the subsequent analysis was performed using this software. Initially, the genes were filtered to select for those with a reliable signal and inter sample variations, applying the following two criteria: (i) CV>10% (to remove the genes that did not have significant variation among different samples); and (ii) the maximal signal >5 (to select genes with a reliable expression level at least in one of the samples).
[0092] The genes induced by UC10 were identified using a t-test comparing the expression levels in all the UC10 treated samples (all time points combined) and the control samples (all the time points combined) and are provided in Table 1A.
[0000] TABLE 1A Top 30 genes induced by UC10 (ranked by p-values) Fold Probe Set ID Gene Symbol p-value change 1419762_at Ubd 7.56E−07 6.18 1422527_at H2-DMa 2.53E−06 5.67 1424923_at Serpina3g 4.07E−06 6.26 1418641_at Lcp2 4.20E−06 3.05 1418638_at — 7.49E−06 2.62 1449556_at H2-T23 /// C920025E04Rik 1.20E−05 2.77 1419004_s_at Bcl2a1a /// Bcl2a1b /// Bcl2a1d 1.46E−05 2.89 1450678_at — 1.49E−05 3.01 1449580_s_at H2-DMb1 /// H2-DMb2 1.96E−05 4.90 1420915_at Stat1 2.64E−05 2.76 1460218_at Cd52 2.89E−05 4.96 1417025_at H2-Eb1 3.69E−05 7.30 1425477_x_at H2-Ab1 /// Rmcs1 3.77E−05 5.26 1451721_a_at H2-Ab1 4.43E−05 5.49 1419060_at Gzmb 4.62E−05 4.50 1452117_a_at Fyb 4.84E−05 3.34 1433741_at Cd38 5.22E−05 3.34 1450648_s_at H2-Ab1 /// Rmcs1 5.43E−05 5.73 1448786_at 1100001H23Rik 5.65E−05 3.10 1435176_a_at Idb2 6.76E−05 2.69 1422124_a_at Ptprc 6.82E−05 4.90 1450753_at Nkg7 6.88E−05 3.75 1425519_a_at Ii 8.26E−05 5.42 1454268_a_at Cyba 8.64E−05 2.52 1416016_at — 8.67E−05 2.18 1431008_at 0610037M15Rik 8.68E−05 3.08 1451318_a_at Lyn 8.78E−05 2.30 1416296_at — 9.83E−05 3.35 1422903_at Ly86 0.0001101 3.32 1423467_at Ms4a4b 0.0001104 12.83
The top 15 genes (probes) of Table 1A included various class II MHC genes as well as other genes important in immune response. Various other genes involved in T cell and B cell activation were also induced. Table 1 provides the biomarkers of Table 1A.
[0000] TABLE 1 Biomarkers of Table 1A Protein DNA SEQ NCBI Gene Gene Probe SEQ DNA ID Protein Entry (LocusLink) Title Symbol Set ID ID NO: Accession NO: Accession 1 Ubiquitin D Ubd 1419762_at 1 NM_023137.2 2 NP_075626.1 2 Histocompatibility H2- 1422527_at 3 AK146950.1 4 BAE27559.1 2, class II, locus DMa DMa {POOR HIT (66%) 66%} 3 Serine (Or cysteine) Serpina 1424923_at 5 NM_009251.1 6 NP_033277.1 peptidase inhibitor, 3g clade A, member 3G 4 Lymphocyte Lcp2 1418641_at 7 NM_010696.3 8 NP_034826.2 cytosolic protein 2 5 Histocompatibility H2- 1418638_at 9; 11 AK170866.1; 10; 12 BAE42080.1; 2, class II, locus DMb1 BC002237.1 AAH02237.1 Mb1 (??) {UNVALIDATED} 6 similar to H-2 class N/A; 1449556_at 13; 15; NM_010398.1; 14; 16; NP_034528.1; I histocompatibility N/A; 17; 19; XM_904658.2; 18; 20 XP_909751.1; antigen, D-37 alpha N/A; 21 XM_975970.1; XP_981064.1; chain precursor; H2-T23 XM_992574.1; XP_997668.1 similar to H-2 class XR_003960.1 I histocompatibility antigen, D-37 alpha chain precursor; similar to H-2 class I histocompatibility antigen, D-37 alpha chain precursor; histocompatibility 2, T region locus 23 7 B-cell Bcl2a1a; 1419004_s_at 22; 24; NM_007534.1; 23; 25; NP_031560.1; leukemia/lymphoma Bcl2a1b; 26 NM_007536.2; 27 NP_031562.1; 2 related protein Bcl2a1d NM_009742.3 NP_033872.1 A1a; B-cell leukemia/lymphoma 2 related protein A1b; B-cell leukemia/lymphoma 2 related protein A1d 8 Integrin beta 2 Itgb2 1450678_at 28 NM_008404.2 29 NP_032430.2 9 Histocompatibility H2- 1449580_s_at 30; 32 NM_010387.2; 31; 33 NP_034517.2; 2, class II, locus DMb1; NM_010388.2 NP_034518.1 Mb1; H2- histocompatibility DMb2 2, class II, locus Mb2 10 Signal transducer Stat1 1420915_at 34 NM_009283.3 35 NP_033309.3 and activator of transcription 1 11 CD52 antigen Cd52 1460218_at 36 NM_013706.1 37 NP_038734.1 12 N/A; N/A; 1417025_at 38; 39 AK005018.1; 40 BAE33527.1 histocompatibility H2-Eb1 AK155968.1 2, class II antigen E (74%) beta {POOR HIT 74%} 13 Histocompatibility H2-Ab1 1425477_x_at 41; 43 M15848.1; 42; 44 AAA39547.1; 2, class II antigen (72%) NM_207105.1 NP_99698.1 A, beta 1 {POOR HIT 72%} 14 N/A; N/A; 1451721_a_at 41; 45; M15848.1; 42; 46; AAA39547.1; Histocompatibility H2-Ab1 47; 49; BC008168.1; 48; 51; AAH08168.1; 2, class II antigen 50; 52 BC057998.1; 53 AAH57998.1; A, beta 1 ENSMUST00000040828.4; AAA39633.1; M13537.1; AAA39635.1 M13539.1 15 !! [Gzmb] 1419060_at 54 ENSMUST00000015581.3 Granzyme B 16 FYN binding Fyb 1452117_a_at 55 NM_011815.1 56 NP_035945.1 protein 17 CD38 antigen Cd38 1433741_at 57 NM_007646.2 58 NP_031672.2 18 Histocompatibility H2-Ab1 1450648_s_at 43 NM_207105.1 44 NP_996988.1 2, class II antigen A, beta 1 19 RIKEN cDNA 1100001H23Rik 1448786_at 59; 61; NM_025806.1; 60; 62; NP_080082.1; 1100001H23 gene 63 XM_974622.1; 64 XP_979716.1; XM_974657.1 XP_979751.1 20 N/A; Inhibitor of N/A; 1435176_a_at 65; 66; BF019883.1; 68 NP_034626.1 DNA binding 2 Id2 67 ENSMUST00000020974.3; NM_010496.2 21 Protein tyrosine Ptprc 1422124_a_at 69 NM_011210.2 70 NP_035340.2 phosphatase, receptor type, C 22 Natural killer cell Nkg7 1450753_at 71 NM_024253.4 72 NP_077215.2 group 7 sequence 23 CD74 antigen Cd74 1425519_a_at 73 NM_010545.3 74 NP_034675.1 (invariant polypeptide of major histocompatibility complex, class II antigen-associated) 24 Cytochrome b-245, Cyba 1454268_a_at 75 NM_007806.1 76 NP_031832.1 alpha polypeptide 25 N/A; transporter 1, N/A; 1416016_at 77; 78; AK166046.1; AW048052.1; ATP-binding Tap1 79 ENSMUST00000041633.5 cassette, sub-family (74%) B (MDR/TAP) {POOR HIT 74%} 26 RIKEN cDNA 0610037M15Rik 1431008_at 80 XM_903697.2 81 XP_908790.2 0610037M15 gene 27 similar to N/A; 1451318_a_at 82; 84; NM_010747.1; 83; 85; NP_034877.1; Yamaguchi sarcoma Lyn 86 XM_973394.1; 87 XP_978488.1; viral (v-yes-1) XM_991890.1 XP_996984.1 oncogene homolog; Yamaguchi sarcoma viral (V-yes-1) oncogene homolog 28 N/A; interleukin 2 N/A; 1416296_at 88; 89 ENSMUST00000033664.5; 90 AAA39286.1 receptor, gamma Il2rg L20048.1 chain 29 !! [Ly86] 1422903_at 91 ENSMUST00000021860.3 Lymphocyte antigen 86 30 membrane-spanning Ms4a4b 1423467_at 92 NM_021718.2 93 NP_068364.1 4-domains, subfamily A, member 4B
Table 2 provides the top genes of Table 1A inducted by UC10 ranked by fold changes.
[0000]
TABLE 2
Top genes induced by UC10 (ranked by fold changes)
Probe Set ID
Gene Symbol
p-value
Fold change
1425324_x_at
Igh-4
0.0024827
42.01
1425247_a_at
Igh-4
0.0026075
33.24
1427455_x_at
Igk-V8
0.0012493
31.51
1424305_at
Igj
0.0037365
29.12
1427756_x_at
Igh-4
0.0037902
26.47
1452463_x_at
Igk-V8
0.0022802
23.03
1452417_x_at
2010205A11Rik
0.0018467
20.49
1427660_x_at
Igk-V8
0.0015737
20.02
1451632_a_at
Igh-6
0.0067362
20.02
1427351_s_at
Igh-6
0.00119
19.43
1430523_s_at
Igl-V1
0.0058301
16.77
1424931_s_at
Igl-V1
0.0060744
16.38
1427329_a_at
Igh-6
0.0039934
15.09
1427870_x_at
Igh-4
0.0041593
14.59
1423467_at
Ms4a4b
0.0001104
12.83
1424825_a_at
Glycam1
0.0074547
11.35
1425738_at
LOC243469
0.0070091
10.97
1419426_s_at
Ccl21b /// Ccl21a /// Ccl21c
0.0077637
9.96
1425871_a_at
LOC384413 /// LOC434038
0.0147353
9.93
1417851_at
Cxcl13
0.0004093
9.67
1426772_x_at
Tcrb-V13
0.0010696
9.47
1426113_x_at
Tcra
0.0005445
9.26
1425226_x_at
Tcrb-V13
0.0011634
8.66
1448377_at
Slpi
0.003984
8.46
1452205_x_at
Tcrb-V13
0.0020205
8.18
1426174_s_at
Ighg
0.0095374
8.05
1417640_at
Cd79b
0.00978
8.00
1452557_a_at
—
0.0058116
7.93
1425854_x_at
Tcrb-V13
0.002944
7.58
1422828_at
Cd3d
0.0018528
7.52
[0093] FIG. 6 illustrates the expression levels of T cell receptor beta, immunoglobulin, and class II MHC genes in the tumor RNA expression profile analysis. These genes were induced by UC10 treatment, suggesting the infiltration of T, B, and possibly antigen presenting cells as well in the tumor.
[0094] Ubd (FAT10/diubiquitin) gene was induced strongly by UC10 treatment. This gene may be a marker for the activation of anti-tumor immunity. Ubd gene is known to be induced by IFN-gamma and TNF-alpha, but its role in anti-immune response has not been described in the literature. (A. Canaan et al., Mol. Cell. Biol., July; 26(13):5180-9 (2006); E. Bates et al., Eur. J. Immunol., October; 27(10):2471-7 (1997))
Example 2
Identification of Biomarkers Using EMT-6 Mouse Tumor Model
[0095] The effect of UC10 vs. control (hamster IgG) was studied. Initially, tumor and blood total RNA were analyzed by qPCR. This was followed by RNA expression profile analysis using Affymetrix GeneChip.
Animal Sample Collection:
[0096] EMT6 mouse mammary tumor was maintained in vitro. (Rockwell and Kallman, Radiat Res., February; 53(2):281-94 (1973)) EMT6 tumor cells were injected in the subcutaneous space of the right flank of Balb/c mice. Treatments were initiated when the subcutaneous tumor reached a median size between 100-200 mm 3 . 4.5 mg/kg of UC10 or Hamster IgG was injected intravenously once per week for three weeks (q7dx3 IV). At 24h after the third treatment of UC10, four mice were sacrificed. At seven days after the third treatment of hamster IgG, four mice were sacrificed.
[0097] Separately, anti-tumor activity of UC10 was studied in EMT6 tumor cells. The results are provided in FIG. 7 , wherein UC10 treatments resulted in no activity at doses as high as 39 mg/kg.
[0000] RNA Expression Analysis by Quantitative PCR (qPCR):
[0098] Tumor and blood samples were collected from these mice. Tumors were collected in RNAlater, while blood samples were collected in PAXgene tubes. Total RNA was extracted from the blood using PAXgene RNA extraction kit. Tumor RNA was extracted using Qiagene RNAeasy mini kit. The quality of isolated RNA was confirmed using Agilent 2100 nucleic acid analyzer detecting the peaks for 18S and 28S rRNA. cDNA was synthesized with a reverse transcription kit (Applied Biosystems) using random hexamers as primers.
[0099] qPCR was performed using the Taqman method using Applied Biosystems (AB)'s ‘Assay on Demand (AoD)’ premade assays. Some of the analysis was done using individual Taqman reagents in 96-well formats. Other assays were performed using Taqman Low Density Array (TLDA) microfluidic card system. All of these assays were run on the 7900HT sequence detection machine (AB).
Tumor Result:
[0100] Tumor qPCR analysis was done for all the samples including the UC10 treated arm. FIG. 8 illustrates the EMT6 tumor RNA qPCR results. As shown in FIG. 8 , EMT6 model does not respond to the UC10 treatment. In this model, UC10 did not induce the induction of interferon gamma, granzyme B, or perforin 1 genes suggesting there was no activation of the immune response in the tumor.
Blood Result:
[0101] The same set of genes were analyzed in the blood. As illustrated in FIG. 9 , UC10 did not induce granzyme B or perforin 1 gene expression in the blood of EMT6 model. This contrasted with the Sa1N model, again reflecting the lack of anti-tumor response in this model.
Tumor RNA Expression Analysis:
[0102] The tumor cells were collected and tumor RNA extracted as described above. The Affymetrix GeneChip process and data analysis as described above. The blood analysis protocol was identical to the tumor analysis, except for the globin reduction pretreatment that was required since a pilot experiment indicated that mouse blood RNA generated a poor quality RNA expression data without the globin reduction process. Globin reduction was performed using the Ambion protocol following the manufacturer's manual.
[0103] UC10 effect was analyzed for one time point (1 day after the third treatment), as this was the only time the samples were collected. The analysis was done as a one-way ANOVA (essentially a t-test) using Partek software. None of the genes appeared to be changed significantly by UC10. Also, the genes with the lowest p-value for treatment effect appeared from random from various pathways. This reflects the efficacy results.
Blood RNA Expression Analysis:
[0104] To further identify genes induced by UC10 in the blood, the same RNA samples were analyzed by RNA expression profiling using Affymetrix mouse A430 — 2 GeneChip.
[0105] The RNA expression data was exported from Xpress using the RMA method with log 2 transformation. The entire data was loaded onto Partek software and the subsequent analysis was performed using this software. Initially, the genes were filtered to select for those with a reliable signal and inter sample variations, applying the following two criteria: (i) CV>10% (to remove the genes that did not have significant variation among different samples); and (ii) the maximal signal >6.6 (to select genes with a reliable expression level at least in one of the samples), which corresponds to the signal of 100 without log 2 transformation.
[0106] The top 29 genes (probes) based on the p-value are provided in Table 3A.
[0000] TABLE 3A Top 29 genes induced by UC10 (ranked by p-values) Fold p- Probe Set ID Gene Symbol Gene Title change value (treatment) 1425295_at Ear11 eosinophil-associated, 30.75 0.00030 ribonuclease A family, member 11 1419764_at Chi3l3 chitinase 3-like 3 46.74 0.00046 1455530_at — — 0.37 0.00059 1422122_at Fcer2a Fc receptor, IgE, low affinity 0.34 0.00098 II, alpha polypeptide 1416746_at H2afx H2A histone family, 2.51 0.00156 member X 1425451_s_at Chi3l3 /// chitinase 3-like 3 /// 20.60 0.00176 Chi3l4 chitinase 3-like 4 1419549_at Arg1 arginase 1, liver 24.05 0.00205 1449015_at Retnla resistin like alpha 7.98 0.00239 1420249_s_at Ccl6 chemokine (C-C motif) 2.94 0.00285 ligand 6 1450430_at Mrc1 mannose receptor, C type 1 6.34 0.00558 1455106_a_at Ckb creatine kinase, brain 3.63 0.00567 1419515_at Fgd2 FYVE, RhoGEF and PH 3.00 0.00582 domain containing 2 1417936_at Ccl9 chemokine (C-C motif) 3.15 0.00628 ligand 9 1448898_at Ccl9 chemokine (C-C motif) 3.04 0.00783 ligand 9 1418509_at Cbr2 carbonyl reductase 2 5.46 0.00817 1417346_at Pycard PYD and CARD domain 2.01 0.00897 containing 1425469_a_at — — 2.07 0.00900 1438009_at Hist1h2ad Histone 1, H2ae, mRNA 3.20 0.00945 (cDNA clone MGC: 90847 IMAGE: 5713252) /// CDNA clone MGC: 103288 IMAGE: 5150365 1423756_s_at Igfbp4 insulin-like growth factor 0.45 0.01371 binding protein 4 1455332_x_at Fcgr2b Fc receptor, IgG, low 2.80 0.01505 affinity IIb 1451941_a_at Fcgr2b Fc receptor, IgG, low 3.88 0.01528 affinity IIb 1434437_x_at Rrm2 ribonucleotide reductase M2 3.78 0.01718 1435476_a_at Fcgr2b Fc receptor, IgG, low 2.41 0.01721 affinity IIb 1448883_at Lgmn legumain 2.15 0.01815 1435477_s_at Fcgr2b Fc receptor, IgG, low 3.23 0.02094 affinity IIb 1460287_at Timp2 tissue inhibitor of 3.14 0.02462 metalloproteinase 2 1416108_a_at Tmed3 transmembrane emp24 1.87 0.02477 domain containing 3 1416713_at 2700055K07Rik RIKEN cDNA 2700055K07 2.32 0.02703 gene 1430523_s_at Igl-V1 immunoglobulin lambda 1.99 0.02782 chain, variable 1
Table 3 provides the biomarkers of Table 3A.
[0000]
TABLE 3
Biomarkers of Table 3A
DNA
NCBI Gene
SEQ
Protein
(LocusLink)
Gene
Probe Set
ID
DNA
SEQ ID
Protein
Entry
Title
Symbol
ID
NO:
Accession
NO:
Accession
1
Eosinophil-
Ear11
1425295_at
94
NM_053113.2
95
NP_444343.2
associated,
ribonuclease
A family,
member 11
2
chitinase 3-
Chi313
1419764_at
96
XM_992616.1
97
XP_997710.1
like 3
3
!! uv90d11.x1 Soares
1455530_at
98
BE686052.1
mouse 3NbMS Mus
musculus cDNA clone
IMAGE: 3414453 3′,
mRNA sequence
4
Fc receptor,
Fcer2a
1422122_at
99
NM_013517.1
100
NP_038545.1
IgE, low
affinity II,
alpha
polypeptide
5
H2A
H2afx
1416746_at
101
NM_010436.2
102
NP_034566.1
histone
family,
member X
6
chitinase 3-
Chi313;
1425451_s_at
96;
XM_992616.1;
97; 104;
XP_997710.1;
like 3;
Chi314
103;
NM_009892.1;
106
NP_034022.1;
chitinase 3-
105
NM_145126.1
NP_660108.1
like 4
7
N/A;
N/A;
1419549_at
107;
BC050005.1;
108; 111
AAH50005.2;
arginase 1,
Arg1
109;
ENSMUST00000020161.5;
AAA98611.1
liver
(65%)
110
U51805.1
{POOR
HIT 65%}
8
resistin like
Retnla
1449015_at
112
NM_020509.3
113
NP_065255.2
alpha
9
chemokine
Cc16
1420249_s_at
114
NM_009139.3
115
NP_033165.1
(C-C motif)
ligand 6
10
Mannose
Mrc1
1450430_at
116
NM_008625.1
117
NP_032651.1
receptor, C
type 1
11
N/A;
N/A;
1455106_a_at
118;
AK165779.1;
122
NP_067248.1
Creatine
Ckb
119;
BG967663.1;
kinase,
120;
ENSMUST00000001304.5;
brain
121
NM_021273.3
12
!! [Fgd2]
1419515_at
123
ENSMUST00000024810.4
FYVE,
RhoGEF
and PH
domain
containing 2
13
Chemokine
Ccl9
1417936_at
124;
AF128196.1;
125; 127
AAF22537.1;
(C-C motif)
126
NM_011338.2
NP_035468.1
ligand 9
14
Chemokine
Ccl9
1448898_at
126
NM_011338.2
127
NP_035468.1
(C-C motif)
ligand 9
15
Carbonyl
Cbr2
1418509_at
128
NM_007621.1
129
NP_031647.1
reductase 2
16
PYD and
Pycard
1417346_at
130
NM_023258.3
131
NP_075747.2
CARD
domain
containing
17
!! hypothetical protein
1425469_a_at
132;
AK085738.1;
134
AAH03855.1
LOC624610||
133
BC003855.1
hypothetical protein
LOC675730 || similar
to IG KAPPA CHAIN
V-V REGION L6
PRECURSOR
18
Similar to
MGC73635
1438009_at
135;
XM_978296.1;
136; 138
XP_983390.1;
histone 2a
(*)
137
XM_978341.1
XP_983435.1
19
Insulin-like
Igfbp4
1423756_s_at
139
NM_010517.3
140
NP_034647.1
growth
factor
binding
protein 4
20
N/A; Fc
N/A;
1455332_x_at
141;
BM224327.2;
143
NP_034317.1
receptor,
Fcgr2b
142
NM_010187.2
IgG, low
affinity IIb
21
Fc receptor,
Fcgr2b
1451941_a_at
142
NM_010187.2
143
NP_034317.1
IgG, low
affinity IIb
22
ribonucleotide
Rrm2
1434437_x_at
144
NM_009104.1
145
NP_033130.1
reductase
M2
23
Fc receptor,
Fcgr2b
1435476_a_at
142
NM_010187.2
143
NP_034317.1
IgG, low
affinity IIb
24
!! [Lgmn]
1448883_at
146
ENSMUST00000021607.5
Legumain
25
Fc receptor,
Fcgr2b
1435477_s_at
142
NM_010187.2
143
NP_034317.1
IgG, low
affinity IIb
26
Tissue
Timp2
1460287_at
147
NM_011594.3
148
NP_035724.2
inhibitor of
metalloproteinase 2
27
Transmembrane
Tmed3
1416108_a_at
149
NM_025360.1
150
NP_079636.1
emp24
domain
containing 3
28
RIKEN
2700055K07Rik
1416713_at
151
NM_026481.2
152
NP_080757.1
cDNA
2700055K07
gene
29
immunoglobulin
Igl-V1
1430523_s_at
153;
AK008094.1;
154; 156
BAB25455.1;
lambda
155;
AK008145.1;
BAB25493.1
chain,
157
AY170495.1
variable 1
[0107] The highest induction was seen with genes associated with Th2 response or alternative activation of macrophage. Both of these pathways can be anti-inflammatory, and may suppress anti-tumor immunity. It should be also noted that none of these patterns was observed in the tumor gene expression from the same mice.
[0108] Earl1 is one of the mouse versions of eosinophil cationic protein (ECP), which is one of the mediators of the Th2 response.
[0109] Tables 3A and 3 include genes associated with alternative activation of macrophages (Ym1, arginase 1 and Fizz 1). Arginasel, Chi313 (Ym1), Retnla (resistin-like alpha/Fizz1) have all been reported to be markers of alternatively activated macrophages in mice. (Nair et al., Immunol Lett., January 22; 85(2):173-80 (2003)) Mrc1 may also be involved in the type-2 activation of monocyte derived DCs, which can be anti-inflammatory. (Chieppa et al., J. Immunol., November 1; 171(9):4552-60 (2003))
[0110] Activation of creatine kinase has been observed during monocyte to macrophage development. (Loike et al., J Exp Med., March 1; 159(3):746-57 (1984))
[0111] The same blood RNA samples analyzed in FIG. 9 were analyzed for the expression of Ym1 and ariginase 1 and the results are provided in FIG. 10 . The induction of these genes by UC10 was reproduced, and the expression level was extremely high at day 7. This high expression of Ym1 and arginase 1 mostly disappeared by day 13.
Example 3
Production of Antibodies Against the Biomarkers
[0112] Antibodies against the biomarkers can be prepared by a variety of methods. For example, cells expressing a biomarker polypeptide can be administered to an animal to induce the production of sera containing polyclonal antibodies directed to the expressed polypeptides. In one aspect, the biomarker protein is prepared and isolated or otherwise purified to render it substantially free of natural contaminants, using techniques commonly practiced in the art. Such a preparation is then introduced into an animal in order to produce polyclonal antisera of greater specific activity for the expressed and isolated polypeptide.
[0113] In one aspect, the antibodies of the invention are monoclonal antibodies (or protein binding fragments thereof). Cells expressing the biomarker polypeptide can be cultured in any suitable tissue culture medium, however, it is preferable to culture cells in Earle's modified Eagle's medium supplemented to contain 10% fetal bovine serum (inactivated at about 56° C.), and supplemented to contain about 10 g/l nonessential amino acids, about 1.00 U/ml penicillin, and about 100 μg/ml streptomycin.
[0114] The splenocytes of immunized (and boosted) mice can be extracted and fused with a suitable myeloma cell line. Any suitable myeloma cell line can be employed in accordance with the invention, however, it is preferable to employ the parent myeloma cell line (SP2/0), available from the ATCC (Manassas, Va.). After fusion, the resulting hybridoma cells are selectively maintained in HAT medium, and then cloned by limiting dilution as described by Wands et al. (1981 , Gastroenterology, 80:225-232). The hybridoma cells obtained through such a selection are then assayed to identify those cell clones that secrete antibodies capable of binding to the polypeptide immunogen, or a portion thereof.
[0115] Alternatively, additional antibodies capable of binding to the biomarker polypeptide can be produced in a two-step procedure using anti-idiotypic antibodies. Such a method makes use of the fact that antibodies are themselves antigens and, therefore, it is possible to obtain an antibody that binds to a second antibody. In accordance with this method, protein specific antibodies can be used to immunize an animal, preferably a mouse. The splenocytes of such an immunized animal are then used to produce hybridoma cells, and the hybridoma cells are screened to identify clones that produce an antibody whose ability to bind to the protein-specific antibody can be blocked by the polypeptide. Such antibodies comprise anti-idiotypic antibodies to the protein-specific antibody and can be used to immunize an animal to induce the formation of further protein-specific antibodies.
Example 4
Immunofluorescence Assays
[0116] The following immunofluorescence protocol may be used, for example, to verify CTLA-4 biomarker protein expression on cells or, for example, to check for the presence of one or more antibodies that bind CTLA-4 biomarkers expressed on the surface of cells. Briefly, Lab-Tek II chamber slides are coated overnight at 4° C. with 10 micrograms/milliliter (μg/ml) of bovine collagen Type II in DPBS containing calcium and magnesium (DPBS++). The slides are then washed twice with cold DPBS++ and seeded with 8000 CHO—CCR5 or CHO pC4 transfected cells in a total volume of 125 μl and incubated at 37° C. in the presence of 95% oxygen/5% carbon dioxide.
[0117] The culture medium is gently removed by aspiration and the adherent cells are washed twice with DPBS++ at ambient temperature. The slides are blocked with DPBS++ containing 0.2% BSA (blocker) at 0-4° C. for one hour. The blocking solution is gently removed by aspiration, and 125 μl of antibody containing solution (an antibody containing solution may be, for example, a hybridoma culture supernatant which is usually used undiluted, or serum/plasma which is usually diluted, e.g., a dilution of about 1/100 dilution). The slides are incubated for 1 hour at 0-4° C. Antibody solutions are then gently removed by aspiration and the cells are washed five times with 400 μl of ice cold blocking solution. Next, 125 μl of 1 μg/ml rhodamine labeled secondary antibody (e.g., anti-human IgG) in blocker solution is added to the cells. Again, cells are incubated for 1 hour at 0-4° C.
[0118] The secondary antibody solution is then gently removed by aspiration and the cells are washed three times with 400 μl of ice cold blocking solution, and five times with cold DPBS++. The cells are then fixed with 125 μl of 3.7% formaldehyde in DPBS++ for 15 minutes at ambient temperature. Thereafter, the cells are washed five times with 400 μl of DPBS++ at ambient temperature. Finally, the cells are mounted in 50% aqueous glycerol and viewed in a fluorescence microscope using rhodamine filters. | CTLA-4 biomarkers useful in a method for predicting the likelihood that a mammal that will respond therapeutically to a method of treating cancer comprising administering an CTLA-4 antagonist, wherein the method comprises (a) measuring in the mammal the level of at least one biomarker s, (b) exposing a biological sample from the mammal to the CTLA-4 antagonist, and (c) following the exposing of step (b), measuring in the biological sample the level of the at least one biomarker, wherein an increase in the level of the at least one biomarker measured in step (c) compared to the level of the at least one biomarker measured in step (a) indicates an increased likelihood that the mammal will respond therapeutically to the method of treating cancer. | 2 |
FIELD OF THE INVENTION
This invention relates to an improved process for the deacylation and desulfurization of a compound having the formula: ##STR3## In the improved process of this invention hypophosphorous acid is employed in the deacylation and desulfurization to improve product yield and reduce the yield of unwanted impurities.
BACKGROUND OF THE INVENTION
Pyrazolotriazoles, such as those described herein are useful magenta couplers for photographic products. However, they are difficult to synthesize. Only a few synthetic routes are known. One of the preferred synthetic routes involves preparation of the triazolothiadiazines 1 and subsequent desulfurization reaction to give the pyrazolotriazoles 2. The triazolothiadiazines 1 can be prepared in two ways; the first, by reaction of 4-amino-5-mercapto-3-substituted(R)-1,2,4-triazoles (4) with alpha-haloketones, or the second, by reaction of 2-hydrazino-5-substituted-(R')-1,3,4-thiadiazines (5) with acyl halides and subsequent dehydrative ring closure. Both the triazoles 4 and the thiadiazines 5 are readily available from thiocarbohydrazide; ##STR4## The desulfurization of these triazolothiadiazines 1 to the pyrazolotriazoles 2: ##STR5## is effected in two steps; the first, a ring contraction reaction of 1 by heating in acetic anhydride to give 1-acetyl-7-acetylthio-3,6-disubstituted-1H-pyrazolo[5,1-c]-1,2,4-triazoles (6) and, the second, hydrolysis of acetyl groups and desulfurization at the same time with hydrochloric acid to give the desired 2. ##STR6## Although this is the most attractive and practical method for desulfurization among those available, there are several drawbacks in using this as a manufacturing process. The first ring contraction reaction is usually clean and does not render any problem except long reaction time. In fact, the reaction mixture is clean enough to be used in the next step without isolation of 6. However, the subsequent reactions are not straight-forward. The hydrolysis and desulfurization reactions with hydrochloric acid generate not only elemental sulfur as by-product but also many sulfur-containing organic impurities. Among them are two major impurities identified as thione 8 and disulfide 9. These oxidized forms of mercapto intermediate 7 seem to result by the action of elemental sulfur formed during the reaction of 7.
Not only elemental sulfur, but also the sulfur-containing organic impurities are considered detrimental. They can interfere with subsequent reaction steps, e.g. a catalytic hydrogenation of a nitro group on one of the groups R or R' in the above formulae. Also, sulfur is a potential fogger in photographic systems.
Because the process of this invention makes much smaller amounts of these detrimental impurities, and is straight-forward and readily carried out, it is considered to be a significant advance in the art.
SUMMARY OF THE INVENTION
This invention relates to an improved process for the preparation of certain pyrazolotriazoles from their triazolothiadiazine precursors. The improvement comprises a deacylation and desulfurization step conducted in the presence of hypophosphorous acid. Use of hypophosphorous acid reduces the amount of elemental sulfur and the amounts of sulfur-containing organic impurities which are formed when hypophosphorous acid is not used in the reaction mixture.
For example, if hypophosphorous acid is not used in a process for making the compound produced in Example 1, hereinbelow, the thione and disulfide impurities corresponding to formulas 8 and 9 can be produced in significant levels; 5-15 area percent as determined by LC/MS (liquid chromatography/mass spectrographic analysis). Without the hypophosphorous acid, the product of Example 1 is prepared in comparatively low yield, 45-50%. Apparently, the low yield is due to formation of the undesired impurities mentioned above.
In contrast, when the process of Example 1 is used, the desired pyrazolotriazole can be produced in 82% yield and with a purity of 98 area % by HPLC (high pressure liquid chromatography).
The use of hypophosphorous acid in the process of this invention has several advantages besides reducing the amounts of undesirable by-products and increasing the yield of the desired product. For example, use of hypophosphorous acid results in formation of H 2 S by-product rather than sulfur. In view of the gaseous nature of H 2 S and its chemical reactivity, it is readily removed from the reaction zone and trappel, for example, by caustic and sodium hypochlorite. Furthermore, hypophosphorous acid does not reduce nitro groups which are commonly present on side chains in photographic intermediates, or affect other functional groups in the molecule.
In summary, this invention overcomes significant difficulties and provides several advantages. For these reasons, and because the process is straight-forward and economical to carry out, it is readily adaptable by industry.
DESCRIPTION OF PREFERRED EMBODIMENTS
In a preferred embodiment, this invention provides the process for the preparation of a 3,6-di-substituted-1H-pyrazolo[5,1-c]-1,2,4-triazole having the formula: ##STR7## said process comprising reacting an acylated compound having the formula: ##STR8## with an aqueous mixture of hypophosphorous acid and hydrochloric acid or hydrobromic acid to produce hydrogen sulfide and said pyrazolotriazole;
R and R' and R" being inert substituents;
said process being characterized by generating less sulfur and sulfur-containing organic impurities than when no hypophosphorous acid is present.
In another preferred embodiment, this invention provides a process for the preparation of a 3,6-di-substituted-1H-pyrazolo[5,1-c]-1,2,4-triazole having the formula: ##STR9## from a 3,6-disubstituted-7H-1,2,4triazolo[3,4-b]-[1,3,4]thiadiazine having the formula: ##STR10## wherein R and R' are alike or different and are selected from photographically acceptable, inert substituents;
said process comprising: (i) reacting compound (I) with an acylating agent to form an acylated intermediate ##STR11## and (ii) subsequently reacting said acylated intermediate with an aqueous mixture of hypophosphorous acid and hydrochloric acid or hydrobromic acid to produce hydrogen sulfide and pyrazolotriazole (II);
said process being characterized by generating less sulfur and sulfur-containing organic impurities than when no hypophosphorous acid is present in step (ii).
In the compounds used as starting materials in this invention, and the compounds produced as intermediates, as well as the desired products, all represented by Formulas 1-9 above, R and R' are "inert substituents".
For the purpose of this invention, an "inert substituent" or "inert organic group" is defined by having the following characteristics:
(1) It is stable, or substantially stable, under the process conditions employed: i.e. it does not decompose to an untoward extent during process(es) employed in this invention.
(2) It is non-reactive, or substantially non-reactive toward the other reagents employed, i.e. it does not undergo an extraneous side reaction (to an unacceptable extent) with the other ingredient(s) used.
(3) It does not prevent, by steric hindrance or other mechanism or effect, the formation of a compound of this invention.
Thus, a wide variety of substituents may appear as R and/or R' in the above formulas. In other words, this invention is not critically dependent on the type(s) of groups designated R and R', so long as the groups meet criteria (1), (2) and (3) above. Typically, R and R' are hydrocarbyl groups, i.e. groups which are solely composed of carbon and hydrogen. However, it is not necessary that R and R' be solely composed of carbon and hydrogen; thus groups which comprise: ##STR12## NO 2 , --NH 2 , NHR, NRR, --SO 2 --, --S--, and alkoxy, aryloxy, the like, can appear in compounds of this invention, so long as the substituents meet the three criteria enumerated above. Alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl, aralkyl, heteroaryl groups and heterocyclic groups containing oxygen, sulfur or nitrogen as the heteroatom which meet the above criteria can be present in the compounds of this invention. These may be hydrocarbyl, or substituted hydrocarbyl groups, as discussed above. For convenience, R and R' are usually hydrocarbyl groups having up to about 20 carbon atoms; preferably they are hydrogen or alkyl or aryl groups of this type.
When the radical R" appears in compounds of this invention, it represents lower alkyl radicals, preferably those having up to about 6 carbon atoms. In compounds of this invention R and R' may be alike or different.
The R, R' and R" radicals are generally selected according to the properties that they confer on the compounds, and/or the role that they play in the selected utility. For example, since the radical R" appears in a group which is to be subsequently removed by hydrolysis, R" is preferably selected from a methyl or ethyl, or other lower alkyl group having up to about four carbon atoms in order to lower process costs.
On the other hand, the size or nature of the group may be selected because it is produced in a convenient reaction for preparing the pyrazolotriazole starting compound, or the group may be selected to confer some physical or chemical property, such as a desired degree of solubility, or a desired degree of compatibility with other ingredients in a mixture in which the product is used.
Moreover, one or more of the radicals R and R' may be selected to contain a radical which contains a reactive site. For example, R may be a group having the formula: ##STR13## wherein n is a whole number equal to 0 to about 6, and the nitro group is ortho, meta or para to the alkyl side chain. For some uses, it is desirable to subsequently reduce the aryl nitro group to an amino group. Accordingly, it is to be understood that the term "inert" in the phrase "inert substituent" does not mean that the substituent is unreactable in processing conducted after the compound is made.
As indicated above, compound (III) can be prepared by an acylation reaction. For the acylation an anhydride having the formula: ##STR14## is employed.
The acylating agent may be used in solvent quantities. There is no real upper limit on the amount of acylating agent; this being defined by such secondary characteristics as economics, size of the reaction vessel, ease of separation of product from the reaction mixture, ease of recovery of the unreacted acylating agent, etc.
The process may be conducted in the presence of a catalytic quantity of a Bronsted or Lewis acid. For the purpose of this invention, a Bronsted acid is any proton donor which donates a proton and does not hinder the process. Such materials are generally selected from alkyl sulfonic acids, hydrogen halides, sulfuric acid, and carboxylic acids such as those acids mentioned above for use as acylating agents. Lewis Acids, such as those employed for Friedel-Crafts acylations, e. c. AlCl 3 , FeCl 3 BF 3 , HF, H 3 PO 4 and the like, can also be used as catalysts.
Generally speaking, a catalytic amount of such catalyst, e.g. from about 0.05 to about 0.25 moles per mole of starting triazolothiadiazine is used. Greater or lesser amounts can be employed if they afford the desired result.
The acylation may be conducted at any convenient temperature which gives a reasonable rate of reaction, and which does not cause an undue amount of decomposition of one or more of the ingredients employed. Generally speaking, a temperature within the range of from about 20° C. to about 200° C. is employed; more preferably the temperature is from about 100° C. to about 150° C.
Ambient pressure is generally satisfactory. Higher pressures, up to 100 atmospheres or more can be used if one of the reagents is a gas or vapor at the reaction temperature.
The process is generally conducted in the substantial absence of water or with a small amount of water to prevent unwanted hydrolysis.
The reaction time is not a completely independent variable, but is dependent at least to some extent on the other reaction conditions employed, and the inherent reactivity of the reactants. In general, higher reaction temperatures require shorter reaction times. The process is usually complete in from about 0.5 to about 24 hours.
After the acylation has been conducted, it may be desirable to add water to the reaction mixture in order to hydrolyze any excess acid anhydride. The water addition may be accompanied by agitation of the reaction mixture (e.g. by stirring) to facilitate hydrolysis.
After any hydrolysis is conducted as discussed in the paragraph immediately above, the deacylation and desulfurization reaction can be conducted on the reaction mixture produced. In other words, it is not necessary to isolate compound (III) in order to conduct the next step. Although isolation is not necessary, it can be carried out if desired, using techniques within the skill of the art, e.g. fractional crystallization, distillation, extraction and the like.
The deacylation and desulfurization is generally conducted at a temperature which gives a reasonable rate of reaction, but which does not cause unwanted, extraneous side reactions to take place with loss of yield of desired product. For example, temperatures of from 50° to 100° C. can be employed; generally it is preferred to use a temperature of from 70°-90° C.
Ambient pressures are preferred; however, somewhat elevated pressures can be used if the reaction is to be conducted at a temperature above the boiling point of one or more of the constituents in the reaction mixture.
The deacylation/desulfurization is generally conducted using a hydrochloric acid or hydrobromic acid. In general, the amount of acid is at least stoichiometric; however, an excess of acid can be employed if desired. The amount of hypophosphorous acid (H 3 PO 2 ) employed is preferably at least equimolar with the thiadiazine. However, additional H 3 PO 2 can be used if desired.
The reaction time is not a truly independent variable, but is at least somewhat dependent on the reaction temperature and the inherent reactivity of the reactants. In general, reaction times of from 0.5 to 10 hours are sufficient.
After the desulfurization reaction is complete the desired pyrazolotriazole can be isolated from the reaction mixture by a known technique such as extraction, as indicated by the following examples.
EXAMPLE 1
6-Methyl-3-[1-(4-nitrophenoxy)tridecyl]-1H-pyrazolo-[5,1-c]-1,2,4-triazole
A mixture of 47.4 g (0.10 m) of 6-methyl-3-(1-[4-nitrophenoxy]tridecyl)-7H-1,2,4-triazolo[3,4-b]-[1,3,4]thiadiazine (1a) and 150 g of acetic anhydride is heated under reflux for 7 hours and left at room temperature over night. Acetic acid (30 g) is added and the mixture is heated to 60° C. A solution of 12.5 g of c-HCl (36%) in 15 ml of water is then added over 20 minutes to assure that hydrolysis of acetic anhydride is complete.
The mixture is cooled to 30° C. and there is added 50.8 g of c-HCl, 13.2 g of 50% hypophosphorous acid, and 56 ml of water. The mixture is slowly heated to 85° C. and stirred at that temperature for 3 hours. During the heating period a gentle gas evolution occurs. The gas is passed through a pre-scrubber solution made of caustic and sodium hypochlorite. The product is extracted with 210 ml of toluene at 65° C. and the toluene solution is washed with hot water (65° C.) 4-5 times to remove acids. While keeping the temperature at 65°-70° C., 230 ml of hot heptane (65° C.) is added and the mixture is cooled slowly without stirring to room temperature. The crystallized product is collected, washed well with 1:1 mixture of toluene and heptane, and dried to give 36.2 g (82%) of 6-methyl-3-[1-(4-nitrophenoxy)-tridecyl]-1H-pyrazolo-[5,1-c]-1,2,4-triazole(2a) with 98 area % by HPLC.
EXAMPLE 2
6-t-Butyl-3-(3nitro-2,4,6-trimethylphenyl)-1h-pyrazolo-[5,1-c]-1,2,4-triazole (2b)
With 6-t-butyl-3-(3-nitro-2,4,6-trimethylphenyl)-7H-1,2,4-triazolo-[3,4-b][1,3,4]thiadiazine (1b), the reaction is carried out as Example 1. After the reaction is complete, the reaction mixture is filtered while hot and drowned out into the water. The precipitated product is collected, washed well with water, and dried. It is slurried in 1:1 mixture of toluene and heptane, and dried again to give the product 2b in 78% yield with 98 area % by HPLC.
In the following example, all parts are by weight.
EXAMPLE 3
A suitable glass-lined reactor is purged with nitrogen to less than 8% oxygen. Thereafter 669 parts of 6-methyl-3-[1-(4-nitrophenoxy)-tridecyl]-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazine is charged to the reactor. Thereafter 238 parts of acetic anhydride is metered into the reactor. The agitator is started and the contents heated to 133° C. by using 140° C. steam applied on the jacket. The reaction mixture is maintained at 133° C. for 20 hours. Thereafter, the batch is cooled to 50° C. and sampled for completeness of reaction. If the reaction is complete (less than 2.0% of starting thiadiazine) the batch is cooled and pumped to a receiver or transferred directly to a second reactor.
Hydrochloric acid, 32%, 1690 parts, and 412 parts of 50% hypophosphorous acid are admixed in a reactor receiver. A solution of 100 parts of 32% hydrochloric acid and 1500 parts of filtered water is prepared in the second reactor and heated to 70° to 80° C. Two reaction batches prepared as above and containing the non-isolated 1-acetyl-7-acetylthio-6-methyl-3-(1-[4-nitrophenoxy]tridecyl)-1-H-pyrazolo(5,1-c)-1,2,4-triazole are cautiously transferred to the second reactor while maintaining the contents temperature at 70°-80° C. The hydrochloric acid/hypophosphorous acid solution in the receiver is charged to the second unit at such a rate as to maintain the batch at a temperature less than 80° C. The resultant reaction mixture is maintained at 75°-80° C. for an additional three hours by applying tempered water on the jacket.
Off gasses are vented to an appropriate scrubber. The resulting mixture is checked for completeness of reaction and cooled to 65° C.
If the reaction is complete 1500 parts of toluene is added to the reaction mixture while maintaining the temperature at 65°-70° C. The resultant mixture is settled and the bottom aqueous layer discarded. The toluene layer is washed once with water and twice with water containing 50 parts of sodium chloride. All washes contained 5000 parts of filtered water. During the washings the temperature is maintained at 65°-70° C.
To the washed toluene layer is added 4800 parts of heptane while maintaining the temperature at 70°-75° C. The resultant mixture is then seeded using 20 parts of 6-methyl-3-[1-(4-nitrophenoxy)-tridecyl]-1-H-pyrazole(5,1-c)-1,2,4-triazole. The resultant mixture is then cooled to 18°-22° C. and held at that temperature for 30 minutes.
The resultant mixture is then filtered and the product cake washed with heptane and toluene (1500 parts of each) and then dried and packaged in drums with clear plastic liners.
A suitable stainless steel or glass lined reactor is purged with nitrogen to less than 8% oxygen. Thereafter toluene, 4,040 parts is metered into the reactor and the agitator started. One entire batch of crude 6-methyl-3-[1-(4-nitrophenoxy)-tridecyl]-1-H-pyrazole(5,1-c)-1,2,4-triazole, approximately 900 parts, is charged to the reactor and the batch heated to 70°-75° C. using steam. The batch is maintained in that temperature range for one hour. An additional 4,040 parts of heptane is metered into the batch while maintaining the batch temperature at 70°-75° C. The resultant solution is then cooled to 69° C. and seeded using 20 parts of recrystallized 6-methyl-3-[1-(4-nitrophenoxy)-tridecyl]-1-H-pyrazole(5,1-c)-1,2,4-triazole. The batch is then cooled in a controlled manner to 18°-22° C. and held at 18°-22° C. for 30 minutes. The batch is filtered and the cakes are washed with a mixture of 1500 parts of heptane and 1500 parts of toluene. There is recovered recrystallized 6-methyl-3-[1-(4-nitrophenoxy)tridecyl]-1-H-pyrazole (5,1-c)-1,2,4-triazole.
The invention has been described above with particular reference to preferred embodiments thereof. A skilled practitioner, aware of the above detailed description can make many modifications or substitutions without departing from the scope or spirit of the following claims. | Pyrazolotriazoles such as 3,6-disubstituted-1H-pyrazolo[5,1-c]-1,2,4-triazoles: ##STR1## are useful in the photographic arts, e.g. as magenta couplers. They may be made from 3,6-disubstituted-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines: ##STR2## by a two-step process. The first step comprises a ring contraction and a diacylation. The second step comprises hydrolysis of the acyl groups and desulfurization. The second step is conducted using an aqueous mixture of a hydrohalic acid such as hydrochloric acid and hypophosphorous acid, H 3 PO 2 . When the hypophosphorous acid is used, less sulfur and sulfur-containing impurities are formed. | 2 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present U.S. Patent Application claims priority from earlier filed U.S. Provisional Patent Application Ser. No. 60/467,649 filed May 2, 2003 and entitled “Integrated Circuit For Task Light,” and Ser. No. 60/467,981 filed May 5, 2003 and entitled “Electrical Circuit For A Portable Fluorescent Task Lamp.”
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention generally relates to battery operated lamps and, more particularly, to battery operated fluorescent lamps having built-in battery recharging capability and operable from either a 120 VAC or 12 VDC source of power.
[0004] 2. Description of the Prior Art
[0005] Portable incandescent lamps, which operate by using an electric current to heat a filament, have been readily available for use as flashlights, task lights or work lights (e.g., ‘drop’ lights), camp lights, and the like. While generally reliable and reasonably durable, incandescent lamps are inefficient, whether operated from AC or DC voltage sources. Further, battery operated incandescent lamps are generally limited in the amount of light output because of the inefficiency of heated filament technology. Other disadvantages of incandescent lamps include the susceptibility of filaments to breakage and the heat produced, which can be uncomfortable when used in close quarters.
[0006] Portable fluorescent lamps have also been readily available for use as flashlights, task lights or work lights (e.g., ‘drop’ lights), camp lights, and the like. As is well known, fluorescent lamps are relatively efficient compared to incandescent lights, but they require a ballast device of some type to provide both a high starting voltage to ionize the gas within the bulb and a current-limiting impedance to limit the current flowing between the lamp terminals after the gas becomes ionized and highly conductive. In conventional AC operated fluorescent lamps the ballast device is a relatively large, heavy inductor in series with the fluorescent bulb. The large inductor provides a high back EMF when the alternating supply current reverses in the inductor, which causes a high starting voltage to ionize the gas within the bulb. The large inductance also provides a substantial impedance to the flow of current through the bulb after the ionization takes place.
[0007] In conventional portable fluorescent lamps, a small fluorescent bulb rated at, e.g., four watts, can be illuminated effectively with a battery voltage of 7.5 to 9.0 volts and a small step-up converter circuit to produce the relatively high starting voltage required. For such a low power rating, the inductance required to limit the current after ionization is correspondingly small enough to allow a practical battery operated fluorescent lamp that is not too bulky or heavy. However, fluorescent bulbs rated at four watts or even six watts do not provide much more light than a typical seven watt incandescent night light. Further, at 7.5 volts DC, the five large, C or D-cell alkaline batteries typically used in such lamps, which may provide up to one hour of illumination between battery replacement or recharging, causes the lamp to be bulky and heavy.
[0008] There are higher rated fluorescent bulbs available, such as a 13 watt Compact Fluorescent Lamp (CFL) Bi-Pin bulb. Such a bulb provides much higher light output but requires that more power be delivered by the ballast circuit. With conventional technology, this requirement demands a larger ballast circuit and further limits the battery life. While battery technology is continually improving, 13 watt, battery powered, portable fluorescent lamps, to be practical to use, must rely on rechargeable batteries. Typically, the lamp, in order to keep the size and weight within practical limits, contains only the batteries, the bulb, and an electronic ballast circuit. After a relatively short duration of use, typically one hour, the batteries must be replaced or recharged on an external battery charger A typical external battery charger may have substantial bulk and weight, especially if it operates from a standard wall outlet of 120 VAC. There is currently no known portable fluorescent lamp available that includes the batteries, ballast, and bulb that also includes a built-in AC-DC converter and battery charger in a compact, flashlight-sized, light-weight package.
[0009] What is needed is a higher efficiency, 13 watt portable fluorescent lamp that includes a built-in battery charger and operates off of either 120 VAC or 12 VDC power, yet is compact and light weight, i.e., approximately the size and weight of a conventional flashlight powered by two or three “D” cells. Further, the portable fluorescent lamp must be as easy to handle as a flashlight—i.e., have all the electronics and the battery pack housed in an enclosure approximately the same size as the handle portion of a conventional “D” cell flashlight having two cells. The design must accordingly produce very little heat so that it may be comfortably held by the handle that encloses the electronics. The handle must be small enough in diameter to hold easily and securely in the average-sized person's hand. Further, the battery charger built-in to the handle must be efficient enough to recharge the battery pack in under 90 minutes while the portable lamp is in use.
SUMMARY OF THE INVENTION
[0010] Accordingly, there is disclosed a 13 watt, battery operated, portable fluorescent lamp that is provided by the advancement in technology of the present invention. The lamp comprises a tubular housing configured as a handle grip portion at one end and a cylindrical lens portion at the other end. The tubular housing lockably connects to a compact battery pack. The cylindrical lens portion encloses a miniature, 13 watt fluorescent bulb. The electrical circuitry, enclosed within the handle grip and alternately operable from either 120 VAC or 12 VDC, includes a converter circuit, a battery charging circuit, and a fluorescent lamp ballast circuit. The compact battery pack is electrically coupled to the charger and ballast circuits and configured to simultaneously receive charging current from an output of the charging circuit and to deliver DC supply voltage to the fluorescent lamp ballast circuit during use of the lamp without the occurrence of a net discharge of the battery pack.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 illustrates a block diagram of one embodiment of a portable fluorescent lamp according to the present invention;
[0012] FIG. 2 illustrates an electrical schematic diagram of one embodiment of a converter circuit that may be used in the portable fluorescent lamp of FIG. 1 ;
[0013] FIG. 3 illustrates an electrical schematic diagram of one embodiment of a battery charging circuit that may be used in the portable fluorescent lamp of FIG. 1 ;
[0014] FIG. 4 illustrates an electrical schematic diagram of an embodiment of an electronic ballast circuit that may be used in the portable fluorescent lamp of FIG. 1 ;
[0015] FIG. 5 illustrates a pictorial view of one embodiment of a portable fluorescent lamp according to the present invention;
[0016] FIG. 6 illustrates an exploded pictorial view of one embodiment of a battery pack for use with the portable fluorescent lamp of FIG. 5 ;
[0017] FIG. 7 illustrates a pictorial view of an assembled battery pack for use with the portable fluorescent lamp of FIG. 5 ; and
[0018] FIG. 8 illustrates a partially cut-away pictorial view of the interior of the embodiment of the portable fluorescent lamp of FIG. 5 .
DETAILED DESCRIPTION OF THE INVENTION
[0019] Referring to FIG. 1 , there is illustrated a block diagram of one embodiment of the electrical circuitry for a portable fluorescent lamp 10 according to the present invention. The principal components of the electrical circuitry for the lamp 10 include a converter circuit 12 , a battery charger circuit 42 , a battery pack 52 , an electronic ballast circuit 62 , and a miniature fluorescent bulb 72 . The battery charger 42 may be operated from either a 120 VAC voltage source or a 12 VDC voltage source. The converter circuit 12 receives the 120 VAC via lines 14 , 16 , which may terminate in a receptacle (not shown) that mates with a matching plug of an AC line cord (not shown). The converter produces an output voltage of approximately 13 volts DC under load on lines 18 , 20 , which terminate at the terminals of one side of a DPDT switch 22 . When the wiper contacts of the switch 22 are in the “AC” position, the lines 18 , 20 are connected to the lines 24 , 26 , which connect to the +12 volt and the common (COM) input terminals respectively of the battery charger circuit 42 . Thus, in the “AC” position, the switch 22 couples the converter circuit 12 between the 120 VAC voltage source and the input to the battery charger circuit 42 .
[0020] Alternatively, the battery charger circuit may be operated directly by a 12 VDC voltage source via lines 28 , 30 , which may terminate in a receptacle (not shown) that would mate with a matching plug of a DC line cord (not shown), and connect to the terminals of the other side of the DPDT switch 22 . When the wiper contacts of the switch 22 are in the “DC” position, the lines 28 , 30 are connected to the lines 24 , 26 , which connect to the +12 volt and the common (COM) input terminals respectively of the battery charger circuit 42 . Thus, in the “DC” position, the switch 22 couples the lines 28 , 30 between the 12 VDC voltage source and the input to the battery charger circuit 42 . (Note: the 12 volt source rating is a nominal rating and may, in the case of an automotive battery, actually be in the range of 12.6 to 14.8 volts). A diode 32 , is inserted in series with the line 28 as a protective feature to prevent damage that may result from a reversed polarity DC voltage being applied to the electrical circuitry. The switch 22 is an optional feature. In some versions of the portable fluorescent lamp 10 , the lines 18 , 24 , and 28 are tied together and the lines 20 , 26 , and 30 are tied together. The control of which voltage source is used may then be determined by which line cord is connected between the voltage source and the portable fluorescent lamp 10 . Alternatively, the connections for an external 12 VDC source may be deleted, or, the connections for the 120 VAC source and the converter circuit itself may be deleted. Either alternate may be provided to accommodate particular product variations. It will also be appreciated that a portable fluorescent lamp having a built-in battery charger and battery pack in a small, light weight package is a combination not commonly found in the prior art.
[0021] Continuing with FIG. 1 , the battery charger circuit 42 produces a DC voltage suitable for charging the battery pack 52 . In the illustrative embodiment described herein, the output voltage is approximately 7.2 volts DC for charging a battery pack 52 containing six 1.2 volt, rechargeable nickel-metal-hydride (NiMH) cells. In the illustrated embodiment, the six NiMH cells are AA size, rated at 2200 milliAmpere-hours capacity, to provide sufficient power (approximately 15.8 watts) to drive a 13 watt miniature fluorescent lamp bulb to full brightness. This battery configuration was chosen for its compactness, and persons skilled in the art will appreciate that the portable fluorescent lamp 10 of the present invention operates with an efficiency exceeding 80%. The reasons for this high efficiency will become apparent in the detailed description which follows. It will also be understood that other battery configurations are certainly feasible and are contemplated for other similar applications. In the illustrated embodiment, the 7.2 volts output voltage is applied to the lines 44 , 46 , which couple the output of the battery charger circuit 42 to the battery pack 52 via terminals 48 , 50 for charging the battery pack 52 , and to the input terminals of the electronic ballast circuit 62 . A switch 54 , connected in series with the line 44 , functions as an ON-OFF switch for the portable fluorescent lamp 10 . The terminals 48 , 50 may be separate contacts located on the housing (not shown in FIG. 1 ) of the portable fluorescent lamp 10 or they may be incorporated into a connector mounted on the housing of the portable fluorescent lamp 10 .
[0022] Continuing with FIG. 1 , it is appreciated that the electronic ballast circuit 62 operates on the same voltage, in this case approximately 7.2 volts, that is applied to the battery pack 52 . The fluorescent ballast circuit produces a high voltage waveform output of approximately 400 Volts AC and approximately 30 KHz for “starting” the fluorescent bulb 72 via lines 64 , 66 , which couple to terminals 68 , 70 . The fluorescent bulb 72 is plugged into the terminals 68 , 70 . After ionization of the gas within the envelope of the fluorescent bulb 72 , the electronic ballast circuit 62 limits the current flowing through the fluorescent bulb 72 . In an optional feature, a pair of normally open (NO) contacts 74 , 76 are connected, via lines 80 , 82 , in series with the positive voltage line 44 from the battery pack 52 or the battery charger circuit 42 , as will be described herein below. The contacts 74 , 76 are closed whenever a fluorescent bulb 72 is plugged into the terminals 68 , 70 by the action of the barrier 78 on the pin base of the fluorescent bulb 72 . The terminals 68 , 70 may be part of a receptacle connector. These contacts provide a safety feature that limits access to the high voltage that may be present at the terminals 68 , 70 , when a bulb 72 is not plugged into the terminals 68 , 70 .
[0023] Referring to FIG. 2 , there is illustrated an electrical schematic diagram of one embodiment of a converter circuit 100 that may be used in the portable fluorescent lamp of FIG. 1 . The converter circuit 100 is configured as a feed forward converter that operates at approximately 50 KHz. and provides a DC output voltage of approximately 13 (+/−1) Volts under load from an input of 120 VAC at 50/60 Hz. The converter converts the low frequency 120 VAC input voltage to a high frequency AC voltage, steps down the AC voltage to a low voltage in the transformer 116 , and then rectifies and filters the low voltage to produce the low voltage DC output. The circuit is very efficient because the circuit losses are much smaller at the higher frequency. In FIG. 2 , the 120 VAC input is applied to input terminals 102 , 104 to a bridge rectifier 106 . A series resistor 108 between terminal 102 and the bridge rectifier 106 acts as a fuse. The rectified DC output voltage appears at a positive node 110 and a negative node 112 which is also the return node. A filter capacitor 114 is connected across the DC output at nodes 110 , 112 . This rectifier circuit supplies approximately 170 VDC to the rest of the converter circuit to be described.
[0024] The 170 VDC output of the rectifier is applied across a primary winding 118 of an isolation transformer 116 and a transistor switch 126 in series. In the illustrative embodiment, the transistor switch 126 is a type IRF740 N-channel MOSFET rated at 400 Volts, 6.3 Amps, and having an Rds(on) of <0.55 Ohms. This device is available from STMicroelectronics. One side of the primary winding 118 having the polarity symbol (a dot) is connected to node 110 , the positive output of the rectifier bridge 106 . The other side of the primary winding 118 , at node 124 , is connected to the drain terminal of the transistor switch 126 . The source terminal of the transistor switch 126 is connected to the return node 112 . During operation, the transistor switch 126 is turned on and off at a 50 KHz rate, which periodically charges the primary winding 118 with a pulse of current to produce a 170 Volt peak-to-peak square wave. According to the turns ratio of the transformer 116 , a smaller, stepped-down replica of the pulse waveform produced across the primary 118 of transformer 116 appears across the secondary winding 122 of transformer 116 . The transistor switch 126 is caused to turn on and off by a pulse control signal applied to the gate terminal of the transistor switch 126 that is supplied from the “Q” output at pin 3 of an integrated circuit timer (timer IC) 140 operated as an a-stable multivibrator or oscillator. The timer IC 140 used in the disclosed embodiment is a standard 555 type timer IC available from a variety of manufacturers. The control signal has a duty cycle of approximately 50%. In the description which follows, the term “integrated circuit” may be abbreviated as “IC.”
[0025] Operating voltage Vcc for the timer IC 140 is applied to pin 8 . Pin 4 of the timer IC 140 is also connected to pin 8 . The operating voltage at pin 8 is produced by a dropping resistor 150 and a 12 Volt zener diode 152 connected in series across the 170 VDC output of the rectifier at nodes 110 , 112 . Capacitor 154 provides some high frequency filtering of the DC voltage supplied by the action of zener diode 152 . This simple power supply provides the starting voltage for operating timer IC 140 . At other times, the operating voltage for timer IC 140 (Vcc) is provided by a rectified output from a secondary winding 120 of transformer 116 connected between node 156 and the common node 112 . The voltage across the secondary winding 120 is rectified by diode 158 , filtered by capacitor 154 , and applied to pin 8 of the timer IC. The frequency of the a-stable oscillator is set by resistor 142 and capacitor 144 . Resistor 142 is connected between pin 3 of the timer IC 140 and pins 2 and 6 of the timer IC 140 tied together. Capacitor 144 is connected between pin 6 of the timer IC 140 and the common terminal 112 . A bypass capacitor is connected between pin 5 of the timer IC 140 and the common terminal 112 .
[0026] Continuing with FIG. 2 , the low voltage output across the secondary winding 122 at nodes 170 , 176 of transformer 116 is rectified by rectifier 172 connected in series with the node 170 of the secondary winding 122 . The rectified output voltage is filtered by capacitor 178 connected between a positive node 174 and a negative (common) node 180 . The node 180 is connected to the node 176 of the secondary winding 122 . Persons skilled in the art will appreciate that the DC output voltage of the converter 100 is unregulated, and thus subject to variation as the AC input voltage varies. However, the regulation of the actual DC charging voltage applied to the battery pack during charging is regulated by another part of the electrical circuitry in the portable fluorescent lamp 10 .
[0027] Referring to FIG. 3 , there is illustrated an electrical schematic diagram of one embodiment of a battery charging circuit that may be used in the portable fluorescent lamp of FIG. 1 . The battery charging circuit 200 is essentially a DC-to-DC switching regulator controlled by a battery charging controller IC 210 responsive to a feedback signal from the DC voltage output. The switching regulator is driven by an a-stable timer IC oscillator 260 operating at 50 KHz, similar to that used in the converter circuit 100 described herein above. The output of the oscillator applied to the gate of an N-channel FET is gated by a logic circuit 280 controlled by the battery charging controller. The battery charging circuit 200 in the illustrative embodiment of FIG. 3 operates from a 12 to 14 VDC input and provides an output voltage of approximately 7.2 Volts while delivering a charging current of up to approximately 1.5 Amperes to the battery pack 52 or FIG. 1 . The input voltage may be supplied from a converter operating from a 120 VAC voltage source as illustrated in FIG. 2 or from a 12 to 14 Volt battery such as an automotive battery.
[0028] The 12 VDC input is applied across the positive terminal 202 and the negative (common) terminal 204 , which correspond respectively to nodes 206 , 208 . Connected in series between node 206 and a positive output terminal 222 are, in order, a P-channel MOSFET transistor switch 250 , a rectifier diode 252 , node 254 , and inductor 256 . The transistor switch 250 in the illustrative embodiment is a type FQB11P06 P-channel MOSFET rated at −60 Volts, −8.05 Amps, and having an Rds(on) of <0.175 Ohms. This device is available from Fairchild Semiconductor. Node 206 is connected to the source terminal of the transistor switch 250 . The anode of diode 252 is connected to the drain terminal of transistor switch 250 and the cathode of the diode 252 is connected to node 254 . The negative (common) output terminal 224 is connected to node 208 . Another rectifier diode is connected between node 254 (cathode) and node 208 (anode). The three integrated circuits of FIGS. 3 , 210 , 260 , and 280 , are each connected between node 206 , the Vcc supply, and node 208 , the Vss common terminal.
[0029] Continuing with FIG. 3 , the circuit of the battery charging controller 210 , will now be described. The battery charging controller IC 210 , in the illustrative embodiment, is a type bq2002C, a “NiCd/NiMH Fast-Charge Management IC” manufactured by Unitrode Corporation, a subsidiary of Texas Instruments, Dallas, Tex. In FIG. 3 , a resistor 212 is connected between node 206 and pin 6 (the Vcc terminal) of the battery charging controller IC 210 . Pin 5 (a temperature sense input) of controller IC 210 is connected to pin 6 of controller IC 210 . Connected between pin 6 of controller IC 210 and node 208 are a 5.1 Volt zener diode 214 , a bypass capacitor 216 and a first resistor 218 in series with a second resistor 220 . The zener diode 214 sets the Vcc voltage for controller IC 210 at 5.1 Volts DC. The junction between the two resistors 218 , 220 , which form a resistive voltage divider, is connected to pin 1 of controller IC 210 to set the operating mode of the battery charging controller IC 210 (“charge timer, top-off, voltage termination mode, trickle rate,” etc.). Pin 7 (the Vss terminal) of controller IC 210 is connected to the common node 208 .
[0030] Also connected between pin 6 of controller IC 210 and node 208 is a network of light emitting diodes (LEDs) including resistor 232 , LED 234 , LED 236 and resistor 238 , all connected in series. The junction of LEDs 234 and 236 is connected to pin 2 of controller IC 210 . Pin 2 is the charging status output, which indicates whether the battery is being charged at a fast charge rate (steady red LED 234 ), or at a trickle rate (blinking red LED 234 ) or that the battery is fully charged (steady green LED 236 ). Pin 3 of controller IC 210 , the battery voltage input, is connected through a resistor 226 to the positive output terminal 222 . A resistor 228 and a bypass capacitor 230 are connected in parallel between pin 3 of controller IC 210 and the common node 208 . Bypass capacitor 230 prevents the termination of charging on noise that may be present on the output terminal 222 . Pin 8 of controller IC 210 , the charge control output terminal, is connected to a node 240 . A pull-up resistor 242 is connected between node 240 and node 206 . The output signal at pin 8 of controller IC 210 is a logic high for fast charging, pulsed for trickle charging, and logic low when charging is not occurring.
[0031] Timing for the switching regulator circuit of the battery charging circuit 200 is provided by timer IC 260 , a type 555 timer IC available from a variety of manufacturers. Vcc pin 8 of timer IC 260 is connected to node 206 and also to the Reset pin of timer IC 4 of U 3 260 . Vss pin 1 of timer IC 260 is connected to the common node 208 . Timing resistor 262 is connected between the Q output pin 3 of U 3 260 and the TR pin 2 of timer IC 260 , which is also tied to the CV pin 6 of timer IC 260 . The timing capacitor 264 is connected between pins 2 , 6 of timer IC 260 and the common node 208 . Pin 5 of timer IC 260 is connected to the common node by capacitor 266 . The timer IC 260 , connected as an a-stable oscillator, provides a 50 KHz, 50% duty cycle pulse train at pin 3 for driving the transistor switch 250 .
[0032] The pulse train signal from pin 3 of the timer IC 260 is gated to the transistor switch 250 by logic circuit 280 under the control of the charge control output from pin 3 of the battery charging controller IC 210 . The logic circuit 280 may be a four stage NAND gate IC such as a type CD4093, which is available from a variety of manufacturers. Two stages of logic circuit 280 , NAND gates 282 and 284 , are connected in series with their inputs (respectively 1, 2 and 12, 13) tied together and the input (pins 1 , 2 ) of NAND gate 282 tied to the output (pin 11 ) of NAND gate 284 . This configuration provides an inverter/driver for the pulse train signal for the transistor switch 250 . The output of NAND gate 282 at pin 3 is coupled to one input, pin 6 , of NAND gate 286 of logic circuit 280 , and also to pins 8 , 9 of NAND gate 288 of logic circuit 280 , whose output pin 10 is left floating. The other input of NAND gate 286 at pin 5 of logic circuit 280 is connected to the node 240 , which is the charge control output of the battery charging controller IC 210 . Thus, a logic high signal at node 240 (logic circuit 280 pin 5 ) enables the pulse train signal from NAND gate 282 at pin 3 to be coupled to the gate of the transistor switch 250 .
[0033] Under the control of the 50 KHz, 50% duty cycle pulse train applied to the gate terminal of the transistor switch 250 , the transistor switch 250 turns ON, and charging current flows through diode 252 and inductor 256 into the positive terminal of the battery pack connected to the positive output terminal 22 (see the battery pack 52 in FIG. 1 ). Also during this period, the charging current charges the inductor 256 , building a magnetic field around the inductor 256 . In the next period of the pulse train signal, the transistor switch 250 turns OFF, and current ceases to flow through diode 252 . At this instant, the magnetic field surrounding the inductor 256 collapses, causing current to flow in the opposite direction through the inductor 256 . At this time, the diode 258 is forward biased and the inductor delivers charging current through the diode 258 and into the negative terminal of the battery being charged, which is connected to the negative terminal of the battery charging circuit 200 . In this way, charging current is delivered to the battery pack during both periods of the pulse train signal, when the transistor switch 250 is alternately in its ON and OFF states. Thus, the battery charging circuit 200 is operating “full time” to charge the battery pack.
[0034] Continuing with FIG. 3 , a modification may be made to the battery charging circuit if it is intended to operate from an external DC power source such as a automotive storage battery the typically supplies 12.6 to 14.8 volts, depending on the state of charge and the load connected to the battery. The aforementioned battery voltage available is somewhat lower than the voltage provided by the converter circuit of FIG. 2 . The modification, which provides a way to increase the duty cycle of the switching regulator, consists of connecting resistor 262 to the Vcc terminal, pin 8 of the timer IC 260 instead of to pin 3 of the timer IC 260 , and adding a resistor from the junction of the resistor 262 and capacitor 264 to pin 7 of the timer IC 260 . The value for this additional resistor is selected according to the duty cycle that is desired—the ratio of resistor 262 to the added resistor determines the duty cycle.
[0035] Referring to FIG. 4 , there is illustrated an electrical schematic diagram of one embodiment of an electronic ballast circuit 300 that may be used in the portable fluorescent lamp of FIG. 1 . The ballast circuit 300 converts the 7.2 volts DC, supplied by battery pack 52 to the positive input terminal 302 and negative (common) input terminal 304 , to a high frequency, high voltage AC signal. This high voltage signal, a 30 KHz square wave having a peak-to-peak amplitude of approximately 400 volts, is applied to the fluorescent bulb 370 to ionize the gas within the fluorescent bulb 370 . The ballast circuit 300 includes a current limiting feature to limit the current in the bulb after the gas is ionized and the fluorescent bulb 370 begins producing light.
[0036] Connected between the positive input terminal 302 and a node 306 is a series-connected SPST switch 308 that is used to turn the fluorescent lamp ON and OFF. Switch 308 applies power to the ballast circuit 300 . The negative input terminal is connected to a common node 310 . A transformer 312 is configured to provide operating currents to a two-transistor, a-stable multivibrator or oscillator circuit and to step up the oscillator output voltage square wave to a value needed to start the ionization of the gas within the fluorescent bulb 370 . Transformer 312 includes a center tapped primary winding 314 A- 314 B, which is connected between nodes 316 and 318 . Node 316 connects to the collector of bipolar transistor 330 , which forms one side of the multivibrator circuit. Node 318 connects to the collector of an identical bipolar transistor 332 , which forms the other side of the multivibrator circuit. A capacitor 320 , which, in part, determines the operating frequency of oscillation of the a-stable multivibrator circuit, is connected between the nodes 316 and 318 . The center tap of the primary winding 314 A- 314 B, defined as node 322 , is connected through an inductor to node 306 . This inductor acts to prevent current spikes from the multivibrator when the transistors change states.
[0037] Continuing with FIG. 4 , a second primary winding 334 of transformer 312 is connected between nodes 336 and 338 . Nodes 336 and 338 connect to the supply voltage at node 306 through resistors 340 and 342 respectively. Nodes 336 and 338 provide bias current into the base terminals of transistors 330 and 332 , respectively. The emitters of the bipolar transistors 330 and 332 are connected to the common node 310 . Transistors 330 and 332 , which are type KSD 1691G available from Fairchild Semiconductors, are chosen for their very high gain, hfe, and very low saturation voltage, Vsat. As is well known in the art, when voltage is applied to the input terminals 302 , 304 of the multivibrator circuit, the imbalance between the two transistors' characteristics causes one of them to conduct current more quickly than the other, thus starting the oscillations of the a-stable multivibrator.
[0038] The output of the multivibrator 330 , 332 is taken from the secondary winding 350 of transformer 312 . The output signal is essentially a square wave having a frequency of approximately 30 KHz and a duty cycle of approximately 50%. The amplitude of the signal across the secondary winding 350 isapproximately 400 volts peakto peak. One leg of the secondary winding is connected via a series capacitor 352 to a node 354 . The other leg of the secondary winding 350 is connected to a node 356 , which is also connected to the common node 310 . Nodes 354 and 356 are respectively connectedto the terminals 358 , 360 of the receptacle for the bi-pin fluorescentbulb 370 . The fluorescent bulb 370 includes a base 372 containing the bi-pin terminals that plug into the receptacle terminals 358 , 360 .
[0039] It is well known that once the gas within a fluorescent bulb has become ionized, the bulb presents a negative impedance characteristic to the external circuitry connected to the terminals of the bulb. That is, once the bulb begins to conduct, the current will continue to increase without bound until the bulb is destroyed unless the current is limited to a safe value. In a conventional fluorescent lamp that is controlled by a conventional ballast, the ballast provides a large inductive impedance to the alternating current flowing in the lamp. In the illustrative ballast circuit of the present invention, the transformer 312 is designed with an air gap in the core so that a substantial inductive impedance appears in series with the current flowing in the secondary winding 350 and the fluorescent bulb 370 .
[0040] Referring to FIG. 5 , there is illustrated a pictorial drawing of one embodiment of a portable fluorescent lamp 400 according to the present invention. The portable fluorescent lamp 400 includes a tubular housing 432 having a handle grip (or body) portion 402 at the lower end and a cylindrical lens portion 404 at the upper end. The cylindrical lens portion may be fabricated of a material that readily transmits light, and may further be configured to transmit light in all directions—i.e., 360 degrees-surrounding the longitudinal axis of the cylindrical lens portion 404 . Enclosed within the cylindrical lens portion 404 is a bi-pin fluorescent bulb 406 that is plugged into a receptacle base 408 inside the cylindrical lens portion 404 . Along the back side of the cylindrical lens portion 404 is a tubular spine 410 , which mechanically connects the handle grip portion 402 , the cylindrical lens portion 404 and an end cap 412 together. The tubular spine, which may have a somewhat flattened oval or rectangular cross-section, strengthens the structure of the portable fluorescent lamp 400 assembly to prevent breakage if the lamp 400 is dropped. The spine 410 serves to provide the additional stiffness to the lamp 400 , which is required because of the 8 to 10 degree offset of the cylindrical lens portion 404 relative to the handle grip portion 402 of the lamp 400 . The offset is built in to the tubular housing 432 so that when the lamp 400 is stood on its battery pack 500 , which serves as a base, the illumination from the lamp is directed downward toward the work surface. The tubular spine also provides space for circuitry to accommodate additional features such as a flashing light circuit, a circuit to drive indicator lights showing the status of the electrical circuitry and/or the batteries, etc.
[0041] The battery pack 500 , which will be described in detail herein below, is secured to the lamp 400 by a pair of opposing mandible jaws, of which the jaw release button 506 of one of the mandible jaws is shown in FIG. 5 . As the battery pack is brought into position against the bottom of the handle grip portion 402 , the jaws, having some built-in resilience to allow bending from a rest position, are inserted into slots in the handle grip portion 402 and snapped into place. The resilience is a property of the plastic material used to fabricate the handle grip portion 402 and the housing of the battery pack 500 .
[0042] It will be appreciated that the battery pack 500 , when attached to the tubular housing 432 acts as a substantial base for the portable fluorescent lamp 400 , because of its mass (due to the batteries) and because the bottom of the battery pack 400 may be flat to provide a stable base. Alternatively, the bottom of the base may also be configured as a dual-plane surface. In this case, the bottom surface may comprise two separate planes, joined at a central location on the bottom surface, and which differed angularly from each other, enabling the lamp 400 to be positioned upright at two different angles. For example, one angle could be set slightly downward for greater illumination near the lamp and the other angle, which differed by only 5 to 10 degrees or so, would be useful for illuminating broader areas. Persons skilled in the art will further realize that the angle of illumination may be varied in other ways, such as incorporating a pivot, e.g., near the midpoint of the structure of the portable fluorescent lamp. Also shown in FIG. 5 along the back of the handle grip portion 402 is a receptacle 424 for an AC line cord (not shown) to be used when operating the lamp 400 from an AC voltage source.
[0043] In an alternate embodiment not illustrated in FIG. 5 , a receptacle for connecting a power cord to connect the lamp 400 to a DC voltage source such as an automotive battery supply may be included on the handle grip portion 402 of the tubular housing. It is feature of the portable fluorescent lamp 400 of the present invention that the inclusion of a battery charging circuit operative from a nominal 12 VDC supply enables the lamp 400 to be operated from a 12 VDC source as readily as from a 120 VAC source. The selection of voltage source, 120 VAC or 12 VDC, the selection may be made by merely changing the AC line cord or the DC power cord, or by an extra switch is described in conjunction with FIG. 1 , which may be installed on the handle grip portion 402 of the tubular housing 432 .
[0044] Referring to FIG. 6 , there is illustrated an exploded pictorial view of one embodiment of a battery pack 500 for use with the portable fluorescent lamp of FIG. 5 . The battery pack 500 , fabricated of molded plastic material, includes a bottom pan 502 having a pair of opposing mandible jaws 504 (“jaws 504 ”) molded integral with the bottom pan 502 and on opposite sides of the base 502 . The jaws 504 are oriented in a vertical direction, perpendicular to the bottom pan 502 and configured such that they are resilient when bent during installation or removal of the battery pack 500 onto or from the tubular housing 432 of the portable fluorescent lamp 400 of FIG. 5 . The outer surface of the jaws 504 include a ridged button 506 for use in deflecting the jaws 504 to remove the battery pack 500 from the portable fluorescent lamp 400 as will be described further herein below.
[0045] The bottom pan 502 of the battery pack 500 is further configured to receive a plurality of batteries assembled as a cell pack 510 . Disposed above the cell pack 510 is a retainer plate 512 for securing and positioning a pair of battery terminals 514 . The terminals 514 are installed in recesses 516 molded into the retainer plate 512 . One terminal 514 may be designated a positive terminal and connected to the positive terminal of the cell pack 510 and the other would be designated a negative terminal 514 to be connected to the negative terminal of the cell pack 510 .
[0046] The battery pack 500 further includes a top cover 520 that includes a docking plate 530 , wherein the top cover fits over and encloses the cell pack 510 and retainer plate 512 when installed and secured to the bottom pan 502 using the resilient locking tabs 522 disposed near each corner of the bottom pan 502 . The top cover 520 includes openings 524 disposed on two opposite sides of the top cover 520 through which pass the opposing mandible jaws 504 . The top cover 520 also includes two contact openings 526 disposed in the docking plate 530 to expose and permit access to the positive and negative terminals 514 connected to the cell pack 510 . The contact openings 526 function to locate the positive and negative terminals 514 such that they make contact with corresponding terminals in the lower end of the handle grip portion of the tubular housing 432 containing the electrical circuitry when the battery pack 500 is assembled to the tubular housing 432 of the portable fluorescent lamp 400 .
[0047] Referring to FIG. 7 , there is illustrated a pictorial view of an assembled battery pack for use with the portable fluorescent lamp of FIG. 6 . The reference numbers for the figure are the same as those of FIG. 6 (or a lower numbered figure) and they refer to the same structures. The battery pack includes a bottom pan 502 assembled to a top cover 520 with the pair of opposing mandible jaws 504 protruding through the openings 524 in the top cover 520 , and exposing the ridged buttons 506 to view. The ridged buttons 506 , disposed on opposite sides of the battery pack 500 , are pressed toward each other to release the opposing mandible jaws 504 from corresponding jaw catches (not shown) inside the lower end of the handle grip portion 402 of the tubular housing 432 . In FIG. 7 , the assembled battery pack 500 further illustrates the docking plate 530 having the contact openings 526 and the positive and negative terminals 514 of the cell pack 510 visible therethrough.
[0048] Referring to FIG. 8 , there is illustrated a partially cut-away pictorial view of the interior of the embodiment of the portable fluorescent lamp of FIG. 5 . The illustration depicts a half shell 600 of the tubular housing 432 of the portable fluorescent lamp 400 of FIG. 5 , and includes one half of the handle grip portion 402 , the lens portion 404 , the fluorescent bulb 406 , the receptacle 408 for the fluorescent bulb, the tubular spine 410 , and the end cap 412 . The space above the lens portion 404 but within the end cap 412 is designated as reference number 414 . This space is available for additional features of the lamp 400 , which may include, for example, individual light indicators, spotlights or flashing lights, a hook for hanging the lamp 400 , a switch for an added electrical function, a magnet for supporting the lamp 400 , and the like.
[0049] Further, the cut-away view of FIG. 8 illustrates one arrangement of substrates such as printed circuit boards for the electrical circuitry (See FIGS. 1-4 ) used in the illustrative embodiment. For example, a first circuit board 602 may contain and support the circuits of FIGS. 2 and 4 , the 120 VAC converter and fluorescent ballast circuits respectively. Similarly, a second circuit board 604 may contain and support the battery charging circuit of FIG. 3 . Other configurations are certainly possible, depending upon the particular architecture of the portable fluorescent lamp 400 of the present invention. Also shown in FIG. 8 are the receptacle 424 for the AC line cord (not shown) and the ON/OFF switch 426 for the lamp 400 . The receptacle 424 and the switch 426 and a battery pack terminal 428 are also shown in FIG. 5 .
[0050] While the invention has been shown in only one of its forms, it is not thus limited but is susceptible to various changes and modifications without departing from the spirit thereof. For example, the compact, efficient architecture of the portable, rechargeable fluorescent lamp 400 disclosed herein is readily adaptable to higher power fluorescent bulbs with relatively little increases in size and weight of the end product. Further, the lamp design permits use with interchangeable battery packs and/or battery chargers. Moreover, as described previously, the lamp may be configured for operation from both AC and DC power sources, or from either one alone. In an AC operated lamp, the AC line cord may be replaced with an AC line plug designed to fit a standard 120 VAC wall outlet. In this configuration the portable fluorescent lamp 400 of the present invention may then be used as a power failure emergency light that would remain fully charged and provide auxiliary lighting, either while plugged in to the outlet or while carried around as a portable lamp.
[0051] Additional features may be included or modifications made in designs adapted to specific needs. As examples, the cylindrical lens portion 404 may be transparent or translucent. Translucent versions may be colored white or any of several other colors according to particular uses contemplated for the portable fluorescent lamp 400 . In an alternative embodiment, the cylindrical lens portion 404 may be configured to be interchangeable so that different colors or illumination properties may be conveniently provided. In yet other embodiments, the lens portion 404 may have cross-sections other than cylindrical, being, for example, square or rectangular, pentagonal or hexagonal, and so on. Reflectors may be incorporated within or outside the lens portion 404 to direct the light from the fluorescent bulb in predetermined directions or to shape or focus the light in particular predetermined ways. Such reflectors may further be interchangeable.
[0052] It is further contemplated that the handle grip portion 402 may have other shapes or other surface finishes to permit other kinds of gripping features than the illustrative embodiment described herein above. The handle grip portion 402 or other parts of the tubular housing 432 may include eyelets to enable supporting the portable fluorescent lamp from a lanyard or hook or other tether device. Certain applications may include structural features to make the tubular housing 432 gas tight or water tight and/or to incorporate other features such as buoyant means to enable the portable fluorescent lamp 400 to float in water or to be used while immersed, as in marine applications. The tubular spine 410 , being hollow, includes space for additional circuitry or for relocating the electrical circuitry from the handle grip portion 402 of the tubular housing 432 . In the latter case, the batteries may then be located in the handle grip portion of the lamp, enabling a reduction in the size of the lamp. The implementation of all such features and modifications are well within the skills of persons skilled in the art, as will readily be appreciated. | A battery operated fluorescent lamp is disclosed, which is operable from the battery while the battery is being recharged, comprising a tubular housing configured as a handle grip at one end and a cylindrical lens portion at the other end. The tubular housing lockably connects to a battery pack. The cylindrical 3030 lens portion encloses a miniature fluorescent bulb. The electrical circuitry, enclosed within the handle grip and alternately operable from either 120 VAC or 12 VDC, includes a converter circuit, a battery charging circuit, and a fluorescent lamp ballast circuit. The battery pack is electrically coupled to simultaneously receive charging current from an output of the charging circuit and to deliver DC supply voltage to the fluorescent lamp ballast circuit without the occurrence of a net discharge of the battery pack. | 5 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to a device for optimizing the speed control of a subfractional horsepower motor such as those typically used in dental instruments.
2. Description of the Prior Art
Two conventional control devices of this type are known in the art and disclosed in DE 32 21 146. In one of these designs, the regulation of the speed is accomplished through compensation of the internal voltage drop of the motor. The motor current is measured dependent on the motor load. Given a reduction in speed as a result of a higher load, a higher motor current is measured. Conversely, the speed increases with a reduction in load, and consequently a lower motor current is measured. The measured difference in motor current is fed to a controller that adjusts the speed to the desired value. An advantage of this type of motor regulation is extremely quiet operation of the motor even into its upper speed range. One disadvantage however, is that the motor provides relatively low torque, especially in its lowest speed range. The increases in current are too slight to compensate by measurement; in contrast thereto, the collector losses are felt to a relatively large degree.
In the second conventional control device, the speed is calculated by measuring the voltage with the motor switched off. One advantage of this design is that it provides extremely good torque for the motor, even in its lowest speed range. The regulation can compensate the collector losses well, and as a result speeds having high torque can be regulated down to zero. One disadvantage of this control method is that rough running that can lead to vibration may occur under certain circumstances in the upper speed range. The reason for this is that system-deactivation of the motor is necessary for the voltage measurement.
One object of the present invention is thus to provide a device that makes it possible to operate a subfractional horsepower motor of the type primarily used for dental equipment in such a way that it can be optimally controlled in every desired speed range. The device will provide optimum speed control even with different load values in both the lower as well as the upper speed range.
SUMMARY OF THE INVENTION
The present invention is based on a system which embodies the two aforementioned control devices and which processes each measurement. The device which is set forth in greater detail below can, preferably automatically, undertake a sliding transition from the voltage control into the current-load control and vice versa on the basis of predetermined motor data. The decision as to when the user must switch between two types of regulation is thus eliminated. The motor data required for the input, i.e. the switching speed on the one hand and the maximum speed at which the motor is to be operated, can either be permanently prescribed or can be set by the user.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a circuit block diagram of a first embodiment of the present invention;
FIG. 2 is a graph illustrating operation of the present invention;
FIG. 3 is a block diagram of a second embodiment of the present invention;
FIG. 4 is a graph illustrating operation of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A first exemplary embodiment of the present invention is set forth in FIG. 1. An electric motor 1 is driven by an output stage 2 that converts data from a control and regulation computer 3 into motor speed and motor torque. The computer 3 contains a current-load module 4 and voltage module 5. The current-load module 4 processes the incoming motor data according to the initially described current-load compensation method. The voltage module 5 processes the incoming motor data according to the voltage measurement. The motor control module 6 is connected to the motor output stage 2 and drives the output stage according to either the current-load control method or according to the voltage control method.
The motor speed data required for voltage measurement is input into the computer via the line 7. Information for the current load compensation, which is obtained in a known way via a resistor 9, is input into the computer 3 via the line 8. Corresponding control information is also forwarded by the computer 3 to a current shut-off circuit 10 required for the voltage measurement.
An evaluation logic circuit 11 decides whether voltage or current load control is to be used. The information required for the decision is supplied by comparison logic 12 into which information about the desired, maximum speed is input via input 13. Information about the selected switching speed U at which the change is to be made from voltage control to current load control is input via an additional input 14. Comparison logic 12 decides whether the current speed, i.e. the actual speed, is higher or lower than the switching speed U and forwards the result to evaluation logic 11. The input of the switching speed U can be input by the operator at a panel or in some other manner. The same is true of the desired, maximum speed at which the motor is to be operated.
The switching event is set forth with reference to the diagram of FIG. 2. The switching speed U at which a switch is undertaken from voltage to current-load control and vice versa can be defined by the user. For example, this switching value should be at a rated value of 2,000 rpm. When the maximum speed N1max is above the switching speed U, for example at 40,000 rpm, then regulation ensues according to current-load compensation. When, in contrast, the maximum speed N2max lies below this value, for example at 800 rpm, then speed regulation is accomplished only with voltage measurement. The switching speed U can be advantageously set by the individual user. It is desirable, however, to permanently set this at the time of installation of a dental apparatus wherein the subfractional horsepower motor is utilized. The maximum desired speed can be automatically called in during the treatment or can also be manually input. When the desired speed is above the switching speed U, the current-load compensation is used for the entire, selected speed range. When, in contrast, procedures are to be carried out that require a speed in the lower speed range, then the user will select a maximum speed below the switching speed U. The voltage control is automatically activated for this selection, this resulting therein that the motor 1 outputs a relatively high torque even in the lower speed range.
FIG. 3 shows an embodiment wherein the adaptation to the two types of control or regulation ensues automatically. In contrast to the above-described exemplary embodiment, it is not the switching speed U but a switching range that is input via input 14 of comparison logic 12. The comparison logic 12 compares whether the current speed that is likewise input into the comparison logic 12 via the line 7 is above, below or within the switching range. When the current motor speed lies in the switching range, the evaluation logic 11 decides how many switching parts or, respectively, regulating parts should take effect. This information is supplied to the computer 3 that then selects either the current load module 4 or the voltage module 5 or corresponding portions of the two modules for control characteristics. Viewing the diagram of FIG. 4, it may be seen that all the more current load control parts must be activated the closer the current motor speed comes to the switching speed U. At the same time the voltage influences are slowly eliminated. When the speed in turn drops, the proportions shift in the opposite direction. When the electronics is in the current load range, the speed is only rarely measured, so that the motor exhibits extremely quiet running. In contrast, when the speed again approaches the transition range, the voltage regulation starts to become active. Below the transition range, only the voltage regulation takes effect. The interruption of the motor current for the speed measurement required in this lower speed range, however is unnoticeable in this speed range.
The present invention is subject to many variations modifications and changes in detail. It is intended that all matter described throughout the specification and shown in the accompanying drawings be considered illustrative only. Accordingly, it is intended that the invention be limited only by the spirit and scope of the appended claims. | A device for the optimizing of the speed control of an electric subfractional horsepower motor for dental instruments is provided wherein it is possible to operate the motor in any desired speed range. The device contains a first module for regulating the speed by voltage measurement, a second module for regulating the speed by current-load compensation, and means for deciding which of the two modules and in what proportion they assume speed regulation of the motor. | 8 |
This application is a continuation of application number 10/970,458, filed Oct. 21, 2004, status awaiting publication now U.S. Pat. No. 7,275,137.
FIELD OF THE INVENTION
The present invention relates generally to data transmission control, and more particularly, to data transmission control in a memory controller.
DESCRIPTION OF THE RELATED ART
With Extreme Data Rate (XDR™) DRAMs, available from Rambus, Inc., El Camino Real, Los Altos, Calif. 94022, data rate transfers for memory has been dramatically increased. Such features as an octal data rate, which allows for 8 bits of data transmission per cycle, to allow for such increases in speed. Accordingly, the operation of the XDR™ DRAMs require certain propagation and turn-on times to function. As with any DRAM, and its associated control logic, certain periods of time are between activation and data transmission for either reads or writes. Additionally, some DRAMs can require a certain delay requirements. Specifically, XDR™ DRAMs require a minimum of 2 cycles between transition of the Transmission Enable (TX_ENA) and actual data transmission (TDATA). XDR™ DRAMs also require that if the TX_ENA signal toggles to logic low then TX_ENA should remain logic low for a minimum of 4 cycles. Any deviation from these specifications can result in data error and/or data corruption.
Referring to FIG. 1 of the drawings, the reference numeral 100 generally designates a non-operational write for an XDR™ DRAM. Depicted in FIG. 1 are both TX_ENA signals and TDATA signals.
At t 0 , both TDATA and TX_ENA are logic low, signifying no data transmission. Then, at t 1 , TX_ENA transitions to logic high indicating that at some point in the near future that data will be transmitted to the XDR™ DRAM. However, as a result of the design of the XDR™ DRAM, no data can be transmitted before t 3 . TDATA, though, begins transmitting a first write of data at t 3 , so there was not a violation. Data is then continually transmitted until t 7 , where both TDATA and TX_ENA transition to logic low.
In anticipation of a second write of data, TX_ENA transition to logic high again. TDATA is slotted to transmit data at t 10 , at least requiring TX_ENA to transition to logic high at t 8 or earlier. However, since TX_ENA has transitioned to logic low at t 7 and is forced to transition back to logic high at t 8 , a problem exists. XDR™ DRAMs require a turn-off time of TX_ENA for a minimum of 4 clock cycles. However, this XDR™ DRAM specification is violated because TX_ENA remains off for only 1 cycle.
Therefore, there is a need for a method and/or apparatus for better controlling TX_ENA signals in anticipation of data transmission that addresses at least some of the problems associated with conventional memory control.
SUMMARY OF THE INVENTION
In one illustrative embodiment, a method for handling a transmit enable (TxEna) signal in a memory controller comprises generating a queue of bits to track a sequence of commands, providing the transmit enable signal if the queue is empty, and if an entry at a top of the queue indicates a write command, providing the transmit enable signal for a predetermined number of cycles before the transmit enable signal is needed and until write data associated with the entry is transmitted, whereupon on the entry is removed from the queue. If the entry at the top of the queue does not indicate a write command, the method comprises discontinuing the transmit enable signal and removing the entry from the queue.
In another illustrative embodiment, an a apparatus is provided for handling a transmit enable signal in a memory controller. The apparatus comprises transmit enable logic that is configured to provide the transmit enable signal at least for a predetermined number of cycles and for the duration of a write and control logic that provides a feedback signal to the transmit enable logic. The transmit enable logic has at least one feedback loop. The control logic is configured to assert the feedback signal if a next memory command in a sequence of memory commands is a write. The transmit enable logic is configured to keep the transmit enable signal asserted after the number of cycles if the feedback signal asserted.
In another illustrative embodiment, a method for providing a transmit enable signal in a memory controller comprises asserting a transmit enable signal for a predetermined number of cycles, providing a feedback signal based on a sequence of memory commands, and deasserting the transmit enable signal responsive to non-write memory command and the feedback signal being deasserted such that the transmit enable signal remains asserted if the feedback signal is asserted.
These and other features and advantages of the present invention will be described in, or will become apparent to those of ordinary skill in the art in view of, the following detailed description of the example embodiments of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a timing diagram depicting a non-operational write;
FIG. 2 is a timing chart depicting an operational write;
FIG. 3 is a block diagram depicting TX_ENA logic; and
FIG. 4 is a block diagram depicting command logic for the TX_ENA logic;
FIG. 5 is a flow chart depicting the operation of the TX_ENA logic and the TX_ENA command logic.
DETAILED DESCRIPTION
In the following discussion, numerous specific details are set forth to provide a thorough understanding of the present invention. However, those skilled in the art will appreciate that the present invention may be practiced without such specific details. In other instances, well-known elements have been illustrated in schematic or block diagram form in order not to obscure the present invention in unnecessary detail. Additionally, for the most part, details concerning network communications, electro-magnetic signaling techniques, and the like, have been omitted inasmuch as such details are not considered necessary to obtain a complete understanding of the present invention, and are considered to be within the understanding of persons of ordinary skill in the relevant art.
It is further noted that, unless indicated otherwise, all functions described herein may be performed in either hardware or software, or some combinations thereof. In a preferred embodiment, however, the functions are performed by a processor such as a computer or an electronic data processor in accordance with code such as computer program code, software, and/or integrated circuits that are coded to perform such functions, unless indicated otherwise.
Referring to FIG. 2 of the drawings, the reference numeral 200 generally designates a timing diagram depicting operational writes for TX_ENA. Depicted in FIG. 1 are both TX_ENA signals and TDATA signals.
At t 0 , both TDATA and TX_ENA are logic low, signifying no data transmission. Then, at t 1 , TX_ENA transitions to logic high indicating that at some point in the near future that data will be transmitted to the XDR™ DRAM. However, as a result of the design of the XDR™ DRAM, no data can be transmitted before t 3 . TDATA, though, begins transmitting a first write of data at t 3 , so there was not a violation. Data is then continually transmitted until t 7 , where TDATA transition to logic low.
In anticipation of a second write of data, TX_ENA remains at logic high again. TDATA is slotted to transmit data at t 10 , at least requiring TX_ENA to transition to logic high at t 8 or earlier. However, since TX_ENA remains at logic high, data can be safely transmitted. XDR™ DRAMs require a turn-off time of TX_ENA for a minimum of 4 clock cycles, which has been eliminated as a potential barrier.
To accomplish such a task of anticipating additional future writes, however, additional logic is added. Referring to FIG. 3 of the drawings, the reference numeral 300 generally designates a block diagram depicting TX_ENA logic. The TX_ENA logic 300 comprises eight latches 302 , 306 , 308 , 310 , 312 , 316 , 320 , and 328 , an inverter 304 , three AND gates 314 , 324 , and 330 , and two OR gates 322 and 326 .
When initiated, signals are transmitted through communication channels 338 to the latch 306 . A start enable signal is transmitted to the latch 306 . This initial signal allows for the process to begin whereby TX_ENA can transition to logic high in anticipation of data being written to the DRAMs (not shown).
Once the initial data has been transmitted to the latch 306 , the latches 308 , 310 , and 312 are arranged in a cascade configuration to forward the results of the initial signal. The output of the latch 306 is transmitted to the latch 308 and the OR gate 322 through the communication channel 340 . The output of the latch 308 is transmitted to the latch 310 and the OR gate 322 through the communication channel 342 . The output of the latch 310 is transmitted to the latch 312 and the OR gate 322 through the communication channel 344 . By propagating the initial signal from the communication channel 338 , a delay occurs with each propagation. Therefore, the output of the OR gate reflects the result of the initial signal as the signal propagated through the latches
The output of the cascaded latches 306 , 308 , 310 , and 312 is the input to the AND gate 314 . Specifically, the output of the latch 312 is transmitted to the AND gate 314 through the communication channel 346 . In addition to initial signal transmitted to the cascaded latches 306 , 308 , 310 , and 312 , a signal can be transmitted to the latch 302 , as a register configure signal through communication channel 332 . A configuration signal is then output to the inverter 304 through the communication channel 334 . The inverted signal is then transmitted to the AND gate 314 through communication channel 336 . The result of the ANDed inverted signal and the propagated signal is to allow for TX_ENA to enable the proper registers.
After the initial signals have been propagated and ANDed, another set of cascaded latches is employed. The latches 316 and 320 are arranged in a cascaded fashion such that the output of the AND gate 314 is input into the latch 316 . The ANDed signal is transmitted to the latch 316 through the communication channel 348 . The latch 316 then propagates the ANDed signal to the latch 320 and the OR gate 322 through the communication channel 350 . The latch 320 the outputs a signal to the OR gate 322 through communication channel 352 . Hence, the OR gate reflects the proper TX_ENA for the correct register.
Based on the output of OR gate 322 , the TX_ENA transitions to or remains logic high. The OR gate outputs a signal to the AND gate 324 through the communication channel 354 . The AND gate 324 ANDs the resultant OR signal with the inverted Drive Complete Enable (DriveCmpEn) that is communicated to the AND gate 324 through the communication channel 358 . The DriveCmpEn signal can be overwritten by a state bit so that, when a last enable pulse is received, the mode can be switched from TX_ENA to Compare Enable (CMP_ENA). Therefore, the result from the AND gate 324 can be determinative of the state of the system as to whether TX_ENA is logic high or logic low.
The output of AND gate 324 is then transmitted to a feedback loop. The feedback loop comprises the OR gate 326 , the latch 328 , and the AND gate 330 . The OR gate 326 receives the output of the AND gate 324 through the communication channel 360 . The OR gate 326 then feeds the latch 328 through the communication channel 362 . The output of the latch 328 is the TX_ENA signal output through the communication channel 364 . The TX_ENA signal is then ANDed at the AND gate 330 with a feedback signal transmitted through the communication channel 368 . The ANDed output is then fed back to the OR gate 326 through the communication channel 366 . Therefore, the TX_ENA signal can be transitioned to logic low based on the logic states of the feedback signal and the output of the AND gate 324 transmitted through the communication channels 368 and 360 , respectively.
The feedback signal, then, can be a significant factor in the operation of the TX_ENA logic 300 . Referring to FIG. 4 of the drawings, the reference numeral 400 generally designates command logic for the TX_ENA logic. The command logic 400 provides the feedback signal to the communication channel 368 . The command logic comprises four latches 402 , 404 , 406 , and 408 , control logic 410 , a valid queue 412 , and a write queue 414 .
The command logic 400 receives and stores new command and write entries for execution and provides the enabling output to indicate whether the TX_ENA should be logic high or logic low. New command operations are received at the latch 404 through the communication channel 416 . New write data corresponding to each new operation are transmitted to the latch 406 through the communication channel 418 . The new operations and new write data are transmitted from the latch 404 and the latch 406 to the valid queue 412 and the write queue 414 through the communications channels 422 and 424 , respectively.
At the bottom of the queues 412 and 414 is pointing logic, which is the latch 402 . Through the communication channel 420 , the latch 402 indicates the next command to be recorded is stored. Effectively, there is no specific pointer, however, as is common with queues.
The control logic 410 then utilizes the available data to generate the feedback signal to the TX_ENA logic 300 . Data from the valid queue 412 and the write queue 414 indicating the condition of the respective queues is transmitted to the control logic 410 through the communication channel 426 . The control logic 410 also receives a start initialization signal through the communication channel 428 , which is equivalent to the communication channel 344 of FIG. 3 . In attempting to generate control data, the control signal also employs the DriveCmpEn signal, which is the inverted signal transmitted by the communication channel 358 of FIG. 3 . The output of the control logic 410 is then communicated to the latch 408 through the communication channel 430 , which then outputs a feedback signal through the communication channel 432 . The feedback signal is transmitted to the control logic 410 as well as to the logic gate 330 of FIG. 3 because the communication channel 432 is equivalent to the communication channel 368 of FIG. 3 .
Under certain conditions, the control logic 410 provides the control data necessary to generate a logic high TX_ENA signal. To provide such a signal, the start initialization signal is ‘1’ or logic high, and the DriveCmpEn is ‘0’ or logic low. Also, the value from the valid queue 412 is ‘1,’ while the value from the write queue 414 is ‘1.’ Under other conditions, though, where the value from the valid queue 412 is ‘1’ and the value from the write queue 414 is ‘0,’ the feedback loop will be terminated. Essentially, the queues 412 and 414 are received. In other words, when the value from the valid queue 412 is ‘1’ and the value from the write queue 414 is ‘0,’ a read operation is the commanded operation that requires TX_ENA to transition to logic low.
Therefore, the valid queue 412 and the write queue 414 assist in preventing the hardware from violating the predetermined criteria. Effectively, as soon as a read, a write, or a calibration event occurs, the event is logged in the queues 412 and 414 . However, only a write will enable a logic high or ‘1’ output value for the write queue 414 , while the remaining event types will reflect a logic low or ‘0.’ When a write reaches the top of the queues 412 and 414 and is executed, the feedback path is left open. Additionally, the TX_ENA is driven for 6 cycles from the latches 306 , 308 , 310 , 312 , 316 , and 320 of FIG. 3 and until something kills the feedback loop.
The TX_ENA logic 300 and the TX_ENA control logic 400 do, however, operate in conjunction to provide cohesive control of the TX_ENA signal. Referring to FIG. 5 of the drawings, the reference numeral 500 generally designates a flow chart depicting the operation of the TX_ENA logic 300 and the TX_ENA control logic 400 .
Initially, commands are issued to XDRAMs. When a command is received in step 502 , an analysis of the commands begins. A determination is made in step 504 as to whether the command is valid or invalid. If the command is valid, then in step 506 a ‘1’ is written into the valid queue 414 . However, if the command is not valid, then in step 508 a ‘0’ is written into the valid queue 414 . Once the validity has been determined, then in step 509 the command is analyzed to determine whether it is a read or a write command. If the command is a write command, then in step 510 a ‘1’ is written into the write queue 414 . Also, if the command is a read command, then in step 512 a ‘0’ is written into the write queue 414 .
After commands have been accounted for in the queues 412 and 414 , the system waits for execution in step 514 . A determination is then made in step 516 as to whether the queues are empty. If the queues are empty, then in step 514 the system 300 and 400 continues to provide a TX_ENA signal and waits for another execution. Otherwise, a determination is made in step 520 as to whether the command at the top of the queues is a read command or a write command. If the command is a read command, the TX_ENA signal is discontinued in step 522 , but if the command is a write command, then the TX_ENA signal is continued in step 524 . After execution is complete of either a read or write signal, the system 300 and 400 waits for another execution in step 514 .
It is understood that the present invention can take many forms and embodiments. Accordingly, several variations may be made in the foregoing without departing from the spirit or the scope of the invention. The capabilities outlined herein allow for the possibility of a variety of programming models. This disclosure should not be read as preferring any particular programming model, but is instead directed to the underlying mechanisms on which these programming models can be built.
Having thus described the present invention by reference to certain of its preferred embodiments, it is noted that the embodiments disclosed are illustrative rather than limiting in nature and that a wide range of variations, modifications, changes, and substitutions are contemplated in the foregoing disclosure and, in some instances, some features of the present invention may be employed without a corresponding use of the other features. Many such variations and modifications may be considered desirable by those skilled in the art based upon a review of the foregoing description of preferred embodiments. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention. | A mechanism provided for controlling a transmission enable (TX_ENA) signal. The mechanism generates a queue of bits to track a sequence of commands and provides the transmit enable signal if the queue is empty. If an entry at a top of the queue indicates a write command, the mechanism provides the transmit enable signal for a predetermined number of cycles before the transmit enable signal is needed and until write data associated with the entry is transmitted, whereupon the entry is removed from the queue. If the entry at the top of the queue does not indicate a write command, the mechanism discontinues the transmit enable signal and removing the entry from the queue. | 6 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to medical implements and more particularly, to a medical fluid aspirator, which uses an isolation sleeve and an inner filter tube to collect waste solid matters when drawing waste fluid from the incision during a surgery.
[0003] 2. Description of the Related Art
[0004] The body of a human being is composed of skeleton, tendons, blood vessels, muscles and blood. A human being eats food, drinks water, and breaths air to keep the life. However, bacteria and virus or an accident may cause a human being to suffer from a sick or injury. When a human being may have to receive a surgery in order to cure a serious sick or injury. During a surgical incision, waste fluid, muscle and/or bone chips, hairs and other waste matters must be quickly removed from the incision so that the surgery can be performed smoothly. A vacuum pump with a suction implement is usually used to remove waste fluid and waste solid matters from the incision during a surgery. FIGS. 8 and 9 show a conventional medical fluid aspirator for this purpose. According to this design, the medical fluid aspirator comprises a barrel A, which has a small front hole A 1 and a big rear hole A 2 in communication with the small front hole A 1 , a suction tube B connected to the small front hole A 1 , an inner tube C, which is mounted inside the barrel A and which has a plurality of through holes Cl cut through the peripheral wall, a front open end C 2 , and a rear close end C 3 , a holder block C 4 , which is fastened to the rear close end C 3 of the inner tube C and has a plurality of through holes C 41 , and a rear cap D, which is capped on the holder block C 4 . This design of medical fluid aspirator is still not satisfactory in function because of the following drawbacks:
[0005] 1. After installation of the inner tube C in the barrel A, the front open end C 2 is coupled to an inside extension tube of the barrel A. During the operation of the vacuum pump to draw waste fluid and solid waste matters from the incision, waste fluid may flow through a gap between the front open end C 2 of the inner tube C and the inside extension tube of the barrel A. In this case, waste solid matters may be carried with waste fluid through the gap between the front open end C 2 of the inner tube C and the inside extension tube of the barrel A to further block the barrel A.
[0006] 2. The inner tube C is fastened to the inside extension tube of the barrel A. When removing the inner tube C from the barrel A after the surgery, waste fluid and waste solid matters may be scattered all over the floor.
[0007] 3. After installation of the inner tube C in the barrel A, the front open end C 2 of the inner tube C is coupled to the inside extension tube of the barrel A. Because this design of medical fluid aspirator does not use any fastening means to affix the front open end C 2 of the inner tube C to the inside extension tube of the barrel A, the inner tube C may be vibrated and biased during the suction action, thereby affecting the performance of the surgery.
SUMMARY OF THE INVENTION
[0008] The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide to a medical fluid aspirator, which prevents a leakage during the operation. It is another object of the present invention to provide a medical fluid aspirator, which removes waste solid matters from waste fluid passing through, and keeps the collected waste solid matters in place, preventing scattering of the collected waste solid matters after the surgery.
[0009] To achieve these and other objects of the present invention, the medical fluid aspirator comprises a barrel, the barrel having a front suction hole, an inside receiving chamber, a rear connection portion extending around one side of the barrel remote from the front suction hole, an inside connection tube suspending in the inside receiving chamber in communication with the front suction hole; a gasket ring fastened to the periphery of the inside connection tube within the inside receiving chamber; an isolation sleeve inserted into the inside receiving chamber of the barrel, the isolation sleeve having a front inlet sleeved onto the inside connection tube of the barrel and tightly stopped against the gasket ring, a tapered accommodation chamber in communication with the front inlet, and a rear locating flange extending around a rear side of the isolation sleeve remote from the front inlet; an inner filter tube inserted into the tapered accommodation chamber of the isolation sleeve, the inner filter tube having a base stopped outside the rear locating flange of the isolation sleeve, a locating portion forced into engagement with the rear locating flange of the isolation sleeve, a close-end tube extending from the locating portion and suspending in the tapered accommodation chamber of the isolation sleeve, an axial fluid passage cut through the center of the base, and a plurality of filter holes cut through the periphery of the closed-end tube in communication between the axial fluid passage and the tapered accommodation chamber of the isolation sleeve; and an adapter fastened to the rear connection portion of the barrel and stopped against the base of the inner filter tube, the adapter having a drainage hole adapted to guide fluid out of the axial fluid passage of the inner filter tube. After the surgery, the filtered waste solid matters are kept in the tapered accommodation chamber inside the isolation sleeve around the close-end tube of the inner filter tube, and therefore the filtered waste solid matters can be properly disposed off.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a perspective view of a medical fluid aspirator in accordance with the present invention.
[0011] FIG. 2 is an exploded view of the medical fluid aspirator in accordance with the present invention.
[0012] FIG. 3 is a perspective sectional side view of the medial fluid aspirator in accordance with the present invention.
[0013] FIG. 4 is a schematic drawing showing an application example of the present invention.
[0014] FIG. 5 is a sectional side view of the medical fluid aspirator in accordance with the present invention.
[0015] FIG. 6 is a schematic sectional view of the present invention, showing removal of the isolation sleeve with the inner filter tube from the barrel.
[0016] FIG. 7 is a schematic sectional view of the present invention, showing the inner filter tube separated from the isolation sleeve.
[0017] FIG. 8 is a sectional side view of a medical fluid aspirator according to the prior art.
[0018] FIG. 9 is a sectional exploded view of the medical fluid aspirator according to the prior art.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0019] Referring to FIGS. 1˜3 , a medical fluid aspirator in accordance with the present invention is shown comprised of a barrel 1 , an isolation sleeve 2 , an inner filter tube 3 , and an adapter 4 .
[0020] The barrel 1 has an inside receiving chamber 11 , a front suction hole 12 disposed at one side, namely, the front side and attached with a suction tip 121 , an inside connection tube 111 fixedly mounted on the inside in communication between the inside receiving chamber 11 and the front suction hole 12 , a gasket ring 122 fastened to the periphery of the inside connection tube 111 to seal a gap, a rear connection portion 13 disposed at the other side, namely, the rear side, an outer thread 131 extending around the periphery of the rear connection portion 13 .
[0021] The isolation sleeve 2 is a tapered sleeve, having a tapered accommodation chamber 21 , an inlet 22 at the narrow front side of the tapered accommodation chamber 21 , a rear locating flange 23 around the broad rear side of the tapered accommodation chamber 21 , and at least one retaining block 231 on the inside wall of the rear locating flange 23 .
[0022] The inner filter tube 3 has a base 31 at one side, namely, the rear side, a close-end tube 33 at the other side, namely, the front side, a locating portion 32 connected between the base 31 and the close-end tube 33 , a retaining flange 321 formed integral with one end of the locating portion 32 adjacent to the close-end tube 33 and extending around the periphery of the locating portion 32 , an axial fluid passage 331 axially extending through the center of the base 31 and the locating portion 32 into the inside of the close-end tube 33 , and a plurality of filter holes 332 cut through the periphery of the close-end tube 33 in communication with the axial fluid passage 331 .
[0023] The adapter 4 has a front inner thread 411 , a rear connection portion 412 , and a drainage hole 41 axially extending through the two distal ends. The rear connection portion 412 of the adapter 4 is connected to a suction tube 5 .
[0024] During assembly process, the isolation sleeve 2 is inserted into the inside receiving chamber 11 of the barrel 1 to connect the inlet 22 to the inside connection tube 111 and to stop the periphery of the inlet 22 (i.e., the front end of the isolation sleeve 2 ) against the gasket ring 122 , and then the close-end tube 33 of the inner filter tube 3 is inserted into the tapered accommodation chamber 21 of the isolation sleeve 2 to force the locating portion 32 and the retaining flange 321 into engagement with the rear locating flange 23 and the retaining block 231 respectively, and then the front inner thread 411 of the adapter 4 is threaded onto the outer thread 131 of the barrel 1 , and then the rear connection portion 412 of the adapter 4 is connected to the suction tube 5 . Thus, the medical fluid aspirator is assembled for application.
[0025] In an alternate form of the present invention, the isolation sleeve 2 and the inner filter tube 3 are made in integrity, keeping the closed-end tube 33 suspending in the tapered accommodation chamber 21 of the isolation sleeve 2 .
[0026] Referring to FIGS. 4 and 5 , when in use, the suction tip 121 of the barrel 1 is approached to an incision so that the suction pump (not shown) that is connected to the suction tube 5 draw waste fluid and waste solid matters from the incision into the tapered accommodation chamber 21 of the isolation sleeve 2 through the front suction hole 12 and the inside connection tube 111 of the barrel 1 and then from the tapered accommodation chamber 21 into the suction tube 5 through the filter holes 332 and axial fluid passage 331 of the inner filter tube 3 and the drainage hole 41 of the adapter 4 . At this time, the filter holes 332 remove solid matters of diameters greater than the filter holes 332 from the waste fluid, preventing blocking of the suction tube 5 and the suction pump by waste solid matters.
[0027] As stated above, the front end of the isolation sleeve 2 is stopped against the gasket ring 122 so that waste fluid does not leak out of the isolation sleeve 2 .
[0028] Referring to FIGS. 6 and 7 , after the use of the medical fluid aspirator, the isolation sleeve 2 and the inner filter tube 3 must be removed from the barrel 1 for cleaning and sterilization. At this time, disconnect the front inner thread 411 of the adapter 4 from the outer thread 131 of the barrel 1 , and then remove the isolation sleeve 2 and the inner filter tube 3 from the inside receiving chamber 11 of the barrel 1 . After removal of the isolation sleeve 2 and the inner filter tube 3 from the barrel 1 , the residual waste solid matters are kept in the tapered accommodation chamber 21 of the isolation sleeve 2 around the close-end tube 33 of the inner filter tube 3 and can be well collected and properly disposed off. After disconnection of the locating portion 32 of the inner filter tube 3 from the rear locating flange 23 of the isolation sleeve 2 , the barrel 1 , the isolation sleeve 2 , the inner filter tube 3 and the adapter 4 are well washed and sterilized for a repeated use.
[0029] As stated above, the inside receiving chamber 11 of the barrel 1 receives the isolation sleeve 2 and the inner filter tube 3 , and the isolation sleeve 2 is fastened to the inside connection tube 111 of the barrel 1 and firmly stopped against the gasket ring 122 , preventing a leakage.
[0030] In actual practice, the medical fluid aspirator of the present invention has the follow benefits:
[0031] 1. The inlet 22 of the isolation sleeve 2 is connected to the inside connection tube 111 of the barrel 1 , and the gasket ring 122 seals the gap between the isolation sleeve 2 and the inside connection tube 111 , preventing a leakage.
[0032] 2. By means of the suction tip 121 , waste fluid and waste solid matters can be efficiently drawn through the medical fluid aspirator into the suction tube 5 . Further, the filter holes 332 of the close-end tube 33 of the inner filter tube 3 remove waste solid matters from waste fluid, preventing block of the suction tube 5 and the suction pump by waste solid matters. After removal of the isolation sleeve 2 with the inner filter tube 3 from the barrel 1 , waste solid matters are kept in the tapered accommodation chamber 21 of the isolation sleeve 2 around the close-end tube 33 of the inner filter tube 3 and can be properly disposed off.
[0033] 3. The inlet 22 of the isolation sleeve 2 is fastened to the inside connection tube 111 of the barrel 1 and firmly stopped against the gasket ring 122 . Therefore, the isolation sleeve 2 does not vibrate relative to the barrel 1 during the operation of the medical fluid aspirator.
[0034] Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. | A medical fluid aspirator, which includes a barrel attached with a suction tip, a tapered isolation sleeve detachably fastened to an inside connection tube inside the barrel and sealed with a gasket ring, an inner filter tube suspending in the isolation sleeve and tightly fastened to the rear side of the isolation sleeve for removing waste solid matters from waste fluid passing from the suction tip through the inner filter tube during the surgery, and an adapter that connect a suction tube to the rear side of the inner filter tube. | 0 |
FIELD OF THE INVENTION
[0001] This invention relates to automatic pool cleaners (APCs) configured to move autonomously within liquid-containing bodies such as swimming pools and spas and more particularly, although not necessarily exclusively, to components of APCs that frictionally contact surfaces of the pools and spas.
BACKGROUND OF THE INVENTION
[0002] Commonly-owned U.S. Patent Application Publication No. 2011/0314617 of van der Meijden, et al., discloses various components of APCs. Among components illustrated in the van der Meijden application are devices referenced as “scrubbers.” As detailed in the van der Meijden application, an exemplary scrubber may include blades, a shaft, and optionally a gear.
In use, [the] scrubber desirably rotates about [the] shaft so as to move water . . . toward [an] inlet of [a] body of [an] automatic pool cleaner. Such rotation may be caused by interaction of [the] gear with a corresponding gear or other device typically located within [the] body.
See van der Meijden, pp. 1-2, ¶ 0026 (numerals omitted). The rotation and evacuation of water entering the inlet additionally produces “down force” tending to enhance traction of the APC as it moves along a surface within a pool.
[0004] Also described in the van der Meijden application as another optional part of a scrubber is a “wear surface.” If present, the wear surface may be located centrally among the blades of the scrubber and coaxial with the shaft. At least at times in use, the wear surface may contact a surface to be cleaned. See id., p. 2, ¶ 0028.
[0005] Even though the van der Meijden application contemplates frictional contact between the wear surface and surfaces of a pool or spa, additional scrubbing action may be desirable—at least at times—for cleaning purposes. Including brushes spaced from (i.e. not coaxial with) the shaft of a scrubber also may be advantageous, as may be utilizing bristles which contact a surface as the scrubber rotates about the shaft. Removably attaching the brushes to a scrubber further may be beneficial, as in such cases the brushes may be removed from the scrubber when not needed.
SUMMARY OF THE INVENTION
[0006] The present invention provides these types of brushes useful especially (although not necessarily exclusively) with the scrubbers and APCs of the types identified in the van der Meijden application. Brushes of the invention may clip to a hub of a scrubber so as to attach to, and detach from, the scrubber easily. The brushes also preferably flex when a scrubber rotates.
[0007] At least some versions of the brushes may include fingers having bristles protruding outward on either or both of opposed sides of the fingers. Prior to rotation of the scrubbers, the fingers nominally are generally perpendicular to the surface on which the associated APC rests. As scrubbers rotate, however, the fingers flex (e.g. lay over) and become more parallel to the surface. Flexing of the fingers in this manner in turn causes bristles on one side of fingers to become more perpendicular to the surface, thus readily frictionally contacting it.
[0008] Because in use scrubbers of the present invention rotate about an axis generally perpendicular to the pool surface, their brush speeds relative to the surface are faster than those of passive devices (which typically are dragged along the surface) or rollers (which typically rotate about an axis parallel to the surface and in the same direction as the wheels of the cleaner). Such rotation also requires less surface-area contact between the brushes and pool surface to scrub an equivalent width of pool surface than would a roller, whose length must span that entire width. This decreased surface-area contact of the brushes produces less resistance on the drive system of the APC than would rollers, potentially enhancing the longevity and robustness of the drive system.
[0009] Brushes may be attached as desired to a scrubber. Presently preferred is that at least two brushes be used with a scrubber and positioned symmetrically about the shaft. Fewer or more than two brushes may be used in connection with any particular scrubber, however, and conceivably more than one brush may be attached in a particular location.
[0010] It thus is an optional, non-exclusive object of the present invention to provide components for APCs.
[0011] It also is an optional, non-exclusive object of the present invention to provide improvements to scrubbers of the type identified in the van der Meijden application.
[0012] It is another optional, non-exclusive object of the present invention to provide brushes configured to contact to-be-cleaned surfaces.
[0013] It is an additional optional, non-exclusive object of the present invention to provide brushes that may clip, or otherwise attach, to scrubbers so as to rotate as the blades rotate.
[0014] It is, moreover, an optional, non-exclusive object of the present invention to provide brushes that include flexible fingers with bristles protruding therefrom.
[0015] It is a further optional, non-exclusive object of the present invention to provide brushes whose fingers flex as their associated blades rotate, thus causing contact between their bristles and a to-be-cleaned surface of a pool or spa.
[0016] It is yet another optional, non-exclusive object of the present invention to provide brushes which rotate about an axis perpendicular to the to-be-cleaned surface so as to produce faster speeds and less load on drive systems than do certain passive devices and rollers.
[0017] Other objects, features, and advantages of the present invention will be apparent to those skilled in relevant fields with reference to the remaining text and the drawings of this application.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1A is an elevational view of an exemplary scrubber similar to that of those of the van der Meijden application.
[0019] FIG. 1B is a perspective view of the scrubber of FIG. 1A .
[0020] FIGS. 2A-C are various views of an exemplary brush configured to attach to the scrubber of FIG. 1A .
[0021] FIG. 3 is an elevational view of the scrubber of FIG. 1A to which two brushes of FIGS. 2A-C have been attached.
[0022] FIG. 4 is a perspective view of the scrubber of FIG. 1A to which one brush of FIGS. 2A-C has been attached for purposes of showing its flexibility.
[0023] FIG. 5 is a perspective view of an APC including two scrubbers, to each of which brushes have been attached in a manner similar to FIG. 3 .
DETAILED DESCRIPTION
[0024] Depicted in FIGS. 1A-B is exemplary scrubber 10 . Scrubber 10 , which is generally similar to scrubbers of the van der Meijden application, may include blades 14 and shaft 18 . Also illustrated in FIGS. 1A-B is hub 20 interconnecting blades 14 and shaft 18 . In use, scrubber 10 desirably rotates about shaft 18 so as to move water toward an inlet 21 of a cleaner such as APC 22 (see FIG. 5 ). When the APC 22 is upright on a bottom surface of a pool, shaft 18 will be generally perpendicular to the plane of the bottom surface and thus scrubber 10 will rotate about an axis perpendicular (or generally so) to the bottom surface.
[0025] Consistent with the discussion in the van der Meijden application, blades 14 preferably are “semi-rigid” in nature, meaning that they have sufficient flexibility to accommodate passage into inlet 21 of APC 22 , without blockage, of at least some larger types of debris often found in outdoor swimming pools. The term “semi-rigid” also means that blades 14 nevertheless have sufficient rigidity to move volumes of water toward the inlet 21 of the cleaner as they rotate about shaft 18 . A presently-preferred material from which blades 14 is made remains molded thermoplastic polyurethane, although other materials may be used instead.
[0026] Scrubber 10 advantageously may include six blades 14 extending radially from shaft 18 . Fewer or greater numbers of blades 14 may be employed as appropriate, however. As illustrated in FIG. 5 , two scrubbers 10 preferably are employed as part of APC 22 , with each scrubber 10 being positioned at least partly to a side of inlet 21 of the APC 22 . Again, though, fewer or greater numbers of scrubbers 10 may be utilized, and each or any scrubber 10 may be positioned in any suitable location.
[0027] As shown in FIG. 1A , many of the six blades 14 are circumferentially spaced approximately forty-five degrees, rather than approximately sixty degrees, from adjacent blades 14 . This is because attachment assemblies 26 of hub 20 have, in effect, replaced the seventh and eighth blades. The two attachment assemblies 26 are at least partially visible in FIG. 1A spaced circumferentially about shaft 18 by approximately one hundred eighty degrees. Symmetrical positioning of attachment assemblies 26 about shaft 18 presently is preferred, although situations may arise in which an odd number of assemblies 26 , or asymmetrical positioning of an even number of assemblies 26 , is desired.
[0028] The exemplary attachment assembly 26 of FIG. 1A may comprise at least one recess 30 A. In the version of scrubber 10 depicted in FIG. 1A , recess 30 A is formed by a pair of spaced walls 34 A-B connected to hub 20 . A second recess 30 B, formed by a pair of spaced walls 38 A-B connected to hub 20 , also appears in FIG. 1A .
[0029] Shown especially in FIGS. 2A-C is exemplary brush 42 . Included as part of brush 42 is member 46 , which is sized and shaped to be frictionally fitted into recesses 30 A and 30 B. Concurrently, clips 50 of brush 42 frictionally slide along walls 34 A-B and 38 A-B. Manipulating brush 42 in this manner connects the brush 42 to scrubber 10 for use—as shown in FIGS. 3-5 . Because brush 42 is likely to wear through use, it preferably may be detached from scrubber 42 (as through manual force, for example) for replacement.
[0030] Also included as parts of brush 42 are brush body 54 , fingers 58 , and bristles 62 . Fingers 58 depend from body 54 , with each finger 58 comprising opposed major sides 66 A-B. Bristles 52 protrude outward from these major sides 66 A-B. Although FIGS. 2A-5 illustrate three fingers 58 depending from each body 54 , more or fewer fingers 58 may be present instead if appropriate or desired.
[0031] Fingers 58 beneficially are flexible. Accordingly, as shown in FIG. 4 , fingers 58 may flex as blades 14 rotate about shaft 18 . Whereas major sides 66 A-B are nominally vertical when APC is upright (e.g. FIG. 5 ) and blades 14 are not rotating, flexing of fingers 58 causes major sides 66 A-B to become more closely parallel to the surface to be cleaned. Consequently, because bristles 52 protrude outward from major sides 66 A-B, these bristles 52 become more closely perpendicular to the to-be-cleaned surface as the fingers 58 flex. Bristles 52 thus in use may contact the to-be-cleaned surface so as to “scrub” the surface and suspend bottom-dwelling debris into the water of the pool for evacuation into inlet 21 of APC 22 . Consistent with other suction-type APCs, APC 22 also may include body 70 through which the evacuated water may flow to outlet 74 and then into a hose, all under influence of a pump.
[0032] Moreover, because scrubber 10 rotates about an axis perpendicular to the to-be-cleaned surface, the speed of movement of brushes 42 (and hence of bristles 52 ) relative to the surface may be faster than that of passive devices which merely are dragged along the surface. This relative speed of movement likewise may be faster than that of rollers, which typically rotate about axes parallel to the surface and in the same direction as the wheels or tracks of an associated cleaner. Rotation of scrubber 10 about the perpendicular axis also requires approximately fifty percent less surface-area contact between brushes 42 and the pool surface to scrub an equivalent width of pool surface than would a roller, whose length must span that entire width. This decreased surface-area contact of brushes 42 produces less resistance on the drive system of APC 22 than would rollers, potentially enhancing the longevity and robustness of the drive system.
[0033] If scrubber 10 is configured to rotate only in one direction, bristles 52 need necessarily be present only on whichever of major sides 66 A or 66 B is the “leading” side for purpose of the rotation (as the other, “trailing” major side will flex away from the to-be-cleaned surface). It nevertheless may be advantageous to include bristles 52 on the trailing major side 66 B or 66 A of brush 42 so that, when bristles 52 on the leading side wear, brush 42 may be switched to a circumferentially opposite location on scrubber 10 so that the previously-trailing side becomes the leading side and presents unworn bristles 52 to the to-be-cleaned surface. This switch effectively can double the useful life of a brush 42 . (And of course, if scrubber 10 ever is configured to rotate both clockwise and counterclockwise, including bristles 52 on both major sides 66 A-B may be valuable.)
[0034] The foregoing is provided for purposes of illustrating, explaining, and describing embodiments of the present invention. Modifications and adaptations to these embodiments will be apparent to those skilled in the art and may be made without departing from the scope or spirit of the invention. Also, although “pool” and “spa” are sometimes used separately, any reference to “pool” herein may include a spa, hot tub, or other vessel in which water is placed for swimming, bathing, therapy, or recreation. Finally, incorporated herein in their entirety by this reference are the contents of the van der Meijden application. | Components of automatic pool cleaners (APCs) are detailed. The components may include brushes configured to attach to blades of scrubbers of the APCs. The flexible brushes may rotate as their associated blades rotate and have fingers which flex so as to adduce contact between a to-be-cleaned pool or spa surface and bristles protruding outward from sides of the fingers. | 4 |
CROSS REFERENCE TO RELATED APPLICATION
This application claims priority to and the benefit of Korean Patent Application No. 10-2004-0012633 filed on Feb. 25, 2004 in the Korean Intellectual Property Office, the entire content of which is incorporated herein by reference.
FIELD OF THE INVENTION
The present invention relates to an electron emission device, and more particularly, to an electron emission device equipped with a metal grid electrode that focuses electrons emitted from an electron emitting region.
BACKGROUND OF THE INVENTION
An electron emission device (EED) generally comprises a display apparatus from which an arbitrary image is realized when electrons emitted from an electron emitting region of a cathode electrode irradiate. The electrons irradiate through the tunneling effect of quantum mechanics, by colliding with a phosphor layer formed on an anode. A triode consisting of a cathode electrode, a gate electrode, and an anode electrode is a widely used structure for an EED.
A commonly used triode consists of a vacuum container comprising a rear substrate comprising a cathode electrode and a gate electrode and a front substrate comprising an anode electrode. The vacuum container is put together using a sealant, such as a frit. The vacuum container includes several spacers creating a fixed gap between the rear and front substrates to keep the rear substrate away from the front substrate.
An arc discharge is generated in the vacuum container by the electron emission device. It can be inferred that the arc discharge is generated by the simultaneous ionization of a great deal of gas by outgassing, which occurs in the vacuum container. Generally, the arc discharge generated becomes more severe as the anode voltage increases. Due to this arc discharge, the gate electrode can be easily damaged because the anode electrode can be electrically shorted with the gate electrode.
To resolve this problem, an electron emission device has been proposed in which a metal grid electrode is equipped between the rear substrate and the front substrate. The grid electrode can protect the electrodes equipped on the rear substrate from damage due to generation of the arc discharge, and improves the capability of focusing the emitted electrons.
However, when the thermal expansion coefficient of the metal grid electrode differs remarkably from the thermal expansion coefficient of heat-reinforced glass used for the front and rear substrate of a flat panel display, several problems occur during the sealing and exhaust processes of the electron emission device. One such problem is the limited availability of high temperature processes. Another problem is that the panel can be damaged during the exhaust process when the grid electrode and underplate are misaligned. Moreover, electrons emitted from the electron emitting region may collide with the phosphor layer of a surrounding territory instead of the selected territory due to the misalignment of the grid electrode, and the color purity can depreciate.
To solve these problems, a design has been introduced which compensates for the misalignment of the grid electrode generated during the heat treatment process. However, this design uses a troublesome process and has certain limitations in quality control.
SUMMARY OF THE INVENTION
In one embodiment of the present invention, an electron emission device is provided that is capable of preventing misalignment due to a difference of thermal expansion coefficients between the grid electrode and front and rear substrates by providing a metallic grid electrode having a thermal expansion coefficient similar to those of the first and second substrates.
In a first embodiment, the electron emission device (EED) comprises a first substrate and a second substrate constituting a vacuum container, positioned opposite each other with a predetermined gap therebetween; cathode electrodes and gate electrodes provided in an insulating state on an insulating layer on the first substrate; electron emitting regions comprising an electron emitting material, formed on the cathode electrode; at least one anode electrode and phosphor layers of a red, a green, and a blue color provided on the second substrate; and a grid electrode installed in the vacuum container, and equipped with holes for passing of electrons emitted from the electron emitting region, wherein a thermal expansion coefficient of the grid electrode is in the range of 80 to 120% of the thermal expansion coefficient of the first and second substrates.
In a second embodiment, the electron emission device (EED) comprises a first substrate and a second substrate constituting a vacuum container, positioned opposite each other with a predetermined gap therebetween; cathode electrodes and gate electrodes provided in an insulating state on an insulating layer on the first substrate; electron emitting regions comprising an electron emitting material, formed on the cathode electrode; at least one anode electrode and phosphor layers of a red, a green, and a blue color provided on the second substrate; and a grid electrode installed in the vacuum container, and equipped with holes for passing of electrons emitted from the electron emitting region, wherein the grid electrode comprises a nickel-iron alloy.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other advantages of the present invention will be better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:
FIG. 1 is a partially exploded perspective view of an electron emission device according to one embodiment of the present invention;
FIG. 2 is a partial cross-sectional view of the electron emission device of FIG. 1 ;
FIG. 3 is a partially exploded perspective view of an electron emission device comprising a grid electrode according to another embodiment of the present invention;
FIG. 4 is a partial cross-sectional view of the electron emission device shown in FIG. 3 ;
FIG. 5 is a graph showing the relationship of the thermal expansion coefficient of a metal grid electrode to the nickel content of the grid electrode;
FIG. 6 is a pictorial representation of the alignment of electrodes on the first substrate of an electron emission device fabricated according to Example 3; and
FIG. 7 is a pictorial representation of the alignment of electrodes on the first substrate of an electron emission device fabricated according to Comparative Example 1.
DETAILED DESCRIPTION
In the first embodiment, the electron emission device (EED) comprises a first substrate and a second substrate constituting a vacuum container, positioned opposite each other with a predetermined gap therebetween; cathode electrodes and gate electrodes provided in an insulating state on an insulating layer on the first substrate; electron emitting regions comprising an electron emitting material, formed on the cathode electrode; at least one anode electrode and phosphor layers of a red, a green, and a blue color provided on the second substrate; and a grid electrode installed in the vacuum container, and equipped with holes for passing of electrons emitted from the electron emitting region, wherein a thermal expansion coefficient of the grid electrode is in the range of 80 to 120% of the thermal expansion coefficient of the first substrate and the second substrate.
In the second embodiment, the electron emission device (EED) comprises a first substrate and a second substrate constituting a vacuum container, positioned opposite each other with a predetermined gap therebetween; cathode electrodes and gate electrodes provided in an insulating state on the other side of an insulating layer on the first substrate; electron emitting regions comprising an electron emitting material, formed on the cathode electrode; at least one anode electrode and phosphor layers of a red, a green, and a blue color provided on the second substrate; and a grid electrode installed in the vacuum container, and equipped with holes for passing of electrons emitted from the electron emitting region, wherein the grid electrode comprises a nickel-iron alloy.
The present invention is described in more detail with reference to the accompanying drawings. However, the present invention is not limited by the structure of the drawings. Rather, the drawings illustrate examples of the electron emission device of the present invention.
As used herein, the “first substrate” refers to a front substrate comprising the phosphor layers, and the “second substrate” refers to a rear substrate comprising the electron emitting regions.
FIG. 1 is a partially exploded perspective view of an electron emission device comprising a grid electrode according to one embodiment of the present invention. FIG. 2 is a partial cross-sectional view of the electron emission device shown in FIG. 1 .
With reference to FIGS. 1 and 2 , the electron emission device comprises a first substrate 2 and a second substrate 4 which constitute a vacuum container. The first substrate 2 and the second substrate 4 are positioned facing each other and separated from each other by a predetermined distance. A grid electrode 8 is positioned between the first substrate 2 and the second substrate 4 . The grid electrode 8 comprises several openings 6 to allow passage of an electron beam. An electron forming region for emitting electrons is provided on the first substrate 2 . An image realizing region is provided on the second substrate. A visual light is irradiated from the image realizing region by electrons emitted from the first substrate 2 to the second substrate 4 .
More particularly, the gate electrodes 10 are positioned on the first substrate 2 in a striped pattern, and each gate electrode 10 extends along the Y direction. An insulating layer 12 is positioned over the gate electrodes 12 on the side of the first substrate 2 facing the second substrate 4 . The cathode electrodes 14 are positioned on the insulating layer 12 in a striped pattern, and each cathode electrode 14 extends along the X direction, perpendicular to the gate electrodes 10 . An electron emitting region 16 for an electron emission source is positioned on the edge of the cathode electrode 14 at each point where the cathode electrodes 14 intersect the gate electrodes 10 .
If desired, a counter electrode 18 can be positioned on the first substrate 2 . The counter electrode 18 is electrically connected to the gate electrode 10 by contact through a hole 12 a formed in the insulating layer 12 . The counter electrode 18 is positioned between the cathode electrodes 14 and separated from the electron emitting region 16 by a predetermined distance. The counter electrode 18 provides a stronger electric field in the area surrounding the electron emitting region 16 , such that electrons are favorably emitted from the electron emitting region 16 .
Additionally, an anode electrode 20 is formed on the side of the second substrate 4 facing the first substrate 2 . Red, green and blue phosphor layers 22 are provided on the anode electrode 20 . Phosphor screens 26 consisting of black color layers 24 , are formed on the anode electrode 20 and positioned between the phosphor layers 22 . The anode electrode 20 comprises a transparent electrode such as indium tin oxide (ITO). As shown in FIGS. 1 and 2 , the anode electrode 20 comprises one electrode formed on the entire surface of the second substrate 4 . Alternatively, the anode electrode 20 may comprise several electrodes formed on the substrate in a pattern corresponding with the pattern of the phosphor layers 22 . If desired, a metal layer (not shown) can be positioned on the surface of the phosphor screens 26 to improve brightness by a metal back effect. In this embodiment, the transparent electrode can be omitted and the metal layer used as the anode electrode.
Moreover, a grid electrode 8 for focusing the electron beam is positioned between the first substrate 2 and the second substrate 4 , but is positioned closer to the first substrate 2 . The grid electrode 8 comprises a metal plate having several openings 6 to allow passage of the electron beam. The grid electrode 8 is positioned in the vacuum container by upper spacers 28 situated between the second substrate 4 and the grid electrode 8 and lower spacers 30 situated between the first substrate 2 and the grid electrode 8 . The spacers 28 and 30 separate the grid electrode 8 from first and second substrates by a predetermined, constant distance.
FIG. 3 is a partially exploded perspective view of an electron emission device comprising a grid electrode according to another embodiment of the present invention. FIG. 4 is a partial cross-sectional view of the electron emission device shown in FIG. 3 .
With reference to FIGS. 3 and 4 , the electron emission device (EED) includes a first substrate 2 , of predetermined dimensions, and a second substrate 4 , of predetermined dimensions. The first substrate 2 is provided substantially in parallel with the second substrate 4 with a predetermined gap therebetween. The first substrate 2 and the second substrate 4 are connected in this configuration to define an exterior of the EED and to form a vacuum assembly.
An emission structure to enable the emission of electrons by an electric field is formed on the second substrate 4 , and an illumination structure to enable the realization of predetermined images by interaction with electrons is formed on the first substrate 2 .
In more detail, for the emission structure, cathode electrodes 14 are formed in a stripe pattern, and an insulating layer 12 is formed over an entire surface of the second substrate 4 covering the cathode electrodes 14 . Further, gate electrodes 10 are formed in a stripe pattern on the insulating layer 12 . Holes 10 a and 12 a are formed in the gate electrodes 10 and the insulating layer 12 , and electron emitting regions 16 are formed on the cathode electrodes 14 in the same areas exposed through the holes 10 a and 12 a.
With respect to the illumination structure for realizing predetermined images, anode electrodes 20 are formed on a surface of the first substrate 2 opposing the second substrate 4 . Also, phosphor layers 22 and black color layers 24 are formed on the anode electrodes 20 . The phosphor layers 22 are illuminated by electrons emitted from the electron sources 16 of the second substrate 4 .
With this structure, if electrons are emitted from the electron emitting regions 16 by the voltage difference between the cathode electrodes 14 and the gate electrodes 10 , the electrons are attracted by a high voltage applied to the anode electrodes 20 to strike the phosphor layers 22 and excite the same.
A grid electrode 8 is mounted between the first substrate 2 and the second substrate 4 to prevent arc discharge between these elements and to aid in focusing the emitted electrons. Preferably, the grid electrode 8 includes a plurality of openings 6 , each opening 6 corresponding to one electron emitting region 16 . The grid electrode 8 is positioned in the vacuum container by upper spacers 28 situated between the second substrate 4 and the grid electrode 8 and lower spacers 30 situated between the first substrate 2 and the grid electrode 8 . The spacers 28 and 30 separate the grid electrode 8 from the first and second substrates by a predetermined, constant distance.
In the said EEDs, the electron emitting regions 16 comprise a carbon-based material. Preferably, the carbon-based material is selected from the group consisting of carbon nanotubes, graphite, diamond, diamond-like carbon, fullerene (C60), and mixtures thereof.
Preferably, the first and second substrates comprise glass substrates having thermal expansion coefficients ranging from about 1.0×10 −6 to about 10.0×10 −6 /° C. More preferably, the first and second substrates comprise heat-reinforced glass substrates having thermal expansion coefficients ranging from about 1.0×10 −6 to about 10.0×10 −6 /° C.
The thermal expansion coefficient of the grid electrode ranges from about 80 to about 120% of the thermal expansion coefficient of the first and second substrates 2 and 4 , preferably about 90 to about 110%, and more preferably about 95 to about 105%. When the thermal expansion coefficient of the grid electrode is less than about 80% or more than about 120% of the thermal expansion coefficient of the glass substrate, the possibility of a misalignment increases. Therefore, the difference in thermal expansion coefficients between the grid electrode and the glass substrates is preferably as small as possible.
The thermal expansion coefficient of the grid electrode is controllable by controlling the nickel content of a nickel-iron alloy. For example, when the first and second substrates 2 and 4 , respectively, comprise heat-reinforced glass having a thermal expansion coefficient ranging from about 1.0×10 −6 to about 10.0×10 −6 /° C., a grid electrode comprising a nickel-iron alloy with a nickel content ranging from about 42 to about 52 wt % can be used. Preferably, the nickel content ranges from about 45 to about 50 wt. %, more preferably about 47 to about 49 wt. %.
A 36 nickel-iron alloy, i.e. an alloy with a nickel content of 36 wt. %, has previously been used as the grid electrode or the shadow mask for a cathode-ray tube (CRT). However, such an alloy is inadequate for high temperature processes and misalignment easily occurs between the grid electrode and the lower plate because the thermal expansion coefficient of this 36 nickel-iron alloy is substantially smaller than the thermal expansion coefficient of the first and second substrates in the flat panel display. However, the nickel-iron alloy having a nickel content in the range of 42 to 52 wt %, as used in the present invention, has a thermal expansion coefficient in the desired range, substantially eliminating the misalignment problems and the problems associated with high temperature processes.
The grid electrode of the present invention mainly comprises the nickel-iron alloy. In addition, however, a metal selected from the group consisting of chromium, cobalt, or titanium, may optionally be included to impart desired physical and mechanical properties, for example etching and workability. Chromium, cobalt, or titanium are present in the nickel-iron alloy in an amount according to necessity. Preferably, however, chromium is present in an amount ranging from about 0.01 to about 10 wt. %.
In one embodiment, the thickness of the grid electrode ranges from about 0.05 to about 0.2 mm. When the thickness of the grid electrode is less than about 0.05 mm, mechanical handling of the electrode is difficult. When the thickness of the grid electrode is greater than about 0.2 mm, processing of a microscopic hole is difficult.
The electron emission device comprising a grid electrode of the present invention can be fabricated according to a top-gate form, an under-gate form, or a modified form with reference to the position of the gate electrode, and is not limited by an electron emission device of a specific structure.
Hereafter, examples of the present invention are described. The examples described below are only examples of the present invention, and the present invention is not limited by these examples.
EXAMPLE 1
Heat-reinforced glass (PD-200) having a thermal expansion coefficient (TEC) of 8.6×10 −6 /° C. was used as the first and second substrates. The grid electrode was manufactured using a nickel-iron alloy comprising 42 wt % nickel. An electron emission device was fabricated according to the structure shown in FIG. 1 .
EXAMPLE 2
An electron emission device was fabricated according to the method described in Example 1, except that the grid electrode was manufactured using a nickel-iron alloy comprising 45 wt % nickel.
EXAMPLE 3
An electron emission device was fabricated according to the method described in Example 1, except that the grid electrode was manufactured by using a nickel-iron alloy comprising 47 wt % nickel.
EXAMPLE 4
An electron emission device was fabricated according to the method described in Example 1, except that the grid electrode was manufactured using a nickel-chromium-iron alloy comprising 42 wt % nickel, 6 wt % chromium and 52 wt % iron.
COMPARATIVE EXAMPLE 1
An electron emission device was fabricated according to the method described in Example 1, except that the grid electrode was manufactured using a nickel-iron alloy comprising 36 wt % nickel.
FIG. 5 is a graph showing the relationship of the thermal expansion coefficient of a metal grid electrode to the nickel content of the grid electrode. The area enclosed in dotted lines shows a thermal expansion coefficient of heat-reinforced glass of about 8.6×10 −6 /° C.
The following table lists the thermal expansion coefficients (TEC) of the grid electrodes used in Examples 1 to 4 and Comparative Example 1.
TABLE 1
Comparative
Example 1
Example 2
Example 3
Example 4
Example1
TEC
6.9 × 10 −6
7.7 × 10 −6
8.2 × 10 −6
7.5 × 10 −6
4.0 × 10 −6
(/° C.)
Misalignment does not occur during the sealing and exhausting processes in the electron emission devices of Examples 1 to 4, but does occur during the sealing and exhausting processes in the electron emission device of Comparative Example 1, which generates a damaged part.
FIGS. 6 and 7 are microscopic pictures showing the alignment of electrodes on the first substrate of the electron emission devices of Example 3 and Comparative Example 1, respectively. As shown in FIG. 6 , the cathode electrodes of the electron emission device of Example 3 can be seen through the openings in the grid electrodes, indicating exact alignment of the electrodes. On the contrary, as shown in FIG. 7 , the cathode electrodes of the electron emission device of Comparative Example 1 are offset, indicating misalignment of the electrodes.
The misalignment occurs due to a difference of the thermal expansion coefficient between the grid electrode and the front or rear substrate. This misalignment can be prevented, as it is in the present invention, by adopting a metallic grid electrode having a thermal expansion coefficient similar to that of the first and second substrates. In so doing, alignment precision is improved, high temperature processes are possible, and the reliability of the device is improved. | The present invention relates to an electron emission device, and more particularly, to an electron emission device comprising a grid electrode having a thermal expansion coefficient ranging from about 80 to about 120% of the thermal expansion coefficient of the first or second substrate of the electron emission device. The grid electrode is fixed in position by minimizing misalignment caused by a difference in thermal expansion coefficients between the grid electrode and the first and second substrates of the electron emission device. The grid electrode also minimizes generation of arc discharge. However, even when arc discharge is generated, the grid electrode prevents damage to the cathode electrodes and gate electrodes from that arc discharge. According to the present invention, an electron emission device with increased brightness and resolution is easily realized by applying increased voltage to the anode electrode. | 7 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of priority to the following United States provisional patent applications which are incorporated herein by reference in their entirety:
Ser. No. 60/989,957 entitled “Point-to-Point Communication within a Mesh Network”, filed Nov. 25, 2007 (Attorney Docket No. TR0004-PRO); Ser. No. 60/989,967 entitled “Efficient And Compact Transport Layer And Model For An Advanced Metering Infrastructure (AMI) Network,” filed Nov. 25, 2007 (Attorney Docket No. TR0003-PRO); Ser. No. 60/989,958 entitled “Creating And Managing A Mesh Network Including Network Association,” filed Nov. 25, 2007 (Attorney Docket No. TR0005-PRO); Ser. No. 60/989,964 entitled “Route Optimization Within A Mesh Network,” filed Nov. 25, 2007 (Attorney Docket No. TR0007-PRO); Ser. No. 60/989,950 entitled “Application Layer Device Agnostic Collector Utilizing ANSI C12.22,” filed Nov. 25, 2007 (TR0009-PRO); Ser. No. 60/989,953 entitled “System And Method For Real Time Event Report Generation Between Nodes And Head End Server In A Meter Reading Network Including From Smart And Dumb Meters,” filed Nov. 25, 2007 (Attorney Docket No. TR0010-PRO); Ser. No. 60/989,956 entitled “System and Method for False Alert Filtering of Event Messages Within a Network”, filed Nov. 25, 2007 (Attorney Docket No. TR0011-PRO); Ser. No. 60/989,975 entitled “System and Method for Network (Mesh) Layer And Application Layer Architecture And Processes,” filed Nov. 25, 2007 (Attorney Docket No. TR0014-PRO); Ser. No. 60/989,959 entitled “Tree Routing Within a Mesh Network,” filed Nov. 25, 2007 (Attorney Docket No. TR0017-PRO); Ser. No. 60/989,961 entitled “Source Routing Within a Mesh Network,” filed Nov. 25, 2007 (Attorney Docket No. TR0019-PRO); Ser. No. 60/989,962 entitled “Creating and Managing a Mesh Network,” filed Nov. 25, 2007 (Attorney Docket No. TR0020-PRO); Ser. No. 60/989,951 entitled “Network Node And Collector Architecture For Communicating Data And Method Of Communications,” filed Nov. 25, 2007 (Attorney Docket No. TR0021-PRO); Ser. No. 60/989,955 entitled “System And Method For Recovering From Head End Data Loss And Data Collector Failure In An Automated Meter Reading Infrastructure,” filed Nov. 25, 2007 (Attorney Docket No. TR0022-PRO); Ser. No. 60/989,952 entitled “System And Method For Assigning Checkpoints To A Plurality Of Network Nodes In Communication With A Device Agnostic Data Collector,” filed Nov. 25, 2007 (Attorney Docket No. TR0023-PRO); Ser. No. 60/989,954 entitled “System And Method For Synchronizing Data In An Automated Meter Reading Infrastructure,” filed Nov. 25, 2007 (Attorney Docket No. TR0024-PRO); Ser. No. 61/025,285 entitled “Outage and Restoration Notification within a Mesh Network”, filed Jan. 31, 2008 (Attorney Docket No. TR0026-PRO); Ser. No. 60/992,312 entitled “Mesh Network Broadcast,” filed Dec. 4, 2007 (Attorney Docket No. TR0027-PRO); Ser. No. 60/992,313 entitled “Multi Tree Mesh Networks”, filed Dec. 4, 2007 (Attorney Docket No. TR0028-PRO); Ser. No. 60/992,315 entitled “Mesh Routing Within a Mesh Network,” filed Dec. 4, 2007 (Attorney Docket No. TR0029-PRO); Ser. No. 61/025,279 entitled “Point-to-Point Communication within a Mesh Network”, filed Jan. 31, 2008 (Attorney Docket No. TR0030-PRO), and which are incorporated by reference. Ser. No. 61/025,270 entitled “Application Layer Device Agnostic Collector Utilizing Standardized Utility Metering Protocol Such As ANSI C12.22,” filed Jan. 31, 2008 (Attorney Docket No. TR0031-PRO); Ser. No. 61/025,276 entitled “System And Method For Real-Time Event Report Generation Between Nodes And Head End Server In A Meter Reading Network Including Form Smart And Dumb Meters,” filed Jan. 31, 2008 (Attorney Docket No. TR0032-PRO); Ser. No. 61/025,282 entitled “Method And System for Creating And Managing Association And Balancing Of A Mesh Device In A Mesh Network,” filed Jan. 31, 2008 (Attorney Docket No. TR0035-PRO); Ser. No. 61/025,271 entitled “Method And System for Creating And Managing Association And Balancing Of A Mesh Device In A Mesh Network,” filed Jan. 31, 2008 (Attorney Docket No. TR0037-PRO); Ser. No. 61/025,287 entitled “System And Method For Operating Mesh Devices In Multi-Tree Overlapping Mesh Networks”, filed Jan. 31, 2008 (Attorney Docket No. TR0038-PRO); Ser. No. 61/025,278 entitled “System And Method For Recovering From Head End Data Loss And Data Collector Failure In An Automated Meter Reading Infrastructure,” filed Jan. 31, 2008 (Attorney Docket No. TR0039-PRO); Ser. No. 61/025,273 entitled “System And Method For Assigning Checkpoints to A Plurality Of Network Nodes In Communication With A Device-Agnostic Data Collector,” filed Jan. 31, 2008 (Attorney Docket No. TR0040-PRO); Ser. No. 61/025,277 entitled “System And Method For Synchronizing Data In An Automated Meter Reading Infrastructure,” filed Jan. 31, 2008 (Attorney Docket No. TR0041-PRO); Ser. No. 61/025,285 entitled “System and Method for Power Outage and Restoration Notification in An Automated Meter Reading Infrastructure,” filed Jan. 31, 2008 (Attorney Docket No. TR0042-PRO); and Ser. No. 61/094,116 entitled “Message Formats and Processes for Communication Across a Mesh Network,” filed Sep. 4, 2008 (Attorney Docket No. TR0049-PRO).
[0032] This application hereby references and incorporates by reference each of the following United States nonprovisional patent applications filed contemporaneously herewith:
Ser. No. ______ entitled “Point-to-Point Communication within a Mesh Network”, filed Nov. 21, 2008 (Attorney Docket No. TR0004-US); Ser. No. ______ entitled “Efficient And Compact Transport Layer And Model For An Advanced Metering Infrastructure (AMI) Network,” filed Nov. 21, 2008 (Attorney Docket No. TR0003-US); Ser. No. ______ entitled “Communication and Message Route Optimization and Messaging in a Mesh Network,” filed Nov. 21, 2008 (Attorney Docket No. TR0007-US); Ser. No. ______ entitled “Collector Device and System Utilizing Standardized Utility Metering Protocol,” filed Nov. 21, 2008 (Attorney Docket No. TR0009-US); Ser. No. ______ entitled “System and Method for False Alert Filtering of Event Messages Within a Network,” filed Nov. 21, 2008 (Attorney Docket No. TR0011-US); Ser. No. ______ entitled “Method and System for Creating and Managing Association and Balancing of a Mesh Device in a Mesh Network,” filed Nov. 21, 2008 (Attorney Docket No. TR0020-US); and Ser. No. ______ entitled “System And Method For Operating Mesh Devices In Multi-Tree Overlapping Mesh Networks”, filed Nov. 21, 2008 (Attorney Docket No. TR0038-US).
FIELD OF THE INVENTION
[0040] This invention pertains generally to methods and systems for providing power outage and restoration notifications within an Advanced Metering Infrastructure (AMI) network.
BACKGROUND
[0041] A mesh network is a wireless network configured to route data between nodes within a network. It allows for continuous connections and reconfigurations around broken or blocked paths by retransmitting messages from node to node until a destination is reached. Mesh networks differ from other networks in that the component parts can all connect to each other via multiple hops. Thus, mesh networks are self-healing: the network remains operational when a node or a connection fails.
[0042] Advanced Metering Infrastructure (AMI) or Advanced Metering Management (AMM) are systems that measure, collect and analyze utility usage, from advanced devices such as electricity meters, gas meters, and water meters, through a network on request or a pre-defined schedule. This infrastructure includes hardware, software, communications, customer associated systems and meter data management software. The infrastructure allows collection and distribution of information to customers, suppliers, utility companies and service providers. This enables these businesses to either participate in, or provide, demand response solutions, products and services. Customers may alter energy usage patterns from normal consumption patterns in response to demand pricing. This improves system load and reliability.
[0043] A meter may be installed on a power line, gas line, or water line and wired into a power grid for power. During an outage, the meter may cease to function. When power is restored, meter functionality may be restored.
SUMMARY
[0044] A method and system provide power outage and restoration notifications within an AMI network. Mesh networks are used to connect meters of an AMI in a geographical area. Each meter may communicate with its neighbors via the mesh network. A mesh gate links the mesh network to a server over a wide area network (WAN). When a power outage occurs among the meters of a mesh network, leaf meters transmit outage messages first. Parent meters add a parent identifier before forwarding the outage messages. This reduces the number of transmitted outage messages within the mesh network. Similarly, restoration messages are transmitted from the leaf nodes first, while parent nodes piggy-back parent identifiers when forwarding the restoration messages from the leaf meters.
[0045] In one aspect, there is provided a system and method for power outage and restoration notification in an advanced metering infrastructure network.
[0046] In another aspect, there is provided a method of transmitting a meter power status, including: recognizing a power status change at a meter; if the meter is scheduled to transmit first, transmitting a notification message to at least one neighboring meter towards a mesh gate, wherein the notification message includes a power status indicator and a meter identifier; if the meter is not scheduled to transmit first, waiting a predetermined time period to receive a notification message from at least one neighboring meter; responsive to receiving a notification message, adding a meter identifier to the received notification message before retransmitting the modified notification message to at least one neighboring meter; and retransmitting the notification message.
[0047] In another aspect, there is provided a method of transmitting a network power status, including: receiving at least one notification message from a meter, wherein the notification message includes a power status indicator and at least one meter identifier; aggregating the received meter identifiers into a composite notification message, the composite notification message including a power status indicator and at least one meter identifier; transmitting the composite notification message to a server over a wide area network; and retransmitting the composite notification message.
[0048] In another aspect, there is provided a system for transmitting a network power status, including: (A) a mesh network; (B) a wide area network separate from the mesh network; (C) at least one meter in communication with the mesh network, the meter configured to: recognize a power status change at a meter, if the meter is scheduled to transmit first, transmit a notification message to at least one neighboring meter towards a mesh gate, wherein the notification message includes a power status indicator and a meter identifier, if the meter is not scheduled to transmit first, wait a predetermined time period to receive a notification message from at least one neighboring meter, responsive to receiving a notification message, adding a meter identifier to the received notification message before retransmitting the modified notification message to at least one neighboring meter, and retransmitting the notification message; (D) a mesh gate in communication with the meter over the mesh network and in communication with the wide area network, the mesh gate configured to: receive at least one notification message from a meter, wherein the notification messages include a power status indicator and at least one meter identifier, aggregate the received meter identifiers into a composite notification message, the composite notification message includes a power status indicator and at least one meter identifier, transmit the composite notification message to a server over a wide area network, and retransmitting the composite notification message; and (E) a server in communication with the mesh gate over the wide area network, the server configured to receive the composite notification message.
[0049] In another aspect, there is provided a system for transmitting a network power status, including: a mesh network; a wide area network separate from the mesh network; at least one meter in communication with the mesh network; a mesh gate in communication with the meter over the mesh network and in communication with the wide area network; and a server in communication with the mesh gate over the wide area network, the server configured to receive the composite notification message.
[0050] In another aspect, there is provided a computer program stored in a computer readable form for execution in a processor and a processor coupled memory to implement a method of transmitting a meter power status, the method including: recognizing a power status change at a meter; if the meter is scheduled to transmit first, transmitting a notification message to at least one neighboring meter towards a mesh gate, wherein the notification message includes a power status indicator and a meter identifier; if the meter is not scheduled to transmit first, waiting a predetermined time period to receive a notification message from at least one neighboring meter; responsive to receiving a notification message, adding a meter identifier to the received notification message before retransmitting the modified notification message to at least one neighboring meter; and retransmitting the notification message.
[0051] In another aspect, there is provided a computer program stored in a computer readable form for execution in a processor and a processor coupled memory to implement a method of transmitting a network power status, including: receiving at least one notification message from a meter, wherein the notification message includes a power status indicator and at least one meter identifier; aggregating the received meter identifiers into a composite notification message, the composite notification message including a power status indicator and at least one meter identifier; transmitting the composite notification message to a server over a wide area network; and retransmitting the composite notification message.
[0052] In another aspect, there is provided a method of transmitting a meter power status, including: recognizing a power status change at a meter; if the meter is scheduled to transmit first, transmitting a notification message from the meter to at least one neighboring meter towards a mesh gate, wherein the notification message includes a power status indicator and a meter identifier; if the meter is not scheduled to transmit first, waiting a predetermined time period to receive a notification message from at least one neighboring meter; responsive to receiving a notification message, adding a meter identifier to the received notification message before retransmitting the modified notification message to at least one neighboring meter, wherein the notification message includes a power status indicator and at least one meter identifier; aggregating the received meter identifiers into a composite notification message, the composite notification message including a power status indicator and at least one meter identifier; transmitting the composite notification message to a server over a wide area network; and retransmitting the composite notification message.
[0053] In another aspect, there is provided a computer program stored in a computer readable form for execution in a processor and a processor coupled memory to implement a method of transmitting a meter power status, the method including: recognizing a power status change at a meter; if the meter is scheduled to transmit first, transmitting a notification message from the meter to at least one neighboring meter towards a mesh gate, wherein the notification message includes a power status indicator and a meter identifier; if the meter is not scheduled to transmit first, waiting a predetermined time period to receive a notification message from at least one neighboring meter; responsive to receiving a notification message, adding a meter identifier to the received notification message before retransmitting the modified notification message to at least one neighboring meter, wherein the notification message includes a power status indicator and at least one meter identifier; aggregating the received meter identifiers into a composite notification message, the composite notification message including a power status indicator and at least one meter identifier; transmitting the composite notification message to a server over a wide area network; and retransmitting the composite notification message.
[0054] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0055] FIG. 1 illustrates an example system for providing AMI communications over a mesh network.
[0056] FIG. 2A illustrates an example meter for use within a mesh network.
[0057] FIG. 2B illustrates an example mesh gate for use within a mesh network.
[0058] FIG. 3 illustrates an example network stack for use within a mesh radio.
[0059] FIG. 4A illustrates an example procedure for transmitting outage and restoration notifications from a meter within a mesh network.
[0060] FIG. 4B illustrates an example procedure for transmitting outage and restoration notifications from a mesh gate within a wide area network.
[0061] FIG. 5A illustrates a first timing of transmitting outage notifications from a meter within a mesh network.
[0062] FIG. 5B illustrates a second timing of transmitting outage notifications from a meter within a mesh network.
[0063] FIG. 6 illustrates a timing of transmitting restoration notifications from a meter within a mesh network.
DETAILED DESCRIPTION
[0064] FIG. 1 illustrates an example system for providing AMI communications over a mesh network. A mesh network A 100 may include a mesh gate A 102 and a plurality of meters: meters A 104 , B 106 , C 108 , D 110 , E 112 , and F 114 . A mesh gate may also be referred to as a NAN-WAN gate or an access point. The mesh gate A 102 may communicate to a server 118 over a wide area network 116 . Optionally, a mesh gate B 120 and a mesh network B 122 may also communicate with the server 118 over the wide area network (WAN) 116 . Optionally, a mesh gate C 124 and a mesh network C 126 may also communicate with the server 118 over the wide area network 116 .
[0065] In one example embodiment, the server 118 is known as a “head end.” The mesh gate may also be known as a collector, a concentrator, or an access point.
[0066] It will be appreciated that a mesh device association can include a registration for application service at the mesh gate A 102 or the server 118 . The mesh gate A 102 and the server 118 can maintain a table of available applications and services and requesting mesh devices.
[0067] The mesh network A 100 may include a plurality of mesh gates and meters which cover a geographical area. The meters may be part of an AMI system and communicate with the mesh gates over the mesh network. For example, the AMI system may monitor utilities usage, such as gas, water, or electricity usage and usage patterns.
[0068] The mesh gate A 102 may provide a gateway between the mesh network A 100 and a server, discussed below. The mesh gate A 102 may include a mesh radio to communicate with the mesh network A 100 and a WAN communication interface to communicate with a WAN.
[0069] The mesh gate A 102 may aggregate information from meters within the mesh network A 100 and transmit the information to the server. The mesh gate A 102 may be as depicted below. It will be appreciated that while only one mesh gate is depicted in the mesh network A 100 , any number of mesh gates may be deployed within the mesh network A 100 , for example, to improve transmission bandwidth to the server and provide redundancy. A typical system will include a plurality of mesh gates within the mesh network. In a non-limiting embodiment for an urban or metropolitan geographical area, there may be between 1 and 100 mesh gates, though this is not a limitation of the invention. In one embodiment, each mesh gate supports approximately 400 meters, depending on system requirements, wireless reception conditions, available bandwidth, and other considerations. It will be appreciated that it is preferable to limit meter usage of bandwidth to allow for future upgrades.
[0070] The meters A 104 , B 106 , C 108 , D 110 , E 112 , and F 114 may each be a mesh device, such as a meter depicted below. The meters may be associated with the mesh network A 100 through direct or indirect communications with the mesh gate A 102 . Each meter may forward or relay transmissions from other meters within the mesh network A 100 towards the mesh gate A. It will be appreciated that while only six meters are depicted in the mesh network A 100 , any number of meters may be deployed to cover any number of utility lines or locations.
[0071] As depicted, only meters A 104 and D 110 are in direct communications with mesh gate A 102 . However, meters B 106 , E 112 and F 114 can all reach mesh gate A 102 through meter D 110 . Similarly, meter C 108 can reach mesh gate A 102 through meter E 112 and meter D 110 .
[0072] The wide area network (WAN) 116 may be any communication medium capable of transmitting digital information. For example, the WAN 116 may be the Internet, a cellular network, a private network, a phone line configured to carry a dial-up connection, or any other network.
[0073] The server 118 may be a computing device configured to receive information from a plurality of mesh networks and meters. The server 118 may also be configured to transmit instructions to the mesh networks, mesh gates, and meters.
[0074] It will be appreciated that while only one server is depicted, any number of servers may be used in the AMI system. For example, servers may be distributed by geographical location. Redundant servers may provide backup and failover capabilities in the AMI system.
[0075] The optional mesh gates B 120 and C 124 may be similar to mesh gate A 102 , discussed above. Each mesh gate may be associated with a mesh network. For example, mesh gate B 120 may be associated with mesh network B 122 and mesh gate C 124 may be associated with mesh network C 126 .
[0076] The mesh network B 122 and the mesh network C 126 may be similar to the mesh network A 102 . Each mesh network may include a plurality of meters (not depicted).
[0077] Each mesh network may cover a geographical area, such as a premise, a residential building, an apartment building, or a residential block. Alternatively, the mesh network may include a utilities network and be configured to measure utilities flow at each sensor. Each mesh gate communicates with the server over the WAN, and thus the server may receive information from and control a large number of meters or mesh devices. Mesh devices may be located wherever they are needed, without the necessity of providing wired communications with the server.
[0078] FIG. 2A illustrates an example meter for use within a mesh network. A meter 200 may include a radio 202 , a communication card 204 , a metering sensor 206 , and a battery or other power or energy storage device or source 208 . The radio 202 may include a memory 210 , a processor 212 , a transceiver 214 , and a microcontroller unit (MCU) 216 or other processor or processing logic.
[0079] A mesh device can be any device configured to participate as a node within a mesh network. An example mesh device is a mesh repeater, which can be a wired device configured to retransmit received mesh transmissions. This extends a range of a mesh network and provides mesh network functionality to mesh devices that enter sleep cycles.
[0080] The meter 200 may be a mesh device communicating with a mesh gate and other mesh devices over a mesh network. For example, the meter 200 may be a gas, water or electricity meter installed in a residential building or other location to monitor utilities usage. The meter 200 may also control access to utilities on server instructions, for example, by reducing the flow of gas, water or electricity.
[0081] The radio 202 may be a mesh radio configured to communicate with a mesh network. The radio 202 may transmit, receive, and forward messages to the mesh network. Any meter within the mesh network may thus communicate with any other meter or mesh gate by communicating with its neighbor and requesting a message be forwarded.
[0082] The communication card 204 may interface between the radio 202 and the sensor 206 . Sensor readings may be converted to radio signals for transmission over the radio 202 . The communication card 204 may include encryption/decryption or other security functions to protect the transmission. In addition, the communication card 204 may decode instructions received from the server.
[0083] The metering sensor 206 may be a gas, water, or electricity meter sensor, or another sensor. For example, digital flow sensors may be used to measure a quantity of utilities consumed within a residence or building. Alternatively, the sensor 206 may be an electricity meter configured to measure a quantity of electricity flowing over a power line.
[0084] The battery 208 may be configured to independently power the meter 200 during a power outage. For example, the battery 208 may be a large capacitor storing electricity to power the meter 200 for at least five minutes after a power outage. Small compact but high capacity capacitors known as super capacitors are known in the art and may advantageously be used. One exemplary super capacitor is the SESSCAP 50 f 2.7 v 18×30 mm capacitor. Alternative battery technologies may be used, for example, galvanic cells, electrolytic cells, fuel cells, flow cells, and voltaic cells.
[0085] It will be appreciated that the radio 202 , communication card 204 , metering sensor 206 and battery 208 may be modular and configured for easy removal and replacement. This facilitates component upgrading over a lifetime of the meter 200 .
[0086] The memory 210 of the radio 202 may store instructions and run-time variables of the radio 202 . For example, the memory 210 may include both volatile and non-volatile memory.
[0087] The memory 210 may also store a history of sensor readings from the metering sensor 206 and an incoming queue of server instructions.
[0088] The processor 212 of the radio 202 may execute instructions, for example, stored in memory 210 . Instructions stored in memory 210 may be ordinary instructions, for example, provided at time of meter installation, or special instructions received from the server during run time.
[0089] The transceiver 214 of the radio 202 may transmit and receive wireless signals to a mesh network. The transceiver 214 may be configured to transmit sensor readings and status updates under control of the processor 212 . The transceiver 214 may receive server instructions from a server, which are communicated to the memory 210 and the processor 212 .
[0090] In the example of FIG. 2A , the MCU 216 can execute firmware or software required by the meter 200 . The firmware or software can be installed at manufacture or via a mesh network over the radio 202 .
[0091] In one embodiment, any number of MCUs can exist in the meter 200 . For example, two MCUs can be installed, a first MCU for executing firmware handling communication protocols, and a second MCU for handling applications.
[0092] It will be appreciated that a mesh device and a mesh gate can share the architecture of meter 200 . The radio 202 and the MCU 216 provide the necessary hardware, and the MCU 216 executes any necessary firmware or software.
[0093] Meters may be located in geographically dispersed locations within an AMI system. For example, a meter may be located near a gas line, an electric line, or a water line entering a building or premise to monitor a quantity of gas, electricity, or water. The meter may communicate with other meters and mesh gates through a mesh network. The meter may transmit meter readings and receive instructions via the mesh network.
[0094] FIG. 2B illustrates an example mesh gate for use within a mesh network. The mesh gate 230 may include a mesh radio 232 , a wide area network interface 234 , a battery 236 , and a processor 238 . The mesh radio 232 may include a memory 242 , a processor 244 , and a transceiver 246 .
[0095] The mesh gate 230 may interface between mesh devices (for example, meters) in a mesh network and a server. For example, meters may be as discussed above. The mesh gate 230 may be installed in a central location relative to the meters and also communicate with a server over a WAN.
[0096] The mesh radio 232 may be a mesh radio configured to communicate with meters over a mesh network. The radio 232 may transmit, receive, and forward messages to the mesh network.
[0097] The WAN interface 234 may communicate with a server over a WAN. For example, the WAN may be a cellular network, a private network, a dial up connection, or any other network. The WAN interface 234 may include encryption/decryption or other security functions to protect data being transmitted to and from the server.
[0098] The battery 236 may be configured to independently power the mesh gate 230 during a power outage. For example, the battery 236 may be a large capacitor storing electricity to power the mesh gate 230 for at least five minutes after a power outage. A power outage notification process may be activated during a power outage.
[0099] The processor 238 may control the mesh radio 232 and the WAN interface 234 . Meter information received from the meters over the mesh radio 232 may be compiled into composite messages for forwarding to the server. Server instructions may be received from the WAN interface 234 and forwarded to meters in the mesh network.
[0100] It will be appreciated that the mesh radio 232 , WAN interface 234 , battery 236 , and processor 238 may be modular and configured for easy removal and replacement. This facilitates component upgrading over a lifetime of the mesh gate 230 .
[0101] The memory 242 of the mesh radio 232 may store instructions and run-time variables of the mesh radio 232 . For example, the memory 242 may include both volatile and non-volatile memory. The memory 242 may also store a history of meter communications and a queue of incoming server instructions. For example, meter communications may include past sensor readings and status updates.
[0102] The processor 244 of the mesh radio 232 may execute instructions, for example, stored in memory 242 . Instructions stored in memory 242 may be ordinary instructions, for example, provided at time of mesh gate installation, or special instructions received from the server during run-time.
[0103] The transceiver 246 of the mesh radio 232 may transmit and receive wireless signals to a mesh network. The transceiver 246 may be configured to receive sensor readings and status updates from a plurality of meters in the mesh network. The transceiver 246 may also receive server instructions, which are communicated to the memory 242 and the processor 244 .
[0104] A mesh gate may interface between a mesh network and a server. The mesh gate may communicate with meters in the mesh network and communicate with the server over a WAN network. By acting as a gateway, the mesh gate forwards information and instructions between the meters in its mesh network and the server.
[0105] FIG. 3 illustrates an example network stack for use within a mesh radio. A radio 300 may interface with an application process 302 . The application process 302 may communicate with an application layer 304 , which communicates with a transport layer 306 , a network layer 308 , a data link layer 310 and a physical layer 312 .
[0106] The radio 300 may be a mesh radio as discussed above. For example, the radio 300 may be a component in a meter, a mesh gate, or any other mesh device configured to participate in a mesh network. The radio 300 may be configured to transmit wireless signals over a predetermined frequency to other radios.
[0107] The application process 302 may be an executing application that requires information to be communicated over the network stack. For example, the application process 302 may be software supporting an AMI system.
[0108] The application layer 304 interfaces directly with and performs common application services for application processes. Functionality includes semantic conversion between associated application processes. For example, the application layer 304 may be implemented as ANSI C12.12/22.
[0109] The transport layer 306 responds to service requests from the application layer 304 and issues service requests to the network layer 308 . It delivers data to the appropriate application on the host computers. For example, the layer 306 may be implemented as TCP (Transmission Control Protocol), and UDP (User Datagram Protocol).
[0110] The network layer 308 is responsible for end to end (source to destination) packet delivery. The functionality of the layer 308 includes transferring variable length data sequences from a source to a destination via one or more networks while maintaining the quality of service, and error control functions. Data will be transmitted from its source to its destination, even if the transmission path involves multiple hops.
[0111] The data link layer 310 transfers data between adjacent network nodes in a network, wherein the data is in the form of packets. The layer 310 provides functionality including transferring data between network entities and error correction/detection. For example, the layer 310 may be implemented as IEEE 802.15.4.
[0112] The physical layer 312 may be the most basic network layer, transmitting bits over a data link connecting network nodes. No packet headers or trailers are included. The bit stream may be grouped into code words or symbols and converted to a physical signal, which is transmitted over a transmission medium, such as radio waves. The physical layer 312 provides an electrical, mechanical, and procedural interface to the transmission medium. For example, the layer 312 may be implemented as IEEE 802.15.4.
[0113] The network stack provides different levels of abstraction for programmers within an AMI system. Abstraction reduces a concept to only information which is relevant for a particular purpose. Thus, each level of the network stack may assume the functionality below it on the stack is implemented. This facilitates programming features and functionality for the AMI system.
[0114] FIG. 4A illustrates an example procedure for transmitting outage and restoration notifications from a meter within a mesh network. A mesh device, such as a meter, may include a sensor for measuring utilities and receive power from a power grid. At times, the power grid may fail during a power outage. The power grid may also be restored after an outage. The meter may include a battery configured to power the meter for a period of time, during which the meter executes a power outage notification procedure to inform a mesh gate and a server of the power outage. Similarly, the meter may execute a power restoration notification when functionality is restored after power is restored to the power grid.
[0115] In 400 , the meter may detect a power status change. For example, the meter may include an electric sensor sensing a power, current, or voltage of an electric line powering the meter from a power grid. When the sensor senses a cut-off in electricity, the meter may wait a predetermined recognition period before determining that a power outage has occurred.
[0116] When a meter's power is restored after an outage, the meter may also wait a predetermined recognition period before determining that the power outage has ended and power has been restored. Using a recognition period before an outage or a restoration has occurred prevents the meter from trigging the notification procedure for brief outages and restorations.
[0117] In 402 , the meter tests whether it is the first to transmit. For example, the meter may look up a neighborhood table to determine whether it is a leaf meter. A leaf meter may have no children meters, and is thus the last meter on its associated branch. For example, FIG. 1 depicts meters A 104 , B 106 , C 108 , and F 114 as leaf meters. Meter F 114 is a leaf meter because no child meter would transmit through it to reach mesh gate A 102 , even though meter F 114 has two alternate paths to the mesh gate A 102 (F 114 to E 112 to D 110 to mesh gate or F 114 to D 110 to mesh gate).
[0118] A one-hop device, which can be a device in direct communications with the mesh gate, may transmit immediately.
[0119] Alternatively, the meter may look up the neighborhood table to determine a number of hops to the mesh gate. If it is farthest from the mesh gate on its branch, it will transmit first. If the meter determines yes, the meter proceeds to 404 . If no, the meter proceeds to 410 . The neighborhood table can be built during association requests and subsequent neighbor exchanges.
[0120] In 404 , the meter may transmit a notification message. The notification message may include a nature of the notification (whether a power outage or restoration has occurred, as determined in 400 ) and a meter identifier. The meter identifier may be a globally unique identifier assigned to the meter at manufacture or installation that identifies the meter to the mesh gate and the server.
[0121] If the notification message has previously been transmitted, the meter may attempt a retry transmission. Retries may be attempted until an acknowledgement is received or a predetermined number of retry attempts has been exceeded.
[0122] Information transmitted in the transmission may include a device identifier, a time of outage, and any other necessary information. In one embodiment, a number of transmitted neighbor information may be restricted. For example, only a predetermined maximum number of parents, siblings, and children node information can be transmitted to limit message size. Neighbors can be selected based on a preferred route ratio. Neighbors that are on a preferred route of a meter's path to the mesh gate may be prioritized. The preferred route ratio can be used to select routes with a minimum of hops over a best minimum signal quality link to the mesh gate.
[0123] In 406 , the meter may test whether it has exceeded a predetermined retry attempts. The meter may increment a counter for a number of retries after every attempt to transmit a notification message in 404 . The predetermined retry attempts may be set to limit network congestion, both within the mesh network and over a WAN from a mesh gate to the server during a power outage and restoration.
[0124] Alternatively, the meter may continually attempt to transmit until its battery is drained during a power outage notification procedure. This may be used in an AMI system where it is important to receive as many accurate outage notifications as possible, or where network bandwidth is of lesser concern. If the predetermined retry attempts have been exceed, the procedure ends. If no, the meter procedures to 408 .
[0125] In 408 , the meter optionally delays a random time period. For example, the delay may allow other meters in the mesh network to transmit and reduce collisions. Further, the delay may improve battery life after a power outage.
[0126] The random time period may be associated with a predetermined floor value, below which it cannot be set. This may be an exclusion period during which no retransmission may be attempted by the meter.
[0127] In 410 , the meter tests whether a child message has been received. For example, a non-leaf meter will not transmit during a first attempt, and may receive notification messages from child meters. If yes, the meter proceeds to 412 . If no, the meter proceeds to 404 . In one embodiment, if the meter determines it has missed the child messages, it may immediately transmit its message.
[0128] In 412 , the meter may insert a meter identifier in the notification message. The notification message received from the child meter in 410 may include a status (whether the notification is for a power outage or restoration) and at least one meter identifier associated with children meters. The meter may insert its own identifier into the message before forwarding the message in 404 .
[0129] By executing the procedure above, leaf meters transmit notification messages first. Each meter waits to receive a notification message from children meters before adding its identifier and forwarding the notification to its parent meter. This reduces message congestion in the mesh network during a notification procedure.
[0130] In an alternative example, each parent meter may determine how many children meters it has, and wait for notification messages from all children meters before compiling the messages into one message to be forwarded. Alternatively, the parent meter may wait for a predetermined period of time, because only some children meters may be affected by a power outage.
[0131] It will be appreciated that if a meter has not suffered a power outage, it would simply forward any received notification messages to its parent without adding its identifier into the message. Similarly, if a parent meter has not had a power restoration; it will remain off and be unable to forward notification messages. In this example, children meters may attempt alternative routes to transmit notification messages, as discussed below.
[0132] FIG. 4B illustrates an example procedure for transmitting outage and restoration notifications from a mesh gate within a wide area network. A mesh gate and its associated mesh devices, such as meters, may receive power from a power grid. At times, the power grid may fail during a power outage. The power grid may also be restored after an outage. The mesh gate may include a battery configured to power the mesh gate for a period of time, during which the mesh gate executes a power outage notification procedure to inform a server of the outage and affected meters. Similarly, the mesh gate may execute a power restoration notification when power is restored to the power grid.
[0133] In 450 , the mesh gate may receive a notification message from a meter within its mesh network. For example, the notification message may include a status indicating whether it is an outage or restoration notification and at least one meter identifier. The notification message may be as discussed above.
[0134] In 452 , the mesh gate may test whether it has finished receiving notification messages from the mesh network. For example, the mesh gate may continually receive notification messages until its battery drops to a critical level during an outage. The critical level may be set to where enough power remains in the battery to allow the mesh gate to transmit its composite notification message to the server, as discussed below, along with a predetermined number of retries.
[0135] Alternatively, the mesh gate may wait for a predetermined time period after receiving a first notification message. For example, the predetermined time period may be determined, in part, based on the size of the mesh network, the maximum number of hops to reach a leaf meter, the link quality of the mesh network, etc.
[0136] Alternatively, the mesh gate may proceed as soon as message notifications from all children meters within the mesh network have been received. If all children meters are accounted for, the mesh gate does not need to wait for further notification messages.
[0137] If the mesh gate has finished receiving notification messages, it may proceed to 454 . If no, it may proceed to 450 to await more notification messages.
[0138] In 454 , the mesh gate may select a power reporting configuration. For example, two power reporting configurations may be available: one used for minor outage, such as one affecting only a few meters, and one used for major outages, such as one affecting many meters. The power reporting configuration may affect the retry attempts and delay periods discussed below.
[0139] For example, it may be very important to inform the server of a major outage. Thus, a high number of retry attempts may be set. It may be likely that a major outage has affected other mesh networks. Thus, a longer delay period may be used to reduce transmission collisions over the WAN. In addition, a longer window may be set to wait for notification messages from meters.
[0140] In 456 , the mesh gate may aggregate all the notification messages into a composite notification message. For example, the mesh gate may create the composite notification message containing a status indicating whether an outage or restoration has occurred in the mesh network and a list of meter identifiers associated with the notification. For example, the list of meter identifiers may be received in 452 from one or more meters.
[0141] In one example, the mesh gate may receive both an outage and a restoration notification message. The mesh gate may aggregate a first notification message, for example, all received outage notification messages, for transmission. Then, the mesh gate may aggregate a second notification message, for example, the restoration notification message for transmission.
[0142] In 458 , the mesh gate may transmit the composite notification message to the server over a WAN. For example, the WAN may be a cellular network, a wired network, or another network configured to carry information. In one example, the WAN used to transmit the composite notification message may be a secondary communications medium. A primary wired network may fail during a power outage, and therefore a backup network may be used. For example, the backup network may be a battery-powered network, cellular network, a battery-powered wired network, or another network configured to operate during an outage.
[0143] If the composite notification message has previously been transmitted, the mesh gate may attempt a retry transmission. Retries may be attempted until an acknowledgement is received or a predetermined number of retry attempts has been exceeded.
[0144] In 460 , the mesh gate may test whether a predetermined number of retry attempts has been exceeded. The mesh gate may increment a counter for a number of retries after every attempt to transmit a notification message in 458 . The predetermined retry attempts may be set to limit network congestion over the WAN to the server during a power outage and restoration.
[0145] Alternatively, the mesh gate may continually attempt to transmit until its battery is drained during a power outage notification procedure. This may be used in an AMI system where it is important to receive as many accurate outage notifications as possible, or where network bandwidth is of lesser concern.
[0146] For example, the predetermined number of retry attempts may be set in part based on the power reporting configuration selected in 454 . If the predetermined number of retry attempts has been exceeded, the mesh gate may end the procedure. If no, the mesh gate may proceed to 462 .
[0147] In 462 , the mesh gate may optionally delay a random time period. For example, the delay may allow other mesh gates in the WAN to transmit and reduce collisions. Further, the delay may improve battery life after a power outage.
[0148] For example, the delay period may be set in part based on the power reporting configuration selected in 454 . The random time period may be associated with a floor value, below which it cannot be set. This may be an exclusion period during which no retransmission may be attempted.
[0149] The mesh gate may aggregate all notification messages sent to it by meters over the mesh network. The composite notification message consists of a power status and a list of meter identifiers identifying the meters affected by the power status. The composite notification message may be transmitted over an outage-resistant communications link to a server.
[0150] FIG. 5A illustrates a first timing of transmitting outage notifications from a meter within a mesh network. A power outage notification process allows orderly transmission of power outage notification from one or more mesh devices (such as a meter) in a mesh network to a mesh gate. The mesh gate aggregates the notifications and transmits a composite message to a server. Because the mesh network may include a large number of meters, transmitting individual notifications from each meter may cause network congestion, especially because other meters within the mesh network are also likely affected by the same outage and will also be sending outage notifications.
[0151] A recognition period (e.g., RECOGNITION_PERIOD) may elapse between an occurrence of a power outage and time T 1 , when the power outage is recognized by the meter. The recognition period may prevent minor power fluctuations or outages from triggering the outage notification procedure.
[0152] FIG. 5B illustrates a second timing of transmitting outage notifications from a meter within a mesh network. The meter may wait for a first random period before a first attempt to send a power outage notification at time T 2 . A first attempt wait period (e.g., PO_RND_PERIOD) may represent a maximum random delay in seconds used before the first attempt. This random delay starts after recognition period (RECOGNITION_PERIOD) elapses at time T 1 . The first attempt is reserved for leaf meters. A meter which is not a leaf meter will not transmit during the first attempt.
[0153] The meter may wait for a retry random period before a retry attempt at time T 3 . A retry wait period (e.g., PO_RETRY_RND_PERIOD) may represent a maximum random delay in seconds used for each retry. This random delay starts after time T 2 , when a first transmission attempt occurs.
[0154] Using a random delay before the first and retry attempts prevents colliding transmission from multiple meters and reduces network congestion. If a meter attempts to transmit but a transmission is already in progress, the meter may wait for the transmission in progress to end before attempting to transmit.
[0155] If a meter receives a notification from a child meter, its transmission includes the child's notification plus the meter's identifier. By piggy-backing the meter's identifier in a child's notification and forwarding the notification, the number of individual notifications and messages are reduced in the mesh network.
[0156] The meter may continually retry to transmit an outage notification until the meter's battery is drained. In addition, there may be a predetermined maximum number retries. In addition, there may be a minimum period for the first delay and the subsequent retry delays. The minimum delay periods may eliminate the possibility of immediate retransmissions and guarantee a minimum delay between attempts.
[0157] The mesh gate may receive all the power outage notification messages and compile the information into a message for transmission to a server over a WAN. The mesh gate may also retransmit the compiled notification as necessary, until its battery is drained.
[0158] Child meters in a mesh network transmit outage notifications first, and parent meters piggy-back meter identifiers into the child notifications before forwarding the child notifications. A number of messages and notifications transmitted in the mesh network during an outage are thereby reduced.
[0159] FIG. 6 illustrates a timing of transmitting restoration notifications from a meter within a mesh network. A power restoration notification process allows orderly transmission of power restoration notification messages from one or more mesh devices (such as a meter) in a mesh network to a mesh gate. The mesh gate aggregates the notifications and transmits a composite message to a server. Because the mesh network may include a large number of meters, transmitting individual notifications from each meter may cause network congestion, especially because other meters within the mesh network are also likely affected by the restoration and will also be sending restoration notifications.
[0160] When power is restored at a meter, the meter may first wait for a recognition period before deciding the power has been restored. The recognition period may prevent triggering restoration notifications when power returns for a brief moment before the outage continues.
[0161] A first random period, PR_RND_PERIOD, may represent a maximum random delay used before a first attempt is made to send a power restoration notification. This first random period may begin after the power restored recognition period, PR_RECOGNITION_PERIOD. A first notification may be transmitted. Only leaf meters transmit during the first attempt.
[0162] A retry random period, PR_RETRY_RND_PERIOD, may represent a maximum random delay before a retry to send a power restoration notification. The retry random period begins after the first random period.
[0163] Using a random delay before the first and retry attempts reduces colliding transmission from multiple meters. If a meter attempts to transmit but a transmission is already in progress, the meter may wait for the transmission to end before attempting to transmit.
[0164] After the first attempt to transmit has been made, the mesh gate may wait a minimum delay (e.g., MIN_DELAY) to time T 4 and an additional random period (e.g., RAND_PERIOD) to time T 5 before retrying transmission. Each retry attempt may be preceded by a retry random period (e.g., RETRY_RND_PERIOD) to time T 6 , and a maximum number of retry attempts may be set at maximum retries (e.g., MAX_RETRIES). The procedure may stop at time T 7 , after all retry attempts have been made.
[0165] If a meter receives a notification from a child meter, its transmission includes the child's notification plus the meter's identifier. By piggy-backing the meter's identifier in a child's notification and forwarding the notification, the number of individual notifications and messages are reduced in the mesh network.
[0166] The mesh gate may receive all power restoration notification messages and compile the information into a composite message for transmission to a server over a WAN. Similarly, the mesh gate may also repeatedly attempt to transmit the composite restoration message until a maximum number of retries have been made or the server acknowledges the transmission.
[0167] Child meters in a mesh network transmit restoration notifications first, and parent meters piggy-back meter identifiers into the child notifications before forwarding the child notifications. A number of messages and notifications transmitted in the mesh network during a restoration are thereby reduced.
[0168] If a child meter attempts to forward a message to a parent meter that is not functional (for example, the parent meter's power has not been restored); the child meter may wait a predetermined period of time. If the parent meter remains non-functional, the child meter may attempt to send its notification via an alternative path through the mesh network stored in its memory. If that fails, the child meter may attempt to discover a new route through the mesh network to the mesh gate. If that fails, the child meter may attempt to associate with a new mesh network in order to transmit its restoration notification message.
[0169] Although the above embodiments have been discussed with reference to specific example embodiments, it will be evident that the various modification, combinations and changes can be made to these embodiments. Accordingly, the specification and drawings are to be regarded in an illustrative sense rather than in a restrictive sense. The foregoing specification provides a description with reference to specific exemplary embodiments. It will be evident that various modifications may be made thereto without departing from the broader spirit and scope as set forth in the following claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense. | A method and system are provided to transmit a meter power status. The method includes recognizing a power status change at a meter. The method includes, if the meter is scheduled to transmit first, transmitting a notification message to at least one neighboring meter towards a mesh gate, wherein the notification message includes a power status indicator and a meter identifier. The method includes, if the meter is not scheduled to transmit first, waiting a predetermined time period to receive a notification message from at least one neighboring meter. The method includes, responsive to receiving a notification message, adding a meter identifier to the received notification message before retransmitting the modified notification message to at least one neighboring meter. The method includes retransmitting the notification message. | 8 |
BACKGROUND OF THE INVENTION
Bisphenol A, 2,2'-bis(4-hydroxyphenyl)propane*, is widely used in the manufacture of epoxy resins and polycarbonates. Bisphenol A is usually prepared by the condensation of phenol and acetone in the presence of an acid catalyst with a sulfur-containing promoter. However, the reaction between phenol and acetone to form 2,2'-bis(4-hydroxyphenyl)propane using any known catalyst always produces a number of by-products. It is well known that the purity of bisphenol A is very important with regard to the quality of polymers which are prepared therefrom. In the production of polycarbonates, bisphenol A purity requirement is much higher than that of the product obtained by any production method without further purification. Typical commercial bisphenol was found to contain 4% o,p'-isomer, 3% trisphenol I and 1% Dianins compound (Anal. Chem. 31, 1214-17, 1959). There are many patents related to the purification of bisphenol; and the extent of the purification necessary is dependent on yield, crude bisphenol purity, and quality of final product desired. One method suggested is the formation of a 1:1 crystalline complex with phenol (U.S. Pat. No. 2,791,616). The phenol complex may be refined by washing with phenol, after which it is remelted and heated under vacuum to decompose the complex and distill out the phenol.
A number of suggested processes describe merely leaching crude bisphenol with a solvent or mixture of solvents selected to dissolve maximum amounts of by-products and minimum amounts of bisphenol. However, the bisphenol obtained from such solvent leaching normally is not pure enough for polycarbonate production. The bisphenol can also be purified by a combination of vacuum distillation and solvent leaching techniques (U.S. Pat. Nos. 3,219,549 and 3,290,391). More complicated, but more effective methods involve crystallization from an organic solvent at a temperature and pressure above the atmospheric boiling point of the solvent (U.S. Pat. No. 3,673,262). In yet another process for purification of bisphenols, a mixture of the reaction product, water and a water immiscible organic solvent is heated to a temperature below the boiling point of the organic solvent to provide two liquid phases which are then cooled to crystallize the bisphenol (U.S. Pat. No. 3,535,389). U.S. Pat. No. 3,326,986 employs a similar process in which the crude bisphenol is heated and melted in water without any organic solvent. The melt is agitated, then cooled and the crystals washed with a chlorinated organic solvent, e.g., methylene chloride, to remove the impurities.
Recovery of the purified product by the crystallization procedure varies from about 50 percent to a rarely achieved 90 percent which adds considerably to the cost of the bisphenol product finally obtained. It is well known that the final product purity is inversely related to the yield. Higher product purity will give lower yield. Most literature on bisphenol purification through crystallization emphasizes the final product purity and neglects the product yield. Known processes provide a yield of from 50-95% of the desired p,p'-bis product. The most effective method to increase the yield is to convert the by-products in the residue back to useful bisphenol through acid-catalyzed rearrangement or isomerization in a phenol medium. In order to make such isomerization feasible, the by-product concentration in such residual streams has to be very high. It is an object of this invention to provide a bisphenol purification process with a high yield and a high purity final product. The ultimate object of this invention is to provide an efficient process for the production of high purity 2,2'-bis(4-hydroxyphenyl)propane and achieve a yield high enough to generate the residual stream having a by-product concentration sufficient to make the rearrangement reaction practical.
It has now been discovered that a pure 2,2'-bis(4-hydroxyphenyl)propane, having less than about 0.25% and even as low as 0.02% of the o,p'-isomer, can be prepared by (1) crystallizing the crude bisphenol A in the presence of water and an organic solvent, e.g., toluene, (2) mixing the remaining mother liquor (after stripping off water and toluene) with phenol and thereafter contacting with a cation exchange resin in acid form or hydrochloric acid to rearrange the by-products to the desired product, (3) stripping the phenol and recycling to the crystallizer of step 1 or to the primary bisphenol reactor. If a second crystallization is included following step 1, the lowest level of by-product in the final product can be achieved.
SUMMARY OF THE INVENTION
The present invention can produce an exceptionally pure bisphenol A, suitable for making polycarbonate resins, from crude bisphenol A having o,p'-bisphenol A content ranging from 0.2 to 20%. The product yield of p,p'-bisphenol A is consistently above 95%. In the present purification process, the crude bisphenol A having had any unreacted phenol and acetone as well as the water produced in the condensation reaction removed therefrom, is fed to a crystallizer and toluene and a critical amount of water added. The critical amount of water in the crystallizer feed is 2-9% by weight based on the amount of crude bisphenol. This mixture is heated to about 80°-100° C. where a single phase is formed, then slowly cooled to ambient temperature. During the cooling process, it is preferable to hold the temperature between 60°-80° C., the range at which crystals begin to form, for at least 1-30 minutes. The crystal slurry is thereafter further cooled slowly to ambient (20°-35° C.) temperature to complete the crystallization. The remaining mother liquor from this crystallization is distilled to remove water and toluene; phenol is added to the remainder. This mixture contains large amounts of o,p'-bisphenol A and other by-products and is passed through a bed of cation exchange resin (acid form) to convert most of the by-products to the desired p,p'-bisphenol A. The effluent from the cation exchange bed can be recycled to the bisphenol reactor or, after stripping the phenol, can be returned as feed to the crystallizer.
DETAILED DESCRIPTION OF THE INVENTION
In the process of the present invention, the ultimate purity and product yield are dependent on (1) the amount of impurity in the crude bisphenol, (2) the amount of solvent employed with respect to the crude bisphenol, (3) the amount of water in the feed mixture, (4) the temperature and hold time at the beginning of crystal formation, (5) the cooling rate, (6) the solvent selection, and (7) the number of stages of crystallization.
In the present invention using a single batch crystallizer and the optimized conditions, it has been discovered that greater than about 95% of the total impurities can be removed from the crude bisphenol feed, having o,p'-bisphenol content between 0.25 and 15%. It is a well known fact that the more solvent used in crystallization, the purer the crystallized product will be. However, the product recovery yield will suffer because more of the desired p,p'-bisphenol will remain in the mother liquor. It also requires more energy to strip off the solvent from the mother liquor when more solvent is used.
The amount of water in the crystallizer feed is very critical with respect to the final product purity. The presence of water in the feed mixture creates a bis-solvent-water (BSW) phase. It was discovered that the highest purity product and the highest yield of bisphenol could be obtained by crystallizing from this BSW phase. Although the bisphenol crystallizes from either solvent alone, e.g. toluene, or from a bis-water phase as suggested by the art, neither method is as effective as crystallizing from the BSW phase with respect to product purity and yield. In the present invention, a feed with single BSW phase is preferred because it can be handled more easily and more consistently in the process. The relative amount of water, solvent, crude bisphenol and temperature all contribute to the final phase status of the crystallizer feed mixture. There is an optimum water content needed, which depends upon the purity of the starting bis A, to achieve the highest purity in the final product. This water content is that which is necessary to obtain a single phase mixture. From one to four phases can exist in the feed mixture, depending on its composition and temperature.
The initial temperature of between 85° to 100° C. and atmospheric pressure is preferred to create a single BSW phase. It is necessary to increase temperature and operate above atmospheric pressure in order to achieve a single BSW phase if a smaller amount of solvent in the feed mixture is desired. The crystallizer temperature is lowered to a temperature within the range of about 60°-80° C. depending on feed composition, at which point crystallization begins. This is followed by cooling to room temperature (20°-30° C.) to obtain the remaining crystals. To avoid an undesirable high degree of supersaturation, cooling slowly to 60°-80° C. and holding there for a period of time sufficient to begin crystal formation is critical. This controls smooth growth of pure crystal nuclei, which is essential for final product purity. Alternatively, a small amount of purified bisphenol solid can be fed into the BSW phase while at a temperature of 60°-80° C., functioning as crystal nuclei to improve final product purity. Suitable solvents other than toluene and chloroform (principal solvents used as examples in this invention) that can be applied in the present invention are water immiscible solvents such as benzene, xylene, ethylene dichloride, 1,1,1-trichloroethane and methylene chloride. The optimized composition and conditions for solvents other than toluene will differ, but the principle is the same. The final product purity and yield also varies from solvent to solvent. In one method of purifying crude bisphenol A, phenol and acetone are removed from the reactor effluent and the crude bisphenol is fed to a crystallizer with water. The purified bisphenol A crystals are separated from the liquid phase, which is itself separated into a bis-water (BW) and aqueous phase. The BW phase containing high levels of by-product impurities is then treated according to the method of the present invention to produce additional purified bisphenol A by mixing with toluene in another crystallizer. Alternatively the crude bisphenol A from the reactor, having had the phenol and acetone removed is mixed with toluene and water in a crystallizer.
The following description of the process of the present invention is given with reference to the drawing. The crude bisphenol (free from excess phenol, acetone and water) or the BW phase from a previous water crystallization is fed from line 27 into the crystallizer 10, where water and toluene are also introduced through lines 28 and 29, respectively. The crystals of the purified bisphenol (p,p'-isomer) from the crystallizer 10 are fed to a wash vessel 11, where they are rinsed with toluene. The liquid phase containing the impurities (mainly the o,p'-isomer) from the crystallizer, along with the wash liquid from vessel 11 is fed via line 22 to a flash column 12 which removes the toluene and water overhead. The bottoms of the flash column 12 are then mixed with phenol from line 25 and passed via line 23 into an ion exchange bed 13 to convert the o,p'-isomer to the p,p'-bisphenol. The effluent from bed 13 is sent via line 24 to distillation column 14 wherein phenol is removed and recycled via line 25 to the feed to the ion exchange bed. The bottoms of column 14, now richer in p,p'-bisphenol are recycled via line 26 and mixed with the feed in line 27 to the crystallizer.
COMPARATIVE EXAMPLE A (Water Crystallization-Water Wash)
A typical run begins with 200 grams of crude bisphenol (2.6% o,p'-bis and 94-95% p,p'-bis) and 400 grams of water charged into a 1-liter flask. The mixture is heated with agitation until the bisphenol melts and a BW phase is reached. The agitated mixture is cooled slowly to the desired temperature and crystals are allowed to form for 1-2 hours. The crystals are then recovered by filtration and washed with hot water (95° C.). The percent product recovery and o,p'-bisphenol of the purified crystals are presented in Table I. The impurity rich oil coats the outer surface of the relatively purer bisphenol crystals and hot water wash removal is inefficient due to low solubility and selectivity of those impurities in water.
The data from this comparative example indicate that in a solely water purification system the o,p'-bisphenol in the final product can be reduced from 2.6% to 1% with product recovery above 75%. Higher purity can be achieved by additional hot water washing but much lower yields result. Water/bis ratio in Table I is by weight.
TABLE I______________________________________Water Crystallization and Water WashWater/Bis Temp. °C. % Recovery % o,p'-Bis______________________________________ 0/1* 95 80 2.560.6/1 95 75.8 1.692.5/1 90 83.9 1.002/1 87.5 90.8 1.802.5/1 85 93.9 1.93______________________________________ *Fed dry molten bis directly into water.
COMPARATIVE EXAMPLE B (Water Crystallization-Solvent Wash)
The feed for this example was crystals from Example 1. The crystals were washed at room temperature with solvent (chloroform or toluene) for 15-30 minutes with agitation. The solvent was then filtered off and the crystals were dried in an oven. The data for the solvent washing, or leaching, are presented in Table II. The solvent leaching improves significantly the final product purity but the o,p'-bisphenol contents are still too high for polycarbonate grade bis even after six consecutive leachings.
TABLE II______________________________________Water Crystallization and Solvent LeachingInitial % Number of Final %o,p'-Bis Solvent/Bis Washes o,p'-Bis______________________________________1.80 1/1, chloroform 2 0.49 1/1, chloroform 4 0.40 1/1, chloroform 6 0.391.80 1/1, Toluene 2 0.50 1/1, Toluene 4 0.46 1/1, Toluene 6 0.47______________________________________
EXAMPLE 3
Data from Example 1 and 2 indicate that the combination of water crystallization and organic solvent leaching can improve the efficiency of bisphenol purification. A wet bisphenol melt (BW phase) was obtained, as in Example 1, by heating crude bisphenol and water (1:1 by weight) with agitation at 98°-100° C. Ceasing agitation allowed phase separation between the BW phase and water to occur. The BW layer (>95° C.) was slowly added into an agitated flask containing toluene at the desired temperature. After complete addition (˜10 minutes), the mixture was allowed to cool until the initial precipitation of bisphenol crystals began (65°-68° C.). The mixture was maintained at that temperature for one hour. Afterwards, the mixture was cooled to a desired lower temperature and, once attained, allowed to agitate there for an additional one hour. The crystals were separated from the mother liquor by filtration and then washed with one weight (equivalent to the weight of original crude bisphenol) of toluene and dried in a vacuum oven. The results from this example and other similar experiments are presented in Table III. The final product purity was relatively lower if the mixture is not held at the temperature (65°-68° C.) when the crystallization begins. The final temperature of crystallization does not have much affect on the purity of the crystals, but the lower the temperature, the higher the yield. The p,p'/o,p' ratio in the mother liquor is lower when the final crystallization temperature is lower.
TABLE III______________________________________Addition of BW Phase Into Solventand Crystallization from Solvent p,p'/o,p'Solvent: Temp. % o,p'- in Mother %Bis Ratio °C. Bisphenol Liquor Recovery______________________________________2:1,Toluene:Bis 60 0.38 2.99 91.32:1,Toluene:Bis 80 68 40 0.17 1.48 88.51:1,Toluene:Bis 80 66 25 0.19 0.469 92.11:1,Chloroform 60 25 0.25 0.815 83.4______________________________________ The crude bisphenol starting material contained 2.6% o,p'-bisphenol impurity.
EXAMPLE 4
This experiment was carried out similar to Example 3 except the quantity of water and time were reduced. The results are presented in Table IV. The final product purity remains about the same as in Example 3, yet the p,p'/o,p' ratio in the mother liquor is much lower. At this lower ratio the impurities rearrangement reaction is more efficient. As shown in Table IV, addition of the BW phase to toluene at the temperature of precipitation (65°-68° C.) results in almost the same final product purity and eliminates the need for a separate cooling step from 80° C. to 67° C. This example also shows that the quantity of water in the feed, the holding time and the temperature can each be reduced without affecting the final purity and yield of product. An equally pure product is obtained when toluene is recycled from the rinse to the crystallizer. Toluene/bis ratio was 1/1 for each run in Table IV.
TABLE IV______________________________________Reduction of Water Content andCrystallization Time %H.sub.2 O/Bis Temp. Time, % o,p'- p,p'/o,p' in Re-Ratio °C. Min. Bisphenol Mother Liquor covery______________________________________1:1 80 68 30 25 60 0.17 0.37 92.20.25:1 68 15 25 15 0.18 0.31 93.50.20:1 67.5 10 25 10 0.20 0.35 93.3______________________________________
EXAMPLE 5
Example 4 suggested that the process of the invention could be further simplified by pre-mixing crude bisphenol, water and solvent before crystallization. This example illustrates how the feed composition affects the mixture phase state and its effect on final product quality. Crude bisphenol, water and solvent of a desired ratio were charged into a flask with an agitator and heat supply. The temperature of the mixture was brought up to its boiling point and then slowly cooled to 25° C. The resulting crystals are filtered and washed with solvent. When water is not introduced into the crystallization feed, a higher temperature is required to dissolve the crude bisphenol and its product purity is not as high as that crystallized from the BSW phase with optimized water content. With proper feed composition, a single phase of BSW was formed and the crystals produced from it were excellent. The formation of a single phase mixture as feed for the crystallizer in this crystallization process will simplify the plant operation but is not a necessity. Seeding the single phase (BSW) mixture with a small quantity of pure Bis A results in a product of almost equal quality and comparable yield.
TABLE V__________________________________________________________________________Crystallization from Pre-MixedBis-Toluene-Water Temp. (°C.) Boiling Kind and Where BTW Point p,p'/o,p' % o,p'- Number Phase of in Mother Bisphenol ofB:T:W Forms Mixture Liquor in Product Phases__________________________________________________________________________1:2:0 110 110.8 0.86 0.24 1L (T)2:4:1 78-80 85 0.56 0.34 3L (W+T+BTW)4:8:1 78-80 85 0.63 0.20 3L (W+T+BTW)4:8:1 78-80 85 0.58 0.15 1L (BTW)16:32: 0.92 78-80 85 0.40 0.14 2L, 1S (T+BTW+B)__________________________________________________________________________ Note: B Bisphenol (solid), 2.6% o,p'-bisphenol T Toluene (liquid) W Water (liquid) L Liquid phase S Solid phase BTW Bisphenoltoluene-water phase
EXAMPLE 6
The quantity of water in the crystallization feed affecting the number and kinds of phases and the final product quality was previously demonstrated in Example 5. In this example it was determined that optimum quantity of water was needed to achieve the best final product while maintaining a constant bisphenol/toluene ratio. The crude bisphenol from this example has much higher impurity concentrations than either Example 4 or 5 (4.8-5.2%, o,p'-isomer). A mixture of 30 parts bisphenol, 70 parts toluene and the desired amount of water is heated to 87° C. and held there about ten minutes. The resulting mixture, present in several possible phase states, depending on the amount of water in the feed is then allowed to cool slowly to about 35° C. after removal of the heat source. The final crystals are filtered, rinsed with toluene, and then oven-dried. The results from this example are presented in Table VI. The data clearly shows the optimum water content necessary to produce the purest final crystal product. The purest final product is obtained from the feed having one liquid phase or which contains a small quantity of crystals. This prevents oversaturation during the cooling process. The final product purity is further improved when the crystallizer temperature is held constant at 78° C. for a few minutes before further cooling. As the presence of water is reduced to below one part per 100 parts toluene/bisphenol mixture, the amount of solid phase in the mixture is increased but the purity is lower. Crystal seeds with relatively lower purity always result in less pure final crystals. When the quantity of water in the feed mixture is increased to three parts or more, two or three liquid phases are formed. The final product becomes less pure as the water content is increased and multiple liquid phases are formed. This example illustrates the advantage of optimizing water content and the importance of pure crystal seeds.
TABLE VI______________________________________Optimization of Water Content*The feed mixture contained 70 parts toluene and 30parts bisphenol. Final Product Feed Mix BeforeWater, Parts % o,p'-Bisphenol Cooling Phase State______________________________________0 0.33 1L (T), 1S (B)1.0 0.27 1L (T), 1S (B)1.5 0.25 1L (T), 1S (B)2.0 0.21 1L (BTW), 1S (B)2.3 0.25 1L (BTW)2.3*, hold 5 0.21 1L (BTW)min. at 78° C.2.5 0.26 1L (BTW)3.0 0.34 2L (T+BTW)4.5 0.48 3L (T+W+BTW)______________________________________ *The crude bis feed contained 4.8-5.2% o,p'-bisphenol.
EXAMPLE 7
The impurity content of crude bisphenol will vary depending on the source. It can be fairly low when obtained from the preceeding crystallizer product in a 2-stage process or very high when obtained from the residue of a water crystallizer. In this example, the feed mixture composition is 70:30:2 toluene:bisphenol:water. This mixture is heated to about 92° C. where a single liquid phase is formed. The crystallizer is slowly cooled to 77° C. and held for five minutes at that temperature. The crystallizer is finally allowed to cool to 35° C. with continued agitation. The product crystals are filtered and immediately rinsed with fresh toluene before drying in an oven. Using fixed feed composition, the final product purity directly relates to the crude bisphenol purity. About 95% or higher o,p'-bisphenol content has been removed by a single crystallization for feed crude bisphenol having o,p'-bisphenol between 1.2 to 14%. Table VII illustrates that the purity of the final product will vary depending on the original crude bisphenol quality and number of stages of crystallizers.
TABLE VII______________________________________Effect of Impurity ContentsFeed % o,p'- Product % Phase State % o,p'Bisphenol o,p'-Bisphenol Before Cooling Reduction______________________________________1.21 0.030 1L 97.52.50 0.063 1L 97.53.75 0.110 1L 97.15.00 0.205 1L 95.97.50 0.216 1L 97.19.50 0.255 1L 97.311.80 0.395 1L 96.714.0 0.522 1L 96.3______________________________________
Thus, the above experiments indicate that the operable bis:solvent:water ratio is from about 1:0.5:0.01 to about 1:1:0.02 and preferably from about 1:1:0.02 to about 1:2:0.2. | A method of purifying bisphenols by (1) crystallizing the crude bis from a single liquid phase containing water, bis and an organic solvent, (2) stripping the remaining mother liquor (containing the impurities) of solvent and water, and (3) mixing it with phenol, (4) contacting the mixture of phenol and mother liquor with a cation exchange resin to convert the impurity to the desired product, (5) stripping the phenol and (6) recycling the remainder to the initial crystallizing step. | 2 |
This patent application is a Divisional patent application of U.S. patent application Ser. No. 09/103,191, entitled “Hair Sculpted Jewelry Piece and its Method of Manufacture,” to Don S. Cannon, filed Jun. 23, 1998, which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to jewelry and ornaments formed by means of casting. More particularly, the present invention relates to a novel method of creating an ornament or piece of jewelry for which the casting mold is formed by an impression from a sample of hair.
2. State of the Art
Investment casting, sometimes called “lost wax” casting, is a well known method of producing intricate cast shapes, and has been widely used by artists, jewelers, dentists, and so forth for many years. Investment castings are generally created by carving, shaping or in some way forming from a wax, resin, or other suitable material a full size three dimensional pattern of the object to be cast. This pattern is enveloped in a mold material which intricately conforms to the shape of the pattern, and is then heated to harden the mold material and to melt or vaporize the wax or resin of the pattern so as to leave behind, within the hardened mold material, a mold having an empty space of the exact shape and size of the pattern. Molten metal or some other desired material is then forced into the mold space to produce the finished part.
One of the great benefits of investment casting is that the mold comprises a single piece that fully encases the pattern. This allows the reproduction of very intricate detail in the casting. Also, because the pattern vaporizes, there is no need to remove it, and thus no need for a two part mold. This avoids the creation of a line or ridge in the casting that frequently forms at the interface of the halves of two part molds.
The inventor has discovered that investment casting may also be performed using objects other than a wax replica as a pattern. Because the investment casting process involves heating the mold material to melt or vaporize the pattern, some objects or substances comprised of organic materials may be cast using the actual object as the pattern. During the heating process the organic material bums or vaporizes away, leaving an empty mold space just as when using a wax pattern. For example, the inventor has successfully made highly detailed castings using actual spiders as the pattern.
The investment casting process is particularly useful for casting jewelry such as pins, pendants, rings, earrings, medallions, etc. Jewelry may function to embody beauty in the form of art or provide a setting for precious stones, or be used as an ornament for picture frames, urns, and other items. Also, jewelry is often a means of symbolizing close relationships or serving as a memento or reminder of a special moment or person.
People frequently desire to have some tangible reminder of a pet or a loved one, particularly when that pet or loved one is deceased. While means exist for preserving all or part of a body, such means are not generally permanent, and keeping such an item as a memento is not generally considered socially acceptable, tasteful, or desirable. Except occasionally in the field of taxidermy, the same is true for items that do not easily decay such as teeth or hair. It would be desirable to have a method of tastefully preserving some tangible reminder of the physical person of a loved one or pet in a form that is considered socially acceptable, and also conveys some indication of the value one places on the memory of that person or pet.
Traditionally, pieces of jewelry such as a locket, pocket watch, pendant, medallion, etc. have been used as tangible, durable mementos of a loved one, particularly when engraved with a meaningful message. Frequently a photograph, and in some cases, a lock of a person's hair is attached to or enclosed within such pieces of jewelry as a reminder. The piece of jewelry thus has sentimental value as a reminder of the person, and may have significant monetary value as well. However, the photo or lock of hair will both eventually deteriorate, possibly leaving a piece of jewelry that has lost a large portion of its emotional value. It would be desirable to have a method of creating jewelry or an ornament of some kind that incorporates a physical reminder of a person such as hair in a durable permanent form that may become part of a piece of valuable jewelry, or may be attached to a picture frame, cremation urn, or other memorial.
OBJECTS AND SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an item of jewelry and a method of producing the same, wherein the jewelry comprises the form of hair, such as human hair, in an aesthetically pleasing geometric configuration, said item having been cast in a mold formed from a sample of actual hair.
It is another object of this invention to produce an item of jewelry and a method for its production in which the jewelry is made by investment casting wherein the mold pattern comprises actual hair in an aesthetically pleasing geometric configuration.
It is another object of this invention to produce an item of jewelry comprising the form of human hair which includes an engraved identification of the person from whom the hair sample was obtained.
The above and other objects are realized in an item of jewelry comprising the form of hair, such as human hair, in an aesthetically pleasing geometric configuration, said item having been cast in a mold formed by a sample of actual hair. The name or other identification of the person from whom the hair came may be engraved or otherwise permanently affixed to the piece of jewelry.
Some of the above objects are also realized in a method of creating a piece of jewelry using hair, such as human hair, comprising the steps of obtaining a sample of hair, arranging the sample in an aesthetically pleasing geometric configuration, and forming an impression of the hair sample in a permanent representation as part of jewelry by an investment casting process wherein the sample of hair is consumed in the casting process.
Other objects and features of the present invention will be apparent to those skilled in the art, based on the following description, taken in combination with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts a sample of hair gathered together ready to be used for the present invention.
FIG. 2 shows the sample of hair gathered in a bundle with opposite ends secured.
FIG. 3 depicts the hair bundle with its ends clamped and twisted into a cord.
FIG. 4 shows the cord grabbed by a hook which will pull and twist it into a braid.
FIG. 5 shows the braid ready to be cut and mounted.
FIG. 6 shows an exploded view of the braid cut to size and being mounted on an extruded wax channel.
FIG. 7 shows the braid and extruded channel mounted onto a jewelry pattern formed of wax material.
FIG. 8 shows the wax jewelry pattern encased in a casting ring.
FIG. 9 shows the finished piece of jewelry with the braided hair pattern.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings:
FIG. 1 depicts a sample of hair strands 10 gathered together ready to be used for the present invention. The hair strands 10 should preferably be of approximately the same length, but in any case should be at least as long as the intended bundle. In the preferred embodiment, the bundle should comprise from approximately 70 to 120 strands of hair, and the strands should be approximately 1.75 inches long or longer. Fewer strands may be used, but will tend to make unsatisfactory braids. More strands will tend to be difficult to twist or braid. In one embodiment, hair shorter than 1.75 inches long is used.
If it is not desired to arrange the hair in a twisted or braided configuration, the hair at this point may be arranged into any desired geometric configuration, and fixed in that configuration by any means that will not hide the texture of the hair, and will allow the hair to impress the mold material without allowing mold material to adversely seep between hair strands. Products generally known as “superglue” or similar liquid adhesives that are relatively non-viscous may serve to fix the hair in this manner. The hair may then be attached to a wax jewelry pattern as depicted in FIG. 7, and the process followed from that point, or the hair form may be attached to a wax sprue and cast individually.
FIG. 2 shows the sample of hair 10 gathered in a bundle with the hair strands roughly parallel and opposite ends secured tightly together an appropriate distance d 0 apart, leaving the ends of the hair 14 free. The bundle is preferably comprised of a sufficient number of hair strands to form a bundle of approximately {fraction (1/16)} in. diameter when the hair is tightly bundled, and the preferred length d 0 of the hair bundle is from approximately 1.25 to 2.0 inches. Any satisfactory method of securing the hair bundle will do. In the preferred embodiment the bundle is held together by leather washers 12 a and 12 b which comprise central openings of a size adequate to tightly hold the size of bundle chosen.
As shown in FIG. 3 the leather washers 12 are securely grasped by clamping means 16 a and 16 b . These clamping means may comprise any suitable clamping devices, such as standard alligator clips as shown in FIG. 3 . The clamping means are resistively secured opposite each other by stiffly compliant means 17 a and 17 b so as to apply a tensile force to the hair bundle. Said stiffly compliant means may comprise springs, and should create a force adequate to hold the hair bundle tightly together, but not so strong as to break the hair strands.
Clip 16 a is rotationally secured in place, while the opposing clip 16 b is rotated about the axis 18 of the hair bundle, forming a cord 19 comprised of approximately helically twisted hair strands. As will be readily appreciated, either end 16 a or 16 b of the bundle may be secured, and the opposing end rotated. Similarly, the direction in which the bundle is rotated about axis 18 does not matter. It will also be readily appreciated that the twisting procedure causes the hair bundle to shorten, drawing the clamping means 16 toward each other against the force of the stiffly compliant means 17 , making the length d 1 of the cord 19 less than the original length d 0 of the hair bundle 10 . Care must be taken to twist the cord 19 an appropriate amount. If it is twisted too tightly, the cord will tend to kink. However, to produce a satisfactory and serviceable casting the cord must be twisted tightly enough so that mold material cannot adversely seep between the strands of the cord later in the process.
The cord 19 may contain some broken, stray hair fibers that diverge from its body. This will not prevent a serviceable casting, and from an aesthetic standpoint may be desirable to help show the texture of the hair and to make it more obvious that the finished casting was created from real hair.
FIG. 4 shows the cord 19 ready to be braided. If braiding is not desired, the cord may be fixed in its twisted configuration, cut to length, and used to create a mold by any means that, as noted above, will fix it in the desired geometric configuration, that will not hide the texture of the hair, and that will allow the hair to impress the mold material without allowing the mold material to seep between hair strands. As noted, “superglue” or similar strong, relatively non-viscous adhesive will serve to fix the hair in this manner. The cord may then be cut along lines 30 to some desired length, fixed to a wax channel, sprue, or jewelry pattern as depicted in FIGS. 6 and 7, and the process followed from that point.
To begin braiding, both clamping means 16 are rotationally secured, and the cord 19 is hooked by a hook 20 at a point approximately midway between the clamping means. The hook 20 is pulled by a pulling means 26 , such as a rod or spring, in a direction 22 along an axis 23 that is perpendicular to the axis 18 of the cord 19 , and is simultaneously rotated in the direction of arrow 24 about the axis 23 of the pulling means. This procedure will draw the clamping means 16 toward each other against the stiffly compliant means 17 in the direction of arrows 25 , and will cause the cord 19 to twist about itself, creating a two-cord braid 28 . As with the original twisting operation, care must be taken to not to braid too tightly. If the cord is braided too tightly, it will tend to kink. However, it must be braided tightly enough to prevent mold material from seeping between the cords.
As noted above, the twisted hair bundle need not be braided to be used in the method of this invention. It will also be appreciated that cords may be braided in other ways in addition to the two-cord braid depicted in FIGS. 4 and 5. Any method of braiding, such as braiding three cords or four cords or more, and any braiding apparatus now know or later conceived may be employed to create the desired hair configuration in accordance with this invention.
FIG. 5 shows the braid 28 ready to be cut and mounted. At the end of the braiding operation, the braid 28 will have a length d 3 that is less than half of the prior length d 1 of the cord, and the clamping means 16 will be separated by a distance d 2 that is significantly smaller than distance d 1 due to the braiding.
The braid is fixed in its twisted configuration by some adhesive such as “superglue” that, as noted above, will fix the hair in its desired geometric configuration, will not hide the texture of the hair, and will allow the braid to impress the mold material without allowing the mold material to seep between braid cords. The braid 28 is then cut along lines 30 creating a segment of some desired length. As with the individual cords, as noted above, the braid may contain some broken, stray hair fibers that diverge from the body of the braid. This will not prevent a serviceable casting, and from an aesthetic standpoint may be desirable to help show the texture of the hair and to make it more obvious that the finished casting was created from real hair.
FIG. 6 shows an exploded view of the cut braid segment 28 in the process of being mounted on a base 38 . The base 38 comprises a channel of a length L which approximately matches the length of the braid segment 28 , and has a radius R that is complementary to the curvature of the braid 28 in cross-section. This channel is made of wax, resin, or other material suitable for making a pattern for a lost wax casting, and is typically formed by an extrusion process. The ends 31 of the braid 28 or other hair piece is normally affixed to the base 38 by small daubs of highly adhesive wax 32 , frequently referred to as “sticky wax,” applied at each end 31 of the segment, or by other suitable adhesive means. It will be appreciated that the base 38 need not take the form of a channel, and may be formed in any configuration required by the hair bundle and the intended jewelry piece, depending on the size and shape of the bundle or hair arrangement, whether it is braided or not, and the number of strands comprising the braid. It will also be appreciated that the hair piece may be attached directly to a wax jewelry form, and need not be attached to a channel or base. However, the additional base piece is often useful for handling purposes.
FIG. 7 shows front and side views of the braid and base mounted onto a jewelry pattern formed of wax material. The braid 28 and mounting channel 38 are incorporated into a pattern 34 that, like the base 38 , is comprised of the same type of material as the base 38 , being wax or other material suitable for a pattern for lost wax casting. The pattern provides the ornamental shape desired to be incorporated into the jewelry in addition to the shape and style of the hair braid, and as shown here is in the form of a ring. It will be appreciated that the jewelry pattern may form other types of jewelry or ornaments such as pins, broaches, pendents, medallions, etc., and may take an infinite variety of ornamental shapes and styles as desired. Furthermore, it will be appreciated that in accordance with the present invention the hair sample and its mounting base may be cast alone, without mounting onto a jewelry pattern of any kind. This procedure is useful when it is desired to create a jewelry piece or ornament in which the hair sculptured pattern is formed of a different material than the jewelry piece or other item on which it is mounted. For example, one could create a silver or platinum hair sculptured piece mounted on a gold ring, pendant, picture frame, or crematory urn. Alternatively, one could in accordance with this invention create a gold hair sculptured piece or medallion mounted on a silver crematory urn or picture frame. It will be appreciated that these are just a few of the many possible variations and embodiments of the present invention.
The braid 28 and base channel 38 are affixed to the pattern 34 by means of small daubs of highly adhesive wax 32 applied at each end 31 of the segment, or by other suitable adhesive means. The jewelry pattern also comprises a sprue 36 that is integrally connected with the pattern 34 and is made of the same pattern material. The sprue 36 is of a cross-section and length that will enable it to communicate with the exterior surface of the mold material when the pattern 34 is fully encased, and that when melted will leave a passageway in the mold material that communicates between the mold space and the exterior of the casting ring, and is of a size suitable for passage of the liquid casting material.
FIG. 8 shows the wax jewelry pattern 34 encased in a casting ring, denoted generally at 40 , which is designed to be placed in a saddle at the end of the arm of a typical centrifugal casting machine such as is well known in the art. The casting ring 40 typically comprises a cylinder 44 that is open on both ends, and a cone shaped base 41 . When the wax jewelry pattern 34 is complete, with the hair sample in place, it is mounted on the base 41 with the sprue 36 downward, the bottom end 46 of the sprue being firmly attached to the center of the base 41 , at the apex of the cone shape. The cylinder 44 is then placed over and around the pattern 34 and connected to the base 41 such that the pattern 34 is entirely within the cylinder, but does not touch its sides. This ensures that all portions of the pattern, except the very end of the sprue 46 which is attached to the base 41 , will be completely enveloped when the liquid mold material is poured into the top of the cylinder, denoted at 42 . Then a suitable liquid mold material is poured into the cylinder. Suitable mold materials include but are not limited to commercially available high heat investment products such as “Beauty-Cast” gypsum investment for low-fusing alloys, manufactured by Whip Mix Corp., and “Cera-Fina” fine grain carbon-free investment, also manufactured by Whip Mix Corp.
Care must be taken to ensure that the mold material 42 envelopes all surfaces and details of the pattern 34 , and that all bubbles and air pockets are removed from the liquid casting ring. This may be accomplished through vibration of the casting ring during the process of pouring the liquid mold material. After the pattern is thus encased in the mold material, the end of the sprue 46 , having been attached to the center of the cone shaped base 41 , will form the apex of a funnel once the investment material has solidified and the base 41 is removed.
To prepare for casting, after the mold material is in place the casting ring 40 is placed in an oven and heated to a suitable temperature. The temperature and duration of heating required depend on the particular mold material and the temperature necessary to vaporize the wax pattern and hair. Additionally, the mold must be heated to at least the temperature of the molten material to be cast. This temperature is maintained during the casting process so that the molten material will not cool and solidify prematurely upon its introduction into the mold. Typically, casting rings of this sort are heated in the range of from 800° F. to 1400° F. depending on the type of casting material to be used. The heating process causes the liquid mold material 42 to solidify and cure by driving all moisture out of the liquid mold material, and simultaneously causes the wax pattern, sprue, and hair sample to vaporize. This process leaves a hard but somewhat porous casting ring 40 with an empty internal mold space in the exact shape of the pattern 34 and connected hair sample 28 , and leaves a passageway in place of the sprue 36 which communicates between the internal mold space and the center of the funnel formed by the base 41 . What was the end of the sprue 46 is now an opening in the center of the funnel. Importantly, the porosity of the hardened casting ring allows air to be driven out of the mold when the molten metal is introduced.
To cast the piece of jewelry, the casting ring is placed in a centrifugal caster, and a suitable liquid casting material is forced by centrifugal force into the opening 46 of the passageway formed by the sprue 36 , and passes into the mold space left by the pattern 34 . Suitable casting materials include all types of precious metals and alloys typically used for jewelry, in molten form, including but not limited to gold, silver, copper, platinum, and so forth. It will be apparent that castings may also be made following the method of this invention from other materials including non-metals.
Once the casting has solidified, the casting ring is stripped away, and the casting is thoroughly cleaned and polished as is typical of cast jewelry. The sprue 36 , now comprised of the solidified casting material, unwanted burrs, including globs formed where the daubs of sticky wax were placed, and other defects may be removed by grinding, polishing, and other suitable processes known in the art. FIG. 9 shows the finished casting 48 with the braided hair pattern 50 . The jewelry piece is now ready to be worn and displayed with the decorative pattern from actual hair.
In one embodiment of the present invention, the item of jewelry formed is selected from the group consisting of a ring, earring, pin, pendant, tie tack, tie clip, tie bar, broach, bracelet, watch or wristwatch, hair pin, barrette, necklace, button, and cuff links.
It is to be understood that the above-described methods are only illustrative of the application of the principles of the present invention. Numerous modifications and alternative methods may be devised by those skilled in the art without departing from the spirit and scope of the present invention, and the appended claims are intended to cover such modifications. | An item of jewelry such as a ring, earring, pin, pendant, tie tack, tie clip, tie bar, broach, bracelet, watch or wristwatch, hair pin, barrette, necklace, button, cuff links, or a medallion, and a method for forming the same wherein the item comprises the form of hair in an aesthetically pleasing geometric configuration such as a braid, said item having been cast in a mold formed at least in part by a sample of hair such as human or pet hair. Such an item which is made by investment casting, wherein at least a portion of the investment mold pattern comprises the hair sample. Such an item with a permanent designation of the person who was the source of the hair. Such an item used to adorn a memorial such as a crematory urn, picture frame, or memorial plaque. | 1 |
BACKGROUND OF THE INVENTION
Arts and Practices
Boric acid derivatives are known in the art. Boric acid esters are a class of compounds which conform to the following structure;
(RO).sub.3 --B
There are a variety of methods of preparation of borate esters. The most common preparative method for boric acid esters is the reaction of boric acid with an alcohol. Low molecular weight alcohols are used in this process. The boric acid ester produced in the greatest quantity is methyl borate, used in the synthesis of sodium borohydride. The utilization relates to the hydrolytic instability of the ester and its reactivity to prepare the borohydride.
The most important references to other methods of preparation of borate esters are as follows;
U.S. Pat. No. 3,454,617 issued in 1969 to Fischer et al discloses a process for the preparation of borate esters of long chain aliphatic alcohols by oxidation of paraffins in the presence of boric acid. This method is not applicable to the compounds of the present invention since the critical guerbet alcohol portion of the molecule cannot be prepared by oxidation of paraffin. Additionally, there is no possibility to include alkylene oxide into the molecule using the Fischer technology.
U.S. Pat. No. 3,660,459 issued in 1972 to Hughes discloses that amino alcohols can be reacted with boric acid to make amino borates which can subsequently converted into quaternary ammonium compounds. These materials are useful as fabric softeners. These compounds are different from the compounds of the present invention in that they utilize amino alcohols, and do not recognize the importance of the guerbet functionality. Additionally, there is no possibility to include alkylene oxide into the molecule using this technology.
U.S. Pat. No. 3,723,495 issued in 1973 to Holtz discloses that unsaturated alcohols can be prepared by the reaction of triolefins with boron compounds followed by hydrolysis. These compounds are different from the compounds of the present invention in that they are alcohols. Not borate esters based upon guerbet alcohols. Additionally, there is no possibility to include alkylene oxide into the molecule using this technology. Borate esters of the prior art hydrolyze easily giving back the starting alcohol. This hydrolytic instability has significantly limited the utilization of these materials in many applications.
Guerbet alcohols, one raw material used in the preparation of the compounds of the present invention, are known to those skilled in the art. Many early patents dealt with the choice of catalyst for the preparation of the beta branched alcohol. Later patents dealt with compounds, compositions and processes which utilize the liquid nature of guerbet derivatives.
Several patents have issued which describe derivatives of guerbet alcohols. None of the patents describe in any way borate esters. All patents use the guerbet alcohol to obtain high molecular weight and liquidity in the products. Typical examples of such patents are;
U.S. Pat. No. 4,425,458 issued in 1984 to Lindner et al teaches that certain guerbet alcohol diesters are useful as plastic lubricants.
U.S. Pat. No. 4,731,190 issued in 1988 and U.S. Pat. No. 4,830,769 both issued to O'Lenick et al, and incorporated herein by reference, teaches that certain guerbet alcohol alkoxylates are useful as metal working lubricants.
U.S. Pat. No. 4,868,236 issued in 1989 to O'Lenick teaches that certain guerbet alcohol citrate esters are useful as plastic lubricants.
U.S. Pat. No. 4,800,077 issued in 1989 to O'Lenick et al, which is incorporated herein by reference, teaches that certain guerbet alcohol based quaternary compounds are useful liquid cosmetic and personal care compounds.
Oil soluble borate esters have been added to aircraft fuel because as they hydrolyze, boric acid results which inhibits the growth of microorganisms.
The compounds of the present invention, unlike other borate esters, are surprisingly stable to hydrolysis, lubricious, non irritating liquids which form films when applied to substrates like skin, hair and textile fibers.
THE INVENTION
The present invention deals with the composition, and application of novel highly branched borate esters, which are surprisingly hydrolytically stable and are oil phases for use in personal care, textile and related applications. The properties of these novel compounds which makes them well suited for these applications is the fact that they are substantive to fibers, hair and skin, are very mild to the skin and eyes.
A surprising feature of the compounds of the present invention is that a unique non greasy feel is obtained when the products of the present invention are applied to the skin. This makes the materials of the present invention very useful in personal care products. It is the use of beta branched alcohols like guerbet alcohols or aldol alcohols and their alkoxylates with their unique branching that results in the unique properties of these materials.
OBJECT OF THE INVENTION
It is the object of this invention to produce a high molecular weight borate ester that is highly lubricious, nonirritating, and stable to hydrolysis. The nature of these borate esters surprisingly relates to the fact that these borate esters are prepared from guerbet alcohols and their alkoxylates. The specific branching pattern, in addition to producing liquid derivatives also results in the desired stability to hydrolysis of these compounds. Additionally, the use of high molecular weight branched hydrophobic alcohols in the preparation of the compounds of the present invention results in products which are less irritating.
It is also an object of the present invention to provide a process of treating fiber which comprises contacting the fiber with an effective lubricating amount of the compounds of the invention.
The references cited herein are incorporated by reference to the extent applicable. Ratios and percentages are by weight and temperatures are Celsius unless otherwise stated.
DETAILED DESCRIPTION OF THE INVENTION
The compounds of the present invention are prepared by the reaction of the guerbet alcohol, or aldol alcohol or their alkoxylates with boric acid more specifically anhydrous boric acid.
Anhydrous boric acid, B 2 O 3 , is more properly called boric anhydrous. Other names include boron oxide, boron trioxide, or boron sesquioxide. It is a brittle, hygroscopic crystal.
Both types of alcohol from which the borate can be produced are highly regiospecifically beta branched. The difference is that one is dialkyl at the beta branch, the other is alkyl, alkylether branched. ##STR1## It will be understood by those skilled in the art that the above definition of R' and R" will also include several other positional isomers.
Oxo alcohols, which have some methyl or other lower alkyl branch in the beta position are not suitable raw materials for the preparation of the compounds of the present invention. Oxo alcohols typically have between 20 and 30% methyl branching in the beta position. This is a consequence of the process used to make them. They lack the stability to hydrolysis exhibited by the higher alkyl and alkyl ether derivatives of the present invention. Additionally, they lack the lubricious properties and low irritation properties of the compounds of the present invention.
Aldol Alcohols used as raw materials in the preparation of compounds of the present invention are a new series of branched ether alcohols and their alkoxylates recently developed by Nova Molecular Technologies, Lake Geneva, Wis.
The alcohols, marketed under the trade name "Aldol Alcohol" and conform to the following structure; ##STR2## R 3 is lower alkyl; EO is --(CH 2 CH 2 --O)--
PO is --(CH 2 CH(CH 3 )--O)--
x, y and z are independently integers from 0 to 20;
m is 1 or 2;
n is 1 or 2.
Guerbet Alcohols, the other type of beta branched alcohols useful as raw materials, have been known since the 1890's when Marcel Guerbet first synthesized these materials (M. Guerbet, C.R. Acad. Sci. Paris, 128, 511; 1002 (1899)). These materials are high in molecular weight and are liquid to very low temperatures. The guerbet reaction gives very specific branching in the alcohol as shown; ##STR3##
As can be seen by the above reaction the molecules have substitution on the second carbon from the hydroxyl group. This branching has been found to be critical to the preparation of a product having the desired properties. If the branching were on the same carbon as the hydroxyl group, the hydroxyl group would be a secondary one and would be very hindered and has low reactivity. As one moves the branch position away from the beta carbon, the ability to liquefy under pressure, and condition to hair and fiber decreases.
Guerbet alcohols that are the reaction product of one specific raw material alcohol will result in a so called "homo-guerbet". In this case the product is symmetrical. If the starting alcohols used in the guerbet reaction are of differing molecular weights a so called "hetero-guerbet" results. This type of guerbet has a mixed distribution of all possible combinations of alcohols. For this reason R and R' in the generic formula may be the same or different. ##STR4## The beta branched alcohol or alkoxylate is reacted with the boric acid under catalytic conditions to give the borate ester and water. The water is removed by distillation. Vacuum is used to drive the reaction to completion. ##STR5## The reaction can be run without a catalyst. Catalysts are generally used at concentrations of between 0.05% to 0.50% with a preferred range of 0.1% to 0.3%. Catalysts which are effective include but are not limited to; sulfuric acid, p-toluene sulfonic acid, methane sulfonic acid, tin metal, zinc metal, titanium metal, organo titanates, organo tin compounds, organo zinc compounds, zinc oxide, magnesium oxide, calcium oxide, etc. Preferred is stannous oxylate. The reaction is conducted at between 140° and 240° C. under an inert nitrogen blanket. Preferred temperature range is between 180° and 210° C. Water is removed from the reaction which is done using a nitrogen sparge or vacuum of up to 10 mm.
Preferred Embodiments
In a preferred embodiment the sum of the carbon atoms in R 2 and R3 ranges from 14 to 22. Within this range the maximum lubrication under pressure and the maximum lubricity is obtained. Compounds having lower values are not lubricious enough, and those with higher values do not exhibit the optimum lubrication properties. Most preferred values for the sum of the carbon atoms in R 2 and R3 are 14 to 18.
In a preferred embodiment x, y and z are all zero. Another preferred embodiment x, y and z are each between 1 and 10.
The fibers which have been successfully treated with the compounds of the present invention are hair and textile fiber. The preferred textile fibers are cotton and polyester.
The preferred concentration of compound to obtain the desired lubricating effect is between 0.01 and 25%. More commonly the concentration ranges from 0.1 to 5%.
EXAMPLES
EXAMPLES OF GUERBET ALCOHOL
The preparation of guerbet alcohols is a process known to those skilled in the art. The reaction is conducted commercially by several companies including Exxon Chemical, Henkel Corporation, Condie Cheime, and Alkaril Chemicals. Guerbet alcohols are alkoxylated using processes known to those skilled in the art and are available from Nova Molecular Technologies. Guerbet Alcohols conform to the following structure ##STR6## R 2 is alkyl having from 4 to 24 carbon atoms; R 3 is alkyl having from 4 to 24 carbon atoms;
EO is --(CH 2 CH 2 --O--)--;
PO is --(CH 2 CH(CH 3 )--O--)--;
x,y, and z are independently integers each ranging from 0 to 20.
______________________________________Example R.sup.3 R.sup.2 x y z______________________________________1 C.sub.8 H.sub.17 C.sub.10 H.sub.21 0 0 02 C.sub.8 H.sub.17 C.sub.10 H.sub.21 5 5 53 C.sub.8 H.sub.17 C.sub.10 H.sub.21 20 10 204 C.sub.10 H.sub.21 C.sub.12 H.sub.23 1 10 55 C.sub.10 H.sub.21 C.sub.12 H.sub.23 0 0 06 C.sub.10 H.sub.21 C.sub.12 H.sub.23 5 5 57 C.sub.10 H.sub.21 C.sub.12 H.sub.23 10 10 108 C.sub.7 H.sub.15 C.sub.5 H.sub.11 3 10 09 C.sub.7 H.sub.15 C.sub.5 H.sub.11 0 0 010 C.sub.18 H.sub.37 C.sub.16 H.sub.33 10 10 1011 C.sub.18 H.sub.37 C.sub.16 H.sub.33 5 5 412 C.sub.18 H.sub.37 C.sub.16 H.sub.33 0 5 1213 C.sub.10 H.sub.21 C.sub.10 H.sub.21 1 0 614 C.sub.10 H.sub. 21 C.sub.10 H.sub.21 20 3 1415 C.sub.8 H.sub.17 C.sub.8 H.sub.17 5 1 016 C.sub.8 H.sub.17 C.sub.8 H.sub.17 0 0 0______________________________________
Examples of Aldol Alcohols
The following aldol alcohols are available from Nova Molecular Technologies, Lake Geneva, Wis.;
______________________________________Exam-ple Name n m x y z______________________________________17 ALDOL ALCOHOL 21 1 1 0 0 018 ALDOL ALCOHOL 27 2 2 0 0 019 ALDOL ALCOHOL 1 1 3 0 0 21-E320 ALDOL ALCOHOL 1 1 5 0 0 21-E521 ALDOL ALCOHOL 1 1 15 0 0 21-E1522 ALDOL ALCOHOL 1 1 20 0 0 21-E2023 ALDOL ALCOHOL 2 2 0 20 20 27-P20-E2024 ALDOL ALCOHOL 2 2 10 10 0 27-E10-P1025 ALDOL ALCOHOL 2 2 5 4 0 27-E5-P426 ALDOL ALCOHOL 2 2 20 0 0 27-E20______________________________________
Boric Acid Reactions
EXAMPLES 27-52
To the specified amount of the specified guerbet alcohol, aldol alcohol or guerbet alcohol alkoxylate, aldol alcohol alkoxylate is added the specified number of grams boric acid and 2.0 grams of stannous oxylate (Fascat 2001). The temperature is then increased to 160°-200° C., under nitrogen sparge. By-product water begins to distill off. Vacuum is applied to keep the water distilling. When 97% of the theoretical water is removed the reaction is cooled. The desired product is obtained without and additional purification.
______________________________________Guerbet Reactant Boric Acid CatalystExample Example Grams Grams Type Grams______________________________________27 Examp. 1 244.0 116.4 None28 Examp. 2 979.0 116.4 None29 Examp. 3 3428.0 116.4 None30 Examp. 4 1206.0 116.4 None31 Examp. 5 308.0 116.4 None32 Examp. 6 892.0 116.4 None33 Examp. 7 1778.0 116.4 None34 Examp. 8 904.0 116.4 None35 Examp. 9 182.0 116.4 None36 Examp. 10 1948.0 116.4 B 12.037 Examp. 11 1169.0 116.4 B 10.038 Examp. 12 2074.0 116.4 B 12.039 Examp. 13 590.0 116.4 B 2.040 Examp. 14 1955.0 116.4 B 1.041 Examp. 15 485.0 116.4 B 0.542 Examp. 16 206.0 116.4 C 12.043 Examp. 17 294.0 116.4 A 12.044 Examp. 18 378.0 116.4 A 2.045 Examp. 19 426.0 116.4 A 12.046 Examp. 20 514.0 116.4 A 12.047 Examp. 21 954.0 116.4 A 2.048 Examp. 22 1174.0 116.4 A 0.949 Examp. 23 2438.0 116.4 A 12.050 Examp. 24 1408.0 116.4 A 8.051 Examp. 25 836.0 116.4 None52 Examp. 26 1256.0 116.4 B 12.0______________________________________ Catalysts A is stannous oxylate (Fascat from ATO Chem) B is an organo titanate (Tyzor from DuPonte) C is para toluene sulfonic acid
HYDROLYTIC STABILITY
Compounds of The Present Invention
______________________________________ % Hydrolysis 1 gram in 60 CExample Number water for 24 hrs.______________________________________27 1.231 2.035 0.842 0.943 1.144 1.0______________________________________Comparative Compounds % Hydrolysis 1 gram in 60 CCompound Name water for 24 hrs.______________________________________Tridecyl borate 95.3(Derived from decyl alcohol)Trilauryl borate 97.6(Derived from lauryl alcohol)Trimethyl borate 100.0(Derived from methanol)______________________________________
As can be easily seen from the above data the compounds of the present invention have outstanding hydrolytic stability. | The present invention deals with the composition, and application of novel highly branched borate esters, which function as unique oil phases for use in personal care, textile and related applications. The properties of these novel compounds which makes them well suited for these applications is the fact that they are substantive to fibers, hair and skin, are very mild to the skin and eyes. These materials are surprisingly stable to hydrolysis. | 3 |
CROSS REFERENCE TO RELATED APPLICATIONS
The present application claims the benefit of the provisional patent application filed on Aug. 5, 2005, and assigned application No. 60/705,824. The present application also claims priority of German application No. 10 2005 037 018.7 filed on Aug. 5, 2005. Both of the applications are incorporated by reference herein in their entirety.
FIELD OF THE INVENTION
The invention relates to a gantry system for a particle therapy facility, having a beam guidance gantry which has elements for beam guidance.
BACKGROUND OF THE INVENTION
In particle therapy, gantry systems are used to irradiate patients from different directions with particles, that is to say protons, carbon ions or oxygen ions, for example. For this purpose the gantry comprises a plurality of deflection magnets which rotate about the axis of rotation of the gantry system. Beam monitoring elements are usually arranged at a beam exit. These elements supply, for example, information concerning the site and intensity of the particle beam and are used for the output of controlled variables which notify a control system of the site and number of particles administered and of the amount of energy used. This is necessary especially in the case of radiation therapy using a scan system, since here the proton beam scans over the tissue to be irradiated in the form of what is called a pencil beam. Examples of gantry systems are known, for example, from EP 1 396 278 A2, EP 1 479 411 B1 and EP 1 402 923 A1.
In known gantry arrangements the particle beam is directed onto a stationary treatment target known as the isocenter. The irradiation angle can be freely adjusted such that a patient awaiting treatment can be irradiated from different directions in the same treatment position. Owing to the high particle energies of some 100 MeV, correspondingly large deflection magnets are required for beam guidance. These magnets are arranged on a frame and can rotate on circular paths with relatively large radii of, for example, some meters about an axis of rotation which extends through the isocenter. The problem thus arises, in particular, that the gantry system, which has been dimensioned with a view to adequate rigidity, nevertheless, depending on the angle of rotation, undergoes different displacements or distortions or deformations such that, for example, the positions of the deflection and beam-forming magnets vary. This has a disadvantageous effect on precision during guidance of the particle beam and thus on accuracy of aim and reproducibility.
The problem of the considerable structural dead weight has a heightened effect in the case of gantry systems for heavy ions (carbon ions), since here the magnets and the beam guidance elements arranged between the magnets are substantially heavier.
SUMMARY OF THE INVENTION
An object of the invention is to provide a gantry system which enables accurate radiation therapy to be administered irrespective of the displacements or distortions or deformations of the gantry.
This object is achieved as claimed in the invention by virtue of a gantry system for a particle therapy facility as claimed in the independent claim, which system comprises a beam guidance gantry which has elements for beam guidance, and a measurement gantry which has a device for beam monitoring. The device thus measures at least one beam parameter of the administered beam, the beam parameter being provided for control of the particle therapy facility.
The device for the output of the parameter is preferably provided on a control system of the particle therapy facility. As part of the beam monitoring apparatus, the device can thereby provide feedback for the administration of radiation therapy.
For an irradiation procedure the measurement gantry is preferably first rotated into an angular position intended to form the basis for the radiation therapy. In this position, a measuring unit of the device for measuring particles is then exposed to radiation after the beam guidance gantry has been correspondingly rotated. This enables beam parameters, in particular the site and/or the energy and/or the number of administered particles of the beam to be measured.
One advantage of an embodiment of the invention is that the effects of displacements or distortions or deformations caused by the weight load of the beam guidance elements such as deflection magnets or quadrupole magnets were restricted to the beam guidance gantry. The measurement gantry, which is of a stand-alone and substantially lighter and smaller design, is, by contrast, not subjected to stress and distorted. This has the further advantage that the device for beam monitoring can be positioned very accurately relative to the isocenter independently of the beam guidance gantry.
A further advantage is that, owing to the smaller mass, the measurement gantry can be positioned more quickly and more accurately. If the measurement gantry is also arranged inside the beam guidance gantry, rotation of the beam guidance gantry does not put at risk a patient and/or operating personnel located inside the measurement gantry. It is thus possible for patient positioning, for example, and, if the measurement gantry also has an imaging device, position verification to be started without, at that time, the beam guidance gantry already being rotated into the angular position later required. If the measurement gantry also comprises a laser system for patient positioning and/or an imaging position verification system, etc. as already mentioned above, these systems are also independent of the angle of rotation, that is to say, they supply information that is not conditional on the position of the beam guidance gantry.
A further advantage relating to the beam guidance gantry is that said gantry becomes less expensive since the positioning accuracy and any positioning errors can be corrected by the independently arranged beam monitoring apparatus.
A further advantage is that the measurement gantry and beam guidance gantry can be designed independently in respect of energy supply, signal processing and the installation of components.
A further advantage is that all the enclosures visible in a patient room can be fitted on the measurement gantry.
In an advantageous embodiment of the gantry system, the measurement gantry comprises apparatus for verifying the patient's position and/or a patient positioning device and/or a laser positioning device. The patient's position is verified shortly before exposure to radiation with, for example, the aid of pairs of x-ray sources and x-ray detectors arranged at an angle. A patient positioning device comprises, for example, a video camera system which matches the patient's position to a required position. A laser positioning device comprises, for example, a laser cross formed by a plurality of laser beams.
An advantage of such embodiments is that an imaging device can be positioned more quickly relative to the patient for patient position verification, since the rotation of the measurement gantry with the imaging devices is independent of the rotation of the beam guidance gantry. A further advantage is the fact that, during the imaging process, the drive and bearing of the beam guidance gantry are not under stress. The independent rotatability of the measurement gantry also, for example, permits orthogonal imaging relative to the irradiation angle. In the case of a continuous, rapid rotation of the measurement gantry, said independent rotatability also permits the capture, from different angles, of a plurality of fluoroscopic images from which, for example, 3D image data sets can be obtained for matching with CT position planning data.
In further embodiments of the gantry system, the measurement gantry and the beam guidance gantry can be installed independently of each other and/or they can be adjusted in their angular position independently of each other and/or they are mechanically, thermally and/or vibrationally separate.
Further advantageous embodiments of the invention are characterized by the features of the subclaims.
BRIEF DESCRIPTION OF THE DRAWINGS
An explanation follows of two exemplary embodiments of the invention with reference to FIGS. 1 to 3 , in which:
FIG. 1 is a diagrammatic representation of a first embodiment of a concentric gantry system in a vertical sectional drawing through its axis of rotation,
FIG. 2 is a front view of the gantry in FIG. 1 , and
FIG. 3 is a diagrammatic representation of a second embodiment of a concentric gantry system in a vertical sectional drawing through its axis of rotation.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a gantry system 1 in a vertical sectional drawing along an axis of rotation 3 . The object of the gantry system 1 is to be able to guide a particle beam 5 such that a patient 7 having tissue that is to be irradiated, for example having a brain tumor, can undergo radiation therapy from any direction of incidence. For this purpose, the patient 7 is positioned, for example on a patient bed 9 , with the tissue to be irradiated in an isocenter 11 of the gantry system 1 . The isocenter 11 preferably lies on the axis of rotation 3 . The direction of incidence can be at any angle to the axis of rotation 3 . For illustrative purposes, an angle of 90° was selected in FIG. 1 . When the gantry system 1 rotates, the direction of incidence rotates about the axis of rotation 3 .
In the exemplary embodiment shown in FIG. 1 , the particle beam is guided by the beam guidance gantry 12 from the beam entry into the gantry system 1 to the patient 7 . The particle beam 5 enters the gantry system 1 on the axis of rotation 3 . The particle beam 5 is deflected from the axis of rotation 3 by a first deflection magnet 13 A before it is deflected by further deflection magnets 13 B and 13 C such that it passes, for example, radially through the isocenter 11 . Further beam guidance elements 15 , for example quadrupole magnets, raster scan magnets, etc. are arranged between the deflection magnets 13 A, 13 B, 13 C. The deflection magnets 13 A, 13 B, 13 C and the beam guidance elements 15 , together with a support structure 16 , form the beam guidance gantry 12 . A bearing device is used for rotation of the beam guidance gantry 12 . The bearing device comprises a first bearing 17 which is arranged in an axial direction, where possible at the level of the centre of gravity of the beam guidance gantry 12 , and also comprises a bearing 19 which is arranged in the region of the beam incoupling. The bearings 17 and 19 are supported on a base 20 . The bearing 17 is preferably in the form of a bearing ring.
Owing to the weight of the beam guidance gantry there is the possibility of distortions which cannot be completely prevented even by a very rigidly designed support structure 16 and which lead to positional variations, for example of the beam guidance elements 15 , and thus to beam displacement.
Arranged concentrically with the beam guidance gantry 12 inside the beam guidance gantry 12 is a measurement gantry 21 . The measurement gantry 21 can rotate independently of the beam guidance gantry 12 . This is made possible by bearings 23 , which are arranged in the direction of the axis of rotation at the level of the bearing 17 of the beam guidance gantry 12 . The bearings 17 and 19 are supported on the base. The bearings 23 are likewise supported on the base 20 , indirectly via the bearing 17 .
In the region of the beam exit 25 of the beam guidance gantry, the measurement gantry 21 has a device 27 for beam monitoring. Apparatus for laser positioning and/or for patient position verification can also be fitted there. The weight of the measurement gantry 21 is much less overall, with the result that deformations depending on the angular position can be very largely prevented. The physical positions of the components supported by the measurement gantry are accordingly reproducible, that is to say, for example the distance to the isocenter 11 is not dependent on the angle of rotation.
The device 27 for beam monitoring measures at least one beam parameter of the administered beam, for example the beam position, the beam intensity and/or the beam energy; the beam parameter or parameters are provided for control of the particle therapy facility and are thus an essential constituent in the administration of radiation therapy. The beam guidance gantry and the measurement gantry thus cooperate during radiation therapy in order to administer a beam with the appropriate parameters. The measurement gantry enables the administered dose and the position of the administered beam to be actively measured. The feedback of this information to, for example, a control unit of the particle therapy facility is required for the irradiation procedure so that, for example, the desired dose can be administered very precisely. This measurement of “primary” parameters of the beam differs from the measurement of radioactive secondary products, for example with a PET machine which, following administration, supplies information concerning the site of the administered dose and cannot be used for control of the particle therapy facility. This latter machine is used far more for quality assurance than for the controlled administration of the irradiation procedure.
The gantry system 1 is preferably designed so that, for radiation therapy, the measurement gantry 21 can be rotated into an angular position in which a measuring unit of the device is penetrated by the particle beam when the beam guidance gantry 12 is correspondingly rotated, in order to measure, in particular, the site and/or the energy and/or the number of administered particles of the beam.
Accordingly, the measuring unit of the device 27 has, for example, a location detector (e.g. multichannel plates) for defining position and/or a dosimeter for measuring intensity.
To illustrate the structure in FIG. 1 , reference is made to FIG. 2 , which is a front view of the gantry system 1 in the direction of the axis of rotation. Visible there are the patient 7 in the isocenter 11 of the gantry system 1 , the beam exit 25 and an outer gantry ring 31 of the beam guidance gantry 12 , as well as the measurement gantry 21 arranged therein with the device 27 for beam monitoring. Also visible there are two flat panel detectors 33 , which are arranged on both sides of the device 27 for beam monitoring and are used for position verification. The x-ray sources required for this purpose are located opposite the patient and are integrated into the measurement gantry 21 and not visible in FIG. 2 .
FIG. 3 shows a further exemplary embodiment of a concentric gantry system 41 , the beam guidance gantry 12 ′ having the components referred to in FIG. 1 , for example deflection magnets 13 A′, 13 B′, 13 C′, bearings 17 ′ and 19 ′, beam exit 25 ′, etc.
Unlike the embodiment shown in FIG. 1 , a measurement gantry 42 is not supported indirectly via the beam guidance gantry 12 ′. Instead there is provided a bearing 43 which is itself arranged on a base 47 of the particle therapy facility. The bearing 43 and the bearings 17 ′ and 19 ′ are thus mechanically separate. This embodiment facilitates complete mechanical, thermal and/or vibrational separation of the measurement gantry and beam guidance gantry 12 ′ and 42 . The measurement gantry 42 again comprises means 45 for imaging, beam monitoring and/or laser positioning. | The invention relates to a gantry system for a particle therapy facility, having a beam guidance gantry which has elements for beam guidance, and having a measurement gantry which has a device for beam monitoring. The measurement gantry and beam guidance gantry are thus of a mutually independent design and are, in particular, arranged in a mutually concentric manner. A gantry system of this kind is inter alia less susceptible to mechanical deviations during rotation of the beam guidance gantry. | 0 |
FIELD OF THE INVENTION
The present invention generally relates to filtration systems for outdoor ponds and more particularly to a filtration system which provides a properly balanced pond habitat while maintaining water clarity, preferably without the use of chemicals and the like.
BACKGROUND OF THE INVENTION
One method of landscaping is to construct a new pond or maintain an existing pond. To obtain the maximum benefit from having such ponds, the ponds should be visually appealing and provide a habitat not only for fish but other creatures such as birds, frogs, butterflies and the like.
Clear water is a feature desired in most ponds so that fish and submerged plants may be viewable. However, maintaining the clarity of the water can become difficult. Algae, in particular free swimming algae, may cause the water to become cloudy. The excessive algae typically occurs when the water contains an excess of nutrients such as ammonia and phosphorous. This ammonia and phosphorous is generally added to pond water by fish waste and fertilizer runoff from the land surrounding the pond. Although aquatic plants may consume a portion of the nutrients, the number of plants is typically insufficient to handle the amount of excessive nutrients in a pond. Algae, which feed on these nutrients, then multiply due to the abundance of nutrients. This multiplication may result in algae "blooms" which cause the pond water to cloud up.
One method of clarifying water is to add such as chlorine chemicals to the water which destroy algae. However, these chemicals may destroy or have a serious impact on the number and growth of aquatic plants and fish. Also, chemicals tend to break down quickly requiring repetitive additions which is expensive.
An additional drawback of using the pond as landscaping is that leaves and other foliage fall onto the surface of the pond, and unless cleaned from the pond, this matter settles to the bottom. At the bottom, the leaves and foliage decompose forming a layer of sludge which may reduce the depth of the pond and also cover any underwater formations. To prevent the settling, leaves may be scooped from the surface of the pond on an almost daily basis; however, such action is labor intensive. In addition, to remove the sludge, the pond may be drained periodically. Draining, however, presents problems such as the temporary storage of fish and any possible damage to aquatic plants while the pond is dry.
It is therefore, an object of the present invention to provide an improved pond filtration system and in particular providing such an improved system which naturally balances the natural habitat in a pond so that water clarity may be maintained.
It is a further object of the present invention to provide an improved pond filtration system which may be operated with low maintenance.
It is a further object of the present invention to provide an improved pond filtration system which maintains water clarity without the use of chemicals.
It is a still further object of the present invention to provide an improved pond filtration system which removes leaves or other foliage which falls into the pond before the leaves and foliage settle to the bottom and decompose. A related object is to provide such a leaf and foliage removal system which may be operated with low maintenance.
It is a further object of the present invention to provide an improved pond filtration system which is hidden from view and may actually contribute to the attractiveness of a pond used as landscaping.
SUMMARY OF THE INVENTION
Accordingly, a filtering system for ponds is provided. The system includes a pond filtering and skimming device having an enclosure defining a first internal chamber and an inlet opening into the first chamber for water to flow into the chamber from the pond. A pump is in fluid communication with the chamber pumps the water out of the chamber thereby creating a flow of the pond water from the chamber inlet to the pump inlet. A filter is disposed within the first chamber to filter at least a portion of any nutrients out of the pond water flowing within the first chamber. The skimmer also preferably includes a removable net disposed between the inlet and filter to entrain any objects which flow into the first chamber along with the pond water.
The pump may pump the water from the skimmer back into the pond but preferably the water is pumped to a bottom portion of an internal second chamber formed by a tank. The water flows upward through a second filter within the second chamber which filters at least a portion of the nutrients out of the water. The water flows upward from the filter and is discharged back into the pond from the tank by flowing outward over a ledge of the tank to form a waterfall.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic side elevational view of a preferred embodiment of a filtration system for ponds;
FIG. 2 is a perspective view with parts removed of a pond skimmer device forming a part of the filtration system for ponds of FIG. 1; and
FIG. 3 is a perspective view with parts removed of a filtering tank forming a part of the filtration system for ponds of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, a preferred embodiment of a pond filtering system constructed in accordance with the present invention is generally indicated at 10. The system 10 is particularly suited to managing the level of algae found in a pond 12 and removing unwanted foliage and other matter which may drop onto the pond surface. The pond 12 may be constructed by the excavation of a pond bed 14 or the pond may be existing. Dirt which is excavated from the bed 14 may be used to form a berm 16 which extends along at least a portion of the periphery of the bed 14.
To retain water in the pond bed 14, the bed is preferably lined with a liner 18 particularly suited for pond water retention. Such a liner 18 may be constructed of fish safe EPDM. Concrete or other materials may also be used, although concrete liners are prone to cracking and the like. When a flexible liner 18 is used, it is preferred that the liner be placed over an underlayment 20 to protect the liner from underlying rocks or roots. The underlayment 20 may be constructed of a wide variety of soft materials such as geotextiles, newspapers, sand or the like.
Rocks 24 and river gravel 26 may be distributed along the entire surface of the liner 18. The rocks 24 serve several purposes including covering up the liner 18, holding the liner against hydrostatic pressure from a high water table and forming a means to get into and out of the pond 12. The river gravel 26 locks the rocks into place and provides surface area for the formation of a biological filter as is described below. Aquatic plants 28a, 28b and 28c may also be used to consume nutrients found in the pond water and add oxygen to the water.
Referring to FIGS. 1 and 2, the filtration system 10 includes a filtering skimmer 30. The skimmer 30 includes a tub like enclosure 34 forming a filtering chamber 35 having a liquid capacity of approximately 30 gallons. The enclosure 34 preferably has a rectangular horizontal cross sectional configuration and is preferably integrally formed as a series of vertically stacked sections 34a which diminish in length and/or width from top to bottom to form a number of horizontal strengthening ribs 36. The ribs 36 strengthen sidewalls 38 of the enclosure 34 so that the enclosure can withstand burial and the freezing of the water in the enclosure during the winter. The enclosure 34 is preferably constructed of high density polyethylene (HDPE) but other materials may be suitable. Such other materials include fiberglass, which due to the strength of fiberglass may eliminate the need for the strengthening ribs 36. In addition the sidewalls 38 may be constructed with a slight draft to facilitate the stacking of multiple enclosures 34.
The enclosure 34 is buried immediately adjacent the pond so that a front sidewall 40 forms a portion of a side 12a of the pond. Formed in the front sidewall 40 is an opening or inlet 44 in which is disposed a skimmer door assembly 46. The skimmer door 46 includes a flange 48 which is attached to the front sidewall 40 and surrounds the inlet 44. Pivotally attached to a horizontal bottom edge 48a of the flange 48 is a flapper door 50. As is well known in skimmer assemblies, the flapper door 50 floats in the water so that movement of water through the inlet 44 causes a pivoting of the flapper door 50 about the bottom edge 48a of the flange 48. When water flows through the inlet 44 into the enclosure 34, the door 50 pivots to an open position to allow such flow. If the water begins to flow from the enclosure through the opening into the pond, the flapper door 50 pivots to a closed position to block this flow.
A large sack-like net 54, preferably constructed of a nylon mesh, is disposed within the enclosure 34 and arranged so that water flowing into the chamber 35 through the inlet 44 flows into an upper opening 55 of the net 54. The upper edge 54a of the net 54 is removably attached to the enclosure 34 by a series of hooks 56 which are disposed on either side of the inlet 44 and on the rear wall 58 opposite the inlet. When water is flowing into the chamber 35 through the inlet 44, leaves and other items which are floating on the surface of the water are carried through the inlet and entrained in the net 54 so that the leaves and items are removed from the pond.
To remove water from the enclosure 34 so that the water flows from the pond through the inlet 44 into the chamber 35, a pump 60 is in fluid communication with the chamber, and the pump is preferably a submerged pump located in close proximity to a generally horizontal floor 64 of the enclosure. The pump 60 creates a flow of water from the pond into the chamber 35 by pumping water in the bottom of the chamber out of the enclosure 34. Discharge piping 66 connected to a discharge 67 of the pump 60 extends upward along the rear wall 58 and turns to exit the enclosure 34 through an exit opening 68 in the rear wall. The discharge piping 66 may also extend upward and over a top edge 70 of the enclosure 34; however, this is not preferred as this may expose the discharge piping to damage, and make it more difficult to hide the exposed discharge pipe. The pump 60 may also be located outside the enclosure 34 with piping providing fluid communication between the pump and chamber 35.
The enclosure 34 is buried so that when the surface 74 of the pond is at a desired level, the pond surface 74 is at the same level as the top of the inlet 44. As the desired level of the surface 74 may range over a certain distance, the inlet 44 is sized so that as long as the pond surface is within the desired range, water and the floating leaves, etc. may flow through the opening 44 into the enclosure 34. Also, to insure that leaves and other matter which are deposited on the pond surface 74 can flow into the chamber 35 without catching on the flange 48, the enclosure 34 should be buried so that the desired lower level of the pond is a minimum of 2" above the lower edge 48a of the flange 48. In addition, the height of the inlet 44 should be sized so that the horizontal upper edge 48b of the flange 48 is equal to or higher than the desired upper level of the pond surface 74.
To remove the need to form a seal between the discharge piping 66 and the rear wall 58 of the enclosure 34 as the piping passes out of the enclosure, the exit opening 68 is preferably formed at a location higher than the desired upper level of the pond surface and upper edge 48b of the flange. It is also contemplated that a seal may be created between the piping 66 and rear wall 58 should such a seal be necessary.
To prevent a situation where the water level, for whatever reason, drops below the lower edge 48a of the flange so that water no longer flows into the chamber 34 through the inlet 44, with the pump 60 then pumping the chamber dry which may damage the pump, a float type switch and valve assembly 78 for selectively introducing water from an independent water fill source (not shown) is located within the chamber 35. Preferably the mechanical switch valve assembly 78 is disposed on the rear wall 58 and is operatively connected to the water source such as an underground irrigation pipe or underground polyethylene pipe that originates at an outdoor faucet. The switch element 78a is adjusted so that if the water level in the chamber 35 drops below a level approximately 2" above the bottom edge 48a of the flange 48, the water fill valve element 78b is mechanically opened. Alternatively, the pump 60 can be purchased or retrofit with a pressure sensitive switch 60a which deactivates the pump when the chamber 35 is pumped dry.
To filter nutrients out of the pond water after the water has flowed through the net 54 and before the water is pumped out of the chamber 35, a biological filter arrangement 80 is disposed between the net and pump 60. The biological filter 80 preferably includes at least one horizontally extending filter mat 82 which provides a large surface area for the attachment of filtering bacteria 84. Many different types of filter mats may be used in the biological filter 80, however, low density material such as nonwoven polyester/nylon blend filters manufactured by AMERICO of Acworth, Ga. have been found to be particularly efficient. The filtering bacteria 84 may be deposited on the filter mat 82 by the pouring of such bacteria directly on the mat 82. Such filtering bacteria may be obtained from several sources such as AQUA BACTA-AID from Water Quality Science International of Bolivar, Mo. and AQUA CLEAR from Aquascape Designs, Inc., of Wheaton, Ill.
The filter 80 is preferably composed of a plurality of the filter mats 82 preferably horizontally supported by the ribs 36 formed in the enclosure 34 with the mats arranged in a vertically spaced series. Each of the filter mats 82 may be 1 to 11/2 inches thick.
A lid 86 is sized to cover the opening 88 formed by a top edge of the side walls 38. A lid 86 is preferably strong enough to support the weight of a person but light enough to be easily removed to allow access to the chamber 35 and net 54. The lid 86 may also be formed to appear as earth or earth mixed with rocks to contribute to the attractiveness of the pond 12.
Referring to FIGS. 1 and 3, discharge from the skimmer 30 may be conveyed to the pond 12. However, in the preferred method, the discharge is conveyed to a filtering tank indicated generally at 100. Fluid communication between the tank 100 and the discharge piping 66 of the skimmer 30 is provided by a water conduit 102 which is preferably a flexible polyethylene pipe but may also be rigid piping or the like. The filtering tank 100 may be placed in close proximity to the pond 12 so that discharge from the tank flows into the pond. Optionally, the tank 100 can be positioned away from the pond's edge, and the discharge from the waterfall's lip 142 used to feed an EPDM-lined and rock filled stream. The stream is then used to guide the water back into the pond 12, oxygenating the water through additional exposure to the atmosphere and through additional water falls, depending on how the berm 16 is configured.
Preferably, the tank 100 is placed across the pond 12 from the skimmer 30 so that a current crossing the pond is formed by the flow from the tank 100 and into the skimmer 30. It is believed that such a current provides the optimal current for directing floating leaves and other items into the skimmer 30.
The filtering tank 100 includes a lower compartment 106 which is integrally attached to a peripheral rock ledge 108. The compartment 106 is formed with a lower, generally horizontal floor 110, which is integrally attached to generally vertically extending side walls 112.
The side walls 112 may be formed with a slight draft to facilitate stacking of a number of tanks 100. The side walls 112 are preferably arranged to form a frustotriangular shaped horizontal cross section. A front side wall 116, which is to be directed toward the pond 12, is the shorter of the side walls to aesthetically minimize the exposure of the tank 100 to the pond.
The ledge 108 includes a horizontal flange portion 118 which extends outward from about the periphery of an upper edge 112a of the side wall 112. A containing lip 120 to forwardly direct water being discharged from the compartment 106 extends upwards from an outer end 118a of the horizontal flange 118 around the side 118a and rear 118b sections of the flange.
The conduit 102 conveying discharged pond water from the skimmer 34 is sealing connected to a down pipe 124 by a fluid tight coupling 126 sealingly disposed in one of the side walls 112. An outlet 128 of the down pipe is positioned in a lower portion 130 of the compartment 106. Horizontally extending above the outlet 128 is a biological filtering medium 132. The filtering medium 132 is preferably filter mats 136 similar in construction to the filter mats in the skimmer 30. However, the filtering medium 132 may also be plastic bioballs, lava rock, or the like. The filtering medium 132 is supported on a horizontal extending grate 138 so that a distribution chamber 140 is formed below the filtering medium 136 with the outlet 128 of the down pipe 124 being within the distribution chamber. The grate 138 may be composed of a non-corrosive material such as plastic or fiberglass or the like and is supported above the floor 110 by scalloped indentations 144 formed at the cornered intersections of the side walls 112 and floor 110.
The tank 100 is preferably buried in the bordering berm 16 so that the side walls 112 are hidden but the lip 142 of the ledge 108 extends outward over the edge of the pond. The pond liner 18 may extend up along the front sidewall 116 to prevent leakage. Water flowing upward from the compartment 106 is directed forward by the containing lip 120 to form a waterfall into the pond which is both attractive and also adds oxygen to the pond 12. A drip shield 148 extends along a lower surface of the lip 142.
The plants 24b and 24c may be placed within the tank 100. For example, plants 24b such as cattails or water iris may be rooted directly in the filtering medium 132 particularly when gravel or lava rock is used as the medium, or the plants may be placed in containers which will likely reduce their effectiveness as the roots would be less exposed to the flowing water. Also, floating plants 24c, such as water hyacinth or water lettuce, may be used.
Referring to FIGS. 1, 2 and 3, in operation, the skimmer 30 is buried so that the front sidewall 40 forms a portion of the pond bed 12, and the tank 100 is buried adjacent the pond 12, or at the head of a stream that feeds the pond 12. The skimmer 30 is also buried so that the front inlet 44 is horizontally positioned to span the desired range of the level of the pond surface 74. Filter mats 82 are placed in a horizontal position in the skimmer 30, and filter mats 132 are placed in a horizontal position in the tank 100. Nutrient consuming bacteria 84 may then be sprinkled onto the filter mats 82 and filter mats 132. Fluid communication may then be established between the skimmer 30 and tank 100 by connecting the two with the conduit 102.
The net 54 is then removably attached to the sidewalls 38 of the skimmer 30 so that the opening 55 of the net surrounds the inlet 44. Then, the pond bed 14 is filled with water until the pond surface 74 reaches the level of the inlet 44 and water flows into the chamber 35 of the skimmer 30. The pump 60 may then be activated.
Water is sucked into an inlet 152 of the pump 60 to cause a flow of water within the chamber 35 from the inlet 44 through the net 54 and filtering arrangement 80 to the pump 60. As the water flows through the net 54, matter, such as leaves, etc. in the water is entrained in the net. As the water flows through the filtering arrangement 80, the bacteria 84 on the mats 82 consume nutrients thereby depriving algae of a food source which reduces the amount of algae. Bacteria 84 may also be added to the pond water in the pond 12 with the bacteria anchoring to the rocks 24 and gravel 26 where this bacteria also consumes excess nutrients.
In the skimmer 30 and tank 100, the rate of consumption of the nutrients by the bacteria 84 is at least partially dependent on the level of oxygen in the water flowing through the mats 82 with higher amounts of oxygen yielding better nutrient consumption. Because water at and in close proximity to the surface of the pond typically has the highest level of oxygen and the water flowing within the chamber 35 is skimmed off the top of the pond 12, the bacteria 84 is assured of being supplied with water having high oxygen levels.
In addition to entraining leaves, the flow of water into the skimmer 30 collects dust and dissolved organic compounds (DOCS) which is present in every pond from fish waste and pond debris. These DOCS may be found in the water adjacent the pond surface 74 and if not removed, may form an unsightly scum. The flow of water in the chamber 35, delivers the DOCS to the filtering arrangement 80 and/or filtering medium 132.
Water entering the pump inlet 152 is transferred by the pump 60 through the conduit 102 to the tank 100. Water entering the tank 100 flows within the distribution chamber 140 and upward through the filtering medium 132. The bacteria 84 in the filtering medium 132 consume additional amounts of nutrients, and the high oxygen levels in the water promote maximum nutrient consumption.
Water flows upward from the mats 136 of the filtering medium 132 to the upper edge 112a of the sidewalls 112 and outward over the horizontal flange 118 of the ledge 108. The containment lip 120 directs the flowing water forward over the lip 142 of the flange 118 where the water is discharged from the tank 100 to form a waterfall.
Periodically, such as weekly or monthly, depending on the season and the amount of seeds and leaves blowing into the pond 12, the lid 86 of the skimmer 30 may be removed and the net 54 temporarily removed from the chamber 35 of the skimmer 30 and the entrained matter cleaned from the net.
A specific embodiment of the novel filtration system for ponds according to the present invention has been described for the purposes of illustrating the manner in which the invention may be made and used. It should be understood that implementation of other variations, and modifications of the invention in its various aspects will be apparent to those skilled in the art, and that the invention is not limited by the specific embodiment described. It is therefore contemplated to cover by the present invention any and all modifications, variations, or equivalents that fall within the true spirit and scope of the basic underlying principles disclosed and claimed herein. | Accordingly, a filtering system for ponds is provided. The system includes a pond filtering and skimming device having defining a first internal chamber. Disposed within the chamber is a removable net disposed between the inlet and filter to entrain any objects which flow into the first chamber along with the pond water and a biological filter to filter at least a portion of any nutrients out of the pond water flowing within the first chamber. Water from the first internal chamber is preferably pumped to a bottom portion of an internal second chamber formed by a tank. The water flows upward through a second filter within the second chamber which filters at least a portion of the nutrients out of the water. The water flows upward from the filter and is discharged back into the pond from the tank to form a waterfall by flowing outward over a ledge of the tank. | 8 |
CROSS-REFERENCES TO RELATED APPLICATIONS
This application claims priority to U.S. Provisional Application No. 61/663,234, filed Jun. 22, 2012, which is incorporated in its entirety herein for all purposes.
BACKGROUND OF THE INVENTION
High performance down-converting phosphor technologies will play a prominent role in the next generation of visible light emission, including high efficiency solid-state white lighting (SSWL). In addition, such technologies are also applicable to near infrared (NIR) and infrared (IR) light emitting technologies. Down-conversion from ultraviolet (UV) or blue light emitting semiconductor light emitting diodes (LEDs) into blue, red and green wavelengths offers a fast, efficient and cost-effective path for delivering commercially attractive white light sources. Unfortunately, existing rare-earth activated phosphors or halophosphates, which are currently the primary source for solid-state down-conversion, were originally developed for use in fluorescent lamps and cathode ray tubes (CRTs), and therefore have a number of critical shortfalls when it comes to the unique requirements of SSWL. As such, while some SSWL systems are available, poor power efficiency (<20 light lumens/watt (lm/W)), poor color rendering (Color Rendering Index (CRI)<75) and extremely high costs (>$200/kilolumen (klm)) limit this technology to niche markets such as flashlights and walkway lighting.
Furthermore, LEDs often suffer from reduced performance as a result of internal reflection of photons at the chip/coating interface. Typically, LEDs are encapsulated or coated in a polymeric material (which may comprise phosphors) to provide stability to the light-emitting chip. Currently these coatings are made by using an inorganic or organic coating that has a very different refractive index than the base material (i.e., the chip), which results in a detrimental optical effect due to the refractive index mismatch at the interface between the two materials. In addition, the temperature of the LED can reach in excess of 100° C. To allow for the expansion and contraction that can accompany this temperature rise, a compliant polymeric layer (e.g., silicone) is often placed in contact with the chip. In order to provide additional stability to the LED, this compliant layer is often further coated with a hard shell polymer.
The resulting LED structure suffers loss of light at the chip/compliant polymer interface due to the lower refractive index of the polymer coating in relation to the LED. However, if the refractive index of the compliant layer is increased, even greater loss will occur due at the high refractive index/low refractive index interface between the compliant polymer and the hard shell polymer due to internal reflection.
There are several critical factors which result in poor power efficiencies when using traditional inorganic phosphors for SSWL. These include: total internal reflection at the LED-chip and phosphor layer interface resulting in poor light extraction from the LED into the phosphor layer; poor extraction efficiency from the phosphor layer into the surroundings due to scattering of the light generated by the phosphor particles as well as parasitic absorption by the LED chip, metal contacts and housing; broad phosphor emission in the red wavelength range resulting in unused photons emitted into the near-IR; and poor down-conversion efficiency of the phosphors themselves when excited in the blue wavelength range (this is a combination of absorption and emission efficiency). While efficiencies improve with UV excitation, additional loss due to larger Stokes-shifted emission and lower efficiencies of LEDs in the UV versus the blue wavelength range makes this a less appealing solution overall.
As a result, poor efficiency drives a high effective ownership cost. The cost is also significantly impacted from the laborious manufacturing and assembly process to construct such devices, for example the heterogeneous integration of the phosphor-layer onto the LED-chip during packaging (DOE and Optoelectronics Industry Development Association “Light emitting diodes (LEDs) for general illumination,” Technology Roadmap (2002)). Historically, blue LEDs have been used in conjunction with various band edge filters and phosphors to generate white light. However, many of the current filters allow photon emission from the blue end of the spectrum, thus limiting the quality of the white LED. The performance of the devices also suffer from poor color rendering due to a limited number of available phosphor colors and color combinations that can be simultaneously excited in the blue. There is a need therefore for efficient nanocomposite filters that can be tailored to filter out specific photon emissions in the visible (especially the blue end), ultraviolet and near infrared spectra.
While some development of organic phosphors has been made for SSWL, organic materials have several insurmountable drawbacks that make them unlikely to be a viable solution for high-efficiency SSWL. These include: rapid photodegradation leading to poor lifetime, especially in the presence of blue and near-UV light; low absorption efficiency; optical scattering, poor refractive index matching at the chip-interface, narrow and non-overlapping absorption spectra for different color phosphors making it difficult or impossible to simultaneously excite multiple colors; and broad emission spectra. There exists a need therefore for polymeric layers that aid production of high quality, high intensity, white light. Surprisingly, the present invention meets this and other needs.
BRIEF SUMMARY OF THE INVENTION
In some embodiments, the present invention provides a quantum dot binding-ligand having a siloxane polymer including a plurality of monomer repeat units. The quantum dot binding-ligand also includes a plurality of amine or carboxy binding groups each covalently attached to one of the monomer repeat units, thereby forming a first population of monomer repeat units. The quantum dot binding-ligand also includes a plurality of solubilizing groups each covalently attached to one of the monomer repeat units, thereby forming a second population of monomer repeat units.
In some embodiments, the quantum dot binding ligand has the structure of formula I:
wherein each R 1 can independently be C 1-20 alkyl, C 1-20 heteroalkyl, C 2-20 alkenyl, C 2-20 alkynyl, cycloalkyl or aryl, each optionally substituted with one or more —Si(R 1a ) 3 groups; each R 1a can independently be C 1-6 alkyl, cycloalkyl or aryl; each L can independently be C 3-8 alkylene, C 3-8 heteroalkylene, C 3-8 alkylene-O—C 2-8 alkylene, C 3-8 alkylene-(C(O)NH—C 2-8 alkylene) q , C 3-8 heteroalkylene-(C(O)NH—C 2-8 alkylene) q , or
C 3-8 alkylene-O—C 1-8 alkylene-(C(O)NH—C 2-8 alkylene) q ; each R 2 can independently be NR 2a R 2b or C(O)OH; each of R 2a and R 2b can independently be H or C 1-6 alkyl; each R 3 can independently be C 1-20 alkyl, C 2-20 alkenyl, C 2-20 alkynyl, cycloalkyl or aryl; each R 4 can independently be C 8-20 alkyl, C 8-20 heteroalkyl, cycloalkyl or aryl, each optionally substituted with one or more —Si(R 1a ) 3 groups; each R 5 can independently be C 1-20 alkyl, C 2-20 alkenyl, C 2-20 alkynyl, -L-(R 2 ) q , cycloalkyl or aryl; subscript m is an integer from 5 to 50; subscript n is an integer from 0 to 50; and subscript q is an integer from 1 to 10, wherein when subscript n is 0, then R 1 can be C 8-20 alkyl, C 8-20 heteroalkyl, C 8-20 alkenyl, C 8-20 alkynyl, cycloalkyl or aryl, each optionally substituted with one or more —Si(R 1a ) 3 groups.
In some embodiments, the present invention provides a method of making a quantum dot binding-ligand of formula Ib:
The method of making the quantum dot binding-ligand of formula I includes forming a reaction mixture having water and a compound of formula II:
to afford a compound of formula III:
The method also includes forming a reaction mixture of (R 5 ) 3 SiOM and the compound of formula III, to afford a compound of formula IV:
The method also includes forming a reaction mixture of the compound of formula IV, a catalyst, and CH 2 ═CH(CH 2 ) p NR 2a R 2b , thereby forming the compound of formula I. For formulas Ib, II, III and IV, each R 1 can independently be C 8-20 alkyl, C 8-20 alkenyl, C 8-20 alkynyl, cycloalkyl or aryl; each R 2a and R 2b can independently be H or C 1-6 alkyl; each R 5 can independently be C 1-20 alkyl, C 2-20 alkenyl, C 2-20 alkynyl, C 3-8 alkyl-NR 2a R 2b , cycloalkyl or aryl; subscript m can be an integer from 5 to 50; M can be hydrogen or a cation; and subscript p can be an integer of from 1 to 6.
In some embodiments, the present invention provides a composition of a quantum dot binding-ligand of the present invention, and a first population of light emitting quantum dots (QDs).
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention.
FIG. 1 shows the synthesis of one type of quantum dot binding-ligand of the present invention by partial hydrosilylation of a commercially available siloxane with an alkene, followed by hydrosilylation of the remaining silane groups with an alkene-amine.
FIG. 2 shows the synthesis of another type of quantum dot binding-ligand of the present invention by condensation of a long-chain alkyl functionalized dichlorosilane (RSi(Cl) 2 H) with water, followed by end-capping the terminal chloro groups of the siloxane polymer, and then hydrosilylation of the silane groups with a suitable alkeneamine
FIG. 3 shows the synthesis of another type of quantum dot binding-ligand of the present invention prepared by separating any bis-substituted chlorosilane (1a) prepared in the first step, followed by conversion to a silanol (1b), and then reaction with the siloxane polymer (2) to form the end-capped siloxane polymer (3a). The remaining silane groups are reacted with a suitable alkene and Karstedt's catalyst to prepare the final product (4a), having two additional alkyl-amine groups and four additional long-chain alkyl groups compared to the product of the scheme in FIG. 2 .
FIG. 4 shows the Laser HALT data for PSAW-1:1 versus epoxy silicone hybrid (ESH) quantum dot compositions, demonstrating improved lifetime for the PSAW-1:1-QD compositions for both red (R) and green (G) light.
FIG. 5 shows the synthesis of a silyl-modified binding ligand by hydrosilylation of a siloxane polymer with the trialkylsilyl-modified alkene, following by hydrosilylation with an alkene-amine to afford the trialkylsilyl-modified siloxane polymer.
FIG. 6 shows the synthesis of a siloxane homopolymer having both the carboxylic acid binding group and the long-alkyl solubilizing group on a single monomer. First, trichlorosilane is modified with a long-chain alkyl via a Grignard reaction. The product is then polymerized under condensation conditions to afford a polysilane, which is then modified with the carboxylic acid binding group via hydrosilylation with Karstedt's catalyst.
FIG. 7 shows an alternative synthesis to the compound shown in FIG. 7 . After modifying the trichlorosilane with the alkyl solubilizing group, the silyl group is reacted with a precursor to the bis-carboxylic acid binding group under hydrosilylation conditions using Karstedt's catalyst. The resulting dichlorosilane is polymerized under condensation conditions to form the product homopolymer.
FIG. 8 shows the synthesis of a siloxane copolymer with a bis-amine binding group on one monomer and an alkyl solubilizing group on the second monomer. The siloxane polymer is prepared starting with a polysilane that is partially modified with a long-chain alkene via hydrosilylation. The remaining silyl groups are reacted with a precursor to the bis-amine binding group (allyl dimethyl succinate), again via hydrosilylation with Karstedt's catalyst. The dimethyl succinate is then converted to an amine by reaction with 1,2-diaminoethane to afford the product ligand.
FIG. 9 shows the synthesis of a siloxane homopolymer having both the bis-amine binding group and the long-alkyl solubilizing group on a single monomer. The synthesis follows that described above for FIG. 8 , with the additional step of converting the dimethyl succinate to an amine by reaction with 1,2-diaminoethane.
DETAILED DESCRIPTION OF THE INVENTION
I. General
The present invention provides siloxane amine waxes (SAW) for binding to quantum dots. The ligands provide greater stability for the quantum dots due to a plurality of amine or carboxy binding groups.
II. Definitions
“Siloxane polymer” or “polysiloxanes” refers to a polymer having a monomer repeat unit of the formula: —Si(R 2 )O—. The R groups of the siloxane polymer can be the same or different, and can be any suitable group, including, but not limited to, hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, aryl and heteroaryl. When both R groups are other than hydrogen, the siloxane polymer can be referred to as a “silicone.” The siloxane polymers can be linear, branched or cyclic. The siloxane polymer can include a single type of monomer repeat unit, forming a homopolymer. Alternatively, the siloxane polymer can include two or more types of monomer repeat units to form a copolymer that can be a random copolymer or a block copolymer.
“Solubilizing group” refers to a substantially non-polar group that has a low solubility in water and high solubility in organic solvents such as hexane, pentane, toluene, benzene, diethylether, acetone, ethyl acetate, dichloromethane (methylene chloride), chloroform, dimethylformamide, and N-methylpyrrolidinone. Representative solubilizing groups include long-chain alkyl, long-chain heteroalkyl, long-chain alkenyl, long-chain alkynyl, cycloalkyl and aryl.
“Amine binding group” refers to an amine having the formula —NR 2 . The R groups attached to the nitrogen atom can be any suitable group, including hydrogen and alkyl. Moreover, the R groups can be the same or different.
“Carboxy binding group” refers to a carboxylic acid group: C(O)OH.
“Alkyl” refers to a straight or branched, saturated, aliphatic radical having the number of carbon atoms indicated. Alkyl can include any number of carbons, such as C 1-2 , C 1-3 , C 1-4 , C 1-5 , C 1-6 , C 1-7 , C 1-8 , C 1-9 , C 1-10 , C 1-12 , C 1-14 , C 1-16 , C 1-18 , C 1-20 , C 8-20 , C 12-20 , C 14-20 , C 16-20 , and C 18-20 . For example, C 1-6 alkyl includes, but is not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, hexyl, etc. Other alkyl groups include octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane, and icosane. Alkyl groups can be substituted or unsubstituted.
“Long-chain alkyl groups” are alkyl groups, as defined above, having at least 8 carbon chain atoms. Long-chain alkyl groups can include any number of carbons, such as C 8-20 , C 12-20 , C 14-20 , C 16-20 , or C 18-20 . Representative groups include, but are not limited to, octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane, and icosane. Long-chain alkyl groups can also be substituted with silane groups.
“Alkylene” refers to a straight or branched, saturated, aliphatic radical having the number of carbon atoms indicated, and linking at least two other groups. The alkylene can link to 2, 3, 4, or more groups, and be divalent, trivalent, tetravalent, or multi-valent. The groups linked to the alkylene can be linked to the same atom or different atoms of the alkylene group. For instance, a straight chain alkylene can be the bivalent radical of —(CH 2 ) n —, where n is 1, 2, 3, 4, 5 or 6. Representative alkylene groups include, but are not limited to, methylene, ethylene, propylene, isopropylene, butylene, isobutylene, sec-butylene, pentylene and hexylene. Alkylene groups can be substituted or unsubstituted.
“Alkylamine binding group” refers to an amine linked to an alkyl, as described above, and generally having the formula —C 1-20 alkyl-NR 2 . The alkyl moiety of the alkylamine binding group is linked to the siloxane polymer of the present invention. Any suitable alkyl chain is useful. The R groups attached to the nitrogen atom can be any suitable group, including hydrogen and alkyl. Moreover, the R groups can be the same or different.
“Heteroalkyl” refers to an alkyl group of any suitable length and having from 1 to 5 heteroatoms such as N, O and S. Additional heteroatoms can also be useful, including, but not limited to, B, Al, Si and P. The heteroatoms can also be oxidized, such as, but not limited to, —S(O)— and —S(O) 2 —. For example, heteroalkyl can include ethers (ethyleneoxy and poly(ethyleneoxy)), thioethers and alkyl-amines. The heteroatom portion of the heteroalkyl can replace a hydrogen of the alkyl group to form a hydroxy, thio or amino group. Alternatively, the heteroatom portion can be the connecting atom, or be inserted between two carbon atoms.
“Long-chain heteroalkyl groups” are heteroalkyl groups, as defined above, having at least 8 chain atoms. Long-chain heteroalkyl groups can include any number of chain atoms, such as C 8-20 , C 12-20 , C 14-20 , C 16-20 , or C 18-20 .
“Heteroalkylene” refers to a heteroalkyl group, as defined above, linking at least two other groups. The two moieties linked to the heteroalkylene can be linked to the same atom or different atoms of the heteroalkylene.
“Alkenyl” refers to a straight chain or branched hydrocarbon having at least 2 carbon atoms and at least one double bond. Alkenyl can include any number of carbons, such as C 2 , C 2-3 , C 2-4 , C 2-5 , C 2-6 , C 2-7 , C 2-8 , C 2-9 , C 2-10 , C 2-12 , C 2-14 , C 2-16 , C 2-18 , C 2-20 , C 8-20 , C 12-20 , C 14-20 , C 16-20 , and C 18-20 . Alkenyl groups can have any suitable number of double bonds, including, but not limited to, 1, 2, 3, 4, 5 or more. Examples of alkenyl groups include, but are not limited to, vinyl (ethenyl), propenyl, isopropenyl, 1-butenyl, 2-butenyl, isobutenyl, butadienyl, 1-pentenyl, 2-pentenyl, isopentenyl, 1,3-pentadienyl, 1,4-pentadienyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 1,3-hexadienyl, 1,4-hexadienyl, 1,5-hexadienyl, 2,4-hexadienyl, or 1,3,5-hexatrienyl. Alkenyl groups can be substituted or unsubstituted.
“Long-chain alkenyl groups” are alkenyl groups, as defined above, having at least 8 carbon chain atoms. Long-chain alkenyl groups can include any number of carbons, such as C 8-20 , C 12-20 , C 14-20 , C 16-20 , or C 18-20 . Representative groups include, but are not limited to, octene, nonene, decene, undecene, dodecene, tridecene, tetradecene, pentadecene, hexadecene, heptadecene, octadecene, nonadecene, and icosene. The long-chain alkenyl groups can have one or more alkene groups.
“Alkynyl” refers to either a straight chain or branched hydrocarbon having at least 2 carbon atoms and at least one triple bond. Alkynyl can include any number of carbons, such as C 2 , C 2-3 , C 2-4 , C 2-5 , C 2-6 , C 2-7 , C 2-8 , C 2-9 , C 2-10 , C 2-12 , C 2-14 , C 2-16 , C 2-18 , C 2-20 , C 8-20 , C 12-20 , C 14-20 , C 16-20 , and C 18-20 . Examples of alkynyl groups include, but are not limited to, acetylenyl, propynyl, 1-butyryl, 2-butyryl, isobutynyl, sec-butyryl, butadiynyl, 1-pentynyl, 2-pentynyl, isopentynyl, 1,3-pentadiynyl, 1,4-pentadiynyl, 1-hexynyl, 2-hexynyl, 3-hexynyl, 1,3-hexadiynyl, 1,4-hexadiynyl, 1,5-hexadiynyl, 2,4-hexadiynyl, or 1,3,5-hexatriynyl. Alkynyl groups can be substituted or unsubstituted.
“Long-chain alkynyl groups” are alkynyl groups, as defined above, having at least 8 carbon chain atoms. Long-chain alkynyl groups can include any number of carbons, such as C 8-20 , C 12-20 , C 14-20 , C 16-20 , or C 18-20 . Representative groups include, but are not limited to, octyne, nonyne, decyne, undecyne, dodecyne, tridecyne, tetradecyne, pentadecyne, hexadecyne, heptadecyne, octadecyne, nonadecyne, and icosyne. The long-chain alkynyl groups can have one or more alkyne groups.
“Cycloalkyl” refers to a saturated or partially unsaturated, monocyclic, fused bicyclic or bridged polycyclic ring assembly containing from 3 to 12 ring atoms, or the number of atoms indicated. Cycloalkyl can include any number of carbons, such as C 3-6 , C 4-6 , C 5-6 , C 3-8 , C 4-8 , C 5-8 , C 6-8 , C 3-9 , C 3-10 , C 3-11 , C 3-12 , C 6-10 , or C 6-12 Saturated monocyclic cycloalkyl rings include, for example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cyclooctyl. Saturated bicyclic and polycyclic cycloalkyl rings include, for example, norbornane, [2.2.2]bicyclooctane, decahydronaphthalene and adamantane. Cycloalkyl groups can also be partially unsaturated, having one or more double or triple bonds in the ring. Representative cycloalkyl groups that are partially unsaturated include, but are not limited to, cyclobutene, cyclopentene, cyclohexene, cyclohexadiene (1,3- and 1,4-isomers), cycloheptene, cycloheptadiene, cyclooctene, cyclooctadiene (1,3-, 1,4- and 1,5-isomers), norbornene, and norbornadiene. When cycloalkyl is a saturated monocyclic C 3-8 cycloalkyl, exemplary groups include, but are not limited to cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl. When cycloalkyl is a saturated monocyclic C 3-6 cycloalkyl, exemplary groups include, but are not limited to cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl. Cycloalkyl groups can be substituted or unsubstituted.
“Alkyl-cycloalkyl” refers to a radical having an alkyl component and a cycloalkyl component, where the alkyl component links the cycloalkyl component to the point of attachment. The alkyl component is as defined above, except that the alkyl component is at least divalent, an alkylene, to link to the cycloalkyl component and to the point of attachment. In some instances, the alkyl component can be absent. The alkyl component can include any number of carbons, such as C 1-6 , C 1-2 , C 1-3 , C 1-4 , C 1-5 , C 2-3 , C 2-4 , C 2-5 , C 2-6 , C 3-4 , C 3-5 , C 3-6 , C 4-5 , C 4-6 and C 5-6 . The cycloalkyl component is as defined within. Exemplary alkyl-cycloalkyl groups include, but are not limited to, methyl-cyclopropyl, methyl-cyclobutyl, methyl-cyclopentyl and methyl-cyclohexyl.
“Aryl” refers to an aromatic ring system having any suitable number of ring atoms and any suitable number of rings. Aryl groups can include any suitable number of ring atoms, such as, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16 ring atoms, as well as from 6 to 10, 6 to 12, or 6 to 14 ring members. Aryl groups can be monocyclic, fused to form bicyclic or tricyclic groups, or linked by a bond to form a biaryl group. Representative aryl groups include phenyl, naphthyl and biphenyl. Other aryl groups include benzyl, having a methylene linking group. Some aryl groups have from 6 to 12 ring members, such as phenyl, naphthyl or biphenyl. Other aryl groups have from 6 to 10 ring members, such as phenyl or naphthyl. Some other aryl groups have 6 ring members, such as phenyl. Aryl groups can be substituted or unsubstituted.
“Alkyl-aryl” refers to a radical having an alkyl component and an aryl component, where the alkyl component links the aryl component to the point of attachment. The alkyl component is as defined above, except that the alkyl component is at least divalent, an alkylene, to link to the aryl component and to the point of attachment. The alkyl component can include any number of carbons, such as C 0-6 , C 1-2 , C 1-3 , C 1-4 , C 1-5 , C 1-6 , C 2-3 , C 2-4 , C 2-5 , C 2-6 , C 3-4 , C 3-5 , C 3-6 , C 4-5 , C 4-6 and C 5-6 . In some instances, the alkyl component can be absent. The aryl component is as defined above. Examples of alkyl-aryl groups include, but are not limited to, benzyl and ethyl-benzene. Alkyl-aryl groups can be substituted or unsubstituted.
“Silane” or “silyl” refers to a silicon atom having several substituents, and generally having the formula —SiR 3 . The R groups attached to the silicon atom can be any suitable group, including, but not limited to, hydrogen, halogen and alkyl. Moreover, the R groups can be the same or different.
“Forming a reaction mixture” refers to combining at least two components in a container under conditions suitable for the components to react with one another and form a third component.
“Catalyst” refers to a transition metal catalyst capable of performing a hydrosilylation reaction. Representative catalysts include palladium and platinum catalysts such as Karstedt's catalyst. Other catalysts are useful in the present invention.
“Cation” refers to metal and non-metal ions having at least a 1+ charge. Metals useful as the metal cation in the present invention include the alkali metals, alkali earth metals, transition metals and post-transition metals. Alkali metals include Li, Na, K, Rb and Cs. Non-metal cations can be formed from a variety of groups including quaternary nitrogen groups such as ammonium ions, R 4 N + , wherein the R groups can be the same or different, and can be any suitable group, including, but not limited to, hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, aryl and heteroaryl.
“Quantum dot” or “nanocrystal” refers to nanostructures that are substantially monocrystalline. A nanocrystal has at least one region or characteristic dimension with a dimension of less than about 500 nm, and down to on the order of less than about 1 nm. As used herein, when referring to any numerical value, “about” means a value of ±10% of the stated value (e.g. about 100 nm encompasses a range of sizes from 90 nm to 110 nm, inclusive). The terms “nanocrystal,” “quantum dot,” “nanodot,” and “dot,” are readily understood by the ordinarily skilled artisan to represent like structures and are used herein interchangeably. The present invention also encompasses the use of polycrystalline or amorphous nanocrystals.
III. Quantum Dot Binding-Ligands
The present invention provides a siloxane amine wax (SAW) for binding to quantum dots (QDs) and related materials. The SAW materials of the present invention contain a waxy component (long-chain alkyl) and a plurality of amine or carboxy groups capable of binding to QDs, improving stability of the resulting ligand-QD complex.
In some embodiments, the present invention provides a quantum dot binding-ligand having a siloxane polymer including a plurality of monomer repeat units. The quantum dot binding-ligand also includes a plurality of amine or carboxy binding groups each covalently attached to one of the monomer repeat units, thereby forming a first population of monomer repeat units. The quantum dot binding-ligand also includes a plurality of solubilizing groups each covalently attached to one of the monomer repeat units, thereby forming a second population of monomer repeat units.
In some embodiments, the present invention provides a quantum dot binding-ligand having a siloxane polymer including a plurality of monomer repeat units. The quantum dot binding-ligand also includes a plurality of alkylamine binding groups each covalently attached to one of the monomer repeat units, thereby forming a first population of monomer repeat units. The quantum dot binding-ligand also includes a plurality of solubilizing or hydrophobic groups each covalently attached to one of the monomer repeat units, thereby forming a second population of monomer repeat units.
The siloxane polymer can be any siloxane polymer having a waxy component and a binding component. The waxy component can be any solubilizing or hydrophobic group. In some embodiments, the solubilizing or hydrophobic group can be a long-chain alkyl group, a long-chain alkenyl group, a long-chain alkynyl group, a cycloalkyl or an aryl.
In some embodiments, the solubilizing group or waxy component can be a long-chain alkyl. In some embodiments, each long-chain alkyl group can be octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane, or icosane. In some embodiments, each long-chain alkyl group can be hexadecane, heptadecane, octadecane, nonadecane, or icosane. In some embodiments, each long-chain alkyl group can be hexadecane, octadecane, or icosane. In some embodiments, each long-chain alkyl group can be octadecane. The long-chain alkyl group can be linear or branched, and optionally substituted.
The siloxane polymer can have any suitable number of monomer repeat units. For example, the siloxane polymer can include from 5 to 100 monomer repeat units. Alternatively, the siloxane polymer can include about 5, 10, 15, 20, 25, 30, 40, 50, 60, 70, 80, 90 or 100 monomer repeat units. In some embodiments, the siloxane polymer can include from about 5 to about 50, or about 10 to about 50, or about 10 to about 25 monomer repeat units.
When there are at least two types of monomer repeat units, one type of monomer repeat can be present in a greater amount relative to the other types of monomer repeat units. Alternatively, the different types of monomer repeat units can be present in about the same amount. In some embodiments, the first population of monomer repeat units is about the same number as the second population of monomer repeat units.
Each monomer repeat unit can be the same or different. In some embodiments, there are at least two types of monomer repeat units in the siloxane polymer. In some embodiments, the siloxane polymer includes at least two types of monomer repeat units where a first type includes to the long-chain alkyl group and a second type includes to the alkylamine binding group. Other types of monomer repeat units can also be present. The siloxane polymer of the present invention can include 1, 2, 3, 4 or more different kinds of monomer repeat units. In some embodiments, the siloxane polymers of the present invention have a single type of monomer repeat unit. In other embodiments, the siloxane polymers of the present invention have two different types of monomer repeat units.
In some embodiments, each monomer repeat unit is covalently linked to both the amine or carboxy binding group and the long-chain alkyl group, such that the first and second populations of monomer repeat units are the same.
In some embodiments, each monomer repeat unit is covalently linked to both the alkylamine binding group and the long-chain alkyl group, such that the first and second populations of monomer repeat units are the same.
In some embodiments, the quantum dot binding ligand has the structure of formula I:
wherein each R 1 can independently be C 1-20 alkyl, C 1-20 heteroalkyl, C 2-20 alkenyl, C 2-20 alkynyl, cycloalkyl or aryl, each optionally substituted with one or more —Si(R 1a ) 3 groups; each R 1a can independently be C 1-6 alkyl, cycloalkyl or aryl; each L can independently be C 3-8 alkylene, C 3-8 heteroalkylene, C 3-8 alkylene-O—C 2-8 alkylene, C 3-8 alkylene-(C(O)NH—C 2-8 alkylene) q , C 3-8 heteroalkylene-(C(O)NH—C 2-8 alkylene) q , or C 3-8 alkylene-O—C 1-8 alkylene-(C(O)NH—C 2-8 alkylene) q ; each R 2 can independently be NR 2a R 2b or C(O)OH; each of R 2a and R 2b ) can independently be H or C 1-6 alkyl; each R 3 can independently be C 1-20 alkyl, C 2-20 alkenyl, C 2-20 alkynyl, cycloalkyl or aryl; each R 4 can independently be C 8-20 alkyl, C 8-20 heteroalkyl, cycloalkyl or aryl, each optionally substituted with one or more —Si(R 1a ) 3 groups; each R 5 can independently be C 1-20 alkyl, C 2-20 alkenyl, C 2-20 alkynyl, -L-(R 2 ) q , cycloalkyl or aryl; subscript m is an integer from 5 to 50; subscript n is an integer from 0 to 50; and subscript q is an integer from 1 to 10, wherein when subscript n is 0, then R 1 can be C 8-20 alkyl, C 8-20 heteroalkyl, C 8-20 alkenyl, C 8-20 alkynyl, cycloalkyl or aryl, each optionally substituted with one or more —Si(R 1a ) 3 groups.
In some embodiments, wherein each R 1 can independently be C 1-20 alkyl, C 1-20 heteroalkyl, C 2-20 alkenyl, C 2-20 alkynyl, cycloalkyl or ary; each R 1a can independently be C 1-6 alkyl, cycloalkyl or aryl; each L can independently be C 3-8 alkylene; each R 2 can independently be NR 2a R 2b or C(O)OH; each of R 2a and R 2b can independently be H or C 1-6 alkyl; each R 3 can independently be C 1-20 alkyl, C 2-20 alkenyl, C 2-20 alkynyl, cycloalkyl or aryl; each R 4 can independently be C 8-20 alkyl, C 8-20 heteroalkyl, cycloalkyl or aryl; each R 5 can independently be C 1-20 alkyl, C 2-20 alkenyl, C 2-20 alkynyl, -L-(R 2 ) q , cycloalkyl or aryl; subscript m is an integer from 5 to 50; subscript n is an integer from 0 to 50; and subscript q is an integer from 1 to 10, wherein when subscript n is 0, then R 1 can be C 8-20 alkyl, C 8-20 heteroalkyl, C 8-20 alkenyl, C 8-20 alkynyl, cycloalkyl or aryl.
Radical L can be any suitable linker to link the binding group R 2 to the siloxane polymer. In some embodiments, each L can independently be C 3-8 alkylene, C 3-8 alkylene-O—C 2-8 alkylene, C 3-8 alkylene-(C(O)NH—C 2-8 alkylene) 2 , or C 3-8 alkylene-O—C 1-8 alkylene-(C(O)NH—C 2-8 alkylene) 3 . In other embodiments, each L can independently be C 3-8 alkylene. In some other embodiments, each L can independently be propylene, butylene, pentylene, n-propylene-O-i-propylene, and pentylene-(C(O)NH-ethylene) 2 . In still other embodiments, each L can independent by propylene, butylene or pentylene.
The binding group, R 2 , can be any suitable amine or carboxylic acid. For example, R 2 can be a primary amine where both of R 2a and R 2b are H. Alternatively, R 2 can be a secondary amine where one of R 2a and R 2b is H and the other is C 1-6 alkyl. Representative secondary amines include, but are not limited to, those where R 2a is methyl, ethyl, propyl, isopropyl, butyl, etc. Tertiary amines, where each of R 2a and R 2b is C 1-6 alkyl, are also useful as the binding group R 2 . In those cases, the R 2a and R 2b can be the same or different. Representative tertiary amines include, but are not limited to —N(Me) 2 , —N(Et) 2 , —N(Pr) 2 , —N(Me)(Et), —N(Me)(Pr), —N(Et)(Pr), among others.
In some embodiments, each -L-(R 2 ) q group can independently be C 3-8 alkylene-(R 2 ) 1-3 , C 3-8 heteroalkylene-R 2 , or C 3-8 alkylene-(C(O)NH—C 2-8 alkylene-R 2 ) 2 . In other embodiments, each L-(R 2 ) q group can independently be C 3-8 alkylene-C(O)OH, C 3-8 alkylene-(C(O)OH) 2 , C 3-8 alkylene-O—C 2-8 alkylene-(C(O)OH) 3 , C 3-8 alkylene-NR 2a R 2b , or C 3-8 alkylene-(C(O)NH—C 2-8 alkylene-NR 2a R 2b ) 2 . In some other embodiments, each L-(R 2 ) q group can independently be C 3-8 alkylene-C(O)OH, C 3-8 alkylene-(C(O)OH) 2 , or C 3-8 alkylene-NR 2a R 2b . In some other embodiments, each L-(R 2 ) q group can independently be:
In still other embodiments, each L-(R 2 ) q group can independently be:
One of radicals R 1 and R 4 can be the solubilizing ligand. When subscript n is 0, R 1 can be the solubilizing ligand. When subscript n is greater than 1, either of R 1 and R 4 can be the solubilizing ligand. Any suitable solubilizing ligand can be used in the present invention. In some embodiments, at least one of R 1 and R 4 can be C 8-20 alkyl or C 8-20 heteroalkyl, wherein each alkyl group is optionally substituted with one —Si(R 1a ) 3 group. In other embodiments, at least one of R 1 and R 4 can be C 8-20 alkyl or C 8-20 heteroalkyl. In some other embodiments, at least one of R 1 and R 4 can be C 16 alkyl, C 18 alkyl, C 20 alkyl, or —(CH 2 ) 2 —(OCH 2 CH 2 ) 3 —OCH 3 , wherein each alkyl group is optionally substituted with one —Si(R 1a ) 3 group. In still other embodiments, at least one of R 1 and R 4 can be C 16 alkyl, C 18 alkyl, C 20 alkyl, or —(CH 2 ) 2 —(OCH 2 CH 2 ) 3 —OCH 3 .
When the alkyl group of R 1 or R 4 is substituted with the —Si(R 1a ) 3 group, the substitution can be at any point on the alkyl group, including the terminal carbon, or any other carbon in the alkyl chain. The alkyl group can be branched or unbranched. The R 1a group can be any suitable group that promotes solubilization of the siloxane polymer. For example, each R 1a can independently be C 1-6 alkyl, cycloalkyl or aryl. Each R 1a can be the same or different. In some embodiments, each R 1a can independently be C 1-6 alkyl. The alkyl groups of R 1a can be branched or unbranched. Representative alkyl groups of R 1a include, but are not limited to, methyl, ethyl, propyl, etc. In some embodiments, each R 1a can be ethyl.
Radical R 3 can be any suitable group. In some embodiments, each R 3 can independently be C 1-20 alkyl, C 2-20 alkenyl, C 2-20 alkynyl, cycloalkyl or aryl. In other embodiments, each R 3 can independently be C 1-20 alkyl. In some other embodiments, each R 3 can independently be C 1-6 alkyl. In still other embodiments, each R 3 can independently be C 1-3 alkyl. In yet other embodiments, each R 3 can independently be methyl, ethyl or propyl. In still yet other embodiments, each R 3 can be methyl.
R 5 can be any suitable group. In some embodiments, each R 5 can independently be C 1-20 alkyl, C 2-20 alkenyl, C 2-20 alkynyl, -L-(R 2 ) q , cycloalkyl or aryl. In other embodiments, each R 5 can independently be C 1-20 alkyl. In some other embodiments, each R 5 can independently be C 1-6 alkyl. In still other embodiments, each R 5 can independently be C 1-3 alkyl. In yet other embodiments, each R 5 can independently be methyl, ethyl or propyl. In still yet other embodiments, each R 5 can be methyl.
Alternatively, R 5 can be an amine or carboxy binding group, or a solubilizing group. In some embodiments, at least one R 5 can be -L-(R 2 ) q , as defined above. In other embodiments, at least one R 5 can be C 8-20 alkyl. In some other embodiments, at least one R 5 can be C 12-20 alkyl. In still other embodiments, at least one R 5 can be octadecane.
When the quantum dot binding-ligands of the present invention have two types of monomer repeat units, such that subscript n is not 0, the structure can be the structure of formula I, wherein each R 5 can independently be C 1-20 alkyl, C 2-20 alkenyl, C 2-20 alkynyl, cycloalkyl or aryl; subscript m can be an integer from 5 to 50; and subscript n can be an integer from 1 to 50. In some embodiments, R 1 can independently be C 1-3 alkyl. In some embodiments, the alkyl groups of R 4 can be C 8-20 , C 12-20 , C 14-20 , C 16-20 , or C 18-20 .
Any suitable number of subscripts m and n can be present in the quantum dot binding-ligands of the present invention. For example, the number of subscripts m and n can be from about 1 to about 100, or from about 5 to about 100, or from about 5 to about 50, or from about 10 to about 50, or from about 10 to about 25. Alternatively, the number of subscripts m and n can be about 5, 10, 15, 20, 25, 30, 40, 50, 60, 70, 80, 90 or about 100.
Any suitable ratio of subscripts m and n can be present in the quantum dot binding-ligands of the present invention. For example, the ratio of subscript m to n can be from about 10:1, 5:1, 2.5:1 2:1, 1:1, 1:2, 1:2.5, 1:5 or about 1:10. In some embodiments, the ratio of subscript m to subscript n is about 2:1. In some embodiments, the ratio of subscript m to subscript n is about 1:1. In some embodiments, the ratio of subscript m to subscript n is about 1:2.
In some embodiments, R 1 and R 3 can each independently be C 1-3 alkyl; each R 1a can independently be C 1-6 alkyl; each R 4 can independently be C 8-20 alkyl or C 8-20 heteroalkyl, wherein the alkyl group can optionally be substituted with one —Si(R 1a ) 3 group; each R 5 can independently be C 1-3 alkyl; and subscript q can be an integer from 1 to 3.
In some embodiments, subscript n is other than 0. In other embodiments, the quantum dot binding ligand can have the following structure:
wherein subscripts m and n are each an integer from 10 to 14. In some embodiments, the quantum dot binding ligand can have any of the following structures:
wherein each R 1a can independently be C 1-6 alkyl, and subscripts m and n can each be an integer from 10 to 14.
In some embodiments, the quantum dot binding ligand can have any of the following structures:
wherein each R 1a can independently be C 1-6 alkyl, and subscripts m and n can each be an integer from 10 to 14.
In some embodiments, subscript n is 0. In other embodiments, each R 5 can independently be C 1-20 alkyl, C 2-20 alkenyl, C 2-20 alkynyl, cycloalkyl or aryl; subscript m can be an integer from 5 to 50; and subscript n can be 0. In some other embodiments, each R 1 can independently be C 8-20 alkyl or C 8-20 heteroalkyl, wherein the alkyl group can optionally be substituted with one —Si(R 1a ) 3 group; each R 1a can independently be C 1-6 alkyl; each R 5 can independently be C 1-3 alkyl; and subscript q can be an integer from 1 to 3. In still other embodiments, each R 1 can independently be C 8-20 alkyl or C 8-20 heteroalkyl; each R 1a can independently be C 1-6 alkyl; each R 5 can independently be C 1-3 alkyl; and subscript q can be an integer from 1 to 3.
In some embodiments, the quantum dot binding ligand has the structure:
In other embodiments, R 1 can be C 8-20 alkyl. In some other embodiments, the quantum dot binding ligand can have any of the following structures:
wherein subscript m is an integer from 5 to 50.
In other embodiments, R 1 can be C 8-20 alkyl. In some other embodiments, the quantum dot binding ligand can have any of the following structures:
wherein subscript m is an integer from 5 to 50.
In some embodiments, the quantum dot binding ligand has the structure of formula Ia:
wherein each R 1 can independently be C 1-20 alkyl, C 2-20 alkenyl, C 2-20 alkynyl, cycloalkyl or ary, wherein the alkyl group is optionally substituted with one —Si(R 1a ) 3 group 1; each R 2 can independently be C 3-8 alkyl-NR 2a R 2b ; each of R 2a and R 2b can independently be H or C 1-6 alkyl; each R 3 can independently be C 1-20 alkyl, C 2-20 alkenyl, C 2-20 alkynyl, cycloalkyl or aryl; each R 4 can independently be C 8-20 alkyl; each R 5 can independently be C 1-20 alkyl, C 2-20 alkenyl, C 2-20 alkynyl, C 3-8 alkyl-NR 2a R 2b , cycloalkyl or aryl; subscript m can be an integer from 5 to 50; and subscript n can be an integer from 0 to 50; wherein when subscript n is 0, then R 1 can be C 8-20 alkyl, C 8-20 alkenyl, C 8-20 alkynyl, cycloalkyl or aryl. In some embodiments, the alkyl groups of R 1 or R 4 can be C 8-20 , C 12-20 , C 14-20 , C 16-20 , or C 18-20 .
Radical R 5 can be any suitable group. In some embodiments, each R 5 can independently be C 1-20 alkyl, C 2-20 alkenyl, C 2-20 alkynyl, C 3-8 alkyl-NR 2a R 2b , cycloalkyl or aryl. In some embodiments, each R 5 can independently be C 1-20 alkyl, C 2-20 alkenyl, C 2-20 alkynyl, cycloalkyl or aryl. In some embodiments, each R 5 can be C 1-20 alkyl. In some embodiments, each R 5 can be C 8-20 alkyl. In some embodiments, each R 5 can be octadecane. In some embodiments, each R 5 can be C 1-3 alkyl. In some embodiments, each R 5 can independently be methyl, ethyl or propyl. In some embodiments, each R 5 can be aryl. In some embodiments, each R 5 can be phenyl. In some embodiments, R 5 can be C 3-8 alkyl-NR 2a R 2b . In some embodiments, R 5 can be C 3 alkyl-NR 2a R 2b . In some embodiments, each R 5 can independently be octadecane or C 3 alkyl-NR 2a R 2b .
In some embodiments, the quantum dot binding-ligand can have the following structure:
In some embodiments, the quantum dot binding-ligand of the present invention has the following structure:
wherein subscripts m and n are each an integer from 10 to 14.
When the quantum dot binding-ligands of the present invention have a single type of monomer repeat unit, such that subscript n is 0, the structure can be the structure of formula I, wherein each R 1 can independently be C 8-20 alkyl, C 8-20 alkenyl, C 8-20 alkynyl, cycloalkyl or aryl. In some embodiments, each R 1 can independently be C 8-20 alkyl; subscript m can be an integer from 5 to 50; and subscript n can be 0. In some embodiments, the quantum dot binding-ligand of formula I can have the following structure:
In some embodiments, the quantum dot binding-ligand of formula I can have the following structure:
wherein R 1 can be C 8-20 alkyl; and subscript p can be an integer from 1 to 6. In some embodiments, subscript p can be 1, 2, 3, 4, 5, or 6. In some embodiments, subscript p can be 1.
In some embodiments, the quantum dot binding-ligand of formula I can have the following structure:
wherein subscript m can an integer from 6 to 8.
In some embodiments, each R 5 can independently be C 8-20 alkyl, C 8-20 alkenyl, C 8-20 alkynyl, C 3-8 alkyl-NR 2a R 2b , cycloalkyl or aryl. In some embodiments, each R 5 can independently be C 8-20 alkyl or C 3-8 alkyl-NR 2a R 2b . In some embodiments, the quantum dot binding-ligand can have the structure:
IV. Methods of Making Quantum Dot Binding-Ligands
The quantum dot binding-ligands of the present invention can be prepared by any suitable means known to one of skill in the art. For example, a commercially available siloxane polymer can be hydrosilylated with an alkene and an alkene-amino in sequential steps (as shown in FIG. 1 ) to form the quantum dot binding-ligand of formula I where subscript n is not 0. Alternatively, a siloxane polymer can be prepared by condensation of a long-chain alkyl functionalized dichlorosilane (RSi(Cl) 2 H) with water, followed by end-capping the terminal chloro groups of the polymer, and then hydrosilylation of the silane groups with a suitable alkeneamine ( FIG. 2 ). FIG. 3 shows yet another method for preparing the quantum dot binding-ligands of the present invention. Following the method described in FIG. 2 , any bis-substituted chlorosilane (1a) prepared in the first step is separated, converted to a silanol (1b), and then reacted with the siloxane polymer (2) to form the end-capped siloxane polymer (3a). The remaining silane groups are reacted with a suitable alkene and Karstedt's catalyst to prepare the final product (4a), having two additional alkyl-amine groups and four additional long-chain alkyl groups compared to the product of the scheme in FIG. 2 . Other methods of making the quantum dot binding ligands of the present invention are described in the remaining figures.
In some embodiments, the present invention provides a method of making a quantum dot binding-ligand of formula Ib:
The method of making the quantum dot binding-ligand of formula I includes forming a reaction mixture having water and a compound of formula II:
to afford a compound of formula III:
The method also includes forming a reaction mixture of (R 5 ) 3 SiOM and the compound of formula III, to afford a compound of formula IV:
The method also includes forming a reaction mixture of the compound of formula IV, a catalyst, and CH 2 ═CH(CH 2 ) p NR 2a R 2b , thereby forming the compound of formula I. For formulas Ib, II, III and IV, each R 1 can independently be C 8-20 alkyl, C 8-20 alkenyl, C 8-20 alkynyl, cycloalkyl or aryl; each of R 2a and R 2b can independently be H or C 1-6 alkyl; each R 5 can independently be C 1-20 alkyl, C 2-20 alkenyl, C 2-20 alkynyl, C 3-8 alkyl-NR 2a R 2b , cycloalkyl or aryl; subscript m can be an integer from 5 to 50; M can be hydrogen or a cation; and subscript p can be an integer of from 1 to 6.
In some embodiments, the alkyl group of R 1 can be C 12-20 , C 14-20 , C 16-20 , or C 18-20 . In some embodiments, the alkyl group of R 1 can be C 18 , octadecane.
Any suitable amount of water is useful in the methods of the present invention. For example, water can be present in an amount from about 0.01 to about 1.0 molar equivalents, or from about 0.1 to less than 1.0 equivalents, or from about 0.25 to about 0.75 equivalents, or from about 0.5 to about 0.75 equivalents. Water can also be present in an amount of about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or about 1.0 molar equivalents. In some embodiments, the water can be present in step (a) in an amount of less than about 1.0 eq. to the compound of formula II. In some embodiments, the water can be present in step (a) in an amount of from about 0.1 to about 0.75 eq. to the compound of formula II. In some embodiments, the water can be present in step (a) in an amount of from about 0.5 to about 0.75 eq. to the compound of formula II.
Any suitable nucleophile can be used to end-cap the terminal chloro groups of formula III. In some embodiments, the nucleophile can be (R 5 ) 3 SiOM, where each R 5 is as described above and M can be hydrogen or a cation. Any suitable cation is useful for the nucleophile, including metal and non-metal cations. In some embodiments, M can be a metal cation such as Na + or K + .
The catalyst of step (b) can be any catalyst suitable for performing a hydrosilylation reaction. For example, the catalyst can be a transition metal catalyst such as Karstedt's catalyst, a platinum based catalyst. In some embodiments, the catalyst can be Karstedt's catalyst.
V. Compositions
The quantum dot binding-ligands of the present invention can be complexed to a quantum dot (QD). In some embodiments, the present invention provides a composition of a quantum dot binding-ligand of the present invention, and a first population of light emitting quantum dots (QDs).
In some embodiments, the quantum dot binding-ligand can have the structure of formula I, as described above. In some embodiments, the quantum dot binding-ligand can have the structure:
wherein subscripts m and n are each an integer from 10 to 14. In some embodiments, the quantum dot binding-ligand can have the structure of formula Ib, as described above. In some embodiments, the quantum dot binding-ligand can have the structure:
wherein subscript m is an integer from 6 to 8.
Quantum Dots
Typically, the region of characteristic dimension will be along the smallest axis of the structure. The QDs can be substantially homogenous in material properties, or in certain embodiments, can be heterogeneous. The optical properties of QDs can be determined by their particle size, chemical or surface composition; and/or by suitable optical testing available in the art. The ability to tailor the nanocrystal size in the range between about 1 nm and about 15 nm enables photoemission coverage in the entire optical spectrum to offer great versatility in color rendering. Particle encapsulation offers robustness against chemical and UV deteriorating agents.
Additional exemplary nanostructures include, but are not limited to, nanowires, nanorods, nanotubes, branched nanostructures, nanotetrapods, tripods, bipods, nanoparticles, and similar structures having at least one region or characteristic dimension (optionally each of the three dimensions) with a dimension of less than about 500 nm, e.g., less than about 200 nm, less than about 100 nm, less than about 50 nm, or even less than about 20 nm or less than about 10 nm. Typically, the region or characteristic dimension will be along the smallest axis of the structure. Nanostructures can be, e.g., substantially crystalline, substantially monocrystalline, polycrystalline, amorphous, or a combination thereof.
QDs (or other nanostructures) for use in the present invention can be produced using any method known to those skilled in the art. For example, suitable QDs and methods for forming suitable QDs include those disclosed in: U.S. Pat. No. 6,225,198, U.S. Pat. No. 6,207,229, U.S. Pat. No. 6,322,901, U.S. Pat. No. 6,872,249, U.S. Pat. No. 6,949,206, U.S. Pat. No. 7,572,393, U.S. Pat. No. 7,267,865, U.S. Pat. No. 7,374,807, US Patent Publication No. 2008/0118755, filed Dec. 9, 2005, and U.S. Pat. No. 6,861,155, each of which is incorporated by reference herein in its entirety.
The QDs (or other nanostructures) for use in the present invention can be produced from any suitable material, suitably an inorganic material, and more suitably an inorganic conductive or semiconductive material. Suitable semiconductor materials include any type of semiconductor, including group II-VI, group III-V, group IV-VI and group IV semiconductors. Suitable semiconductor materials include, but are not limited to, Si, Ge, Sn, Se, Te, B, C (including diamond), P, BN, BP, BAs, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, ZnO, ZnS, ZnSe, ZnTe, CdS, CdSe, CdSeZn, CdTe, HgS, HgSe, HgTe, BeS, BeSe, BeTe, MgS, MgSe, GeS, GeSe, GeTe, SnS, SnSe, SnTe, PbO, PbS, PbSe, PbTe, CuF, CuCl, CuBr, CuI, Si 3 N 4 , Ge 3 N 4 , Al 2 O 3 , (Al, Ga, In) 2 (S, Se, Te) 3 , Al 2 CO 3 , and appropriate combinations of two or more such semiconductors.
In some embodiments, the semiconductor nanocrystals or other nanostructures can also include a dopant, such as a p-type dopant or an n-type dopant. The nanocrystals (or other nanostructures) useful in the present invention can also include II-VI or III-V semiconductors. Examples of II-VI or III-V semiconductor nanocrystals and nanostructures include any combination of an element from Group II, such as Zn, Cd and Hg, with any element from Group VI, such as S, Se, Te, Po, of the Periodic Table; and any combination of an element from Group III, such as B, Al, Ga, In, and Tl, with any element from Group V, such as N, P, As, Sb and Bi, of the Periodic Table. Other suitable inorganic nanostructures include metal nanostructures. Suitable metals include, but are not limited to, Ru, Pd, Pt, Ni, W, Ta, Co, Mo, Ir, Re, Rh, Hf, Nb, Au, Ag, Ti, Sn, Zn, Fe, FePt, and the like.
While any method known to the ordinarily skilled artisan can be used to create nanocrystal phosphors, suitably, a solution-phase colloidal method for controlled growth of inorganic nanomaterial phosphors is used. See Alivisatos, A. P., “Semiconductor clusters, nanocrystals, and quantum dots,” Science 271:933 (1996); X. Peng, M. Schlamp, A. Kadavanich, A. P. Alivisatos, “Epitaxial growth of highly luminescent CdSe/CdS Core/Shell nanocrystals with photostability and electronic accessibility,” J. Am. Chem. Soc. 30:7019-7029 (1997); and C. B. Murray, D. J. Norris, M. G. Bawendi, “Synthesis and characterization of nearly monodisperse CdE (E=sulfur, selenium, tellurium) semiconductor nanocrystallites,” J. Am. Chem. Soc. 115:8706 (1993), the disclosures of which are incorporated by reference herein in their entireties. This manufacturing process technology leverages low cost processability without the need for clean rooms and expensive manufacturing equipment. In these methods, metal precursors that undergo pyrolysis at high temperature are rapidly injected into a hot solution of organic surfactant molecules. These precursors break apart at elevated temperatures and react to nucleate nanocrystals. After this initial nucleation phase, a growth phase begins by the addition of monomers to the growing crystal. The result is freestanding crystalline nanoparticles in solution that have an organic surfactant molecule coating their surface.
Utilizing this approach, synthesis occurs as an initial nucleation event that takes place over seconds, followed by crystal growth at elevated temperature for several minutes. Parameters such as the temperature, types of surfactants present, precursor materials, and ratios of surfactants to monomers can be modified so as to change the nature and progress of the reaction. The temperature controls the structural phase of the nucleation event, rate of decomposition of precursors, and rate of growth. The organic surfactant molecules mediate both solubility and control of the nanocrystal shape. The ratio of surfactants to monomer, surfactants to each other, monomers to each other, and the individual concentrations of monomers strongly influence the kinetics of growth.
In semiconductor nanocrystals, photo-induced emission arises from the band edge states of the nanocrystal. The band-edge emission from luminescent nanocrystals competes with radiative and non-radiative decay channels originating from surface electronic states. X. Peng, et al., J. Am. Chem. Soc. 30:7019-7029 (1997). As a result, the presence of surface defects such as dangling bonds provide non-radiative recombination centers and contribute to lowered emission efficiency. An efficient and permanent method to passivate and remove the surface trap states is to epitaxially grow an inorganic shell material on the surface of the nanocrystal. X. Peng, et al., J. Am. Chem. Soc. 30:7019-7029 (1997). The shell material can be chosen such that the electronic levels are type I with respect to the core material (e.g., with a larger bandgap to provide a potential step localizing the electron and hole to the core). As a result, the probability of non-radiative recombination can be reduced.
Core-shell structures are obtained by adding organometallic precursors containing the shell materials to a reaction mixture containing the core nanocrystal. In this case, rather than a nucleation-event followed by growth, the cores act as the nuclei, and the shells grow from their surface. The temperature of the reaction is kept low to favor the addition of shell material monomers to the core surface, while preventing independent nucleation of nanocrystals of the shell materials. Surfactants in the reaction mixture are present to direct the controlled growth of shell material and ensure solubility. A uniform and epitaxially grown shell is obtained when there is a low lattice mismatch between the two materials.
Exemplary materials for preparing core-shell luminescent nanocrystals include, but are not limited to, Si, Ge, Sn, Se, Te, B, C (including diamond), P, Co, Au, BN, BP, BAs, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, ZnO, ZnS, ZnSe, ZnTe, CdS, CdSe, CdSeZn, CdTe, HgS, HgSe, HgTe, BeS, BeSe, BeTe, MgS, MgSe, GeS, GeSe, GeTe, SnS, SnSe, SnTe, PbO, PbS, PbSe, PbTe, CuF, CuCl, CuBr, CuI, Si 3 N 4 , Ge 3 N 4 , Al 2 O 3 , (Al, Ga, In) 2 (S, Se, Te) 3 , Al 2 CO 3 , and appropriate combinations of two or more such materials. Exemplary core-shell luminescent nanocrystals for use in the practice of the present invention include, but are not limited to, (represented as Core/Shell), CdSe/ZnS, InP/ZnS, PbSe/PbS, CdSe/CdS, CdTe/CdS, CdTe/ZnS, as well as others.
In some embodiments, CdSe is used as the nanocrystal material, due to the relative maturity of the synthesis of this material. Due to the use of a generic surface chemistry, it is also possible to substitute non-cadmium-containing nanocrystals. Exemplary luminescent nanocrystal materials include CdSe or ZnS, including core/shell luminescent nanocrystals comprising CdSe/CdS/ZnS, CdSe/ZnS, CdSeZn/CdS/ZnS, CdSeZn/ZnS, InP/ZnS, PbSe/PbS, CdSe/CdS, CdTe/CdS or CdTe/ZnS. Most preferably, the quantum dots of the present invention can include core-shell QDs having a core including CdSe and at least one encapsulating shell layer including CdS or ZnS. In other embodiments, InP is used as the nanocrystal material.
In some embodiments, the light emitting quantum dots can be CdSe or CdTe and quantum-dot binding ligand can include an amine binding group. In other embodiments, the light emitting quantum dots can be CdSe or CdTe and R 2 can be NR 2a R 2b . In some other embodiments, the light emitting quantum dots can be InP and quantum-dot binding ligand can include a carboxy binding group. In still other embodiments, the light emitting quantum dots can be InP and R 2 can be C(O)OH.
The luminescent nanocrystals can be made from a material impervious to oxygen, thereby simplifying oxygen barrier requirements and photostabilization of the QDs in the QD phosphor material. In some embodiments, the luminescent nanocrystals can be coated with one or more quantum dot binding-ligand of the present invention and dispersed in an organic polymeric matrix having one or more matrix materials, as discussed in more detail below. The luminescent nanocrystals can be further coated with one or more inorganic layers having one or more material such as a silicon oxide, an aluminum oxide, or a titanium oxide (e.g., SiO 2 , Si 2 O 3 , TiO 2 , or Al 2 O 3 ), to hermetically seal the QDs.
Matrix Materials
Generally, the polymeric ligand is bound to a surface of the nanostructure. Not all of the ligand material in the composition need be bound to the nanostructure, however. The polymeric ligand can be provided in excess, such that some molecules of the ligand are bound to a surface of the nanostructure and other molecules of the ligand are not bound to the surface of the nanostructure.
The phosphor material of the present invention further comprises a matrix material in which the QDs are embedded or otherwise disposed. The matrix material can be any suitable host matrix material capable of housing the QDs. Suitable matrix materials will be chemically and optically compatible with back-lighting unit (BLU) components, including the QDs and any surrounding packaging materials or layers. Suitable matrix materials include non-yellowing optical materials which are transparent to both the primary and secondary light, thereby allowing for both primary and secondary light to transmit through the matrix material. In preferred embodiments, the matrix material completely surrounds the QDs and provides a protective barrier which prevents deterioration of the QDs caused by environmental conditions such as oxygen, moisture, and temperature. The matrix material can be flexible in applications where a flexible or moldable QD film is desired. Alternatively, the matrix material can include a high-strength, non-flexible material.
Preferred matrix materials will have low oxygen and moisture permeability, exhibit high photo- and chemical-stability, exhibit favorable refractive indices, and adhere to the barrier or other layers adjacent the QD phosphor material, thus providing an air-tight seal to protect the QDs. Preferred matrix materials will be curable with UV or thermal curing methods to facilitate roll-to-roll processing. Thermal curing is most preferred.
Suitable matrix materials for use in QD phosphor material of the present invention include polymers and organic and inorganic oxides. Suitable polymers for use in the matrixes of the present invention include any polymer known to the ordinarily skilled artisan that can be used for such a purpose. In suitable embodiments, the polymer will be substantially translucent or substantially transparent. Suitable matrix materials include, but are not limited to, epoxies, acrylates, norbornene, polyethylene, poly(vinyl butyral):poly(vinyl acetate), polyurea, polyurethanes; silicones and silicone derivatives including, but not limited to, amino silicone (AMS), polyphenylmethylsiloxane, polyphenylalkylsiloxane, polydiphenylsiloxane, polydialkylsiloxane, silsesquioxanes, fluorinated silicones, and vinyl and hydride substituted silicones; acrylic polymers and copolymers formed from monomers including, but not limited to, methylmethacrylate, butylmethacrylate, and laurylmethacrylate; styrene-based polymers such as polystyrene, amino polystyrene (APS), and poly(acrylonitrile ethylene styrene) (AES); polymers that are crosslinked with bifunctional monomers, such as divinylbenzene; cross-linkers suitable for cross-linking ligand materials, epoxides which combine with ligand amines (e.g., APS or PEI ligand amines) to form epoxy, and the like.
The QDs used the present invention can be embedded in a polymeric matrix (or other matrix material) using any suitable method, for example, mixing the nanocrystals in a polymer and casting a film, mixing the nanocrystals with monomers and polymerizing them together, mixing the nanocrystals in a sol-gel to form an oxide, or any other method known to those skilled in the art. As used herein, the term “embedded” is used to indicate that the luminescent nanocrystals are enclosed or encased within the polymer that makes up the majority component of the matrix. It should be noted that luminescent nanocrystals are suitably uniformly distributed throughout the matrix, though in further embodiments they can be distributed according to an application-specific uniformity distribution function.
The composition optionally includes a plurality or population of the nanostructures, e.g., with bound ligand. The composition optionally includes a solvent, in which the nanostructure(s) and ligand can be dispersed. As noted, the nanostructures and ligand can be incorporated into a matrix to form a polymer layer or nanocomposite (e.g., a silicone matrix formed from the ligand). Thus, the composition can also include a crosslinker and/or an initiator. Suitable crosslinkers include organic or polymeric compounds with two or more functional groups (e.g., two, three, or four) that can react with amine groups (or other groups on the ligand) to form covalent bonds. Such functional groups include, but are not limited to, isocyanate, epoxide (also called epoxy), succinic anhydride or other anhydride or acid anhydride, and methyl ester groups, e.g., on a silicone, hydrocarbon, or other molecule. In one class of embodiments, the crosslinker is an epoxy crosslinker, e.g., an epoxycyclohexyl or epoxypropyl crosslinker (e.g., compounds A-C or D-G in Table 1, respectively). The reactive groups on the crosslinker can be pendant and/or terminal (e.g., compounds B and D or compounds A, C, and E-G in Table 1, respectively). The crosslinker is optionally an epoxy silicone crosslinker, which can be, e.g., linear or branched. In certain embodiments, the crosslinker is a linear epoxycyclohexyl silicone or a linear epoxypropyl (glycidyl) silicone. A number of exemplary crosslinkers are listed in Table 1. Suitable crosslinkers are commercially available. For example, compounds H-K are available from Aldrich and compounds A-G are available from Gelest, Inc., e.g., with a formula weight of about 900-1100 for compound A as product no. DMS-EC13, with a formula weight of about 18,000 and a molar percentage of 3-4% for m for compound B as product no. ECMS-327, with a formula weight of about 8000, m≈6, and n≈100 for compound D as product no. EMS-622, and as product no. DMS-E09 for compound E.
TABLE 1
Exemplary crosslinkers.
A
where n is a positive integer
B
where m and n are positive integers
C
D
where m and n are positive integers (e.g., m ≈ 6 and n ≈ 100)
E
F
where Ph represents a phenyl group
G
where Ph represents a phenyl group
H
1,4-butanediol diglycidyl ether
I
trimethylolpropane triglycidyl ether
J
4,4′-methylenebis(N,N-diglycidylaniline)
K
bisphenol A diglycidyl ether
L
M
1,6-diisocyanate
N
where n is a positive integer
O
where n is a positive integer and where Me represents a methyl group
The quantum dot compositions and films prepared using the quantum dot binding-ligands of the present invention are useful in a variety of light emitting devices, quantum dot lighting devices and quantum dot-based backlighting units. Representative devices are well known to those of skill in the art and can be found, for example, in US Publication Nos. 2010/0167011 and 2012/0113672, and U.S. Pat. Nos. 7,750,235 and 8,053,972.
The quantum dot compositions of the present invention can be used to form a lighting device such as a backlighting unit (BLU). A typical BLU can include a QD film sandwiched between two barrier layers. QD films of the present invention can include a single quantum dot and a single quantum-dot binding-ligand, or a plurality of quantum dots and a plurality of quantum-dot binding-ligands. For example, a QD film of the present invention can include a cadmium quantum dot, such as CdS, CdTe, CdSe, CdSe/CdS, CdTe/CdS, CdTe/ZnS, CdSe/CdS/ZnS, CdSe/ZnS, CdSeZn/CdS/ZnS, or CdSeZn/ZnS, and a quantum-dot binding ligand having amine binding groups. The QD films of the present invention can include an InP quantum dot, such as InP or InP/ZnS, and a quantum-dot binding ligand having carboxy binding groups.
In some embodiments, the QD films of the present invention include both cadmium and indium containing quantum dots. When both cadmium and indium containing quantum dots are present, the QD film can include a first film containing the cadmium quantum dots and a second film containing the indium quantum dots. These films can then be stacked one on top of another to form a layered film. In some embodiments, a barrier film or other type of film can be stacked in between each of the cadmium and indium films. In other embodiments, the cadmium and indium quantum dots are mixed together in a single QD film with their respective quantum-dot binding-ligands.
Mixed QD films, with either a single layer or multi-layer film, have the advantage of reducing the amount of cadmium in the system. For example, the cadmium can be reduced below 300 ppm, 200, 100, 75, 50 or 25 ppm. In some embodiments, the QD film contains less than about 100 ppm cadmium. In other embodiments, the QD film contains less than about 50 ppm.
VI. Examples
General Methods
All manipulations were performed under a dry, oxygen-free, nitrogen atmosphere using standard Schlenk technique. Allylamine, 1-octadecene, polysilane (1) and Karstedt's Catalyst were handled inside the glove box. Dry toluene, allylamine (98%) and 1-octadecene (>95% by GC) were obtained from Sigma-Aldrich. Allylamine was distilled from CaCl 2 and stored under nitrogen before use while 1-octadecene was used without further purification. Karstedt's catalyst, 2.1 to 2.4 wt % in xylenes was obtained from Gelest and used without further purification. A 100× dilution of Karstedt's catalyst was produced by dissolving 0.10 mL of stock solution into 10 mL of toluene. (The stock solution contains 0.113 moles of platinum per mL and the 100× dilution contains 0.00113 mmoles platinum per mL solution.) The polysilane (1) or “polyMethylHydrosiloxanes, Trimethylsilyl terminated” with Mw of 1400-1800 and viscosity 15-29 Cs (PN: HMS-991) was also obtained from Gelest. The silane was purified by vacuum overnight to P<50 mtorr and then handled inside the glove box. NMR chemical shift data were recorded with a Bruker FT NMR at 400 MHz for proton or 100 MHz for 13 C { 1 H} and are listed in ppm. IR analysis was obtained on a Nicolet 7200 FTIR equipped with an attenuated total reflectance (ATR) sampling accessory.
Water will react in the second step of the synthesis with primary amine (amine is 4× equivalents to silane in this step) to produce hydroxide ions and quaternary amine. Then at reaction temperature, hydroxide ions will catalyze re-distribution of the silicone backbone and cause the Mn (number average molecular weight) of the polymer to increase substantially. A little water will cause the Mn to increase slightly while a lot of water will cause the reaction solution to gel. Even a little Mn increase could reduce the ability of the ligand to bind nanocrystals and less efficient nanocrystal binding will reduce the stability nanocrystal/ligand complex.
Example 1
Preparation of Polymeric Silicone Amine Wax (PSAW-1:1)
This example provides a method for making polymeric silicone amine wax (PSAW) with a 1:1 ratio of alkyl amine (aminopropyl) to long-chain alkyl (octadecyl).
The apparatus was set up with a 250 mL, 3-neck RBF equipped with nitrogen inlet adapter (Teflon valve/stopper), thermocouple positioned to measure reaction solution temperature directly (with temperature controller) and short path distillation head with receiver. Additionally the distillation head was attached to a bubbler containing a one-way valve. The apparatus was configured so that upon attachment of a Schlenk line to the hose adapter, nitrogen gas could be passed into the reaction flask, across the surface of the reaction solution and out the bubbler attached to the distillation head. Also, the one way valve on the bubbler allowed vacuum to be applied to the whole apparatus, from the bubbler to the hose adapter.
After attachment to the Schlenk line, silane polymer HMS-991 (10 g, 10.2 mL, 6.25 mmoles of polymer strands with 150 mmoles of silane) was added followed by 1-octadecene (18.9 g, 24.0 mL, 75 mmoles) by syringe. The reaction apparatus was placed under vacuum until a pressure of less than 100 mtorr was reached and back flushed with nitrogen 3 times. Vacuum was applied with the valve between the distillation head and bubbler open. Then toluene (50 mL) was added, nitrogen gas flow was adjusted to slowly pass through the apparatus and out the bubbler. Also coolant was circulated through the distillation head condenser and the reaction solution temperature was set to 120 C. Distillation was continued until about half the toluene was collected or about 25 mL. Then the reaction solution was cooled to 60 C and the distillation head was replaced by a nitrogen filled reflux condenser connected to the Schlenk line. The reaction solution was heated to 100 C and Karstedt's catalyst (3.32 mL of a 100× dilution of stock solution with 0.731 mg and 0.00375 mmoles platinum or enough for 20,000 turnovers) was added by syringe. Then the reaction solution was heated at 100 C with stirring overnight. After heating the slightly amber reaction solution was sampled and the volatiles removed for NMR and IR analysis. Analysis by proton NMR indicated that the olefin had been consumed and the silane peak had been reduced in size by 50%. The next step in the synthesis was performed without isolation of intermediate 2. However, polysilane silicone wax 2 was isolated and characterized. 1 H NMR (toluene-d 8 , δ): 0.1 to 0.4 (broad m, 90H, SiCH 3 ), 0.7 to 1.0 (broad m, 60H, SiCH 2 (CH 2 ) 16 CH 3 ), 1.2 to 1.7 (broad m, 192H, SiCH 2 (CH 2 ) 16 CH 3 ), 5.0 to 5.2 (broad m, 12H, SiH). IR (cm −1 , diamond): 2957 sh, 2917 s, 2850 s (sp 3 C—H), 2168 sh, 2158 m (Si—H), 1466 (sp 3 C—H), 1258 s (Si—CH 3 ), 1086 sh, 1033 s (Si—O—Si) and 765 s (Si—CH 3 ).
Analysis of Starting Material Polysilane Silicone (Gelest PN:HMS-991) (1):
1 H NMR (neat with coaxial insert using benzene-d 6 , δ): 0.72 to 0.96 (m, 90H, CH 3 ), 5.40 (s, 24H, silane). 13 C { 1 H} (neat with coaxial insert using benzene-d 6 , δ): 1.6 to 2.7 (m, CH 3 ). IR (cm −1 , diamond): 2966 w (sp 3 C—H), 2160 m (Si—H), 1259 m (sp 3 C—H), 1034 s (Si—O—Si), 833 s (Si—H) and 752 s (Si—CH 3 ).
The reaction solution was then cooled to 60 C and allylamine (17.1 g, 22.5 mL, 300 mmoles) was added by syringe which instantly produced a colorless solution. Immediately following allylamine, Karstedt's catalyst (0.66 mL, 14.6 mg and 0.075 mmoles of platinum or enough for 1000 turnovers) was added by syringe. The reaction solution temperature was then set to 80 C and the solution heated for 2 h. A sample was prepared for analysis by vacuum transfer of volatiles. Proton NMR indicated a significant reduction of the Si—H peak with lumpy resonances integrating to about 0.25 of the analysis of intermediate 2. Therefore, since other peaks obscure integration in the Si—H region, FTIR analysis was used to provide an accurate determination. FTIR determined almost complete disappearance of the Si—H peak.
Following consumption of the silane, the reaction solution was cooled to room temperature for removal of volatiles by vacuum transfer. For this step the reflux condenser and thermocouple were replaced by stoppers and the reaction flask connected to a supplemental trap cooled by dry ice/ethanol. The product was dried on that vacuum system for a couple of hours then the solids were broken by spatula before drying under vacuum at room temperature overnight. In the morning the product was divided up further with a spatula and the reaction flask was placed directly on the Schlenk line until a pressure of <50 mtorr was reached for 30 minutes. The product PSAW-1:1, a waxy semi-crystalline white solid (27.9 g, 5.26 mmoles or 84.2% yield) was stored in the glove box. 1 H NMR (toluene-d 8 , δ): 0.2 to 0.5 (broad m, 90H, SiCH 3 ), 0.6 to 1.0 (broad m, 84H, SiCH 2 CH 2 CH 2 NH 2 , SiCH 2 (CH 2 ) 16 CH 3 ), 1.2 to 1.7 (broad m, 216H, SiCH 2 CH 2 CH 2 NH 2 , SiCH 2 (CH 2 ) 16 CH 3 ), 2.5 to 2.8 (broad m, 24H, SiCH 2 CH 2 CH 2 NH 2 ) 3.4 to 3.6 (broad m, 24H, SiCH 2 CH 2 CH 2 NH 2 ). IR (cm −1 , diamond): 2958 sh, 2916 s, 2849 s (sp 3 C—H), 1467 w (sp 3 C—H), 1257 m (Si—CH 3 ), 1074 sh, 1015 (Si—O—Si) and 784 sh, 767 s (Si—CH 3 ).
Determination of Ratio of Alkyl Amine to Long-Chain Alkyl.
The amine to C18 ratio was determined by the stoichiometry of the two sequential reactions in the synthesis. For example in PSAW-1:1, the first hydroslation with 1-octadecene was driven to completion. The stoichiometry (i.e. 1-octadecene added) determined that half the siloxy repeat units (or initial Si—H bonds) are attached to octadecenyl groups. Even though the second hydrosilation uses 4 times the amount of allylamine compared to the number of Si—H bonds that remain, only one quarter that amounts reacts with the polymer leaving three quarters in the reaction solution. Once the remaining Si—H bonds were reacted with allylamine, the left-over allylamine was removed by precipitation into methanol. The excess allylamine is soluble in methanol and was washed away from the product in the work up.
Example 2
Preparation of Polymeric Silicone Amine Wax (PSAW-1:2)
This example provides a method for making polymeric silicone amine wax (PSAW) with a 1:2 ratio of alkyl amine (aminopropyl) to long-chain alkyl (octadecyl), using the procedure described above in Example 1. For example, silane polymer HMS-991 (10 g, 10.2 mL, 6.25 mmoles of polymer strands with 150 mmoles of silane) used 1-octadecene (25.3 g, 32.0 mL, 100 mmoles) and allylamine (11.4 g, 15.0 mL, 200 mmoles). Karstedt's catalyst was also scaled accordingly, using platinum for 20,000 turnovers in the first step (0.0050 mmoles) and then 1000 turnovers in the second step (0.050 mmoles). (302-071)
Analysis of Polymeric Silicone Amine Wax PSAW-1:2.
1 H NMR (toluene-d 8 , δ): 0.2 to 0.5 (broad m, 90H, SiCH 3 ), 0.6 to 1.0 (broad m, 96H, SiCH 2 CH 2 CH 2 NH 2 , SiCH 2 (CH 2 ) 16 CH 3 ), 1.1 to 1.7 (broad m, 528H, SiCH 2 CH 2 CH 2 NH 2 , SiCH 2 (CH 2 ) 16 CH 3 ), 2.5 to 2.8 (broad m, 16H, SiCH 2 CH 2 CH 2 NH 2 ) 3.4 to 3.7 (broad m, 16H, SiCH 2 CH 2 CH 2 NH 2 ). IR (cm −1 , diamond): 2958 sh, 2916 s, 2849 s (sp 3 C—H), 1467 w (sp 3 C—H), 1257 m (Si—CH 3 ), 1074 sh, 1015 (Si—O—Si) and 784 sh, 767 s (Si—CH 3 ).
Example 3
Preparation of Polymeric Silicone Amine Wax (PSAW-2:1)
This example provides a method for making polymeric silicone amine wax (PSAW) with a 2:1 ratio of alkyl amine (aminopropyl) to long-chain alkyl (octadecyl), using the procedure described above in Example 1. For example, silane polymer HMS-991 (10 g, 10.2 mL, 6.25 mmoles of polymer strands with 150 mmoles of silane) used 1-octadecene (12.6 g, 16.0 mL, 50 mmoles) and allylamine (22.8 g, 30.0 mL, 400 mmoles). Karstedt's catalyst was also scaled accordingly, using platinum for 20,000 turnovers in the first step (0.0025 mmoles) and then 1000 turnovers in the second step (0.10 mmoles). (302-075)
Analysis of Polymeric Silicone Amine Wax PSAW-2:1. 1 H NMR (toluene-d 8 , δ): 0.2 to 0.6 (broad m, 90H, SiCH 3 ), 0.6 to 1.0 (broad m, 72H, SiCH 2 CH 2 CH 2 NH 2 , SiCH 2 (CH 2 ) 16 CH 3 ), 1.0 to 1.8 (broad m, 288H, SiCH 2 CH 2 CH 2 NH 2 , SiCH 2 (CH 2 ) 16 CH 3 ), 2.5 to 2.9 (broad m, 32H, SiCH 2 CH 2 CH 2 NH 2 ) 3.3 to 3.7 (broad m, 16H, SiCH 2 CH 2 CH 2 NH 2 ). IR (cm −1 , diamond): 2958 sh, 2916 s, 2849 s (sp 3 C—H), 1467 w (sp 3 C—H), 1257 m (Si—CH 3 ), 1074 sh, 1015 (Si—O—Si) and 784 sh, 767 s (Si—CH 3 ).
Example 4
Preparation of Oligomeric Silicone Amine Wax (OSAW)
This examples describes the preparation of oligomeric silicone amine wax (OSAW) having both the long-chain alkyl group and the alkyl-amine group on each monomer unit.
Synthesis of Octadecyl Dichloro Silane (1)
The apparatus, a 2 L 3-neck RBF, was equipped with nitrogen inlet adapter (Teflon valve/stopper), thermocouple positioned to measure reaction solution temperature directly (with temperature controller) and 500 mL addition funnel. The addition funnel was placed on the center neck to allow the drops of Grignard reagent into the most efficiently mixed portion of the reaction solution. Toluene (370 mL) was added to the reaction flask after measurement of solution volume in the addition funnel, followed by trichlorosilane (100 g, 74.4 mL, 738 mmoles) from a syringe directly into the reaction solution. Octadecylmagnesium chloride in THF (369 mL of a 0.50 M solution or 185 mmoles) was transferred into the addition funnel. The Grignard reagent addition was started and the reaction solution temperature was allowed to warm with the slightly exothermic reaction. Upon completion of the addition the reaction solution was cloudy grey with microscopic salts but upon warming to 60 C the reaction solution became white as macroscopic crystals appeared in solution. The volatiles were removed by vacuum transfer using a dry ice/ethanol cooled receiver overnight. The resulting white slurry was extracted with hexane (1×80 mL, 2×20 mL) and transferred through a filter tip cannula equipped with Fisherbrand P8 (particle retention 20-25 um) into a separate flask. The filtrate was clear and colorless. The volatiles were removed to a pressure of <100mtorr which produced a viscous colorless oil. The oil was distilled trap-to-trap using an inverted ‘U’ shaped connector between the pot and receiver with the receiver cooled with dry ice/ethanol bath. To remove the product from the higher boiling bis-addition by-product a pot temperature of 300 C (thermocouple between the heating mantle and flask) was used with a pressure of less than 100 mtorr. During the distillation the inverted ‘U’ tube was also heated with a heat gun to drive over the distillate. The product is a clear colorless oil. This synthesis produced 48.6 g, 155 mmoles and 84.0% yield. 1 H NMR (toluene-d 8 , δ): 0.77 (t, 2H, Si—CH 2 ), 0.89 (t, 3H, octadecyl CH 3 ), 1.1-1.4 (m, 32H, CH 2 ), 5.30 (s, 1H, Si—H). IR (cm −1 , diamond): 2919 s, 2852 s (sp 3 C—H), 2203 in (Si—H), 1466 m (sp 3 C—H) and 553, 501 m (symm and asymm Si—Cl).
Please note: The trap contents (or trapped reaction volatiles) from the reaction solution contain excess trichlorosilane because a three fold excess was used in the reaction. The thawed trap material should be slowly added to water (to produce silicates and hydrochloric acid) or a solution of alcohol and quartenary amine (to produce alkoxy silicone and ammonium hydrochloride) to decompose the chlorosilane before pouring the solution into the waste.
Synthesis of Oligomeric Silane (3)
A 1 L, 3 neck RBF was equipped with a nitrogen inlet adapter (Teflon valve/stopper), thermocouple positioned to measure the reaction solution temperature directly (with temperature controller) and another inlet adapter attached to an oil filled bubbler. The apparatus was configured so nitrogen gas could be passed into the flask, across the surface of the reaction solution and out through the bubbler. Then toluene (300 mL) was added followed by octadecyl dichloro silane (1) (60 g, 192 mmoles) by syringe. Then water (2.59 g, 2.59 mL, 144 mmoles) was added to a 50 mL Schlenk flask and dissolved in THF (15 mL) before being pulled into a syringe. The reaction solution was stirred rapidly and nitrogen was flowing across the reaction surface as the solution of water/THF was added drop-wise to the center of the reaction vortex over 20 minutes. The reaction solution temperature did not increase significantly during water/THF addition. Then the reaction solution was stirred at RT for 15 minutes before being heated to 60 C for 5 minutes.
Oligo dichlorosilane (2) has been formed at this point, and while not isolated, was characterized as follows: 1 H NMR (toluene-d 8 , δ): 0.7 to 1.0 (broad m, 35H, SiCH 2 (CH 2 ) 16 CH 3 ), 1.2 to 1.7 (broad m, 224H, SiCH 2 (CH 2 ) 16 CH 3 ), 5.0 to 5.2 (broad m, 7H, SiH). IR (cm −1 , diamond): 2916 s, 2849 s (sp 3 C—H), 2163 m (Si—H), 1466 (sp 3 C—H), 1079 m, 1030 sh (Si—O—Si) and 464 m (Si—Cl).
After 5 minutes at about 60 C the sodium trimethylsilanolate solution was added (48.0 mL of a 1.0 M solution or 48.0 mmoles) by syringe. After another 5 minutes at about 60 C, triethyl amine (29.1 g, 40.4 mL, 288 mmoles) was added quickly by syringe into the center of the reaction solution vortex which turned the clear reaction solution opaque white. Then the reaction solution was stirred at 60 C for another 10 minutes before being allowed to cool toward RT. The volatiles were removed by vacuum transfer using a dry ice/ethanol cooled receiver (overnight) which produced a white paste. The product was isolated by extraction with hexane (1×80 mL and 2×40 mL) and each extract was transferred by cannula using a filter tip cannula equipped with Fisherbrand P8 filter paper (particle retention 20-25 um) into a separate Schlenk flask. The volatiles were removed from the clear colorless filtrate by vacuum transfer to produce a white solid. After preliminary vacuum, the solids were broken up before final vacuum to a pressure of <50 mtorr. The product, a white powder, weighed 50.7 g. The formula weight was determined by using end group analysis with proton NMR by comparing the integration of octadecyl methylenes against the silicon methyl groups. It was determined that n=7.2 repeat units so the formula weight was calculated to be 2312 so 50.7 g was 21.9 mmoles with reaction yield of 82.1%. 1 H NMR (toluene-d 8 , δ): 0.1 to 0.3 (broad m, 18H, SiCH 3 ), 0.7 to 1.0 (broad m, 35H, SiCH 2 (CH 2 ) 16 CH 3 ), 1.2 to 1.7 (broad m, 224H, SiCH 2 (CH 2 ) 16 CH 3 ), 5.0 to 5.2 (broad m, 7H, Si—H). IR (cm −1 , diamond): 2917 s, 2848 s (sp 3 C—H), 2161 m (Si—H), 1468 m (sp 3 C—H), 1075 m (Si—O—Si).
Synthesis of Oligomeric Silicone Amine Wax or OSAW (4)
A 250 mL, 3-neck RBF equipped with a nitrogen inlet adapter (Teflon valve/stopper), reflux condenser and suba seal was placed under vacuum to <200 mtorr and back flushed with nitrogen. Then oilgo silane (3) (10 g, 3.36 mmoles of polymer strands, n=9.4 formula weight of 2974 but containing 33.5 mmoles of silane) was added from a vial through the ‘suba seal’ orifice and the orifice fitted with a thermocouple positioned to measure the reaction solution temperature directly (with temperature controller). Toluene (6 mL) was added and the reaction solution was heated to 60 C. Allylamine (7.65 g, 10.0 mL, 134 mmoles) was added by syringe followed by a Karstedt's Catalyst (0.296 mL, 0.0335 mmoles platinum or enough for 1000 turnovers) which heated the solution slightly. Then the reaction solution was heated at 65 C for 2 days. Following sample analysis by FTIR that revealed a small Si—H peak at 2160 cm −1 , a little more allylamine (1.52 g, 2 mL, 26.7 mmoles) was added and the reaction solution was heated at 65 C for another day. Sample analysis by FTIR did not show an Si—H peak so the reaction solution was allowed cooled toward RT. Toluene (2 mL) was added as the reaction solution was cooling to RT to prevent solidification. Then the reaction solution was added drop-wise over 10 minutes to a separate Schlenk flask containing methanol (100 mL). Methanol precipitated the product as a white solid. The supernatant was removed by a filter tip cannula equipped with Fishebrand P8 filter paper (particle retention 20-25 um) and the precipitate was rinsed with methanol 2×100 mL before placing the product under vacuum to a pressure of <100 mtorr. The product (with n=9.4 and formula weight of 3510) is a white somewhat granular powder (8.97 g, 3.02 mmoles, 89.8% yield). 1 H NMR (toluene-d 8 , δ): 0.2 to 0.4 (broad m, 18H, SiCH 3 ), 0.7 to 1.0 (broad m, 49H, SiCH 2 CH 2 CH 2 NH 2 and SiCH 2 (CH 2 ) 16 CH 3 ), 1.2 to 1.8 (broad m, 126H, SiCH 2 (CH 2 ) 16 CH 3 and SiCH 2 CH 2 CH 2 NH 2 ), 2.6 to 2.9 (broad m, 14H, SiCH 2 CH 2 CH 2 NH 2 ), 3.6 to 3.7 (broad m, 14H, CH 2 NH 2 ). IR (cm −1 , diamond): 2917 s, 2849 s (sp 3 C—H), 1467 m (sp 3 C—H), 1066 s, 1036 s (Si—O—Si).
Example 5
Compositions of Quantum Dots with PSAW-1:1
Ligand exchange was accomplished by dissolving nanocrystals/quantum dots in hexane or toluene, adding an amino functional silicone, heating at 50° to 60° C. for 16 to 36 h, and removing the volatiles by vacuum transfer. (In general, ligand exchange is typically accomplished at 50° to 130° C. for 2 to 72 h.) The quantum yield and other parameters were maintained, and the nanocrystals were left in silicone as a clear oil.
In the glove box CdSe/CdS/ZnS nanocrystals (NCs), dissolved in toluene from the shell synthesis, were washed by precipitation with 2 volumes of ethanol, mixing by vortex mixer followed by centrifugation for 10 minutes. The supernatant was decanted and the NCs were dissolved in the same volume of toluene as the NC shell solution. Then the optical density (OD) was determined by dissolving a small amount of NC/ligand/toluene solution in toluene, measuring the OD at 460 nm then extrapolating back to the OD of the stock solution. The amount of PSAW used in the exchange was based upon the concentration of NCs dissolved in PSAW, as if the PSAW was the solvent. A NC concentration of between 25 and 400 was the normal range. Then the amount of toluene was calculated to produce a solution of 6 OD. The amount of toluene above the amount that was solubilizing the NCs was used to dissolve PSAW in a flask and was heated to 100 C. Then the solution of NCs/ligand/toluene was added drop-wise over 15 to 30 minutes followed by heating the exchange solution for 2 h at 100 C. The volatiles were removed by vacuum transfer to a pressure of less than 100 mtorr. The NCs/ligand is now a waxy solid that was dissolved into Part B epoxy (Locktite CL30) by THINKY mixer and then to produce a epoxy mixture capable of thermal cure mixed into Part A. The amount of Part A to B used was 2:1 weight ratio.
For example: NCs in shell growth solution (15 mL) were precipitated by combination with ethanol (30 mL), mixed and centrifuged for 10 minutes. The supernatant was decanted and the pellet was dissolved in toluene (15 mL). The optical density (OD) was measured by dissolution of a 0.1 mL sample into 4.0 mL toluene and the absorbance measured at 460 nm. An absorbance of 0.236 calculated an OD of 9.68. A portion of the washed NCs in toluene (6.2 mL) was to be used for ligand exchange with 0.60 g of PSAW to make 100 OD in PSAW. The total volume of toluene to be used was 10 mL and the exchange OD was projected occur at OD 6.0. Then to a flask was added PSAW (0.60 g) and toluene (3.8 mL) and the solution was heated to 100 C. The washed NCs in toluene (6.2 mL) were added drop-wise over 20 minutes and the solution was heated at 100 C for 120 minutes longer. Following ligand exchange the solution was cooled to room temperature and the volatiles removed by vacuum transfer to a pressure of less that 100 mtorr. The amount of NCs/ligand to be used in the formulation depends upon a number of other factors such as film thickness and desired white point and will not be described.
Example 6
Preparation of PSCAW
General Methods. All manipulations were performed under a dry, oxygen-free, nitrogen atmosphere using standard Schlenk technique. Dry, deoxygenated toluene, methanol, 4-pentenoic acid, and 1-octadecene (>95% by GC) were purchased from Aldrich and used without further purification. Karstedt's catalyst, 2.1 to 2.4 wt % in xylenes was obtained from Gelest, used without further purification, stored and handled inside the glove box. A 100× dilution of Karstedt's catalyst was produced by dissolving 0.10 mL of stock solution into 10 mL of toluene. (The stock solution contains 0.113 moles of platinum per mL so the 100× dilution contains 0.00113 mmoles platinum per mL solution.) The polysilane HMS-991 (1) was purchased from Gelest. The silane was purified by vacuum overnight to P<50 mtorr at room temperature (RT) and then handled inside the glove box. NMR chemical shift data were recorded with a Bruker FT NMR at 400 MHz for proton or 100 MHz for 13 C { 1 H} and are listed in ppm. IR analysis was obtained on a Nicolet 7200 FTIR equipped with an attenuated total reflectance (ATR) sampling accessory.
Synthesis of Polymeric Silicone Carboxylic Acid Wax (3). The apparatus was set up with a 100 mL, 3-neck RBF equipped with nitrogen inlet adapter (Teflon valve/stopper), thermocouple positioned to measure reaction solution temperature directly (with temperature controller) and short path distillation head with receiver. Additionally the distillation head was attached to a bubbler containing a one-way valve. The apparatus was configured so that upon attachment of a Schlenk line to the hose adapter, nitrogen gas could be passed into the reaction flask, across the surface of the reaction solution and out the bubbler attached to the distillation head. Also, the one way valve on the bubbler allowed vacuum to be applied to the whole apparatus, from the bubbler to the hose adapter.
After attachment to the Schlenk line, polysilane 1 (7.00 g, 4.38 mmoles of polymer strands with 100 mmoles of silane) was added followed by 1-octadecene (13.0 g, 16.0 mL, 50.0 mmoles) by syringe. The reaction apparatus was placed under vacuum until a pressure of less than 100 mtorr was reached and back flushed with nitrogen once. This vacuum step was preformed with the valve between the distillation head and bubbler open. Then toluene (30 mL) was added, nitrogen gas flow was adjusted to slowly pass through the apparatus and out the bubbler. Also coolant was circulated through the distillation head condense and the reaction solution temperature was set to 120° C. Distillation was continued until about half the toluene was collected or about 15 mL. Then toluene (15 mL) was added, the reaction solution was cooled to 60° C. and the distillation head was replaced by a nitrogen filled reflux condenser connected to the Schlenk line. The reaction solution was heated to 60° C. and Karstedt's catalyst (2.2 mL of a 100× dilution of stock solution with 2.50×10 −3 mmoles platinum or enough for 20,000 turnovers) was added by syringe. The reaction was exothermic and reached 130 C, and after the temperature dropped was heated at 90° C. for 3 h then the reaction solution was sampled and the volatiles removed for analysis. Analysis by FTIR and proton NMR indicated that the olefin had been consumed and the silane peak had been reduced in size by around 50%. The next step in the synthesis was performed without isolation of intermediate 2. IR (cm −1 , diamond): 2957 sh, 2916 s, 2850 s (sp3 C—H), 2160 m (Si—H).
The reaction solution was then cooled to 60° C. and 4-pentenoic acid (10.0 g, 10.19 mL, 100 mmoles) was added by syringe. The reaction experienced an exotherm, self heating to above 140° C., upon which the reaction mixture gelled and bumped gelled product into the condenser. The gelled product would slowly dissolve into toluene over a few days. IR (cm −1 , diamond): 3600 to 2300 broad (carboxylic acid OH), 2956 sh, 2916 s, 2849 s (sp2 C—H), 1709 s (carboxylic acid C═O), 1077 sh, 1015 s (Si—O—Si).
Example 7
Preparation of PS2CAW
General Methods.
All manipulations were performed under a dry, oxygen-free, nitrogen atmosphere using standard Schlenk technique. Dry, deoxygenated toluene, methanol and 1-octadecene (>95% by GC) were purchased from Aldrich and used without further purification. Allyl succinic anhydride was purchased from TCI America and distilled before use. Karstedt's catalyst, 2.1 to 2.4 wt % in xylenes was obtained from Gelest, used without further purification, stored and handled inside the glove box. A 100× dilution of Karstedt's catalyst was produced by dissolving 0.10 mL of stock solution into 10 mL of toluene. (The stock solution contains 0.113 moles of platinum per mL.) The polysilane (1) or “polyMethylHydrosiloxanes, Trimethylsilyl terminated” with n of about 6 was purchased as a special order from Genesee Polymers Corp in Burton, Mich. The silane was purified by vacuum overnight to P<50 mtorr at room temperature (RT) and then handled inside the glove box. NMR chemical shift data were recorded with a Bruker FT NMR at 400 MHz for proton or 100 MHz for 13 C { 1 H} and are listed in ppm. IR analysis was obtained on a Nicolet 7200 FTIR equipped with an attenuated total reflectance (ATR) sampling accessory. The polysilane silicone (1) was characterized as follows: 1 H NMR (toluene-d 8 , δ): 0.16 (m, 36H, SiMe), 4.93 (m, 6H, Si—H); IR (cm −1 , diamond): 2961 w (sp3 C—H), 2161 m (Si—H), 1257 m (sp3 C—H), 1039 s (Si—O—Si).
Synthesis of Polymeric Silicone Carboxylic Acid Wax (4)
The apparatus was set up with a 50 mL, 3-neck RBF equipped with nitrogen inlet adapter (Teflon valve/stopper), thermocouple positioned to measure reaction solution temperature directly (with temperature controller) and short path distillation head with receiver. Additionally the distillation head was attached to a bubbler containing a one-way valve. The apparatus was configured so that upon attachment of a Schlenk line to the hose adapter, nitrogen gas could be passed into the reaction flask, across the surface of the reaction solution and out the bubbler attached to the distillation head. Also, the one way valve on the bubbler allowed vacuum to be applied to the whole apparatus, from the bubbler to the hose adapter.
After attachment to the Schlenk line, polysilane 1 (5.00 g, 9.56 mmoles of polymer strands with 57.4 mmoles of silane) was added followed by 1-octadecene (7.42 g, 9.17 mL, 28.7 mmoles) by syringe. The reaction apparatus was placed under vacuum until a pressure of less than 100 mtorr was reached and back flushed with nitrogen once. This vacuum step was preformed with the valve between the distillation head and bubbler open. Then toluene (15 mL) was added, nitrogen gas flow was adjusted to slowly pass through the apparatus and out the bubbler. Also coolant was circulated through the distillation head condenser, the receiver was cooled with dry ice/ethanol and the reaction solution temperature was set to 120 C. Distillation was continued until about half the toluene was collected or about 12 to 13 mL. Then toluene (15 mL) was added, the reaction solution was cooled to 60 C and the distillation head was replaced by a nitrogen filled reflux condenser connected to the Schlenk line. The reaction solution was heated to 60 C and Karstedt's catalyst (1.27 mL of a 100× dilution of stock solution with 1.43×10 −3 mmoles platinum or enough for 20,000 turnovers) was added by syringe. The reaction exothermed to 130 C and after the temperature dropped was heated at 90 C for 3 h. then the reaction solution was sampled and the volatiles removed for analysis. Analysis by FTIR and proton NMR indicated that the olefin had been consumed and the silane peak had been reduced in size by around 50%. The next step in the synthesis was performed without isolation of intermediate 2.
The reaction solution was then cooled to 60 C and allyl succinic anhydride (4.02 g, 3.43 mL, 28.7 mmoles) was added by syringe. Immediately following allyl succinic anhydride, Karstedt's catalyst (2.54 mL of a 100× dilution of the stock solution or 2.86×10 −3 mmoles of platinum, enough for 10,000 turnovers) was added by syringe. The solution temperature was then set to 110 C and the solution heated overnight. A sample was prepared for analysis by addition of a 0.3 mL sample drop-wise to a rapidly stirring solution of 2 mL methanol. Following precipitation the supernatant was decanted and the white waxy sample washed with methanol (2 mL) before being prepared for analysis by removal of the volatiles by vacuum transfer. Proton NMR indicated a significant reduction of the Si—H peak with lumpy resonances integrating to about 0.25 of the analysis of intermediate 2. Therefore, since other peaks obscure integration in the Si—H region due to a small amount of double bond migration, FTIR analysis was used to provide an accurate determination. FTIR determined almost complete disappearance of the Si—H peak. However the reaction solution was heated at 120 C overnight once again to insure that the reaction had been driven to completion. Subsequent sample preparation and analysis determined that the reaction was complete.
Following consumption of the silane, toluene (2 mL) was added and the reaction solution was cooled to room temperature. The reaction solution was transferred into methanol (280 mL) dropwise by cannula in a 500 mL Schlenk flask which formed a white precipitate. Stirring was ceased after 5 minutes and the precipitate allowed to settle. Then the supernatant was removed by filter tip cannula equipped with Fisherbrand P8 filter paper (particle retention 20-25 um) and the precipitate washed with methanol (40 mL). Although the anhydride product 3 was not hydrolyzed to succinic acid in the next step, analysis of polymeric silicone anhydride wax 3 was available in the analytical section. 1 H NMR (toluene-d 8 , δ): 0.15 to 0.40 (m, 36H, SiMe), 0.55 to 0.95 (m, 21H, SiCH 2 CH 2 , (CH 2 ) 16 CH 3 ), 1.25 to 1.75 (m, 114H, SiCH 2 (CH 2 ) 16 CH 3 , SiCH 2 CH 2 CH 2 CH), 1.8 to 2.8 (m, 9H, CH 2 CH(CO 2 H)CH 2 CO 2 H). IR (cm −1 , diamond): 2958 sh, 2917 s, 2849 s (sp3 C—H), 1863 m, 1782 s (anhydride symm & asymm), 1257 m (sp3 C—H), 1062 sh, 1021 s (Si—O—Si).
Water (16 mL, 888 mmoles) was added to the reaction flask and a thin wire thermocouple was positioned between the flask and heating mantle to roughly measure the reaction solution temperature. The reaction solution was heated at 130 C under nitrogen overnight which produced a goopy white opaque solution. After volatiles were removed using a dry ice/ethanol cooled supplementary trap the volatiles were broken up before ultimate volatiles removal by vacuum on the Schlenk line until a pressure of <50 mtorr was reached for 30 minutes. The product, a semi-crystalline white solid (9.79 g, 5.75 mmoles or 60.2% yield) was stored in the glove box. 1 H NMR (CDCl 3 , δ): −0.05 to 0.15 (m, 36H, SiMe), 0.35 to 0.60 (m, 12H, SiCH 2 CH 2 ), 0.86 (t, 9H, (CH 2 ) 16 CH 3 ), 1.15 to 1.80 (m, 108H, SiCH 2 (CH 2 ) 16 CH 3 , SiCH 2 CH 2 CH 2 CH), 2.20 to 3.10 (m, 9H, CH 2 CH(CO 2 H)CH 2 CO 2 H). IR (cm −1 , diamond): 3600 to 2300 broad (carboxylic acid OH), 2958 sh, 2921 s, 2849 s (sp2 C—H), 1707 s (carboxylic acid C═O), 1257 m (sp3 C—H), 1074 sh, 1021 s (Si—O—Si).
Example 8
Preparation of OSCAW
General Methods.
All manipulations were performed under a dry, oxygen-free, nitrogen atmosphere using standard Schlenk technique. The reagents octadecyl magnesium chloride (0.5 M in tetrahydrofuran or THF), trichlorosilane, sodium trimethylsilanolate (1.0 M in THF) and triethylamine were obtained from Sigma-Aldrich and stored in the glove box before being used without further purification. The solvents THF, toluene and hexanes were purchased dry and deoxygenated from Fisher Chemical, used without further purification and handled by Schlenk technique. The 4-pentenoic acid was obtained from Sigma-Aldrich and stored in the glove box before being used without further purification. Karstedt's catalyst, 2.1 to 2.4 wt % in xylenes was obtained from Gelest and used without further purification. (The stock solution contains 0.113 moles of platinum per mL.) NMR chemical shift data were recorded with a Bruker FT NMR at 400 MHz for 1 H and are listed in ppm. IR analysis was obtained on a Nicolet 7200 FTIR equipped with an attenuated total reflectance (ATR) sampling accessory.
Synthesis of Oligomeric Silane
Synthesis of Octadecyl Dichloro Silane (1)
The apparatus, a 2 L 3-neck RBF, was equipped with nitrogen inlet adapter (Teflon valve/stopper), thermocouple positioned to measure reaction solution temperature directly (with temperature controller) and 500 mL addition funnel. The addition funnel was placed on the center neck to allow the drops of Grignard reagent into the most efficiently mixed portion of the reaction solution. Toluene (370 mL) was added to the reaction flask after measurement of solution volume in the addition funnel, followed by trichlorosilane (100 g, 74.4 mL, 738 mmoles) from a syringe directly into the reaction solution. Octadecylmagnesium chloride in THF (369 mL of a 0.50 M solution or 185 mmoles) was transferred into the addition funnel. The Grignard reagent addition was started and the reaction solution temperature was allowed to warm with the slightly exothermic reaction. Upon completion of the addition the reaction solution was cloudy grey with microscopic salts but upon warming to 60 C the reaction solution became white as macroscopic crystals appeared in solution. The volatiles were removed by vacuum transfer using a dry ice/ethanol cooled receiver overnight. The resulting white slurry was extracted with hexane (1×80 mL, 2×20 mL) and transferred through a filer tip cannula equipped with Fisherbrand P8 (particle retention 20-25 um) into a separate flask. The filtrate was clear and colorless. The volatiles were removed to a pressure of <100 mtorr which produced a viscous colorless oil. The oil was distilled trap-to-trap using an inverted ‘U’ shaped connector between the pot and receiver with the receiver cooled with dry ice/ethanol bath. To remove the product from the higher boiling bis-addition by-product a pot temperature of 300 C (thermocouple between the heating mantle and flask) was used with a pressure of less than 100 mtorr. During the distillation the inverted ‘U’ tube was also heated with a heat gun to drive over the distillate. The product is a clear colorless oil. This synthesis produced 48.6 g, 155 mmoles and 84.0% yield. 1 H NMR (toluene-d 8 , δ): 0.77 (t, 2H, Si—CH 2 ), 0.89 (t, 3H, octadecyl CH 3 ), 1.1-1.4 (m, 32H, CH 2 ), 5.30 (s, 1H, Si—H). IR (cm −1 , diamond): 2921 s, 2852 s (sp 3 C—H), 2205 m (Si—H), 1466 m (sp 3 C—H) and 553, 501 m (symm and asymm Si—Cl).
Please note: The trap contents (or trapped reaction volatiles) from the reaction solution contain excess trichlorosilane because a three fold excess was used in the reaction. The thawed trap material should be slowly added to water (to produce silicates and hydrochloric acid) or a solution of alcohol and quartenary amine (to produce alkoxy silicone and ammonium hydrochloride) to decompose the chlorosilane before pouring the solution into the waste.
Synthesis of Oligomeric Silane (3)
A 1 L, 3 neck RBF was equipped with a nitrogen inlet adapter (Teflon valve/stopper), thermocouple positioned to measure the reaction solution temperature directly (with temperature controller) and another inlet adapter attached to an oil filled bubbler. The apparatus was configured so nitrogen gas could be passed into the flask, across the surface of the reaction solution and out through the bubbler. Then toluene (300 mL) was added followed by octadecyl dichloro silane (1) (60 g, 192 mmoles) by syringe. Then water (2.59 g, 2.59 mL, 144 mmoles) was added to a 50 mL Schlenk flask and dissolved in THF (15 mL) before being pulled into a syringe. The reaction solution was stirred rapidly and nitrogen was flowing across the reaction surface as the solution of water/THF was added drop-wise to the center of the reaction vortex over 20 minutes. The reaction solution temperature did not increase significantly during water/THF addition. Then the reaction solution was stirred at RT for 15 minutes before being heated to 60 C for 5 minutes.
Oligo dichlorosilane (2, n=7) has been formed at this point but was not isolated in this procedure. However, analysis for this species is included (vide infra) 1 H NMR (toluene-d 8 , δ): 0.7 to 1.0 (broad m, 35H, SiCH 2 (CH 2 ) 16 CH 3 ), 1.2 to 1.7 (broad m, 224H, SiCH 2 (CH 2 ) 16 CH 3 ), 5.0 to 5.2 (broad m, 7H, SiH). IR (cm −1 , diamond): 2916 s, 2849 s (sp 3 C—H), 2163 m (Si—H), 1466 (sp 3 C—H), 1079 m, 1030 sh (Si—O—Si) and 464 m (Si—Cl).
After 5 minutes at about 60 C the sodium trimethylsilanolate solution (48.0 mL of a 1.0 M solution or 48.0 mmoles) was added by syringe. After another 5 minutes at about 60 C, triethyl amine (29.1 g, 40.4 mL, 288 mmoles) was added quickly by syringe into the center of the reaction solution vortex which turned the clear reaction solution opaque white. Then the reaction solution was stirred at 60 C for another 10 minutes before being allowed to cool toward RT. The volatiles were removed by vacuum transfer using a dry ice/ethanol cooled receiver (overnight) which produced a white paste. The product was isolated by extraction with hexane (1×80 mL and 2×40 mL) and each extract was transferred by cannula using a filter tip cannula equipped with Fisherbrand P8 filter paper (particle retention 20-25 um) into a separate Schlenk flask. The volatiles were removed from the clear colorless filtrate by vacuum transfer to produce a white solid. After preliminary vacuum, the solids were broken up before final vacuum to a pressure of <50 mtorr. The product, a white powder, weighed 50.7 g. The formula weight was determined by using end group analysis with proton NMR by comparing the integration of octadecyl methylenes against the silicon methyl groups. It was determined that n=7.2 repeat units so the formula weight was calculated to be 2312 so 50.7 g was 21.9 mmoles with reaction yield of 82.1%. 1 H NMR (toluene-d 8 , δ): 0.1 to 0.3 (broad m, 18H, SiCH 3 ), 0.6 to 0.9 (broad m, 35H, SiCH 2 (CH 2 ) 16 CH 3 ), 1.2 to 1.7 (broad m, 224H, SiCH 2 (CH 2 ) 16 CH 3 ), 4.8 to 5.0 (broad m, 7H, Si—H). IR (cm −1 , diamond): 2956 sh, 2917 s, 2848 s (sp 3 C—H), 2161 m (Si—H), 1468 m (sp 3 C—H), 1065 m, 1075 sh (Si—O—Si).
Synthesis of Oligomeric Silicone Carboxylic Acid Wax or OSCAW
A 100 mL 3-neck RBF was set up on the Schlenk line with a reflux condenser, thermocouple positioned to measure the reaction solution temperature connected to a temperature controller and nitrogen inlet adapter. After vacuum and back flush with nitrogen 3 times, polysilane 3 was added (5 g, 16.7 mmoles estimated by using a polymer repeat unit fwt of 298.51) from a vial after storage and weighing in the glove box. Then reaction flask was vac again once to less than 100 mtorr and back flushed with nitrogen gas. Toluene (2 mL) and 4-pentanoic acid (2.77 g, 2.93 mL, 27.7 mmoles) were added and the reaction solution was heated to 60 C. Karstedt's catalyst (0.739 ml or 8.35×10 −4 mmoles of a 100× dilution of the stock solution or enough for 20,000 turnovers) was added and the solution was heated at 60 C for a couple of hours. Then the temperature was increased by 20 C incrementally and the reaction solution was heated at 120 C overnight. Following sample analysis by FTIR and 1 H NMR, indicating the silane had been consumed, toluene (2 mL) was added before the reaction solution was cooled to room temperature to prevent solidification. Then the reaction solution was added dropwise to a separate RBF containing MeOH (45 mL) to precipitate the product. (Please note that 4-pentanoic acid is soluble in MeOH.) The supernatant was removed by a filter tip cannula equipped with Fisherbrand filter paper (particle retention 20-25 um) and the precipitate rinsed with MeOH (10 mL). The volatiles were removed and the solids broken up to facilitate drying before final vacuum to p<50 mtorr to leave a slightly off white powder, 4.17 g, 1.37 mmoles, 63.7% yield (based upon a silane with n=7.2). 1 H NMR (toluene-d 8 , δ): 0.25 to 0.50 (broad m, 18H, SiMe), 0.70 to 1.20 (broad m, 49H, SiCH 2 CH 2 CH 2 CH 2 CO 2 H and SiCH 2 (CH 2 ) 16 CH 3 ), 1.20 to 1.75 (broad m, 252H, SiCH 2 (CH 2 ) 16 CH 3 , SiCH 2 CH 2 CH 2 CH 2 CO 2 H and SiCH 2 CH 2 CH 2 CH 2 CO 2 H), 2.2 to 2.7 (broad m, 14H, SiCH 2 CH 2 CH 2 CO 2 H) and 13.5 to 15.5 (broad m, 14H, CH 2 CO 2 H). IR (cm −1 , diamond): 2500 to 3500 (broad CO 2 H), 2917 s, 2849 s (sp 3 C—H), 1711 m (C═O), 1467 s (sp 3 C—H), 1077 s, 1036 sh (Si—O—Si).
Example 9
Preparation of OS2CAW
The Oligomeric Silicone Di-Carboxylic Acid Wax (OS2CAW) was prepared by two methods.
General Methods.
All manipulations were performed under a dry, oxygen-free, nitrogen atmosphere using standard Schlenk technique. The solvents toluene and methanol were purchased from Fisher already deoxygenated and dry in 1 L containers and used without further purification. Dimethoxyethane (DME) was purchased from Aldrich already dry and deoxygenated in 1 L containers also and used without further purification. Allyl succinic anhydride was purchased from TCI America and distilled before use. Platinum (II) acetylacetonate [Pt(acac)2] was purchased from Strem Chemical and used without further purification. In the glove box 50 mg of Pt(acac) 2 was dissolved in 10 mL of DME to produce a solution containing 1.27×10 −2 mmoles Pt/mL solution. Speier's catalyst, hexachloro platinic acid hydrate was purchased from Aldrich and used without further purification. (To make a stock solution 55 mg was dissolved in 10.0 mL of DME producing 1.34×10 −2 mmoles Pt/mL catalyst solution.). NMR chemical shift data were recorded with a Bruker FT NMR at 400 MHz for 1 H and are listed in ppm. IR analysis was obtained on a Nicolet 7200 FTIR equipped with an attenuated total reflectance (ATR) sampling accessory.
The octadecyl dichloro silane (1) is characterized as follows: 1 H NMR (toluene-d 8 , δ): 0.77 (t, 2H, Si—CH 2 ), 0.89 (t, 3H, octadecyl CH 3 ), 1.1-1.4 (m, 32H, CH 2 ), 5.30 (s, 1H, Si—H); IR (cm −1 , diamond): 2919 s, 2852 s (sp 3 C—H), 2203 m (Si—H), 1466 m (sp 3 C—H) and 553, 501 m (symm and asymm Si—Cl).
Method 1
Synthesis of Allyl Succinic Acid
Water (321 g, 321 mL, 1.78 moles) was placed in a 1 L, 3-neck RBF and briefly vacuumed to remove oxygen. Then allyl succinic anhydride (50 g, 42.7 mL, 357 mmoles) was added and the reaction solution heated to 110 C overnight. The reaction solution was then cooled to room temperature and the volatiles removed from a sample to prepare for FTIR analysis. After confirming the anhydride had been converted to carboxylic acid, the volatiles were removed by vacuum transfer while stirring the reaction solution at 30 C. The reaction flask temperature was maintained with a temperature controller while being monitored using a thin wire thermocouple placed between the heating mantle and reaction flask. As the product began to solidify, the solids were broken up to facilitate drying. After the majority of the water had been removed, the flask was connected directly to the Schlenk line to achieve a pressure <20 mtorr overnight. The product is a white solid (55.6 g, 352 mmoles, 98.5% yield). 1 H NMR (DMSO-d 6 , δ): 2.07 to 2.35 and 2.42 to 2.52 (m, 4H, CH 2 ═CHCH 2 CH(CO 2 H)CH 2 CO 2 H), 2.66 to 2.74 (m, 1H, CH 2 CH(CO 2 H)CH 2 ), 5.00 to 5.09 (m, 2H, CH 2 ═CHCH 2 ) 5.6 to 5.78 (m, 1H, CH 2 ═CHCH 2 CH). IR (cm −1 , diamond): 2300 to 3700 (broad CO 2 H), 3029 w (sp2 C—H), 2978w, 2921w (sp3 C—H), 1689 s (C═O).
Synthesis of Oligomeric Silicone Di-Carboxylic Acid Wax or OS2CAW
To a 250 mL, 4-neck RBF in the glove box was added oligomeric silane (34.2 g, 114 mmoles estimated of silane repeat units by using a fwt of 298.51; from Example 8) and allyl succinic acid (19 g, 120 mmoles) as dry powders. Before removal from the glove box the flask was equipped with a nitrogen inlet adapter and three Suba-seal stoppers. Upon attachment to the Schlenk line, the flask was equipped with a reflux condenser and thermocouple positioned to measure the reaction solution temperature directly. Also a heating mantle and temperature controller was connected to the thermocouple. Then DME (20 mL) was added which formed a slurry. While the mixture was being heated to 80 C the slurry transformed to a solution at about 60 C and was mixing easily at 80 C. However the reaction solution was turbid and separated into two phases when the stirring was ceased. Then the catalyst solution (0.189 mL of Pt(acac) 2 /DME, or 2.40×10 −3 mmoles or enough for 50,000 turnovers) was added to the reaction solution and after about 15 minutes the temperature was set to 100 C to gently reflux overnight.
After being heated at for about 16 h the reaction solution was homogenous. To prevent solidification during sample withdrawal, about 0.3 ml of toluene was pulled into the syringe before the 0.3 mL sample was withdrawn. Vacuum transfer of the volatiles produced a waxy solid. FTIR analysis determined that the silane had been consumed which was confirmed by 1 H NMR. Then the reaction solution was diluted with 20 mL DME before cooling to room temperature to prevent solidification. The reaction solution was transferred drop-wise into MeOH (300 mL) in a 1 L Schlenk flask which precipitated the product. After stirring for 10 minutes the supernatant was removed by filter tip cannula equipped with Fisherbrand P8 filter paper (20-25 um particle retention). The volatiles were removed from the product to p<100 mtorr before water (540 mL, 30 moles) was added to the reaction flask to hydrolyze the product to back to succinic acid. Then the reaction flask was fitted with a reflux condenser and heated at 100 C using a temperature controller with thermocouple between flask and heating mantle. The reaction solution was heated overnight under nitrogen.
After confirmation by FTIR of conversion to acid the product was isolated by removal of volatiles using a supplementary trap cooled with dry ice. As the water was removed the solids were broken up to facilitate drying. Eventually product was vacuumed to p<20 mtorr overnight. The product was a white powder 37.3 g, 119 mmoles, 73.6% yield with n=6.5 repeat units for the oligomer. 1 H NMR (toluene-d 8 , δ): 0.2 to 0.5 (broad m, 18H, SiCH 3 ), 0.7 to 1.1 (broad m, 49H, SiCH 2 CH 2 CH 2 and SiCH 2 (CH 2 ) 16 CH 3 ), 1.2 to 1.8 (broad m, 126H, SiCH 2 (CH 2 ) 16 CH 3 and SiCH 2 CH 2 CH 2 CHCO 2 H), 2.2 to 2.7 (broad m, 21H, SiCH 2 CH 2 CH 2 CH(CO 2 H)CH 2 CO 2 H) and 13.5 to 15.5 (broad m, 14H, CO 2 H). IR (cm −1 , diamond): 2500 to 3500 (broad CO 2 H), 2958 sh, 2916 s, 2849 s (sp 3 C—H), 1711 m (C═O), 1467 s (sp 3 C—H), 1066 s, 1020 sh (Si—O—Si).
Method 2
Synthesis of Succinic Anhydride Wax (2)
To a 100 mL, 4-neck RBF equipped with a nitrogen inlet adapter and thermocouple with temperature controller was added dichlorosilane 1 (10.0 g, 31.9 mmoles) and allyl succinic anhydride (4.48 g, 3.82 mL, 31.9 mmoles) which formed a turbid solution. The turbid solution separated into 2 phases when the stirring was ceased. The reaction solution was heated to 80 C and the Speir's catalyst (0.955 mL, 1.28×10-4 mmoles platinum of a 100× dilution of the stock solution or enough for 250,000 turnovers) was added all at once in a stream. No exothermic reaction was observed but the reaction solution was heated overnight at 80 C. After about 16 h at 80 C the reaction solution was clear light yellow and remained in one phase when the stirring was ceased. A sample 0.2 mL was withdrawn into a long 18 Ga needle using a syringe containing 0.3 mL of toluene to prevent solidification of the sample in the needle. The volatiles were removed and the sample analyzed by FTIR and 1H NMR and determined the reaction was complete. This product was not isolated but taken to the next reaction directly. Analysis for the succinic anhydride wax 2 is provided. 1 H NMR (CDCl 3 , δ): 0.55 to 0.95 (m, 7H, CH 3 (CH 2 ) 16 CH 2 SiCH 2 CH 2 ), 1.05 to 1.50 (m, 36H, CH 3 (CH 2 ) 16 CH 2 SiCH 2 CH 2 CH 2 CH), 1.70 to 2.00 (m, 3H, CH 2 Si(CH 2 ) 3 CH(CO 2 H)CH 2 CO 2 H). IR (cm −1 , diamond): 2958 sh, 2915 s, 28449 s (sp3 C—H), 1856 m, 1774 s (symm and asymm anhydride C═O), 522 s, 472 m (Si—Cl).
Synthesis of Oligomeric Silicone Succinic Anhydride Wax (3)
Toluene (25 mL) was added to the reaction flask and the reaction solution cooled to RT. Water (0.287 g, 16.0 mmoles) was weighed on an analytical balance and then dissolved in DME (2 mL) in the glove box before being withdrawn into a syringe. The reaction apparatus was modified under positive nitrogen pressure, by connection of a nitrogen filled bubbler to the standard taper that was on the opposite side from the nitrogen inlet adapter of the reaction flask. The nitrogen gas was adjusted to gently flow across the reaction solution and out the bubbler by slightly increasing nitrogen pressure above atmospheric pressure. The stopper in the center of the flask was changed for a suba seal and the water/DME filled syringe was positioned on the center opening so the water solution could be dropped directly into the vortex of the reaction solution. Then the water/DME solution was added drop-wise while stirring to reaction solution over 20 minutes. The reaction solution was stirred at RT for 15 more minutes before sodium trimethyl silenolate (16.0 mL, 16 mmoles) was added in a stream all at once. Again the reaction solution was stirred for 15 minutes at RT then heated to 60 C for 5 minutes before cooling to RT. The thermocouple and bubbler were replaced with stoppers and the volatiles were removed by vacuum transfer using a supplementary trap cooled with dry ice/ethanol overnight. After about 16 h under vacuum the reaction flask was connected directly to the vacuum line until a pressure of less than 500 mtorr was attained. FTIR and 1 H NMR analysis show the Si—Cl bonds have been hydrolyzed to Si—O—Si bonds. Also the product had between 6 and 8 repeat units by end group analysis. The product was not isolated but was taken directly to the next step without purification. 3 (n=7): 1 H NMR (toluene-d 8 , δ): 0.05 to 0.15 (m, 18H, SiMe), 0.40 to 0.65 (m, 28H, CH 2 CH 2 SiCH 2 CH 2 ), 0.86 (t, 21H, CH 3 CH 2 ), 1.15 to 1.95 m, 252H, CH 3 (CH 2 ) 16 CH 2 SiCH 2 CH 2 CH 2 CH), 2.4 to 3.2 (m, 21H, CH 2 Si(CH 2 ) 3 CH(CO 2 H)CH 2 CO 2 H); IR (cm −1 , diamond): 2858 sh, 2917 s, 2849 s (sp 3 C—H), 1862 m, 1781 s symm & asymm anhydride), 1466 m (sp 3 C—H), 1066 s, 1010 sh (Si—O—Si).
Synthesis of Oligomeric Silicone Di-Carboxylic Acid Wax or OS2CAW (4)
The reaction flask was equipped with a thermocouple positioned to measure the temperature of the reaction solution and water (25 mL, 1.39 moles) was added for the hydrolysis reaction. The reaction solution was heated to 60 C for 2 h. Then the volatiles were removed from a reaction sample which produced a white powder that was insoluble in toluene, chloroform and DMSO. FTIR analysis indicated that the reaction was finished and that the anhydride had been converted to acid. Then the thermocouple was replaced with a stopper before the volatiles were removed by vacuum transfer using a supplementary trap cooled with dry ice/ethanol overnight. After being subjected to vacuum for about 16 h most of the water had been removed so the large chunks of solids were broken up before the product vacuumed on the Schlenk line to a pressure of less than 50 mtorr overnight. The product (n=7) is a white solid 9.93 g, 3.89 mmoles or 97.7% yield. IR (cm −1 , diamond): 2500 to 3500 broad (carboxylic acid OH), 2958 sh, 2916 s, 2849 s (sp3 C—H), 1704 s (carboxylic acid C═O), 1077 sh, 1009 s (Si—O—Si).
Example 10
Preparation of EO-PS2CAW
General Methods.
All manipulations were performed under a dry, oxygen-free, nitrogen atmosphere using standard Schlenk technique. Dry, deoxygenated toluene was purchased from Fisher and used without further purification. Dry, deoxygenated dimethoxyethane (DME) was purchased from Aldrich and used without further purification. Allyloxy(triethylene oxide), methyl ether, 95% (Mn=3) was purchased from Gelest and used without further purification. Karstedt's catalyst, 2.1 to 2.4 wt % in xylenes was obtained from Gelest, used without further purification, stored and handled inside the glove box. A 100× dilution of Karstedt's catalyst was produced by dissolving 0.10 mL of stock solution into 10 mL of toluene. (The stock solution contains 0.113 moles of platinum per mL.) The polysilane (1) or “polyMethylHydrosiloxanes, Trimethylsilyl terminated” with Mn of about 6 was purchased as a special order from Genesee Polymers Corp in Burton, Mich. The silane was purified by vacuum overnight to P<50 mtorr and then handled inside the glove box. NMR chemical shift data were recorded with a Bruker FT NMR at 400 MHz for proton or 100 MHz for 13 C { 1 H} and are listed in ppm. IR analysis was obtained on a Nicolet 7200 FTIR equipped with an attenuated total reflectance (ATR) sampling accessory. Polysilane silicone (GP-1015 with n=6)) (1) is characterized as follows: 1 H NMR (toluene-d 8 , δ): 0.16 (m, 36H, SiMe), 4.93 (m, 6H, Si—H); IR (cm −1 , diamond): 2961 w (sp3 C—H), 2161 m (Si—H), 1257 m (sp2 C—H), 1039 s (Si—O—Si).
Synthesis of Polymeric Silicone Amine Wax (4)
A 500 mL, 4-neck RBF was equipped with a nitrogen inlet adapter, distillation head with receiver and thermocouple was attached to the Schlenk line. Additionally the distillation head was attached to a bubbler containing a one-way valve. The apparatus was configured so that upon attachment of a Schlenk line to the hose adapter, nitrogen gas could be passed into the reaction flask, across the surface of the reaction solution and out the bubbler attached to the distillation head. Also, the one way valve on the bubbler allowed vacuum to be applied to the whole apparatus, from the bubbler to the hose adapter. The thermocouple was attached to a heating mantle with temperature controller to maintain the desired reaction solution temperature. The apparatus was placed under vacuum to a pressure of less than 100 mtorr before being back flushed with nitrogen. This vacuum step was preformed with the valve between the distillation head and bubbler open.
Then polysilane 1 (34.2 g, 65.3 mmoles of polymer strands with n=6) was added followed by allyloxy(triethylene oxide), methyl ether (40 g, 196 mmoles) along with toluene (160 mL). The receiver was cooled in a dry ice/ethanol bath and the reaction flask was heated to 130 C while nitrogen was passed across the surface of the reaction solution from the inlet adapter and out through the distillation head and bubbler. After collection of about 150 mL of distillate the reaction solution was sampled for analysis. The volatiles were removed from the sample for analysis by 1H NMR in toluene-D8. (To determine the relative amounts of reactants, the OMe peak at 3.1 pm was set to integrate at 9 which was measured against the Si—H peak at 4.9 ppm. Unfortunately the Si—H peak splits one of the protons of that terminal allyl multiplet and can not be integrated directly. The two terminal allyl protons are well separated and along with the other allyl proton can be used to determine the amount of allyloxy(triethylene oxide) in the reaction mixture. The multiplet from non-overlapped terminal allyl proton at 5.2 ppm was averaged with the other non-overlapped allyl proton multiplet at 5.7 ppm to determine the integration for terminal one allyl proton. Then the silane was the difference between the allyl proton and silane combined with the other terminal allyl proton. The analysis demonstrated that the stoichiometry of the poly silane and allyloxy(triethylene oxide) was close enough to continue to the hydrosilation reaction.
After heating the reaction solution to 60 C Karstedt's catalyst (1.72 mL of a 100× dilution of the stock solution with 1.94×10 −3 mmoles platinum or enough for 100,000 turnovers) was added to the reaction solution. The solution temperature mildly exothermed and was then heated at 100 C overnight. Analysis of reaction solution sample determined the reaction was 90% complete so another aliquot of Karstedt's catalyst (0.86 mL, 9.72×10 −4 moles of platinum a 100× dilution or enough for 200,000 turnovers) was added and the reaction solution heated overnight at 100 C. Analysis after volatiles removal the reaction was complete as determined by consumption of allyl.
A 12.9 mL portion of the reaction solution (12.0 g or 10.5 mmoles of polysilane 2) was used in the next reaction. In the glove box allyl succinic acid (5 g, 31.6 mmoles) was added to a 100 mL 3-neck RBF equipped with thermocouple and nitrogen adapter. Then on the Schlenk line polysilane 2 was added by syringe and the reaction solution was heated to 80 C before Karstedt's Catalyst (0.316 mL, 3.57×10 −6 mmoles platinum from a 10,000× dilution or enough for 1,000,000 turnovers was added. The reaction solution slightly exothermed and then the temperature was set to 100 C overnight. Since analysis determined the reaction was still incomplete, the reaction solution temperature was reduced to 80 C and DME (3.0 mL) was added to allow the reaction solution to stir efficiently. Then Karstedt's Catalyst (1.27 mL, 1.43×10 −4 moles platinum of the 1000× dilution or enough for 20,000 turnovers) was added and the reaction solution heated at 100 C overnight. After sample preparation analysis determined the silane had been consumed but the succinic acid had been partially converted to anhydride, i.e. it was a mixture of 3a and 3b. 1 H NMR (toluene-d 8 , δ): 0.05 to 0.25 (m, 36H, SiMe), 0.50 to 0.70 (m, 6H, SiCH 2 CH 2 ), 1.50 to 1.70 (m, 6H, SiCH 2 CH 2 CH 2 O), 3.10 (s, 9H, OCH 3 ), 3.25 to 3.65 (m, 42H, CH 2 CH 2 CH 2 OCH 2 CH 2 O) n , 4.80 to 4.90 (m, 3H, SiH). IR (cm −1 , diamond): 2958 w, 2921 sh, 2870 m (sp3 C—H), 2151 m, (Si—H), 1258 m (sp3 C—H), 1089 s, 1029 s (Si—O—Si).
The product was dissolved in toluene (20 mL), DME (20 mL) and water (142 mL, 142 g, 7.9 moles) and heated at 100 C for 2 h. Then the volatiles are removed by vacuum transfer using a supplementary trap cooled with dry ice/ethanol overnight. To facilitate drying the product, a clear almost colorless oil was slowly stirred, while placed under vacuum while directly attached to a high vacuum line overnight. The product was maintained under vacuum until a pressure of <20 mtorr had been attained overnight. 1 H NMR (CDCl 3 , δ): 0.05 to 0.60 (m, 36H, SiMe), 0.60 to 0.85 (m, 12H, SiCH 2 CH 2 ), 1.40 to 1.90 (m, 18H, SiCH 2 CH 2 CH 2 O, SiCH 2 CH 2 CH 2 CH), 2.15 to 2.85 (m, 9H, CH 2 CH(CO 2 H)CH 2 CO 2 H), 3.15 to 3.75 (m, 51H, CH 2 (OCH 2 CH 2 )OCH 3 ) 9 to 11 (broad m, 6H, CO 2 H). IR (cm −1 , diamond): 2958 sh, 2929 sh, 2874 m (sp3 C—H), 1709 s, (carboxylic acid C═O), 1858 m, (sp3 C—H), 1082 s, 1019 s (Si—O—Si).
Example 11
Preparation of PSAW-Si(R) 3
The preparation of PSAW-Si(R) 3 is described in FIG. 5 , and follows the procedure for preparation of PSAW described in Example 1 using triethyl(octadec-1-en-9-yl)silane in place of octadecene.
Example 12
Preparation of PS2AW
The preparation of polymeric silicone di-amine (PS2AW) follows the synthesis of PS2CAW above in Example 7, using allyl dimethyl succinate to modify the siloxane (see FIG. 8 ). Allyl dimethyl maleate and allyl dimethyl itaconate can also be used. After conjugation to the siloxane polymer via hydrosilylation using a catalyst such as Karstedt's catalyst, Speier's catalyst or Pt(acac) 2 , the esters can be reacted with 1,2-diaminoethane to form the desired product.
Example 13
Preparation of OS2AW
The preparation of oligomeric silicone di-amine (OS2AW) follows the procedure described above in Example 9, using allyl dimethyl succinate to modify the siloxane (see FIG. 7 ). After conjugation to the siloxane polymer via hydrosilylation using a catalyst such as Karstedt's catalyst, Speier's catalyst or Pt(acac) 2 , the esters can be reacted with 1,2-diaminoethane to form the desired product.
Example 14
Preparation of PS3CAW
The preparation of polymeric silicone tricarboxylic acid (PS3CAW) is described below and follows the procedure above in Example 7. The commercially available starting material is triethyl citrate from Aldrich. The alcohol group can be converted to a tosylate leaving group by p-toluene sulfonyl chloride using known methods. Then the tosyl leaving group can be displaced with the allyl alkoxide to form a terminal olefin as shown below.
The allyl modified tris-ester can then be reacted with the siloxane polymer 2 from Example 7 via hydrosilylation with a suitable catalyst such as Karstedt's catalyst, Speier's catalyst or Pt(acac) 2 , to form the siloxane monomer. The final polymer can then be prepared by saponification of the esters, such as via lipase enzyme.
Example 15
Preparation of OS3CAW
The preparation of oligomeric silicone tricarboxylic acid (OS3CAW) is described below.
The commercially available starting material is triethyl citrate from Aldrich. The alcohol functionality is converted to a tosylate leaving group by p-toluene sulfonyl chloride. Then the tosyl leaving group can be displaced with the allyl alkoxide to form a terminal olefin as shown below.
The allyl modified tris-ester can then be reacted with diethoxyoctadecylsilane via hydrosilylation with a suitable catalyst such as Karstedt's catalyst, Speier's catalyst or Pt(acac) 2 , to form the siloxane monomer:
The final polymer can then be prepared by condensation of the siloxane monomer to form the polymer and then saponification of the esters, such as via lipase enzyme:
Example 16
Laser HALT Accelerated Lifetime Test
Nanocrystal compositions with PSAW-1:1 were prepared as described above.
Preparation of Comparative Nanocrystal/Silicone Composition
Another exemplary composite was produced, this one having CdSe/CdS/ZnS nanocrystals in a matrix formed from pendant amine functional silicones. Separate batches of red and green CdSe/CdS/ZnS nanocrystals dissolved in toluene (two batches with different sizes and emission peaks for each color) were exchanged with amino silicone (50:50 mixture of degassed AMS-242 and AMS-233, Gelest, Inc.) at 50° C. for about 66 h. Nanocrystal concentration was between about 3 and 50 OD in toluene, with the amino silicone at 0.01-0.1 ml per ml toluene. The solutions were then cooled to 30° C. and the volatiles removed to p<60 mtorr for about 90 min. Samples were dissolved in toluene at 25 mg (nanocrystals plus amino silicone)/mL. The OD/g (at 1 cm path length) was determined for each batch of red and green nanocrystals at 460 nm using a UV-Vis instrument. The neat solution was calculated by assuming the density of neat nanocrystals in aminosilicone was 1 (i.e., multiplied by 40), to ensure the ODs measured were close to the projected values. Then nanocrystals from the two batches of red and two of green nanocrystals in amino silicone were combined, along with additional amino silicone. The amount of red nanocrystals added from the two red batches was adjusted to obtain a final OD of about 10, and the amount of green nanocrystals added from the two green batches was adjusted to obtain a final OD of about 30. In this example, 6.8 mL of each batch of green nanocrystals and 2.5 mL of each batch of red nanocrystals were combined, along with an additional 11.49 g of the amino silicone (again a 50:50 mixture of degassed AMS-242 and AMS-233). An equal volume of toluene (30 mL) was also added. Ligand exchange was performed on the mixture at 60° C. for 16 h. After heating the mixture was cooled to 30° C. and the volatiles removed to p<35 mtorr for 2 h. After volatiles removal the product was an orange paste.
Preparation of Matrix
0.5 g of the QD/aminosilicone or QD/PSAW composition was then added to 9.5 g of uncured Loctite E-30cl epoxy in a 10 ml plastic cup. The cup was then placed in a a planetary mixer (THINKY ARV-310) and run for 4 minutes at 2000 rpm until homogeneous. The cup was then brought into a glove box. The contents were poured onto a 50 um thick polyester film (3M, Ultrabarrier). A second piece of film was placed on top of the epoxy pool and then the stack was passed through a set of precision rolls to squeeze it down so that the epoxy/quantum dot layer was 100 um in thickness. The stack was then placed in a 100 C oven for 15 min to cure the epoxy.
Laser Procedure.
From the film cast above, a 20 mm diameter is cut using a steel punch. The sample is then clamped between two sapphire plates and mounted into the beam path. The sapphires are coupled to a heating element and maintained at a temperature of 60+/−5° C. The blue laser (450 nm) is attenuated to 60 W/cm2 and has a spot size of approximately 1 mm. A shutter is opened and the beam passes through the film sample. The resulting emission spectra are collected continuously using a spectrophotometer (Ocean Optics, Inc.) with a fiber optic probe. FIG. 4 plots the red and green emission from the film sample as a function of time. Table 2 summarizes the emission data for the films.
TABLE 2
Laser HALT Lifetime Study Data
85%
50%
85%
50%
Lifetime/POR
Lifetime/POR
Lifetime
Lifetime
Temp.
Flux
Standard
Standard
(hrs)
(hrs)
Sample
(° C.)
(W/cm 2 )
Green
Red
Green
Red
Green
Red
Green
Red
ESH
57
60
1.0
1.0
1.0
1.0
1.2
1.8
5.0
6.8
standard
PSAW-1:1
62
60
5.9
5.6
3.6
3.2
7.1
10.2
17.9
21.6
Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, one of skill in the art will appreciate that certain changes and modifications may be practiced within the scope of the appended claims. In addition, each reference provided herein is incorporated by reference in its entirety to the same extent as if each reference was individually incorporated by reference. Where a conflict exists between the instant application and a reference provided herein, the instant application shall dominate. | Siloxane polymer ligands for binding to quantum dots are provided. The polymers include a multiplicity of amine or carboxy binding ligands in combination with long-alkyl chains providing improved stability for the ligated quantum dots. The ligands and coated nanostructures of the present invention are useful for close packed nanostructure compositions, which can have improved quantum confinement and/or reduced cross-talk between nano structures. | 2 |
BACKGROUND OF THE INVENTION
[0001] During conventional fabrication of textile feedstock, especially of cotton pressed in bales, numerous health, technical and economic problems often arise.
[0002] These problems include the development of health threatening molds, especially aflatoxines in the leaves (bracts); insufficient moisture for subsequent treatment steps; and wild behavior of the delivered material in the processing machine or gin before subsequent treatment depending on the quality of the cotton gin, its previous storage condition, press condition and moisture content.
[0003] Attempts to pretreat the feedstock to address the problems have been unsuccessful for technical and/or economic reasons.
[0004] It is therefore a purpose of the present invention to provide a process to solve health and technical problems which have affected prior art textile feedstock fabrication processes.
[0005] It is a further purpose of the invention to provide a process which allows an improvement in the quality of the spun yarn, with a raised yield.
[0006] Yet a further purpose of the present invention is to provide a feedstock preparation method which is reproducible, efficient, and which produces a feedstock which is greatly restricted in its biological activity, especially insuring that only a minimal further development of mold fungi can occur, even in the case of a new contamination occurring by means of airborne spores.
BRIEF DESCRIPTION OF THE INVENTION
[0007] The foregoing and other objects of the invention are achieved by a heat treatment of the feedstock in a pressed state, i.e. in the bale. By a specific, gradual heat treatment of the bale at least partial sterilization and a conditioning of the feedstock is effected simultaneously.
[0008] The heat treatment of the present invention comprises placing the feedstock in a treatment chamber and subjecting the feedstock to a plurality of treatment cycles comprising the evacuation of the chamber to a reduced pressure, and the application of steam to the feedstock for a treatment period to allow the steam to penetrate into the interior of the bale. At least 4, and preferably 5 treatment cycles are conducted.
[0009] The heat treatment can be accomplished by a type of fractional conditioning (alternating evacuation and steaming with holding times) which may be carried out by conventional treating systems as marketed by Xorella AG, CH-5430 Wettingen, Switzerland under the trademark SYSTEM CONTEXOR.
[0010] It has been surprisingly found that the present invention makes it possible to successfully treat a heavily pressed cotton bale in an economically reasonable time with an economically justifiable expenditure of energy. The treatment installation is preferably operated according to WO 98/21390 and U.S. Pat. No. 6,094,840.
[0011] It has been found that a 5 cycle steaming procedure yields an ultimate temperature of about 80° C. in the inner part of the bale. Higher bale temperatures may be desired or utilized when required for sterilization or destruction of biologically active material.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] A fuller understanding of the invention will be achieved upon consideration of the following description of the invention when considered in connection with the annexed drawings, in which:
[0013] [0013]FIGS. 1 a - c are diagrams depicting the structure and placement of temperature probes in a cotton bale for test purposes.
DETAILED DESCRIPTION OF THE INVENTION
[0014] It is known in the art that the conditioning of textile feedstocks, and particularly by conditioning by steam treatments, improve the process ability and quality of the resulting fabric. Conditioned knitting yarns exhibit reduced unwinding tension and are of a softer quality than untreated yarn, reducing needle wear. Further, consistency of the finished products is improved with a substantial decrease in lint and fiber fly. Weaving processes utilizing yarns which have been subject to such conditioning have fewer breaks, improved strength and elongation qualities, and yield softer fabrics. Similarly, treated fabrics experience increased sewing efficiency with fewer needles breaks and improved needle wear. While conventional conditioning treatments are applied to the yarns and threads, the present invention provides an improved methodology for such general heat treatment, and is of particular benefit in connection with cotton, which in accordance with the invention may be treated in the bale, rather than in the form of yarn or finished fabric, thus increasing treatment efficiency. By applying a repeated procedure of evacuation and steam application treatment through the entirety of the bale can be effected in an economical manner.
[0015] In general, the present procedure comprises placing the cotton bale to be treated in a closed container, and evacuating the container to a reduced pressure in the range of about 50 to 200 mbar. Steam is then introduced, and the steam is allowed to permeate the bale for a treatment period typically between 5 and 15 minutes, during which steaming step the internal temperature of the bale increases to roughly between 60° and 80° C. The container is again evacuated, the remaining steam being simultaneously withdrawn and condensed exterior to the container, and the procedure is repeated. Preferably, the fabric is subjected to a minimum of 4 steaming cycles. The the end of the treatment the cotton bale is removed. After an appropriate cool-down period, during which time a small amount of residual moisture evaporates, the bale can be wrapped for shipment.
[0016] Each steam treatment step may be of a chosen duration, on the order of 5 minutes, which typically allows the interior of the bale to reach between 60° and 80° C., the bale temperature increasing with each steaming cycle. A final interior temperature of 80° C. is preferred to insure extermination or elimination of bacteria and/or mold. Temperature monitoring of the bale may be conducted using temperature sensor probes, with the treatment step time being dictated by the interior bale temperature desired. Similarly, the vacuum employed may be at levels of between about 50 and 200 mbar, with the greatest vacuum typically being applied in the initial treatment step. Vacuums of 50, 200, 2000 and 200 mbar for a five cycle process may be acceptable, the vacuum serving primarily to facilitate the entry of the steam deep into the bale and thus improving heat transfer between the steam and bale. Overall process time, including treatment steps and the time necessary to re-evacuate the chamber between treatment steps, is in the order of less than 2 hours.
[0017] The procedure may be carried out in a vacuum steamer chamber of the type known in the art having an internally located water bath which is heated to generate the steam. Alternatively, the steam can be generated exterior to the chamber and introduced to the evacuated chamber through appropriate valved piping. Vacuum pumps and condensers as known in the art establish the vacuum and exhaust the remaining water vapor/steam at the end of a steaming cycle. When an external steam source is used, as opposed to a heated water bath, it may be advantageous to have a drain to allow condensate to be withdrawn before or during vacuum establishment.
[0018] The following sets forth a series of tests carried out in accordance with the invention and are exemplary of the parameters which may be employed in connection therewith.
[0019] A bale having the dimensions 1380×530×900 mm, a volume V=660 cm 3 , weight G approx. 250 kg and a density y=0.38 kg/dm 3 was subjected to a treatment in accordance with the present invention. Temperature probes were inserted at different locations within the bale as depicted in FIGS. 1 a - 1 c. A Xorella CONTEXXOR treatment unit with a volume of 10.2 m 3 was utilized for the treatment process.
[0020] The bale was subjected to a steaming/evacuation program with four vacuum cycles, as follows:
Steaming program 1st vacuum: 050 mbar = 95% 1st cycle: T1 = 600° C. - 5 min. Start 1st cycle with empty evaporator, or with cold water bath. 2nd vacuum: 100 mbar = 90% 2 nd cycle: T2 = 70° C. - 5 min. 3rd vacuum. 100 mbar = 90% 3 rd cycle: T3 = 80° C. - 10 min 4th vacuum: 200 mbar = 80% 4 th cycle: T4 = 80° C. - 15 min. Total time: approx. 100 minutes
[0021] Weight Increase of Bale with 4 Measuring Probes and Pallet:
[0022] Before conditioning: 258.60 kg=100% weight
[0023] 05 minutes after conditioning: 268.90 kg=+3.98% weight increase.
[0024] 90 minutes after conditioning: 267.40 kg=+3.40% weight increase.
Weight of measuring probes 1.25 kg. Weight of pallet: 14.35 kg.
[0025] After a cooling time of 90 minutes, the measuring probes were removed and the bale was wrapped in foil with a pallet binder. In practice it takes about 1-1½ hours before the bales can be packed. A weight increase of 3.0% to a maximum of about 3.2% can therefore be expected.
[0026] Notes on Test Procedure
[0027] The test was erroneously carried out in 2 phases, because on startup and after the first cycle the CPU failed due to software intervention with the programming unit. After the first cycle (96%, 60° C.-5 min) and after reaching the first intermediate vacuum, the program stopped when the heating was switched on, and the evaporator was vented. The process was then restarted. The process was restarted after correcting the above-mentioned fault. And the program ran according to the pre-selected process steps. In general, phase 1 had no effect on the test parameters. This test can be evaluated as a normal steam program with 4 cycles with a prior warm-up program.
[0028] Vacuum
[0029] The startup vacuum of 50 mbar=95% of the vacuum was generated with a gas jet at the vacuum pump intake. The gas jet was not switched on until vacuum had reached 90%.
[0030] The intermediate vacuum up to 100 mbar was generated with a tube bank condenser at the vacuum pump intake.
[0031] Measuring point MP1 reached the setpoint temperature T1=60° C. after the first cycle, and followed the pre-selected temperatures in the subsequent cycles. Steam penetration to a depth of 100 mm occurred by the end of the first cycle.
[0032] Temperatures at depths of 150 and 200 mm respectively for MP 2 and MP 3 started to rise significantly during the warm-up phase of the second vacuum cycle to the setpoint temperature T2=70° C., although the setpoint temperatures was not yet reached. The MP2 setpoint temperature T=80° C. at the 150 mm depth was not reached until the holding phase of the third vacuum cycle.
[0033] The MP 3 setpoint temperature T=80° C. at the 200 mm depth was reached during the fourth vacuum cycle. By this time steam had penetrated the bale to a depth of about 200 mm.
[0034] The temperature rise at MP 4 inside the bale was slow. The temperature rose at 0.75° C. per minute on average. However, the temperature rise was steeper after the end of each vacuum cycle, indicating that steam penetration is accelerated by the intermediate vacuum.
[0035] The setpoint temperature at measuring point MP 4 was reached 10 minutes after reaching the fourth cycle temperature.
[0036] Steam penetration is theoretically complete after reaching the setpoint temperature T4=80° C. inside the bale. Further steaming time does not increase humidity since the entire bale is then heated up to a temperature of 80° C.
[0037] Weight Loss After Packaging
[0038] After a cooling time of 90 minutes, the measuring probes were removed and the bale was wrapped in foil with a pallet binder for storage. The temperature inside the bale was still high at this time, as shown by the following readings:
Measuring point MP 1: 70° C. Measuring point MP 2: 76° C. Measuring points MP 3, 4: 78° C.
[0039] Weight Loss of Packaged Bale No.1 Including Pallet
Days Weight w/pallet Difference Start 267.45 kg (100%) 2 267.30 kg 0.15 kg = 0.00% 4 267.15 kg 0.30 kg = 0.11% 8 266.90 kg 0.55 kg = 0.20% 13 266.65 kg 0.80 kg = 0.30% 21 266.65 kg 0.80 kg = 0.30% 26 266.70 kg 0.75 kg = 0.30%
[0040] Weight loss of the packaged bale after 2 weeks of storage was 0.3% referred to the original weight of 267.45 kg. No weight change occurred during the following week.
[0041] Assuming that the wrapping foil is impermeable to air, no further weight losses are expected. The above-mentioned weight loss of 0.80 kg also includes that of the timber pallet weighing about 15 kg. Steaming increased the pallet weight by about 4% due to 0.60 kg additional water content, which evaporates during storage.
[0042] If this pallet weight loss of about 0.60 kg is deducted from the total weight loss, weight loss attributable to the foil is practically negligible at only 0.20 kg or 0.075%.
[0043] Condensate Accumulation
[0044] After 2 hours of cooling time a condensate film is formed inside the packaging foil, which about 2 days later had consolidated into water drops. These water drops were still clearly visible two days later, but they were no longer visible when the weight measurement was taken 8 days after packaging.
[0045] The cotton bales cooled down within about 4 days, when evaporation ceased and the cotton bales reabsorbed the condensate drops. Cotton can absorb up to about 15% of its own weight in moisture at 100% air humidity.
[0046] Steam penetration can be accelerated by increasing the temperature as rapidly as possible to the setpoint value of about 80° C. after reaching 100 mbar vacuum. Since steam has a vapor saturation pressure of about 450 mbar at 80° C., the pressure differential is then 450−100=350 mbar; this helps to force steam into the bale more efficiently and rapidly.
[0047] Theoretical Considerations
[0048] The weight increase after steaming was 3.98%. This fact alone establishes that 100% of the bale mass was heated up by steaming.
[0049] The theoretical weight increase is calculated as follows based on the given data:
Net weight of bale: G = 250.00 kg Specific heat of cotton: c = 1.3 kl/kg° C. Temperature differential: ΔT = 80°-20° = 60°C. Vaporization heat of steam: r = 2350 kJ/kg steam
[0050] Thermal energy Q required for cotton bale heating to 80° C.:
Q=c×G×ΔT
Q=1.3×250×60=19,500 kJ
[0051] The bale is heated with saturated steam. The steam transfers its vaporization heat to the cotton through condensation Cotton is hygroscopic and can store up to 18% by weight of moisture at 20° C. Since the cotton absorbs the condensate, its weight increases according to the amount of steam required.
[0052] With an evaporation heat of r=2309 kJ per kg steam, the following steam quantity D is required:
D=Q/r
D= 19,500/2350=8.29 kg steam
[0053] 8.29 kg of steam is therefore required to heat the cotton bale to 80° C. The steam then condenses into 8.29 kg of water, which is absorbed by the cotton. This weight increase of 8.29 kg corresponds to a 3.32% increase.
[0054] Since the above calculation does not take into account the original moisture content of about 6%, the actual weight increase is about 13% more than calculated, i.e. about 3.75%. The difference between this figure and the measured weight increase of 3.93%—which is greater than theoretically calculated—is attributable to weighing precision of the balance of +/−0.2 kg and of the physical data
[0055] In a second test in accordance with the invention, a S-cycle procedure was performed on a bale under the following conditions:
Steaming program: 1 st vacuum: 50 mbar = 95% 1st cycle: T1 = 80° C. - 2 min Start 1st cycle with empty evaporator, or with cold waterbath. 2 nd vacuum: 200 mbar = 80% 2 nd cycle: T2 = 80° C. - 5 min 3 rd vacuum: 200 mbar = 80% 3 rd cycle: T3 = 80° C. - 5 min 4 th vacuum: 200 mbar = 80% 4 th cycle: T4 = 80° C. - 7 min 5 th vacuum: 200 mbar = 80% 5 th cycle: T5 = 80° C. - 9 min Total time: approx. 100 minutes.
[0056] Weight Increase of Bale Measuring Probes and with Pallet:
Before conditioning: 260.80 kg = 100% weight 5 minutes after conditioning: 270.15 kg = 3.58% weight increase.
[0057] After about 10 minutes the bale, probes and pallet were wrapped in foil.
[0058] Cooling of the Wrapped Bale
[0059] [0059]FIG. 3 is a plot of the probe temperatures. The cooling temperature readings were as follows:
After 1 day: MP 2, 3, 4 interior 50° C. MP 1 exterior 45° C.
[0060] Notes on Test Procedure
[0061] Control System
[0062] On OP 5 a 1-cycle program was programmed with T=80° C. for 99 minutes. During the holding time of 99 minutes the vacuum pump was switched on and off manually. The holding time for each cycle was maintained until it was clearly established that the temperatures at measuring points 1 to 4 either changed or remained unchanged.
[0063] Vacuum
[0064] Startup Vacuum—50 mbar
[0065] The startup vacuum of 50 mbar=95% was generated with a gas jet at the vacuum pump intake. The gas jet was not switched on until vacuum had reached 90%. The time required to reach the correct vacuum with cold water bath was rather long at 15 minutes. According to calculation (t=60×V/S×In p1/p2=60×10,2/400×3=5), the vacuum should be attained within about 5 minutes. With a cooling water temperature of 15° C. and dry air extraction, vacuum pump operating conditions were optimal. The long time required may be attributable to evaporator leakage or to vacuum pump power deficiency.
[0066] Intermediate Vacuum—200 mbar
[0067] The intermediate vacuum up to 200 mbar was generated with a tube bank condenser at the vacuum pump intake. The first 2 vacuums after the 1st and 2nd cycles lasted 7 minutes, and 8-9 minutes after the 3rd and 4th cycles. The reason for this longer vacuum time after cycles 3 and 4 was that part of the bale mass had already been heated up after the 3rd cycle and had to be cooled down again during the vacuum phase.
[0068] Measuring Point Temperature Sequence
[0069] Temperatures at the 4 measuring points were recorded during the process.
[0070] Measuring Point MP 1: depth 100 mm (black)
[0071] The temperature at this point did not begin to rise until the 2 nd cycle heating and holding phase. It reached the setpoint value at the beginning of the 3 rd cycle.
[0072] Measuring Point MP 2: depth 150 mm (green)
[0073] The temperature at this point did not begin to rise until the 3rd cycle heating and holding phase. It then rose in parallel with the steam temperature, but only reached the setpomnt temperature at the beginning of the 5 th cycle heating phase. During the 4 th cycle holding phase the temperature no longer rose and remained constant. Extending the holding time would therefore have been pointless since the temperature would not have increased any further.
[0074] Measuring Point MP 3: depth 200 mm (blue)
[0075] This temperature characteristic was similar to that at MP 2, but at rather lower temperature level. The setpoint temperature was reached together with MP 2 at the beginning of the 5 th cycle heating phase.
[0076] The temperature characteristics at MP 2 and MP 3 clearly show that 4 cycles are not enough: the fifth cycle is essential. The 4 th cycle holding time can however be shortened from 7 to 5 or even 3 minutes.
[0077] Measuring Point MP 4; depth 250 mm (brown)
[0078] As in test No. 1, the temperature at MP 4 inside the bale rose only slowly at approx. 0.75° C. per minute. The setpoint temperature was not reached until during the 5 th cycle holding time. Here again, the temperature rise was steeper after the end of each cycle.
[0079] Weight Loss After Packaging
[0080] After a short cooling time of only 10 minutes the bale was wrapped with the four probes inserted in order to record the temperature characteristics on cool down. See comments on “Bale weight increase”.
[0081] The total weight of the wrapped bale including probes and pallet on the steaming day was 271.35 kg. The probes (weight 1.25 kg) were removed after temperature measurements 6 days later. The starting weight (100% reference for weight loss measurements) was: 271.35 kg−1.25 kg=270.10 kg
[0082] Weight Loss of Packaged Bale No.3 Including Pallet
Day Weight with pallet Difference Start 270.10 kg None (100%) 6 269.15 kg 0.95 kg = 0.35% 12 269.10 kg 1.00 kg = 0.37%
[0083] The percentage weight loss of 0.37% after 12 days was 0.07% more, or 20% higher than in test No. 1. So even after 12 days, the percentage weight loss was still about 0.3%. This large difference may be attributable to a lower quality packaging with stretch-foil, or to weighing inaccuracy. It can also be due to higher vapor diffusion through the foil with excessively warm packing in the case of bale No. 3.
[0084] If the 0.60 kg pallet weight is deducted as with test No. 1, the weight loss after 12 days is 0.40 kg or 0.15%.
[0085] Condensation Inside the Packaging Foil
[0086] Condensate formed inside the foil and was re-absorbed by the cotton fibers within 5 to 6 days.
[0087] In order to reach steaming temperature as quickly as possible, direct steam injection is preferred. At T=80° C. the vapor pressure is about 500 mbar, so that steam is forced into the bale by a pressure differential of 300 mbar over the previous 200 mbar vacuum.
[0088] Direct steam injection can eliminate the problem of water batch contamination by cotton fibers.
[0089] At least four cycles are required. With adequate heating capacity, it should be possible to complete the process in no more than 2 hours.
[0090] Energy Consumption per Tonne of Cotton Fiber—approx. 45 kWh
[0091] The theoretical energy consumption per tonne of yarn with temperature rise A T=60° C. is 1.3×1000×60=78,000 kJ=22kWh. Taking into account the 4 to 5 reheatings—required after the intermediate cycles, each time by about 20° C., as well as other losses, about 100% additional energy is required. In general we should expect here an optimistic energy consumption of about 45 kWh per tonne of yarn. | A heat treatment process for fiber feedstock, such as cotton in the baled form, comprises repeatedly subjecting the bale to a reduced pressure atmosphere followed by the introduction of steam which permeates the bale. The interior of the bale may ultimately reach a temperature of about 80° C., which conditions and sanitizes the cotton fibers. Reduced pressure in the range of 20-200 mbar and steam treatment time in the order of 5 minutes can be employed. | 3 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to centrifugal turbo-machines and, more particularly, to a centrifugal turbo-machine in which an axial thrust control member is configured to automatically control axial thrust generated by a difference between static pressures of front and rear ends of an impeller provided in a centrifugal pump or compressor, thus appropriately controlling axial thrust even if the axial thrust varies attributable to abnormal operation conditions.
[0003] 2. Description of the Related Art
[0004] Generally, a centrifugal turbo-machine is a machine which applies kinetic energy (dynamic pressure) to fluid using reaction induced by rotation of an impeller and converts it into pressure energy (static pressure). A centrifugal pump, a centrifugal compressor or the like is a representative example of the centrifugal turbo-machine.
[0005] FIG. 1 is a sectional view showing the construction of a centrifugal turbo-machine 10 according to a conventional technique.
[0006] Referring to FIG. 1 , the conventional centrifugal turbo-machine 10 which converts kinetic energy applied to fluid into pressure energy includes a rotating shaft 12 , an impeller 13 , a volute casing 11 and seals 14 and 15 . The rotating shaft 12 is rotatably installed in the volute casing 11 and supported by a bearing 16 .
[0007] The impeller 13 is fastened to the rotating shaft 12 and rotates along with the rotating shaft 12 . The impeller 13 draws fluid using centrifugal force generated by rotation thereof.
[0008] The volute casing 11 defines therein a space into which fluid drawn by the impeller 13 flows. In the volute casing 11 , dynamic pressure of drawn fluid is converted into static pressure. In other words, in the volute casing 11 , kinetic energy of drawn fluid is converted into pressure energy.
[0009] The seals 14 and 15 reduce the amount of leakage of drawn fluid to increase the efficiency of the centrifugal turbo-machine 10 . The seals 14 and 15 are positioned corresponding to the front and rear ends of the impeller 13 .
[0010] The operation of the conventional centrifugal turbo-machine 10 having the above-mentioned construction will be explained below.
[0011] The impeller 13 rotates in the hermetically sealed volute casing 11 to draw fluid into the volute casing 11 . Then, centrifugal force is generated by the impeller 13 . Fluid is drawn into the volute casing 11 by the centrifugal force of the impeller 13 . While the drawn fluid flows into the volute casing 11 , dynamic pressure of fluid is converted into static pressure in the volute casing 11 , thus producing pressure energy.
[0012] However, some of fluid drawn by the impeller 13 flows through gaps between the surface of the impeller 13 and the seals 14 and 15 rather than being drawn into the volute casing 11 . Fluid passing through the gaps defined by the seals 14 and 15 differ in pressure from each other, thus generating axial thrust.
[0013] As shown in FIG. 1 , the shapes of the front and rear ends of the impeller 13 differ from each other and the area of the gap between each end of the impeller 13 and its surrounding casing also have difference. Thus, pressures formed around the front and rear ends of the impeller 13 differ from each other. Furthermore, pressures around outlets of the seals 14 and 15 differ from each other. Therefore, axial thrust is generated in a direction from the rear end of the impeller 13 towards the front end thereof.
[0014] This axial thrust is applied to the rotating shaft 12 of the centrifugal turbo-machine 10 . The force applied to the rotating shaft 12 is supported by the bearing 16 coupled to the impeller 13 .
[0015] Here, in the case where appropriate intensity of axial thrust is applied to the rotating shaft 12 , the bearing 16 can reliably support the rotating shaft 12 . However, if excessive axial thrust is applied to the rotating shaft 12 , the expected lifetime of the bearing 16 is reduced. If it exceeds a limit, the bearing 16 may be damaged.
[0016] Therefore, to prevent damage of the turbo-machine 10 and increase the lifetime of the bearing 16 , the axial thrust should be successfully controlled. For this, a difference between static pressures applied to the front and rear ends of the impeller 13 must be reduced.
[0017] In the conventional technique, to reduce a difference between static pressures applied to the front and rear ends of the impeller 13 , the area of gap between the impeller 13 and the volute casing 11 was changed by varying the diameters of the seals 14 and 15 provided around the front and rear ends of the impeller 13 .
[0018] In detail, the conventional technique has used a method in which the intensity of axial thrust generated around the rear end of the impeller 13 is reduced by increasing the diameter of the seal 15 provided around the rear end of the impeller 13 which typically generates relatively large axial thrust. However, the method of reducing axial thrust by changing the diameter of the seal 15 requires much time and costs in manufacturing the turbo-machine, so that it is not economic.
[0019] Recently, in an effort to overcome the above problem of poor economy, a method of installing an axial thrust control member for controlling axial thrust in a turbo-machine has been developed.
[0020] FIG. 2 is a sectional view showing a turbo-machine 20 having an axial thrust control member 30 according to a conventional technique.
[0021] Referring to FIG. 2 , the turbo-machine 20 having the axial thrust control member 30 can more economically control axial thrust, compared to the prior method of changing the diameter of the seal. However, if input values different from the input values it was designed for are applied to the turbo-machine 20 while it is being operated, an operational problem may be induced. Furthermore, there is a disadvantage in that the turbo-machine 20 may not be able to resist abnormal operation circumstances.
[0022] For example, in the case where a flow rate of fluid drawn into the turbo-machine 20 is less than the flow rate it was designed for, output pressure is increased and a pressure around the impeller 23 is also increased. Thereby, the entire axial thrust applied to the turbo-machine 20 is also increased.
[0023] Furthermore, if a design of a fluid supply system for operating the turbo-machine 20 is not appropriate or a loss of pressure of the fluid supply system is increased by penetration of foreign substances while the turbo-machine 20 is being operated, a flow rate of fluid drawn into the turbo-machine 20 becomes less than the designed flow rate and the axial thrust applied to the turbo machine 20 is increased.
[0024] In addition, in the case where the design of the impeller 23 or the volute casing 21 does not correspond to the designed flow rate, there is a probability of an increase in output pressure. This also is a factor of an increase in axial thrust.
[0025] Moreover, the axial thrust control member 30 cannot automatically control axial thrust while the turbo-machine 20 is being operated. Merely, the height of the rib 31 of the axial thrust control member 30 is determined to a degree capable of reducing axial thrust in consideration of the intensity of axial thrust expected to be generated while the turbo-machine 20 is being operated. Then, pressure of fluid drawn through the rear end of the impeller 23 is reduced by the resistant force of the rib 31 , thus controlling axial thrust.
[0026] However, to effectively use the axial thrust control member, after a design flow rate of the turbo-machine 20 and output axial thrust are correctly checked, can the turbo-machine 20 be operated. Only then can the generation of expected axial thrust be appropriately controlled.
[0027] Furthermore, a problem in an increase of axial thrust exceeding an expected value because of the above several reasons cannot be controlled by the axial thrust control member 30 . In this case, in the same manner as the prior turbo-machine 10 having no axial thrust control member, the bearing 26 may be damaged with the result that the lifetime of the turbo-machine is reduced.
[0028] As such, in the conventional turbo-machine, when pressure around the seals 24 and 25 is increased over an expected value, the axial thrust control member 30 cannot exhibit its intended function. To improve this, a precise measure of axial thrust is indispensably conducted before the machine is operated. If unexpected measurement results are produced, the design of the axial thrust control member 30 must be revised, or it must be newly manufactured or installed.
SUMMARY OF THE INVENTION
[0029] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a turbo-machine in which protruding heights of ribs provided on an axial thrust control member are automatically controlled depending on an intensity of pressure of fluid drawn behind a rear end of an impeller, so that even though excessive axial thrust greater than a value expected when designing the turbo-machine is generated, the axial thrust can be automatically controlled.
[0030] In order to accomplish the above object, the present invention provides a turbo-machine, including: a volute casing defining therein a fluid passage for forming a fluid pressure; a rotating shaft provided in the volute casing so as to be rotatable; an impeller coupled to one end of the rotating shaft to draw fluid using centrifugal force generated by rotation; seals provided around front and rear ends of the impeller to prevent leakage of the fluid; an axial thrust control member installed in the volute casing behind the impeller with respect to a flowing direction of the fluid, the axial thrust control member having an annular planar shape, with a plurality of ribs provided on one surface of the axial thrust control member facing the flowing direction of the fluid such that portions of the ribs are exposed from the surface of the axial thrust control member to impede rotation of the fluid; and a bellows unit, having a piston surrounding a circumferential outer surface of the axial thrust control member, the piston covering the outer surface of the ribs and a bellows connected with one surface of the piston, the bellows having a predetermined elasticity.
[0031] The bellows unit is constructed such that the bellows is compressed by pressure of the fluid drawn into the volute casing and the piston automatically moves by a predetermined distance along the axial direction.
[0032] The axial thrust control member may be constructed such that the ribs are further exposed from the axial thrust control member by a distance corresponding to the distance that the piston moves along the axial direction, thus increasing resistant force of the ribs impeding the rotation of the fluid.
[0033] The piston may have a sealing member to isolate the internal space defined by the piston and the volute casing from fluid drawn behind the impeller.
[0034] The bellows unit may be controlled such that a sum of the elastic force of the bellows and a pressure in the internal space is equal to a pressure of the fluid drawn behind the impeller.
[0035] In the bellows unit, when the pressure of the fluid drawn behind the impeller is increased, the bellows may be automatically compressed and the resistant force of the ribs provided on the axial thrust control member is thus increased, so that the increased pressure of the fluid is reduced until the sum of the elastic force of the bellows and the pressure in the internal space is equal to the pressure of the fluid drawn behind the impeller.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
[0037] FIG. 1 is a sectional view showing the construction of a centrifugal turbo-machine according to a conventional technique;
[0038] FIG. 2 is a sectional view showing a turbo-machine having an axial thrust control member, according to another conventional technique;
[0039] FIG. 3 is a sectional view of a turbo-machine having a bellows unit, according to an embodiment of the present invention;
[0040] FIG. 4 is a sectional view illustrating an axial thrust control member according to the embodiment of the present invention;
[0041] FIG. 5 is a sectional and front view illustrating the piston which moves by the elastic force of the bellows and the insert hole which couples with the ribs of the axial thrust control member;
[0042] FIG. 6 is a front view illustrating the construction of the axial thrust control member according to the embodiment of the present invention;
[0043] FIG. 7 is a front view and an enlarged view showing the coupling between the axial thrust control member and the bellows unit according to the embodiment of the present invention;
[0044] FIG. 8 is an enlarged sectional view of the portion A of FIG. 3 when the bellows unit is not in operation according to the embodiment of the present invention;
[0045] FIG. 9 is a view corresponding to the sectional view taken along the line B-B′ of FIG. 7 when the bellows unit is not in operation according to the embodiment of the present invention;
[0046] FIG. 10 is an enlarged sectional view of the portion A of FIG. 3 when the bellows unit is in operation according to the embodiment of the present invention; and
[0047] FIG. 11 is a view corresponding to the sectional view taken along the line B-B′ of FIG. 7 when the bellows unit is in operation according to the embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0048] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings. The terms and words used in the specification and claims must not be limited to typical or dictionary meanings, but must be regarded as concepts selected by the inventor as concepts which best illustrate the present invention, and must be interpreted as having meanings and concepts adapted to the scope and spirit of the present invention to aid in understanding the technology of the present invention.
[0049] Therefore, the construction of the embodiment illustrated in the specification and the drawings must be regarded as only one illustrative example, and these are not intended to limit the present invention. Furthermore, it must be understood that various modifications, additions and substitutions are possible at the point of time of application of the present invention.
[0050] The construction of a turbo-machine having a bellows unit according to the embodiment of the present invention will be described in detail.
[0051] FIG. 3 is a sectional view of the turbo-machine 100 having the bellows unit 200 , according to the embodiment of the present invention. FIG. 8 is an enlarged sectional view of the portion A of FIG. 3 when the bellows unit 200 is not in operation.
[0052] Referring to FIG. 3 and 8 , the turbo-machine 100 according to the embodiment of the present invention includes a volute casing 110 , a rotating shaft 120 , an impeller 130 , seals 140 and 150 , an axial thrust control member 210 and a bellows unit 200 .
[0053] The functions and operation of the volute casing 110 , the rotating shaft 120 , the impeller 130 and the seals 140 and 150 are the same as those of the corresponding elements of the conventional turbo-machine 20 having the turbo-machine 10 and the axial thrust control member, therefore further explanation is deemed unnecessary.
[0054] FIG. 4 is a sectional view of an axial thrust control member 210 according to the embodiment of the present invention. FIG. 5 is a sectional and front view illustrating the piston 213 which moves by the elastic force of the bellows 214 and the insert hole 216 which couples with the ribs of the axial thrust control member 210 . FIG. 6 is a front view illustrating the construction of the axial thrust control member 210 according to the embodiment of the present invention. FIG. 7 is a front view and an enlarged view showing the coupling between the axial thrust control member 210 and the bellows unit 200 .
[0055] Referring to FIGS. 4 through 7 , the axial thrust control member 210 comprises an annular planar member. A plurality of ribs 211 protrudes from one surface of the axial thrust control member 210 which faces the flow of fluid in order to reduce a difference in static pressure between the front and rear ends of the impeller 130 and thus control axial thrust.
[0056] Here, the axial thrust control member 210 reduces an angular velocity component of fluid generated by the rotation of the impeller 130 and thus controls pressure around the rear end of the impeller 130 . The effect of pressure control is determined by the shape of the axial thrust control member 210 .
[0057] Preferably, the height to which each rib 211 protrudes and the number of ribs 211 are determined in consideration of both a flow rate of fluid to be drawn when the turbo-machine 100 is being operated and the intensity of axial thrust to be generated.
[0058] As the height to which each rib 211 protrudes is increased, the extent of decrease in the pressure of fluid to be drawn is increased. As the height to which each rib 211 protrudes is reduced, the extent of decrease in the pressure of fluid to be drawn is also reduced.
[0059] Furthermore, as the number of ribs 211 is increased, the amount of decrease in pressure of fluid to be drawn is increased. As the number of ribs 211 is decreased, the extent of decrease in the pressure of fluid to be drawn is also reduced.
[0060] Meanwhile, the bellows unit 200 includes a piston 213 which has an annular planar shape and surrounds the circumferential outer surface of the axial thrust control member 210 and covers the outer surface of the rib 211 and a bellows 214 which is connected with one surface of the piston and has a predetermined elasticity.
[0061] Furthermore, rib insert holes 216 , the number of which is the same as that of ribs 211 , are formed in one surface of the piston 213 , so that the ends of the ribs 211 which protrude from the axial thrust control member 210 are respectively inserted into the rib insert holes 216 .
[0062] The piston 213 has at edges thereof sealing members 215 a and 215 b which isolate the internal space 217 from the outside such that the pressure of the internal space 217 is maintained at atmospheric pressure.
[0063] As such, the pressure inside the piston 213 , that is, the pressure in the internal space 217 , is maintained at atmospheric pressure. The pressure outside the piston 213 varies depending on the pressure of drawn fluid. Therefore, different pressures are applied to the inside and the outside of the piston 213 .
[0064] With regard to the atmospheric pressure state in the internal space 217 , it is preferable that when the piston 213 is installed in the volute casing 110 , the internal space 217 defined by the piston 213 be sealed in the atmospheric pressure state. However, the present invention is not limited to this. The initial pressure in the internal space 217 may be determined depending on the amount of fluid drawn into the volute casing 110 and the intensity of fluid pressure.
[0065] In the bellows unit 200 , the bellows 214 is compressed by the pressure of fluid drawn into the volute casing 110 so that the piston 213 moves automatically by a predetermined distance.
[0066] Furthermore, the ribs 211 of the axial thrust control member 210 are further exposed at heights corresponding to the distance that the piston 213 moves along the axial direction. Thus, force resistant to rotation of fluid by the impeller 130 is increased by the ribs 211 .
[0067] The operation principle of the turbo-machine 100 having the bellows unit 200 according to the embodiment of the present invention will be described below.
[0068] FIG. 8 is an enlarged sectional view of the portion A of FIG. 3 when the bellows unit 200 is not in operation according to the embodiment of the present invention. FIG. 9 is a view corresponding to the sectional view taken along the line B-B′ of FIG. 7 when the bellows unit 200 is not in operation according to the embodiment of the present invention. FIG. 10 is an enlarged sectional view of the portion A of FIG. 3 when the bellows unit 200 is in operation according to the embodiment of the present invention. FIG. 11 is a view corresponding to the sectional view taken along the line B-B′ of FIG. 7 when the bellows unit 200 is in operation according to the embodiment of the present invention.
[0069] Referring to FIGS. 8 and 9 , when the turbo-machine 100 of the present invention is in operation within expected design parameters, axial thrust generated is controlled in such a way that the ribs 211 exposed from the surface of the axial thrust control member 210 impede rotation of fluid to reduce an angular speed of the fluid, and further so that static pressure of fluid around the rear end of the impeller 130 rapidly reduces.
[0070] Here, in the bellows unit 200 , the bellows 214 and the piston move as shown in FIG. 9 in order that the sum of a pressure P be1 applied to the piston 213 by the bellows 214 and an atmospheric pressure P air formed in the internal space 217 defined by the piston 213 is equilibrated with a pressure P 1 of fluid drawn behind the rear end of the impeller 130 .
[0071] In other words, the bellows unit 200 is constructed such that the sum of the elastic force of the bellows 214 provided in the internal space 217 defined by the piston 213 and the pressure in the internal space 217 is the same as the pressure of fluid drawn behind the rear end of the impeller 130 .
[0072] Meanwhile, in the case where the turbo-machine 100 is operated under unexpected conditions so that the output pressure of the impeller 130 becomes higher than the expected value, as shown in FIGS. 10 and 11 , the pressure P 2 of fluid drawn behind the rear end of the impeller 130 is also increased (P 2′ >P 1 ). Thereby, the piston 213 automatically moves along the axial direction. Thus, the protruding heights of the ribs 211 of the axial thrust control member 210 are relatively increased.
[0073] In other words, when the pressure of fluid drawn behind the rear end of the impeller 130 is increased, the piston 213 of the bellows unit 200 automatically moves. Thus, the resistant force of the ribs 211 of the axial thrust control member 210 is increased and the fluid pressure which has been increased is reduced. Therefore the ribs 211 have been relatively increased in height function to reduce the pressure of fluid behind the seal 150 and prevent excessive axial thrust from being applied to a pump rotor.
[0074] At that time, the bellows 214 is compressed according to the movement of the piston 213 and the elasticity of the bellows increases. Also, the pressure of the internal space 217 increases due to the shrink of the volume.
[0075] Ultimately, the position of the piston 213 is determined as a position at which the pressure of fluid drawn behind the rear end of the impeller 130 is equilibrated with the sum of the elastic force of the bellows 214 and the pressure in the internal space 217 (P 2 =P be2 +P air′ , P 2 <P 2′ ).
[0076] As such, even in unexpected conditions, the turbo-machine 100 can automatically control the axial thrust. Therefore, the present invention can be free from a problem pertaining to the axial thrust which limits the design of the turbo-machine 100 . Furthermore, by virtue of the automatic control of the axial thrust, the lifetime of the bearing 160 of the turbo-machine 100 can be increased.
[0077] As described above, in the turbo-machine according to the present invention, a bellows unit can automatically reduce a difference in static pressure of drawn fluid depending on the intensity of pressure of the fluid. Therefore, the turbo-machine can be more reliably and smoothly operated.
[0078] Furthermore, because axial thrust can be automatically controlled, damage of elements, such as a bearing, etc., can be prevented. Thus, the durability of the turbo-machine can be enhanced.
[0079] Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. | The turbo-machine of the present invention includes a volute casing, a rotating shaft, an impeller, seals, an axial thrust control member and a bellows unit. The volute casing defines therein a fluid passage. The rotating shaft is rotatably provided in the volute casing. The impeller is coupled to the rotating shaft to draw fluid using centrifugal force. The seals are provided around the front and rear ends of the impeller to prevent leakage of fluid. The axial thrust control member is installed in the volute casing behind the impeller. The bellows unit includes the piston installed in the volute casing in a shape surrounding a circumferential outer surface of the axial thrust control member; and a bellows connected with one surface of the piston, the bellows having the predetermined elasticity; and an internal space, between the piston and the volute casing, isolated from the fluid drawn behind the impeller. | 5 |
1. CROSS REFERENCE TO RELATED APPLICATION
The present application is a continuation-in-part of application Ser. No. 07/299,174 filed 01/19/89 by Mustafa Arifoglu and William N. Marmer, entitled "Sequential Oxidative and Reductive Bleaching in a Multicomponent Single Liquor System".
2 FIELD OF THE INVENTION
The present invention relates to processes for oxidative (using hydrogen peroxide) and reductive bleaching of fibers, and fibers bleached by the aforementioned processes.
3. BACKGROUND AND SUMMARY OF THE INVENTION
The occurrence of dark (i.e. pigmented and/or stained) fibers often gives rise to annoying and expensive problems for manufacturers at all stages of fiber processing. For example, extensive literature is available on the occurrence of dark fibers in white wool, see e.g.: Fleet, M. R., Pigmented Fibres in White Wool, Wool Technology and Sheep Breeding 33, 5-13 (1985); Fleet, M. R., Stafford, J. E., Dawson, K. A., and Dolling, C. H. S., Contamination of White Wool by Melanin-pigmented Fibres when Pigmented and White Sheep Graze Together, Aust. J. Exp. Agric. 26, 159-163 (1986); Foulds, R. A., Wong, P., and Andrews, J. W., Dark Fibres and Their Economic Importance, Wool Technology and sheep Breeding 32(2), 91-100 (1984), and; Nolan, C., and Foulds, R., Dark-fibre Contamination in Wool, Queensland Agricultural J. Nov.-Dec., 305-307 (1985). The degree of contamination of white wool by colored fibers has a significant influence on its commercial value, especially when the wool is to be processed into light or pastel-colored articles. The manual removal of dark fibers is an extremely work- and cost- intensive, eye-straining job.
If the contents of dark fibers in white wool are above an acceptable level for white or pastel end uses, then those dark fibers need to be lightened to improve the appearance and to increase the value of the goods (see in this regard Turner, T. R., and Foulds, R. A., Decision Schemes for Assessing Dark Fiber Concentration in Top, Textiles Res. J. 57(12), 710-720 (1987). It is often found that the fibers and sliver of yarn are not tested properly for dark fiber content, and hence these impurities are first seen as dark fibers interwoven into the fabric matrix or in the end product. In such cases the dark fibers have to be removed manually with tweezers. A more convenient and economical alternative is given by the possibility of a wet treatment, which is much more productive and in many cases also less expensive.
The color of dark (i.e. pigmented) fibers ranges from black through shades of brown to light yellow, and the lightening of black fibers needs more severe wet treatment than those of the lighter fibers. Wet treatment conditions, however, should not be so severe as to damage the fibers excessively at the expense of lightening a few black fibers. Therefore, the present invention utilizes a treatment which is selective for areas of high dark fiber content. There have been numerous publications on the bleaching of hair (see e.g. Wolfram, L. J., and Albrecht, L., Chemical and Photo-bleaching of Brown and Red Hair, J. Soc. Cosmet, Chem. 82, 179-191 (1987); Wolfram, L. J., Hall, K., and Hui, I., The Mechanism of Hair Bleaching, J. Soc. Cosmet. Chem. 21, 875-900 (1970), and; Zahn, H., Hilterhaus, S., and Strussman, A., Bleaching and Permanent Waving Aspects of Hair Research, J. Soc. Cosmet. Chem. 37, 159-175 (1986)) and dark wool fibers (see for example, Bereck, A., Bleaching of Dark Fibres in Wool, Proc. 7th. Int. Wool Res. Conf., Tokyo, vol. IV, 152-162 (1985); Bereck, A., and Kaplin, J. J., Electron-microscope Observations on the Disintegration of Melanin Granules in Chemically Treated Karakul Wool, J. Textile Inst. 74, 44-47 (1983); Bereck, A., Zahn, H., and Schwarz, S., Das Selective Bleichen von Pigmentierten Haaren in Rohweisser Wolle, Textil Praxis Int. 37, 621-629 (1982) Finnimore, E., and Bereck, A., Verhalten von selectiv gebleichter Wolle, Melliand Textilberichte 68, 669-672 (English translation, E291-292) (1987); Kriel, W. J., Albertyn, D., and Swanepoel, O. A., Melanin-bleeding of Pigmented Karakul Wool, SAWTRI [South African Wool Textile Research Institute] Bulletin 3(1), 16-20 (1969); Laxer, G., and Whewell, C. S., Some Physical and Chemical Properties of Pigmented Animal Fibres, Proc. Int. Wool Res. Conf. Australia vol. F, 186-200 (1955); Teasdale, D. C., and Bereck, A., The Measurement of the Color of Bleached and Natural Karakul Wool, Textile Res. J. 51, 541-549 (1981), and; Van Heerden, N., Becker, J., van der Merwe, J. P., and Swanepoel, O. A., Bleaching of Karakul Wool, SAWTRI [South African Wool Textile Research Institute] Bulletin 3(4), 21-23 (1969)). Laxer and Whewell, Ibid, first realized that black-brown pigmented fibers absorb iron from ferrous sulfate solutions more rapidly and to a greater extent than white fibers, probably owing to the formation of a metal complex with the melanin of the pigment granules. Union between the iron and the fiber is reasonably firm and this bound iron is a useful catalyst for promoting bleaching when the iron-containing fibers are immersed in solutions of hydrogen peroxide.
All known processes for bleaching pigmented dark fibers are based on the use of peroxy compounds, Bereck (1985), Ibid. Wolfram et al (1970), Ibid, have studied the mechanism of hair bleaching in detail. They found that the bleaching reaction occurs in two steps; the initial solubilization of the granules is followed by the decolorization of the dark brown solubilized pigment. The pigment granules are distributed within the cortex (Laxer, Ibid) and therefore the bleaching of the granules is a diffusion-controlled reaction. Some oxidation of the keratin matrix does occur during the bleaching process due to diffusion. Wolfram et at (1970) Ibid, showed that neither reducing agents such as thioglycolic acid; borohydride, sulfide and sulfite, nor some oxidizing agents such as persulfate, perchlorate, iodate and permanganate, produce any apparent physical change in the melanin pigment. A different behavior was displayed by hydrogen peroxide. Dilute aqueous solutions of this reagent caused disintegration of the pigment granules, which slowly dissolved in the reaction system. The dark brown solution gradually became lighter over a long period of time. The second step (decolorization of the melanin granules) is therefore much slower than the first step (solubilization of the melanin pigment) and hence the former is the rate-determining step in the overall process. It was pointed out that the disintegration process alone is unlikely to affect the color of hair significantly; it may cause only a slight change in hue.
The dissolution of melanin in alkali, observed for example in the "bleeding" of pigmented fibers even at only sightly alkaline pH, is a well-known phenomenon, Kriel et al, Ibid. Bereck and Kaplin, Ibid, have studied the disintegration of melanin granules in chemically treated karakul wool using an electron microscope. Their studies revealed the following interesting features. Under identical bleaching conditions, the destruction of the melanin granules was virtually complete in the mordanted wool whereas in the untreated wool the granules were only partly dissolved. These workers have also observed that the electron micrographs of bleached wool were not unlike those of the samples treated with alkali. However, the change in luminosity due to the alkali treatment was negligible compared with the relatively high luminosity of the bleached wool. This strongly supports the view of Wolfram et al. (1970), Ibid, that melanin disintegration does not significantly influence fiber color. It may be said that the solubilized melanin stains the fibers in the same way as a black dyestuff, Bereck and Kaplin, Ibid. A mixture of hydrogen peroxide and ammonium and/or potassium persulfate has been used successfully in the bleaching of melanin granules, as described in Corbett, J. F., The Chemistry of Hair-care Products, J. Soc. Dyers Colour. 92, 285-303 (1976).
There had been extensive research carried out on the selective bleaching of dark fibers using Bereck's iron mordanting technique (as described in Bereck (1985), Ibid), and the process was adopted successfully by many West German textile mills. This process consists of 3 stages, namely (i) mordanting, (ii) rinsing, and (iii) bleaching. Bereck particularly pointed out the importance of a proper choice of reducing agents in the application of ferrous salts to wool during mordanting and the thorough rinsing of the "loosely bound" ferrous and ferric ions from wool. Of the many reducing agents tested in Bereck (1985), hypophosphorous and phosphorous acids proved to be the best stabilizing agents for minimizing damage to the wool fiber. Giesen and Ziegler in Die Absorption von Eisen durch Wolle und Haar, Melliand Textilberichte, 62, 482-283 (English translation, E622-625) (1981), provide a study of the absorption of iron by wool and hair and concluded that optimum conditions for selective absorption of iron by dark fibers in wool were achieved within a pH range of 3.0-3.5, using a treatment time of 60 minutes at 80° C. Within the pH range mentioned above, the pigmented karakul wool absorbed the greatest amount of iron. At higher pH values, the absorption of iron by pigmented karakul wool diminished as the maximum uptake of iron by nonpigmented merino wool was reached at pH 4.5. Here, it would be disadvantageous to work at pH values greater than 3.5 due to an increase in iron uptake by nonpigmented wool, which may cause extensive damage and discoloration during bleaching.
Even though the aforementioned three-step process may be carefully conducted, there always remains some residual trivalent iron, which tends to give an overall undesirable reddish-brown discoloration or cast to the wool (apparently due to oxidation of ferrous to ferric ions during bleaching). Bereck et al 1982, Ibid, already have shown that selective bleaching hardly alters the natural cream color of wool. However, increasing demand for "bleached white" material led Finnimore and Bereck, Ibid, to investigate the further bleaching of selectively bleached material. Selectively bleached wool was given a second step reductive or oxidative bleaching to yield whiter material.
German Offenlegungsschrift 3,433,926 (3/27/86) to Streit et al discloses a single bath reductive and oxidative bleaching process, in which the reductive bleaching with thiourea dioxide precedes an oxidative hydrogen peroxide bleaching, whereas in the processes of the present invention the reductive bleaching is subsequent to the oxidative bleaching. Japanese patent 51-64082 (6/3/76) is drawn to a reductive bleaching process in which hydrogen peroxide and thiourea are mixed at the start of the bleaching processes (i.e., bleaching with a single mixture which contains both hydrogen peroxide and thiourea), while by contrast the instant invention utilizes separate steps of oxidative bleaching followed by reductive bleaching. It has unexpectedly and surprisingly been discovered that the process of the present invention provides greatly improved results (including, a higher Whiteness Index, lower Yellowness Index, and lower degree of damage) as compared to the results achieved by either of these two prior art processes.
It is a first object of the present invention to provide bleaching greatly superior to that of prior art processes, said bleaching providing fibers which are essentially pigment free, essentially free of iron residue (i.e. without the aforementioned undesirable reddish-brown discoloration or cast) and/or of a surprising and unexpectedly high degree of whiteness, low degree of yellowness and low degree of fiber damage.
It is a second object of the present invention to provide processes which may provide oxidative and reductive bleaching in a single bath, and thereby provide the advantages of: (a) avoiding the two or three step treatment processes normally required by conventional processes, thereby simplifying the process; (b) reducing the amount of time and energy required to provide effective bleaching; and (c) reducing the amount of equipment required to perform the bleaching.
Other objects and advantages of this invention will become readily apparent from the ensuing description.
The aforementioned objects and advantages are achieved by several processes of the instant invention. Two processes of the instant invention which employ mordanting utilize the initial steps of:
bringing both pigmented and unpigmented fibers into contact with ferrous ions under conditions which provide adsorption of the ferrous ions by the pigmented and unpigmented fibers; removing (as for example by rinsing) a portion of the ferrous ions from the pigmented and unpigmented fibers with at least a portion of the ferrous ions remaining on the pigmented fibers, and;
contacting the pigmented and unpigmented fibers with hydrogen peroxide under conditions which provide oxidative bleaching of both the pigmented and unpigmented fibers, including oxidative bleaching of the pigmented fibers by interaction of the hydrogen peroxide with ferrous ions remaining on the pigmented fibers, to produce bleached fibers in contact with unspent hydrogen peroxide. In a first process of the present invention said initial steps are followed by the steps of:
adding to the bleached fibers in contact with unspent hydrogen peroxide a material which combines with hydrogen peroxide to form a reductive bleaching agent in an amount sufficient to produce a reductive bleaching media; and
maintaining the bleached fibers in the reductive bleaching media under conditions providing reductive bleaching of the bleached fibers. In a second process of the present invention said initial steps are followed by the steps of:
adding to the bleached fibers in contact with unspent hydrogen peroxide, an inactivating material in an amount at least sufficient to inactivate all of said unspent hydrogen peroxide to form an inactivated media; and
subsequent to said inactivation of all said unspent hydrogen peroxide, reductively bleaching said bleached fibers by addition of a reductive bleaching agent to said inactivated media.
Additionally the present invention encompasses processes employing hydrogen peroxide and at least one persulfate containing compound, rather than the aforementioned iron-mordanting i.e.: first process which comprises,
contacting fibers with hydrogen peroxide and at least one persulfate containing compound under conditions which provide oxidative bleaching of the fibers to produce bleached fibers in contact with unspent hydrogen peroxide;
adding to the bleached fibers in contact with the unspent hydrogen peroxide (from the previous step, a material which combines with hydrogen peroxide to form reductive bleaching agent (e.g. thiourea, substituted thiourea (e.g. 1,3-dimethyl-2-thiourea, 1,3-diphenyl-2-thiourea, 1,1,3,3,-tetramethyl-2-thiourea), compounds containing thiol (for example, 1-dodecanethiol, 1-octadecanethiol, thioglycolic acid, thiophenol)), in an amount sufficient to produce a reductive bleaching media; and
maintaining the oxidatively bleached fibers in said reductive bleaching media under conditions providing reductive bleaching of the bleached fibers, and;
A second process of the present invention which comprises,
contacting fibers with hydrogen peroxide and at least one persulfate containing compound under conditions which provide oxidative bleaching of the fibers to produce bleached fibers in contact with unspent hydrogen peroxide;
adding to the bleached fibers in contact with unspent hydrogen peroxide (from the previous step-, an inactivating material in an amount at least sufficient to inactivate all of the unspent hydrogen peroxide to form an inactivated media; and
subsequent to the inactivation of all the unspent hydrogen peroxide, reductively bleaching the bleached fibers by addition of a reductive bleaching agent to the inactivated media.
The aforementioned processes unexpectedly and surprisingly provide fibers of superior whiteness, and by virtue of preventing deposition of ferric species provide fibers having surprising, highly advantageous and desirable properties e.g. fibers which are essentially pigment free as well as stain-free, essentially free of iron residue (thereby avoiding the aforementioned undesirable reddish-brown cast) and characterized by a high degree of whiteness with low degree of damage.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a ling graph of Whiteness Index versus thiourea concentration, for a process of the present invention with in situ formation of a reductive bleaching substance using conditions referred to in example 1 and table I.
FIG. 2 is a line graph of Whiteness Index versus bleaching time after thiourea addition, for a process of the present invention (using conditions as described in example 2 and table II), showing the effect of varying bleaching time.
FIG. 3 is a line graph of Whiteness Index versus hydrogen peroxide bleaching time for conditions as referred to in example 3 and table III.
FIG. 4 is a line graph of Whiteness Index versus bath temperature: showing a comparison between conventional alkaline hydrogen peroxide bleaching and bleaching of the present invention; as referred to in example 4 and table IV.
FIG. 5 is a line graph of Whiteness Index versus Bleachit D concentration ofr a process of the present invention as referred to in example 6 and table VI.
FIG. 6 is a line graph of Whiteness Index versus thiourea dioxide concentration for a process of the present invention as referred to in example 6 and table VI.
FIG. 7 is a graph of hydrogen peroxide remaining versus bleaching time in minutes, showing decomposition of hydrogen peroxide in the bleach bath during bleaching of wool.
DETAILED DESCRIPTION OF THE INVENTION
Both of the bleaching processes of the present invention may be utilized to great advantage with any of a wide variety of fiber compositions, including animal hair fibers, plant fibers, synthetic fibers, and blends of two or more of the aforementioned (notably, fibers consisting essentially of wool, fibers consisting of cotton, and blends of wool with either materials). Said fibers may be in any suitable form which permits bleaching, including: loose fibers, yarns (twisted, woven, wrapped, etc.), fabric (e.g. woven, matted, felted), etc. Also, the fibers may be pigmented or unpigmented, and/or stained (e.g. urine-stained). Contamination of wool by urine-stained and black-pigmented fibers is viewed as a major problem of American wool. It is also a great advantage of the present invention that the processes may be carried out over a wide range of temperatures, e.g. 20° C. to 100° C. Both of the bleaching processes of the present invention permit either: (1) all steps to be carried out batch-wise in a single bath; or (2) all steps to be carried out continuously using a continuous pad system ("padding" is a process well known in the art, and is for example defined on page 109 of Textile Terms and Definitions, Fifth Edition, published by Textile Institute, August 1963). Either of the processes of the present invention may produce novel and highly advantageous fibers having unexpectedly superior properties, such as a degree of whiteness as measured by ASTM E-313 of at least about 43 degree of damage indicated by an alkali solubility of 30% or less as measured by IWTO-4-60, preferably said degree of whiteness being at least 44 with a said solubility of 25% or less, and more preferably a said degree of whiteness of at least about 46.
When the aforementioned first process of the present invention is carried out employing thiourea as the material which combines with hydrogen peroxide to form a reductive bleaching agent, it is preferred to: add the thiourea in a stoichiometric ratio to the unspent hydrogen peroxide of at least about 1 to 4 i.e. at least one mole of thiourea for each 4 moles of unspent hydrogen peroxide (more preferably in a said ratio of at least about 2 to 4, i.e. at least about 2 moles of thiourea for each 4 moles of unspent hydrogen peroxide, and most preferably in a said ratio of about 2 to 4 i.e. about 2 moles of thiourea for each 4 moles of unspent hydrogen. peroxide), and; adjust the reductive bleaching media to a pH of about 6 to about 9, more preferably about 7 to about 8. The addition of thiourea to hydrogen peroxide creates a reducing medium in situ. This will not only enhance bleaching (i.e. further whiten the fibers), but also reduces any ferric ions that may have been oxidized by hydrogen peroxide to ferrous ions which have a much lower affinity for wool than ferric ions and therefore may easily be washed away. Also, in regard to said first process, it is preferred to carry out the bleaching of fibers in the reductive bleaching media for a time period of from about 25 to about 35 minutes.
In carrying out the aforementioned second process of the present invention, it is preferred to: utilize as the inactivating material a material selected from the group consisting of:
(1) catalysts which catalyze decomposition of hydrogen peroxide, such as transition metals preferably used at a pH of from about 6 to about 10 (e.g. if necessary a suitable chemical is added to the oxidatively bleached fibers in contact with unspent hydrogen peroxide, in order to bring the pH into the range of from about 6 to about 10). Optionally, after the transition metal(s) have completed deactivation of the unspent hydrogen peroxide, a chelating agent may be added in order to chelate excess transition metal ions (if any) prior to the reductive bleaching;
(2 ) enzymes which decompose hydrogen peroxide; preferably the pH of the bleached fibers in contact with unspent hydrogen peroxide is adjusted to be from about 3 to about 10 prior to adding the enzyme. For example, suitable enzymes include catalase (which preferably is used at a pH of from about 5 to about 8.5) and enzymes referred to in chapter 8 of Hydrogen Peroxide, W. C. Schumb et al, editors, published by Reinhold Pub. Corp., N.Y., 1955;
(3) materials which react with hydrogen peroxide to render the hydrogen peroxide inactive, such as cerium (which may be provided in chemical combination with other materials, but which upon addition to the oxidatively bleached fiber and unspent hydrogen peroxide makes cerium available for reaction with hydrogen peroxide) or quinones.
While any suitable reductive bleaching agent may be utilized in said second process, it is preferred to utilize as the reductive bleaching agent either thiourea dioxide or sodium hydroxymethanesulfinate.
It is preferred, in carrying out the present invention, to carry out the step of bringing the pigmented and unpigmented fibers into contact with ferrous ion in the presence of an iron reducing agent. Examples of such agents which may be utilized in the present invention include hypophosphorous acid, phosphorous acid and sodium bisulfite.
Persulfate containing compounds useable in the present invention include salts of persulfate. Examples of specific persulfate containing compounds useable in the present invention include, ammonium persulfate, sodium persulfate and potassium persulfate.
EXAMPLES
The following examples are intended only to further illustrate the invention and are not intended to limit the scope of the invention which is defined by the claims.
In the following examples, bleaching of wool fabric was performed using an Ahiba Texomat (Ahiba Inc., Charlotte, N.C.) laboratory dyeing apparatus. Oxidation potential was monitored on a voltmeter using a Corning Platinum Redox Combination electrode (Fisher Scientific Co., Springfield, N.J.); pH was monitored on an E & K pH meter (E & K Scientific product, Saratoga, Calif.) using a combination glass electrode (Cole-Parmer International, Chicago, Ill.). All bleaching treatments were carried out at a liquor to wool ratio of 30 milliliters liquor : 1 gram of fabric. Wool samples (10 g) were bleached in various bleach bath compositions and conditions.
Whiteness (ASTM; E-313) and Yellowness (ASTM; D-1925) Indices were measured with a Colorgard System 1000 tristimulus colorimeter (Pacific Scientific Co., Silver Spring, Md.). Sample illumination was by a quartz-halogen lamp at color temperature of 2854 degrees Kelvin with 360° circumferential illumination (CIE Source C, 1931 Standard Observer Illuminant) geometry that is 45° from the sample's normal direction, sample viewing being at 0°. The equations used in the Colorgard System for the calculations of Whiteness and Yellowness Indices are: ##EQU1## where X, Y and Z are the measured tristimulus values; WI is the WHiteness Index, and YI is the Yellowness Index. The extent of degradation of the wool caused by bleaching was determined by measuring the loss in weight of the sample after immersion in 0.1 M sodium hydroxide for 1 hour at 65±0.5° C. [I.W.T.O. Technical Committee Report, 1960, IWTO-4-60(E)]. Wet tensile strength measurements of wool flannel, bleached and treated under various conditions were carried out according to the standard method as set forth in ASTM , 1981 Book of ASTM standards, Am. Soc. for Testing and Materials: Wool flannel fabric was cut into ten equal size strips of length 140 mm and width 13 mm, 5 oriented along the warp axis (18 yarns) and the other 5 along the weft axis (14 yarns). These samples were then soaked for 24 hours in an aqueous solution containing Triton X-100 (0.5 g/L). An Instron tensile testing machine (Instron Crop., Canton, Mass.) of gauge length 90 mm was used for the measurements of breaking load and elongation. The wetted-out samples were secured between the clamps and a constant rate of load was applied along the warp or weft directions until the fabric was broken.
A. Oxidative hydrogen peroxide bleaching followed by thiourea
One aspect of the present invention relates to the formation of a reductive substance in situ when thiourea is added to an oxidative hydrogen peroxide bleach bath. When using thiourea, a strong reductive substance is preferably formed under approximately neutral or slightly alkaline conditions (e.g. pH of about 6 to about 9, preferably a pH of from about 7 to about 8). The optimum stoichiometric ratio of thiourea to hydrogen peroxide was found to be about 2 to 4. An exact amount of thiourea therefore may be calculated based on the amount of unspent hydrogen peroxide remaining after a bleaching process, and that amount of thiourea may be added to the bleach bath for maximum efficiency. In the examples a marked drop in pH (pH=2 to 3) and an increase in temperature (by 5-7° C.) of solution were observed along with the appearance of incipient turbidity. The pH of the solution was then adjusted to a pH of from about 7 to about 8, at which point the oxidation potential of the solution changed markedly from a positive to a very negative value, indicative of the complete consumption of hydrogen peroxide.
EXAMPLE 1
Bleaching experiments were done in stirred bleaching vessels immersed in a stirred thermostatic bath. The substrate was a wool flannel fabric (20.60-26.39 microns in diameter, 233 g/m 2 ) with black hair contamination and urine-stained wool, kindly supplied by Forstmann and Co., Inc., Dublin, Ga. Wool flannel fabric was bleached in the alkaline hydrogen peroxide bleach bath for 1 hour at 60° C. This was then followed by addition of thiourea and the necessary pH adjustment to attain a reductive substance in situ for the reductive bleaching part of the process. The reductive bleaching was carried out for 25 minutes at the same temperature. The bleaching conditions and the results are shown in Table I and depicted graphically in FIG. 1.
TABLE I__________________________________________________________________________The effect of thiourea concentration on the oxidative/reductive bleachingof wool flannel..sup.a Warp.sup.e Weft.sup.e ReductionThiourea Whiteness Yellowness Alkali Breaking Elongation Breaking Elongation potential(g/L) Index.sup.b Index.sup.c Solubility (%).sup.d Load (N) (%) Load (N) (%) (mV).sup.f__________________________________________________________________________Unbleached 11.42 ± 0.45 23.71 ± 0.20 11.60 ± 0.43 35.62 ± 1.41 56.64 ± 1.92 24.72 ± 1.26 60.57 ± 2.79 ----.sup.g 35.85 ± 0.54 12.38 ± 0.17 22.43 ± 1.09 35.18 ± 2.58 55.32 ± 2.44 27.87 ± 0.83 55.51 ± 1.72 +2013.07 34.24 ± 0.48 13.16 ± 0.26 24.48 ± 0.49 -- -- -- -- +2263.85 38.09 ± 0.07 11.49 ± 0.03 -- -- -- -- -- -1704.61 43.15 ± 0.28 9.55 ± 0.03 22.14 ± 0.69 -- -- -- -- -6635.38 43.83 ± 0.09 9.23 ± 0.04 23.53 ± 0.37 32.43 ± 1.06 55.13 ± 1.90 22.99 ± 0.63 51.25 ± 1.88 -6986.15 43.52 ± 0.26 9.17 ± 0.16 24.00 ± 0.24 -- -- -- -- -6927.69 43.62 ± 0.05 9.23 ± 0.08 24.44 ± 0.22 32.74 ± 1.73 53.58 ± 2.37 22.39 ± 1.59 50.48 ± 2.80 -6805.38.sup.h 31.84 ± 0.40 14.51 ± 0.22 -- 43.30 ± 0.78 57.46 ± 1.72 27.82 ± 0.58 53.26 ± 0.99 -145.38.sup.i 37.14 ± 0.42 12.11 ± 0.14 -- -- -- -- -- -242__________________________________________________________________________ .sup.a Alkaline hydrogen peroxide bleaching, 60° C., 1 hr, followe by thiourea addition, pH adjustment with NaOH to pH 7.4-7.6 unless indicated, and continued bleaching, 60° C., 25 min. .sup.b As per ASTM E313; mean value ± standard deviation of 3 samples, each having 8 measurements. .sup.c As per ASTM D1925; mean value ± standard deviation of 3 samples each having 8 measurements. .sup.d As per IWTO4-60; mean value ± standard deviation of 3 samples. .sup.e As per ASTM D1682-64; mean value ± standard deviation of 5 determination. .sup.f Measured immediately after thiourea addition and pH adjustment. .sup.g I.e., alkaline hydrogen peroxide bleaching for 1 hr 25 min with no pH adjustment at 1 hr. .sup.h pH of the solution is not adjusted after the addition of thiourea (pH = 3.6). .sup.i Solution was buffered (pH = 6.8) before thiourea addition so that the reaction is carried out under neutral conditions.
Below a certain thiourea concentration (FIG. 1), no improvement in whiteness of wool flannel fabric is observed, this being due to the fact that under these conditions, a reductive substance is not formed since there is not sufficient thiourea to react with all the residual hydrogen peroxide.
______________________________________Alkaline bleach bath composition______________________________________Hydrogen peroxide (30% w/w) 20.0 mL/L of liquorTetrasodium pyrophosphate 10.0 g/L of liquordecahydrateTriton X-100 1.0 g/L of liquorInitial pH of bleach bath 9.4pH after oxidative bleaching for 8.31 hr at 60° C.Weight of wool flannel fabric 10 gLiquor to wool ratio 30 milliliters of liquor: 1 gram of wool______________________________________
Sufficient thiourea should be added to make certain that a reductive bleaching media is produced. Above a certain thiourea concentration, not further improvement of whiteness of wool flannel fabric is observed. It is also apparent from the results in Table I that the pH adjustment to 7-8 may be very advantageous for attaining a high negative oxidation potential and an improvement in the whiteness of wool flannel fabric. The pH may be adjusted to provide a suitable reduction potential so that an improvement in whiteness of the wool flannel fabric is achieved.
EXAMPLE 2
The bleaching solution composition and conditions were the same as those of Example 1 except that bleaching time after thiourea addition following alkaline hydrogen peroxide bleaching was varied. The results are shown in Table II and depicted graphically in FIG. 2.
TABLE II__________________________________________________________________________The effect of thiourea bleaching time on the oxidative/reductivebleaching of wool flannel..sup.aBleaching time Warp.sup.e Weft.sup.eafter thiourea Whiteness Yellowness Alkali Breaking Elongation Breaking Elongationaddition (min.) Index.sup.b Index.sup.c Solubility (%).sup.d Load (N) (%) Load (N) (%)__________________________________________________________________________--.sup.f 34.23 ± 0.66 13.15 ± 0.31 19.04 ± 0.33 35.32 ± 1.02 55.88 ± 1.70 28.25 ± 0.75 56.51 ± 1.0315 43.69 ± 0.18 9.18 ± 0.07 22.05 ± 0.26 -- -- -- --25 43.83 ± 0.09 9.23 ± 0.04 23.53 ± 0.37 32.43 ± 1.06 55.13 ± 1.90 22.99 ± 0.63 51.25 ± 1.8835 44.75 ± 0.07 8.87 ± 0.07 -- 31.17 ± 1.70 54.68 ± 2.82 21.97 ± 0.99 52.44 ± 1.4745 43.61 ± 0.24 9.31 ± 0.08 22.54 ± 0.72 -- -- -- --25.sup.g 44.42 ± 0.05 9.03 ± 0.01 20.63 ± 0.44 37.36 ± 1.56 58.77 ± 2.17 26.58 ± 1.36 58.04 ± 1.8525.sup.h 44.63 ± 0.63 8.93 ± 0.25 21.45 ± 0.67 36.29 ± 2.02 57.49 ± 3.41 23.57 ± 1.44 54.33 ±__________________________________________________________________________ 3.78 .sup.a As per Table I except 5.38 g/L thiourea was used for various bleaching times. .sup.b As per Table I. .sup.c As per Table I. .sup.d As per Table I. .sup.e As per Table I. .sup.f I.e., alkaline hydrogen peroxide bleaching for 60 min, with neithe subsequent pH adjustment nor addition of thiourea. .sup.g pH was adjusted to 7.1 (6 mL of 30% w/v Na.sub.2 CO.sub.3 solution after thiourea addition. .sup.h pH was adjusted to 7.4 (7.5 g NaHCO.sub.3) after thiourea addition
The results in Table II show that the bleaching time after thiourea addition is not critical in the time range studied (15-45 min.). Bleaching times of 25-35 minutes after thiourea addition are preferred. Alkali solubility values are seen to be well below the critical value of 30% as referred to in Ziegler, K. Textil-Praxis, 71, 376(1962). It is also shown in Table II that for the operating conditions of the instant example, that the pH of the bleach solution after thiourea addition may be raised to achieve a high negative oxidation potential; a pH of 7-8, obtained by weak alkalis such as sodium carbonate and bicarbonate, is as sufficient for achieving high bleaching efficiencies as higher values obtained with sodium hydroxide. The pH adjustment may be made with weak alkalis on large scale bleaching trials to avoid unwanted damage to wool that might occur from use of sodium hydroxide and uneven mixing.
EXAMPLE 3
The bleaching solution composition and conditions were the same as those of Example 1 except the initial alkaline hydrogen peroxide bleaching time prior to thiourea addition was varied. The results, as shown in Table III and depicted graphically in FIG. 3, demonstrate that the longer the hydrogen peroxide bleaching part of the process, the whiter the bleached wool flannel fabric.
TABLE III__________________________________________________________________________The effect of varying the hydrogen peroxide bleaching timeon the oxidative/reductive bleaching of wool flannel..sup.aOxidative Warp.sup.e Weft.sup.ebleaching Whiteness Yellowness Alkali Breaking Elongation Breaking Elongationtime (min.) Index.sup.b Index.sup.c Solubility (%).sup.d Load (N) (%) Load (N) (%)__________________________________________________________________________ 0.sup.f 31.84 ± 0.19 13.89 ± 0.02 -- -- -- -- --20 39.43 ± 0.38 10.97 ± 0.16 -- -- -- -- --40 42.56 ± 0.15 9.69 ± 0.06 20.12 ± 0.34 -- -- -- --60 43.52 ± 0.26 9.38 ± 0.04 24.00 ± 0.24 32.56 ± 1.51 54.90 ± 2.05 22.60 ± 1.20 50.95 ± 1.3080 46.82 ± 0.16 8.04 ± 0.04 24.29 ± 0.13 30.91 ± 1.30 56.31 ± 1.35 19.20 ± 1.28 48.44 ± 1.22__________________________________________________________________________ .sup. a As per Table I except 6.15 g/L thiourea is used. .sup.b As per Table I. .sup.c As per Table I. .sup.d As per Table I. .sup.e As per Table I. .sup.f Thiourea mixed with hydrogen peroxide and pH adjusted with no prio time for oxidative bleaching.
Here it must be emphasized that in the process of this example, that the wool flannel fabric to be bleached should first be given an oxidative peroxide bleaching prior to thiourea addition. This is simply demonstrated by the results given in Table III where the wool flannel fabric was not given an initial peroxide bleach. Hydrogen peroxide, thiourea and all the other additives were mixed at the start of the bleaching treatment and bleaching was allowed to proceed for 20 minutes. The importance of initial hydrogen peroxide bleaching becomes more apparent when the Whiteness Index values of wool bleached for 60 minutes (with all chemicals mixed at the start i.e. as taught by Japan 51-64082) are compared with those of wool bleached for 65 minutes (40 minutes alkaline peroxide bleach followed by thiourea addition and bleaching for 25 minutes after pH adjustment). Although in both cases a high negative oxidation potential was attained, it seems that the initial oxidative hydrogen peroxide bleaching somehow modifies wool sufficiently so that a follow-up reductive bleaching further whitens wool effectively.
EXAMPLE 4
The bleaching solution composition was the same as per Example 1. In the present example, a direct comparison of conventional alkaline hydrogen peroxide bleaching to that of the new invention (oxidative/reductive single-bath process) at different bleaching temperatures is made and the results are shown in Table IV and depicted graphically in FIG. 4.
TABLE IV__________________________________________________________________________The effect of bleaching temperature on theoxidative/reductive bleaching of wool flannel..sup.aTreatment Thiourea Total time of Whiteness Yellowness Alkalitemperature (°C.) addition bleaching (min.) Index.sup.b Index.sup.c Solubility (%).sup.d__________________________________________________________________________55 No 65 32.76 ± 0.39 13.77 ± 0.16 --55 Yes 65 40.11 ± 0.33 10.73 ± 0.15 --60 No 65 34.23 ± 0.66 13.15 ± 0.31 19.04 ± 0.3360 Yes 65 42.46 ± 0.15 9.69 ± 0.06 20.12 ± 0.34 60.sup.e Yes 60 33.89 ± 0.94 13.51 ± 0.35 --65 No 65 37.63 ± 0.33 11.57 ± 0.13 28.23 ± 0.6365 Yes 65 44.05 ± 0.31 9.00 ± 0.18 25.15 ± 0.5270 No 65 39.36 ± 0.28 10.96 ± 0.11 32.61 ± 0.9970 Yes 65 45.43 ± 0.23 8.46 ± 0.14 28.88 ± 0.37__________________________________________________________________________ .sup.a Alkaline hydrogen peroxide bleaching at different temperatures, 40 min., followed by thiourea addition (6.15 g/L; pH adjustment with NaOH to pH 7.4-7.6 only in the thiourea cases), and continued bleaching for 25 min. .sup.b As per Table I. .sup.c As per Table I. .sup.d As per Table I. .sup.e Thiourea mixed with hydrogen peroxide and pH adjusted with no prio time for oxidative bleaching.
It is noteworthy that the same level of whiteness is reached at a bleaching temperature of 55° C. with the hydrogen peroxide-thiourea bleaching system (oxidative/reductive) as at 70° C. with the hydrogen peroxide system alone. Furthermore the former process is less damaging to the wool, as evidenced by lower alkali solubilities.
EXAMPLE 5
______________________________________Acidic bleach bath composition______________________________________Hydrogen peroxide (30% w/w) 20.0 mL/L of liquorPrestogen NB-W 3.43 g/L of liquorTriton X-100 1.0 g/L of liquorInitial pH of bleach bath 5.7pH after oxidative bleaching for 5.21 hr. at 80° C.Weight of wool flannel fabric 10 gLiquor to wool ratio 30 milliliter liquor: 1 gram of fabric______________________________________
Prestogen NB-W (BASF Chemicals Division, Charlotte, N.C.) is a mixture of organic acid salts in aqueous solution which activates hydrogen peroxide at mildly acid pH values by forming peroxy compounds.
In this example, we demonstrate the effectiveness of the hydrogen peroxide-thiourea system on the bleaching efficiency under acidic oxidative bleaching with hydrogen peroxide followed by thiourea. The results are shown in Table V.
TABLE V__________________________________________________________________________The effect of thiourea on the oxidative/reductive bleaching of woolflannel..sup.aTotal time Warp.sup.e Weft.sup.eThiourea of bleaching Whiteness Yellowness Alkali Breaking Elongation Breaking Elongation(g/L) (min.) Index.sup.b Index.sup.c Solubility (%).sup.d Load (N) (%) Load (N) (%)__________________________________________________________________________-- 65 29.12 ± 0.12 16.24 ± 0.30 28.49 ± 0.30 37.25 ± 2.04 66.15 ± 2.48 24.39 ± 0.47 59.33 ± 2.005.38 65 42.56 ± 0.29 10.13 ± 0.14 21.72 ± 0.84 27.97 ± 1.83 56.82 ± 3.11 17.99 ± 1.26 51.88 ± 2.84-- 85 29.26 ± 0.33 16.03 ± 0.12 -- 34.06 ± 0.31 63.11 ± 2.32 26.88 ± 1.85 63.75 ± 4.485.38 85 43.60 ± 0.21 9.51 ± 0.28 -- 24.53 ± 0.83 53.46 ± 3.18 19.72 ± 0.88 56.22 ±__________________________________________________________________________ 1.63 .sup.a Acidic hydrogen peroxide bleaching (as per experimental) for 40 or 60 min at 80° C., followed, when indicated, by thiourea addition, (pH adjustment with NaOH to pH 7.4-7.6), and continued bleaching at 80° C. for 25 min. .sup.b As per Table I. .sup.c As per Table I. .sup.d As per Table I. .sup.e As per Table I.
It is seen from the results that the bleaching efficiency are markedly improved with the hydrogen peroxide-thiourea system as compared to an oxidative acidic hydrogen peroxide bleaching alone. The decrease in breaking load and elongation noted in Table V for acidic oxidative/reductive bleaching is not understood, but is inconsistent with the alkali solubility results.
B. Direct addition of reductive substance to a decomposed oxidative hydrogen peroxide bleach bath
It is well known that typically only a small fraction of hydrogen peroxide is consumed or decomposed during an efficient and effective bleaching process. In a typical two step, two-bath oxidative/reductive process, the goods are first bleached oxidatively using hydrogen peroxide (alkaline or acidic). They are then removed from the first bath and bleached in the second bath with a reducing agent. This process is not only costly but also time-consuming, since both baths must be heated up to a suitable temperature.
The principle behind this aspect of the present invention is that the active surplus hydrogen peroxide remaining after an oxidative bleaching treatment may be successfully decomposed with no adverse effect on the fiber or subsequent chemical treatment, thus allowing a reductive substance to be added to the bath directly. This is particularly sound for a single-bath process, since the bath is already in the temperature range suitable for subsequent reductive bleaching. There are many inorganic catalysts (such as, transition metals, e.g. iron, copper, manganese, cobalt, etc.) and enzymes that will decompose hydrogen peroxide.
A typical set of conditions would be as follows:
______________________________________Hydrogen peroxide (30% w/w) 20 mL/L of liquorTetrasodium pyrophosphate decahydrate 10 g/L of liquorTriton X-100 1 g/L of liquor______________________________________
Wool fabric (10 g) was bleached with the above solution at a liquor to goods ratio of 30 milliliter liquor : 1 gram of wool for 60 minutes at 60° C. The pH of the bleach liquor was then adjusted to 8.8 and CoSO 4 (25 mg/L) was added to the bleach bath. Rapid evolution of oxygen was observed and the decomposition of hydrogen peroxide was complete within 10-15 minutes as the titration against acidified KMnO 4 showed. At this stage, a chelating agent such as nitrilotriacetic acid trisodium salt could be added to complex with the free Co ions and the pH of the solution could be adjusted to the desired value for the reductive bleaching part of the process.
The above is a specific set of typical conditions, but in general the conditions may be varied. It is found that hydrogen peroxide may be decomposed efficiently in the pH range 7.8-9.0 and temperature range 80-60° C. with no adverse effect on wool. Reductive bleaching is either carried out under neutral or acidic conditions. Therefore, after the decomposition of hydrogen peroxide and the pH adjustment, the temperature of the bath may be increased to the desired temperature to obtain optimum bleaching yields.
EXAMPLE 6
In this example the effect of reductive bleaching (sodium hydroxymethanesulfinate [Bleachit D(BASF Chemical Division, Charlotte, N.C.)] or thiourea dioxide) is demonstrated under various conditions as an aftertreatment following an oxidative alkaline hydrogen peroxide bleaching. The results of bleaching trials are shown in Table VI and depicted graphically in FIGS. 5 and 6.
TABLE VI__________________________________________________________________________The effect of reductive agent aftertreatment (Bleachit D, thioureadioxide) on theoxidative/reductive bleaching of wool flannel..sup.aBath Hydrogen Thioureatemperature peroxide Bleachit D dioxide Whiteness Yellowness Alkali(°C.) (mL/L) (g/L) (g/L) Index.sup.b Index.sup.c Solubility (%).sup.d__________________________________________________________________________60 20.sup.e -- -- 35.85 ± 0.54 12.38 ± 0.17 22.43 ± 1.0960 20.sup.f 1.0 -- 39.84 ± 0.42 10.66 ± 0.21 24.58 ± 0.4760 20.sup.f 2.0 -- 39.93 ± 0.27 10.58 ± 0.07 --60 20.sup.f 4.0 -- 40.80 ± 0.07 10.60 ± 0.03 24.59 ± 0.6970 20.sup.e -- -- 39.33 ± 0.36 10.94 ± 0.17 30.73 ± 0.7870 20.sup.g -- 1.0 35.75 ± 0.66 12.51 ± 0.24 22.65 ± 0.6770 20.sup.g -- 2.0 41.21 ± 0.13 10.26 ± 0.19 --70 20.sup.g -- 3.0 42.14 ± 0.28 9.69 ± 0.08 22.51 ± 0.3270 20.sup.g -- 5.0 43.26 ± 0.52 9.24 ± 0.19 --__________________________________________________________________________ .sup.a As per experimental; residual hydrogen peroxide quenched using CoSO.sub.4 prior to reductive bleaching. .sup.b As per Table I. .sup.c As per Table I. .sup.d As per Table I. .sup.e Alkaline hydrogen peroxide bleaching for 1 hour and 25 minutes, as per Table I, note g. .sup.f As per e, but for 50 minutes, followed by peroxide decomposition with CoSO.sub.4 for the next 10 minutes at pH 8.8 and finally reductive bleaching (Bleachit D, pH adjusted to 2.5) at the same temperature for 25 minutes. .sup.g As per `f` except for reductive bleaching agent (thiourea dioxide, pH adjusted to 6.5-7.0). In the process of the instant example, the decomposition of residual hydrogen peroxide is essential; preliminary experiments showed that large amounts of reductive agents (thiourea dioxide, sodium hydroxymethanesulfinate) were needed to consume all the residual hydrogen peroxide before a high negative oxidation potential could be attain upon addition of the reductive agent. It should also be noted that thiourea dioxide, unlike sodium hydroxymethanesulfinate, does not produce a high negative oxidation potential under acidic conditions; therefore, with thiourea dioxide it is preferred to utilize a pH of about 6.5-7.0. For reasons of economy it is preferred that all residual hydrogen peroxide after oxidative bleaching be completely decomposed so that an addition of only a relatively small amount of reductive substance creates the reduction potential that is needed for the latter part of the process.
EXAMPLE 7
COMPARATIVE EXAMPLE
The purpose of this example is to show the increased effectiveness of the present invention as compared to the processes of German Patent DE 3433926 A1 (3/27/86) and Japanese Patent JP 51-64082 (6/3/76). The German patent discloses a single-bath process whereby a reductive bleaching with thiourea dioxide precedes an oxidative hydrogen peroxide bleaching. In that patent, two processes--one with and one without thiourea dioxide--were compared and it was concluded that the process with thiourea dioxide was favorable to the one without. The optimum bleaching conditions were said to be a reductive bleaching with a buffer mixture (pH=7.8, 4 g/L) containing thiourea dioxide (0.36 g/L) for 20 minutes at 80° C. followed by a direct addition of hydrogen peroxide (20 mL/L of 35% w/w solution) and further bleaching for 60 minutes at the same temperature. The Japanese patent mentions a process whereby thiourea and hydrogen peroxide are mixed at the start of the bleaching process (i.e., no prior oxidative bleaching) and there is no prescribed pH adjustment. Optimum bleaching conditions were said to be 2.91 g/L hydrogen peroxide (30% w/w) and 2.0 g/L thiourea at 95° C. for 20 minutes.
All the above processes were repeated in the exact manner outlined in the patents and the results along with those of our invention are shown in Table VII.
TABLE VII__________________________________________________________________________Comparison of different bleaching processes.ProcessTreatment Hydrogen Thiourea Thiourea Bleachit D Whiteness Yellowness AlkaliType.sup.atemperature (°C.) peroxide (g/L) (g/L) dioxide (g/L) (g/L) Index.sup.b Index.sup.c solubility__________________________________________________________________________ (%).sup.dA 60 20 5.38 -- -- 43.83 ± 0.09 9.23 ± 0.04 23.53 ± 0.37B 80 20 5.38 -- -- 42.56 ± 0.29 9.51 ± 0.28 21.72 ± 0.84C 80 20 -- 0.36 -- 35.31 ± 0.07 13.29 ± 0.02 27.40 ± 0.64C 80 20 -- -- -- 32.59 ± 0.21 14.36 ± 0.07 --D 95 2.91 2.0 -- -- 20.33 ± 0.50 18.87 ± 0.15 --E 60 20 -- -- 4.0 40.80 ± 0.07 10.60 ± 0.03 24.59 ± 0.69F 70 20 -- 5.0 -- 43.26 ± 0.52 9.24 ± 0.19 --__________________________________________________________________________ .sup. a A (Our Process): Alkaline hydrogen peroxide bleaching followed by thiourea, as per Table I, note a; B (Our Process): Acidic hydrogen peroxide bleaching followed by thiourea, as per Table V, note a; C (Germa Patent): Reductive bleaching with thiourea dioxide at pH 7.8 for 25 min, followed by hydrogen peroxide bleaching for 60 min,; D (Japanese Patent): Hydrogen peroxide and thiourea mixed at start of bleaching process with n pH adjustment; E (Our Process): As per Table VI, note f; F (Our Process): As per Table VI, note g. .sup.b As per Table I. .sup.c As per Table I. .sup.d As per Table I.
It is clearly seen that the present invention processes (A, B, E, F) give more effective bleaching (i.e. higher Whiteness Index, lower Yellowness Index and lower alkali solubility) than either of the other processes (C or D). Process type C (Table VII; reductive/oxidative) with thiourea dioxide is a near reverse of the present invention processes A, B, E and F (oxidative/reductive). One would therefore expect similar results. The differences that were observed must be a function of the process sequence, since high negative oxidation potentials were observed in all these processes. One may therefore conclude from this that in a single-bath bleaching process, an oxidative hydrogen peroxide bleaching must be carried out first, and only then followed by a reductive bleach.
C. Initial Treatment with ferrous ions followed by bleaching in accordance with the aforementioned processes
The wool used was a flannel fabric (Whiteness Index=-4.40, Yellowness Index=32.70, 507 g/m 2 ) heavily contaminated with black hair and urine-stained wool, kindly supplied by Forstmann and Co., Inc., Dublin, Ga. The hydrogen peroxide used was a 30% (w/w) aqueous solution. The non-ionic wetting agent Triton X-100 was provided by Rohm and Haas Co., Philadelphia, Pa. Tetrasodium pyrophosphate decahydrate was obtained from Aldrich Chemicals Co., Inc., Milwaukee, Wis. All other chemicals used were of A.C.S. grade. Mordanting and bleaching of wool fabric were performed using an Ahiba Texomat (ahiba Inc., Charlotte, N.C.) laboratory dyeing apparatus. All laboratory mordanting and bleaching trials were carried out at a liquor/wool ratio of 30 milliliters to 1 gram of fabric.
(1) Mordanting:
Wool flannel fabric (10.0 grams) was introduced into the mordant bath at 40° C. and the temperature was then raised to 80° C. over a period of 20 minutes. Mordanting was further carried out at this temperature for 1 hour.
Mordant Solution
FeSO 4 ·7H 2 O (10.0 grams/liter)
Reducing Agent
Hypophosphorous acid (0.2 gram/liter) or
Sodium bisulfite (2.0 gram/liter)
Triton X-100 (1.0 gram/liter)
pH (initial)=2.87
pH (after mordanting)=3.45
(2) Rinsing:
The flannel was then removed and thoroughly rinsed 4 times in changes of deionized water at 80° C., each rinsing being for 5 minutes under acidic conditions (pH=2.0-3.5). The flannel was then air-dried.
(3) Bleaching:
Bleaching was carried out under alkaline conditions for a specified time and temperature in the bleach bath of composition as listed below.
Bleach Solution
Hydrogen peroxide (30% w/w; 20.0 ml/liter)
Tetrasodium pyrophosphate decahydrate (10.0 grams/liter)
Triton X-100 (1.0 g/l)
Aqueous ammonia, if necessary, to pH 8.0-8.5
pH (initial)=9.37
pH (final)=8.2-8.5
Using the aforementioned methods and materials the following processes were carried out:
Process A--Alkaline hydrogen peroxide bleaching for 90 minutes at 60° with no prior mordanting;
Process B--As per A except thiourea (5.83 grams/liter) was added, pH adjusted to 7-8 and bleaching continued over the last 30 minutes;
Process C--Mordanting using ferrous sulfate (10.0 grams/liter) and hypophosphorous acid (0.20 grams/liter) for 1 hour at 80° C., followed by thorough rinsing with deionized water at 80° C. and finally bleaching with alkaline hydrogen peroxide for 90 minutes at 60° C.;
Process D--As per C except thiourea (5.83 grams/liter) was added, pH adjusted to 7-8 and bleaching continued in the last 30 minutes;
Process E--Mordanting using ferrous sulfate (10.0 grams/liter) and sodium bisulfite (2.0 grams/liter) for 1 hour at 80° C., followed by thorough rinsing with deionized water at 80° C. and finally bleaching using alkaline hydrogen peroxide for 90 minutes at 60° C.;
Process F--As per E except thiourea (5.83 grams/liter) was added, pH adjusted to 7-8 and bleaching continued over the last 30 minutes.
Results were as shown in the following Table.
TABLE VIII______________________________________ Alkali Whiteness Yellowness SolubilityPROCESS Index.sup.a Index.sup.b (%).sup.c______________________________________A: H.sub.2 O.sub.2 15.09 ± 0.20 23.47 ± 0.07 21.50 ± 0.63B: A, then thiourea 19.33 ± 0.32 21.28 ± 0.11 18.21 ± 0.43C: Fe.sup.2+, H.sub.3 PO.sub.2, 14.47 ± 0.34 23.97 ± 0.13 22.24 ± 0.21then AD: Fe.sup.2+, H.sub.3 PO.sub.2, 19.49 ± 0.04 21.43 ± 0.03 20.13 ± 0.95then BE: Fe.sup.2+, NaHSO.sub.3, 21.73 ± 0.24 22.72 ± 0.01 26.95 ± 0.82then AF: Fe.sup.2+, NaHSO.sub.3, 26.14 ± 0.31 20.55 ± 0.12 23.11 ± 0.09then B______________________________________ .sup.a As per ASTM E313; mean value of 3 samples ± standard deviation, each sample having 8 measurements. .sup.b As per ASTM D1925; means value of 3 samples ± standard deviation, each sample having 8 measurements. .sup.c As per IWTO4-60; mean value of 3 samples ± standard deviation.
It is seen from Table VIII that the differences in Whiteness and Yellowness Indices of the samples treated by processes A and C are very small, even though one would have expected to obtain a whiter sample with the mordanted wool (treatment process C). There are two possible explanations to account for this. First, the samples used in the investigations are urine-stained wool with black hair contamination. Since the conditions were selected to yield optimum selective bleaching of black hair, the bleaching of the non-pigmented areas-the majority of the wool fibers-was not expected to be higher in one case over the other. The color indices are not expected to be sensitive to changes in the relatively few pigmented fibers. The human eye, however, is more discriminatory; close examination reveals that the black hairs in the case of the bleached mordanted wool have turned into a pale light brown shade that blend well with the background color of wool. In the case of the bleached non-mordanted wool, the situation is quite different; the black hairs were only negligibly lightened and are still readily detected by the eye. Second, ferrous ions, even if present in only a small amount after the rinsing step, may cause a red-brown discoloration to the overall appearance of wool as a result of oxidation of ferrous species by hydrogen peroxide during the bleaching stage. This may well account for the small differences in the Whiteness and Yellowness Indices of the mordanted vs. non-mordanted bleached wool (process C vs. A).
the effect of different reducing agents during mordanting on the bleaching efficiency of wool was also investigated, i.e. a comparison of hypophosphorous acid to sodium bisulfite (Table VIII; processes C and E, respectively). Both compounds were found to be effective reducing agents in the application of ferrous ions onto wool and thus effective for selectively bleaching black hair. When the results of the bleaching trials are closely compared, it is easily seen that bleached wool mordanted in the presence of sodium bisulfite has a higher Whiteness Index but also a higher Yellowness Index than the wool mordanted in the presence of hypophosphorous acid. This is due to the fact that the wool mordanted in the presence of sodium bisulfite absorbed more iron (much darker color appearance after mordanting) than that mordanted in the presence of hypophosphorous acid. The excess iron will lead to greater reaction of hydrogen peroxide and hence enable more efficient bleaching. The bleached wool sample, however, is yellower. Measurements of hydrogen peroxide decomposition during bleaching in the presence of wool samples that had undergone different treatments are shown in FIG. 7. Enhanced decomposition of hydrogen peroxide is seen using wool that was mordanted in the presence of sodium bisulfite.
Absorption of excessive amounts of iron during mordanting and retainment after thorough rinsing may cause excessive damage to wool during bleaching. This is reflected in the alkali solubility results that are presented in Table VIII. Note the higher alkali solubility in the case of iron and sodium bisulfite treated wool. We infer from our data that bisulfite is not as good a reducing agent as hypophosphorous acid for stabilizing ferrous species on wool, that excessive amounts of ferric ion form on the wool (and are even visible as a reddish-brown discoloration), and that subsequent rinsing followed by treatment with hydrogen peroxide leads to excessive decomposition of peroxide and limited damage to the wool fiber despite good whiteness.
The results of the bleaching trials in combination with thiourea are also presented in Table VIII. IT is clearly seen from the results in Table VIII that any of the bleaching trials that are mentioned above, when combined with thiourea and appropriate pH adjustment, yield much superior bleaching. This is very apparent when treatment processes A and B, C and D, and E and F are compared. The increase in Whiteness Index values and the decrease in Yellowness Index values are due to further bleaching of heavily yellow stained wool and the substantial lightening of the background discoloration caused by ferric species.
The effect of various agents such as oxalic acid, sodium oxalate, and EDTA-disodium salt on the lightening of background discoloration on wool were investigated and the results are presented in the following Table.
TABLE IX.sup.a______________________________________After Treatment Whiteness Yellowness Alkali(conc., grams/liter) Index Index Solubility______________________________________None 20.89 ± 0.03 23.06 ± 0.13 20.65 ± 0.54Oxalic acid (3.0) 17.09 ± 0.84 24.99 ± 0.32 19.63 ± 1.36Sodium oxalate (3.0) 19.79 ± 0.24 23.60 ± 0.09 --EDTA, Na.sub.2 salt 19.34 ± 0.04 23.93 ± 0.07 --(3.0)Thiourea (5.83) 25.47 ± 0.32 20.62 ± 0.18 --pH 7-8Thiourea.sup.b (5.83) 27.78 ± 0.59 19.70 ± 0.28 16.44 ± 0.25pH 7-8______________________________________ .sup.a Mordanting using ferrous sulfate (10.0 grams/liter) and hypophosphorous acid (0.2 grams/liter) for 1 hour at 80° C., followed by thorough rinsing with deionized water at 80° C. and finally bleaching using alkaline hydrogen peroxide for 65 minutes at 65° C. Aftertreatment is done, where stated, in the last 5 minutes of the bleaching stage. .sup.b As per footnote a except alkaline hydrogen peroxide bleaching is carried out for 40 minutes at 65° C., followed by thiourea addition, pH adjustment to 7-8 and further bleaching for 25 minutes.
Whiteness index, yellowness index and alkali solubility were as per Table VIII. These results, in turn, were compared to those of no aftertreatment and thiourea treatment. It was thought that the above mentioned agents would chelate with and solubilize the iron present on wool after the bleaching stage and hence lighten the background discoloration. However, no after-treatments except thiourea gave any improvement in the lightening of wool as compared to the wool not given an after-treatment. The reaction of thiourea with the residual hydrogen peroxide after the bleaching stage and the necessary pH adjustment create a highly reductive medium that reduces any ferric species that may be present on wool to the ferrous form, which is easily washed away due to its much smaller affinity to unpigmented wool. Prolonged treatment with thiourea (25 minutes as compared to 5 minutes) yielded a whiter and less yellow sample due to further bleaching of the heavily yellow-stained wool. The alkali solubilities in all cases are within acceptable limits.
D. Oxidative Bleaching Using Hydrogen Peroxide/Persulfate Followed By the Aforementioned Processes Of Reductive Bleaching In The Same Bath
EXAMPLE 8
Bleaching experiments were done in stirred bleaching vessels immersed in a stirred thermostatic bath. The substrate was a wool flannel fabric (507/g/M 2 ) heavily contaminated with black hair and urine-stained wool, kindly supplied by Forstmann and Co., Inc., Dublin, Ga. The hydrogen peroxide was a 30% (w/w) aqueous solution. The non-ionic wetting agent Triton X-100 was provided by Rohm and Haas Co., Philadelphia, Pa. Tetrasodium pyrophosphate decahydrate was obtained from Aldrich Chemical Co., Inc., Milwaukee, Wis. All other chemicals used were of A.C.S. grade. All laboratory bleaching trials were carried out at a liquor/wool ratio of 30 milliliters to 1 gram of fabric.
BLEACHING
Bleaching was carried out under alkaline conditions for a specified time and temperature in the bleach bath of composition as listed below:
______________________________________Bleach Solution______________________________________Hydrogen Peroxide (30% w/w; 20.0 ml/liter)Tetrasodium Pyrophosphate Decahydrate (10.0 grams/liter)Ammonium Persulfate (3.0 grams/liter) (3.0 grams/liter)Triton X-100 (1.0 gram/liter)______________________________________
Aqueous Ammonia, if necessary, to PH 8.0-8.5. On addition of ammonium persulfate, the solution pH rapidly drops from about 9.4, to under 6. Sufficient ammonia is added to adjust pH back to 8.2-8.5.
pH (initial)=6.00
pH (final)=8.2-8.5
Using the formulations above, the following processes were carried out.
Process A: Bleaching with the above composition for 90 minutes at 60° C.;
Process B: As per process A for 60 minutes, then addition of thiourea (5.83 grams/liter), pH adjustment to 7-8 and continuation of bleaching for 3 minutes.
The results were as follows:
______________________________________ Whiteness Index Yellowness Index (E-313) (D-1925)______________________________________Control -4.40 ± 0.30 32.70 ± 0.16Process A 11.59 ± 0.63 25.27 ± 0.24Process B 16.43 ± 0.30 22.74 ± 0.10______________________________________
The foregoing examples and detailed description s are given merely for purposes of illustration. Modifications and variations may be made therein without departing from the spirit and scope of the invention. | The present invention is drawn to new processes for sequential oxidative and reductive bleaching of pigmented and unpigmented fibers (e.g. natural, synthetic, or blends thereof) e.g. in a single bath, which provide superior bleaching with less physical damage. Said processes including processes comprised of: (1) adsorption of ferrous ions by pigmented and unpigmented fibers; (2) removing a portion of the ferrous ions from the fibers, with at least a portion of the ions remaining on the pigmented fibers; (3) contacting the fibers with hydrogen peroxide to provide oxidative bleaching including bleaching by interaction with the ferrous ions; (4) adding either (a) a material which combines with hydrogen peroxide to form a reductive beaching agent, or (b) an inactivating material to inactivate unspent hydrogen peroxide with subsequent addition of a reductive bleaching agent, and; (5) reductively bleaching the already oxidatively bleached fibers. The aforementioned processes provide the advantages of preventing deposition of ferric species and producing fibers which are essentially free of iron residue. The present invention also encompasses processes employing hydrogen peroxide and at least one persulfate containing compound, rather than the aforementioned iron-mordanting. The instant invention produces fibers having surprising, highly advantageous, and desirable properties, e.g. fibers which are essentially pigment free, have a high degree of whiteness with low degree of damage. | 3 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a divisional of U.S. patent application Ser. No. 10/722,079, filed Nov. 25, 2003. The disclosure of the above application is incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
The present invention relates to data storage devices, and more particularly to preamplifiers and read channel circuits in data storage devices.
BACKGROUND OF THE INVENTION
Referring now to FIG. 1 , an exemplary data storage device 10 is shown. A buffer 18 stores data that is associated the control of a hard disk drive. The buffer 18 may employ SDRAM or other types of low latency memory. A processor 22 performs processing that is related to the operation of the hard disk drive. A hard disk controller (HDC) 26 communicates with the buffer 18 , the processor 22 , a host 24 , a spindle/voice coil motor (VCM) driver 30 , and/or a read/write channel circuit 34 .
During a write operation, the read/write channel circuit or read channel circuit 34 encodes the data to be written onto the storage medium. The read/write channel circuit 34 processes the signal for reliability and may include, for example error correction coding (ECC), run length limited coding (RLL), and the like. During read operations, the read/write channel circuit 34 converts an analog output from the medium to a digital signal. The converted signal is then detected and decoded by known techniques to recover the data written on the hard disk drive.
One or more hard drive platters 52 include a magnetic coating that stores magnetic fields. The platters 52 are rotated by a spindle motor that is schematically shown at 54 . Generally the spindle motor 54 rotates the hard drive platter 52 at a fixed speed during the read/write operations. One or more read/write arms 58 move relative to the platters 52 to read and/or write data to/from the hard drive platters 52 . The spindle/VCM driver 30 controls the spindle motor 54 , which rotates the platter 52 . The spindle/VCM driver 30 also generates control signals that position the read/write arm 58 , for example using a voice coil actuator, a stepper motor or any other suitable actuator.
A read/write device 59 is located near a distal end of the read/write arm 58 . The read/write device 59 includes a write element such as an inductor that generates a magnetic field. The read/write device 59 also includes a read element (such as a magneto-resistive (MR) element) that senses the magnetic fields on the platter 52 . A preamplifier (preamp) circuit 60 amplifies analog read/write signals. When reading data, the preamp circuit 60 amplifies low level signals from the read element and outputs the amplified signal to the read/write channel circuit 34 . While writing data, a write current that flows through the write element of the read/write device 59 is switched to produce a magnetic field having a positive or negative polarity. The positive or negative polarity is stored by the hard drive platter 52 and is used to represent data.
Referring now to FIG. 2 , the read channel circuit 34 outputs write signals w dx and w dy to the preamp circuit 60 when writing data. The preamp circuit 60 amplifies the write signals using a write amplifier 90 . The amplified write signals are output to the read/write device 59 . When reading data, the preamp circuit 60 receives signals from the read/write device 59 , amplifies the signals using a read amplifier 92 and outputs amplified read signals r dx and r dy to the read channel circuit 34 . In current data storage device architectures, there is no way to test whether the preamp circuit 60 is operating properly. Therefore, it is difficult to diagnose malfunctions in the preamp circuit 60 .
SUMMARY OF THE INVENTION
A data storage device preamp circuit according to the present invention includes a write amplifier having an input and an output. A read amplifier has an input and an output. A loopback circuit selectively connects the output of the write amplifier to the output of the read amplifier.
In other features, the write amplifier amplifies a write signal from a read channel circuit and outputs the amplified write signal to a read/write device. The read amplifier amplifies a read signal that is received from the read/write device and outputs the amplified read signal to the read channel circuit.
In still other features, the loopback circuit includes at least one of a switch and a multiplexer that selectively connects the output of the write amplifier to the output of the read amplifier.
In still other features, a trigger controls the switch and/or the multiplexer. Alternatively, the switch and/or the multiplexer is controlled by a write enable signal from the read channel circuit.
A read channel circuit for a data storage device according to the present invention includes a first counter that generates a first count of an attribute of a write signal that is output by the read channel circuit. A second counter generates a second count of the attribute of a looped-back write signal that is received by the read channel circuit.
In other features, a comparator compares a difference between the first count and the second count to a threshold and outputs a first state when the difference is less than the threshold and a second state when the difference is not less than the threshold. The read channel circuit generates a write enable signal that is output to a preamp circuit to enable a loopback mode of the preamp circuit. The attribute can be a rising edge, a falling edge and a pulse.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
FIG. 1 is a functional block diagram of an exemplary data storage device according to the prior art;
FIG. 2 is a functional block diagram of a read channel circuit and preamp circuit according to the prior art;
FIG. 3A is a functional block diagram of a first exemplary read channel circuit and a preamp circuit with switched loopback according to the present invention;
FIG. 3B is a functional block diagram of a first exemplary read channel circuit and a preamp circuit with multiplexed loopback according to the present invention;
FIG. 4 is a functional block diagram of a second exemplary read channel circuit and preamp circuit with loopback according to the present invention;
FIG. 5 is a functional block diagram of a third exemplary read channel circuit and preamp circuit with loopback according to the present invention;
FIG. 6 is a functional block diagram of a fourth exemplary read channel circuit and preamp circuit with loopback according to the present invention;
FIG. 7 is a functional block diagram of a read channel circuit that includes a data generator, a delay element and a comparator and preamp circuit with loopback according to the present invention; and
FIG. 8 is a functional block diagram of a hard drive controller that includes a data generator, a delay element and a comparator, a read channel circuit and preamp circuit with loopback according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. For purposes of clarity, the same reference numbers will be used in the drawings to identify similar elements.
Referring now to FIG. 3A , a functional block diagram of a read channel circuit 100 and a preamp circuit 102 according to the present invention is shown. The read channel circuit 100 includes a first counter 104 that counts an attribute of the write signal w ax and w ay . An output of the first counter 104 is input to a comparator 106 , which has a threshold Th. A second counter 108 counts the selected attribute of the read signal r ax and r ay that is received from the preamp circuit 102 . For example, the counters 104 and 108 can count a rising edge, a falling edge, a pulse and/or any other attribute of the write signal and the looped-back write signal. The counted attributes allow a comparison to be made between the write signal and the looped-back write signal, which indicates the operability of the preamp circuit 102 .
The preamp circuit 102 includes a write amplifier 114 that is located in the write path. The write amplifier 114 amplifies the write signal w ax and w dy and outputs the amplified write signal to the read/write device 59 . The preamp circuit 102 also includes a read amplifier 116 that receives read signals from the read/write device 59 , amplifies the read signals to generate the read signals r dx and r dy , and outputs the amplified read signals to the read channel circuit 100 .
The preamp circuit 102 provides a loopback mode during which the write amplifier 114 of the preamp circuit 102 is tested. In FIG. 3A , a switch 120 connects an output of the write amplifier 114 to an output of the read amplifier 116 . When the switch 120 is used, the read amplifier 116 is optionally turned off during the loopback mode to reduce noise in the system due to signals from the read/write head 59 . Turning off the read amplifier 116 may be accomplished by turning off or disconnecting a supply voltage, disconnecting the input of the read amplifier 116 from the read/write head and/or grounding the inputs of the read amplifier 116 .
As can be appreciated, other devices such as a multiplexer can be used by the loopback circuit. Referring now to FIG. 3B , a multiplexer 121 is used to connect the output of the write amplifier 114 to the read channel 100 . The multiplexer 121 also disconnects the output of the write amplifier 116 at the same time, which reduces noise.
Referring now to FIGS. 3A and 3B , a write enable signal (W) is generated by the read channel circuit 100 during a write operation. In one embodiment, the write enable signal controls the switch 120 or the multiplexer 121 . The output of the write amplifier 114 is looped back by the switch 120 or the multiplexer 121 to the read channel circuit 100 . In other words, the switch 120 or the multiplexer 121 connects the output of the write amplifier 114 to the read signal input of the read channel 100 . When the write enable signal is not asserted (e.g. during a read operation), the output of the write amplifier 114 is not looped back by the switch 120 or the multiplexer 121 to the read channel circuit 100 .
The first counter 104 generates a first count of the selected attribute of the write signal. The first count is output to the comparator 106 . The second counter 108 receives the amplified write signal that is looped back through the write amplifier 114 . The second counter 108 generates a second count of the attribute for the looped-back write signal. The second count is output to the comparator 106 . The comparator 106 compares a difference between the first and second counts to a threshold (Th).
If the difference between the first and second counts are less than or equal to the threshold, the comparator 106 outputs a first state. If the difference between the first and second counts are not less than or equal to the threshold, the comparator 106 outputs a second state. The first state corresponds to an operational preamplifier circuit. The second state corresponds to a non-operational preamplifier circuit. Faults and/or flags can optionally be generated when the comparator outputs the second state. As can be appreciated, testing of the preamp circuit 102 can be performed when the write enable signal is present. In addition, the testing can be performed at other intervals. For example, testing can be performed when the write enable signal is present during startup, periodically, randomly, during all write operations, in response to a particular event or events, or in any other suitable manner.
Referring now to FIG. 4 , a functional block diagram of a second exemplary read channel circuit 100 and preamp circuit 102 according to the present invention are shown. In FIG. 4 , both the write amplifier 114 and the read amplifier 116 are tested at the same time. When the write enable signal is present, the output of the write amplifier 114 is connected by a multiplexer 129 through an optional attenuator circuit 130 to an input of the read amplifier 116 . The attenuator circuit 130 attenuates the output of the write amplifier 114 if needed to prevent damage to the read amplifier 116 . The multiplexer 129 disconnects the input of the read amplifier 116 from the read/write head 59 .
Referring now to FIGS. 5 and 6 , functional block diagrams of third and fourth exemplary read channel circuits 100 and preamp circuits 102 are shown. The read channel circuits 100 and preamp circuits 102 in FIGS. 5 and 6 are similar to those shown in FIGS. 3 and 4 , respectively. However, instead of using the write enable signal to initiate the test, the preamp circuit 110 includes a trigger 140 that automatically triggers the loopback mode periodically when the write enable signal is present. For example, the trigger 140 can be triggered during startup when the write enable signal is present. The test enable signal that is generated by the trigger 140 remains high for a predetermined period during which the testing of the write amplifier 114 is performed. After the test is complete, the test enable signal goes low until the next startup. When the switch 120 is used in FIG. 5 , the read amplifier 116 is optionally turned off during the loopback mode to reduce noise in the system due to signals from the read/write head 59 . Turning off the read amplifier 116 may be accomplished by turning off or disconnecting a supply voltage, disconnecting the input of the read amplifier 116 from the read/write head and/or grounding the inputs of the read amplifier 116 .
Referring now to FIG. 7 , the read channel (RC) circuit 100 includes a RC encoding circuit 150 in the write path and a RC decoding circuit 152 in the read path. The read channel circuit 100 includes a data generator 160 that generates a test symbol that is encoded and transmitted as a write signal to the preamp circuit 102 . The write signal is amplified by the write amplifier 114 and looped back by the switch 120 during the loopback mode to the RC decoding circuit 152 . The RC decoding circuit 152 decodes the write signal and outputs a received symbol to a comparator 164 . As can be appreciated, a multiplexer may also be used.
The comparator 164 compares the received symbol to a delayed test signal. A delay element 166 can be used to delay the test symbol for an appropriate amount of time. As can be appreciated, a latch, a buffer or any other suitable device can alternatively be used to store the test symbol until the received symbol is received at the comparator 164 . If the received symbol and test symbol match, the comparator 164 outputs a first state. If the symbols do not match, the comparator 164 outputs a second state. The first state corresponds to an operational preamplifier circuit. The second state corresponds to a non-operational preamplifier circuit. Faults and/or flags can optionally be generated when the comparator outputs the second state. When the switch 120 is used in FIG. 7 , the read amplifier 116 is optionally turned off during the loopback mode to reduce noise in the system due to signals from the read/write head 59 . Turning off the read amplifier 116 may be accomplished by turning off or disconnecting a supply voltage, disconnecting the input of the read amplifier 116 from the read/write head and/or grounding the inputs of the read amplifier 116 .
Referring now to FIG. 8 , a hard drive control (HDC) circuit 170 includes a HDC write processing circuit 172 in the write path and a HDC read processing circuit 174 in the read path. The data generator 160 generates a test symbol that is output by the HDC 170 , encoded by the read channel circuit 100 and transmitted to the preamp circuit 102 . The write signal is amplified by the write amplifier 114 and looped back by the switch 120 during the loopback mode to the read channel circuit 100 where decoding occurs. The received symbol is output to the comparator 164 in the HDC 170 . As can be appreciated, a multiplexer can also be used.
The comparator 164 compares the received symbol to a delayed test signal. The delay element 166 can be used to delay the test symbol for an appropriate amount of time. As can be appreciated, a latch, a buffer or any other suitable device can alternatively be used to store the test symbol until the appropriate time. If the symbols match, the comparator 164 outputs a first state. If the symbols do not match, the comparator 164 outputs a second state. The first state corresponds to an operational preamplifier circuit. The second state corresponds to a non-operational preamplifier circuit. Faults and/or flags can optionally be generated when the comparator outputs the second state.
The data generator, delay, and comparator components can be located anywhere on the read/write path, integrated with any device located on the read/write path, located in a host, and/or located in any other suitable device. Skilled artisans will appreciate that the embodiments in FIGS. 5-8 may also be implemented using a multiplexer in a manner similar to FIGS. 3B and 4 . When the switch 120 is used in FIG. 3A , 5 and 7 , the read amplifier 116 is optionally turned off during the loopback mode to reduce noise in the system due to signals from the read/write head 59 . In one implementation, the signal that is used to initial the loopback mode can also be used to shut down the read amplifier 116 . Alternately, the signal that is used to initiate the loopback mode can be used to trigger the additional switches and/or multiplexers that are used to turn off the read amplifier 116 .
While the present invention has been described in conjunction with hard drives, skilled artisans will appreciate that the foregoing invention has application to any data storage device including hard disk drives, compact disk (CD) drives (write and/or read/write), digital video disk (DVD) drives (read and/or read/write), optical drives, and/or any other type of data storage device.
Those skilled in the art can now appreciate from the foregoing description that the broad teachings of the present invention can be implemented in a variety of forms. Therefore, while this invention has been described in connection with particular examples thereof, the true scope of the invention should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, the specification and the following claims. | A method for testing operation of a preamplifier circuit includes generating a first symbol, converting the first symbol into a write signal, transmitting the write signal to a write signal input of the preamplifier circuit, and looping the write signal back to a read signal output of the preamplifier circuit. | 6 |
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
[0001] This application is a Continuation of U.S. patent application Ser. No. 12/913,050 filed Oct. 27, 2010, which is a Divisional Application of U.S. patent application Ser. No. 11/469,248, filed Aug. 31, 2006 (now U.S. Pat. No. 7,873,780), which is a Continuation Application of U.S. patent application Ser. No. 10/449,485, filed May 29, 2003 (now U.S. Pat. No. 7,401,181), which claims priority from U.S. Provisional Patent Application No. 60/384,873, filed May 29, 2002, all of which are incorporated herein by reference in their entirety.
BACKGROUND
[0002] 1. Field
[0003] This invention relates generally to content addressable memory searching, and more particularly to a dispatch device capable of reusing comparand data for multiple searches without requiring a host processor to reload the comparand for each search operation.
[0004] 2. Description of the Related Art
[0005] In today's computer networks, data generally is divided into smaller quantities, known as packets, for transmission. Associated with each packet is a header, which includes information such as the origin of the packet and the packet's intended destination. The header is examined to classify and forward each packet through a network to its final destination, generally utilizing a content addressable memory (CAM) semiconductor device.
[0006] CAMs provide performance advantages over conventional memory devices having conventional memory search algorithms, such as binary or tree-based searches, by comparing the desired search term, or comparand, against the entire list of entries simultaneously, giving an order-of-magnitude reduction in the search time. For example, a binary search through a non-CAM based database of 1000 entries may tae ten separate search operations whereas a CAM device with 1000 entries may be searched in a single operation, resulting in significant time and processing savings. Internet routers often include a CAM for searching the address of specified data, allowing the routers to perform fast address searches to facilitate more efficient communication between computer systems over computer networks.
[0007] Conventional CAMs typically include a two-dimensional row and column content addressable memory core array of cells. In such an array, each row typically contains an address, pointer, or bit pattern entry. In this configuration, a CAM may perform “read” and “write” operations at specific addresses as is done in conventional random access memories (RAMs). However, unlike RAMs, data “search” operations that simultaneously compare a bit pattern of data against an entire list (i.e., column) of pre-stored entries (i.e., rows) can be performed.
[0008] Hence, a CAM allows the entire contents of the memory to be searched and matched instead of having to specify one or more particular memory locations in order to retrieve data from the memory. Thus, a CAM may be used to accelerate any application requiring fast searches of a database, list, or pattern, such as in database machines, image or voice recognition, or computer and communication networks.
[0009] Various algorithms are conventionally used to example the information contained in the header of a packet. For example, table-based algorithms can be implemented using CAMs. In this case, the entries of a CAM are preloaded with routing and other information, and the CAM is used as an associative array.
[0010] In operation, a CAM is presented with information, hereinafter referred to as a comparand, that it compares with information previously loaded into its entries. The action of comparing a comparand with information previously loaded into the CAM entries is referred to as a look-up or search operation. If the look-up or search operation is successful, a suitable result is returned. Otherwise the CAM indicates the look-up or search operation failed or “missed.”
[0011] In a typical CAM and host processor configuration, the host processor writes header information into the Dispatch Device, which then supplies the header information to the CAM. The CAM then performs the look-up or search operation and returns the results to the dispatch device, which collects the results and provides the results to the host processor.
[0012] Data is transmitted between the host processor and the dispatch device using a bus. However, the bus width, which is the number of wires that connect the host processor to the dispatch device, is usually much less than the number of bits in the header data to be applied to the CAM as a comparand. As a result, when using a CAM that performs look-up or search operations very quickly, the time to transfer comparand information from the host processor to the dispatch device may be a significant performance bottleneck.
[0013] A header for a packet is a sequence of bits, wherein different groups of bits are utilized for different purposes. Hence, to properly classify and forward a packet, several look-up operations may be required on portions of the header. If the entire header must be re-written by the host processor into the Dispatch Device for each look-up or search operation required on a packet, the time required to classify and forward each packet can significantly affect the speed of the routing equipment.
[0014] In view of the foregoing, there is a need for systems and methods for that reduce the number of times a comparand must be written to a dispatch device. The methods should allow a comparand to be reused for multiple search operations when appropriate. In addition, when a now comparand varies from a previous comparand by very little, the method should allow the stored comparand to be slightly altered and reused to avoid requiring another comparand write to the dispatch device.
SUMMARY
[0015] Broadly speaking, the present invention fills these needs by providing a device capable of using a comparand, or portions of a comparand, for multiple look-up or search operations in various tables within a CAM without requiring a host processor to reload any portion of the comparand for successive look-up or search operations. In one embodiment, a dispatch device for providing a comparand to a CAM is disclosed. The dispatch device includes a comparand data register that is capable of storing a comparand. Associated with the comparand data register, is a plurality of result registers. In operation, the comparand is provided as input data to the CAM for a plurality of search operations. For each search operation, the result is stored in one of the plurality of result registers. In one aspect, the dispatch device can include comparand overlay logic that alters selected bits of the comparand prior to providing the comparand to the CAM. In this aspect, the comparand overlay logic copies the comparand to a temporary comparand memory prior to altering selected bits of the comparand stored in the temporary comparand memory. The comparand overlay logic receives a comparand overlay pointer indicating particular bits within the comparand to modify, and a comparand overlay data value indicating data to write to the particular bits indicated by the comparand overlay pointer. The dispatch device also can include sub-comparand logic that selects a portion of the comparand, which can be provided to the CAM for a search operation. In this aspect, the sub-comparand logic copies the portion of the comparand to a temporary comparand memory prior to providing the sub-comparand stored in the temporary comparand memory to the CAM for a search operation. The sub-comparand logic receives a sub-comparand pointer indicating a most significant nibble of the portion of the comparand within the comparand, and a sub-comparand size value indicating a size of the portion of the comparand. Optionally, the dispatch device can include a plurality of context registers, with each context register including a comparand data register and a plurality of result registers associated with the comparand data register.
[0016] In an additional embodiment, a method is disclosed for providing a comparand to a CAM. The method includes receiving a comparand and storing the comparand in a comparand data register. The comparand is provided to a CAM for use in a search operation, and a result is received from the CAM. The result is stored in one of a plurality of result registers associated with the comparand data register. In this manner, additional searches can be performed using the comparand stored in the comparand data register, with a result for each search operation stored in one of the plurality of result registers. In one aspect, the method can include receiving a comparand overlay pointer indicating particular bits within the comparand to modify, and receiving a comparand overlay data value indicating data to write to the particular bits indicated by the comparand overlay pointer. In this aspect, the comparand can be copied to a temporary comparand memory, and a value located at a position in the comparand stored in the temporary comparand memory indicated by the comparand overlay pointer can be replaced with the comparand overlay data value. Optionally, a sub-comparand pointer indicating a most significant nibble of a portion of the comparand can be received along with a sub-comparand size data value indicating a size of a sub-comparand. The portion of the comparand having a most significant nibble indicated by the sub-comparand pointer and a size indicated by the sub-comparand size data value is copied to a temporary comparand memory for use in search CAM operations.
[0017] A system for providing a comparand to a CAM is disclosed in a other embodiment of the present invention. The system includes a host processor, a CAM, and a dispatch device in communication with the host process and the CAM. The dispatch device includes a plurality of context registers for use with individual processing threads. Each context register includes a comparand data register capable of storing a comparand and a plurality of result registers associated with the comparand data register. The host register ran store a comparand in a selected comparand data registers which can be utilized for a plurality of search operations in the CAM. A result for each search operation is stored in one of the plurality of result registers associated with the selected compared data register. As above, the dispatch device can include comparand overlay logic that alters selected bits of the comparand prior to providing the comparand to the CAM. The dispatch device can also include sub-comparand logic that selects a portion of the comparand, which can be provided to the CAM for a search operation. Other aspects and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The invention, together with further advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings in which:
[0019] FIG. 1 is a block diagram showing a CAM and host processor configuration, in accordance with an embodiment of the present invention;
[0020] FIG. 2 is a block diagram showing a dispatch device having comparand reuse capabilities, in accordance with an embodiment of the present invention;
[0021] FIG. 3 is a block diagram showing an example of using a comparand overlay operation to perform table selection, in accordance with an embodiment of the present invention; and
[0022] FIG. 4 is a block diagram showing an example of using a sub-comparand operation, in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION
[0023] An invention is disclosed for a using a comparand, or portions of a comparand, for multiple look-up or search operations in various tables within a CAM without requiring a host processor to reload any portion of the comparand for successive look-up or search operations. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order not to unnecessarily obscure the present invention.
[0024] FIG. 1 is a block diagram showing a CAM and host processor configuration 100 , in accordance with an embodiment of the present invention. As illustrated in FIG. 1 , the CAM and host processor configuration 100 includes a CAM 106 coupled to a dispatch device 104 , which is a device utilized to dispatch look-up or search operations from a host processor 102 to the CAM 106 . In operation, the host processor 102 typically writes header information into the Dispatch Device 104 , which then supplies the header information to the CAM 106 . The CAM 106 then performs the look-up or search operation and returns the results to the dispatch device 104 , which collects the results and provides the results to the host processor 102 .
[0025] Data is transmitted between the host processor 102 and the dispatch device 104 using a bus 108 . However, as mentioned previously, the bus width is usually much less than the number of bits in the header data to be applied to the CAM 106 as a comparand. As a result, when using a CAM 106 that performs look-up or search operations very quickly, the time to transfer comparand information from the host processor to the dispatch device may be a significant performance bottleneck.
[0026] To address this issue, embodiments of the present invention provide a dispatch device capable of using a comparand, or portions of a comparand, for multiple look-up or search operations in various tables within a CAM without requiring a host processor to reload any portion of the comparand for successive look-up or search operations. FIG. 2 is a block diagram showing a dispatch device 104 having comparand reuse capabilities, in accordance with an embodiment of the present invention. The dispatch device 104 includes a plurality of context registers 200 a - 200 c. Each context register includes a comparand data register 202 and a plurality of associated result registers 204 . Although FIG. 2 illustrates only three context registers 200 a - 200 c, in should be noted that the dispatch device 104 can include any number of context registers 200 a - 200 c. Similarly, although FIG. 2 illustrates only four result registers 204 associated with each comparand data register 202 , any number of result registers 204 can be associated with each comparand data register 202 .
[0027] The dispatch device 104 provides an efficient mechanism that allows the host processor's multiple processing threads to efficiently perform look-up operations, using a pipelined architecture and dedicated registers for each processing thread. To perform a look-up operation, the host processor transfers a comparand to the dispatch device 104 . The dispatch device 104 stores the comparand in a comparand data register 202 of a particular context register 200 a - 200 c. After performing the lookup operation using an associated CAM, the dispatch device 104 stores the results of the operation in a results register 204 associated with the comparand data register 202 . The look-up operation is completed when the host processor receives the contents of the result register 204 from the dispatch device. When performing a look-up operation, the host processor transfers the comparand to a particular comparand data register 202 and selects a result register 204 that will store the results.
[0028] The host process can access the comparand data registers 202 and result registers 204 on the dispatch device using various techniques. For example, each comparand data register 202 and result register 204 can be accessed via a memory-mapped interface to which the host processor can read and write. Another example is a request-response interface where the host processor identifies a comparand data register 202 using a unique identifier when initiating a look-up operation and the results are returned to the host processor using the same identifier when the dispatch device 104 completes the look-up operation.
[0029] Generally, each context register 200 a - 200 c should be dedicated to a single processing thread in the host processor. However, a single processing thread may use more than one context register 200 a - 200 c. Once a comparand is loaded into a comparand data register 202 , the comparand can be used for successive look-up or search operations without having to reload the comparand. Since each context register 200 a - 200 c has n result registers 204 , the host processor can dispatch up to n lookup operations for a single comparand without having to wait for the results or load the comparand multiple times. As a result, over-all system performance is improved.
[0030] For example, in the exemplary embodiment of FIG. 2 , the host processor can load a comparand into comparand data register 0 202 of context register 200 a. The host processor then dispatches a look-up operation specifying that the results should be stored in result register 0 204 associated with comparand data register 0 202 of context register 200 a. The host processor can then dispatch up to three more searches by requesting the dispatch device 104 to use the comparand stored in comparand data register 0 202 of context register 200 a and store the results in result registers 1 to 3 of context register 200 a.
[0031] It is desirable for the host processor to modify plan of the comparand when issuing look-up and search commands using, the same comparand data register 202 . Embodiments of the present invention allow the host processor to overlay (temporarily replace) any portion of the comparand for a look-up or search operation. This allows, the host processor to issue up to a look-up or search operations using the contents of one comparand data register 202 with effectively n different comparands. Reusing the contents of one comparand data register 202 for a plurality of different look-up and search operations significantly reduces the bus transactions between the host processor and the dispatch device 104 , and thus increases the look-up through-put of the system.
[0032] One application for a comparand overlay is storing multiple tables in the CAM and searching for the same comparand in two or more of the tables. In this case, the overlay byte acts as a “table selector,”. Another application is searching for two comparands in the same table that differ by a few bits.
[0033] In one embodiment, the host processor provides two sets of data to the dispatch device 104 : a comparand overlay pointer and a comparand overlay nibble. The comparand overlay pointer specifies a specific nibble, which is one or more data bits, within a comparand data register 202 . The comparand overlay nibble is the data that will replace the appropriate nibble of the comparand data register 202 for look-up or search operations. This allows the host processor to overlay any nibble of the comparand data register 202 and issue a look-up or search operation without having to reload the comparand. It should be borne in mind that the comparand overlay pointer does not need to point to a nibble comprising multiple data bits. For example, the comparand overlay pointer can point to any arbitrary bit of the comparand. Similarly, the comparand overlay nibble does not have to be a nibble, that is, the comparand overlay nibble can be any arbitrary number of bits.
[0034] When overlaying a nibble within the comparand data register 202 , the content of the comparand data register 202 does not require alteration. In one embodiment, the overlay is performed on a temporary copy of the comparand data register 202 in the dispatch device 104 to preserve the comparand transferred by the host processor. This allows the host processor to dispatch multiple searches using the one comparand data register 202 .
[0035] For example, FIG. 3 is a block diagram showing an example of using a comparand overlay operation to perform table selection, in accordance with an embodiment of the present invention. In a CAM, every entry is compared against the applied comparand. In order to have separate tables for different table-based algorithms in a CAM, a portion of every entry in the CAM is assigned a table identifier. To select a particular table, the applied comparand indicates the desired table identifier in its corresponding bits.
[0036] For example, if there are to be nine tables of 36-bit entries stored in a CAM, then four bits of each entry are dedicated as a table identifier. In the example of FIG. 3 , the least significant four bits of each entry are encoded with the hexadecimal values: 0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, and 0x8, depending upon which table the entry is to be associated with. When the comparand is loaded into the comparand data register 202 , the least significant four bits of the 36-bit value can be written with any one of the table identifier values. In tills manner, only the CAM entries of the corresponding table can possibly match the comparand because CAM entries in other tables will have a different least significant four bits.
[0037] To look-up an entry in the table that has entries with the table identifier 0x5, the host processor sets the comparand overlay point to 8 302 ′ and the comparand overlay data to 0x5 in the dispatch device. When the look-up operation is initiated, the dispatch device creates a temporary copy 300 of the comparand 302 . The dispatch device then replaces the bits at nibble offset 8 302 ″, which is the least significant nibble of the temporary comparand copy 300 , with 0x5. The temporary comparand copy 300 is then utilized to search the CAM array. It should be noted that it is not necessary for the least significant nibble of an entry to be assigned as the table identifier. The table identifier can reside in any nibble.
[0038] It is also desirable for the host processor to perform look-up and search operations using only a portion of a comparand. Embodiments of the present invention utilize a mechanism, referred to as a sub-comparand, to allow the host processor to select a portion of the comparand data register to utilize for a look-up or search operation. In this manner, the host processor can more efficiently store tables in the CAM array and improve the system throughput by reducing the amount of data transfers between the host processor and the dispatch device.
[0039] For example, without the sub-comparand feature, to look-up a 36-bit quantity in the middle of a 144-bit comparand would require a table of 144-bit entries, or, the host processor would have to use a different comparand data register for the 36-bit search. The sub-comparand feature of the embodiments of the present invention allows the host processor to look-up the 36-bit quantity in 36-bit tables thus significantly reducing the number of words required for a table and removes the need for the host processor to use a different comparand data register.
[0040] In one embodiment, the host processor provides two sets of data to the dispatch device for sub-comparand operations: a sub-comparand pointer and a sub-comparand size. The sub-comparand pointer identifies the most-significant nibble in the comparand data register that will be become the most significant nibble of the comparand used for the look-up or search operation. The sub-comparand size indicates the size of the sub-comparand that will be used for the look-up or search operation. It should be borne in mind that the sub-comparand pointer does not need to point to, a nibble. For example, the sub-comparand pointer can point to any arbitrary bit of the comparand. Similarly, the sub-comparand size does not have to be a nibble, that is, the sub-comparand size can be any arbitrary number of bits.
[0041] When using a sub-comparand within the comparand data register, the content of the comparand data register does not require alteration. In one embodiment the sub-comparand selection is performed using a temporary copy of the comparand data register in the dispatch device to preserve the comparand transferred by the host processor. This allows the host processor to dispatch multiple searches using the one comparand data register.
[0042] For example, FIG. 4 is a block diagram showing an example of using a sub-comparand operation, in accordance with an embodiment of the present invention. In the example of FIG. 4 , the comparand data register 202 includes a 72-bit hexadecimal quantity 0x112233445566778899. To perform a look-up operation using the 36-bit hexadecimal sub-comparand 0x334455667, the host processor provides a sub-comparand pointer value of 4 and a sub-comparand size of 36. In this example, the dispatch device will select the sub-comparand having the most significant nibble starting at nibble 402 at office +4, and having a size of 36-bits. This generates the sub-comparand 400 , which can be utilized for lookup operations in tables of 36-bit entries.
[0043] Although the foregoing invention has been described in some detail, for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the appended claims. Accordingly, the present embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims. | A method includes searching a content addressable memory based on a comparand. The comparand includes a collection of bits. A modified comparand is generated by modifying the comparand. The modified comparand is based at least in part on a comparand overlay data value. The content addressable memory is also searched with the modified comparand. | 6 |
FIELD OF THE INVENTION
The present invention relates to window covering assemblies and to cord lock units for use in such assemblies.
BACKGROUND OF THE INVENTION
Existing window coverings such as horizontal blind assemblies, commonly known as Venetian blinds, comprise a header means or channel with a plurality of blind slats suspended therefrom. Spaced apart pull cords extend downwardly from the header channel through openings in the blind slats and are secured to the lowermost slat. Such cords can then be use for raising and lowering the slats.
Additionally, such blind assemblies are generally provided with slat-rotating cords by means of which the slats can be rotated about longitudinal axes between closed and open positions.
Certain forms of window coverings assemblies such as vertically moveable drapes are similarly provided with spaced apart pull cords for raising and lowering.
The pull cords for raising and lowering such window coverings generally pass through the header channel and then hang from one end of that channel as a control loop so that a user can adjust the vertical position of the drapes, slats or the like. Within the header channel, such cords normally pass through a cord lock unit for releasably clamping the pull cords so in turn to hold the blind slats or drapes in any desired horizontal position and to prevent them falling under the effect of gravity to their lowermost position.
Such a cord lock unit is normally provided in the header channel at the position at which the control loop exits that channel. The mechanism provided in such a cord lock unit for releasably clamping the pull cords generally operates in a manner determined by the angular position of the pull cord control loop relative to the header channel. For example, by pulling the control loop in one direction and then allowing the pull cords to raise slightly as a result of the drapes or blind slats falling under the effect of gravity, some form of clamping roller or other mechanism is caused to move into a cord-clamping position. On the other hand, if the control loop is pulled a short distance in a different angular direction relative to the header channel, such a clamping roller or other mechanism is released and moves into a position in which it no longer engages the pull cords.
Various cord lock units and blind assemblies incorporating such units are described in U.S. Pat. Nos. 2,449,583, 2,480,993, 2,529,229, 2,587,752, 2,731,111, 2,781,091, 2,781,836, 2,786,551, 3,221,802 and 4,487,243.
In manufacturing a drape or horizontal blind assembly incorporating a cord lock unit as already known, it has generally been necessary to secure the cord lock unit internally within the header channel and then to pass the pull cords through that unit. This manufacturing operation is both difficult in view of the limited space within the header channel and is, therefore, both time-consuming and expensive.
In some cases it is desirable to be able to remove the cord lock unit for servicing. In most such prior art card lock designs, this is difficult and usually results in damage to the cord lock unit.
SUMMARY OF THE INVENTION
In an attempt to minimize the aforementioned problems, the present invention provides a cord lock unit through which the pull cords can be threaded with the cord lock unit separate from the header channel. Having so threaded the cords through the cord lock unit, the cord lock unit can then simply be inserted through an opening in the header channel and locked in position in that channel by a locking means provided for such purpose.
Broadly, the invention provides a cord lock unit for use with a window covering assembly which comprises a hollow channel-shaped header unit defined by a plurality of outer walls, defining an interior and an exterior, a pair of mutually spaced apart pull cords, extending upwardly into the header unit, along the interior of the head unit and downwardly from the header unit through an opening in at least one of the walls of said header unit to the exterior, and such opening being defined by a peripheral edge, and which cord lock unit comprises a first exterior portion larger than the opening in the header unit, a second interior portion secured to the first portion and dimensioned so as to be insertable through the opening in the header unit with the first extending outwardly beyond the peripheral edge of the opening, resilient engagement means adapted to be deflected during insertion of the second portion through the opening to permit such insertion and resiliently to return to a position after such insertion so as then to retain the cord lock unit in position within the opening by resilient engagement; cord being disengageable for removal of said cord lock unit; pulley means for guiding the pull cords for movement through the cord lock unit, and, releasable cord-engaging means movable between a cord-engaging position and a cord-releasing position for engaging the cords in the cord-engaging position to prevent movement thereof and for permitting movement of the cords in the cord-releasing position.
In one embodiment of this invention, the first portion of such a cord lock unit comprises a lower outer exterior portion, the second interior portion comprises a smaller upper inner portion and the resilient engagement means are provided on the upper inner portion so as to be deflected during insertion of the inner portion upwardly through the opening to permit such insertion and resiliently to return to a position after such insertion so as then to retain the cord lock unit in position within the opening by engagement of the resilient engagement means with the header unit internally thereof and outwardly of the peripheral edge of the opening.
In another embodiment of this invention, such a cord lock unit comprises an upper inner portion, a lower outer portion having resilient engagement means and adapted to be deflected during insertion downwardly through the opening to permit such insertion and resiliently to return to a position after such insertion so as then to retain the cord lock unit in position within the opening by engagement with the header unit externally thereof and outwardly of the peripheral edge of the opening.
The releasable cord-engaging means is a cord lock unit in accordance with this invention will normally be one which can be moved between its cord-engaging position and its cord-releasing position by varying the angular position of the cords relative to the header unit.
In one particular embodiment, the aforementioned releasable cord-engaging means comprises a roller having an externally ribbed cylindrical surface and a cooperating ribbed ramp whereby, when the cords are in a predetermined angular position relative to the header unit, such cords engage the roller so that, on upward movement of the cords, they cause rotation of the roller and in turn upward movement of the roller along the ramp until the cords are engaged between the roller and the pulley so then to prevent further movement of the cords whereas, when the cords are not in such predetermined angular position, upward movement of the cords does not cause upward movement of the roller along the ramp.
The resilient engagement means provided in a cord lock unit in accordance with this invention preferably comprises a pair of opposed resilient fingers.
The first and second portions of a cord lock unit in accordance with this invention are preferably integrally formed of a plastics material.
The first and second portions of a cord lock unit are, in accordance with one feature of this invention, preferably shaped so as to permit insertion of the second portion into an opening formed in two mutually perpendicular and adjacent walls of the header unit.
The invention also embraces a drape or blind assembly including a cord lock unit as already defined.
The various features of novelty which characterize the invention are pointed out with more particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described merely by way of illustration with reference to the accompanying drawings, in which:
FIG. 1 is a somewhat schematic perspective illustration of one embodiment of a horizontal window covering assembly in accordance with this invention and incorporating a cord lock unit as also provided by this invention;
FIG. 2 is a perspective illustration on a larger scale of the cord lock unit shown in FIG. 1 and also showing separate therefrom a portion of a header channel of the blind assembly;
FIG. 3 is a longitudinal sectional view through the cord lock unit of FIG. 2 in position in the header channel when taken as indicated by the arrows 3--3 of that figure and showing the internal parts of that unit in a cord-releasing position;
FIG. 4 is a longitudinal sectional view similar to that of FIG. 3 but showing the internal parts in a cord-engaging position;
FIG. 5 is a fragmentary transverse sectional view when taken as indicated by the arrows 5--5 of FIG. 3; and
FIG. 6 is a longitudinal sectional view similar to that of FIG. 4 but showing an alternative embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring first to FIG. 1 of the accompanying drawings, it will be seen that there is indicated generally at 10 therein a window covering, in this case a horizontal blind assembly including a header unit or channel generally indicated at 12 and comprising a base wall 14 and two upstanding and mutually spaced apart side walls 16 and 18 and defining an interior and exterior.
A plurality of horizontal blind slats 20 are suspended, in a manner yet to be described, below the header channel 12, the lowermost such slat being indicated by the legend 22. Mutually spaced apart suspension pull cords 24 and 26 extend downwardly through openings 28 in the slats 20 and are secured at their lower ends to anchoring buttons 27 secured in openings in the lowermost slat 22. It will be appreciated that other window coverings such as Russian drapes, balloon drapes and the like, also make use of similar pull cords for raising and lowering the drapes and are included within the scope of the invention.
Within the header channel 12, the pull cords 24 and 26 pass over pulleys 30 and 32 respectively and extend horizontally to a cord lock unit indicated generally at 34 and to be described in greater detail as the description herein proceeds. From the cord lock unit 34, the pull cords 24 and 26 hang outwardly and downwardly and are used for raising and lowering the blind slats 20. It will be understood that the cords 24 and 26 may be integrally formed from a single length of cord so as in fact to provide what might be referred to as a control loop.
The Venetian blind assembly 10 of the embodiment as illustrated also comprises suspension and slat-rotation tapes or cords 36, 38, 40 and 42 interconnected in a known manner by rungs 43. The cords 36 and 38 pass the slats 20 at opposite edges thereof at essentially the same longitudinal position as the pull cord 24. Similarly, the cords 40 and 42 pass the slats 20 at opposite edges thereof at essentially the same longitudinal position as the pull cord 26.
In accordance with well known practice in the manufacture of Venetian blinds, the cords 36, 38 and 40, 42 are wound around a transverse tilt rod (not shown) rotatably mounted in the header channel. Rotation of the tilt rod will, in a manner well known per se, cause tilting of the slats one way or the other.
The rungs 43 support the slats 20 so that, as the cords 36 and 40 are raised and the cords 38 and 42 are lowered, the slats 20 are tilted into their closed position. Similarly, then the cords 36 and 40 are lowered and the cords 38 and 42 are raised, the slats 20 are tilted into their open positions.
In accordance with well known practice, a rotatable wand 44 is provided at one end of the header channel 12 on rotation of that wand 44, such cords 36, and 40 are caused so to be raised and cords 38 and 42 are lowered and vice versa. Any other suitable mechanism such as a pulley and chain (not shown) can be provided for causing such movement of the cords 36, 38, 40 and 42. Since the means by which opening and closing of the slats 20 is effected well known and forms no part of the present invention, such mechanism will not be described in greater detail herein.
While the preceding description has been directed to the structure and operation of a horizontal blind assembly, it should be understood that a cord lock unit, such as the cord lock unit 34, can also be used in a drape assembly in which drapes are moved between raised and lowered positions by means of pull cords such as Russians, and balloons.
The structure of the cord lock unit 34 will now be described in greater detail with reference to FIGS. 2 to 5 of the drawings. The cord lock unit 34 comprises a lower outer portion generally indicated at 46 and an upper inner portion generally indicated at 48. After the cord lock unit 34 has been installed in an opening generally indicated at 49 in the header channel 12, the outer portion 46 is disposed outwardly of the header channel 12 while the inner portion 48 is disposed actually within that channel 12.
As will best be understood by reference to FIG. 2, the opening 49 comprises aligned openings in the base 14 and the side wall 18 of the header channel 12. The length of the opening 49 is shown in FIG. 2 as having a value "L" and such opening 49 is shown as extending distances "H" and "W" from the corner 50 between the base 14 and the side wall 18 into wall 18 and base 14 respectively. The periphery of the opening 49 is indicated generally by the legend 51.
The inner portion 48 of the cord lock unit 34 comprises spaced apart longitudinal side walls 52 and 54 having inner edges 55 and which are integrally formed with angularly disposed longitudinal side walls 56 and 58 respectively of the outer portion 46. The side walls 56 and 58 are mutually perpendicular and meet at a corner 60.
When the cord lock unit 34 is disposed within the opening 49 in the header channel 12, the side wall 58 extends upwardly along the side wall 18 of the header channel 12 while the side wall 56 extends horizontally across the base 14 of the header channel 12. From FIG. 2, it will be seen that the side walls 56 and 58 extend beyond the side walls 52 and 54 respectively to provide shoulders 62 and 64 respectively. Additionally, it will be noted that the side walls 56 and 58 each have a length M and are slightly longer than the side walls 52 and 54 to provide extensions 66. It will also be understood that the length M of each of the side walls 56 and 58 is greater than the length L of the opening 49.
As will best be understood by reference to FIG. 5, the side walls 56 and 58 of the outer portion 46 have widths K, X respectively greater than the aforementioned dimensions W, H respectively so that, when the cord lock unit 34 is disposed within the opening 49 in the header channel 12, those side walls 56, 58 extend beyond the periphery 51 of the opening 49. Similarly, the extensions 66 extend outwardly beyond the periphery 51 of the opening 49.
The side walls 52 and 54 of the inner portion 48 are connected at one end of the cord lock unit 34 by an end strap 68 which is integrally formed with a resilently flexible tongue 70. At their opposite ends, the side walls 52 and 54 are interconnected by an end strap 72 also integrally formed with a resiliently flexible tongue indicated at 74. A pulley roller 76 is rotatably mounted on a shaft 78 supported in the side walls 52 and 54 in proximity to the end strap 72. It is to be noted that the end strap 72 is disposed slightly outwardly relative to the inner edges 55 of the side walls 52 and 54 to permit the pull cords to pass freely to the pulley roller 76.
The side walls 52 and 54 are also integrally formed with a ramp member 80 which extends from a position in proximity to one end of the outer portion 46 both inwardly to the inner edges 55 of those longitudinal walls and longitudinally toward the opposite end of the cord lock unit 34. The downwardly facing surface of the ramp member 80 is formed with a plurality of transverse ribs 82.
Also disposed within the cord lock unit 34, there is provided a generally cylindrical floating roller 84 formed on its peripheral surface with a plurality of ribs 86 extending in a direction parallel to the axis of that roller. Elongated openings 88 are provided in the side walls 56 and 58 and a retaining pin 90 extends between the two ends of the cord lock unit 34 generally in alignment with the corner 60. The floating roller 84 has such a length that it is free to move in any radial direction between the side walls 52 and 54 and is prevented from passing through the openings 88 by the retaining pin 90.
In accordance with a particularly preferred feature of this invention, metallic plates 92, shown fragmentarily in FIG. 2 and only in that figure are provided on the internal surfaces of the side walls 52 and 54 to reduce friction and so to permit the floating roller 84 to move more freely within the cord lock unit 34. Such metal plates 92 also serve to reduce frictional wear of the side walls 52 and 54 as could be caused by movement of the cords 24 and 26 across those side walls.
Having described the construction of the cord lock unit 34, the manner in which it functions will now be briefly reviewed. If the free hanging ends of the pull cords 24 and 26 are pulled to raise the blind slats 20 with those cords angularly disposed as shown in phantom outline in FIG. 3 and then tension on the cords is released slightly to allow the slats to fall a short distance under the effect of gravity, engagement of the cords 24 and 26 with the floating roller 84 will cause that roller to engage the ramp 80 and the resulting rotation of the roller will in turn cause it to move upwardly along that ramp by virtue of the engagement of the ribs 86 on the roller 84 with the ribs 82 on the ramp 80. Such upward movement will continue until the floating roller 84 is in the position shown in FIG. 4 in which it serves to clamp the cords 24 and 26 between the pulley roller 76 and the floating roller 84. This then prevents any further upward movement of the cords 24 and 26 and consequently any further lowering of the blind slats 20.
When it is desired to lower the blind slats 20, the cords 24 and 26 are positioned in the angular position shown in solid lines in FIG. 3 and in FIG. 4 and pulled a slight distance downwardly. Such downward movement of the cords releases the floating roller 84 from its engagement with the ramp 80 and allows that roller 84 to fall into the position shown in FIG. 3. This in turn allows the blind slats 20 to be lowered.
In assembling the blind assembly 10, the pull cords 24 and 26 passing outwardly through the opening 49 in the header channel are passed through the cord lock unit 34 so as to be disposed between the pulley roller 76 and the floating roller 84. It has been found to be advantageous to have the cords 24 and 26 extend through the cord lock unit 34 on opposite sides of the retaining pin 90.
With the pull cords 24 and 26 so threaded through the cord lock unit 34, the inner portion 48 of that unit is then inserted into the opening 49 in the header channel 12. During such insertion, the flexible tongues 70 and 74 engage the peripheral end edges of the opening 49 and are flexed toward each other to allow continued insertion of the unit. When the unit 34 has been inserted to its final position as shown in FIGS. 3, 4 and 5, the tongues are disposed inwardly of the peripheral edges of the opening 49 and resiliently flex outwardly to the positions shown in FIGS. 3 and 4 so as then to engage the inner surfaces of the side wall 18 and the base 14 of the header channel 12 thereby retaining the cord lock unit 34 in position within the opening 49.
The alternative embodiment of a cord lock unit in accordance with this invention as generally indicated at 94 in FIG. 6 of the drawings is similar to the unit 34 already described and, to avoid undue duplication of the description herein, identical components of the two units will be identified by the same legends.
The cord lock unit 94 differs from the unit 34 in that it is designed to be inserted downwardly into an opening, corresponding to the opening 49, comprising aligned openings in the base 14 and the side wall 18 of the header channel 12.
The cord lock unit 94 comprises a body defining side walls 94a and end walls 94b, and having a first or upper inner portion generally indicated at 96 and a second or lower outer portion generally indicated at 98. After the cord lock unit 94 has been inserted in the opening in the header channel 12, the outer portion 98 is disposed outwardly of the header channel while the inner portion 96 is disposed actually within that channel 12.
The unit 94 comprises two resiliently flexible tongues 100 generally centrally located at opposite ends thereof and which are integrally formed with the inner portion 96 and on their outer surfaces with shoulders 102. The inner portion 96 is also provided with abutment members 104. During downward insertion, the tongues 100 flex toward each other and, after such insertion, resiliently return to the positions shown in FIG. 6 so that the shoulders 102 then engage the respective outer surfaces of the header channel 12 with the abutment members 104 abutting the respective inner surfaces of the header channel.
It will be understood that, in this particular embodiment of a cord lock unit in accordance with this invention, the flexible tongues constitute the resilient engagement means while the outer ends of those tongues constitute the outer portion 98.
The foregoing is a description of a preferred embodiment of the invention which is given here by way of example only. The invention is not to be taken as limited to any of the specific features as described, but comprehends all such variations thereof as come within the scope of the appended claims. | A cord lock unit is provided for use in a drape assembly having vertically movable drapes or in a horizontal blind assembly having a plurality of horizontal blind slats suspended from a header unit for vertical movement. Such assemblies comprise a pair of spaced apart pull cords for moving such drapes or blind slats vertically. The cord lock unit is designed so that it can be inserted into an opening in a header unit of such an assembly. Such a cord lock unit comprises a first portion larger than the opening in the header rail and a second portion secured to the first portion and dimensioned so as to be insertable through such opening. The unit also comprises resilient engagement means adapted to be deflected during insertion of the second portion to permit such insertion and resiliently to return to a position after such insertion so as then to retain the cord lock unit in position within the opening. | 4 |
CROSS-REFERENCE
The present application is based on and claims priority to Korean Patent Application No. 10-2003-0073531 filed in the Korean Intellectual Property Office on Oct. 21, 2003, the entire contents of which are incorporated herein by reference.
FIELD OF THE INVENTION
The present invention relates to MgO pellets used for providing a protective layer for a plasma display panel, and also to a plasma display panel using such pellets whereby the discharge delay time is minimized.
BACKGROUND OF THE INVENTION
Generally, a plasma display panel (referred to hereinafter simply as a “PDP”) is a display device which displays images with phosphors excited by the plasma discharge. When voltages are applied to the electrodes arranged within the discharge space of the PDP, a plasma discharge is generated between the electrodes and generates ultraviolet rays. The ultraviolet rays excite the phosphors with a predetermined pattern, thereby displaying the desired images.
A PDP is generally classified as an AC-type, a DC-type or a hybrid-type. FIG. 4 is an exploded perspective view of a discharge cell for a common AC-type PDP. As shown in FIG. 4 , the PDP 100 includes a bottom substrate 111 , a plurality of address electrodes 115 formed on the bottom substrate 111 , a dielectric layer 119 formed on the bottom substrate 111 over the address electrodes 115 , a plurality of barrier ribs 123 formed on the dielectric layer 119 and phosphor layers 125 formed between the barrier ribs 123 . The barrier ribs maintain the discharge distance and prevent cross talk between the cells.
A plurality of discharge sustain electrodes 117 are formed on the lower surface of a top substrate 113 facing the bottom substrate 111 and spaced apart from the address electrodes 115 formed on the bottom substrate 111 . The address electrodes are oriented perpendicular to the sustain electrodes. A dielectric layer 121 and a protective layer 127 sequentially cover the discharge sustain electrodes 117 on the side opposite the top substrate. While other materials may be used, the protective layer 127 is often formed of MgO.
The MgO protective layer is a transparent thin film, which reduces the effect of the ion collision caused by the discharge gas during operation, thereby protecting the dielectric layer. The MgO layer also emits secondary electrons so that the discharge voltage is lowered. The MgO protective layer is generally formed on the dielectric layer to a thickness of 3000-7000 Å. The MgO protective layer is generally formed using a sputtering method, electron beam deposition, ion beam assisted deposition (IBAD), chemical vapor deposition (CVD), or a sol-gel method. Recently, an ion plating method has been developed and has been used to form a MgO protective layer.
With regard to the electron beam deposition method, electron beams accelerated by electromagnetic fields collide against the MgO deposition material in order to heat and vaporize it, thereby forming a MgO protective layer. Although the sputtering method is preferred over the electron beam deposition method because the resulting protective layer is more densely formed with favorable crystalline alignment, the production costs are unfavorably high For the sol-gel method, the MgO protective layer is formed from a liquid phase.
As an alternative to these various methods for forming a MgO protective layer, an ion plating method has been recently developed. In the ion plating method, vaporized particles are ionized and form a target layer. Although the ion plating method is similar to the sputtering method with respect to the adhesion and crystallinity of the MgO protective layer, there is an advantage in that it is capable of rather high speed deposition at 8 nm/s.
According to such a processes, single crystal of MgO or sintered MgO is used. However, it is difficult to control the suitable amount of a specific dopant due to the difference of the solid solution limit in cooling process to manufacture a single crystal of MgO. Namely, a specific dopant for controlling the quality of MgO layer is precipitated without being solved in a single crystal of MgO during cooling process. For this reason, the MgO protective layer is generally formed by the ion plating method using a sintered MgO combined with a suitable amount of an appropriate dopant. Pellet-shaped materials may be used to deposit the MgO protective layer. The dissolution speed of the MgO generally depends upon the size and the shape of the pellets. Therefore, various attempts have been made to optimize the size and the shape of the MgO pellets.
SUMMARY OF THE INVENTION
In one embodiment of the present invention, MgO pellets with improved physical properties are provided and used for forming a MgO protective layer for a PDP. The use of such MgO pellets in forming a PDP protective layer enhances the discharge quality of the PDP.
In one embodiment of the present invention, the PDP includes first and second substrates facing each other. A plurality of first and second electrodes are internally formed on the first and the second substrates, respectively with the first and the second electrodes running in directions perpendicular to one another. Dielectric layers cover the first and the second electrodes. A MgO protective layer covers at least one of the dielectric layers. In one embodiment of the invention, the density of columnar crystals in the MgO protective layer is 400 columnar crystals or less per μm 2 .
In one embodiment, the MgO protective layer preferably has a refractive index of 1.45-1.74.
In another embodiment, the protective layer has (111) planes and (110) planes in a mixed manner.
According to the invention, the MgO pellets may be used to form a protective layer with a bulk density of 2.80-2.95 g/cm 3 .
In yet another embodiment, the MgO pellets preferably have a mean crystal grain size of 30-70 μm.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other advantages of the present invention will become more apparent by describing preferred embodiments thereof in detail with reference to the accompanying drawings in which:
FIG. 1 is a perspective view of an upper panel of a PDP according to an embodiment of the present invention;
FIG. 2 schematically illustrates the process of depositing a MgO layer according to an embodiment of the present invention;
FIG. 3 is a SEM photograph illustrating the crystal planes of a MgO protective layer according to an embodiment of the present invention; and
FIG. 4 is an exploded perspective view of a discharge cell of a PDP according to the prior art.
DETAILED DESCRIPTION
The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which various embodiments of the invention are shown.
FIG. 1 is a perspective view of an upper panel of a PDP according to an embodiment of the present invention.
As shown in FIG. 1 , the upper panel of a PDP according to an embodiment of the present invention is shown. A plurality of first electrodes 17 , a dielectric layer 21 and a protective layer 27 are sequentially formed on a top substrate 13 . The lower panel of the PDP is manufactured according to the prior art as set forth in FIG. 4 . For clarity of illustrating the invention, the upper panel of FIG. 1 has been flipped 180 degrees compared to the PDP of FIG. 4 . A plurality of second electrodes 115 are formed on a bottom substrate 111 facing the top substrate 13 and are positioned to run in a direction perpendicular to the first electrodes 17 . A dielectric layer 119 covers the second electrodes. Barrier ribs 123 are formed on the dielectric layer, and phosphor layers 125 are formed between the barrier ribs.
Frits are coated on the peripheries of the upper and the lower panel, which are then sealed to each other. A discharge gas such as Ne or Xe is injected between the panels, thereby completing the PDP.
With regard to the PDP according to one embodiment of the present invention, upon application of driving voltages to the electrodes, an address discharge is made between the electrodes, thereby forming a wall charge at the dielectric layer. With the discharge cells selected by the address discharge, a sustain discharge is made between a pair of electrodes formed on the upper panel by the current signals alternately fed thereto. Consequently, the discharge gas filled within the discharge space forming the discharge cells is excited and shifted, thereby generating ultraviolet rays. Phosphors are excited by the ultraviolet rays to thereby generate visible rays, and display the desired images.
As shown in FIG. 1 , in the PDP according to this embodiment of the present invention, a plurality of electrodes cross each other within the protective layer to thereby form pixels, which form a display area together surrounded by a non-display area. The plurality of electrodes 17 formed on the substrate 13 are illustrated to the left and the right of the dielectric layer 21 at their terminal portions where they are connected to a flexible printed circuit board (FPC, not shown).
With the PDP according to an embodiment of the present invention, the MgO protective layer 27 is formed by depositing MgO pellets in a MgO deposition chamber. The MgO pellets for the protective layer of the PDP according to the embodiment of the present invention are made by the following method.
First, a MgO powder with a purity of 90.0-92.0% is prepared, and a doping material is added thereto to form Mg(OH) 2 . Sufficient doping material is added to improve the purity thereof to 99.0%.
The Mg(OH) 2 has a moisture content of 50.0%, and is dried in an oven with hot air to remove the water. After drying, the Mg(OH) 2 is electrically fused in a bell type low temperature sintering furnace at 2800° C. for 60 hours, thereby calcinating it. In this way, the water of crystallization is removed from the Mg(OH) 2 to thereby obtain a MgO powder. The electrically fused MgO powder is then cooled and solidified again.
The solidified MgO powders are broken using a breaker, and are mixed with an adjunct of a solvent and an additive to form a slurry. The mixing is made using a wet mill technique, and 99.5% or more of an anhydrous solvent and Aldrich reagent are used as the additives. Zirconia balls and urethane ports are used in the wet milling.
The MgO slurry is dried by the spray drying method using an explosion proof spray dryer to form MgO granules. In the agglomeration process, MgO powder with a mean particle size of 3-5 μm is spherically agglomerated by 80 μm.
Then, the MgO granules are press-formed using a rotary press. The press-formed MgO granules are sintered and crystallized in a high temperature sintering furnace at 1700° C. When the sintering is made at that temperature, the surfaces of the MgO granules are molten and are adhered to those of other MgO granules so that the density of the MgO granules is increased and the pores thereof are reduced, thereby forming MgO pellets with a dense structure.
The bulk density of the MgO pellets is preferably from 2.80 to 2.95g/cm 3 . The bulk density of the MgO pellets is obtained through the mathematical formula 1. A sample of the MgO pellets is dried at 100° C. for 24 hours or more, and is calculated by kerosene immersion.
Bulk density (g/cm 3 )= k ×mass of dried sample (g)/(mass of moisture-contained sample (g)−mass of moisture content (g)) Formula 1
where k is 0.796 g/cm 3 , the specific gravity of kerosene.
The bulk density of MgO pellets for the protective layer of the PDP according to the embodiment of the present invention can be controlled through the steps of drying a MgO slurry mixed by the spray drying method to form MgO granules, press-forming the MgO granules, and sintering the MgO granules in a high temperature sintering furnace.
FIG. 2 schematically illustrates the process of forming a MgO protective layer using MgO pellets. The electron beam deposition method is introduced here to form the MgO protective layer on a substrate sequentially overlaid with electrodes and a dielectric layer.
In the electron beam deposition method, electron beams are accelerated by electromagnetic fields and collide against the deposition material to thereby heat and vaporize it, and form a protective layer. In this case, the energies of the electron beams are concentrated on the material surface, thereby enabling the high speed deposition and the high purity deposition. FIG. 2 illustrates an exemplary process of forming the protective layer, and the process of forming the protective layer is not limited to the electron beam deposition method.
In the process of forming the MgO protective layer 27 shown in FIG. 2 , the substrate 13 is transferred from the left to the right by rollers 51 , and loaded into an inlet port 23 of the deposition chamber 20 . After the MgO protective layer 27 is deposited on the substrate 13 , it is discharged through the outlet port 25 of the deposition chamber 20 . If there is something wrong with the substrate 13 , it is possible to unload the substrate 13 from the inlet port of the deposition chamber 23 . Since the deposition chamber 20 should be in a vacuum state, a vacuum pump (not shown) is attached thereto to exhaust the interior gas continuously. The deposition chamber 20 is isolated from the outside using shutters 33 . An electron gun 31 is operated to form the electromagnetic fields. The ions emitted from the electron gun 31 collide against the MgO pellets 57 placed at the bottom of the deposition chamber 20 to thereby deposit a MgO layer on the substrate 13 placed at the top of the deposition chamber 20 . The MgO pellets 57 have a tendency to overheat due to the ion collisions, and therefore, the MgO protective layer 27 is formed while cooling the MgO pellets 57 with a cooler 29 .
In the process of depositing a MgO protective layer 27 , if the bulk density of the MgO pellets is less than 2.80 g/cm 3 , a numbers of pores are present in the MgO pellets making it impossible to manufacture a MgO protective layer having a dense crystal structure. In contrast, if the bulk density of the MgO pellets exceeds 2.95 g/cm 3 , the MgO pellets are so densely formed that the decomposition speed of MgO is lowered, thereby deceasing the decomposition speed when forming the MgO protective layer. Although the MgO protective layer is commonly deposited at 60-110 Å/s, if the bulk density of the MgO pellets is controlled to be in the range of 2.80-2.95 g/cm 3 , its deposition speed can be increased to 130 Å/s. The relatively low bulk density can be controlled by reducing the splash phenomenon due to the thermal shock such that the substrate is not damaged during the deposition. In this case, the mean crystal grain size of the MgO pellets is preferably from 30 to 70 μm. Therefore, the MgO protective layer can be deposited onto the PDP substrate while reducing the splash phenomena.
FIG. 3 is a scanning electron microscope (SEM) photograph of a MgO protective layer according to an embodiment of the present invention. The MgO protective layer shown in FIG. 3 is formed while maintaining the partial pressure ratio of oxygen to hydrogen at about 6:1. As known from the SEM photograph of FIG. 3 , the triangle-shaped crystal planes and the rectangle-shaped crystal planes are uniformly mixed in the MgO protective layer according to the embodiment of the present invention. The triangle-shaped crystal plane is a plane (111), and the rectangle-shaped crystal plane is a plane (110). By controlling the partial pressure of oxygen and hydrogen when depositing the MgO protective layer on the substrate of the PDP, the number of columnar crystals is varied. In order to evaluate the influence of the number of columnar crystals in the MgO protective layer on the discharge quality of the PDP, several experiments were made as set forth below.
EXPERIMENTAL EXAMPLES
In order to evaluate the features of the MgO protective layer as a function of the columnar crystal density (measured as the number of columnar crystals per μm 2 ), the discharge delay times as a function of the respective numbers of columnar crystals in a 1 μm 2 area of a MgO protective layer were measured. The time required for applying the driving voltage to the PDP through scanning electrodes is referred to as the scanning time. Although the discharge occurs during the scanning time, the discharge does not instantly occur as soon as the driving voltage is applied so that the discharge is delayed. This is referred to as a discharge delay time. The discharge delay time is divided into a formation delay time and a statistical delay time. The MgO protective layer is intimately related to the discharge of secondary electrons. Therefore, in the Experimental Examples of the present invention, the discharge delay time according to the number of columnar crystals per μm 2 was measured so that the proper range for the density of columnar crystals could be derived therefrom. It is to be noted that the following Experimental Examples merely illustrate specific embodiments of the present invention, and the scope of the present invention is not limited thereto.
Experimental Example 1
MgO pellets were loaded into a MgO deposition chamber, and a MgO layer was deposited on a dielectric layer formed on a substrate. The deposited MgO protective layer had a thickness of approximately 7000 Å. The pressure inside the deposition chamber was set at 1×10 −4 Pa except during deposition when it was increased to 5.3×10 −2 Pa. The substrate was maintained at 200±5° C. while supplying oxygen at a rate of 100 sccm. Electron beams were emitted from an electron gun set at a current of 390 mA and a voltage of −15 kV DC to deposit the MgO protection layer. As a result of depositing the MgO protective layer, 200 columnar crystals per μm 2 were obtained, and the discharge delay time of the PDP with the MgO protective layer was 265 ns.
Experimental Example 2
A partial pressure ratio of oxygen to hydrogen was set at approximately 6:1 and the other conditions were maintained as set forth in Experimental Example 1. As a result of depositing the MgO protective layer, 400 columnar crystals per μm 2 were obtained, and the discharge delay time of the PDP with the MgO protective layer was 284 ns.
Experimental Example 3
A partial pressure ratio of oxygen to hydrogen was set at approximately 30:1 and the other conditions were maintained as set forth in Experimental Example 1. As a result of depositing the MgO protective layer, 1200 columnar crystals per μm 2 were obtained, and the discharge delay time of the PDP with the MgO protective layer was 322 ns.
Experimental Example 4
A partial pressure ratio of oxygen to hydrogen was set at approximately 50:1 and the other conditions were maintained as set forth in Experimental Example 1. As a result of depositing the MgO protective layer, 2100 columnar crystals per μm 2 were obtained, and the discharge delay time of the PDP with the MgO protective layer was 339 ns.
Experimental Example 5
A partial pressure ratio of oxygen to hydrogen was set at approximately 100:1 and the other conditions were maintained as set forth in Experimental Example 1. As a result of depositing the MgO protective layer, 3400 columnar crystals per μm 2 were obtained, and the discharge delay time of the PDP with the MgO protective layer was 345 ns.
Experimental Example 6
A partial pressure ratio of oxygen to hydrogen was set at approximately 150:1 and the other conditions were maintained as set forth in Experimental Example 1. As a result of the MgO protective layer, 5000 columnar crystals per μm 2 were obtained, and the discharge delay time of the PDP with the MgO protective layer was 368 ns.
The results of the Experimental Examples 1 to 6 are summarized in Table 1.
TABLE 1
Partial pressure
Number of
Experimental
ratio of oxygen to
columnar crystals
Discharge delay
Example
hydrogen
per μm 2
time
Experimental
3:1
200
265 ns
Example 1
Experimental
6:1
400
284 ns
Example 2
Experimental
30:1
1200
322 ns
Example 3
Experimental
50:1
2100
339 ns
Example 4
Experimental
100:1
3400
345 ns
Example 5
Experimental
150:1
5000
368 ns
Example 6
As shown in Table 1, for Experimental Example 2, the discharge delay time was reduced to less than 300 ns, and the discharge quality was improved. In this case, the density of columnar crystals in the MgO protective layer was about 400 columnar crystals per μm 2 or less. If the density of columnar crystals is in this range, the address discharge delay during the plasma discharge can be minimized, thereby improving the display quality.
Meanwhile, the thickness of the MgO protective layer obtained in the Experimental Examples 1 and 2 was about 6400 Å, and the refractive index thereof was 1.45-1.74. The (111) planes and the (110) planes were mixed in the MgO protective layer, and improved discharge quality was obtained.
As described above, when the density of columnar crystals of the MgO protective layer is about 400 columnar crystals per μm 2 or less, the discharge delay time is minimized, thereby improving the discharge quality of the PDP.
Furthermore, if the refractive index of the MgO protective layer is 1.45-1.74, the discharge delay time can be reduced. Also, if the (111) planes and the (110) planes are mixed in the MgO protective layer, the above effects are obtained.
Meanwhile, when the bulk density of the MgO pellets for the protective layer of the PDP is 2.80-2.95 g/cm 3 , the deposition speed of the MgO layer is increased, thereby enhancing the productivity of the PDP while reducing the splash phenomena.
If the mean crystal grain size of the MgO pellets is 30-70 μm, the productivity of the PDP is further enhanced, and the splash phenomenon is significantly reduced.
Although preferred embodiments of the present invention have been described in detail hereinabove, it should be clearly understood that many variations and/or modifications of the basic inventive concept herein taught which may appear to those skilled in the art will still fall within the spirit and scope of the present invention, as defined in the appended claims. | MgO pellets are provided for use as a protective layer for a plasma display panel providing improved physical properties. The plasma display panel includes first and second substrates facing each other. A plurality of first and second electrodes are internally formed on the first and the second substrates. Dielectric layers cover the first and the second electrodes and a MgO protective layer covers one of the dielectric layer. The MgO protective layer has 400 columnar crystals per μm 2 . | 7 |
FIELD OF THE INVENTION
The present invention relates to pharmaceutical preparations for use as tumour suppressive agents for tumours arising from prostatic adenocarcinoma, stomach cancer, breast cancer and benign prostatic hyperplasia.
BACKGROUND OF THE INVENTION
The prostate gland, which is found exclusively in male mammals, produces several components of semen and blood and several regulatory peptides. The prostate gland comprises stroma and epithelium cells, the latter group consisting of columnar secretory cells and basal nonsecretory cells. A proliferation of these basal cells as well as stroma cells gives rise to benign prostatic hyperplasia (BPH) which is one common prostate disease. Another common prostate disease is prostatic adenocarcinoma (CaP) which is the most common of the fatal pathophysiological prostate cancers and involves a malignant transformation of epithelial cells in the peripheral region of the prostate gland. Prostatic adenocarcinoma and benign prostatic hyperplasia are two common prostate diseases which have a high rate of incidence in the aging human male population. Approximately one out of every four males above the age of 55 suffers from a prostate disease of some form or another. Prostate cancer is the second most common cause of cancer related death in elderly men with there being approximately 96,000 cases diagnosed and about 26,000 deaths reported annually in the United States.
Studies of the various substances synthesized and secreted by normal, benign and cancerous prostates carried out in order to gain an understanding of the pathogenesis of the various prostate diseases reveal that certain of these substances may be used as immunohistochemical tumour markers in the diagnosis of prostate disease. The three predominant proteins or peptides secreted by a normal prostate gland are Prostatic Acid Phosphatase (PAP), Prostate Specific Antigen (PSA) and prostatic inhibin (PIP) also known as human seminal plasma inhibin (HSPI) and hereinafter referred to as HSPI.
Metabolic and immunohistochemical studies have shown that the prostate is a major source of HSPI. HSPI is involved in the feedback control of, and acts to suppress secretion of, circulating follicle stimulating hormone (FSH) both in-vitro and in-vivo in adult male rats. HSPI acts both at the pituitary as well as at the prostate site since both are provided with receptor sites for HSPI.
Both PSA and PAP have been studied as tumour markers in the detection of prostate disease but since both exhibit elevated levels in prostates having benign prostatic hyperplasia (BPM) neither marker is specific and therefore they are of limited utility.
Recently, it has been shown that HSPI concentrations in serum of patients with BPH or CaP are significantly higher than normal. The highest serum concentration of HSPI observed in normal men is approximately 40 ng/ml., while in men with either BPH or CaP serum concentrations of HSPI have been observed in the range from 300-400 ng/ml. Because there exists some overlap in the concentrations of HSPI in subjects having normal prostates and patients exhibiting either BPH or CaP, serum levels in and of themselves are of little value.
A major therapy in the treatment of prostate cancer is androgen-ablation. While most patients respond initially to this treatment, its effectiveness decreases over time possibly because of the presence of a heterogenous population of androgen-dependant and androgen-independent cells to begin with. In such a scenario, the androgen sensitive cells respond to the androgen treatment while any androgen insensitive cells present would continue to proliferate unabated.
Other forms of cancer which are currently exacting a heavy toll are breast cancer in women and cancer of the gastrointestinal tract. Currently, the use of various cancer drugs such as mitomycin, idarubicin, cisplatin, 5-flouro-uracil, methotrexate, adriamycin and donomycin form part of the therapy for treating such cancers. One drawback to such a therapeutic treatment is the presence of adverse side effects due to the drugs in the concentration ranges required for effective treatment.
Accordingly, it would be advantageous to find a more effective means of arresting the growth of prostate, breast and gastrointestinal cancer cells and tumours which can be used effectively against both androgen sensitive and androgen insensitive cells.
SUMMARY OF THE INVENTION
In one aspect the present invention provides a method of inhibiting the growth of adenocarcinoma of the prostate using human seminal prostatic inhibin (Sequence ID No. 1) wherein the human seminal prostatic inhibin is administered to the prostate in a dosage range from about 500 picograms/kg/day to about 1 milligrams/kg/day.
In another aspect of the invention there is provided a method of inhibiting the growth of adenocarcinoma of the prostate using a decapeptide (Sequence ID No. 2) wherein the decapeptide is used in a dosage range from about 250 nanograms/kg/day to about
1 milligrams/kg/day.
The present invention provides a composition for the use of inhibiting adenocarcinoma of the prostate comprising human seminal prostate inhibin (Sequence ID No. 1) present in a dosage range of about 5 nanograms/kg/day to about 10 micrograms/kg/day and an anticancer drug.
LIST OF TABLES
Table I summarizes data showing the effect of HSPI administration on the serum levels of FSH and LH (ng/ml -1 ) in intact adult male rats;
Table II summarizes data showing the effect of HSPI on cell proliferation;
Table III summarizes data showing the effect of HSPI on the weight (grams) of testes and prostate;
Table IV summarizes in-vivo data relating to HSPI dosage levels and subsequent tumour viability; and
Table V summarizes data on various hormone levels measured in rats 14 days after treatment with two different levels of HSPI.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described, reference being had to the drawings, in which:
FIG. 1 shows the complete sequence of human HSPI (Sequence ID No. 1)
FIG. 2 illustrates an HPLC profile of HSPI (sequence ID no. 1) on a gel permeation column (LKB-TSK G 3000 SW 7.5×600 mm), the material being eluted as a major peak;
FIG. 3 illustrates a reverse phase HPLC of purified HSPI (Sequence ID no. 1) on a column of Lichrosorb RP-18 (5 μm; 0.4×25 cm, eluant, A 0.1% (w/v) aqueous TFA; B, 50% CH 3 CN in 0.1% aqueous TFA; Flow rate, 1 ml/min, inset: SDS gel electrophoresis pattern of purified HSPI (method of Laemmli, 1970);
FIG. 4 displays the % survival of Dunning tumor R-3327-G cell lines on concentration of HSPI (Sequence ID No. 1);
FIG. 5 displays the % survival of Dunning tumour R-3327-G cell lines on concentration of the decapeptide analogue (Sequence ID No. 2);
FIG. 6 shows the effect of various concentrations of HSPI (Sequence ID No. 1) on the growth of R-3327-G cells;
FIG. 7 displays the patterns of DNA synthesis in R3327-G cells treated with and without HSPI, as depicted by 3 H-thymidine incorporation;;
FIG. 8 displays the effect of HSPI (Sequence ID No. 1) on tumour volume in Dunning rats;
FIG. 9 shows a comparison of tumour volume as a function of duration of treatment with saline, leuprolide and HSPI (Sequence ID No. 1);.
FIG. 10 summarizes studies of the effect of FSH on prostate cancer cell growth in-vitro and its inhibition by HSPI (Sequence ID No. 1);
FIG. 11 illustrates the R-10 peptide (Sequence ID No. 2) in the box which are the last 10 amino acids of HSPI (Sequence ID No. 1) but with lysine in position 85 replaced by tyrosine;
FIG. 12 illustrates the R-17 peptide (Sequence ID No. 3) as it appears in HSPI (Sequence ID No.1) and the R-28 peptide (Sequence ID No. 4) as it appears in HSPI.
FIG. 13 summarizes the data of Table IV in bar graph form; and
FIG. 14 illustrates the cytotoxic effect of HSPI (Sequence ID No. 1) with and without the anticancer drug idarubicin on the human gastric cancer cell line;
FIG. 15 illustrates the cytotoxic effect of HSPI (Sequence ID No. 1) with and without the anticancer drug daunomycin on the human gastric cancer cell line;
FIG. 16 illustrates the cytotoxic effect of HSPI (Sequence ID No. 1) with and without the anticancer drug adriamycin on the human gastric cancer cell line;
FIG. 17 illustrates the cytotoxic effect of HSPI (Sequence ID No. 1) with and without the anticancer drug cisplatin on the human gastric cancer cell line;
FIG. 18 illustrates the cytotoxic effect of HSPI (Sequence ID No. 1) with and without the anticancer drug methotrexate on the human gastric cancer cell line;
FIG. 19 illustrates the cytotoxic effect of HSPI (Sequence ID No. 1) with and without the anticancer drug 5-fluoro-uracil (5-FU) on the human gastric cancer cell line; and
FIG. 20 illustrates the cytotoxic effect of HSPI (Sequence ID No. 1) with and without the anticancer drug mitomycin on the human gastric cancer cell line.
DESCRIPTION OF THE INVENTION
The inventors have considered that high levels of HSPI (Sequence ID No. 1) under pathophysiological conditions associated with prostate cancer may serve as a form of defence mechanism, albeit apparently not always effective, which may be initiated by the prostate. Various in-vivo and in-vitro experimental studies have been carried out and are summarized herebelow to determine the efficacy of concentrations of HSPI (Sequence ID No. 1) higher than concentrations secreted by the diseased prostate as tumour suppressive agents for arresting or inhibiting the growth of prostatic adenocarcinoma. Studies have also been carried out to determine the efficacy of synthetic analogues of HSPI, (Sequence ID No. 1) specifically peptides having 10 amino acids (Sequence ID No. 4), 17 amino acids (Sequence ID No. 3) and 28 amino acids (Sequences ID No. 4), as tumour suppressive agents. These synthetic analogues have been shown to closely mimic the action of HSPI (Sequence ID No. 1) in suppressing circulating FSH levels preferentially without altering the levels of luteinizing hormone (LH).
The bar graph of FIG. 10 summarizes studies of the effect of FSH on prostate cancer cell growth in-vitro and its inhibition by HSPI (Sequence ID No. 1). The tumour cells were exposed for 48 hours to HSPI with 0.5% serum in tissue cultures.
PREPARATION OF HSPI
Referring to FIG. 1, HSPI (Sequence ID No. 1) is a simple nonglycosylated protein comprising at least 94 amino acid residues. HSPI produced by the prostate has a molecule weight of approximately 10.7 kDa.
HSPI (Sequence ID No. 1) antigen was purified according to the basic procedure of Thakur et al (1981) ISOLATION AND PURIFICATION OF INHIBIN FROM HUMAN SEMINAL PLASMA, Indian Journal of Experimental Biology, 19, 307-313 but with modifications (Thakur et al. and Sheth et al. (1984) CHARACTERIZATION OF A POLYPETIDE FROM HUMAN SEMINAL PLASMA WITH INHIBIN (INHIBITION OF FSH SECRETION)-LIKE ACTIVITY, FEBS Letters, 165, 11-15.). Sperm-free human seminal plasma was precipitated with alcohol (1:4 vol/vol) and then extracted with 0.05M acetate buffer, pH 4.0. The soluble proteins were separated using chromatography on a Sephadex G-100 column (3.5×100 cm) using 0.01M acetate buffer for equilibrium and elution. The fraction with FSH-suppressing activity was subjected to ion-exchange chromatography on DEAE-cellulose (3×30 cm). The column was washed initially with 0.05 Tris buffer, pH 8.0. The bound material was eluted using an NaCl gradient (0-0.5M) in the same buffer. The active material collected was subsequently purified by high pressure liquid chromatography (HPLC) using a gel permeation column (LKB-TSK G- 3000 S.W., 7.5×600 mm) and 0.01M acetate buffer, pH 4 for equilibration and elution, see FIG. 2.
The HPLC purified material exhibited a single band on SDS-Gel electrophoresis at pH 8.3 (see inset of FIG. 3). On reverse phase HPLC, the purified material eluted as a single peak, see FIG. 3.
The fractions obtained at each stage of purification were assayed for bioactivity using intact adult male rats. The assay is based on suppression of circulating FSH levels. Administration of HPLC-purified HSPI (Sequence ID No. 1) to adult male rats for 3 consecutive days caused specific suppression of circulating FSH levels, see Table 1. No significant change in LH levels was observed.
SYNTHESIS OF DECAPEPTIDE HSPI ANALOGUE
The decapeptide analogue of HSPI pep forming part of the subject invention disclosed herein is a synthetic analogue of the 85-94 amino acid residues at the carboxy terminal of the HSPI sequence. The decapeptide (Sequence ID No. 2) differs from HSPI (Sequence ID No. 1) in that the lysine residue at position 85 in HSPI (Sequence ID No. 1) is replaced by a tyrosine residue and the cysteine residue at position 87 is protected by an acetomidomethyl group. This synthetic decapeptide (Sequence ID No. 2) and other fragments were prepared using an Automated Peptide Synthesizer.
IN-VITRO AND IN-VIVO STUDIES
Studies were carried out using the rat Dunning R-3327-G tumour which is a pre-eminent animal model for the study of CaP. The Dunning tumour is a fast growing, poorly differentiated, transplantable tumour which can be maintained both in-vivo in the Copenhagen x Fisher 344 rat and in-vitro as a cell line.
EXPERIMENT 1
EFFECT OF HSPI ON IN-VITRO CELLS
Dunning tumour R-3327-G lines derived from cells dissociated in their 20th and 28th in-vivo passages in Copenhagen x 344 male carrier rats were used for the in-vitro studies. Tumours were excised and dissociated into single cells and cultured in T-25 culture flasks (Corning N.Y.). Dissociated tumour cells were dislodged from the culture flask by trypsinization (0.25% trypsin and 0.02% EDTA at 37° C. for 3 minutes) and passaged in alpha-MEM (GIBCO Labs, Grand Island, N.Y.) supplemented with 2 mM L-glutamic acid, 20% fetal bovine serum (FBS, Hyclone Labs., Logan, Vt.) and antibiotics (complete medium=CM). Cultures were passaged every five days.
For colony assay, R-3327-G cells between 2 and 10 in-vitro passages were trypsinized, dispersed into single cell suspension and cultured in 35 mm tissue culture dishes at 0.5-1.0×10 1 viable cells in 2 ml CM. Propep was diluted at various concentrations in CM, filtered, sterilized and then added at appropriate concentration to culture dishes. These culture dishes were incubated in a humidified incubator at 37° C. with 5% CO 2 for seven days. Following this the culture dishes were emptied, washed twice in cold phosphate buffer saline (PBS) solution and then fixed in absolute methanol for 5 minutes. The culture dishes were then stained with acidified Harris Hematoxylin and the colonies were counted manually.
Between about 20% to 30% of plated R-3327-G cells formed characteristic diffuse colonies within 7 days. Typically, colonies consisted of 102.3±13.7 cells. A dose dependent inhibition of both colony number and colony size were observed with addition of various concentrations of HSPI. Above concentrations of 100 ng/ml the colony inhibition was significant, leading to a 50% reduction at a HSPI (Sequence ID No. 1) concentration of 1 μg/ml. Increasing concentrations of HSPI (Sequence ID No. 1) resulted in small cell-clusters (50 cell-FIG. 4). Replenishing the culture media along with the HSPI (Sequence ID No. 1) on the 4th day of the culture resulted in more effective and consistent inhibition of colony growth than that of one time HSPI (Sequence ID No. 1) addition.
EXPERIMENT 2
EFFECT OF DECAPEPTIDE AND OTHER FRAGMENTS ON IN-VITRO CELLS
The synthetic decapeptide (Sequence ID No. 2) shown in the box in FIG. 11 has been shown to mimic the biological action of HSPI (Sequence ID No. 1) and therefore its effect on the R-3327-G cells was studied. Referring to FIG. 5, the decapeptide (Sequence ID No. 2) has a similar inhibitory action as HSPI (Sequence ID No. 1) on in-vitro R-3327-G cell culture. Specifically, a 50% colony count inhibition was observed with 50 ng/ml of the decapeptide (Sequence ID No. 2) leading to a maximum of 70% inhibition at 1 μg/ml. However, referring again to FIG. 4, an equimolar concentration of the native HSPI (Sequence ID No. 1) was found to have a greater inhibiting effect compared to the decapeptide (Sequence ID No. 2). Other peptides having 17 amino acids (Sequence ID No. 3) and 28 amino acids (Sequence ID No. 4) see FIG. 12, have demonstrated a similar efficacy for suppressing FSH levels, data not shown.
EXPERIMENT 3
EFFECT OF HSPI ON ANDROGEN DEPENDENT AND INDEPENDENT R-3327-G IN-VITRO CELL COLONIES
The R-3327-G tumours comprise both androgen sensitive and androgen insensitive cells. The effect of HSPI (Sequence ID No. 1) on these two cell populations was studied in-vitro. Cells were dissociated from a R-3327-G tumour in its 20th in-vivo passage and were cultured in the presence or absence of steriods. For comparison, cells from the 28th in-vivo passage known to be largely androgen insensitive were cultured in the same way.
The results of the effect of various concentrations of HSPI (Sequence ID No. 1) on the in-vivo cells is summarized in FIG. 6. The effect of propep was similar under all test conditions for both androgen sensitive and androgen insensitive cells. Although the actual number of colonies which appeared under each assay condition were different with these cells, the extent of propep induced colony inhibition was comparable in all.
EXPERIMENT 4
INHIBITION OF CELL-GROWTH BY HSPI
Colony inhibition might occur as a result of immediate cell death or due to delay in the cell cycle. In order to distinguish between these two routes of inhibition, the following experiment was conducted.
Aliquots of 0.5×10 1 cells were cultured in 24 well plates and incubated with various concentrations of HSPI (Sequence ID No. 1). Cell counts were taken on days 3 and 7. In control wells the number of cells increased 4-fold after 3 days and 28-fold after 7 days. At a dose of HSPI (Sequence ID No. 1) of 1 μg/ml, no increase in cell number was observed on day 3 while only a 5-fold increase was observed on day 7, see Table II.
The results of this study were further corroborated by measuring DNA synthesis using 3H-thymidine. Specifically, R-3327-G cells were cultured in 24-well tissue culture plates (Costar, Mass.) in the presence or absence of HSPI (Sequence ID No. 1) for six days. 3H-thymidine (68 Ci/mmole, ICN Ca) diluted in CM containing 10 μM thymidine (Sigma MO) was added to duplicate culture wells (0.5 μCi/ml). Plates were further incubated for 18 hrs. The amount of 3H-thymidine incorporated was estimated by precipitation with trichloro acetic acid, as described previously. FIG. 7 shows patterns of 3 H thymidine incorporation in HSPI incubated cultures on day 7, as depicted by DNA synthesis. Cultures that received HSPI (Sequence ID No. 1) in the amount of 1 μg/ml had incorporated by day 7 only about 20% of radioactivity as compared to that of the control. The inhibitory effect of the HSPI (Sequence ID No. 1) was more pronounced on day 7 than on day 3.
EXPERIMENT 5
IN-VIVO EXPERIMENT
Copenhagen x Fisher 344 F hybrid male rats were ear-tagged and implanted with R3327-G cells (1×10 1 cells/animal in the 28th in-vivo passage) as described earlier. The animals weighed approximately 500 grams at the time of tumour implantation. A treatment regimen was initiated when tumour volume measured 0.2 to 0.5 cc.
Tumour bearing animals were divided into two groups of eight. One group comprising the control group, received saline injection while the other group received HSPI (Sequence ID No. 1) dissolved in saline in the amount of 5 μg/kg subcutaneously every day.
The tumour volume was approximated by 3-dimensional measurement using the formula 0.5236×length×width×depth. The rats were sacrificed 24 days after tumour implantation as control tumours at that point in time started becoming necrotic. Accessory sex organs and tumours were excised from the rats and weighed.
Significantly reduced tumour growth was observed in animals treated with HSPI (Sequence ID No. 1) as compared to that of the saline group. Referring to FIG. 8, the difference between the tumour volume in the control group and the HSPI (Sequence ID No. 1) treated group became increasingly pronounced with longer treatment. As tumours in the control group started to become necrotic on day 24, tumour and accessory sex organs were excised and weighed on this day. Mean tumour weight of the HSPI incubated group was 2.66±0.48 g as compared to 6.44±1.19 g for the saline treated control group. A 58% reduction in tumour weight was observed at the end of the experiment i.e. on the 24 day following tumour implantation or on the 10th day following administration of HSPI (Sequence ID No. 1) as compared to the saline treated control group. No significant change was observed in testes weight and prostate weight in HSPI (Sequence ID No. 1) treated group, see Table III.
EXPERIMENT 6
IN-VIVO EXPERIMENT
The tumour bearing animals were divided into three group of 8 animals. The first group was the control group and received saline treatment. The second group received HSPI (Sequence ID No. 1) in the amount of 5 μg/kg and the third group received 1000 μg Leuprolide™/kg. This treatment regimen continued until the tumour volume for each animal reached approximately 10 cc. Tumour volumes were measured twice a week as described earlier.
The tumour volume data for each individual tumour was log transformed. Statistical analysis between treated and control group was performed by student "t" test.
As these results clearly demonstrated a growth inhibition following administration of HSPI (Sequence ID No. 1), the study was further extended to estimate tumour growth delay in Propep treated animals. Most of the tumours become necrotic by the time they reach 10 cc volume, following which the measurements may not be accurate thus, keeping this in mind, 10 cc was taken as an end point in this study. Among 8 animals in the treated group, tumour volume in 6 reached 10 cc by day 42 and in 2 by day 38. In the saline control group, tumour volume reached this size by day 30, see FIG. 9. In other words, a delay of 10 days in tumour growth was observed in the Propep treated animals. In all experiments the difference in tumour growth rate curves of treated and control groups of animals was similar.
The cells used for the foregoing experiment were from the 28th in-vivo passage, which is a poorly differentiated androgen-insensitive tumour. In order to confirm this earlier observation, one group of animals were treated with Leuprolide™ which is an anti-androgen. There was no significant difference in the tumour growth rate of in animals treated with lueprolide™ as compared to the saline control group.
EXPERIMENT 7
IN-VIVO EXPERIMENTS USING MAT-LYLU CELL LINES
The androgen independent Dunning rat adenocarcinoma cell lines, Mat-Lylu were obtained from Dr. J. T. Isaacs, Johns Hopkins Medical School, Baltimore, Md. and cultured in the laboratory by using RPMI 1640 medium containing 10% fetal calf serum and 1% antibiotics. When the cells reached confluency, they were trypsinized, dispersed into single cell suspension and the cell count was taken using hemocytometer.
Tumours were induced in adult Copenhagen male rats weighing about 200 gms by subcutaneous injection of 2×10 6 cells on two sides of the flank area. Animals were segregated into different groups and the HSPI (Sequence ID No. 1) injections were initiated on day 4 following the induction of tumour growth. Table IV shows the various concentrations HSPI (Sequence ID No. 1) injected into the animals.
Animals were injected every day and sacrificed on day 14 following the administration of tumour cells. The body weight and the tumour weights were recorded for both control and treated groups. Blood was collected through a cardiac puncture and serum FSH, LH, prolactin, testosterone and HSPI (Sequence ID No. 1) were measured by radio immunoassay. These serum levels of the above mentioned hormones are summarized in Table V for the control group and animals treated with dosages of 5 ng and 50 ng of HSPI (Sequence ID No. 1). These results show that FSH levels decrease with dosage which suggests the mechanism of action of HSPI (Sequence ID No. 1) relates to levels of FSH. In addition, testosterone levels are not adversely affected which indicates no loss of libido, in contrast to libido loss observed with current drugs used in the treatment of prostate and other forms of cancer.
A piece of tumour tissue from each animal was fixed in 10% buffered formalin to study the morphology of the cells. Table V shows the % viability of the tumours in treated groups when compared to the controls (100%). The results of table IV are summarized in the bar graph of FIG. 13.
The foregoing studies show that HSPI (Sequence ID No. 1), when administered in a predetermined concentration range, results in a significant inhibition, in-vivo of cancerous tumours associated with the prostate. Specifically, the Dunning rat studies with propep show that an effective drug dosage "window" of between about 5 ng to 500 ng per 200 grams body weight exists. These results have been corroborated by several studies.
Those skilled in the art will be aware of the methods of preparing pharmaceutically appropriate dosage forms for HSPI as applied to humans. Those skilled in the art will also appreciate that such dosages may be encapsulated and delivered using slow release technology comprising for example a liposome delivery system, polysaccharides exhibiting a slow release mechanism, salistic or other polymer implants or microspheres.
EXPERIMENT 9
STUDY OF THE EFFECT OF HUMAN SEMINAL PROSTATE INHIBIN (SEQ ID NO 1) ON FRESH GASTRIC TUMOUR CELLS IN-VITRO BY METHYL TETRAZOLIUM SALT (MTT) ASSAY
Gastric tumour specimens were collected from patients with stomach cancer undergoing gastrectomy at Tata Memorial Hospital. Tumour specimens were collected in sterile DMEM and immediately transferred to the laboratory under cold conditions. The gastric tumour specimens were finely minced with a sterile pair of scissors. The finely minced gastric tissue was incubated with 1% collagenase 1 and IV in Dulbeco's minimum essential medium (DMEM) with 10% fetal calf serum (FCS) at 37° C. with 5% CO 2 in an incubator for 1 hr. The whole mixture was then passed through a Millipore filter assembly and wire mesh (30 μm size) to get a single cell suspension of gastric tumour cells. The cells obtained were further subjected to primary culture in sterile culture bottles in 50 ml DMEM with 10% FCS and incubated for 12-18 hr. at 37° C. with 5% CO 2 in an incubator, with 10 μl of 0.1, 0.5, 1.0, and 5.0 μg/ml concentration of HSPI (Sequence ID No. 1) in a sterile 96 well microtitre plate. Blank and control in 6 microwells each were run along with tests. The plate was further incubated for 48 hrs. at 37° C. in 5% CO 2 . After 48 hrs., 10 μl of 5 mg/ml MTT was added in each well. After 6 hrs. of incubation at 37° C., 100 μl of 1N HCl:Isopropanol (1:25) was added to each well and mixed vigorously to dissolve the farmazan crystals. Absorbance values at 540 nm were determined on an ELISA reader. Blank values were subtracted from the control and test values.
The percentage cell survival for each concentration HSPI (Sequence ID No. 1) along with concentrations of known 1) anticancer drugs used in the treatment of gastric cancer including cisplatin, 5-fluoro-uracil, methotrexate, mitomycin, and 2) other anticancer drugs used in chemotherapy including idarubicin, adriamycin, doxorubicin, and daunomycin and combinations of HSPI (Sequence ID No. 1) and these anticancer drugs were calculated and compared to control. The results of these studies are summarized in FIGS. 14 to 20. As these results show, HSPI (Sequence ID No. 1) by itself acts as a cytotoxin for stomach cancer cells. However, HSPI (Sequence ID No. 1) used in combination with the various anticancer drugs gives rise to a significantly enhanced cytoxic effect on cancerous cells as illustrated in FIGS. 14-20. The symbiotic effect obtained with the various combinations is evidenced by comparison to the pure HSPI (Sequence ID No. 1) and anticancer drugs. It is anticipated that there will be an increased therapeutic effect. Specifically, as a significantly increased growth inhibitory effect is obtained with the above disclosed combinations utilizing lower concentrations of the anticancer drugs compared to the treatment regimes in which the drugs are used alone, there is the potential to provide therapy wherein adverse side effects associated with the anticancer drugs are considerably reduced than normally observed with the cancer drugs used alone in larger dosages.
The applicability of HSPI, the peptide sequences (Sequence ID Nos. 2 to 4) demonstrating an efficacy for inhibiting tumour growth and combinations of HSPI (Sequence ID No. 1) and these sequences with known anticancer drugs for the treatment of various cancers found in mammals such as prostate cancer, breast and gastrointestinal cancer will be readily apparent to those skilled in the art. Further, the use of HSPI (Sequence ID No. 1) and suitable fragments thereof for treatment of benign prostate hyperplasia will also be apparent to those skilled in the art. The studies disclosed herein are interpreted to mean that HSPI (Sequence ID No. 1), the shorter peptides (Sequence ID Nos. 2 to 4) and combinations thereof with various cancer drugs will exhibit an efficacy in the treatment of diseases characterized by elevated levels of FSH in the body.
Various amounts of HSPI (Sequence ID No.1) in the range of 10-50 μg have been administered to adult male rats for a period of 4 to 12 weeks with no adverse toxic effect on body weight, or in parameters measured by clinical chemistry.
Those skilled in the art will be aware of pharmaceutically appropriate dosage forms for the mixtures of HSPI (Sequence ID No. 1) and the anticancer as well as the manner in which a suitable dosage quantity and regimen may be derived in respect of a particular patient suffering from cancer of the gastrointestinal tract. In addition, those skilled in the art will also appreciate that such dosages may be encapsulated in time release delivery systems comprising for example a liposome delivery system, polysaccharides exhibiting a slow release mechanism, salistic or other polymer implants or microspheres.
While HSPI (Sequence ID No. 1) and the peptide analogues (Sequence ID Nos. 2 to 4) associated therewith, and combinations of HSPI and these peptide analogues with anticancer drugs has been disclosed herein as exhibiting an efficacy for the treatment of prostate cancer and cancer of the gastrointestinal tract, it will be appreciated by those skilled in the art that numerous variations exist with respect to therapeutically treating various cancers characterized by elevated FSH levels HSPI (Sequence ID No. 1) the peptide analogues (Sequence ID Nos. 2 to 4) and combinations of these compounds with various anticancer drugs without departing from the scope of the invention.
TABLE I__________________________________________________________________________EFFECT OF HSPI ADMINISTRATION ON THE SERUM LEVELSOF FSH AND LH (μG ml.sup.-1) IN INTACT ADULT MALE RATSFSH LHSaline 100 ng 1 μg 10 μg Saline 100 ng 1 μg 10 μg__________________________________________________________________________mean 349 267.4* 223.7* 132* 402.2 398 386 351±SEM±20.8 ±10.9 ±10.2 ±12.1 ±28.6 ±15.6 ±30.3 ±21.2(n = 5)% supp.-- 19.4 32.6 60.2 -- 2.4 5.1 11.5__________________________________________________________________________ *P < 0.001, in comparison with saline control. HSPI was administered (s.c.) daily for 3 days, and blood collected 2 h after the last injection
TABLE II______________________________________EFFECT OF HSPI ON CELL PROLIFERATION TREATMENT CELL COUNT 3 DAYS 7 DAYS CELLS/ INHIBI- CELLS/ INHIBI- WELL TION % WELL TION______________________________________CONTROL 2150 0 1.44 × 10.sup.4 010/μg 330 84 0.28 × 10.sup.4 805/μg 1165 45 0.708 × 10.sup.4 501/μg 2000 7 0.958 × 10.sup.4 30______________________________________ R-3327 (G) cells were seeded at a cell density 500 cells/well in 16 mm multiwell plates in MEM supplemented with 15% FBS. Different concentrations of HSPI were added as indicated. One plate was counted on day 3 while the other plate was supplemented with indicated amount of HSP and cell counts were carried out 7 days after initial addition of HSPI. Percentage inhibition was calculated taking control as 100%. Values are means of triplicate.
TABLE III______________________________________EFFECT OF HSPI ON WEIGHT OF TESTIS ANDPROSTATE WEIGHT (GRAMS) TESTIS PROSTATE______________________________________SALINE CONTROL 3.26 ± 0.19 1.26 ± 0.24HSPI TREATED 3.56 ± 0.31 1.11 ± 0.21______________________________________
TABLE IV______________________________________GROUPS % VIABILITY WHENHSPI DOSAGE COMPARED TO CONTROLS______________________________________0-CONTROL 100%5 picograms 100%50 picograms 100%0.50 nanograms 85% (mean from two expts.)5 nanograms 68%50 nanograms 63%500 nanograms 64% (mean from two expts.)5 micrograms 70%______________________________________
TABLE V__________________________________________________________________________HORMONE LEVELS IN THE RATE CIRCULATIONANIMALS TREATED DAYS 3-13. ANIMALS SACRIFICED ON DAY 14.% TUMOUR FSH PROLACTIN LH TESTO. PIPDOSE INHIBITION (NG/ML) (NG/ML) (NG/ML) (NG/ML) (NG/ML)__________________________________________________________________________CONT.0 9.35 ± .92 415 ± 194 .68 ± .24 1.4 ± .27 7.48 ± 0.55 NG 32% 4.6 ± .95 273 ± 93 .39 ± .03 2.0 ± .67 7.0 ± 1.350 NG39% 3.73 ± .36 245 ± 70 .30 ± .04 1.1 ± .98 9.39 ± 1.0PIP__________________________________________________________________________
__________________________________________________________________________SEQUENCE LISTING(1) GENERAL INFORMATION:(iii) NUMBER OF SEQUENCES: 4(2) INFORMATION FOR SEQ ID NO:1:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 94 amino acids(B) TYPE: amino acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(iii) HYPOTHETICAL: NO(xi) SEQUENCE DESCRIPTION: SEQ ID NO:1:SerCysTyrPheIleProAsnGluGlyValProGlyAspSerThr151015ArgLysCysMetAspLeuLysGlyAsnLysHisProIleAsnSe r202530GluTrpGlnThrAspAsnCysGluThrCysThrCysTyrGluThr354045GluIleSerCysCysThrLeuValSerThrProValGlyTyrAsp505560LysAspAsnCysGlnArgIlePheLysLysGluAspCysLysTyr 657075IleValValGluLysLysAspProLysLysThrCysSerValSer808590 GluTrpIleIle(2) INFORMATION FOR SEQ ID NO:2:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 10 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: peptide(iii) HYPOTHETICAL: NO(xi) SEQUENCE DESCRIPTION: SEQ ID NO:2:TyrThrCysSerValSerGluTrpGlyIle1 510(2) INFORMATION FOR SEQ ID NO:3:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 17 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: peptide(iii) HYPOTHETICAL: NO(xi) SEQUENCE DESCRIPTION: SEQ ID NO:3:SerCysTyrPheIleProAsnGluGl yValProGlyAspSerThr151015ArgLys(2) INFORMATION FOR SEQ ID NO:4:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 28 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: peptide(iii) HYPOTHETICAL: NO(xi) SEQUENCE DESCRIPTION: SEQ ID NO:4:IlePheLysLysGluAspCysLysTyrIleValValGluLysLys151015AspProLysLysThrCysSerVal SerGluTrpGlyIle2025 | The present invention provides pharmaceutical preparations for inhibiting in-vitro and in-vivo cancerous prostate, gastrointestinal and breast tumors. In one embodiment the pharmaceutical preparation includes human seminal prostatic inhibin which may be administered in an appropriate dosage form, dosage quantity and dosage regimen to a patient suffering from prostate cancer. In another embodiment the pharmaceutical preparation includes a mixture of human seminal prostatic inhibin and a anticancer drug which may be administered in an appropriate dosage form, dosage quantity and dosage regimen to a patient suffering from, for example gastrointestinal cancer. The anticancer drug of the latter mixture may be one selected from the group of drugs including mitomycin, idalubicin, cisplatin, 5-fluorouracil, methotrexate, adriamycin and daunomycin. | 0 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to copending U.S. provisional application entitled, “Ink Compositions Including Unattached Polymeric Binders,” having Ser. No. 60/621,501, filed Oct. 22, 2004, which is entirely incorporated herein by reference.
BACKGROUND
[0002] The use of inkjet printing systems in offices and homes has grown dramatically in recent years. The growth can be attributed to drastic reductions in cost of inkjet printers and substantial improvements in print resolution and overall print quality. While the print quality has drastically improved, research and development efforts continue toward improving the permanence of inkjet images because this property still falls short of the permanence produced by other printing and photographic techniques. A continued demand in inkjet printing has resulted in the need to produce images of high quality, high permanence, and high durability, while maintaining a reasonable cost.
[0003] In inkjet printing, the inkjet image is formed on a print medium when a precise pattern of dots is ejected from a drop-generating device known as a printhead. The typical inkjet printhead has an array of precisely formed nozzles located on a nozzle plate and attached to an inkjet printhead array. The nozzles are typically 30 to 40 micrometers in diameter. The inkjet printhead array incorporates an array of firing chambers that receive liquid ink, which includes pigment-based inks and/or dye-based inks dissolved or dispersed in a liquid vehicle, through fluid communication with one or more ink reservoirs. Each chamber has a thin-film resistor, known as a firing resistor, located opposite the nozzle so ink can collect between the firing resistor and the nozzle. Upon energizing of a particular firing resistor, a droplet of ink is expelled through the nozzle toward the print medium to produce the image. The printhead is held and protected by an outer packaging referred to as a print cartridge or an inkjet pen.
[0004] However, there is still a need for pigment-based ink having stability, low viscosity, and compatibility with multiple solvents and paper types, as well as being able to produce images of high gloss, uniform area fill, and good black/color mixing, while maintaining a reasonable cost.
SUMMARY
[0005] Briefly described, embodiments of this disclosure include ink formulations. One exemplary ink formulation, among others, includes an aqueous vehicle; a pigment dispersed throughout the aqueous vehicle, the pigment having polymeric binders attached thereto; and at least one unattached polymeric binder dispersed throughout the aqueous vehicle; wherein the polymeric binders attached to the pigment are chemically similar to the at least one unattached polymeric binder.
[0006] One exemplary ink composition, among others, includes a pigment A represented by the formula in FIG. 3 , wherein a ratio of n to m is about 1.1 to about 4:1, wherein o and p can each be about 5 to 100% of the value of m, wherein PEG is polyethylene glycol and PPG is polypropylene glycol, and wherein is a pigment. Another exemplary ink composition, among others, includes a pigment B represented by the formula in FIG. 4 , wherein R1 can be selected from the following: H and methyl, wherein R2 can be selected from the following: an alkyl group, wherein the value of x, y1, and y2 correspond to an acid number that is from about 3 to 500, wherein the value of x, y1, and y2 correspond to a glass transition temperature of about −30 to 120° C., wherein the value of k is about 0 to 100%, wherein the value of z is about 5 to 80% of the value of y1, wherein PEG is polyethylene glycol and PPG is polypropylene glycol, and wherein is a pigment.
[0007] Another exemplary ink composition, among others, includes a pigment C represented by the formula in FIG. 5 , wherein the value of a, b, and c correspond to an acid number that is about 3 to 500, wherein the value of a, b, and c correspond to a glass transition temperature of about −30 to 120° C., wherein PEG is polyethylene glycol and PPG is polypropylene glycol, and wherein is a pigment.
[0008] Another exemplary ink composition, among others, includes a pigment D represented by the formula in FIG. 6 , wherein the ratio of e to f is about 1:1,
[0009] wherein the value of g is about 5 to 100% of the value of f, wherein the value of h is about 1 to 10, wherein PEG is polyethylene glycol and PPG is polypropylene glycol, and wherein is a pigment.
[0010] Another exemplary ink composition, among others, includes a pigment E represented by the formula in FIG. 7 , wherein the value of q is about 1 to 100, wherein the value of r is about 1 to 100 monomer units per chain, wherein the value of s is about 1 to 100 monomer units per chain, wherein the value of t is about 1 to 100 monomer units per chain, and wherein is a pigment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Many aspects of this disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale.
[0012] FIG. 1 is a schematic view of an embodiment of the ink composition of the present disclosure.
[0013] FIG. 2 is a schematic view of an embodiment of the ink composition disposed on a substrate.
[0014] FIG. 3 illustrates an embodiment of a representative reaction mechanism to produce a modified pigment A.
[0015] FIG. 4 illustrates another embodiment of a representative reaction mechanism to produce a modified pigment B.
[0016] FIG. 5 illustrates another embodiment of a representative reaction mechanism to produce a modified pigment C.
[0017] FIG. 6 illustrates another embodiment of a representative reaction mechanism to produce a modified pigment D.
[0018] FIG. 7 illustrates another embodiment of a representative reaction mechanism to produce a modified pigment E.
[0019] FIG. 8 is an illustrative graph illustrating a comparison of a standard chemically modified yellow pigment and a representative embodiment of modified pigment A.
DETAILED DESCRIPTION
[0020] It has been fortuitously and unexpectedly discovered that novel ink compositions according to embodiments of the present disclosure advantageously exhibit desirable rheological properties. In addition, modified pigments, formulations, and methods of making modified pigments and formulations, are described. Exemplary embodiments of the disclosed modified pigments, when used in ink formulations, produce images of high gloss, uniform area fill, and/or good black/color mixing. Embodiments of the disclosed modified pigments have high stability, low viscosity, and compatibility with multiple solvent and paper types, as compared to other pigments.
Part A
[0021] As shown in FIG. 1 , embodiments of the ink composition 10 include both polymeric binders B attached to a pigment P and unattached/free polymeric binders F dispersed throughout a vehicle 16 . It is contemplated that the viscosity of the ink composition 10 may be lowered when the attached polymeric binders B and free polymeric binders F are chemically similar. Without being bound to any theory, it is believed that this reduction in viscosity may be due in part to the addition of the chemically similar free polymeric binders F, which may substantially reduce electrostatic and/or electrosteric interactions between the attached binders B and the vehicle 16 .
[0022] It is to be understood that the vehicle 16 is an aqueous vehicle in embodiments of the present disclosure. As used herein, “aqueous vehicle” refers to the vehicle 16 in which pigment/colorant P is placed to form an ink composition 10 . Ink vehicles are known in the art, and a wide variety of ink vehicles may be used with embodiments of the compositions, systems and methods of the present disclosure. Such aqueous vehicles 16 may include solvents, including but not limited to glycols, amides, pyrrolidones, and/or the like, and/or mixtures thereof in amounts ranging between about 0.01 and 20 wt %; alternately, between about 0.01 and 7 wt %; or between about 0.01 and 4 wt %. Aqueous vehicles 16 may also optionally include one or more water-soluble surfactants/amphiphiles in amounts ranging between about 0 and 5 wt %; alternately, between about 0.1 and 2 wt %. The balance of the aqueous vehicle 16 is generally water in embodiments of the present disclosure.
[0023] In embodiments of the ink composition 10 , one or more co-solvents may be added to the aqueous vehicle 16 in the formulation of the ink composition 10 . Examples of suitable classes of co-solvents include, but are not limited to, aliphatic alcohols, aromatic alcohols, diols, caprolactams, lactones, formamides, acetamides, long chain alcohols, and mixtures thereof. Examples of suitable co-solvent compounds include, but are not limited to, primary aliphatic alcohols of 30 carbons or fewer, primary aromatic alcohols of 30 carbons or fewer, secondary aliphatic alcohols of 30 carbons or fewer, secondary aromatic alcohols of 30 carbons or fewer, 1,2-alcohols of 30 carbons or fewer, 1,3-alcohols of 30 carbons or fewer, 1,5-alcohols of 30 carbons or fewer, N-alkyl caprolactams, unsubstituted caprolactams, substituted formamides, unsubstituted formamides, substituted acetamides, unsubstituted acetamides, and mixtures thereof.
[0024] Some specific suitable examples of co-solvents include, but are not limited to 1,5-pentanediol, 2-pyrrolidone, 1,2-hexanediol, 2-ethyl-2-hydroxymethyl-1,3-propanediol, diethylene glycol, 3-methoxybutanol, 1,3-dimethyl-2-imidazolidinone, and mixtures thereof. The co-solvent concentration may range between about 0.01 wt. % and 50 wt. %. In an embodiment, the co-solvent concentration ranges between about 0.1 wt. % and 20 wt. %.
[0025] In embodiments of the ink composition 10 of the present disclosure wherein water-soluble surfactants are added to the aqueous vehicle, it is to be understood that these surfactants may be added as free components to the ink composition 10 and are not otherwise associated or intended to become part of the polymeric binders B/unattached binders F described herein. Non-limitative examples of suitable surfactants include fluorosurfactants, non-ionic surfactants, amphoteric surfactants, ionic surfactants, and/or mixtures thereof.
[0026] Examples of suitable surfactants include, but are not limited to the following commercially available tradenames: ZONYLs (fluorosurfactants), available from E.I. du Pont de Nemours and Co. located in Wilmington, Del. and TERGITOLs (alkyl polyethylene oxides), available from Union Carbide in Piscataway, N.J.
[0027] Examples of amphiphiles/surfactants that may be used in embodiments of the present disclosure include, but are not limited to iso-hexadecyl ethylene oxide 20 and amine oxides, such as N,N-dimethyl-N-dodecyl amine oxide, N,N-dimethyl-N-tetradecyl amine oxide, N,N-dimethyl-N-hexadecyl amine oxide, N,N-dimethyl-N-octadecyl amine oxide, N,N-dimethyl-N-(Z-9-octadec-enyl)—N-amine oxide, and mixtures thereof. The concentration of the amphiphiles/surfactants may range between about 0 wt. % and 5 wt. %. In an embodiment, the concentration of amphiphiles/surfactants ranges between about 0.1 wt. % and 2 wt. %.
[0028] It is to be understood that various types of additives may be employed in the ink composition 10 according to embodiments of the present disclosure to optimize the properties of the ink composition 10 for specific applications. For example, biocides may be used in an embodiment of the ink composition 10 to inhibit growth of microorganisms. One suitable non-limitative example of a biocide is commercially available under the tradename PROXEL GXL (a solution of 1,2-benzisothiazolin-3-one (BIT), sodium hydroxide, and dipropylene glycol) from Avecia Inc. located in Wilmington, Del. Sequestering agents such as EDTA may be included to substantially eliminate potential deleterious effects of heavy metal impurities (if any). Buffer solutions may be used to control the pH of the ink composition 10 , as desired and/or necessitated by a particular end use.
[0029] The ink composition 10 according to embodiments of the present disclosure includes pigment P dispersed throughout the aqueous vehicle 16 . It is to be understood that any suitable pigment P that is capable of having polymeric binders B attached thereto may be used. Some non-limitative examples of suitable pigments include those supplied by Cabot Corp. in Billerica, Mass. Non-limitative examples of some suitable polymer B attached pigments P are described in U.S. Pat. No. 6,432,194 assigned to Cabot Corporation and issued to Johnson et al. entitled “Method of attaching a group to a pigment,” which patent is incorporated herein in its entirety.
[0030] The pigment P may have any suitable polymeric binders B attached thereto. The attached polymeric binders B may be selected using a variety of parameters including, but not limited to molecular weight, acid number and/or the type of monomers within the polymeric binders B. In one embodiment, the molecular weight of the attached polymeric binders B ranges between about 4,000 and about 20,000. In another embodiment, the acid number of the attached polymeric binders B may range between about 50 and about 300. Examples of suitable monomers within the polymeric binders B include, but are not limited to styrene, acrylic acid, substituted acrylic acids, maleic anhydride, and/or substituted maleic anhydrides. In addition, the pigment P can include pigments such as those described in more detail in PART B.
[0031] Some non-limitative examples of polymeric binders B capable of attaching to the pigment P are polyurethane resins, styrene-acrylic resins/polymers/copolymers, styrene-maleic anhydride resins/polymers/copolymers, styrene-acrylic resins/polymers/copolymers having ethylene and/or propylene glycol graphed thereto, styrene-maleic anhydride resins/polymers/copolymers having ethylene and/or propylene glycol graphed thereto, and combinations thereof. Styrene-acrylic resins/polymers/copolymers having ethylene and/or propylene glycol graphed thereto and styrene-maleic anhydride resins/polymers/copolymers having ethylene and/or propylene glycol graphed thereto, are discussed in more detail in PART B (e.g., FIGS. 1 and 2 ).
[0032] Some suitable polyurethane resins are commercially available from Avecia in Manchester, England. Some suitable styrene-acrylic resins/polymers are commercially available under the tradenames JONCRYL 586 (J586), JONCRYL 671 (J671) and JONCRYL 696 (J696) from Johnson Polymer, Inc. located in Sturtevant, Wis., and SMA (Styrene Maleic Anhydride) polymers available from Sartomer located in Exton, Pa.
[0033] In an embodiment, the pigment P having polymeric binders B attached thereto is present in an amount ranging between about 1 wt. % and 10 wt. % of the ink composition and about 0.5 to 2 wt. % of the ink composition. In an alternate embodiment, the pigment P having polymeric binders B attached thereto is present in an amount ranging between about 3 wt. % and 5 wt. % of the ink composition 10 .
[0034] An embodiment of the ink composition 10 further includes at least one unattached/free polymeric binder F dispersed throughout the aqueous vehicle 16 . It is to be understood that the unattached polymeric binders F may be substantially homogeneously and/or non-homogeneously mixed throughout the aqueous vehicle 16 . In an embodiment, the unattached polymeric binders F are present in an amount ranging between about 0.1 wt. % and 6 wt. % of the ink composition. In an alternate embodiment, the unattached polymeric binders F are present in an amount ranging between about 1 wt. % and 3 wt. % of the ink composition 10 .
[0035] In an embodiment of the ink composition 10 of the present disclosure, selected unattached polymeric binders F are formed from a polymeric material that is chemically similar to the selected attached polymeric binders B. “Chemically similar” as defined herein denotes compounds that have the same or similar molecular weight, acid number and/or monomer composition. It is to be understood that “similar” in regard to molecular weights as defined herein is contemplated to encompass compounds having molecular weights ranging between about 4000 and 18000.
[0036] Similar to the attached polymeric binders B, in an embodiment of the ink composition 10 , the molecular weight of the unattached polymeric binders F ranges between about 4,000 and 20,000, and the acid number ranges between about 50 and 300. Non-limitative examples of suitable unattached polymeric binders F include the polyurethane resins and styrene-acrylic resins/polymers as previously described in reference to the attached polymeric binders B.
[0037] It is believed, without being bound to any theory, that when the unattached polymeric binders F and the attached polymeric binders B are chemically similar, the electrostatic and/or electrosteric interactions between the attached polymeric binders B and the aqueous vehicle 16 may be substantially reduced. This reduction may advantageously help to lower the viscosity of the ink composition 10 . The viscosity of the ink composition 10 of the present disclosure ranges between about 2 cps and 10 cps. In an alternate embodiment, the viscosity of the ink composition 10 of the present disclosure ranges between about 2 cps and 6 cps. The reduced viscosity of the ink composition 10 may advantageously help to improve ink reliability, ink durability, and print quality.
[0038] FIG. 2 illustrates an embodiment of the ink composition 10 deposited on a substrate 14 to form a pigmented ink system 12 . It is to be understood that the ink composition 10 may be deposited on the substrate 14 using any suitable printing technique, such as an ink jet printer. Examples of suitable substrate 14 materials include, but are not limited to cellulosic materials (e.g., paper materials), wood, textile materials, polymeric materials, metals and/or mixtures thereof.
[0039] In a method of making an embodiment of the ink composition 10 , an amount of the pigment P having polymeric binders B attached thereto is admixed in a selected aqueous vehicle 16 to form an ink fluid. Further, at least one unattached polymeric binder F may be admixed with the ink fluid to form the ink composition 10 . It is to be understood that the materials described above may be selected and that the attached polymeric binders B are substantially chemically similar to the unattached polymeric binders F.
[0040] To further illustrate the present disclosure, the following examples are given. It is to be understood that these examples are provided for illustrative purposes and are not to be construed as limiting the scope of the present disclosure.
Part A Examples
[0041] Table 1 of PART A illustrates various examples of the ink composition 10 according to embodiments of the present disclosure. The examples labeled A-J, list the ingredients used, the viscosity of the embodiment of the ink composition 10 .
[0000]
TABLE 1
Examples A-J
Ingredients - all
wt %
A
B
C
D
E
F
G
H
I
J
Cabot Pigment
4
4
0
0
0
0
0
0
0
0
J586 attached
Cabot Pigment
0
0
4
4
0
0
4
4
0
0
J671 attached
Cabot Pigment
0
0
0
0
4
4
0
0
4
4
J696 attached
Joncryl 586,
0
2
0
0
0
0
2.5
0
2.5
0
AN 108, Mw 4600
Joncryl 671,
0
0
0
2
0
0
0
0
0
0
AN 214, Mw 17250
Joncryl 696, AN
0
0
0
0
0
2
0
0
0
0
220, Mw 16000
Fluorosurfactant
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
2-Pyrrolidone
7
7
7
7
7
7
7
7
7
7
1,2 Alkanediol
4
4
4
4
4
4
4
4
4
4
Proxel GXL
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
Water*
Bal
Bal
Bal
Bal
Bal
Bal
Bal
Bal
Bal
Bal
Viscosity
2.09
2.44
10.45
6.3
13.12
6.68
6.74
7.31
9.84
10.53
*Water makes up the balance (Bal) of the vehicle
[0042] Comparing ink compositions C and D illustrates how the addition of unattached binders B may reduce the viscosity of the final ink composition 10 . Example C contains CABOT PIGMENT with JONCRYL 671 attached thereto and no unattached binders in the aqueous vehicle 16 . The viscosity of ink composition C was 10.45 cps. Example D contains the same composition as Example C with the addition of 2 wt. % unattached JONCRYL 671. The viscosity of Example D was lowered to 6.3 cps, making the ink composition 10 more desirable for printing.
[0043] Without being bound to any theory, it is believed that the slight rise in viscosity between ink composition A and ink composition B may be due to the following. In this case, both the attached polymeric binder B and free polymeric binder F have low molecular weights, and the pigment P-binder B interactions are less than the vehicle 16 -binder B interactions. Therefore, the ink viscosity increases slightly because of the vehicle 16 -binder B interaction. In other examples, the molecular weights of the polymers are higher; thus there is more pigment P-vehicle 16 interaction.
[0044] The ink compositions 10 according to embodiments of the present disclosure may offer many advantages, examples of which include, but are not limited to the following. The combination of the chemically similar attached polymeric binders B and unattached polymeric binders F may advantageously lower the viscosity of the ink composition 10 . The lower viscosity may result in improved pen reliability, ink durability, and/or high print quality. Still further, the addition of unattached polymeric binders F that are chemically similar to the attached polymeric binders B may advantageously reduce the electrostatic and/or electrosteric interactions between the attached polymeric binders B and the aqueous vehicle 16 .
Part B
[0045] In general, the modified pigment in FIG. 3 includes, but is not limited to, a styrene-maleic anhydride co-polymer having a polyethylene glycol (PEG) and/or polypropylene glycol (PPG) compound grafted thereon. The styrene-maleic anhydride co-polymer is attached covalently to a sulfatoethylsulfone-pigment via an amine-thio linkage (hereinafter “modified pigment A”). Typically, the PEG/PPG and the sulfatoethylsulfone-pigment are disposed on different monomers of maleic anhydride. The modified pigment A is substantially resistant to chemical attacks from acids, bases, and salts. In addition, the modified pigment A is miscible with various co-solvents due, at least in part, to the ethylene glycol and/or propylene glycol.
[0046] FIG. 3 illustrates an embodiment of a representative reaction mechanism to produce the modified pigment A. A styrene-maleic anhydride co-polymer is provided and then reacted with AET-HCl (AET=NH 2 CH 2 CH 2 SH), and an amine terminated PEG and/or PPG with a base (e.g., triethylamine), where the components are in a solvent such as, but not limited to, dimethyl sulfide (DMS). Under typical reaction conditions, the pH is basic (e.g., above 10.5). The product of the reaction is the styrene-maleic anhydride co-polymer having an amine-thio linkage on a maleic anhydride monomer and an amine terminated PEG and/or PPG on a different maleic anhydride monomer. The monomers can be randomly arranged or block arranged.
[0047] The percentage of amine terminated PEG and PPG grafted onto the styrene-maleic anhydride co-polymer backbone can range from about 0.01 to 90%, about 0.01 to 50%, or from about 5 to 20% based on the anhydride groups.
[0048] Next, the product is reacted with NaOH, a sulfatoethylsulfone-pigment, and sodium acrylate to produce modified pigment A. Under typical reaction conditions, the pH is basic (e.g., above a pH of 10.5). The amount of the styrene-maleic anhydride co-polymer covalently bonded to the surface area of the sulfatoethylsulfone-pigment can range from about 0.01 to 50%, about 0.01 to 20%, or from about 5 to 15%.
[0049] The ratio of n to m can be about 1.1, about 2:1, about 3:1, and about 4:1. The value of o and p can each be from about 5 to 100%, about 5 to 50%, or about 5 to 10% of the value of m.
[0050] The molecular weight of the styrene-maleic anhydride co-polymer having PEG and/or PPG (e.g., PEG, PPG, and combinations thereof (e.g., co-polymers thereof)) grafted thereon can range from about 1000 to 100,000, about 1000 to 30,000, or about 1000 to 10,000.
[0051] The molecular weight of PEG can range from about 300 to 10,000 MW, about 300 to 5,000 MW, about 500 to 2,000 MW. The molecular weight of PPG can range from about 300 to 5,000 MW, about 300 to 2,000 MW, or about 300 to 1,000 MW. The molecular weight of the co-polymer of polyethylene glycol and polypropylene glycol can range from between about 300 to 10,000 MW, 300 to 5,000 MW, or from 300 to 2,000 MW.
[0052] In general, the modified pigment in FIG. 4 includes, but is not limited to, a styrene-acrylate co-polymer having a PEG and/or PPG grafted thereon, attached covalently to a sulfatoethylsulfone-pigment via an amine-thio linkage (hereinafter “modified pigment B”). Typically, the PEG/PPG and the sulfatoethylsulfone-pigment are associated with different monomers of the acrylic monomer. The modified pigment B is substantially resistant to chemical attacks from acids, bases, and salts. In addition, the modified pigment B is miscible with various co-solvents due, at least in part, to the ethylene glycol and/or propylene glycol.
[0053] FIG. 4 illustrates an embodiment of a representative reaction mechanism to produce the modified pigment B. A styrene-acrylic co-polymer is provided and then reacted with NH 2 CH 2 CH 2 SH, HCl, and an amine terminated PEG and/or PPG. Under typical reaction conditions, pH is basic (e.g., above a pH of 10.5). R1 can be H or methyl. R2 can include an alkyl group. In particular, R2 can be H, methyl, ethyl, propyl, and butyl. The monomers can be randomly arranged or block arranged. The product of the reaction is the styrene-acrylic co-polymer having an amine-thio linkage on an acrylic monomer and an amine terminated PEG and/or PPG on a different acrylic monomer.
[0054] The percentage of amine terminated PEG and PPG grafted onto the styrene-acrylic co-polymer backbone can range from about 1 to 90%, about 1 to 50%, and from about 5 to 20% based on the reactive carboxylic acid groups.
[0055] Next, the product is reacted with NaOH, a sulfatoethylsulfone-pigment, and sodium acrylate to produce modified pigment B. Under typical reaction conditions, pH is basic (e.g., above pH of 10.5). The amount of the styrene-acrylic co-polymer covalently bonded to the surface area of the sulfatoethylsulfone-pigment can range from about 0.01 to 50%, about 0.01 to 20%, and from about 5 to 15%.
[0056] The value of x, y1, and y2 in modified pigment B correspond to an acid number that is from about 3 to 500, about 3 to 400, about 3 to 300, about 3 to 250, about 3 to 200, about 10 to 500, about 10 to 400, about 10 to 300, about 10 to 250, about 10 to 200, about 25 to 500, about 25 to 400, about 25 to 300, about 25 to 250, about 25 to 200, about 50 to 500, about 50 to 400, about 50 to 300, about 50 to 250, and about 50 to 200. In addition, the value of x, y1, and y2 in modified pigment B correspond to a glass transition temperature of about −30 to 120° C., about −30 to 110° C., about −30 to 80° C., about −20 to 120° C., about −20 to 110° C., about −20 to 80° C., about −10 to 120° C., about −10 to 110° C., about −10 to 80° C., about 0 to 120° C., about 0 to 110° C., about 0 to 80° C., about 10 to 120° C., about 10 to 110° C., about 10 to 80° C., about 20 to 120° C., about 20 to 110° C., and about 20 to 80° C. The value of k in modified pigment B can be from about 0 to 100%, about 5 to 75%, about 5 to 50%, about 5 to 25%, or about 5 to 10% of the value of y1. The value of z in modified pigment B can be from about 5 to 80%, about 5 to 65%, about 5 to 50%, about 10 to 50%, and about 10 to 30% of the value of y1.
[0057] The molecular weight of the styrene-acrylic co-polymer having PEG and/or PPG grafted thereon can range from about 1000 to 1000,000, about 1,000 to 20,000, about 2,000 to 15,000.
[0058] The molecular weight of PEG can range from about 300 to 10,000 MW, about 300 to 5,000 MW, about 500 to 2,000 MW. The molecular weight of PPG can range from about 300 to 5,000 MW, about 300 to 2,000 MW, about 300 to 1,000 MW. The molecular weight of the co-polymer of polyethylene glycol and polypropylene glycol can range from between about 300 to 10,000 MW, 300 to 5,000 MW, and from 300 to 2,000 MW.
[0059] In general, the modified pigment in FIG. 5 includes, but is not limited to, a styrene-acrylic co-polymer having a PEG and/or PPG grafted thereon, attached covalently to a sulfatoethylsulfone-pigment via an amine linkage (hereinafter “modified pigment C”). Typically, the PEG/PPG and the sulfatoethylsulfone-pigment are disposed on different monomers of acrylic monomer. The modified pigment C is substantially resistant to chemical attacks from acids, bases, and salts. In addition, the modified pigment C is miscible with various co-solvents due, at least in part, to the ethylene glycol and/or propylene glycol.
[0060] FIG. 5 illustrates an embodiment of a representative reaction mechanism to produce the modified pigment C. The sulfatoethylamine-pigment is provided and reacted with a polyamine (e.g., primary amine, secondary amine, and polyethyleneimine (PEI)) to produce an amine terminated sulfatoethylsulfone-pigment. The amine terminated sulfatoethylamine-pigment is reacted with a styrene-acrylic co-polymer having the PEG and/or the PPG grafted thereto to produce modified pigment C. The PEG/PPG and the sulfatoethylamine-pigment are disposed on different monomers of the acrylic monomer. The monomers can be randomly arranged or block arranged.
[0061] The styrene-acrylic co-polymer having the PEG and/or the PPG grafted thereto can be fabricated in a similar manner as described above in reference to FIGS. 3 and 4 and the accompanying text. The percentage of amine terminated PEG and PPG grafted onto the styrene-acrylic co-polymer backbone can range from about 0.01 to 90%, about 0.01 to 50%, and from about 5 to 20% based on the anhydride groups.
[0062] The amount of the styrene-acrylic co-polymer covalently bonded to the surface area of the amine terminated sulfatoethylamine-pigment can range from about 0.01 to 50%, about 0.01 to 20%, and from about 5 to 15%.
[0063] The value of a, b, and c in modified pigment C correspond to an acid number that is from about 3 to 500, about 3 to 400, about 3 to 300, about 3 to 250, about 3 to 200, about 10 to 500, about 10 to 400, about 10 to 300, about 10 to 250, about 10 to 200, about 25 to 500, about 25 to 400, about 25 to 300, about 25 to 250, about 25 to 200, about 50 to 500, about 50 to 400, about 50 to 300, about 50 to 250, and about 50 to 200. In addition, the value of a, b, and c in modified pigment C correspond to a glass transition temperature of about −30 to 120° C., about −30 to 110° C., about −30 to 80° C., about −20 to 120° C., about −20 to 110° C., about −20 to 80° C., about −10 to 120° C., about −10 to 110° C., about −10 to 80° C., about 0 to 120° C., about 0 to 110° C., about 0 to 80° C., about 10 to 120° C., about 10 to 110° C., about 10 to 80° C., about 20 to 120° C., about 20 to 110° C., and about 20 to 80° C.
[0064] The molecular weight of the styrene-acrylic co-polymer having PEG and/or PPG grafted thereon can range from about 1000 to 100,000, about 1,000 to 20,000, about 2,000 to 15,000.
[0065] The molecular weight of PEG can range from about 300 to 10,000 MW, about 300 to 5,000 MW, about 500 to 2,000 MW. The molecular weight of PPG can range from about 300 to 5,000 MW, about 300 to 2,000 MW, about 300 to 1,000 MW. The molecular weight of the co-polymer of polyethylene glycol and polypropylene glycol can range from between about 300 to 10,000 MW, 300 to 5,000 MW, and from 300 to 2,000 MW.
[0066] In general, the modified pigment in FIG. 6 includes, but is not limited to, a styrene-maleic anhydride co-polymer having a PEG and/or PPG grafted thereon, attached covalently to a sulfatoethylamine-pigment via an amine linkage (hereinafter “modified pigment D”). Typically, the PEG/PPG and the sulfatoethylamine-pigment are disposed on different monomers of maleic anhydride monomer. The modified pigment D is substantially resistant to chemical attacks from acids, bases, and salts. In addition, the modified pigment D is miscible with various co-solvents due, at least in part, to the ethylene glycol and/or propylene glycol.
[0067] FIG. 6 illustrates an embodiment of a representative reaction mechanism to produce the modified pigment D. The sulfatoethylamine-pigment is provided and reacted with polyamine (e.g., primary amine, secondary amine, and polyethyleneimine (PEI)) to produce an amine terminated sulfatoethylsulfone-pigment. The amine terminated sulfatoethylamine-pigment is reacted with a styrene-maleic anhydride co-polymer having the PEG and/or the PPG grafted thereto to produce modified pigment D. The PEG/PPG and the sulfatoethylamine-pigment are disposed on different monomers of the maleic anhydride monomer. The monomers can be randomly arranged or block arranged.
[0068] The styrene-maleic anhydride co-polymer having the PEG and/or the PPG grafted thereto can be fabricated by reacting structure P with an amine terminated PEG and/or PPG. The percentage of amine terminated PEG and PPG grafted onto the styrene-maleic anhydride co-polymer backbone can range from about 0.01 to 90%, about 0.01 to 50%, and from about 5 to 20% based on the anhydride groups.
[0069] The amount of the styrene-maleic anhydride co-polymer covalently bonded to the surface area of the amine terminated sulfatoethylamine-pigment can range from about 0.01 to 50%, about 0.01 to 20%, and from about 5 to 15%.
[0070] The ratio of e to f can be about 1:1, about 2:1, about 3:1, and about 4:1. The value of g is about 5 to 100%, about 5 to 75%, about 5 to 50%, or about 5 to 20% of the value of f. The value of h is about 1 to 10.
[0071] The molecular weight of the styrene-maleic anhydride co-polymer having PEG and/or PPG grafted thereon can range from about 1000 to 100,000, about 1000 to 30,000, about 1000 to 10,000.
[0072] The molecular weight of PEG can range from about 300 to 10,000 MW, about 300 to 5,000 MW, about 500 to 2,000 MW. The molecular weight of PPG can range from about 300 to 5,000 MW, about 300 to 2,000 MW, about 300 to 1,000 MW. The molecular weight of the co-polymer of polyethylene glycol and polypropylene glycol can range from between about 300 to 10,000 MW, 300 to 5,000 MW, and from 300 to 2,000 MW. In embodiments including both the PEG and PPG molecule, the ratio of PEG to PPG can be about 100:1, about 75:1, about 50:1, about 25:1, about 10:1, and about 1:1.
[0073] In general, the modified pigment in FIG. 7 includes, but is not limited to, a styrene co-polymer having the styrene monomer attached covalently to a pigment (hereinafter “modified pigment E”). In addition, the co-polymer includes, but is not limited to, monomer B, monomer C, and monomer D. Monomer B is a hydrophobic monomer, while monomer C is a hydrophilic monomer. The monomers can be randomly arranged or block arranged. It should be noted that prior to reaction, the styrene monomer is an amine styrene monomer, but the amine group is not present in the modified pigment E per the diazonium reaction described below.
[0074] In general, an amine-styrene co-polymer (including monomer B, monomer C, and monomer D) shown in FIG. 7 is reacted with HX (X can be Cl, nitrate, and methane-sulfonic), NaNO 2 , and water. The product of the reaction is a styrene co-polymer having a diazonium cation attached to the styrene benzene ring. Subsequently, the styrene co-polymer having a diazonium cation is reacted with a pigment through a reaction involving the diazonium cation, and the pigment is covalently bonded to the pigment through the styrene benzene ring. Diazonium chemistry and reaction parameters are discussed in U.S. Pat. Nos. 6,723,783; 5,554,739; 5,922,118; 5,900,029; 5,895,522; 5,885,335; 5,851,280; 5,837,045; and 5,922,118, and U.S. patent applications 20030217672 and 20040007152, each of which are incorporated herein by reference.
[0075] The amount of the amine-styrene co-polymer covalently bonded to the surface area of the pigment can range from about 5 to 50%, about 5 to 25%, and from about 5 to 15%.
[0076] Monomer B can include hydrophobic monomers such as, but not limited to, 2-ethylhexyl methacrylate, 2-hydroxyethyl methacrylate, acrylonitrile, vinylidene chloride, methyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, glycidyl, methacrylate, glycidyl acrylate, lauryl methacrylate, dodecyl methacrylate, styrene, chloromethyl styrene, benzyl methacrylate, butadiene, acrylamide, alkyl vinyl ether, silylated butadienes, divinylbenzene, trimethylsilyl methacrylate, alkoxysilane containing vinyl, p-vinylphenol, 2-vinyl quinoline, m-nitrostyrene, 4-hydroxystyrene, p-halomethyl styrene, 4-acetoxy styrene, 4-tert-butoxycarbonyloxy styrene and combination thereof.
[0077] Monomer C can include hydrophilic monomers such as, but not limited to, 2-aminoethyl methacrylate hydrochloride, acrylic acid, methacrylic acid, p-styrene sulfonate, p-methyl amino styrene, vinyl alcohol, p-dimethylamino styrene, vinyl pyridine, 2-methyl-5-vinyl pyridine, maleic anhydride, phenyl maleic anhydride, vinyl amine, vinyl acetate, ethylene-glycol methacrylate, propylene-glycol methacrylate, ethylene-glycol dimethacrylate, propylene-glycol dimethacrylate, trimethylolpropane trimethacrylate, 2-sulfo-1-dimethylethyl acrylamide, 4-styrene sulfonate, 2-sulfoethyl methacrylate, 4-styrene carboxylic acid, N-vinyl pyrrolidone, 1-vinyl imidazole, vinyl benzoic acid, and combinations thereof.
[0078] Monomer D can include monomers such as, but not limited to, acrylate, acrylic acid, maleic anhydride, macro-mers, and combinations thereof.
[0079] The value of q can be from about 1 to 100, about 1 to 75, about 1 to 50, about 1 to 25, and about 1 to 10 monomer units per chain. The value of r can be from about 1 to 100, about 1 to 75, about 1 to 50, about 1 to 25, and about 1 to 10 monomer units per chain. The value of s can be from about 1 to 100, about 1 to 75, about 1 to 50, about 1 to 25, and about 1 to 10 monomer units per chain. The value of t can be from about 1 to 100, about 1 to 75, about 1 to 50, about 1 to 25, and about 1 to 10 monomer units per chain.
[0080] For each of the modified pigments (or the precursor thereof), the monomer including styrene can, in the alternative, include a substituted styrene. Examples of a substituted styrene include, but are not limited to, p-methyl styrene, p-t-butyl styrene, p-chlorostyrene, p-bromostyrene, o-chlorostyrene, o-bromostyrene, 1,3,5-trichlorostyrene, 1,3,5-tribromostyrene, o-fluorostyrene, p-fluorostyrene, pentafluorostyrene, p-hydroxystyrene, p-pentylstyrene, and the like.
[0081] For each of the modified pigments (or the precursor thereof), maleic anhydride can be substituted for another anhydride monomer, such as, but not limited to, succinic anhydride, and itaconic anhydride, in other embodiments.
[0082] The pigment can include, but is not limited to, black pigment-based inks and colored pigment-based inks. Colored pigment-based inks can include, but are not limited to, blue, brown, cyan, green, white, violet, magenta, red, orange, yellow, as well as mixtures thereof.
[0083] The following black pigments can be used in the practice of this disclosure; however, this listing is merely illustrative and not intended to limit the disclosure. The following black pigments are available from Cabot: Monarch™ 1400, Monarch™ 1300, Monarch™ 1100, Monarch™ 1000, Monarch™ 900, Monarch™ 880, Monarch™ 800, and Monarch™ 700, Cab-O-Jet™ 200, Cab-O-Jet™ 300, Black Pearls™ 2000, Black Pearls™ 1400, Black Pearls™ 1300, Black Pearls™ 1100, Black Pearls™ 1000, Black Pearls™ 900, Black Pearls™ 880, Black Pearls™ 800, Black Pearls™ 700; the following are available from Columbian: Raven 7000, Raven 5750, Raven 5250, Raven 5000, and Raven 3500; the following are available from Degussa: Color Black FW 200, Color Black FW 2, Color Black FW 2V, Color Black FW 1, Color Black FW 18, Color Black S 160, Color Black FW S 170, Special Black 6, Special Black 5, Special Black 4A, Special Black 4, Printex U, Printex 140U, Printex V, and Printex 140V Tipure™; and R-101 is available from DuPont.
[0084] The pigment may also be chosen from a wide range of conventional colored pigments. For the purposes of clarification only, and not for limitation, some exemplary colorants suitable for this purpose are set forth below. The color of the second ink formulation can include, but is not limited to, blue, black, brown, cyan, green, white, violet, magenta, red, orange, yellow, as well as mixtures thereof.
[0085] Suitable classes of colored pigments include, for example, anthraquinones, phthalocyanine blues, phthalocyanine greens, diazos, monoazos, pyranthrones, perylenes, heterocyclic yellows, quinacridones, and (thio)indigoids. Representative examples of phthalocyanine blues include copper phthalocyanine blue and derivatives thereof (Pigment Blue 15). Representative examples of quinacridones include Pigment Orange 48, Pigment Orange 49, Pigment Red 122, Pigment Red 192, Pigment Red 202, Pigment Red 206, Pigment Red 207, Pigment Red 209, Pigment Violet 19 and Pigment Violet 42. Representative examples of anthraquinones include Pigment Red 43, Pigment Red 194 (Perinone Red), Pigment Red 216 (Brominated Pyanthrone Red) and Pigment Red 226 (Pyranthrone Red). Representative examples of perylenes include Pigment Red 123 (Vermillion), Pigment Red 149 (Scarlet), Pigment Red 179 (Maroon), Pigment Red 190 (Red), Pigment Violet 19, Pigment Red 189 (Yellow Shade Red) and Pigment Red 224. Representative examples of thioindigoids include Pigment Red 86, Pigment Red 87, Pigment Red 88, Pigment Red 181, Pigment Red 198, Pigment Violet 36, and Pigment Violet 38. Representative examples of heterocyclic yellows include Pigment Yellow 1, Pigment Yellow 3, Pigment Yellow 12, Pigment Yellow 13, Pigment Yellow 14, Pigment Yellow 17, Pigment Yellow 65, Pigment Yellow 73, Pigment Yellow 74, Pigment Yellow 151, Pigment Yellow 117, Pigment Yellow 128, Pigment Yellow 138, and Yellow Pigment 155.
[0086] Such pigments are commercially available in either powder or press cake form from a number of sources including, BASF Corporation, Engelhard Corporation and Sun Chemical Corporation. Examples of other suitable colored pigments are described in the Colour Index, 3rd edition (The Society of Dyers and Colourists, 1982).
[0087] Other examples of pigments include Hostafinet series such as Hostafine™ Yellow GR (Pigment 13), Hostafine™ Yellow (Pigment 83), Hostafine™ Red FRLL (Pigment Red 9), Hostafine™ Rubine F6B (Pigment 184), Hostafine™ Blue 2G (Pigment Blue 15:3), Hostafine™ Black T (Pigment Black 7), and Hostafine™ Black TS (Pigment Black 7), available from Hoechst Celanese Corporation, Normandy Magenta RD-2400 (Paul Uhlich), Paliogen Violet 5100 (BASF), Paliogen™ Violet 5890 (BASF), Permanent Violet VT2645 (Paul Uhlich), Heliogen Green L8730 (BASF), Argyle Green XP-111-S (Paul Uhlich), Brilliant Green Toner GR 0991 (Paul Uhlich), Heliogen™ Blue L6900, L7020 (BASF), Heliogen™ Blue D6840, D7080 (BASF), Sudan Blue OS (BASF), PV Fast Blue B2GO1 (American Hoechst), Irgalite Blue BCA (Ciba-Geigy), Paliogen™ Blue 6470 (BASF), Sudan III (Matheson, Coleman, Bell), Sudan II (Matheson, Coleman, Bell), Sudan IV (Matheson, Coleman, Bell), Sudan Orange G (Aldrich), Sudan Orange 220 (BASF), Paliogen™ Orange 3040 (BASF), Ortho Orange OR 2673 (Paul Uhlich), Paliogen™ Yellow 152, 1560 (BASF), Lithol Fast Yellow 0991K (BASF), Paliotol Yellow 1840 (BASF), Novoperm™ Yellow FG 1 (Hoechst), Permanent Yellow YE 0305 (Paul Uhlich), Lumogen Yellow D0790 (BASF), Suco-Gelb L1250 (BASF), Suco-Yellow D1355 (BASF), Hostaperm™ Pink E (American Hoechst), Fanal Pink D4830 (BASF), Cinquasia Magenta (DuPont), Lithol Scarlet D3700 (BASF), Toluidine Red (Aldrich), Scarlet for Thermoplast NSD PS PA (Ugine Kuhlmann of Canada), E.D. Toluidine Red (Aldrich), Lithol Rubine Toner (Paul Uhlich), Lithol Scarlet 4440 (BASF), Bon Red C (Dominion Color Company), Royal Brilliant Red RD-8192 (Paul Uhlich), Oracet Pink RF (Ciba-Geigy), Paliogen™ Red 3871K (BASF), Paliogen™ Red 3340 (BASF), and Lithol Fast Scarlet L4300 (BASF).
[0088] It should be noted that ratios, concentrations, amounts, and other numerical data may be expressed herein in a range format. It is to be understood that such a range format is used for convenience and brevity, and thus, should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. To illustrate, a concentration range of “about 0.1% to about 5%” should be interpreted to include not only the explicitly recited concentration of about 0.1 wt % to about 5 wt %, but also include individual concentrations (e.g., 1%, 2%, 3%, and 4%) and the sub-ranges (e.g., 0.5%, 1.1%, 2.2%, 3.3%, and 4.4%) within the indicated range.
Part B Examples
[0089] Table 1 of PART B lists ink formulations incorporating embodiments of various modified pigments. Tables 2 and 3 of PART B compare performances of IQ attributes on various glossy media. As shown, the ink formulation including the PEG modified pigment delivers higher gloss and better media independence.
[0000]
TABLE 1
Ink Formulations Having Modified Pigments (Ink
A) vs. Their Traditional Counterparts (Ink B)
Ink ID
Ink A
Ink B
Ink A
Ink B
Light
Light
Black
Black
Gray
Gray
Polyethylene glycols
3
3
3
3
2-P
6
6
6
6
Glycerol
5
5
5
5
Aliphatic diols
4
4
4
4
Hydrocarbon surfactant
0.75
0.75
0.75
0.75
Neopentyl alcohol
0.75
0.75
0.75
0.75
Fluorosurfactant
0.2
0.2
0.2
0.2
Styrene-maleic anhydride co-
0.4
0.4
0.4
0.4
polymer binder
Black Pigment (PB1100/SMA3K-
2.00
0.50
PEG)
Black Pigment (PB1100/SMA3K)
2.00
0.50
DDI water
Balance
Balance
Balance
Balance
pH = 9.1 to 9.4 w/KOH for the vehicle and final inks.
Numbers are in % wt.
pH is about 9.1 to 9.4 with KOH for the vehicle and final inks
Numbers are in % weight
[0000]
TABLE 2
Gloss of the Black Inks
20 Degree
Gloss
20 Degree
60 Degree
with Epx.
Gloss with
Gloss with
Media 1)
Pictorico 2)
Luster Paper 3)
Print Density
Ink A
Ink B
Ink A
Ink B
Ink A
Ink B
(low to high)
Black
Black
Black
Black
Black
Black
Media (white)
44
44
34
34
24
24
Step 1
78
130
107
114
50
51
Step 2
84
150
114
143
59
67
Step 3
88
105
106
110
56
61
Step 4
78
87
113
91
56
56
Step 5
75
111
113
101
58
56
Step 6
77
111
110
103
57
58
Step 7
78
110
112
101
58
59
Step 8
74
113
107
96
58
59
Step 9
77
109
107
106
58
63
Step 10
55
119
106
112
58
64
Step 11
13
124
93
121
48
67
Step 12
8
102
78
136
40
68
Step 13
7
100
71
146
38
69
Step 14 (full
6
99
95
147
42
71
density)
Step 15
7
106
117
145
43
70
Average Gloss
53
107
99
113
50
60
1) Exp. Media: porous silica photo paper, HP in house media.
2) Pictorico: Pictorico Photo Gallery Glossy Paper by AGA chemicals, Inc and Olympus America, Inc.
3) Luster Paper: Epson Premium Luster photo paper.
[0000]
TABLE 3
Gloss of the Light Gray Inks
20 Degree
Gloss
20 Degree
60 Degree
with Epx.
Gloss with
Gloss with
Media 1)
Pictorico 2)
Luster Paper 3)
Ink A
Ink B
Ink A
Ink B
Ink A
Ink B
Print Density
Light
Light
Light
Light
Light
Light
(low to high)
Gray
Gray
Gray
Gray
Gray
Gray
Media (white)
44
44
34
34
24
24
Step 1
83
85
79
62
34
27
Step 2
167
139
135
94
53
42
Step 3
177
181
167
134
69
54
Step 4
175
181
175
166
79
65
Step 5
137
181
152
182
81
72
Step 6
96
181
136
182
81
81
Step 7
73
181
110
183
75
83
Step 8
66
176
90
175
68
82
Step 9
60
151
89
161
61
84
Step 10
34
140
82
155
51
78
Step 11
10
135
91
159
47
80
Step 12
4
64
107
147
48
80
Step 13
2
38
118
127
47
81
Step 14 (full
2
26
132
125
49
80
density)
Step 15
2
16
126
121
50
79
Average Gloss
71
120
114
138
57
68
1) Exp. Media: porous silica photo paper, HP in house media.
2) Pictorico: Pictorico Photo Gallery Glossy Paper by AGA chemicals, Inc and Olympus America, Inc.
3) Luster Paper: Epson Premium Luster photo paper.
[0090] FIG. 8 illustrates a graph comparing a yellow pigment chemically modified with traditional styrene-acrylic polymer (top curve, PY74 yellow pigment, and a yellow pigment chemically modified with SMA-Peg polymer (bottom curve) such as that illustrated in FIG. 3 .
[0091] When the pigment was de-stabilized under various triggering conditions, such as ionic strength and pH, particles started to coagulate. The rate of coagulation was measured by monitoring the time evolution of the flocculation size as determined by dynamic light scattering (DLS). A characteristic coagulation time was derived from fifting the DLS data. The impact of trigger condition and surface modification type on the coagulation time was determined and provides critical insight as to how the pigment coagulation can be controlled to yield optimal print performance.
[0092] The bottom curve (SMA-PEG treated pigment) was more stable than the yellow pigment chemically modified with traditional styrene-acrylic polymer. The stability directly translates into better photo image quality. Photo paper typically triggers the flocculation of pigment dispersion by releasing salt or causing pH changes.
Yellow Pigment and Measurement Details
[0093] Both PY74 pigment dispersions were made into 100 ppm stock solutions. From the stock solution 30 uL was injected into 3 mL of 0.01 mol HCl solution in a 1 cm disposable plastic cuvet to yield a particle concentrations of 1 ppm. After thorough mixing, the cuvet was placed into the DSL instrument and measurement started within 5 seconds. DLS measurements were performed on a BIC ZetaPlus from Brookhaven Instrument Corp. which is equipped with a 30 mW, 670 nm solid state laser. Scattered light at 900 was collected by a single mode fiber optic. Autocorrelation was performed with BI-9000AT Digital Autocorrelator with a user selectable channels up to 512. During this study 200 channels were used with BI-PSDW software.
Synthesis Example for a Representative of Modified Pigment A in FIG. 3:
[0094] A solution was prepared by dissolving poly-styrene-co-maleic anhydride (SMA) (Available from Sartomer Company) in dry DMF. To this stirred solution, at room temperature, under a steady stream of nitrogen gas, was added amine terminated poly-ethylene oxide-co-propylene oxide (e.g., Jeffamine from Huntsman Corporation) and 2-aminoethanethiol hydrochloride as a solid in one portion and then triethylamine was added dropwise. The resultant mixture was heated at about 45° C. for about 30 minutes and then at room temperature for about 4.5 hours. The product was isolated by slowly dropping into vigorously stirred in HCl. After the addition, the mixture was stirred for another 60 minutes and then suction filtered, washed in HCl and then deionized water. The resulting product was briefly air dried to afford a free flowing white solid, which contained moisture. The moisture content could be measured by weight loss after heating at 110° C. for 1 hour.
[0095] The aminoethanethiolated-poly ethylene oxide-co-propylene oxide SMA polymer (SMA-PEG-thio) was dried at 110° C. Results from elemental combustion analysis could be used to characterize the modified polymers. Thiol was measured by titration with DTNB following a modification of Ellman's procedure (Ellman, G. L. (1958) Arch. Biochem. Biophys. 74, 443; Bioconjugate Techniques, Greg T. Hermanson, Academic Press, Inc., 1996, p 88).
[0096] The aqueous dispersion of Black Pearls® 1100 carbon black (available from Cabot Corporation) having attached a 2-(sulfatoethylsulfone) group was prepared according to the procedure described in PCT Publication No. WO 01/51566 to yield a pigment dispersion. This dispersion was added dropwise to the solution of the SMA-PEG-thiol polymer made above (dissolved with NaOH). An additional NaOH was added to raise pH to about 12-13. The resultant mixture was then stirred at about 40-50° C. for about 3.5 hours to give a dispersion of an embodiment of the modified pigment A.
[0097] A sodium acrylate solution was prepared by dissolving acrylic acid into DDI water containing about 11.7 of Na 2 CO 3 . This solution was added to the modified pigment dispersion to “cap” any unreacted thiol groups. Heating and stirring were continued for another 3 hours and the mixture was then allowed to cool to room temperature. The resultant dispersion was then purified by diafiltration to reach a final permeate polymer concentration of less than about 50 ppm.
[0098] Many variations and modifications may be made to the above-described embodiments. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims. | Briefly described, embodiments of this disclosure include ink formulation and modified pigments. One exemplary modified pigment, among others, includes a pigment A represented by the formula in FIG. 3. | 2 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor controlled rectifier which is turned on by a gating signal applied to the gate electrode.
2. Description of the Prior Art
A semiconductor controlled rectifier, which is turned on in response to a gating signal applied to the gate electrode, comprises a semiconductor substrate having at least four layers of P and N conductivity types, disposed alternately; a pair of main electrodes kept in ohmic contact with the outer surfaces of two outermost layers; and a gate electrode connected with one of the four layers of the substrate.
With such a semiconductor controlled rectifier as described above, if a gating signal voltage in the form of a pulse is applied between the gate electrode and one main electrode, with a forward voltage applied to make the other main electrode positive with respect to the one main electrode, then the semiconductor controlled rectifier switches from its OFF state to its ON state. Namely, upon the application of the pulse gating signal, current begins to flow between the two main electrodes, due to the gate current. The transition of the semiconductor controlled rectifier (hereafter referred to also as SCR) from its cut-off state to its conductive state is called "the turn-on" of the SCR. The turn-on of the SCR also takes place, independently of the application of the gating signal voltage, in case where the voltage applied between the main electrodes is higher than the maximum blocking voltage of the device, where the rate at which the voltage rises is great enough while the voltage itself is lower than the maximum blocking voltage, or where the rise in temperature of the device is high. If an SCR is turned on before the application of the gating signal while the voltage applied between the main electrodes is below the maximum blocking voltage of the device, the application of the device to an inverter, a chopper or other electric circuits is impossible. Therefore, it is essential for the SCR that the device is seldom turned on by itself even if the rate at which the voltage applied between the main electrodes rises (hereafter referred to for brevity as the "dv/dt") is high, that is, to improve the dv/dt capability, and that the device is seldom turned on by itself even if the temperature thereof is high. How the SCR is turned on before the application of the gating signal if the dv/dt or the temperature is high, will be explained as follows.
As the forward voltage applied to an SCR is increased, the width of the depletion layer formed on both the sides of the center PN junction which is to be reverse-biased increases. Consequently, a displacement current flows, which increases in proportion to the dv/dt of the forward voltage. On the other hand, the reverse current, approximately proportional to the forward voltage, flows across the center junction. Due to the combined effect of the displacement current and the reverse current, the PN junctions between the intermediate layers and their adjacent outer layers (hereafter referred to as emitter junctions) are forward-biased to induce the injection of carriers from the outer layers to the intermediate ones. The degree to which the emitter junctions are forward-biased is great near the periphery of each emitter junction where the displacement current and the reverse current, which are generated in the center junction that does not overlap with the emitter junction when the layers are projected in a direction perpendicular to the layers, concentrate. Consequently, it happens that the turn-on takes place erroneously in or near the pheriphery of the emitter junction when the dv/dt is high. On the other hand, if the temperature of the SCR is high, the carriers generated by thermal excitation in the depletion layer of the center junction increase so that the reverse current due to the carriers increases across the center junction. Thus, an erroneous turn-on is incurred when the temperature of the device is high, just as in case where the dv/dt is high. In order to improve the dv/dt and temperature capabilities, therefore, it is necessary to prevent the forward biasing of the emitter junctions by the displacement current and the reverse current. One artifice to attain the object is a shorted emitter configuration in which a portion of an intermediate layer is connected by penetrating the adjacent outermost layer with the associated main electrode. This configuration indeed improves the dv/dt and temperature capabilities of the SCR to a considerable extent, but it still cannot be free from the following difficulties. Namely, due to the provision of the gate electrode on the outermost layer, there cannot be only small parts of emitter regions in the neighbourhood of the gate electrode. Accordingly, in order to increase the dv/dt capability, the number of the shorted emitter portions in the area of the outermost layer faced to the gate electrode must be large.
On the other hand, the most important characteristics of the SCR are the initial turn-on area and the spreading of the conducting region in the initial stage of turn-on process. The area and the spreading velocity must be designed to be respectively as large and fast as possible, in order to increase the switching power capability. In order to fulfill this requirement, the number of the shorted emitter portions in the area of the outermost layer faced to the gate electrode must be decreased or preferably be reduced to zero.
According to the conventional method and techniques, as described above, a semiconductor controlled rectifier which has a large initial turn-on area and a high dv/dt and temperature capabilities, cannot be obtained.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a novel SCR which is completely free from the drawbacks of the conventional one. Particularly, the object is to provide a novel SCR in which a large turn-on area is obtained by a small gating signal current and which has a high dv/dt and temperature capabilities.
The feature of the SCR according to the present invention, which can attain the above object, is that the gate electrode and the main electrode kept in contact with the outermost layer adjacent pg,6 to the intermediate layer provided with the gate electrode are electrically connected to each other in the intermediate layer interposed between the gate electrode and the main electrode. Particularly, the feature is that a portion of the gate electrode is approximated to a portion of the main electrode on the intermediate layer so as to provide a bypass for gate current, displacement current and reverse current. With this configuration, the displacement current and the reverse current generated near the gate electrode are collected by the gate electrode and flow into the main electrode through the proximate portion between the gate electrode and the main electrode. Thus, the degradations in the dv/dt and temperature capabilities due to the displacement current and the reverse current generated near the gate electrode can be eliminated.
An SCR using an amplifying gate configuration has been put into practice, in which the gating signal current is amplified by a minor four-layer region formed in the device to obtain a large turnon area by a small gating current and the amplified signal is used as the gate signal for the SCR. The present invention can also be applied to such an SCR.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows in plan an SCR as a first embodiment of the present invention.
FIG. 2 is a cross sectional view taken along line II--II in FIG. 1.
FIG. 3 shows in plan an SCR as a second embodiment of the present invention.
FIG. 4 is a cross sectional view taken along line IV--IV in FIG. 3.
FIG. 5 shows in plan an SCR as a third embodiment of the present invention.
FIG. 6 is a cross sectional view taken along line VI--VI in FIG. 5.
FIG. 7 shows in plan an SCR as a fourth embodiment of the present invention.
FIG. 8 is a cross sectional view taken along line VIII--VIII in FIG. 7.
FIG. 9 shows in plan an SCR as a fifth embodiment of the present invention.
FIG. 10 is a cross sectional view taken along line X--X in FIG. 9.
FIG. 11 shows in plan an SCR as a sixth embodiment of the present invention.
FIG. 12 is a cross sectional view taken along line XII--XII in FIG. 11.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will be described below by way of embodiment with the aid of the attached drawings.
In FIGS. 1 and 2, showing a first embodiment of the present invention, there is shown an SCR having a semiconductor substrate 1 consisting of four layers P E , N B , P B and N E of alternate p- and n-types. The substrate 1 has a pair of main surfaces 11 and 12, disposed parallel and opposite to each other. The layer P E is an emitter layer of p-type conductivity (so referred to hereafter as "P E layer"). The layer N B is a base layer of n-type conductivity (referred to hereafter as "N B layer"), to form a first PN junction J 1 with the P E layer. The layer P B is a base layer of p-type conductivity (also referred to as "P B layer"), disposed adjacent to the N B layer to form a second PN junction J 2 therewith. The layer N E is an emitter layer of n-type conductivity (so referred to hereafter as "N E layer"), formed in the surface of the P B layer with its surface exposed in the main surface and establishes a third PN junction J 3 with the P B layer.
The exposed surface of the P E layer serves as one main surface 11 and the exposed surfaces of the N E layer and the P B layer form the other main surface 12. An auxiliary region N o is a layer of n-type conductivity, formed in the P B layer with its surface exposed in the other main surface 12, isolated from the N E layer by the P B layer and having a smaller area than the N E layer. A first main electrode 2 is kept in low resistance contact with the P E layer in the first main surface 11 and a second main electrode 3 is also kept in low resistance contact with the N E layer and the portion of the P B layer surrounding the N E layer in the second main surface 12. An auxiliary electrode 4 is kept in contact with the surfaces of the auxiliary region N o and the P B layer, isolated from the N E layer. The auxiliary electrode 4 extends along the periphery of the N E layer and the end portions 41 of the auxiliary electrode 4 are embraced by the protruding portions 31 of the second main electrode 3.
A gate electrode 5 is provided on the P B layer between the N E layer and the auxiliary region N o and the gate electrode 5 has a first portion 51 arranged opposite to the auxiliary region N o and second portions 52 integrally formed at the ends of the first portion 51 and protruding toward the auxiliary electrode 4. The electrical resistance between the second portions 52 and the auxiliary electrode 4 is smaller than that between the first portion 51 and the auxiliary region N o . Also, the electrical resistance between the outer peripheries of the end portions 41 and the protruding portions 31 is smaller than that between the other portion of the auxiliary electrode 4 and the N E layer.
The operation of the SCR having such configuration as described above will be described. When a forward voltage is applied between the main electrodes with the first main electrode 2 positive with respect to the second main electrode 3, the second PN junction J 2 is reverse-biased to give rise to displacement current and reverse current. The displacement and the reverse currents flow through the shorted emitter path (not shown) into the second main electrode 3, in the central area of the substrate 1 just beneath the N E layer while in and near the peripheral portion of the substrate 1 where the surface of the P B layer is in contact with the second main electrode 3 these currents flows directly into the second main electrode 3. In and near the portion of the substrate 1 where the surface of the P B layer is in contact with the auxiliary electrode 4, these currents flow into the second main electrode 3 via the auxiliary electrode 4 and the portion of the P B layer between the end portions 41 of the auxiliary electrode 4 and the protruding portions 31 of the main electrode 3. And in and near the portion of the substrate 1 where the surface of the P B layer is in contact with the gate electrode 5, these currents flow into the main electrode 3 via the gate electrode 5, its second portions 52, the P B layer, the auxiliary electrode 4, the end portions 41 of the electrode 4 and the P B layer. Accordingly, the displacement and reverse currents are prevented from forward-biasing the third PN junction J.sub. 3 so that the dv/dt and temperature capabilities can be improved.
Now suppose that a gating signal voltage is applied to make the gate electrode 5 positive with respect to the second main electrode 3 with the first main electrode 2 positive relative to the second main electrode 3. Upon the application of the gating signal voltage between the electrodes 5 and 3, a gate current first flows into the second main electrode, starting at the second portions 52 of the gate electrode 5 and passing through the P B layer, the auxiliary electrode 4, its end portions 41 and the P B layer. This gate current never contributes to the turn-on of the SCR. As such a gate current increases, the voltage drop across the portion of the P B layer between the second portions 52 of the gate electrode 5 and the auxiliary electrode 4 increases. When the voltage drop exceeds the built-in voltage of the PN junction J o between the auxiliary region N o and the P B layer, the gate current begins to flow into the auxiliary region N o across the PN junction J o . Consequently, the gate current properly acts for the four-layer region with the auxiliary region N o as the outermost layer. The four-layer region is then turned on by the gate current to cause the forward current (turn-on current) to flow through the four-layer region so that the forward current flows through the auxiliary electrode 4 into the periphery of the N E layer. This flowing of the current into the N E layer causes the four-layer structure having the N E layer as the outermost layer, i.e., the SCR itself, to turn on.
With this type of turn-on operation, the gate current does not flow through the PN junction J o at first so that some amount of the gate current is consumed uselessly but the dv/dt and temperature capabilities can be improved.
As described above, according to the structure of the SCR shown in FIGS. 1 and 2, high dv/dt and temperature capabilities can be obtained and a large turn-on area can be developed by a small gate current. Moreover, the SCR shown in FIGS. 1 and 2, which is the first embodiment of the present invention, has the following merit. Namely, since the second portions 52 of the gate electrode 5 are disposed opposite to the auxiliary electrode 4, on the surface of the P B layer, the control of the electrical resistance between the two electrodes 4 and 5 is facilitated (that is, reproducibility is improved). For the P B layer has a low impurity concentration and a small concentration gradient and therefore even when the etching is not uniform in the case where the resistance is controlled by etching the P B layer the deviation of the resistance of the resulting device can be made small. That the deviation of the resistance is small, means that SCR's having approximately the same minimum firing gate current and approximately the same dv/dt and temperature capabilities can be easily obtained with high reproducibility.
Nowadays, circuits such as converters for D.C. power transmission, in which a plurality of SCR's are used in series-parallel configuration, are increasing and in each of such circuits it is necessary for well balancing of the voltages and currents distributed to the respective devices that the devices have the same turn-on characteristic. The SCR's according to the present invention are well adapted for such circuits because these SCR's have a smaller finger voltage (i.e., the minimum forward voltage necessary to turn on SCR) than a conventional SCR.
The variations of the embodiment shown in FIGS. 1 and 2 are, for example, as follows. (1) An SCR as shown in FIGS. 1 and 2, wherein the gate electrode 5 is provided on the peripheral portion of the substrate 1 so that the gate electrode 5 may be disposed between the auxiliary region N o and the second main electrode 3. (2) An SCR as shown in FIGS. 1 and 2, wherein the auxiliary electrode 4 is in the shape of ring so as to encircle the N E layer and wherein the electrodes 4 and 5 are disposed opposite to each other on the arbitrary portion of the P B layer. (3) An SCR as shown in FIGS. 1 and 2, wherein the surface of the P B layer exposed in the second main surface 3 is etched down as indicated by the broken line in FIG. 2. (4) An SCR as shown in FIGS. 1 and 2, wherein a portion of the second main electrode 3 is extended beyond the periphery of the N E layer toward the gate electrode 5 so that the extended portion is disposed opposite to the gate electrode 5 on the P B layer.
FIGS. 3 and 4 show an SCR as a second embodiment of the present invention, in which the only difference from the first embodiment is the provision of protrusions 42 toward the gate electrode 5 at the portions of the auxiliary electrode 4 near the ends of the auxiliary region N o .
FIGS. 5 and 6 show an SCR as a third embodiment of the present invention, in which the difference from the first and second embodiments is the provision of a protrusion 43 in the auxiliary electrode 4, extending beyond the auxiliary region N o at the center thereof toward the gate electrode 5. The second and third embodiments can enjoy the same performance as the first embodiment and be modified in the same manner as above.
FIGS. 7 and 8 show an SCR as a fourth embodiment of the present invention. In FIGS. 7 and 8, a semiconductor substrate 21 comprises a pair of main surfaces 211 and 212, four layers P E , N B , P B and N E , and a first, a second and a third PN junctions J 1 , J 2 and J 3 formed between the adjacent layers. The layer N E is so formed in the surface of the P B layer as to expose its surface in the second main surface 212 with the central portion of its surface penetrated by the P B layer. A first main electrode 22 is kept in low resistance contact with the first main surface 211 of the substrate 21 and a second main electrode 23 is kept in low resistance contact with the surface of the N E layer and with the surface of the portion of the P B layer around the N E layer. A gate electrode 24 is kept in contact with the surface of the portion of the P B layer surrounded by the N E layer. The second main electrode 23 has protrusions 231 extending beyond the N E layer toward the gate electrode 24. With this structure, the dv/dt and temperature capabilities can be improved.
FIGS. 9 and 10 show an SCR as a fifth embodiment of the present invention, in which the only difference from the fourth embodiment is the additional provision of a configuration for amplifying the gate current. The structure of this fifth embodiment is as follows. In the SCR shown in FIGS. 7 and 8, a ring-shaped auxiliary region N o is formed in the portion of the P B layer between the N E layer and the gate electrode 24, with its surface exposed in the second main surface 212; an auxiliary electrode 25 is disposed in contact with the surface of the auxiliary region N o and with the surface of the portion of the P B layer contiguous over the outer periphery of the auxiliary region N o ; and the auxiliary electrode 25 has protrusions 251 at the inner periphery thereof, extending beyond the auxiliary region N o toward the gate electrode 24.
FIGS. 11 and 12 show an SCR as a sixth embodiment of the present invention, in which the difference from the fifth embodiment is that the auxiliary region N o is not in the shape of a ring. In this embodiment, one of the protrusions 231 of the second main electrode 23 is approximated to the gate electrode 24 while the other protrusion of the second main electrode 23 is disposed proximate to the auxiliary electrode 25. The difference of the fifth or sixth embodiment from the first one is that the gate electrode is encircled by the N E layer and all these embodiments have almost the same function.
Finally, the present invention will be described numerically. An SCR having such a structure as shown in FIGS. 1 and 2 and having a blocking voltage of 4000 V and a rated average current of 800 A was compared with another SCR having almost the same structure but lacking only the portions corresponding to the second portions 52 of the gate electrode 5. As a result, the dv/dt capability of the former and the latter were respectively 3000 V/μsec and 1400 V/μsec at a junction temperature of 125° C. The minimum firing gate currents of the former and the latter are respectively 30 mA and 15 mA. | A semiconductor controlled rectifier comprising a semiconductor substrate consisting of four layers doped alternately with p- and n-type impurities, a pair of main electrodes kept in ohmic contact with the outermost p- and n-type layers, an N auxiliary region in the intermediate p-type layer with an auxiliary contact thereto, and a gate electrode in contact with the intermediate p-type layer, wherein a portion of the gate electrode is disposed adjacent to the auxiliary region, where there are localized regions forming low resistance paths between the gate electrode and the auxiliary electrode. | 7 |
CROSS-REFERENCE TO RELATED APPLICATION
This application is a U.S. national phase of application PCT/FI96/00316, international filing date May 31, 1996.
BACKGROUND AND SUMMARY OF THE INVENTION
The present invention relates to a method of and apparatus for intensifying the washing of pulp with various washing apparatus. The method and apparatus are particularly well applicable in connection with the so-called Drum Displacer washers, DD washers, by A. AHLSTROM CORPORATION, and also in some wash presses. Because the method and apparatus of the invention are applicable in connection with other washing devices also, different apparatus used in washing are discussed here.
Several types of different washing apparatus and methods are know from the prior art. Diffusers, drum washers and belt washers clearly differ from each other. Pulp is supplied into washing diffusers at a consistency of approx. 10%. The feeding consistency for drum and belt washers is most usually 1-3%. Suction washers, wash presses and pressurized or super-atmospheric washers are examples of drum washers used today.
A conventional suction washer comprises a wire-covered drum revolving in a vat. The shell of the drum comprises under a perforated plate collecting compartments, and each compartment is connected with a tube of its own to a valve system on the shaft at the end of the drum. Filtrate from the valve is guided via a drop leg, or a centrifugal pump providing the required suction, for example to a filtrate tank. Due to the valve arrangement, the influence of the drop leg may be directed appropriately in the desired spots of the web formation.
Web formation in a suction washer takes place as follows: inside the drum revolving in the vat, sub-atmospheric pressure sucking pulp suspension from the vat onto the surface of the drum has been arranged by means of a drop leg or some other device generating suction. When the liquid passes through the drum the fibers in the pulp are collected onto the surface of the drum. The consistency of the suspension in the drum in approx. 0.5-2% and the consistency of the layer thickened onto the drum surface is approx. 10-12%. The web formation area, i.e. the portion of the drum periphery which is in the vat in the fiber suspension, is about 140 degrees. The maximum revolution velocity of the drum is 2-2.5 r/min; at higher revolutions speeds the filtrate collecting compartments and tubes do not have time to be emptied.
Washing is carried out as displacement wash by spraying wash liquid onto the surface of the drum which has risen up from the pulp vat. The sub-atmospheric pressure sucks the wash liquid through the pulp layer and displaces most of the liquid in the pulp. Thus, the displacement area is about 120 degrees. The typical specific square load of a suction washer is approx. 5 BDMT/m 2 /d and the thickness of the pulp web is of the order of 25 mm. In a bleaching plant, the square load of a suction washer is about 8 BDMT/m 2 /d and the web thickness about 30 mm.
A wash press comprises a drum covered with a wire or having a drilled perforated plate shell. Pulp is fed at a consistency of 3-4% and knots and corresponding impurities must have been removed from the pulp prior to the washer. There are compartments provided in the shell of the drum from which filtrate is discharged via a chamber at an end periphery. Also, the drum may be open so that filtrate is collected inside the drum and is discharged via an opening at an end.
The length of the web formation stage is about 90 degrees and that of the displacement stage about 150 degrees. The revolution velocity of the drum is about 2 r/min and the specific square load about 15-20 BDMT/m 2 /d. The consistency of the washed web may rise even up to 35%.
The displacement, however, takes place at a consistency of about 10-15% while the thickness of the pulp web is about 30-50 mm.
An example of a superatmospheric pressure washer is a device disclosed in FI patent publications 71961 and 74752, which is composed mainly of a rotating drum and a stationary shell surrounding the drum. The drum is comprises a perforated cylinder the outer surface of which is provided with 50-60 mm high ribs at about 200 mm spacing. These ribs form with the perforated cylinder surface the so-called pulp compartments. There are filtrate compartments provided inside the cylinder under the pulp compartments, into which the filtrate displaced by the wash liquid is collected. There is a valve arrangement at the end of the cylinder drum substantially at the periphery of the diameter via which valve arrangement the filtrate is discharged and transported further. The washer comprises several, usually 3-4 stages. This means that the wash liquid is reused many times for washing the pulp; thus, the filtrate collected in the filtrate compartments is guided countercurrent from one washing stage to another. Outside the washer drum, as a part of the washer shell, there are wash liquid feed chambers from which the wash liquid is pressed through the perforated plate to the pulp in the pulp compartments to displace the liquid in the pulp.
Web formation and washing of the pulp is carried out by supplying the pulp to be washed via a particular feed box to the pulp compartments. The feed box may thicken the pulp and axial "bars" of the same length as the drum are formed in the pulp compartments. Immediately after the feed point, there is the first washing zone on the drum; there are five separate washing zones in the apparatus described in the publications mentioned. A wash liquid flow is guided to each of these zones and the wash liquid, while being pressed into the pulp layer in the compartments of the washing drum, displaces the liquid in the pulp. As already mentioned above, the filtrates are guided countercurrent from one zone to another. In other words, (cf. FI patent 74752, FIG. 1) clean wash liquid is pumped into the last washing stage and the filtrate displaced by this liquid is taken to the second last washing stage to serve as wash liquid. After the last washing stage, the "pulp bars" are detached from the drum, for example by blowing with pressurized air, and transported further on a transport screw.
The typical specific square load of a pressurized washer of this type with four stages is approx. 2.4 BDMT/m 2 /d. The thickness of the "pulp bar" is about 50 mm and the consistency may rise even up to 15-18%. However, wash water leaking from the compartment decreases the consistency to 10-12%. The consistency of the pulp fed onto the drum may vary between 3,5 and 10%. The drum is rotated at about 0.5-3.0 rpm.
The FI patent 74752 mentioned above (corresponding U.S. Pat. Nos. 4,919,158 and 5,116,423) and the appended FIG. 2 illustrate schematically a little more advanced version of the basic approach of FI patent 71961, by means of which a remarkably better washing result is obtainable than with the basic arrangement illustrated schematically in the appended FIG. 1. In the embodiment of FIG. 2, each washing stage has been divided into two zones so that two washing filtrates with different concentrations are obtained from each stage. These filtrates are recycled countercurrent as illustrated in the Figure. The figure illustrates also how the so-called suction filtrate, i.e. the filtrate extracted from the point between the last washing stage and the pulp discharge, is taken, with the washing filtrate from the latter washing zone of the last washing stage, to the latter washing zone of the second last washing stage to be used as wash liquid.
It is typical of all the above apparatus that at least either the feed of the wash liquid or the treatment of the filtrates or both at the same time show drawbacks. These drawbacks may result in among other things poor washing result. If a washer is found not to be able to reach an adequate washing result the consequence naturally is that a washer with more washing stages or even a washer of a different type is acquired. It may also be necessary to try to solve the problem by increasing the consumption of clean wash liquid which increases the demand of steam in the evaporation plant and the capacity of waste water treatment equipment has to be increased and partly also environmental load increases.
The object of the invention is to solve the problems described above and to introduce arrangements applicable in many different washer types by means of which washing results are achieved which are very close to the optimal washing results obtainable with each washer or process type.
The characteristic features of the method and the apparatus are disclosed in the appended patent claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The method and the apparatus according to the invention is described below in detail by way of example with reference to the accompanying drawings of which
FIG. 1 illustrates schematically the operation principle of a prior art multi-stage washer;
FIG. 2 illustrates schematically the operation principle of another prior art multi-stage washer;
FIG. 3 illustrates a preferred embodiment of the invention:
FIG. 4 illustrates another preferred embodiment of the invention:
FIG. 5 illustrates a conventional way of treating suction filtrate;
FIG. 6 illustrates a way according to a preferred embodiment of the invention, of using suction filtrate;
FIG. 7 illustrates a prior art wash press arrangement;
FIG. 8 illustrates a third preferred embodiment of the invention applied in a wash press arrangement;
FIG. 9 illustrates a prior art washing model;
FIG. 10 illustrates a washing model according to a fourth preferred embodiment of the invention;
FIG. 11 illustrates distribution of concentration of the filtrate as a function of the length of the fiber mat:
FIG. 12 illustrates a washing model according to a fifth preferred embodiment of the invention;
FIG. 13 illustrates a washing model according to a sixth preferred embodiment of the invention;
FIG. 14 illustrates a washing model according to a seventh preferred embodiment of the invention;
FIG. 15 illustrates the influence of the recycling of the suction filtrate and filtrate according to the invention on the purity of the pulp; and
FIG. 16 illustrates the influence of the recycling of the filtrate according to the invention on the purity of the pulp.
DETAILED DESCRIPTION OF THE INVENTION
The operation principle illustrated schematically in FIG. 1 has been applied for example in the so-called DD washer according to FI patent 71961 by A. AHLSTROM CORPORATION. FIG. 1 illustrates how pulp M.sub. in is supplied onto the perforated and moving wire 10 of the apparatus. The wire may be cylindrical, a wash drum, or for example a plane-like surface, a belt washer. The wire 10 has been provided with baffles 12. opposite the wire surface 10, there are stationary wash water feed chambers 14 the bottoms 16 of which, together with the baffles 12 and the wire surface 10, form pulp washing compartments 18. Under the wire surface 10, there are a number of filtrate compartments 20 for collecting the filtrate displaced from the pulp by the wash water. The patent mentioned also describes more closely how the filtrate is transported further from the filtrate compartments 20 via a valve device provided at the end of the drum. The Figure shows that there are four washing stages I-IV in the apparatus. There are also corresponding wash liquid feed chambers 14 I , 14 II , 14 III and 14 IV , and filtrate compartments 20 I , 20 II , 20 III and 20 IV . It is typical of the operation of the apparatus that clean wash liquid W I is brought to the fourth washing stage IV, in which the pulp is cleanest. Filtrate F IV from the fourth washing stage is brought to the third washing stage III to serve as wash liquid, and so on, until the filtrate F I from the first washing stage is directed to waste water treatment, for example to an evaporation plant, and/or it is used as for dilution in a blow tower. As may be understood from the above, the apparatus is capable of replacing four conventional one-stage washers.
FIG. 2 illustrates schematically a more advanced version of the same washer. This washer has been described more closely for example in U.S. Pat. Nos. 4,919,158 and 5,116,423. As the Figure shows, the washer still comprises four washing stages I-IV but each washing stage has been divided internally into two washing zones and filtrates of different concentrations are extracted from these zones. Thus, clean wash liquid W I is brought to the fourth washing stage IV to displace filtrate from the pulp. Because of the fact that in the displacement washing of the type described the concentration of the liquid in the pulp decreases at a relatively even rate from the pulp feed M in to the pulp discharge M out , the filtrate compartment 20 IV of the fourth stage has been divided into two portions 20 IV1 and 20 IV2 , which thus collect filtrates F IV1 and F IV2 of different concentrations. Now these filtrates F IV1 and F IV2 are guided countercurrent, i.e. to the third washing stage III so that the cleanest filtrate, i.e. the filtrate F IV2 , from the latter zone of the fourth stage is guided to the feed chamber 14 III2 of the latter zone of the third stage III to serve as wash liquid. Correspondingly, the more fouled filtrate, i.e. the filtrate F IV1 from the former zone of the fourth stage, is directed to the feed chamber 14 III1 of the former zone of the stage III to be used as wash liquid. Continuing the process by this method to the end of the wash, pulp may be produced which is about 15-30% cleaner than the one produced by the arrangement of FIG. 1.
Generally, it may be stated that the operation principle of a so-called fractionating multi-stage washer of this kind is to receive several filtrates from a washing stage or several washing stages and then to feed the filtrates to a previous washing stage to the zone having the same ordinal number, to be used as wash liquid. Thus, although a washer, in which each stage has been divided into two zones, has been described nothing prevents the stages from being divided into, for example, three zones whereby three different filtrates are received. Of course, it is also possible to divide separate stages into zones in a different way. In other words, for example only one filtrate may be extracted from a washing stage into which two or more wash liquids of different concentrations are supplied. In the so-called DD washer, the first washing stage is often of this kind; thus in some cases the filtrate from the first washing stage is extracted as one fraction to be transported for dilution of pulp and/or chemical recovery.
FIG. 2 also illustrates how, as described in the patents mentioned, the so-called suction filtrate F T obtained from between the last washing stage IV and the pulp discharge M OUT is guided, with the cleaner filtrate F IV2 obtained from the fourth stage IV, to the feed chamber 14 III2 to be used as the wash liquid in the latter zone of the third stage III.
Further, according to the patents mentioned, the filtrates from the first washing stage I are combined, F I , and are guided for example to an evaporation plant or to some other filtrate treatment. The US patents mentioned describe further that yet another filtrate may be obtained when feeding in pulp M in ; this filtrate is discharged from the apparatus separately from the washing stage filtrate F I .
When looking at the process closer, however, the filtrate treatment arrangement of FI patent 74752 or U.S. Pat. Nos. 4,919,158 and 5,116,423 may be made more efficient. Between the last washing stage, which in this embodiment is the fourth washing stage IV, and the pulp discharge point M out , so-called suction filtrate F T is separated from the pulp which is used as wash liquid and referred to in the patents mentioned with reference number 27. The suction filtrate F T comes mainly from the last filtrate compartment and possibly from the thickened pulp. Thus, the composition of the suction filtrate F T resembles most the wash liquid W 1 supplied to the washer.
Firstly, it should be noted that, if there is a suction filtrate flow F T of the kind described, there is less wash liquid flowing into the last washing stage than to the remaining washing stages. Secondly, the suction filtrate F T is cleaner than the pulp leaving the second last washing stage but only a little dirtier than the pulp discharged from the washing process, i.e. the washer.
Thus, in the arrangements of the patents mentioned, the fairly clean suction filtrate F T is taken unnecessarily far upstream.
As illustrated in FIG. 3, the washing process may be made more efficient by supplying the suction filtrate F T to the feed chamber 14 IV1 of the first zone of the last washing stage IV, and not to last zone of the second last washing stage III as described in the FI and US patents. The Figure illustrates how a portions of the filtrate F IV2 from the last zone of the last washing stage IV is extracted and combined with the suction filtrate F T from the thickening stage and the mixture is supplied to the first zone of the last washing stage IV. The Figure also indicates with a broken line that clean wash water W 1 may be supplied, not only to the feeding chamber 14 IV1 of the last zone of the last washing stage IV, but also to form a part of the wash liquid supplied to the feed chamber 14 IV1 of the first zone of the last washing stage IV. By arranging the circulation of the suction filtrate F T in. the way described above the volume of the wash liquid fed into the last washing stage IV and the suction filtrate F T is used for one extra wash.
Another way of circulating the suction filtrate F T is to feed it, combined with clean wash liquid W 1 , to both the feed chambers, 14 IV1 and 14 IV2 , of the last washing stage IV as illustrated in FIG. 4.
It may also be understood that there is a further washing stage subsequent to the last washing stage IV and the suction filtrate F T comes from this extra washing stage.
Performed tests have shown that the new way of circulating of the suction filtrate according to the invention increases the purity of the pulp by 5-35% depending on the number of washing stages performed with the washer. Naturally, the purity increase is the greater the fewer washing stages there are in the washer. In a conventional two-stage washer the washing result improves by about 15-35%.
FIGS. 5 and 6 illustrate the effect of recirculating the suction filtrate in the liquid circulation of a one-stage washer. The numerals in the Figures represent the liquid flows, expressed in cubic meters, used for washing one ton of pulp (ADT; consistency 90%, i.e. one ton of pulp contains 900 kg fibers and 100 kg liquid). Thus, pulp containing 9.1 cubic meters of liquid per one ton of pulp, consistency about 9%, is introduced to the washing; during the web formation 2.5 tons of liquid is removed and the consistency in the washing process is about 13.5%. From this, 1.5 cubic meters of suction filtrate is still removed in the suction stage and thus the discharge consistency of the pulp is about 17.6%. FIG. 5 illustrates a state-of-the-art one-stage washer in which the suction filtrate is combined with the filtrate from the web formation and the washing stage proper and is removed from the apparatus for further treatment of filtrates or for some other use.
FIG. 6 illustrates a case in which the suction filtrate is directed to the beginning of the washing stage; thus, 1.5 cubic meters more of wash liquid per ton of pulp is supplied to the wash itself. As with these amounts the volume of wash liquid is relatively directly proportional to the washing result, it may be stated that in this kind of a case the washing result improves by about 20%.
FIG. 7 illustrates schematically a prior art pulp washing arrangement using a wash press. According to the arrangement of the Figure, pulp is brought for example from a digester or a blow tank of a digester to dilution 30 and diluted to a consistency of approx. 4%. After the dilution the pulp is taken to a thickener 32 in which the pulp is thickened to a consistency of about 10-15% The medium consistency pulp obtained is supplied to a displacement stage 34 into which clean wash liquid is supplied. The pulp is further taken to a thickening stage 38, in which liquid is removed from the pulp so as to raise the consistency to the range of 30-40%. It is typical of the state-of-the-art wash press arrangements that the filtrates F W , F T1 , and F T2 obtained as well from the washing as from the preceding and subsequent thickening stages are combined irrespective of their different concentrations. A portion F 1 of the filtrate mixture F obtained in this way is used in the dilution stage 30 to dilute pulp while the other portion F 2 goes to chemical recovery or some other further use or treatment.
FIG. 8 illustrates a wash press arrangement according to the invention the most significant difference of which compared to the arrangement of FIG. 5 is that the wash press includes two washing stages. The reference numerals used in FIG. 8 correspond to the ones used in FIG. 5; the second washing stage is referred to with numeral 36 and its filtrate with F W2 . When the two washing stages 34 and 36 have been connected the filtrates obtained from the system may be transported countercurrent so that the relatively clean filtrate F T2 from the last thickening stage 38 of the system is used as wash liquid in the first washing stage 34. Clean wash liquid W 1 from an external source is brought only to the second washing stage 36.
It should be noted here that the dilution, thickening and displacement stages mentioned both in connection with FIG. 8 as well as with FIGS. 9 and 10 may be carried out in one and the same apparatus or in separate apparatus located even quite far apart from each other. In practise, the distance between the operations is not of as decisive importance as the method of carrying out the process. In other words, FIGS. 9 and 10 may illustrate for example a prior art washer connection and an improvement made therein. Thus, as in FIG. 9, for example the pulp M in coming from a digester may be diluted to a low consistency for example in a blow tank 40 by using filtrate F TW for this purpose, which may be for example a mixture of filtrate from a thickening stage of a DD washer by A. AHLSTROM CORPORATION, forming the "pulp bar" in the washing space and from a washing stage 44. However, the concentration of the filtrate of the thickening stage mentioned is the same as the concentration of the liquid remaining in the pulp, i.e. the concentration of the liquid used for the dilution has not been paid attention to previously. FI patent 74752, and U.S. Pat. Nos. 4,919,158 and 5,116,423, however, show that the filtrates mentioned are taken separately. Further use or treatment of either of the filtrates is, however, not discussed.
FIG. 10 illustrates a preferred embodiment of the invention improving the process described above. The arrangement of FIG. 9 has been changed so that washing stage filtrate F W and a portion of the filtrate F T from the thickening stage 42 are used for the dilution 40. The rest of the filtrate from the thickening stage 42 is guided to chemical recovery. An arrangement of this kind has been found to improve the washing result by 10-15%. Of course the entire dilution may be carried out with washing stage filtrate if that suffices. In other words, previously filtrates from both the thickening and the washing stages were mixed with each other and after that a portion of this combined filtrate was used for dilution. According to the method of the present invention, only the amount of the filtrate from the thickening stage is taken to the dilution that falls short from the filtrate from the displacement stage. When carried out the way described above the concentration of the filtrate used for the dilution is lower than that of the filtrate used in the prior art arrangement.
The methods described above may still be made more efficient by focusing on the typical concentration distribution of the filtrate which has been illustrated schematically in FIG. 11 as a function of the mat length, i.e. the length of the washing stage. The Figure clearly indicates that the closer the end of the washing stage is the lower the concentration of the filtrate is, i.e. the cleaner the filtrate is. This means that filtrate may be taken from the end of the wash and used even at the beginning of the same washing stage.
FIGS. 12, 13 and 14 illustrate examples in connection with a single-stage washer of how 5-15% of the displacement filtrate from the end part of a washing stage is taken to the beginning of the washing stage. In practise it is possible to bring greater volumes, i.e. a greater portion of the filtrate, to the beginning of the washing stage. Naturally, it is also possible to fractionate the filtrate to be recirculated, i.e. to extract filtrates of several different concentrations and to recirculate them at different points in the beginning of the washing stage, of course the most concentrated first.
FIG. 15 illustrates comparision of the single-stage washer connections illustrated in FIGS. 5, 6, 12, 13 and 14. The horizontal scale depicts the percentage of solid material dissolved from the material, i.e. chemicals and fibers, which on principle should have been removed from the pulp but which the apparatus has not been able to remove. Thus, the scale in the Figure illustrates the range in which 10-13% of the "dirt" is still there. The vertical axis indicates the percentage of washing loss change. Washing losses here mean the amount of dissolved dry solids and chemicals remaining in the liquid in the pulp after the wash. The invention aims at diminishing these washing losses. The initial situation in FIG. 15 is the connection illustrated in FIG. 5, according to which the suction filtrate is removed from the apparatus with other filtrates and it is not returned to the apparatus; thus the descriptor is the horizontal axis of the scale (notice the real zero point of the scale). The 0% curve depicts the influence of the connection illustrated in FIG. 6, i.e. an arrangement in which the entire suction filtrate is returned to the beginning of the washing stage but the filtrate from the displacement washing stage itself is left untouched. The 5% curve depicts the influence of the connection illustrated in FIG. 12, i.e. an arrangement in which 5% of the displacement wash filtrate is recycled with the suction filtrate to the beginning of the washing stage. Correspondingly, the 10 % and the 15% curves represent the effect of the arrangements illustrated in FIGS. 13 and 14. The Figure indicates that if pulp discharged from a conventional washing stage (FIG. 5) contains 11% of the chemicals and the dissolved dry solids, this washing loss may be reduced by about 21% by recycling the suction filtrate to the beginning of the washing stage. This means that the washing loss is reduced to 8.7%. Correspondingly, if the suction filtrate mentioned and also 10% of the displacement wash filtrate is recycled to the beginning of the washing stage the washing loss is reduced by about 30.5%, i.e. the washing loss is reduced to about 7.6%. Thus the washing loss is reduced from 8,69 to 7.645, which means about 12%.
FIG. 16 similarly shows a set of curves the initial situation of which is that the recycling of the suction filtrate has already been employed. By using this set of curves the situation with the first example of the previous Figure may be checked, in which the washing loss was 8.7% and it was further reduced to 7.8% by returning 10% of the filtrate obtained from the end of the washing stage to the beginning of the wash. By choosing 8.7% from the horizontal scale and coming down to the 10% curve, the washing loss reduction may be seen to be about 12% as already calculated above.
Recycling a part of the displacement filtrate as described above requires a filtrate compartment of its own to be provided, one way or another, at the end of the washing stage. A preferred way of effecting this is to use a movable sealing member to separate a part of the actual filtrate compartment so that the volume of the displacement filtrate to be separated may be varied by moving the sealing member. Thus, the volume of the filtrate recycled may be controlled for example according to the running situation of the washer.
As may be understood from the above, the present invention provides a way of making the washing processes of the wood processing industry remarkably more economical and environmentally more friendly compared to the prior art methods and apparatus. It should, however, be born in mind that the embodiments described above are only a few preferred alternative examples of applying the present invention and they do not in any way intend to limit the scope of protection of the invention from the one described in the appended patent claims. Thus, although only examples of single-stage washers have been described the operation of multi-stage washers may be made more efficient by corresponding means. | A method of displacement washing of cellulose pulp achieves substantially optimal results without the consumption of excessive clean wash liquid. In the practice of the method there is at least one washing stage, and a second stage, including a suction, press, and/or thickening stage, following the washing stage. Cellulose pulp is fed to the washing stage, and then the washed pulp is fed to the second stage. A first filtrate is withdrawn from the second stage and a second filtrate is withdrawn from a washing stage of the at least one washing stage, or the second stage. The first filtrate is directed to the washing stage and the first filtrate is used as washing liquid in the washing stage. For example the washing stage may include a last washing stage in a multi-stage fractionating washer, and the second stage may be in the fractionating washer; and the first filtrate may be directed to the last washing stage of the multi-stage fractionating washer. | 3 |
FIELD OF THE INVENTION
This invention relates to a brake shoe for a bicycle, and more particularly to a bicycle brake shoe which comes into press-contact with a rim of the bicycle wheel to exert braking action thereon.
BACKGROUND OF THE INVENTION
Generally, brake shoes are used mainly for a caliper brake at the bicycle and comprise a shoe body which is elongated in the rotation direction of the wheel rim and which is formed in a rectangular parallelepiped shape having a flat braking surface opposite to the braked surface of the rim. Such brake shoes further include a shoe holder which holds the shoe at the side thereof opposite to the braking surface and which mounts the shoe to each of a pair of brake arms, the shoe body being formed of rubber-like material.
A brake lever is manually operated to actuate the brake arms to allow the shoes to move toward each other and to bring the braking surface of each brake shoe into press-contact with the rim, thereby exerting braking action against rotation of the bicycle wheel.
If a conventional brake shoe, as shown in FIG. 7-(a), is made flat at the braking surface thereof, it is difficult to bring the entire braking surface into press-contact uniformly with the rim, so that surface pressure is not increased with respect to a part of the braking surface to thereby diminish the braking effect to that extent. Also, the braking surface is subjected to surface pressure corresponding in amount only to an input by manually operating the brake lever, in other words, the surface pressure is not more than the input, resulting in less braking effect. The input need only increase in order to raise the surface pressure, but since an increase in the input is limited, it has been impossible to sufficiently raise the surface pressure.
Conventionally, a brake shoe has, as shown in FIG. 7-(b), been proposed which is provided at the shoe body with a plurality of projections each having a braking surface and each being spaced from each other at intervals to form grooves which do not come into contact with each other when braking action is applied.
Such shoe with projections enables the braking surface of each projection to come into press-contact with nearly the entire braked increase in surface of the rim, but the surface pressure is small in percentage. Also, a large space is formed between the rim and the groove so that rain water stays in the space and enters onto the braking surface of each projection to cause a slip between the braking surface of the projection and the braked surface of the rim, thereby resulting in diminished braking effect on a rainy day. Also, the conventional brake shoe occasionally generates noises in good weather.
SUMMARY OF THE INVENTION
In light of the above problems, this invention has been designed. An object of the invention is to provide a brake shoe whose braking surface has slits which divide the brake shoe into parts easily elastically deformable, so that each part at the shoe body, when the braking action is exerted, is deformed and rises at its rear edge in the rotation direction of the rim as a result of rotation thereof, thereby enabling the surface pressure at the braking surface to be greatly increased, preventing rain water from staying between the rim and the braking surface, and ensuring drainage by the rear edge of each shoe part. Also, noise-generation at the brake shoe in good weather is lessened.
To achieve the above objective, the shoe body of the invention is provided at the braking surface with at least one slit extending transverse to the longitudinal dimension of the shoe body and extending inwardly halfway toward the portion of the shoe body held by the holder.
The provision of slits on the braking surface facilitates elastic deformation in a portion of the shoe body at the braking surface side thereof, so that the rear edge at each part of the shoe body at the braking surface side is elastically upwardly deformed so as to stick to the wheel rim, and the side surfaces of the slits contact each other. Hence, larger surface pressure exceeding the input is applied to the rear edge during the braking action and the rear edge ensures drainage of rain water from the inner surface of the rim, allowing no rain water to stay in the slits, resulting in that, on a rainy day, the braking effect is greatly increased to ensure safety in operating the bicycle. Also, since the slits make the braking surface side portion of the shoe body easily deformable, noise generation in good weather is able to be reduced.
The above and further objects and novel features of the invention will be more fully apparent from the following detailed description when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partially cutaway perspective view illustrating one embodiment of a brake shoe of the invention,
FIG. 2 is a plan view of the FIG. 1 embodiment,
FIG. 3 is an illustration of the shoe in condition of exerting the braking action,
FIGS. 4-(a) to -(h) are schematic views illustrating various kinds of slits at a shoe body of the invention,
FIG. 5 is a perspective view of a modified embodiment of the invention,
FIG. 6 is an illustration of the shoes of the invention assembled in a cantilever type caliper brake for the bicycle, and
FIGS. 7-(a) and -(b) are illustrations of conventional brake shoes respectively.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIGS. 1, 2 and 6, a shoe used for a cantilever type caliper bicycle brake is shown. The brake shoe comprises a shoe body 2 formed in the shape of a rectangular parallelepiped having a braking surface 1 flat and opposite to the braked surface of the rim R and a holder 3 supporting the shoe body 2 at the side of shoe body 2 opposite to the side thereof facing braking surface 1 and mounted to each of pair of brake arms A. Shoe body 2 is formed of rubber-like material and has a stepwise trapezoidal cross section. Shoe body 2 has a longitudinal half at the side thereof held by holder 3, which is formed as a held portion 21 held by the holder 3.
The holder 3 comprises a holder body 31 having a rectangular base and four vertical segments rising therefrom and a mounting shaft 32 projecting outwardly from the base. Shoe body 2 is held at the held portion 21 into a box of the holder 3, and the mounting shaft 32 is mounted to each brake arm A by use of a mounting means, such as a nut N. A brake lever (not shown) is manually operated to actuate the arms A through a control wire W provided across the brake lever and each arm A, so that the shoe body 2 is brought into press-contact at the brake surface 1 with the braked surface of rim R.
In the embodiment of FIGS. 1 and 2, the shoe body 2 is provided with five slits 4 at the lengthwise central portion of braking surface 1, the slits 4 each extending perpendicularly to the longitudinal direction of the braking surface 1 and extending inwardly perpendicularly toward the held portion 21 held by the holder 3 and being very minute (approximately zero) in width. The upper half of shoe body 2 is divided by the slits 4 into two shoe parts 22 and 23 larger in thickness and formed at both ends of shoe body 2 and four shoe parts 24 to 27 smaller in thickness and spaced at uniform intervals.
Each slit 4, which is about 2 to 5 mm in depth, is largely affected by the material of which shoe body 2 is formed, thereby being not particularly defined. Also, it is preferable that a large number of slits 4 are provided, in which the slits 4 each are provided in pitch intervals of 1 to 3 mm.
Now, in the above described construction of the shoe, when the brake lever is operated to actuate each brake arm A to bring the braking surface 1 of shoe body 2 into press-contact with the braked surface of rim R, the shoe parts 22 to 27, which are made elastically deformable by the slits 4, are deformed to rise at their rear edges in the rotation direction F of the rim so as to stick thereto, thereby increasing the surface pressure at the rear edges by an amount more than an input by manual operation. Hence, the rear edge of each part 22-27, which applies a larger surface pressure to the braked surface of the rim, ensures drainage therefrom, and prevents rain water from staying in the slits 4, thereby providing improved safety in the bicycle's running during a rainy day. In addition, the drainage from each edge is discharged to the exterior through narrow gaps K, each surrounded by adjacent rear edges, the braking surface of each part 22-27 and the braked surface of rim R, as shown in FIG. 3.
Also, the braking surface side portion at the shoe body 2 is elastically deformable to thereby reduce generation of noise in good weather. In addition, a plurality of slits 4 of 1 to 3 mm in pitch intervals, when provided, can further reduce the generation of noise.
The foremost shoe part 22 in the rotation direction F of rim R is larger in thickness along a lengthwise dimension of shoe body 2 so as to withstand deflection more than other parts 24 to 27, thereby restraining excessive deflection thereof, thus keeping the gaps K always narrow and stable.
An experiment was conducted to compare braking effects in three kinds of shoes, that is, the shoe body 2 having five slits as shown in FIG. 1, a shoe body having no slit as shown in FIG. 7-(a), and a shoe body having slits larger in width and kept open even during the braking action as shown in FIG. 7-(b). The experiment was carried out under the following conditions: The caliper brake provided with the brake shoes was mounted to the bicycle frame, the rim R of the rear wheel and the shoe body 2 were kept wet by sprinkling water thereon, the bicycle was run on a predetermined paved road at constant speed, and the brake lever (not shown) at the bicycle handle was manually operated, whereby a braking distance X(m) required to stop the bicycle after the brake lever was operated, was measured.
The result of the experiment was that for conventional shoes having no slit and shoes having conventional slits larger in width, the braking distance was 31.0 m respectively, but the braking distance for the illustrated embodiment of the invention was 24.3 m, thus providing a braking distance which is reduced by about 25%.
Under the same experimental conditions, an experiment was conducted on brake shoes having various kinds of slits 4 and the braking distances were obtained as shown in the following table:
TABLE 1__________________________________________________________________________Slit 4 Lengthwise Location at BreakingSlit Width Slit Braking Widthwise Reference Distance ×B Number Surface 1 Shape Drawing (m)__________________________________________________________________________0 5 Near the Straight FIGS. 1 and 2 24.3 CenterMax. Value 2 Uniformly " FIG. 4-(a) 24.3B1 DividedB1/2 1 Uniformly " FIG. 4-(b) 24.1 Divided" 2 Uniformly " FIG. 4-(c) 24.4 Divided" 3 Uniformly " FIG. 4-(d) 24.9 Divided" 1 Rear Side " FIG. 4-(e) 24.9 in Rotation Direction F" 1 Front Side " FIG. 4-(f) 27.3 in Rotation Direction F" 1 Centra1 Rearward FIG. 4-(g) 24.7 Portion Chevron Shape in Rotation Direction FConventiona1 No Slit FIG. 7-(a) 31.0Conventiona1 Slit larger FIG. 7-(b) 31.0in Width (Width > B1)__________________________________________________________________________
In detail, the brake shoe having five slits each virtually zero in width and provided as shown in FIGS. 1 and 2, obtained a braking distance X of 24.3 m; that having two slits which are relatively larger in width and of the maximum values B1 in width during no braking action, which contact at the braking surface 1 during the braking action, and are provided as shown in FIG. 4-(a), obtained a braking distance of 24.3 m; and shoes having one, two and three slits each having a width half of the maximum value B1 and provided as shown in FIGS. 4-(b), -(c) and -(d), obtained a braking distance of 24.1 m, 24.4 m and 24.9 m respectively. Also, the brake shoe 2 each having only one slit 4 of B1/2 in width and provided as shown in FIGS. 4-(e) and -(f), obtained braking distances X of 24.9 m and 27.3 m respectively, and a shoe having only one slit of B1/2 in width and formed in a V-like shape oriented rearwardly in the rotation direction F of rim R and provided as shown in FIG. 4-(g), obtained a braking distance of 24.7 m.
From the experimental results, it is apparent that
(1) slit 4 can be set in width between very close to zero and the maximum value B1, in other words, the width of slit 4 is not defined or limited to be very close to zero, but can be selected in a value range from very close to zero to the maximum value B1 which is to be zero due to contacting of the adjacent slit walls when the braking action is exerted,
(2) one through five slits are preferred, with the foremost shoe part in the rotation direction F of rim R being made larger in thickness along a lengthwise dimension of the shoe body 2 than the thickness of the other shoe parts, thereby preventing excessive deflection thereof in order to obtain greater braking effect,
(3) it is preferable that the slits, as shown in FIGS. 4-(a) to -(f), be formed in straight lines extending widthwise of the overall braking surface 1, in a V-like or U-like shape provided widthwise of the same and oriented rearwardly in the rotation direction F of rim R as shown in FIG. 4-(g), or in inclined lines with respect to the rotation direction F of the same, and
(4) the slits 4 extend inwardly toward the held portion 21 perpendicularly from the braking surface 1, but may alternatively be inclined therefrom with respect to the rotation direction F of rim R, in which the slits 4 are preferred to incline rearwardly relative to the rotation direction F. Thus, the braking distance of 22 m was obtained and the braking effect was greater.
Alternatively, the shoe body 2 may comprise a plurality of projections 28 each having a braking surface 11 and spaced so as not to contact with each other even during the braking action, the projections 28 being all or partially provided with slits 4.
Also, this invention may of course be applicable to a side-pull or center-pull type caliper brake and a rim brake.
Although several embodiments have been described, they are merely exemplary of the invention and not to be construed as limiting, the invention being defined solely by the appended claims. | A bicycle brake shoe for making press contact with a bicycle wheel rim to apply a braking force thereto. The brake shoe includes a shoe body which is elongated in the rotation direction of the wheel rim and which has a braking surface opposite to the braked surface of the rim. The shoe body also includes at least one slit extending in a direction transverse to the longitudinal dimension of the braking surface and extending inwardly into the shoe body to a predetermined depth. | 5 |
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 11/279,266, filed Apr. 11, 2006, the disclosure of which is incorporated by reference herein in its entirety.
TRADEMARKS
IBM® is a registered trademark of International Business Machines Corporation, Armonk, N.Y., U.S.A. Other names used herein may be registered trademarks, trademarks or product names of International Business Machines Corporation or other companies.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to efficiently cooling electronic circuits, and particularly to cooling circuits through the use of heatsinks.
2. Description of Background
Electronic components, such as microprocessors and integrated circuits, must operate within certain specified temperature ranges to perform efficiently. Excessive heat degrades electronic component performance, reliability, life expectancy, and can even cause failure. Heatsinks are widely used for controlling excessive heat. Typically, heatsinks are formed with fins, pins or other similar structures to increase the surface area of the heatsink and thereby enhance heat dissipation as air passes over the heatsink. In addition, it is not uncommon for heatsinks to contain high performance structures, such as vapor chambers and/or heat pipes, to further enhance heat transfer. Heatsinks are typically formed of metals, such as copper or aluminum. More recently, graphite-based materials have been used for heatsinks because such materials offer several advantages, such as improved thermal conductivity and reduced weight.
Electronic components are generally packaged using electronic packages (i.e., modules) that include a module substrate to which the electronic component is electronically connected. In some cases, the module includes a cap (i.e., a capped module), which seals the electronic component within the module. In other cases, the module does not include a cap (i.e., a bare die module).
Bare die modules are generally preferred over capped modules from a thermal performance perspective. In the case of a capped module, a heatsink is typically attached with a thermal interface between a bottom surface of the heatsink and a top surface of the cap, and another thermal interface between a bottom surface of the cap and a top surface of the electronic component. In the case of a bare die module, a heatsink is typically attached with a thermal interface between a bottom surface of the heatsink and a top surface of the electronic component. Bare die modules typically exhibit better thermal performance than capped modules because bare die modules eliminate two sources of thermal resistance present in capped modules, i.e., the thermal resistance of the cap and the thermal resistance of the thermal interface between the cap and the electronic component. Accordingly, bare die modules are typically used to package electronic components that require high total power dissipation.
Heatsinks are attached to modules using a variety of attachment mechanisms, such as clamps, screws, and other hardware. The attachment mechanism typically applies a force that maintains a thermal interface gap, i.e., the thickness of the thermal interface extending between the heatsink and the module. In the case of a capped module, the cap protects the electronic component from physical damage from the applied force. In the case of a bare die module, however, the applied force is transferred directly through the electronic component itself. Consequently, when bare die modules are used, the attachment mechanism typically applies a compliant force to decrease stresses on the electronic component.
Typical methods and designs used to control the thermal interface gap, while not putting excessive mechanical loads onto the module, include many components and are thus complex, expensive and take up valuable real-estate that could be put to better use by packaging more circuit components. Accordingly, there is a need in the art for a smaller, less complex and less expensive module-to-heatsink mounting arrangement.
SUMMARY OF THE INVENTION
The shortcomings of the prior art are overcome and additional advantages are provided through the provision of a module cooling system, comprising, a module with a center in operable communication with a circuit board, a stiffener abutting the circuit board on a side of the circuit board opposite a side at which the module is disposed, a heatsink abutting the module on a side of the module opposite a side at which the circuit board is disposed, a first biasing member biasing the heatsink relative to the stiffener towards the center of the module, a plurality of non-influencing fasteners positionally fixing the heatsink relative to the stiffener, and a second biasing member biasing the circuit board and module towards the heatsink relative to the stiffener.
Further disclosed herein is a method of mounting a module cooling system, comprising, connecting electrically a module with a center to a circuit board, abutting a stiffener to the circuit board on a side of the circuit board opposite a side at which the module is disposed, abutting a heatsink to the module on a side of the module opposite a side at which the circuit board is connected, biasing with a first biasing member the heatsink in a direction towards the center of the module relative to the stiffener, fixing the heatsink relative to the stiffener with non-influencing fasteners, and biasing with a second biasing member the circuit board and module towards the heatsink relative to the stiffener.
Additional features and advantages are realized through the techniques of the present invention. Other embodiments and aspects of the invention are described in detail herein and are considered a part of the claimed invention. For a better understanding of the invention with advantages and features, refer to the description and to the drawings.
TECHNICAL EFFECTS
As a result of the summarized invention, technically we have achieved a solution, which efficiently couples a heatsink to a circuit for dissipation of heat therefrom.
BRIEF DESCRIPTION OF THE DRAWINGS
The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other objects, features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
FIG. 1 illustrates one example of a plan view of a module cooling system disclosed herein;
FIG. 2 illustrates one example of a cross sectional front view of the module cooling system of FIG. 1 taken at arrows 2 - 2 ;
FIG. 3 illustrates one example of a plan view of a biasing spring disclosed herein; and
FIG. 4 illustrates one example of a cross sectional view of a non-influencing fastener positionally fixing a heatsink to a stiffener disclosed herein.
The detailed description explains the preferred embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIGS. 1 and 2 , a module cooling system according to an embodiment of the invention is shown generally at 10 . A bare die module 12 comprising an electronic component such as a semiconductor chip 14 , a module substrate 18 , and an electronic connector 22 generates heat that requires dissipation. The bare die module shown in FIG. 1 is a single-chip module (SCM); however, those skilled in the art will recognize that the spirit and scope of the present invention is not limited to SCMs. For example, those skilled in the art will recognize that the present invention may be practiced using a multi-chip module (MCM) or other electronic components/heat sources. The semiconductor chip 14 is electrically connected to the module substrate 18 in a center 16 of the module 12 . Electronic connector 22 , which electrically connects printed circuit board 24 to module substrate 18 , may be a pin grid array (PGA), a ceramic column grid array (CCGA), a land grid array (LGA), or the like.
Referring to FIGS. 1 and 2 , a module cooling system according to an embodiment of the invention is shown generally at 10 . A bare die module 12 comprising an electronic component such as a semiconductor chip 14 , a module substrate 18 , and an electronic connector 22 generates heat that requires dissipation. The bare die module shown in FIG. 1 is a single-chip module (SCM); however, those skilled in the art will recognize that the spirit and scope of the present invention is not limited to SCMs. For example, those skilled in the art will recognize that the present invention may be practiced using a multi-chip module (MCM) or other electronic components/heat sources. The semiconductor chip 14 is electrically connected to the module substrate 18 in a center 16 of the module 12 . Electronic connector 22 , which electrically connects printed circuit board 24 to module substrate 18 , may be a pin grid array (PGA), a ceramic column grid array (CCGA), a land grid array (LGA), or the like.
In order to dissipate the heat generated in the module 12 a heatsink 28 is pressed against the module 12 with a thermally conductive material therebetween forming a thermal interface 36 . The thermal interface 36 is made of a thermally conductive material such as thermal gel, grease, paste, oil, gas, solid or other material with a high thermal conductivity. Typically, the thermal interface 36 is relatively thin so that it may easily transfer heat away from semiconductor chip 14 and toward the heatsink's base plate 40 . The thickness of thermal interface 36 extending between the bottom of the heatsink's base plate 40 and the top surface of semiconductor chip 14 is referred to as the thermal interface gap 44 . In one embodiment, the thermal interface gap 44 is about 1.2 mil.
In addition to providing uniform heat dissipation for the module 12 the thermal interface gap 44 provides a damping effect. This damping effect reduces the vibration, and other mechanical transient loads, that impacts the heatsink 28 before it reaches the module 12 . The mounting and loading of the heatsink 28 relative to the module 12 is therefore very important and is described in the following embodiments in detail.
A stiffener 50 , made of a strong material such as stamped metal, is abutted to the circuit board 24 on the side opposite of the module 12 . Threaded non-influencing fastener (NIF) standoffs 54 screw into the stiffener 50 through holes 56 in the board 24 thereby fixing the board 24 to the stiffener 50 . Four holes 58 in the corners of the heatsink 28 slidably engage the NIF standoffs 54 and positionally center the heatsink 28 above the module 12 . A spring 62 , as shown in FIG. 3 , slidably engages center cooling fins 66 of the heatsink 28 and is thereby centered relative to the heatsink 28 . The spring 62 includes a threaded hole 70 at its center for receiving a screw 74 . The centering of the spring 62 relative to the heatsink 28 and the centering of the heatsink 28 relative to the module 12 assures that the screw 74 and its receiving threaded hole 70 are centered above the module 12 .
Ends of the spring 62 , as best seen in FIG. 3 , receive heads 78 on heatsink load posts 82 . A first end 86 of the spring 62 has a keyhole 90 , while a second end 94 has a slot 98 . Since the round portion 102 of the keyhole 90 is larger than the head 78 of the lead posts 82 the spring 62 can be placed over the heads 78 of two load posts 82 and then moved relative to the lead posts 82 thereby locking the ends 86 and 94 under the heads 78 . A pair of heatsink load posts 82 threadably engaged with holes 106 in the stiffener 50 , through holes 56 in the board 24 , are positioned apart by the same distance as the ends 86 and 94 of the spring 62 , and are positioned such that the spring 62 fits between the center fins 66 of the heatsink 28 .
The aforementioned structure allows the heatsink 28 to be centrally spring loaded over the module 12 by tightening a screw 74 into the center hole 70 of the spring 62 . The further the screw 74 is screwed into the spring 62 , the more the center of the spring 62 deflects, and the higher the force applied to the heatsink 28 , and, correspondingly, the higher the force between the heatsink 28 and the module 12 . The central location of the force application assures uniformity of pressure of the thermally conductive material and the corresponding uniformity of the thermal interface gap 44 . Several methods may be employed to create and control the force, such as turning the screw 74 a predefined number of rotations, or turning the screw 74 until its head bottoms out against the spring 62 , for example.
The heatsink 28 may be massive enough to require additional structural attachment, to for example the stiffener 50 , than is provided by the spring 62 alone. Therefore, embodiments may lock the heatsink 28 to the stiffener 50 through the use of non-influencing fasteners (NIF) 120 . Referring to FIG. 4 the NIF 120 includes a NIF screw 122 , a resilient member 124 and, optionally, a washer 128 . The NIF screw 122 threads into a threaded hole 132 in the NIF standoffs 54 which are slidably engaged with holes 58 in the base plate 40 of the heatsink 28 . Tightening of the NIF screw 122 causes the resilient member 124 to compress and expand radially outward until it frictionally engages with the hole 58 thereby positionally locking the heatsink 28 to the stiffener 50 . Structurally supporting the heatsink 28 through the NIFs 120 to the stiffener 50 may remove the potentially damaging dynamic loads that the heatsink 28 could place upon the module 12 .
Referring again to FIG. 2 , a biasing load is applied between the stiffener 50 and the circuit board 24 through the raised surface 140 in the stiffener 50 . The flexing of the stiffener 28 , the board 24 or both, generates this biasing load. By locating the raised surface 140 central relative to the module 12 , the biasing load will act to maintain a uniform thermal interface gap 44 . The amount of force created by the raised surface 140 can be accurately set by the design of the raised surface 140 relative to points where the NIF standoffs 54 attach to the stiffener 50 . Additional ribbing of the stiffener 50 or the addition of a separate pad of alternate material (not shown) could also be incorporated to create specific characteristics of the biasing load.
Embodiments of the invention may have some of the following advantages: a first biasing force applied to a heatsink centrally relative to a module, accurate control of the first biasing force, removal of the first biasing force upon completion of the circuit board assembly, structural support of the heatsink to a stiffener in multiple locations, and a continuously applied centrally loaded biasing force after completion of the assembly.
While the embodiments of the disclosed system and method have been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the embodiments of the disclosed system and method. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the embodiments of the disclosed system and method without departing from the essential scope thereof. Therefore, it is intended that the embodiments of the disclosed system and method not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out the embodiments of the disclosed system and method, but that the embodiments of the disclosed system and method will include all embodiments falling within the scope of the appended claims.
While the preferred embodiment to the invention has been described, it will be understood that those skilled in the art, both now and in the future, may make various improvements and enhancements which fall within the scope of the claims which follow. These claims should be construed to maintain the proper protection for the invention first described. | Disclosed herein is a module cooling system, comprising, a module in operable communication with a circuit board, a stiffener abutting the circuit board, a heatsink abutting the module, a first biasing member biasing the heatsink towards the module, a plurality of non-influencing fasteners positionally fixing the heatsink, and a second biasing member biasing the circuit board and module towards the heatsink. Further disclosed herein is a method of mounting a module cooling system, comprising, connecting electrically a module to a circuit board, abutting a stiffener to the circuit board, abutting a heatsink to the module, biasing with a biasing member the heatsink in a direction towards the module, fixing the heatsink with non-influencing fasteners, and biasing with a second biasing member the circuit board and module towards the heatsink. | 7 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to loading of a fibrous stock suspension with calcium carbonate.
[0003] 2. Description of the Related Art
[0004] Several methods for loading chemical pulp fibers with calcium carbonate are already known. A method is described in U.S. Pat. No. 6,413,365 B1, where the fibrous material is transported by way of a supply line together with calcium oxide and/or calcium hydroxide which are contained in the suspension. From there, the fibrous stock suspension is transported into a rotating distribution device. A reaction gas is fed in a ring shaped pattern into the fibrous stock suspension; this causes the formation of calcium carbonate crystals in the fibrous suspension. The calcium carbonate crystals are distributed in the fibrous stock suspension through the rotating distributor device. This process is known as a Fiber Loading Process.
[0005] Additional methods and arrangements for loading fibers in a fibrous stock suspension with a filler or additives are known from German Patent Nos. DE 101 07 448 A1 and DE 101 13 998 A1. With the assistance of these known processes, cigarette paper, cardboard and all types of packaging papers, all types of Kraft sack paper and papers containing fillers can be produced. The following applies to the production of cigarette paper: cigarette paper has a base weight of 16 to 26g/m 2 . It is frequently enhanced with an impressed watermark and should be very thin, capable of glowing combustion, and tasteless. It should also possess good optical values with regard to the brightness. The capability of glowing combustion is usually achieved by impregnation in order to leave an attractive white ash.
[0006] Cigarette paper is normally produced from linen or hemp fibers, cotton, sulfate pulp, paper machine broke, as well as from other fiber sources. The filler content in cigarette paper is between 5% and 40%, whereby 30% is considered as a standard value.
[0007] Packaging papers and cardboards can be divided into three categories: Container board for packaging purposes, container board for applications in the field of consumer packaging and specialized papers such as wallpaper, book spines, etc. Packaging papers are normally produced as multi-ply products having basis weights higher than 150 g/m 2 . The freeness varies from 600 to 50 CSF or 20 to 80° SR, relative to the produced end product.
[0008] Kraft sack papers require a high porosity and a high mechanical strength in order to meet the high demands that occur such as rough handling during the filling process and the duration of their use, as is the case, for example, with cement bags. The paper must be strong enough to absorb impacts and must have an accordingly high energy absorption capacity. The sack paper must also be porous and sufficiently air permeable in order to facilitate effortless filling. Sack papers are produced, for example, from a long fibered Kraft pulp into product having a basis weight of between 70 and 80 g/m 2 , and having a freeness of between 600 to 425 CSF or 20 to 30° SR. In addition, a medium freeness, as described above is strived for. This is usually achieved through high consistency refining whereas in the case of conventional paper grades, for example, graphic papers, low consistency refining is utilized. The result of the high consistency refining is good adhesion of the fibers to each other as well as a high porosity. The sack paper is predominantly produced from bleached and unbleached fibers, whereby a filler content of 5% to 15% may be present in the produced sack paper.
[0009] Filter paper requires a high controlled porosity and pore distribution. It must have a sufficiently high mechanical strength to counteract the flow of the medium that is to be filtered. Filter paper is produced, with a basis weight of 12 to 1200 g/m 2 . For example, an air filter would
[0010] have a basis weight of between 100 and 200 g/m 2 , an oil and fuel filter between 50 and 80 g/m 2 , a foodstuff filter to 1000 g/m 2 , a coffee filter to 100 g/m 2 , a tea bag between 12 and 20 g/m 2 and a vacuum bag between 100 and 150 g/m 2 . All filters are produced from a multitude of fibers, such as chemical pulp fibers, bleached and unbleached fibers, Kraft pulp, DIP (deinked) paper, recycled fibers, TMP (thermo mechanical) paper, etc.
[0011] What is needed in the art is a more efficient, less costly method of loading a fibrous stock suspension.
SUMMARY OF THE INVENTION
[0012] The present invention provides a method including the following process steps:
Feeding of calcium hydroxide in liquid or dry form, or of calcium oxide into the fibrous stock suspension, Feeding of gaseous carbon dioxides into the fibrous stock suspension, Precipitation of calcium carbonate through the carbon dioxide and Refining of the fibrous stock suspension during the loading process.
[0017] The current invention describes a method for the production of fiber loaded precipitated calcium carbonate (FLPCC) and to simultaneously undergo a refining process. The fiber raw material that is to be loaded may consist of recycling paper, DIP (deinked paper), secondary fibers, bleached or unbleached pulp, mechanical pulp, bleached or unbleached sulfate pulp, broke, linen, cotton, and/or hemp fibers (predominantly cigarette paper) and/or any paper raw material that can be utilized on a paper machine, irrespective of whether or not the end product contains a filler that was produced by a precipitation process in batch reactors or by a refining process, or whether talcum, titanium dioxide (TiO 2 ), silicon, etc. are used. The refining process is also referred to as GCC process (GCC=ground calcium carbonate).
[0018] When a fibrous stock suspension is processed with a fiber loading technology a completely new product for application in paper production results. The new product has new and improved characteristics compared to a product according to the current state of the art. The fiber loading technology permits precipitation of a filler, especially calcium carbonate, that is uniformly distributed and adhered to, in and between the paper fibers directly in the stock preparation of a paper mill. It also allows the treated fibrous stock to undergo a fiber treatment in a refiner simultaneously with the precipitation process.
[0019] The process for the production of precipitated calcium carbonate with simultaneous refining with the assistance of the fiber loading combination process occurs according to the process data, which is described in further detail below. In this context please also refer to German Patents DE 101 07 448 A1, DE 101 13 998 A1 and U.S. Pat. No. 6,413,365 B1.
[0020] In accordance with the FLPCC combination process described under the present invention the filler material utilized according to the current state of the art is replaced with the filler material produced according to the fiber loading combination process technology. The range of application of the filler produced with the fiber loading combination process technology extends to applications within the paper production of all paper grades, including cigarette papers, filter papers, Kraft sack paper grades, cardboard and packaging papers that have a filler content of between 1% and 60% and/or a white liner having a filler content of between 1% and 60%. The loaded and produced paper grades can be produced on a paper machine from a recycling paper, deinked paper (DIP), secondary fibers, bleached or unbleached pulp, mechanical pulp, bleached or unbleached sulfate pulp, broke, linen, cotton, and/or hemp fibers (predominantly for cigarette paper) and/or any paper raw material, irrespective of whether or not the end product contains a filler.
[0021] Fibrous stock produced with the fiber loading combination process technology generally possesses a superior dewatering characteristic as compared to a fibrous stock produced according to another method. The improvement in the dewatering capacity is between 5 to 100 ml CSF or 0.2 to 15° SR, depending upon the required freeness. The stock or pulp produced according to the fiber loading process further possesses a low water retention value of 2 to 25%, depending upon the raw material that is used in production. This permits a more effective production of various paper grades, for example, FL (FL=fiber loaded) copy and printing paper of all types, FL coating paper of all types, FL news print of all types and FL cigarette paper of all types, FL B&P paper of all types, FL Kraft sack paper of all types and FL filter paper, since the water in the stock suspension can be removed faster. The stock therefore dries faster.
[0022] In the instance of FL cigarette paper, FL B&P paper, FL Kraft sack paper and FL filter paper, which do not require fillers, the exposed filler can be removed by way of an additionally provided washing process prior to the refining process, following the refining process, after running through the headbox vat or prior to feeding into the paper machine. This applies to the filler that is not deposited in, or on, the fibers and can be washed out accordingly. The fibers themselves will still contain filler, inside and out so that the positive effects of the fiber loading technology can be taken advantage of.
[0023] The fiber loading technology may be utilized, prior to, or after, the refining process, depending on what requirements are put upon the end product.
[0024] Compared to the current state of the art, a higher freeness value can be achieved with the fiber loading combination technology, since up to 50% of refining energy can be saved. This has an especially positive influence with all the paper grades, which pass through a refining process during their production, or which possess a very high freeness value, for example FL-cigarette papers, FL B&P papers, FL Kraft sack papers and FL filter papers. In particular, these are FL
[0025] cigarette papers having 100 to 25 CSF or 68 to 90° SR, FL B&P papers having 600 to 50 CSF or 20 to 80° SR, FL sack papers having 600 to 425 CSF or 20 to 30° SR and FL filter papers having 600 to 350 CSF or 20 to 35° SR.
[0026] The high mechanical strengths in the end product, which are achieved through the high freeness value, positively affect the production of FL cigarette papers, FL B&P papers, FL sack papers and FL filter papers since, due to process based mechanical loads in the various sections of the paper machine. Process based mechanical loads exist in the press section, the dryer section and in the area where the web is wound, the produced intermediate product and the end product, which is to be produced, bears a high mechanical load due to the utilization of winders, rewinders and converting machinery. Great mechanical stresses occur on the paper, especially in the production of cigarette paper, which are also partially attributed to the low basis weight and the utilization of winders.
[0027] More effective drying to a residual moisture content of 1 to 20% permits an increase in efficiency for all paper grades. A higher water retention capacity, i.e. 1 to 25% results in a positive influence upon remoistening, which is lower in the manufacturing process, as well as upon the printability of the produced web. An additional advantage for all paper grades is the greater brightness or the higher optical values of around 15 or more lightness points, which is to be emphasized in the production of all grades of paper and cardboard, with or without a white liner. By using the fiber loading technology the optical values, for example in cigarette papers, are also improved by up to 10 lightness points.
[0028] An additional advantage of fiber loading with the above referenced paper grades is found in that for special applications calendering is provided and in doing so the so-called blackening due to deposits of FL particles in, around, and on, the fibers is suppressed or eliminated through the utilization of the fiber loading process of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawing, wherein:
[0030] FIG. 1 schematically illustrates an embodiment of the elements and flow of the method of the present invention.
[0031] Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrate one preferred embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner.
DETAILED DESCRIPTION OF THE INVENTION
[0032] In accordance with one embodiment of the current invention aqueous fibrous stock material, especially aqueous paper stock, having a consistency of 0.1 to 20%, preferably between 2 and 15% is used as primary a raw material.
[0033] In accordance with the present invention, calcium hydroxide is mixed as the preferred filler into the aqueous fiber stock material, especially into the paper fiber stock, whereby this has a solids content of between 0.01 and 60%. In accordance with the current invention utilization of a source material, other than calcium hydroxide or calcium oxide, for the formation of the filler is also feasible. The calcium hydroxide is added through a static mixer or an intermediate vat. The carbon dioxide is preferably added into a moist fibrous stock suspension having a consistency of 0.1 to 15%, according to the reaction parameters. Calcium carbonate is precipitated in a carbon dioxide gaseous atmosphere.
[0034] The refining process is carried out simultaneously with the fiber loading process in an apparatus known as the crystallizer; a refining energy in the range of between 0.1 and 300 kWh/ton dry paper pulp is applied; a short reaction time of the calcium hydroxide and the carbon dioxide is important in this context. The energy supply or heat volume, or heating of the paper suspension for the production of crystals in various forms is important for the present invention.
[0035] Depending upon the application of the respective reaction machine, aqueous paper stock with a paper content of between 0.01 and 60% is used as the primary raw material.
[0036] An advantageous embodiment of the method of the present invention provides that a refiner, a disperger and/or a fluffer FLPCC reactor are utilized as a reactor and/or a static mixer. The fibrous stock content, especially the paper content used therein is between 0.01 and 15% in the instance of a static mixer; at between 2 and 40% in the instance of a refiner and a disperger and between 15 and 60% in the instance of a fluffer-FLPCC-reactor.
[0037] The current invention provides that the dilution water is supplied prior to, during, or after, the addition of carbon dioxide, calcium hydroxide or calcium oxide. Calcium carbonate precipitates when adding carbon dioxide into a calcium hydroxide solution or suspension. Conversely, the precipitative reaction also occurs, when calcium hydroxide is added to water under a carbon dioxide atmosphere. Diluting water may be added prior to, during, or after, the addition of carbon dioxide or calcium hydroxide. An expenditure of energy of between 0.3 and 8 kWh/t, especially between 0.5 and 4 kWh/t is preferably used for the precipitation reaction.
[0038] Likewise it can be provided that the process temperature is between −15° C. and 120° C., especially between 20° C. and 90° C.
[0039] According to the current invention rhombohedral, scalenohedron and spherical crystals can be formed.
[0040] Advantageously, the crystals measure between 0.05 and 5 μm, especially between 0.3 and 2.5 μm. Static and/or moving, especially rotating mixing elements, may be utilized. The process is carried out in a pressure range of between 0 and 15 bar, preferably between 0 and 6 bar. The pH value is between 6 and 10, preferably between 6.5 and 9.5. The reaction time is advantageously between 0.01 minutes and 1 minute, especially between 0.05 seconds and 10 seconds.
[0041] The current invention is described in further detail below, citing a design example and with the assistance of FIG. 1 , which illustrates a schematic view of an apparatus for loading of a fibrous stock suspension. For the purpose of loading a fibrous stock suspension with calcium carbonate the suspension is transported in a device 1 in a pipe line system that is equipped with control valves 10 and 12 . Control valve 10 is located in a line 14 through which the piping system is connected to a static mixer 16 . Diluting water can be fed to static mixer 16 by way of a valve 18 . Also, the addition of a suspension of calcium hydroxide is controlled by way of an additional valve 22 that is installed in a line 20 . This is supplied by a preparation apparatus 24 , where solid calcium oxide or calcium hydroxide is fed into water. For this purpose water is supplied to preparation apparatus 24 by way of a line that is equipped with a valve 26 . The suspension produced in preparation apparatus 24 is passed into line 20 by a pump 28 .
[0042] The diluted fibrous stock suspension, to which calcium hydroxide was added, flows from mixer 16 into line 30 that is equipped with valve 32 . From line 32 the suspension is immediately fed into a disperger 42 (crystallizer). For the purpose of supplying carbon dioxide, this is connected with a carbon dioxide tank 52 through a line 50 , which is equipped with valves 44 and 46 , and a pump 48 . Carbon dioxide is fed from carbon dioxide tank 52 into disperger 42 in order to produce the desired precipitation reaction of calcium hydroxide and carbon dioxide
[0043] for the formation of calcium carbonate as a filler in the fibers of the fibrous stock. Instead of utilizing a mixer 16 , the calcium hydroxide may also be added from a header tank.
[0044] Line 50 is connected by way of an additional valve 58 with a static mixer 60 whose purpose it is to add additional carbon dioxide to the fibrous stock suspension flowing from disperger 42 through line 64 which is equipped with valve 62 .
[0045] Fibrous stock suspension that is not treated with calcium hydroxide can additionally be fed into blend chest 68 by way of the 12 and line 70 .
[0046] The fibrous stock suspension flows from static mixer 60 into blend chest 68 , which is equipped with a rotor 66 for the purpose of thoroughly mixing the fibrous stock suspension. From blend chest 68 the fibrous stock suspension flows either immediately to a headbox in a paper machine, or it is subjected to additional mechanical processing, for example in a refiner feed chest.
[0047] In addition, a refiner 80 can be installed in the piping system for the purpose of improving the fibrous stock suspension through an additional refining process. Refiner 80 is supplied with fibrous stock suspension by way of a line 82 that branches off of line 30 . From refiner 80 the repeatedly refined fibrous stock suspension is brought through line 84 into line 64 and from there, as described above, into blend chest 68 .
[0048] Provisions can additionally be made that carbon dioxide from carbon dioxide storage tank 52 is supplied to refiner 80 through line 86 that branches off of line 50 and a static mixer 88 that connects line 86 with line 82 .
[0049] The inventive design of the present invention includes loading of a fibrous stock suspension with calcium carbonate that has the advantage, when compared with devices according to the current state of the art, in that machinery for homogenizing of the fibrous stock suspension, such as a screw press, and a conditioning machine for homogenizing of the fibrous suspension (equalizing reactor) is not required. Refiner 80 having a container/vessel additionally takes over the refining process, providing a considerably simpler arrangement of stock preparation compared to the current state of the art. This refining process serves at the same time as an agitation process, in order to deposit the calcium carbonate in the fibers through a shear process.
[0050] In the inventive method, for preparation of the fibrous stock suspension by way of the fiber loading process, calcium hydroxide (lime hydrate, lime milk) is used, which has a solubility in water at 20° C. of 1.65 g/l to 0.7 g/l at 100° C. A pH value of up to 12.6 is achieved, depending upon how closely the concentration of the solution reaches the maximum value. In commercially available lime hydrate concentrations, solids contents of 0 to 60% can be realized, whereby the suspension has a pH-value of 12.6 maximum. The actual volume of lime hydrate in the suspension therefore includes the dissolved component as well as the solids concentration.
[0051] For a suspension containing 20% calcium hydroxide in one liter at 20° C. therefore, a dissolved mass of 1.65 g calcium hydroxide and a solids content of 198.35 g results. Since in the fiber loading process the conversion or reaction speed influences the end product of the FL (fiber loading) process every effort is made to use the lime hydrate for an as short as possible conversion time. This is achieved in that for the production of the lime hydrate calcium oxide (CaO), in a medium particle size range of 0.01 to 100 mm, especially in a size range of 0.05 to 50 mm, is produced in a slaking process.
[0052] While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims. | A method of loading a fibrous stock suspension containing chemical pulp fibers with calcium carbonate including the steps of: adding one of calcium oxide and calcium hydroxide in one of a liquid form and a dry form into the fibrous stock suspension; adding gaseous carbon dioxide into the fibrous stock suspension; precipitating of the calcium carbonate through said carbon dioxide; and refining of the fibrous stock suspension during said precipitating step. | 3 |
CROSS REFERENCES TO RELATED APPLICATIONS
The present invention contains subject matter related to Japanese Patent Application JP 2006-204124 filed in the Japanese Patent Office on Jul. 27, 2006, the entire contents of which being incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a content providing method, a program of a content providing method, a recording medium on which a program of a content providing method is recorded, and a content providing apparatus, which for example can be adapted to provide video contents such as a sport program for a user. The invention is to provide video in which moving image data of high resolution at a high frame rate is partially cut out to form zoomed-in moving image data, the resolution and the frame of the remaining portion are thinned out to generate the moving image data slightly zoomed out, and the zoomed-in moving image data and the moving image data slightly zoomed out are sent, whereby the prevention of jerkiness and a moving image to be out of focus is achieved while an increase in data volume to send is being avoided, and the video slightly zoomed out and zoomed-in video can be selectively provided for a user.
2. Description of the Related Art
Heretofore, in moving image data according to video signals of NTSC (National Television System Committee) and HDTV (High Definition Television), the field frequency is defined to 60 Hz or 59.94 Hz, and in moving image data according to video signals in the PAL (Phase Alternation by Line) mode, the field frequency is defined to 50 Hz. Generally, in the motion picture, the frame frequency is defined to 24 Hz.
In the representation of moving image data according to the field frequency and the frame frequency, image quality deterioration such as out-of-focus moving images and jerkiness is known. Here, the out-of-focus moving image occurs in an imaging system and a display system. The out-of-focus moving image taken place in the imaging system occurs by intermittently shooting a moving subject for a charge storage time period in a certain length. In addition, the out-of-focus moving image taken place in the display system occurs in a so-called hold type display device. Moreover, here, for example, the hold type display device is a device that continuously displays an image in each frame for a single frame period like a liquid crystal display the panel. The out-of-focus moving image taken place in the display system also occurs in a motion picture by projecting a film, and a motion picture by DLP (Digital Light Processing). The out-of-focus moving image taken place in the display system is perceived by the occurrence of a shift of an image on the retina called the retinal slip when a moving object displayed is followed and viewed (SHIKAKU JOUHO SYORI HANDOBUKKU, Asakura Publishing Co., Ltd., p. 393).
Therefore, the out-of-focus moving image taken place in the imaging system can be prevented by shortening the charge storage time period, and the out-of-focus moving image taken place in the display system can be prevented by using a display device on the impulse response side with a short emission time.
However, when the charge storage time period is simply shortened to use the display device on the impulse response side with a short emission time in the conventional field frequency and frame frequency, jerkiness is perceived. Here, jerkiness is a phenomenon that the motion of the subject can be seen discretely when the moving subject is shot. Therefore, in order to prevent the out-of-focus moving image and further prevent jerkiness, it can be thought that it is necessary to increase the frame frequency.
As to a display for moving image data, JP-A-2005-215351 (Patent Reference 1) discloses a configuration in which data is partially cut out to display zoomed-in data.
In relay broadcasting of sports, such as soccer and American football, shooting is shared by a plurality of television cameras, and moving image data obtained by the plurality of the television cameras is keyed for broadcasting. More specifically, in the relay broadcasting, for example, a single television camera shoots the full view of the pitch and the field or a part of the pitch and the field as it slightly zooms out, and the other television cameras zoom in and follow a ball or a particular player. Moreover, in the case in which right after a game is started and then the game is suspended, it is difficult to follow a subject by zoomed-in video, and the video taken by a television camera that slightly zooms out is broadcast.
As to video contents like this, suppose both of video slightly zoomed out and zoomed-in video are provided for a user, two types of video can be selectively displayed or two types of video can be displayed at the same time on the user side, and it can be thought that ways to enjoy video contents are increased.
However, in the case in which both of video slightly zoomed out and zoomed-in video are simply sent, two systems of moving image data have to be sent, causing a problem that it is necessary to send data volume twice as much as that of a single system of moving image data.
For one of schemes to solve this problem, for example, a method can be thought in which the scheme described in JP-A-2005-215351 is adapted to cut out zoomed-in video of video slightly zoomed out and the video is offered. According to this scheme, it is enough to send a single system of moving image data. Thus, the data volume to send can be decreased more than the case in which two systems of moving image data of video slightly zoomed out and zoomed-in video are simply sent.
However, even though this is done, when it is intended to prevent out-of-focus moving images and jerkiness described above, it is necessary to send a single system of moving image data that displays video slightly zoomed out at a high frame rate, causing a problem that the data volume to send is increased.
SUMMARY OF THE INVENTION
Thus, it is desirable to provide a content providing method, which can prevent an out-of-focus moving image and jerkiness while an increase in the data volume to send is being avoided, and can selectively provide video slightly zoomed out and zoomed-in video to a user, a program of a content providing method, a recording medium on which a program of a content providing method is recorded, and a content providing apparatus.
An embodiment of the invention is directed to a content providing method including the steps of: outputting moving image data of video contents; selecting moving image data in a partial area from the moving image data of the video contents, and outputting zoomed-in moving image data; thinning out frames and pixels of the moving image data of the video contents except at least the partial area, and outputting moving image data slightly zoomed out; and outputting the zoomed-in moving image data and the moving image data slightly zoomed out.
An embodiment of the invention is directed to a program of a content providing method including the steps of: outputting moving image data of video contents; selecting moving image data in a partial area from the moving image data of the video contents, and outputting zoomed-in moving image data; thinning out frames and pixels of the moving image data of the video contents except at least the partial area, and outputting moving image data slightly zoomed out; and outputting the zoomed-in moving image data and the moving image data slightly zoomed out.
An embodiment of the invention is directed to a recording medium on which a program of a content providing method of providing video contents is recorded, the program of the content providing method including the steps of: outputting moving image data of video contents; selecting moving image data in a partial area from the moving image data of the video contents, and outputting zoomed-in moving image data; thinning out frames and pixels of the moving image data of the video contents except at least the partial area, and outputting moving image data slightly zoomed out; and outputting the zoomed-in moving image data and the moving image data slightly zoomed out.
An embodiment of the invention is directed to a content providing apparatus including: a moving image data output part configured to output moving image data of video contents; a moving image data selecting part configured to select moving image data in a partial area from the moving image data of the video contents, and to output zoomed-in moving image data; a thinning part configured to thin out frames and pixels of the moving image data of the video contents except at least the partial area, and to output moving image data slightly zoomed out; and a data output part configured to output the zoomed-in moving image data and the moving image data slightly zoomed out.
An embodiment of the invention is directed to a content providing apparatus which is connected to a network, and is configured to display moving image data outputted from a host unit, wherein the host unit includes: a moving image data output part configured to output moving image data of video contents; a moving image data selecting part configured to select moving image data in a partial area from the moving image data of the video contents, and to output zoomed-in moving image data; a thinning part configured to thin out frames and pixels of the moving image data of the video contents except at least the partial area, and to output moving image data slightly zoomed out; and a data output part configured to output the zoomed-in moving image data and the moving image data slightly zoomed out to the network, and the content providing apparatus includes: an input part configured to input the zoomed-in moving image data and the moving image data slightly zoomed out from the network; and a display part configured to selectively display the zoomed-in moving image data, the moving image data slightly zoomed out inputted in the input part.
According to the configurations above, the zoomed-in moving image data and the moving image data slightly zoomed out are outputted, and then the zoomed-in moving image data and the moving image data slightly zoomed out are used to provide the zoomed-in video and the video slightly zoomed out to a user. In addition, the moving image data in the partial area selected from the moving image data of the video contents is the zoomed-in moving image data, and the moving image data slightly zoomed out is generated from the moving image data of the video contents except at least the partial area. Therefore, the data volume to send can be decreased more than the case in which two systems of moving image data, video slightly zoomed out and zoomed-in video, are simply sent. In addition, the moving image data slightly zoomed out for the video slightly zoomed out is generated by thinning out frames and pixels. Therefore, the data volume to send can be decreased more than the case in which the moving image data of the video contents is directly sent and the zoomed-in video and the video slightly zoomed out are generated on the receiving side to prevent out-of-focus motion and jerkiness, and out-of-focus moving images and jerkiness can be prevented.
According to the embodiments of the invention, out-of-focus moving images and jerkiness can be prevented while an increase in the data volume to send is being avoided, and the video slightly zoomed out and zoomed-in video can be selectively provided to a user.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a block diagram depicting a video content providing system according to Embodiment 1 of an embodiment of the invention;
FIGS. 2A and 2B show a plan view illustrative of zoomed-in video by the video content providing system shown in FIG. 1 ;
FIG. 3 shows a flow chart depicting the process steps of a processor part of the video content providing system shown in FIG. 1 ;
FIG. 4 shows a block diagram depicting the details of a user terminal unit the video content providing system according to Embodiment 1 of an embodiment of the invention;
FIGS. 5A to 5D show a plan view depicting the display screen of a user terminal unit shown in FIG. 4 ;
FIG. 6 shows a flow chart depicting the process steps of the user terminal unit shown in FIG. 4 ;
FIG. 7 shows a flow chart depicting the process steps of moving image data in the video content providing system according to Embodiment 1 of an embodiment of the invention; and
FIG. 8 shows a block diagram depicting a video content providing system according to Embodiment 2 of an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the invention will be described in detail with reference to the drawings.
Embodiment 1
1. The Configuration of the Embodiment
FIG. 1 shows a block diagram depicting a video content providing system according to Embodiment 1 of the invention. In this video content providing system 1 , a host unit 2 is connected to a user terminal unit 3 via a home network 4 . As shown in FIG. 2A , video contents are provided from the host unit 2 to the user terminal unit 3 so that video slightly zoomed out V 1 and the zoomed-in video V 2 that is partially cut out of the video slightly zoomed out V 1 can be selectively displayed, and the video contents are provided from the user terminal unit 3 for a user. From a user, the video content providing system 1 accepts specifying the area to generate the zoomed-in video V 2 from the video slightly zoomed out V 1 in the user terminal unit 3 .
Here, for example, in the host unit 2 , a recording/reproducing device 11 is a large capacity hard disk device or an optical disk player, which outputs moving image data SVH that is video contents under control done by a processor part 16 . Here, the moving image data SVH is formed of video signals of high resolution at a high frame rate. The moving image data SVH is moving image data of a high frame rate that can prevent out-of-focus moving images and jerkiness even though the area of video data is partially cut out to display the zoomed-in video V 2 on the full screen in the user terminal unit 3 . Suppose the frame frequency is 50 frames per sec or greater, out-of-focus moving images and jerkiness can be deceased in moving image data, and suppose the frame frequency is 120 frames per sec or greater, out-of-focus moving images and jerkiness can be made difficult to perceive. In this embodiment, the recording/reproducing device 11 outputs moving image data SVH at a frame frequency of 120 frames per sec.
In addition, the moving image data SVH is high resolution moving image data that can display the zoomed-in video V 2 on the full screen in sufficient resolution even though the area of video data is partially cut out to display the zoomed-in video V 2 on the full screen in the user terminal unit 3 . Preferably, it is desired that the resolution of the moving image data SVH is that of VGA (Video Graphics Array) or greater, and more preferably, it is desired that the resolution is that of HDTV (High Definition Television) or greater.
A thinning part 12 thins out the pixels and frames of the moving image data SVH, and outputs moving image data SV 1 . Here, in the video content providing system 1 , since the area of video data is partially cut out from the moving image data SVH to generate the zoomed-in video V 2 , in the case in which the moving image data SVH is displayed on the full screen in the user terminal unit 3 (V 1 ), the motion of the subject naturally becomes smaller and the allowance for out-of-focus moving images and jerkiness becomes greater than the case in which the partial area is displayed on the full screen in the user terminal unit 3 . In addition, as to the resolution, in the case in which the moving image data SVH is displayed on the full screen in the user terminal unit 3 , the allowance becomes greater than the case in which the partial area is displayed on the full screen in the user terminal unit 3 . The thinning part 12 thins out the frame of the moving image data SVH by the allowance that is greater with respect to out-of-focus moving images and jerkiness. In addition, it thins out the pixel of the moving image data SVH by the allowance that is greater with respect to the deterioration of resolution. Moreover, the thinning out of the pixels and the frames can be set to various thinning rates when sufficient characteristics can be secured in practice.
An encoder 13 compresses the moving image data SV 1 outputted from the thinning part 12 , and generates encoded data DV 1 . In addition, for the data compression, schemes such as MPEG (Moving Picture Experts Group)-4 can be adapted. The host unit 2 provides the encoded data DV 1 to the user terminal unit 3 as the video slightly zoomed out V 1 .
An interface (I/F) 14 sends the encoded data DV 1 outputted from the encoder 13 to the home network 4 together with encoded data DV 2 outputted from an encoder 15 . In addition, the interface receives various requests RQ from the user terminal unit 3 via the home network 4 , and notifies the received request RQ to a processor part 16 , for example. Here, in this embodiment, the request RQ from the user terminal unit 3 is to specify the area for cutout of the zoomed-in video V 2 from the video slightly zoomed out V 1 .
A selecting part 17 selects the moving image data in a certain area from the moving image data SVH in accordance with the instruction from the processor part 16 , and outputs the zoomed-in moving image data SV 2 that shows the zoomed-in video V 2 .
As similar to the encoder 13 , the encoder 15 compresses the zoomed-in moving image data SV 2 , and outputs the resulting encoded data DV 2 .
The processor part 16 is a processor unit that, executes a program recorded on a recording unit, not shown, and controls the operation of the host unit 2 . In addition, in the embodiment, although the program is installed in the user terminal unit 3 in advance and offered, instead of this, the program may be offered by recording it on a recording medium such as an optical disk, a magnetic disk, and a memory card, and the program may be offered by downloading it via a network such as the Internet. In addition, the thinning part 12 , the encoders 13 and 15 , and the selecting part 17 maybe configured as a functional block of the processor part 16 .
In other words, when the processor part 16 is requested by the user terminal unit 3 for notification, of reproducible video contents, it notifies the titles of the video contents recorded in the recording/reproducing device 11 to the user terminal unit 3 . In addition, when the user terminal unit 3 instructs reproducing the video contents by this notification, the processor part 16 controls the operation of the recording/reproducing device 11 so as to reproduce the video contents instructed by the user terminal unit 3 . In addition, the processor part 16 in turn processes the moving image data SVH of the video contents outputted from the recording/reproducing device 11 in the thinning part 12 and the encoder 13 , and provides it to the user terminal unit 3 . Thus, the processor part 16 provides the video slightly zoomed out V 1 to the user terminal unit 3 .
AS described above, when a request for the zoomed-in video V 2 is obtained from the user terminal unit 3 in the state in which the video slightly zoomed out V 1 is provided to the user terminal unit 3 , the processor part 16 starts process steps shown in FIG. 3 . In other words, when the processor part 16 starts the process steps, the process goes from Step SP 1 to Step SP 2 . Here, the processor part 16 suspends the reproduction of the video contents in the recording/reproducing device 11 , and sets the operation of the thinning part 12 so that the moving image data of the frame currently being outputted is repeatedly outputted. Thus, the processor part 16 switches the video contents currently being provided to a still image. In addition, the output of the video contents in the still image may be controlled by the recording/reproducing device 11 .
In this state, the processor part 16 accepts the setting of the partial area to generate the zoomed-in video V 2 from the user terminal unit 3 . In addition, here, for example, the acceptance of the setting is executed by accepting the input of the center coordinates of the partial area in the still image currently provided to the user terminal unit 3 . In addition, the acceptance of the partial area is eventually to specify a subject to be displayed in the zoomed-in video V 2 . Therefore, instead of the center coordinates of the partial area, the setting of the partial area may be accepted by the coordinates of subject to be displayed in the zoomed-in video V 2 . In addition, for example, the setting of the partial area may be accepted by specifying the end point in the diagonal direction. The processor part 16 analyses the moving image data SV 1 outputted from the thinning part 12 , and detects a target subject for tracking in the partial area.
Subsequently, the processor part 16 goes to Step SP 4 , instructs the recording/reproducing device 11 to restart reproducing the video contents, and restarts providing the video contents in moving images. In addition, in the subsequent Step SP 5 , it analyzes the moving image data SV 1 outputted from the thinning circuit 12 , and starts tracking the subject detected in Step SP 3 . In addition, here, for example, for the detection and tracking of the subject, various schemes may be adapted such as the detection and tracking of the subject using template matching, and the detection and tracking of the subject using characteristic points. Moreover, the processor part 16 instructs the selecting part 17 and the encoder 15 to start the operations, and instructs starting the output of the zoomed-in video V 2 .
Subsequently, the processor part 16 goes to Step SP 6 , and here, it determines whether the subject is successfully tracked in the subsequent frame. Here, when it is successful, the processor part 16 goes from Step SP 6 to Step SP 7 . Here, from the movement of the target subject for tracking that is detected in the moving image data SV 1 and specified by the user from the current frame to the subsequent frame, the movement between the successive frames of the subject in the moving image data SVH before thinned out is computed. In addition, in this embodiment, the movement of the subject from the current frame to the subsequent frame detected in the moving image data SV 1 is divided at the ratio of the frame frequency between the moving image data SV 1 and the moving image data SVH to compute the movement in the moving image data SVH.
Subsequently, the processor part 16 goes to Step SP 8 . Based on the movement computed in Step SP 8 , it computes the coordinates of the partial area to be cut out of the moving image data SVH so that the partial area is moved as it follows the motion of the target subject for tracking for every frame of the moving image data SVH in the period from the current frame to the subsequent frame of the moving image data SV 1 , and in turn notifies the coordinates of each of the computed frames to the selecting part 17 . Thus, as depicted by signs V 2 - 1 to V 2 - 3 shown in FIG. 2B , the host unit 2 varies the partial area to generate zoomed-in video so as to track the movement of the subject, and generates the moving image data SV 2 from the zoomed-in video V 2 .
In addition, in the process in Step SP 8 , the processor part 16 restricts the movable range of the partial area to generate the zoomed-in video V 2 within a fixed range, and assures that the partial area is not off the picture frame of the moving image data SVH.
After the processor part 16 finishes the process in Step SP 8 , it goes to Step SP 9 . It determines whether the user terminal unit 3 instructs finishing the provision of the zoomed-in video V 2 . Here, when the instruction is not made, the process goes from Step SP 9 to Step SP 6 . On the other hand, when the instruction is made in Step SP 9 , the process goes from Step SP 9 to Step SP 10 to end the process steps.
In contrast to this, when the tracking is unsuccessful in Step SP 6 , the processor part 16 goes from Step SP 6 to Step SP 11 . It in turn scales up the partial area without varying the center position of the partial area set in the current frame, whereby it zooms out the zoomed-in video V 2 , and goes to Step SP 9 . In addition, in this case, the selecting part 12 assures that the resolution of the moving image data SV 2 is not changed even though the partial area is scaled up by interpolation processing.
FIG. 4 shows a block diagram depicting the details of the configuration of the user terminal unit 3 . In the user terminal unit 3 , an interface (I/F) 21 outputs encoded data DV 1 and DV 2 inputted via the home network 4 to decoders 22 and 23 , and notifies various requests RQ outputted from a controller 21 to the host unit 2 .
The decoders 22 and 23 decode the encoded data DV 1 and DV 2 , respectively, and output moving image data SV 1 and SV 2 .
A display part 26 is formed of a liquid crystal display device, for example, and displays video of moving image data outputted from an image processing part 25 .
The image processing part 25 switches the operation controlled by the controller 24 , selectively outputs the moving image data SV 1 and SV 2 , and as shown in FIG. 5A or 5 B, it displays the video slightly zoomed out V 1 or the zoomed-in video V 2 on the full screen on the display part 26 . In addition, as shown in FIG. 5C , when the video slightly zoomed out V 1 is displayed on the full screen, it shows a frame W 1 in the area for cutting out the zoomed-in video V 2 . Moreover, when the controller 24 instructs the display of a picture in a picture, as shown in FIG. 5D , the video slightly zoomed out V 1 is displayed on a sub-screen in the state in which the zoomed-in video V 2 is displayed on the full screen. In addition, in the display of a picture in a picture, the frame frequency of the video slightly zoomed out V 1 from the moving image data SV 1 is increased by a scheme of pre-interpolation, and is set so as to match with the frame frequency of the zoomed-in video V 2 from the moving image data SV 2 , whereby video V 1 and V 2 is displayed.
A remote commander (remote controller) 27 is a remote control device of the user terminal unit 3 , which outputs remote control signals in infrared rays or radio waves.
The controller 24 is a control unit that controls the operation of the user terminal unit 3 in response to the operation of the remote commander 27 by executing a program recorded on a memory, not shown. In addition, in the embodiment, although the program is installed in the user terminal unit 3 in advance and offered, instead of this, the program may be offered by recording it on a recording medium such as an optical disk, a magnetic disk, and a memory card, and the program may be offered by downloading it via network such as the Internet. In addition, the decoders 22 and 23 , and the image processing part 25 may be configured of a functional block of a processor unit configuring the controller 27 .
FIG. 6 shows a flow chart depicting the process steps of the controller 24 . When a user instructs reproducing video contents by operating the remote commander 27 , the controller 24 goes from Step SP 11 to Step SP 12 , and it requests the host unit 2 to supply the list of the video contents. In addition, the controller displays the list of the video contents supplied from the host unit 2 by the request on the display part 26 , and accepts the selection of video contents by the user.
Subsequently, the controller 24 goes to Step SP 13 , it requests the host unit 2 to reproduce the video contents selected by the user, and displays the video contents of encoded data DV 1 outputted from, the host unit 3 on the display part 26 . Thus, the controller 24 starts providing the video contents.
Subsequently, the controller 24 goes to Step SP 14 , and it determines whether the user operates the remote commander 27 to instruct showing zoomed-in video. Here, when it is negative, the controller 24 goes from Step SP 14 to Step SP 21 , and determines whether the user operates the remote commander 27 to instruct finishing the reproduction of the video contents. Here, when it is negative, the controller 24 returns from Step SP 21 to Step SP 14 , whereas when it is positive, the controller instructs the host unit 2 to finish reproducing the video contents, and goes from Step SP 21 to Step SP 22 to end the process steps.
In contrast to this, when it is positive in Step SP 14 , the controller 24 goes from Step SP 14 to Step SP 15 . Here, the controller 24 requests the host unit 2 to output a still image, and displays the still image by switching the operation in the host unit 2 . In addition, it displays a cursor on the still image.
In addition, in the subsequent Step SP 16 , it moves the position of the cursor displayed on the still image in response to the operation of the remote commander 27 , and accepts the setting of the partial area to reproduce zoomed-in video. The controller 24 notifies the coordinate value inputted by accepting the setting to the host unit 2 , and notifies the coordinates of the partial area to reproduce zoomed-in video to the host unit 2 .
Subsequently, the controller 24 goes to Step SP 17 , it instructs the decoder 23 to activate the operation, whereby the encoded data DV 1 and DV 2 sent from the host unit 2 is set to be decoded in the decoders 22 and 23 , respectively. In addition, it instructs the image processing part 25 to display a picture in a picture. In this case, as shown in FIG. 5D , the zoomed-in video V 2 is displayed on the full screen, and the video slightly zoomed out V 1 is displayed on the sub-screen at the left corner.
Subsequently, the controller 24 goes to Step SP 18 , and determines whether the user operates the remote commander 27 to switch display. Here, when it is positive, it goes from Step SP 18 to Step SP 19 , switches the settings of the image processing part 25 to change the display of the display part 26 , and then goes to Step SP 20 . In addition, here, the switching of the display by the display part 26 is the process of repeatedly switching the display in turn in response to the operation by the user, for example, on the full screen display of the zoomed-in video shown in FIG. 5B , the full screen display of the video slightly zoomed out shown in FIG. 5C , and the picture in a picture display shown in FIG. 5D .
In contrast to this, when it is negative in Step SP 18 , the controller 24 directly goes from Step SP 18 to Step SP 20 . In Step SP 20 , the controller 24 determines whether the user instructs finishing the display of the zoomed-in video. Here, when it is positive, it instructs the host unit 2 to stop the output of the zoomed-in video, and then returns to Step SP 14 . In contrast to this, when it is negative in Step SP 20 , the controller returns from Step SP 20 to Step SP 18 .
As described above, in the video content providing system 1 , as shown in FIG. 7 , information that specifies the partial area to generate zoomed-in video is notified from the user terminal unit 3 on the monitor side to the host unit 3 . For the partial area, the moving image data SV 2 is sent in all the pixels and all the frames of the moving image data DVH, and for the other portions, the pixels and the frames are thinned out to send the moving image data SV 1 . In addition, in the embodiment, the moving image data SV 1 to send the video slightly zoomed out is configured to send video for the partial area to generate zoomed-in video as well. However, for example, this scheme may be performed in which encoded data for the partial area is not sent by the settings of control codes in the encoder 13 to further reduce the data volume to send. In addition, in this case, it is necessary to use the moving image data SV 2 on the image processing part 25 to interpolate the image data of the partial area.
As described above, when the area of 1/s of video of the moving image data SVH is partially cut out and is sent by the moving image data SV 2 , suppose the pixel thinning rate and the frame thinning rate are set to m and n, respectively, the transmission volume can be reduced to (1/S+((S−1)/S)×(1/n)×(1/m)) in total more than the case of directly sending the moving image data SVH. Here, more specifically, the transmission volume is 19/64, where s=4, n=4, and m=4, and thus the transmission volume can be reduced to about ⅓.
2. Operation of the Embodiment
In the configuration above, in the video content providing system 1 ( FIGS. 1 and 4 ), the user terminal unit 3 makes a request for reproducing the moving image data SVH and the audio signal of the video contents in the recording/reproducing device 11 of the host unit 2 , and the moving image data SVH and the audio signal are sent to the user terminal unit 3 , whereby the video contents desired by the user can be viewed on the user terminal unit 3 among a large volume of video contents stored in the host unit 2 .
Here, the video contents thus provided from the user terminal unit 3 are sometimes the video contents that a sport relay broadcasting program is recorded, for example. In this case, a user follows a favorite player, for example, and sometimes desires to watch the favorite player zoomed in. In addition, a user sometimes follows and watches a bail zoomed in.
Then, in the video content providing system 1 , when a user operates the remote commander 27 and instructs showing zoomed-in video in the user terminal unit 3 , the video contents in moving images are displayed in a still image, and the area is specified in the still image to accept the area to zoom in. In addition, the area to zoom in is notified to the host unit 2 . In the host unit 2 , the moving image data SV 2 of the specified area is cut out of the moving image data SVH of the video contents to be reproduced in the recording/reproducing device 11 , and the moving image data SV 2 is sent to the user terminal unit 3 together with the moving image data SV 1 . Thus, in the video content providing system 1 , the moving image data for display is switched in the user terminal unit 3 , whereby the zoomed-in video of the desired portion can be displayed on the full screen, or the entire video can be displayed on the full screen, or they can be displayed by a picture in a picture, leading to much more improved convenience for use than the conventional schemes do.
However, when the moving image data SV 2 in the specified area is simply cut out of the moving image data SVH of the video contents to be reproduced in the recording/reproducing device 11 , the data volume to send becomes enormous. Particularly, in order to prevent out-of-focus moving images and jerkiness from occurring in the moving image data SV 2 to be cut out and generated, it is necessary to generate the original moving image data SVH in really high resolution, and to generate it at a high frame rate. Even though the original moving image data DVH is sent, the data volume to send becomes enormous.
For one of schemes of solving the problem, it can be considered that the moving image data SV 2 is cut out on the user terminal unit 3 side, but in this case, in order to prevent out-of-focus moving images and jerkiness from occurring in the cut out video, it is necessary to generate the original moving image data SVH in really high resolution, and to generate it at a high frame rate. Also in this case, the data volume to send becomes enormous.
Then, in this embodiment, the video contents are recorded in the moving image data SVH of high resolution at a high frame rate so that out-of-focus moving images and jerkiness are prevented from occurring in the moving image data SV 2 to be cut out and generated. In addition, for the moving image data SVH of a high frame rate, the pixels and the frames are thinned out to generate the moving image data SV 1 , and the moving image data SV 1 is sent to the user terminal unit 3 .
Thus, in the video content providing system 1 , out-of-focus moving images and jerkiness can be prevented while an increase in the data volume to send is being avoided, and the video slightly zoomed out and zoomed-in video can be selectively provided to a user.
In other words, in the host unit 3 , the subject included in the partial area specified by the user is detected, and the tracking target for zoomed-in video is detected. In addition, the partial area to generate zoomed-in video is moved so that the target for tracking is tracked, whereby the zoomed-in video such as a player desired by the user can be displayed in the user terminal unit 3 . In this embodiment, the detection and tracking of the target for tracking are performed with the use of the video signal SV 1 reduced in the resolution and the frame rate, whereby the configuration of providing the zoomed-in video and the video slightly zoomed out to the user is effectively used, and a desired subject is tracked by a simple process to display zoomed-in video.
In addition, when it is difficult to track the target, the size of the partial area to generate zoomed-in video is scaled up. In this case, although it is difficult to move the picture frame of zoomed-in video so as to track the desired subject, the desired subject can be roughly captured as zoomed-in video. In addition, even though the desired subject is not captured, agreeable video can be displayed. In other words, for example, in the cases in which a ball is followed by a television camera in a baseball game, and a ball is followed by a television camera in an American football game, it is sometimes difficult for even a fine camera person to follow the motion of the ball. In this case, when a camera person does not follow the bail, he/she temporarily zooms out, and again takes the target for tracking in the picture frame to zoom in the target for tracking. Therefore, in the case in which it is difficult to follow the target, the size of the partial area to generate zoomed-in video is scaled up, and then the operations of the camera person like this can be reproduced to display agreeable zoomed-in video.
3. Advantages of the Embodiment
According to the configuration above, the moving image data of high resolution at a high frame rate is partially cut out to generate the zoomed-in moving image data as well as the resolution and the frame of the remaining portion are thinned out to generate the moving image data slightly zoomed out, and the zoomed-in moving image data and the moving image data slightly zoomed out are sent, whereby out-of-focus moving images and jerkiness can be prevented while an increase in the data volume to send is being avoided, and the video slightly zoomed out and zoomed-in video can be selectively provided to a user.
In addition, the motion or the subject included in the partial area to generate the zoomed-in moving image data is tracked, and the partial area is moved as it follows the motion of the subject, whereby zoomed-in video can be displayed so as to track the desired subject.
In addition, the video slightly zoomed out is displayed on the user terminal unit 3 on the display device side, and the display device accepts the setting of the partial area to generate zoomed-in video, whereby the zoomed-in video of the subject desired by a user can be displayed.
In addition, more specifically, since the moving image data of the video contents that is the original of zoomed-in video is the video signal of a frame frequency of 120 Hz or greater, it is ensured that out-of-focus moving images and jerkiness can be prevented.
Embodiment 2
FIG. 8 snows a block diagram depicting a video content providing system according to Embodiment 2 of the invention. In this video content providing system 31 , a television camera 33 shoots the moving image data DVH of high resolution at a high frame rate, and the video contents of the moving image data DVH are provided to a user terminal unit 36 over a communication network 35 . In addition, here, for the communication network 35 , such networks are adapted including the Internet and a broadcast network that can make interactive data communications with the reception side.
Here, as similar to the host unit 2 according to Embodiment 1, the host unit 32 generates zoomed-in moving image data from moving image data SVH taken by the television camera 33 according to a request from the user terminal unit 36 , and sends the data to the user terminal unit 36 together with the moving image data slightly zoomed out. Here, in this embodiment, since the moving image data SVH of the television camera 33 obtained in real time is the original to generate the zoomed-in moving image data, the host unit 32 analyzes the moving image data slightly zoomed out all the time, and tracks the motions of individual subjects in the moving image data slightly zoomed out. In addition, based on the results of tracking the motions, the host unit records and holds position information of the individual subjects together with the time code of the moving image data slightly zoomed out.
In addition, the user terminal unit 36 displays video of the moving image data slightly zoomed out, and when the user instructs showing zoomed-in video, it displays the video slightly zoomed out having been displayed in a still image, and accepts the selection of a target for tracking in zoomed-in video on the still image. The user terminal unit 36 notifies the time code of the video displayed on the still image and the coordinate value of the target subject for tracking to the host unit 32 .
The host unit 32 searches the position information of the individual subjects recorded and held with the notified time code and the coordinate value, and detects the coordinates of the target for tracking in the current frame from the searched result. In addition, it in turn computes the partial area to generate zoomed-in video from the detected coordinates, selects the moving image data DVH based on the computed result, and outputs the zoomed-in moving image data. The video content providing system is similarly configured as the video content-providing system 1 according to Embodiment 1 except that the scheme of setting the partial area to cut out the zoomed-in video is different.
According to the embodiment, even though the video contents are made of real time moving image data, the same advantages as those of Embodiment 1 can be exerted.
Embodiment 3
In addition, in the embodiments above, the case is described in which a still image is displayed to accept settings of the tracking target in zoomed-in video. However, an embodiment of the invention is not limited thereto. Such a scheme may be performed in which when it is assured that the tracking target can be reliably inputted in practice, the settings of the tracking target are accepted in the state in which moving images are displayed.
In addition, in the embodiments above, the case is described in which the moving image data slightly zoomed out is sent including the partial area to cut out zoomed-in video, and the zoomed-in moving image data and the moving image data slightly zoomed out are encoded for transmission. However, an embodiment of the invention is not limited thereto. Such a scheme may be performed in which the moving image data slightly zoomed out is send only for the area except the partial area to cut out zoomed-in video, and the zoomed-in moving image data and the moving image data slightly zoomed out are collectively encoded.
In addition, in the embodiments above, the case is described in which pixels and frames are thinned out at certain thinning rates. However, an embodiment of the invention is not limited thereto. For example, the thinning rate may be dynamically varied in accordance with the usable transmission bands. In addition, in the case in which any one of zoomed-in video and video slightly zoomed out is selectively viewed on the user terminal unit side, for the video on the unviewed side, the output of moving image data may be stopped.
For example, an embodiment of the invention can be adapted in the case in which video contents such as a sport program are provided for a user.
It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof. | A content providing method, a program of a content providing method, a recording medium on which a program of a content providing method is recorded, and a content providing apparatus are provided. The content providing method includes the steps of: outputting moving image data of video contents; selecting moving image data in a partial area from the moving image data of the video contents, and outputting zoomed-in moving image data; thinning out frames and pixels of the moving image data of the video contents except at least the partial area, and outputting moving image data slightly zoomed out; and outputting the zoomed-in moving image data and the moving image data slightly zoomed out. | 7 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation-in-part of U.S. application Ser. No. 29/456,624, filed May 31, 2013, the contents of which are incorporated by reference.
FIELD OF THE INVENTION
[0002] The invention relates to management and use of solar power for golf cars at a golf course.
BACKGROUND
[0003] Golfers dislike being stranded by a golf car that stops working unexpectedly. This causes employees of the facility (who are typically busy doing other things) to have to find a fully charged car and tow it out with another charged car to the place where the customers are abandoned. Pace of play on the golf course is stopped during this process backing up golfers for many holes. Then all the items in the dead car are needed to be transferred to the charged car (if the course even has one available) and the dead car is towed back the charging barn. Since golf courses are businesses that will not succeed if they create misery for their customers, they will not adopt golf cars that cease to work out on the course. This reluctance is in tension with increasing consumer demand for environmentally friendly products and services that do not burn through fossil fuels and pollute the air.
[0004] U.S. Pub. 2011/0210693 to Reichart reports a method of powering a golf car with solar energy and claims to provide 9 hours of power to a golf car. Unfortunately, this method only provides 200 watts and requires unstated assumptions to be true—that there will be no other drain on the power supply, that the golf course is of typical size with no remarkable hills or other features that would tax the motor, and that management will carefully log charging times and always provide every golfer with a fully charged car.
[0005] U.S. Pub. 2013/0335002 to Moore and U.S. Pat. No. 5,725,062 to Fronek report solar vehicles but neither makes any provision for ensuring adequate power to play 18 holes. Golf courses may not adopt the reported vehicles and methods since their circumstances may cause those vehicles to run out of power and stop working unexpectedly, leaving unhappy golfers, far from the parking lot and club house, stranded in the sun their heavy golf bags with until a fresh cart arrives, at a tremendous cost to the facility.
SUMMARY
[0006] The invention provides an electrical vehicle power system that compares power use to anticipated need and regulates power use so that the anticipated need is satisfied by available power, thus ensuring ample power for a user to complete an activity such as playing a round of golf. The system uses a controller coupled to a photovoltaic cell on a golf car in a lightweight and durable solar roof apparatus that can retrofit to existing carts. The golf car is provided for use at a specific golf course and the controller uses information about power demands unique to that golf course to regulate power to the motor to ensure that the golf car completes a round of golf. Since the system is frugal with electricity only when it needs to be—e.g., on cloudy days or at golf courses with many steep hills to climb—the golf car can make surplus electricity available at times, which can be used for powering personal electronic devices or even can be fed back into the grid. The invention may include infrastructure installed at a golf course to manage electricity for numerous golf cars. Since each cart has a photovoltaic cell and a power controller that can use a power demand map unique to that golf course, the carts will not strand golfers out on the course and will even supply surplus power back into the system when available. Furthermore, through use of the solar roof apparatus, a golf course can retrofit their fleet of carts to minimize their energy costs and even sell power back to the utility commission without having to purchase an entire new fleet. This additionally allows the facility to purchase more cars to service customers. Thus systems and methods of the invention may provide considerable savings to a golf course in energy bills and will provide golfers with reliable carts that do not leave them stranded. Moreover, consumer sensitivity to environmental considerations is a driver of loyalty. Since a golf course will save on its energy bills while also retaining and growing a base of satisfied customers, systems and methods of the invention provide significant long-term improvements to the bottom line for a golf course.
[0007] In certain aspects, the invention provides a golf car power system that includes a golf car made available for use at a golf course, a photovoltaic cell mounted on the golf car (preferably integrated into the roof the car), and a controller system. The controller system includes a power management device electrically coupled to the cell and a processor coupled to a non-transitory memory and optionally having stored therein information about power required for the golf car to operate for a duration of a round of golf at the golf course.
[0008] Preferably the controller system is operable to compare present power use to the information about the power required and regulate the motor so that an amount of power remaining is at least as great as an anticipated amount of power required to complete the round of golf. The power management device may include a maximum power point tracking device, and regulating the motor can be done by limiting a maximum speed of the golf car.
[0009] The information about the power required can use an average distance travelled per typical round of golf. Present power use may be determined by tracking cumulative distance traveled in the round of golf at the golf course. The connection with the external power system can provide power from the external system to the golf car and provide power from the golf car to the external system.
[0010] In some embodiments, the controller system has a communication device operable to exchange data about the power system with a system management server computer. The system can include an “electricity gas gauge”—a display visible to a driver of the golf car that shows an amount of power remaining. The system may include a positioning device (e.g., a GPS device or barcodes and readers on the course) on the golf car to provide information to the controller system showing a present location of the golf car. The system may include the locationing system described in U.S. Pub. 2004/0243262 to Hofmann, the contents of which are incorporated by reference.
[0011] In a preferred embodiment, the information about the power required stored in the controller system includes a digital map of the golf course. The cart includes, in computer memory, a map. Map can mean a digital representation of a spatial layout of the course, or it can mean a recorded plan of distances to be traveled optionally with heights to be ascended along golf car paths during a round of golf for that course (e.g., an elevation change map for the golf car route for that course). The system can include maps for different courses, with the appropriate map being called into use at any given course. Thus, in certain embodiments, the controller system has stored therein a plurality of maps of different golf courses that includes a map that represents the golf course, wherein the information about the power required indicates which map represents the golf course.
[0012] The power system may include a power jack on the golf car for providing power to a personal electronic device. Thus a golfer may charge their smartphone or use their tablet computer in the cart. Additionally or alternatively, the system may include a connection point for making a connection with an external power system.
[0013] Aspects of the invention include a power management method for a golf car. Power for a golf car is obtained during a round of golf at a predetermined golf course through the use of a photovoltaic power system on the golf car. The method includes tracking a distance driven by the golf car during the round of golf, comparing the tracked distance to an average total distance associated with the predetermined golf course using the power system on the golf car; and regulating power consumption of the golf car, using the power system, so that the golf car will not run out of power until it has driven the average total distance. Preferably, the power system comprises one or more of a photovoltaic cell, a battery, a motor, a maximum point power tracking device, a processor, and a non-tangible computer-readable storage medium having stored therein information about the predetermined golf course. Surplus power may be provided from the golf car to a local grid at the predetermined golf course. The method includes displaying an amount of power remaining to a driver of the golf car via a display gauge.
[0014] In certain aspects, the invention provides a power management system for a golf course. The system includes a local electrical grid system installed at a golf course, which local grid has at least one connection to an external municipal power system, at least one battery system, and at least one charging station. The system includes golf cars that each have a photovoltaic cell and a jack connectable to the charging station. A system management server computer monitors power consumption in the golf cars. Each golf car captures power via its photovoltaic cell, provides surplus power to the at least one power system such as a battery or other storage device at a time when it is connected to the charging station and fully charged, and draws power from the at least battery system at a time when it is connected to the charging station and not fully charged. In some embodiments, each golf car has a controller system that includes a power management device electrically coupled to the cell; a processor; and a memory device having stored therein information unique to the golf course. The controller system uses the information unique to the golf course to regulate power use so that the golf car is operable for a duration of a round of golf on the golf course. The local electrical grid system may be operable to provide surplus local grid power to the external municipal power system with the server computer providing a statement of an amount of surplus local grid power provided to the external municipal power system.
[0015] Within the system, preferably each golf car includes a controller system with a power management device, a computer having stored therein information unique to the golf course, and a display showing power remaining The controller system uses the information unique to the golf course and the power remaining to modulate power consumption.
[0016] Other aspects of the invention provide a solar apparatus for a golf car. The apparatus is a solar roof installable onto a golf car. It includes a roof member with support legs for connection to a golf car, a photovoltaic cell at a top surface of the roof member, and a connection jack to electrically connect the photovoltaic cell to an electrical system of the golf car. The solar apparatus may include other features such as rain gutters to direct rain away from the photovoltaic cell and occupants of the golf car. In some embodiments, the support legs are configured to mate to pre-determined mounting points of a specified model of golf car. The apparatus may have a built-in maximum power point tracking device installed within the apparatus between the photovoltaic cell and the connection jack. The apparatus can include an “electricity gas gauge”—a gauge disposed on the apparatus and configured to be visible to a driver of the golf car when the apparatus is installed on the golf car. The gauge displays information about electrical power available to the golf car.
[0017] In certain embodiments, the apparatus will include a meter device configured to measure a distance that the golf car has been driven. Other possible features include a USB port to provide electricity to a device when the device is plugged into the USB port, an external jack for making a connection to a charging station (to provide and receive electrical power through the connection), or both. The apparatus may include a processing unit having stored therein information unique to at least one predetermined golf course and operable to limit output of a motor on the cart if the cart's usage at full speed will exceed an available amount of energy.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 depicts a golf car power system.
[0019] FIG. 2 depicts a roof member for a solar golf car.
[0020] FIG. 3 is a cross section along a roof member.
[0021] FIG. 4 is a cross section across a roof member.
[0022] FIG. 5 is a diagram of components of a controller system.
[0023] FIG. 6 diagrams a method for managing power of a golf car.
[0024] FIG. 7 depicts a map of a predetermined golf course.
[0025] FIG. 8 shows a power management system for a golf course.
[0026] FIG. 9 shows a device for displaying an amount of power remaining
[0027] FIG. 10 illustrates a method of managing power at a golf course.
[0028] FIG. 11 illustrates an interface to a golf course power management system.
[0029] FIG. 12 shows a photovoltaic roof assembly of the invention on a golf car according to certain embodiments.
DETAILED DESCRIPTION
[0030] FIG. 1 depicts a golf car power system 101 . System 101 includes a golf car 131 made available for use at a golf course, a photovoltaic cell 109 mounted on a roof member 113 of the golf car supported by uprights 121 , a motor 129 to drive golf car 131 , and a controller system 501 . Controller system 501 includes a power management device electrically coupled to the cell 109 . Roof member 113 with cell 109 defines a solar apparatus 139 for golf car that may be provided as a standalone apparatus 139 (optionally with or without support uprights 121 connected via support bosses 117 ). Apparatus 139 is a solar roof installable onto golf car 131 .
[0031] FIG. 2 depicts a roof member 113 for a solar golf car. A photovoltaic roof assembly includes a roof member 113 mountable to an electric vehicle, and a photovoltaic assembly including a PV cell 109 at the upper part of the roof. The photovoltaic assembly may be mounted to a separate roof surface or the photovoltaic assembly may itself constitute all or part of the roof. As shown in FIG. 2 , the roof apparatus may include gutters 213 . The roof may have mounting element recesses to accommodate mounting elements of the photovoltaic assembly, the mounting elements configured so as not to shade the photovoltaic panel. The roof may also be configured to accommodate a global positioning device. The roof preferably includes a peripheral gutter 213 . The roof body preferably includes handhold recesses housing handhold elements 305 at positions to provide a horizontal setback from the lateral sides of the roof body. Roof member 113 connects to a golf car via support legs 121 (shown in FIG. 1 ). Additional discussion of photovoltaic cells suitable for modification for use with the invention may be found in U.S. Pat. No. 5,725,062 to Fronek and U.S. Pat. No. 6,702,370 to Shugar, the contents of each of which are incorporated by reference for all purposes.
[0032] The roof assembly may be mounted on top of upright supports 121 that attach to an electric vehicle. The upright supports 121 will have mounting points on the bottom attaching it to the 3 most common type of electric vehicles (Club Car, Yamaha, EZ-Go) but may also be customized to fit others. The front upright supports will be angled in a way that will slant towards the interior of the cart allowing rain to fall away from the passengers and lower the reflection of the sun. The uprights will house any wires that run from solar panel or controller down to the batteries keeping it housed and away from elements. The stylization of the roof system begins where the uprights connect to the cart itself. The windshield becomes part of the stylized element and organically blends into the roof creating a natural ergonomic curve shape.
[0033] The vertical uprights 121 may emerge from the cart at the designed locations for the most popular makes of golf cars. The uprights 121 transform into a stylized element that is part of the roof system. In doing this, the roof system including the uprights 121 will be able to maintain its distinct style even if the golf car manufacturer changes its mounting scheme on the cart. The benefit a golf course manager is that it won't be necessary to change any aspects of the roof itself should the mounting points of the uprights of the cart manufacturer change. A photovoltaic cell 109 on is disposed on a top surface of roof member 201 .
[0034] FIG. 3 is a cross section of roof member 113 along line 3 - 3 ′ in FIG. 2 . Roof member 113 includes bosses 117 to connect to support legs 121 to provide a lightweight solar roof with benefits that include a reduction in the amount of “grid charging” required to maintain a charge in the batteries for operation. The reduction in electricity costs benefit the bottom line of a golf course. Environmental impact of the golf course utilizing these systems is greatly reduced. Benefits include less strain on the energy grid, reduced air pollution, reduced water pollution, reduction in landfill disposal of toxic batteries.
[0035] FIG. 4 is a cross section of roof member 113 along line 4 - 4 ′ in FIG. 2 . The solar apparatus may include other features such as rain gutters 213 to direct rain away from the photovoltaic cell 109 and occupants of the golf car. In some embodiments, the support legs 121 are configured to mate to pre-determined mounting points of a specified model of golf car.
[0036] FIG. 5 is a diagram of components of controller system 501 . Controller system 501 includes cell 109 and preferably includes one or more of a maximum power point tracking (MPPT) device 505 , a motor 129 , a cart battery 537 , a power connection 539 , a data connection 561 , a positioning device 565 , an electronic device 571 , a display device 579 , or any combination thereof. Plug 591 is an optional connection between electrical components on a detachable roof apparatus and electrical components on a golf car (e.g., motor 129 and battery 537 ). Power connection 539 allows the cart to plug into a charging station. Data connection 561 may be a USB jack. A sensor 573 can track revolutions of the wheels or function as an odometer.
[0037] System 501 preferably includes an MPPT device 505 . The MPPT device 505 is used for its ability to capture changing voltage outputs from the solar panel 109 . The nature of an electric golf vehicle dictates that it be used outdoors. By accepting current in low light conditions, shade, direct light conditions, fog etc. the MPPT device 505 may allow the owner of the vehicle to avoid charging the vehicle as much as a non-solar electric vehicle or a solar electric vehicle that doesn't use an MPPT device 505 . The use of an MPPT device 505 may also allow the driver of the electric vehicle to avoid running out of charge while in use. The benefit is less customer anguish, lowering of labor costs in running a freshly charged cart out on the course and safety issues involved in having stranded golfers in the way of golf balls from behind.
[0038] The MPPT device 505 may be wired directly into roof member 113 and wires may extend laterally along the underside of the roof in a housed compartment and into the body of the vehicle and ultimately into the battery compartment. The benefit to this feature is the wiring harness is housed inside the upright 121 of the cart 101 , which protects the wiring from weather and the possibility of being bumped when people are reaching for items in the cart or golf clubs.
[0039] MPPT device 505 may be installed within the apparatus between the photovoltaic cell 109 and the jack that connects the solar roof apparatus to the golf car. The apparatus can include for display 579 an “electricity gas gauge”—a gauge disposed on the apparatus and configured to be visible to a driver of the golf car when the apparatus is installed on the golf car. The gauge display 579 displays information about electrical power available to the golf car. Additionally helpful discussion may be found in U.S. Pub. 2011/0210693 to Reichart; U.S. Pub. 2008/0143292 to Ward; and U.S. Pub. 2013/0335002 to Moore, the contents of each of which are incorporated by reference for all purposes.
[0040] In certain embodiments, the apparatus will include a meter device (e.g., GPS device 565 or an odometer or a revolution counter) configured to measure a distance that the golf car has been driven. Other possible features include a USB port 561 to provide electricity to a device when the device is plugged into the USB port, an external jack 539 for making a connection to a charging station (to provide and receive electrical power through the connection), or both. The apparatus may include a processing unit 571 having stored therein information unique to at least one predetermined golf course and operable to limit output of motor 129 on the cart if the cart's usage at full speed will exceed an available amount of energy.
[0041] MPPT device 505 is a microcontroller based electronic device for charging the energy storage module (e.g. batteries) of a golf car from the roof mounted photovoltaic solar array. The device has features to maximize the utilization of the solar array, provide a “gas gauge” display of available energy, store a history of events and usage, and has a unique feature that interacts with the cart's motor controller to modulate the amount of power available to the cart driver to insure that enough energy is available to complete a round of golf.
[0042] The golf car has battery 537 typically made up of a number of batteries. These batteries are typically lead-acid chemistry, but could also be another battery chemistry or some other form of energy storage, all will be referred to as “battery”. The battery is to be charged via the solar array 109 and maximum power point tracking (MPPT) methods and devices are used to control power use. Specifically, a typical MPPT device 505 will include a DC to DC converter that matches output of panel 109 to load. The microcontroller has several algorithms that can be tailored for the type of battery and solar array to provide the most efficient use of the solar energy.
[0043] The device 505 monitors the energy flowing into the battery 537 and out to the motor 129 . The capacity and characteristics of the battery 537 are known to the controller 505 and therefore a very accurate estimation can be made of the available energy. An analogy is the gas gauge on an automobile. The computation of available energy is a complex interaction of not only power in (from the solar array), power out (to the motor), but of the rate of energy use i.e. in most battery systems, the apparent amount of stored energy becomes smaller as the rate of consumption becomes higher. In lead-acid chemistry, for example, this relationship is defined by Peukert's Law. The microcontroller 505 is able to sample voltages and currents many times a second and calculate a complex formula and display on display 579 the results to the cart driver instantaneously. Further discussion of MPPT devices may be found in U.S. Pub. 2009/0160258 to Allen; U.S. Pub. 2011/0297459 to Hayek; U.S. Pub. 2014/0097669 to Nagashima; U.S. Pub. 2011/0163710 to Syed; U.S. Pub. 2011/0162897 to Syed; and U.S. Pat. No. 8,419,118 to Petersen, the contents of each of which are incorporated by reference.
[0044] The device stores a history of events and usage (e.g., either within MPPT device 505 , computer 571 , or both). This data is useful to the owners of the golf cars to understand such things as energy savings provided by the solar array, operations potentially damaging to the battery 537 , usage in relation to required servicing, and operational information that can be used to fine tune and improve the operation of the cart in the future. The device uses some of this information internally to improve its MPPT algorithm and “gas gauge” function. System 501 can be programmed using ‘fuzzy logic’ algorithms known in the art so that the microcontroller based device can change its own programming to suit present conditions or ‘remember’ conditions and usage. Other information can be output to the cart's operator in the form of data that can be used for reporting and review.
[0045] The typical golf car is used on a fixed course whose size is known. The golf car traverses typically 18 holes of golf and the average distance traveled by the cart is known. A sensor 573 tracks the revolutions of the cart's wheels (alternately distance over ground may be computed from global position system (GPS) information) and the device is able to determine the distance traveled. At any given time there is a certain amount of stored energy available in the battery. The device computes the amount of distance required to complete the round of golf.
[0046] If the cart's usage at full speed will exceed the available amount of energy available, the device will limit the output of the cart's motor to be able to safely cover the distance needed for completion. The calculation is updated frequently to account for varying conditions. For example, a cart in full sunshine would provide maximum charge to battery 537 allowing robust operation of car 131 . Should car 131 be under tree shade, or perhaps a cloudy day, the device will modulate the motor power to extend the range of the cart to allow completion of the round of golf. This will prevent golfers from becoming stranded on the course. The on-cart system may include a USB charging point.
[0047] Benefits to golfers using golf car 131 with the solar electric charging system include: a reduction in the possibility of the vehicle “dying” during operation. This benefit includes a faster pace of play, avoiding the frustration of having to switch carts (to a cart with fresh batteries) in the middle of a round and avoiding the safety hazard of becoming stranded on a golf course while other golfers are trying to play through.
[0048] Preferably the controller system is operable to compare present power use to the information about the power required and regulate the motor so that an amount of power remaining is at least as great as an anticipated amount of power required to complete the round of golf. The power management device may include a maximum power point tracking device, and regulating the motor can be done by limiting a maximum speed of the golf car.
[0049] The information about the power required can use an average distance travelled per typical round of golf. Present power use may be determined by tracking cumulative distance traveled in the round of golf at the golf course. The connection 539 with the external power system can provide power from the external system to the golf car and provide power from the golf car to the external system.
[0050] In some embodiments, the controller system has a communication device 561 operable to exchange data about the power system with a system management server computer. The system can include an “electricity gas gauge” 579 —a display visible to a driver of the golf car that shows an amount of power remaining. The system may include a positioning device 565 (e.g., a GPS device or barcodes and readers on the course) on golf car 131 to provide information to the controller system showing a present location of the golf car.
[0051] In a preferred embodiment, the information about the power required stored in the controller system includes a digital map of the golf course. Golf car 131 includes, in computer memory, a map. Map can mean a digital representation of a spatial layout of the course, or it can mean a recorded plan of distances to be traveled optionally with heights to be ascended along golf car paths during a round of golf for that course (e.g., an elevation change map for the golf car route for that course). The system can include maps for different courses, with the appropriate map being called into use at any given course. Thus, in certain embodiments, the controller system has stored therein a plurality of maps of different golf courses that includes a map that represents the golf course, wherein the information about the power required indicates which map represents the golf course.
[0052] The power system may include a jack 561 (such as a USB port) on golf car 131 for providing power to a personal electronic device. Thus a golfer may charge their smartphone or use their tablet computer in the cart. Additionally or alternatively, the system may include a connection point 539 for making a connection with an external power system.
[0053] FIG. 6 diagrams a method 601 for managing power of a golf car 131 . Power for a golf car is obtained during a round of golf at a predetermined golf course through the use of a photovoltaic power system on the golf car. The method includes tracking a distance driven by golf car 131 during the round of golf, comparing the tracked distance to an average total distance associated with the predetermined golf course using the power system on golf car 131 ; and regulating power consumption of the golf car, using the power system, so that the golf car will not run out of power until it has driven the average total distance. Preferably, the power system comprises one or more of a photovoltaic cell, a battery, a motor, a maximum point power tracking device, a processor, and a non-tangible computer-readable storage medium having stored therein information about the predetermined golf course.
[0054] FIG. 7 depicts map 701 giving information about a predetermined golf course. While shown in FIG. 7 as a familiar, human-readable plan view map, map 701 may include GPS data points for a golf course, or a schedule of typical power consumption over time or space. An important feature of map 701 is that it is customized to a golf course and thus provides information unique to that golf course about power demands associated with that course. For instance, a golf course with steep hills can have a map 701 that tells system 501 that car 131 will use increased amounts of power at those hills.
[0055] FIG. 8 shows a power management system 801 for a golf course. System 801 includes a local electrical grid system 801 installed at a golf course, which local grid has at least one connection to an external municipal power system 819 , at least one battery system 827 , and at least one charging station 839 . System 801 includes golf cars 131 that each have a photovoltaic cell 109 and a jack 539 connectable to the charging station 839 . Local grid 807 is controlled by controller 813 connected to charging station 839 , battery 827 , and also to an optional system management server computer 833 . Server 833 can be accessed via computer 845 preferably installed at the golf course where local grid 807 is located. Computer 845 may communicate with server 833 via network 857 . A system 801 of the invention includes infrastructure that is installed at a specific golf course. The installed infrastructure includes the local electrical grid 807 , with its charging station 839 and battery 827 . The local infrastructure also includes at least one computer 845 for interacting with system 801 . Server 833 and components of network 857 need not be on-site and may be leased or paid for as a service. Discussion may be found in U.S. Pub 2009/0152947 to Wang; U.S. Pub. 2011/0031171 to Henig; U.S. Pat. No. 6,313,394 to Shugar and U.S. Pub. 2006/0127183 to Bishop, the contents of each of which are incorporated by reference.
[0056] Within system 801 , preferably each golf car 131 includes a controller system 501 with a power management device, a computer having stored therein a map 701 describing the golf course, and a display showing power remaining. Noting again that map 701 need not be the familiar plan view drawing of a location and can instead refer to a schedule of typical power consumption, it is an important feature of system 801 that a golf car 131 includes a map 701 with information about the unique power demands of the golf course where local grid 807 is installed. The interaction of elements described herein is what allows a golf car 131 to be used on a golf course and to refer to map 701 to determine an anticipated power demand for that golf course and to display on display 579 an amount of power remaining or an amount of distance remaining, thus providing golf car 131 with an electricity gas gauge as well as a regulatory mechanism via MPPT device 505 to ensure that car 131 does not cease operation during a round of golf.
[0057] FIG. 9 shows one method and display device 579 for displaying an amount of power remaining Display device 579 communicates with control system 501 (e.g., via a wireless or a wired connection) on car 131 . Controller system 501 uses the information unique to the golf course such as a map 701 and the power remaining to modulate power consumption. Each golf car 131 captures power via its photovoltaic cell, provides surplus power to the at least one battery system at a time when it is connected to the charging station and fully charged, and draws power from the at least battery system at a time when it is connected to the charging station and not fully charged. System 501 on car 131 communicates with system 801 for overall efficient power administration at the golf course. Specifically, system 801 can be administered from system management server computer 833 . System management server computer 833 monitors power consumption in the golf cars 131 .
[0058] FIG. 10 illustrates a system administrator managing power at a golf course through the use of system 801 . A system administrator uses terminal 845 to connect to server 833 via network 857 . Terminal 845 presents a system management dashboard on interface 1025 .
[0059] FIG. 11 illustrates interface 1025 for managing system 801 . As discussed above, each golf car 101 has a controller system 501 that includes a power management device 505 electrically coupled to the cell 109 ; a processor; and a memory device having stored therein information unique to the golf course. The controller system 501 uses the information unique to the golf course to regulate power use so that the golf car 131 is operable for a duration of a round of golf on the golf course. The local electrical grid system 819 may be operable to provide surplus local grid 807 power to the external municipal power system 819 with the server computer 833 providing a statement of an amount of surplus local grid power provided to the external municipal power system 819 .
[0060] Golf facilities utilizing these systems will experience a modern new look for their existing golf cars. This upgrade will help customers feel as if they are riding in a new modern vehicle without the cost of the facility having to replace the actual fleet of vehicles. Facilities can just replace their existing roof and uprights with the Solar roof system and enjoy a new fresh look and feel. With a modernized fleet of golf cars a golf facility is may attract more new and repeat customers, increasing revenue.
[0061] Sustainable energy is provided by a system 801 . Over the past few years, corporate sustainability has become a priority issue for businesses of almost every kind and size. Corporate America now faces a wide range of sustainability-focused inquiries, demands, risks and challenges from customers, investors, regulators, consumers, NGOs and other watchdog groups, and even the media. The golf and hospitality industries are no exception—not only do they face tremendous pressure to cut costs due to the economic downturn (and resulting falling revenues) over the past several years but, to keep up with their competitors in the race to “go green,” they also must develop and implement meaningful sustainability plans. Solar-powered golf cars are a great way to help meet these challenges.
[0062] As shown in FIG. 5 , golf car 131 may include a control system 501 with a computer 571 . As shown in FIG. 8 , system 801 includes a server 833 , a PC 845 , or both. Additionally, controller 813 may optionally include a dedicated computer. MPPT 505 may include elements characteristic of a computer. Further, in some embodiments, display 579 is provided by a mobile electronic device such as a smartphone or tablet which may itself be a computer.
[0063] A computer according to the invention will generally include one or more processors and memory as well as an input/output mechanism (I/O). Where methods of the invention employ a connected computer devices, steps of methods of the invention may be performed using multiple computing devices working together as a system. For example, server 833 , which includes one or more of processors and memory, may obtain data, instructions, etc., or provide results via an interface module or provide results as a file. The server 833 may be engaged over the network 857 by the computer 845 or the display 579 , or the server 333 may be directly connected to the computer 845 , which can include one or more processors and memory, as well as an input/output mechanism.
[0064] In systems of the invention, each computer preferably includes at least one processor coupled to a memory and at least one input/output (I/O) mechanism.
[0065] A processor will generally include a chip, such as a single core or multi-core chip, to provide a central processing unit (CPU). A processer may be provided by a chip from Intel or AMD.
[0066] Memory can include one or more machine-readable devices on which is stored one or more sets of instructions (e.g., software) which, when executed by the processor(s) of any one of the disclosed computers can accomplish some or all of the methodologies or functions described herein. The software may also reside, completely or at least partially, within the main memory and/or within the processor during execution thereof by the computer system. Preferably, each computer includes a non-transitory memory such as a solid-state drive, flash drive, disk drive, hard drive, etc. While the machine-readable devices can in an exemplary embodiment be a single medium, the term “machine-readable device” should be taken to include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) that store the one or more sets of instructions and/or data. These terms shall also be taken to include any medium or media that are capable of storing, encoding, or holding a set of instructions for execution by the machine and that cause the machine to perform any one or more of the methodologies of the present invention. These terms shall accordingly be taken to include, but not be limited to one or more solid-state memories (e.g., subscriber identity module (SIM) card, secure digital card (SD card), micro SD card, or solid-state drive (SSD)), optical and magnetic media, and/or any other tangible storage medium or media.
[0067] A computer of the invention will generally include one or more I/O device such as, for example, one or more of a video display unit (e.g., a liquid crystal display (LCD) or a cathode ray tube (CRT)), an alphanumeric input device (e.g., a keyboard), a cursor control device (e.g., a mouse), a disk drive unit, a signal generation device (e.g., a speaker), a touchscreen, an accelerometer, a microphone, a cellular radio frequency antenna, and a network interface device, which can be, for example, a network interface card (NIC), Wi-Fi card, or cellular modem.
[0068] Any of the software can be physically located at various positions, including being distributed such that portions of the functions are implemented at different physical locations.
[0069] Systems of the invention may be used to perform methods described herein. Instructions for any method step may be stored in memory and a processor may execute those instructions.
[0070] FIG. 12 depicts a golf car 131 with a solar roof apparatus 1213 according to a preferred embodiment. Golf car 131 is made available for use at a golf course with a photovoltaic cell 109 mounted on a roof member 1213 of the golf car supported by uprights 1221 . Roof member 1213 with cell 109 defines a solar apparatus 1239 provided as a standalone apparatus 1239 (optionally with or without support uprights 1221 connected via support bosses). Apparatus 1239 is a solar roof installable onto golf car 131 and may include gutters 2213 .
[0071] The roof may have mounting element recesses to accommodate mounting elements of the photovoltaic assembly, the mounting elements configured so as not to shade the photovoltaic panel. The roof may also be configured to accommodate a global positioning device. The roof preferably includes a peripheral gutter 2213 . The roof body preferably includes handhold recesses housing handhold elements at positions to provide a horizontal setback from the lateral sides of the roof body.
[0072] Roof member 1213 connects to a golf car via support legs 1221 . Additional discussion of photovoltaic cells suitable for modification for use with the invention may be found in U.S. Pat. No. 5,725,062 to Fronek and U.S. Pat. No. 6,702,370 to Shugar, the contents of each of which are incorporated by reference for all purposes.
[0073] A photovoltaic (PV) roof assembly 1239 includes a roof mountable to an electric vehicle, and a PV assembly 109 at the upper part of the roof. The PV assembly 109 may be mounted to a separate roof surface or the PV assembly may itself constitute all or part of the roof. The roof 1239 may have mounting element recesses to accommodate mounting elements of the PV assembly, the mounting elements configured so as not to shade the PV panel. The roof may also be configured to accommodate a global positioning device. The roof preferably includes a peripheral gutter 213 . The roof body 1213 preferably includes hand-hold recesses housing hand-hold elements at positions to provide a horizontal setback from the lateral sides of the roof body.
[0074] The roof assembly 1239 may be mounted on top of upright supports 1221 which attach to an electric vehicle 131 . The upright supports 1221 will have mounting points on the bottom attaching it to common type of electric vehicles (Club Car, Yamaha, EZ-Go) but may also be customized to fit others. Roof assembly 1239 may include gutter(s) 213 . The front upright supports 1221 will be angled in a way that will slant towards the interior of the cart allowing rain to fall away from the passengers and lower the reflection of the sun as shown in FIG. 12 . The uprights will house any wires that run from solar panel or controller down to the batteries keeping it housed and away from elements. An MPPT controller 505 is used for its ability to capture changing voltage outputs from the solar panel 109 . The nature of an electric golf vehicle 131 dictates that it be used outdoors. By accepting current in varying light conditions such as a shade, fog, and direct sunlight, the MPPT controller may allow the owner of the vehicle to avoid charging the vehicle as much as a non-solar electric vehicle or a solar electric vehicle that doesn't use an MPPT controller. The use of an MPPT controller may also allow the driver of the electric vehicle to avoid running out of charge while in use. The benefit is less customer anguish, lowering of labor costs in running a freshly charged cart out on the course and safety issues involved in having stranded golfers in the way of golf balls from behind.
[0075] The stylization of the roof system begins where the uprights 1221 connect to the cart 131 itself. The windshield becomes part of the stylized element and organically blends into the roof creating a natural ergonomic curve shape.
[0076] The MPPT solar controller 505 is wired directly into the solar panel 109 and wires extend laterally along the underside of the roof in a housed compartment and into the body of the vehicle and ultimately into the battery compartment. The benefit to this feature is the wiring harness is housed inside the upright of the cart which protects it from weather and the possibility of being bumped when people are reaching for items in the cart or golf clubs.
[0077] Thus it can be seen that roof assembly 1239 provides a light weight vehicles solar electric roof with benefits that include a reduction in the amount of grid charging required to maintain a charge in the batteries for operation. The reduction in electricity costs benefit the owners bottom line. Environmental impact of a facility utilizing these systems is greatly reduced. Benefits include less strain on the energy grid, reduced air pollution, reduced water pollution, reduction in land fill disposal of toxic batteries. Benefits to customers visiting/renting vehicle with solar electric charging system include: a reduction in the possibility of the vehicle “dying” during operation. This benefit includes a faster pace of play, avoiding the frustration of having to switch carts (to a cart with fresh batteries) in the middle of a round and avoiding the safety hazard of becoming stranded on a golf course while other golfers are trying to play through. Golf facilities utilizing these systems will experience a modern new look for their existing golf carts. This upgrade will help customers feel as if they are riding in a new modern vehicle without the cost of the facility having to replace the actual fleet of vehicles. Facilities can just replace their existing roof and uprights with roof assembly 1239 and enjoy a new fresh look and feel. With a modernized fleet of golf cars 131 a golf facility is may increase green fees helping its bottom line. The vertical uprights 1221 will emerge from the cart 131 at the designed locations for the most popular makes of golf carts. The uprights transform into a stylized element that is part of the roof system. In doing this, the roof system including the uprights 1221 will be able to maintain its distinct style even if the golf cart manufacturer changes its mounting scheme on the cart. The benefit include that it is not necessary to change any aspects of the roof itself should the mounting points of the uprights of the cart manufacturer change.
[0078] A microcontroller based electronic device 505 for charging the energy storage module (e.g. batteries) of a golf cart 131 from the roof mounted photo voltaic solar array 1239 . The device has features to maximize the utilization of the solar array, provide a “gas gauge” display of available energy, store a history of events and usage, and has a unique feature that interacts with the cart's motor controller to modulate the amount of power available to the cart driver to insure that enough energy is available to complete a round of golf.
[0079] The golf cart has an energy storage module typically made up of a number of batteries. These batteries are typically lead-acid chemistry, but could also be another battery chemistry or some other form of energy storage, all will be referred to as “battery”. The battery is to be charged via the solar array. MPPT device 505 has several algorithms that can be tailored for the type of battery and solar array to provide the most efficient use of the solar energy.
[0080] The device 505 monitors the energy flowing into the battery and out to the motor. The capacity and characteristics of the battery are known to the controller and therefore a very accurate estimation can be made of the available energy. An analogy is the gas gauge on an automobile. The computation of available energy is a complex interaction of not only power in (from the solar array), power out (to the motor), but of the rate of energy use i.e. in most battery systems, the apparent amount of stored energy becomes smaller as the rate of consumption becomes higher. In lead-acid chemistry, for example, this relationship is defined by Peukert's Law. The microcontroller is able to sample voltages and currents many times a second and calculate a complex formula and display the results to the cart driver instantaneously.
[0081] The device 505 stores a history of events and usage. This data is useful to the owners of the golf cart(s) to understand such things as energy savings provided by the solar array, operations potentially damaging to the battery, usage in relation to required servicing, and operational information that can be used to fine tune and improve the operation of the cart in the future. The device 505 uses some of this information internally to improve its MPPT algorithm and “gas gauge” function. Other information can be output to the cart's operator in the form of data that can be used for reporting and review.
[0082] The typical golf car 131 is used on a fixed course whose size is known. The golf car traverses typically 18 holes of golf and the average distance traveled by the cart is known. A sensor 1205 tracks the revolutions of the cart's wheels (alternately distance over ground may be computed from global position system (GPS) information) and the device 505 is able to determine the distance traveled. At any given time there is a certain amount of stored energy available in the battery. The device 505 computes the amount of distance required to complete the round of golf. If the cart's usage at full speed will exceed the available amount of energy available, the device will limit the output of the cart's motor to be able to safely cover the distance needed for completion. The calculation is updated frequently to account for varying conditions. For example, a cart in full sunshine would provide maximum charge to the battery allowing robust operation of the cart. Should the cart be under tree shade, or perhaps a cloudy day, the device 505 will modulate the motor power to extend the range of the cart to allow completion of the round of golf. This will prevent golfers from becoming stranded on the course.
[0083] Assembly 1239 may include features such as a charging point (e.g., USB); storage (e.g., phone pocket; rain gutters; handles; others; or any combination thereof.
INCORPORATION BY REFERENCE
[0084] References and citations to other documents, such as patents, patent applications, patent publications, journals, books, papers, web contents, have been made throughout this disclosure. All such documents are hereby incorporated herein by reference in their entirety for all purposes.
EQUIVALENTS
[0085] Various modifications of the invention and many further embodiments thereof, in addition to those shown and described herein, will become apparent to those skilled in the art from the full contents of this document, including references to the scientific and patent literature cited herein. The subject matter herein contains important information, exemplification and guidance that can be adapted to the practice of this invention in its various embodiments and equivalents thereof. | The invention provides an electrical vehicle power system that compares power use to anticipated need and regulates power use so that the anticipated need is satisfied by available power, thus ensuring ample power for a user to complete an activity such as playing a round of golf. The system uses a controller coupled to a photovoltaic cell on a golf car in a lightweight and durable solar roof apparatus that can retrofit to existing cars. | 8 |
BRIEF DESCRIPTION OF THE INVENTION
The invention relates to a sewing machine, and more particularly relates to a cycle pattern stitching device for a sewing machine having an intermittent (one-by-one) stitching mechanism. According to the invention a cycle stitch control device is designed to cooperate with the intermittent stitching device of the sewing machine to produce patterns of cycle stitches in accordance with pattern cams to be selected. By cycle stitching we mean that the sewing machine is automatically stopped with the needle located at a predetermined position when a selected pattern has been produced up to a predetermined number of stitches.
For attaining this object, the invention substantially comprises cycle stitch control means, regulating means cooperating with the cycle stitch control means to regulate the intermittent stitching device, and manually operated switching means for selecting one of the stitching modes including the cycle stitching, the intermittent stitching and the normal continuous stitching.
The conventional cycle stitching device has required electrical structures to automatically stop the sewing machine after a predetermined number of stitches has been formed. As far as we know, a cycle stitching mechanism without electric structures has not been provided. This kind of device incorporated with electric structures is often complex in structure and costly in production, and moreover has produced considerable troubles in operation.
This invention has been provided to eliminate such defects and disadvantages of the prior art.
It is a primary object of the invention to provide a cycle stitching device which is composed of mechanical elements requiring no electric structures.
It is another object of the invention to provide a cycle stitching device which is compact in structure and positive in operation.
It is another object of the invention to provide a cycle stitch control device cooperating with an intermittent stitching device to automatically stop the sewing machine after a pattern is formed.
Many other features and advantages of the invention will be apparent from the following description of the prefered embodiments and reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view of the invention shown partly in section,
FIG. 2 is a front elevational view of the invention shown partly in section,
FIG. 3 is a plan view of the invention with some parts eliminated,
FIGS. 4 and 5 are sectional views of a clutch mechanism in which the sections respectively are taken along two planes normal to each other,
FIG. 6 is an exploded view of FIGS. 4 and 5,
FIG. 7 is an exploded view of a stitch mode selecting part of the invention.
FIGS. 8, 8A-8D are side elevational views of a switch of the invention shown in different operation positions,
FIGS. 9-14 are side elevational views of the stitch mode selecting part of the invention shown in different operation positions,
FIG. 15 is an exploded view of a cycle stitch control mechanism of the invention,
FIG. 16 is a front elevational view showing a second embodiment of the invention,
FIG. 17 is a plan view showing part of FIG. 16,
FIG. 18 is an exploded view of the second embodiment of the invention,
FIGS. 19 and 20 are side views of the stitch mode selecting device of the second embodiment, and
FIG. 21 is an exploded view of a third embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
In reference to FIGS. 1-5, the sewing machine has an upper shaft 1 rotatably mounted in a machine housing 2. A sprocket 3 is secured to the upper shaft 1 by means of a pin 4 for driving a lower shaft (not shown) through a timing belt as shown in FIG. 6. A bushing 5 is secured to the upper shaft 1 by means of a screw 6. A stop cam 7 is mounted on the upper shaft 1 between the sprocket 3 and the bushing 5, and is normally biased by a torsion spring 8 in the counterclockwise direction in FIG. 1. A pair of screws 9 are threaded into the bushing through a spacer 10, and each has a head respectively extending into two opposed arcuate slots 11 formed in the stop cam 7 as shown. Thus the heads of the screws 9 abut against the cushions 12 each provided at the ends of the respective slots 11 of the stop cam 7, thereby to normally stop the counterclockwise movement of the stop cam 7.
A pulley 13 is rotatably mounted on the bushing 5, and a knob 15 is mounted on the bushing 15 and is secured to the end of the upper shaft 1 by means of a screw 16 with a spacer 14 placed between the pulley 13 and the knob 15. As shown in FIG. 6, the bushing 5 is formed with an axially extended groove 19. A platelet 17 is secured to the botton of the groove 19 by a stepped screw 20, and a clutch lever 18 is turnably arranged on the platelet 17 by the stepped screw 20. The free end 18a of the clutch lever 18 is inserted into a slot 7a of the stop cam 7. As shown, the cluth lever 18 is normally biased in the counterclockwise direction by a torsion spring 23. The clutch lever 18 is formed with a rectangular hole 21 in which a roller 22 is placed. The roller 22 is normally placed on the higher part of a slope 24 of the platelet 17 and connecting the bushing 5 and the inner periphery 13a of the wheel 13, thereby to transmit the rotation of the pulley 13 to the upper shaft 1. Therefore, if the clutch lever 18 is turned in the clockwise direction against the action of the torsion spring 23, the roller is displaced from the higher part of the slope 24 to a lower part of the groove 19 in which the roller 22 is spaced from the inner periphery 13a of the pulley. In this case, the rotation of the pulley 13 is not transmitted to the upper shaft 1.
As shown in FIG. 1, an intermediate pulley 25 is provided. The pulley 25 is connected to a machine drive motor (not shown) by means of a belt 26. The pulley 25 is formed with a coaxial small pulley 25a which is connected to the pulley 13 by means of another belt 27, so that the driving power of the machine drive motor may be transmitted to the pulley 13. Thus the pulley 13 is rotated in the direction as indicated by an arrow A. As shown in FIGS. 1, 2 and 7, a bracket 28 for a machine stopping mechanism is secured to the machine housing 2 by means of upper and lower screws 29, 30. The screw 29 has a nut 29a mounted at the intermediate part thereof. A stop lever 31 is turnably mounted on the screw 29 on one side of the nut 29a and is prevented from axial displacement by a snap ring 32. The stop lever 31 is normally biased in the counterclockwise direction by a spring 33 (in FIGS. 1 and 7), and the upper end 31a of the stop lever 31 is normally located at a position spaced from the rotation path of the stop cam 7. The stop lever 31 is formed with a forked part 34 at the lower end thereof. An operating lever 36 is turnably mounted on a pin 35 provided on the bracket 28, and has a pin 37 secured to the free end thereof. The pin 37 is in engagement with the forked part 34 of the stop lever 31, so that the operating lever 36 may be operated to turn the stopper lever 31 relative to the stopper cam 7.
As shown in FIGS. 1, 7-9, a switch activating lever 38 is turnably mounted on the pin 35 of the bracket 28 and is normally biased in the clockwise direction by a tension spring 39. A pin 40 secured to the switch activating lever 38 is extended through a hole 41 of the bracket and is kept in engagement with a cam 43 of a turnably arranged switching lever 42 to locate the lateral projection 44 of the lever 42 at a position adjacent to an operating button 46 of a switch 45. Thus the switch 45 is normally inoperative. A manually accessible operating lever 47 is turnably mounted on the free end of the pin 35 of the bracket 28 and is prevented from displacement axially of the pin 35 by a washer 48. The operating lever 47 and the other operating lever 36 are connected to each other by a torsion spring 49 which normally biases the former in the clockwise direction and the latter in the counterclockwise direction. The operating lever 36 is normally pressed against an abutment part 47b of the operating lever 47 and thus the two levers are operated together. On the other hand, the operating lever 47 is biased in the clockwise direction by a tension spring 50, and the part 47a thereof is pressed against an abutment 28a of the bracket 28. Thus the operating lever 47 and the other lever 36 are normally positioned as shown in FIG. 1, in which the pin 37 of the lever 36 is idle in the forked part 34 of the stop lever 31.
The operating lever 47 has a pin 51 secured thereto. A pawl 52 is turnably mounted on the pin 51 and is normally biased in the clockwise direction by a spring 53. The pawl 52 has a projection 54 which is normally pressed against an abutment 47c of the operating lever 47, and is also in engagement with a cam 55 of the switch activating lever 38. The bracket 28 has another pin 56 secured thereto on which a releasing pawl 57 is turnably mounted and is normally biased in the clockwise direction by a spring 58. When the operating lever 47 is brought to an medium position as shown in FIG. 9, the upper end 59 of the releasing pawl 57 is pressed against the operating lever 36. The operating lever 36 has an adjusting element 60 secured to the lower end thereof by a screw 61. The adjusting element 60 and the lower end 62 of the releasing pawl 57 are spaced from each other when the operating lever 47 is in the upper inoperative position as shown in FIG. 1 or in the medium position as shown in FIG. 9. However, in the position of FIG. 9, the pawl 52 is operated to press, by way of the switch activating lever 38, the projected end 44 of the switching lever 42 against the button 46 of the switch 45 as shown in FIG. 8A. Thus the switch 45 becomes operative.
As shown in FIG. 10, if the operating lever 47 is brought to the lower position, the other operating lever 36 is operated to turn the stop lever 31 in the clockwise direction against the action of the spring 33 toward the rotation path of the stop cam 7 which is formed with an abutment 63. Simultaneously the adjusting element 60 at the end of the operating lever engages the lower end 62 of the releasing pawl 57, and the upper end 59 of the releasing pawl 57 comes to engage the side 64 of the pawl 52 as will be understood from FIG. 7. As the sewing machine is driven and the abutment 63 of the stop cam 7 comes to be blocked by the end 31a of the stop lever 31, as shown in FIG. 11, the adjusting element 60 turns the releasing pawl 57 in the counterclockwise direction, thereby to disengage the projection 54 of the pawl 52 from the cam 55 of the switch activating lever 38. The switch activating lever 38, therefore, releases the switching lever 42, and thus the switching lever 42 is disengaged from the button 46 of the switch 45 as shown in FIG. 8C, and the switch is opened to be inoperative.
In reference to FIG. 7, an operating knob 66 is secured to the free end of the operating lever 47. The switch 45 is contained in a switch case composed of a pair of housing members 67 and a cover 70, which are secured to the bracket 28 by a pair of screws 71.
The operation of the foregoing mechanism is as follows; If the operating lever 47 is displaced to the upper inoperative position as shown in FIG. 1, the sewing machine is driven with a desired speed in the range from a high speed to a low speed by operation of an operator-controlled switch (not shown).
If the operating lever 47 is displaced to the medium position as shown in FIG. 9 immediately after the operator-controlled switch is released or during the time the operator-controlled switch is operated, the pawl 52 turns the switch activating lever 38 in the counter-clockwise direction against the action of the spring 39. As the result, the pin 40 of the switch activating lever 38 which is in engagement with the cam 43 of the switching lever 42, is displaced from a higher position as shown in FIG. 8 to a lower position as shown in FIG. 8A. Thus the pin 40 turns the switching lever 42 in the counterclockwise direction to press the same lever against the button 46 of the switch, and then the switch becomes operative. In this condition, the sewing machine is designed to rotate at a lower speed irrespectively of operation of the operator-controlled switch. In this case, the operating lever 36 has no influence on the stop lever 31.
If the operating lever 47 is displaced to the lower position as shown in FIG. 10, the operating lever 36 turns the stop lever 31 in the clockwise direction against the action of the torsion spring 33. The end 31a of the stop lever 31 comes to engage the outer periphery of the abutment part 63 of the stop cam 7, as shown, if the needle is not just at the upper dead point thereof. In this case, the pin 40 of the switch activating lever 38 further comes down as shown in FIG. 8B, and thus the switch 45 remains to be operated. Simultaneously the adjusting element 60 at the lower end of the operating lever 36 will engage the lower end 62 of the releasing pawl 57. When the sewing machine makes one rotation and the end 31a of the stop lever 31 engages the abutment 63 of the stop cam 7 as shown in FIGS. 11 and 12, the operating lever 36 further turns the stop lever 31 in the clockwise direction by a force stored in the torsion spring 49 (FIG. 1). Therefore, the adjusting element 60 at the lower end of the operating lever 36 turns the releasing lever 57 in the counterclockwise direction. As the result, the releasing pawl 57 turns the pawl 52 in the counterclockwise direction to release the projection 54 from the cam 55 of the switch activating lever 38. Then the switch activating lever 38 is turned in the clockwise direction by the tension spring 39, and the pin 40 is, therefore, displaced, relative to the cam 43 of the switching lever 42, to the upper inoperative position as shown in FIGS. 8C and 8D. Then the switching lever 42 is turned in the clockwise direction by a spring (not shown), and therefore, the lateral projection 44 of the switching lever 42 is displaced to a position spaced from the switch 45. Thus the switch 45 becomes inoperative, and the electric current to the machine drive motor is blocked. The upper shaft 1 of sewing machine is, however, rotated by its own inertia, even when the stop cam 7 is blocked by the stop lever 31 as shown in FIG. 12. Namely the upper shaft 1 is rotated against the action of the cushion spring 8 connecting the stop cam 7 and the upper shaft 1 and biased in one direction due to the engagement of the stop cam 7 and the stop lever 31 as shown in FIGS. 4 and 5, and the inertia of the upper shaft 1 is absorbed by the spring 8 until the stop screws 9 abut against the cushions 12 respectively which are provided at the respective ends of the slots 11 of the stop cam 7 as shown in FIG. 6. At the same time, the clutch lever 18 (FIG. 6) is displaced in the clockwise direction against the action of the spring 23, and the roller 22 in the groove 19 of the bushing 5 is displaced from the position, in which it connects the upper shaft 1 to the pulley 13, to the position in which it disconnect the upper shaft 1 from the pulley 13. Thus the sewing machine is stopped with a predetermined angular position of the upper shaft 1, that is, with a predetermined position of the needle.
Then if the operating lever 47 is released, the lever is returned, by the action of the torsion spring 49, to the initial inoperative position, and thus the relating elements are all returned to the initial position as shown in FIG. 1. If the operating lever 47 is displaced to the medium position again, the sewing machine is driven at a low speed. On the other hand, if the operating lever 47 is repeatedly displaced between the upper inoperative position and the lower operative position, the sewing machine is intermittingly driven at a low speed to produce one-by-one stitches or basting stitches.
The above described mechanism can be utilized to produce the patterns of cycle stitches together with an additional mechanism.
In reference to FIGS. 1, 2 and 3, the upper shaft 1 has a worm 81 secured thereto. The worm 81 is in mesh with another worm 80 secured to a transverse shaft 83, so that the transverse shaft 83 may be rotated by the upper drive shaft at a reduced speed. A group of pattern cams 82 are secured to the transverse shaft 83 for rotation therewith. An elongated U shaped frame 84 is secured to the machine housing 2 carrying a mounting shaft 87 secured to the U shaped frame by a nut 86 between the two arms 84a, 84b thereof as shown in FIG. 3. An elongated U shaped lever 85 is turnably mounted on the shaft 87. The lever 85 is, at one end, provided with a depending follower arm 85a carrying a pin 84 at the lower end thereof, and is, at the other end, provided with another depending arm 85b which is located adjacent to the stop lever 31 to cooperate with a pin secured to the latter. A U shaped element 88 is turnably mounted on the shaft 87 between the two arms 85 a, 85b of the U shaped lever 85. A part of the U shaped element 88 is located just below a projection 85c of the lever 85 so as to cooperate with the latter as will be mentioned. The U shaped element 88 is prevented from movement axially of the shaft 87 by a pair of washers 89 as shown. A spring 90 is provided between one end of the U shaped element 88 and the arm 85a of the U shaped lever 85 to normally bias the latter in the leftward direction.
A cycle stitch control cam 91 is provided on the transverse shaft 83 at the forward end of the pattern cam group 82. The cycle stitch control cam 91 is, at the front side thereof, formed with a groove 92 extending radially and circumferentially as shown in FIG. 2. On both sides of the groove 92, slopes 92a, 92a are provided, each extending from the botton of the groove 92 up to the front face of the control cam 91 to guide the pin 94 of the U shaped lever 85 as will be mentioned. The U shaped lever 85 is normally biased in the counterclockwise direction as viewed in FIG. 13 by a spring 95 as shown in FIG. 15, so that the pin 94 of the lever 85 may be normally pressed against the front face of the control cam 91 as shown in FIG. 2, and so that the arm 85b of the lever 85 may be located at a position adjacent to the pin 96 on the stopper lever 31 as shown in FIG. 13.
A transverse control shaft 97 is rotatably mounted on the machine housing 2 as shown in FIGS. 1 and 2. An operating dial 98 is secured to the forward end of the control shaft 97 which projects out of the machine housing 2. Marks for the intermittent stitches and the cycle stitches are provided on the front face of the dial 98 in the positions diametrically opposite to each other in relation to a set mark provided on the machine housing as well known, though these marks are not shown. A selecting cam 103 and an operating cam 102 are secured to the control shaft 97. A follower 107 is secured to the U shaped lever 85 by a screw 106, and is pressed against the selecting cam 103 by the action of the spring 90. On the other hand, a follower pin 105 is secured to the U shaped element 88 by a nut 104, and is pressed against the operating cam 102 by a spring (not shown) which normally biases the U shaped element 88 in the counterclockwise direction as viewed in FIG. 1.
The cycle stitching mechanism is operated as follows; FIGS. 2 and 13 show that the cycle stitching has been selected. Namely, the U shaped lever 85 has been displaced from the position shown by the imaginery line to the position shown by the solid line in which the pin 94 is pressed against the front face of the control cam 91 at the circumferential effective region 93 thereof. This displacement of the U shaped lever 85 is carried out by manual operation of the dial 98. Namely, the operating cam 102 turns the U shaped element 88 in the clockwise direction in FIG. 1, thereby to turn the U shaped lever 85 in the clockwise direction to displace the pin 94 in a plane forwardly of the front face of the control cam 91. Simultaneously the U shaped lever 85 is displaced in the leftward direction in accordance to the configuration of the selecting cam 103 due to the spring 90 until the pin comes to the effective range 93 of the control cam 91. Then the U shaped element 88 is allowed to turn in the opposite direction by the configuration of the operating cam 102. Thus the pin 94 is pressed against the control cam 91 as shown in FIG. 2.
In this condition, if the operating lever 47 is displaced to the lower set position as shown in FIG. 13, the stop lever 31 remains in the inoperative position because the clockwise movement of the stop lever 31 is prevented by the lower end 85d of the depending arm 85b of the U shaped lever 85. When the upper shaft 1 makes a predetermined number of rotations, for example, if the group of pattern cams 82 makes one complete rotation while the upper shaft 1 makes one complete rotation, the pin 94 of the U shaped lever 85 is dropped into the groove 92 of the control cam 91. Then the U shaped lever 85 is turned in the counterclockwise direction, and allows the stop lever 31 to turn in the clockwise direction as shown in FIG. 11. Then when the rotation of the stop cam 7 is blocked by the stop lever 31 as shown in FIG. 12, the sewing machine is stopped with the needle located at a predetermined position in the manner as aforementioned.
Then, if the operating lever 47 is displaced again in the upper inoperative position, the stop lever 31 is returned to the inoperative position spaced from the rotation path of the stop cam 7. Therefore, if the sewing machine is driven with a repeated operation of the operating lever 47 between the upper inoperative position and the lower operative position, a pattern of cycle stitches is repeatedly produced, and the pattern may be varied in dependence upon a selected one of the pattern cams 82.
FIGS. 16-20 show another embodiment of the invention which is different from the first embodiment in the following points; According to the other embodiment, a cycle stitch operating lever 110 and an intermittent stitch operating lever 111 are turnably mounted on the support pin 35' of the bracket 28'. These operating levers 110, 111 are normally biased in the clockwise direction by springs 112 respectively. The cycle stitch operating lever 110 has a cam 110a with a cam lift S formed at the inner end thereof, which is to be pressed against the right side of the stopper lever 31 as shown in FIG. 16. A pin 47'a of the operating lever 47' is pressed against the underside of the arms 110b and 111a of the respective levers 110, 111 by a tension spring 50. As shown in FIG. 16, the U shaped lever 85' is prevented from displacement axially of the support shaft 87', and the pin 94' are usually pressed against the front face of the control cam 91, and the depending arm 85'b are located at a position spaced from the pin 96 of the stopper lever 96. The stopper lever 31 is laterally displacable against the action of the spring 33'.
If the cycle stitch operating lever 110 is displaced from the upper inoperative position to the lower operative position, the operating lever 47' is also displaced to the lower operative position. Simultaneously the stopper lever 31 is displaced in the leftward direction against the action of the spring 33' by the cam lift 110a of the lever 110. Therefore, the stopper lever 31 is prevented from turning movement in the clockwise direction, by the depending arm 85'b, and remains to be in the inoperative position in the same manner as shown in FIG. 13. Then, if the sewing machine is driven and the control cam 91 together with the pattern cams 82 are rotated, and when the pin 94' of the U shaped lever 85' is dropped into the groove 92 of the control cam 91, then the U shaped lever 85' is turned in the clockwise direction and the stopper lever 31 is released to rotate in the clockwise direction toward the rotation path of the stopper cam 7 as shown in FIG. 20. Thus the cycle stitching can be repeatedly carried out by repeated operation of the cycle stitch operating lever 110 between the upper inoperative position and the lower operative position.
FIG. 21 shows still another embodiment of the invention, in which a single operating lever 113 is employed in place of the cycle stitch operating lever 110 and the intermittent stitch operating lever 111 of the second embodiment, and the bracket 28' is formed with an upstanding projection 28'c. The operating lever 113 is laterally displaceable on the support pin 35' of the bracket 28'. Thus, if the arm 113b of the operating lever 113 is displaced to the left side of the upstanding projection 28'c of the bracket 28', the free end part 113a of the lever 113 displaces the stopper lever 31 (in FIG. 16) in the leftward direction against the action of the spring 33' in the same manner as in the second embodiment. Then, if the operating lever 113 is displaced from the upper inoperative position to the lower operative position, the operating lever 47' is also displaced in the same manner as in the second embodiment. On the other hand, if the operating lever 113 is displaced to the right side of the upstanding projection 28'c, the U shape lever 85' becomes inoperative. Then, if the operating lever 113 is displaced to the lower operative position, the operating lever 47' is also displaced to the lower operative position. Thus the intermittent stitching mode is selected. | A sewing machine comprises an upper shaft adapted in a known manner to reciprocate the needle of the sewing machine. A motor-driven pulley is freely turnable on the shaft and normally connected to the latter by a clutch. A stop cam having an engaging face is fixed to the shaft for rotation therewith and a stop lever is movable by a manually operated lever between an inoperative position located out of the path of rotation of the engaging face and an operating position in the path of the latter to stop rotation of the cam and therewith the shaft upon engagement of the stop lever with the engaging face. Elements cooperating with the stop cam cooperate with the clutch to disconnect the pulley from the shaft when the stop lever blocks rotation of the stop cam. Regulating elements cooperate with a cycle stitch control cam driven by the shaft with a predetermined speed to normally hold the stop lever in the inoperatives position and the stitch control cam moves the regulating elements in a direction to release the blocked lever after a predetermined number of revolutions of the shaft.
The sewing machine includes further a switch in circuit with the motor driving the pulley and elements cooperating with the manually operated lever for switching off the motor when the stop lever stops rotation of the stop cam, and manually adjustable cams for moving the regulating elements between an inoperative position spaced from the stitch control cam and an operative position engaging the latter. | 3 |
BACKGROUND OF THE INVENTION
The invention relates to a continuous casting mold for the continuous casting of a steel billet, preferably for the casting of thin slabs of a thickness of less than 100 mm, with wide side walls located opposite one another and with narrow side walls which are arranged clampably between the wide side walls and displaceably along the wide side walls transversely to the casting direction and are located opposite one another and which narrow in a wedge-shaped manner in the casting direction. The wide side walls have a funnel-shaped pouring-in region which extends in the casting direction as far as the mold end, and the distance between the wide side walls is reduced continuously, at least over part regions of their extent, in the direction of the narrow side walls and in the casting direction, and the wide side walls are designed to converge.
A continuous casting mold of the generic type is already known from DE-C 35 01 422. Its wide side walls are designed to converge in the direction of the narrow side walls and in the casting direction. The wide side walls have, in the region of adjustment of the narrow side walls, planar contact faces which cooperate with the side walls of the narrow side walls. When format adjustment is to be carried out in the mold, this usually involves a displacement of the narrow side walls with the effect of changing the width of the steel billet to be cast.
The billet thickness and consequently the distance between the wide side walls are in this case to be kept constant. However, during format adjustment of the known continuous casting mold, it is possible to keep the distance between the wide side walls constant only when the narrow side walls are offset both in the horizontal and in the vertical direction. Designing the wide side walls in the region of adjustment of the narrow side walls with a planar surface makes it necessary for the latter to be in a skew position with respect to the mold longitudinal axis. Due to these geometric restrictions, it is no longer possible for the exit cross section to be configured in such a way that, for each billet format to be cast, the billet thickness is constant over the entire billet width.
EP 0 658 387 A1 also discloses a continuous casting mold, the wide side walls of which are designed to converge in part regions in the direction of the narrow side walls and in the casting direction. The wide side walls have, in the region of adjustment of the narrow side walls, planar surface contours which cooperate with the side faces of the narrow side walls and the distance between which decreases linearly in the direction of the narrow side walls and is constant in the casting direction. In the event of a displacement of the narrow side walls with the effect of changing the wide sides of the steel billet to be cast, this embodiment also automatically necessitates an adjustment of the thickness of the latter in a ratio permanently predetermined by the geometry. However, the range of billet formats to be cast by means of a continuous casting mold of this type is consequently restricted in an undesirable way.
SUMMARY OF THE INVENTION
The object of the invention is, therefore, to avoid these disadvantages described above and to propose a continuous casting mold with a funnel-shaped pouring-in region, said mold allowing format adjustment in which the billet width of the billet to be cast can be set without any repercussion on the billet thickness and the billet thickness of the billet to be cast can be kept constant over the entire billet width.
This object is achieved, according to the invention, in that the distance between the wide side walls at the mold end is constant over the entire width of the wide side walls and at least one of the wide side walls is arranged on a mold carrying structure displaceably and tiltably with respect to the opposite wide side wall and is connected to an adjusting device. As compared with funnel molds in which the wide side walls are located opposite one another in a plane-parallel manner in the region of adjustment of the narrow side walls, the converging run of the wide side walls in the region of adjustment results in smaller curvatures in the funnel-shaped pouring-in region and consequently in the easy formation of a billet shell.
The proposed mold geometry, aimed particularly at the low-stress and therefore crack-free formation of a billet shell, gives rise, during format adjustment, to a wedge-shaped gap between the wide side wall and the narrow side wall, which, however, amounts at most to only a few millimeters and can easily be compensated by means of the tilting movement of the wide side wall. If one of the two wide side walls located opposite one another is firmly anchored on the mold carrying structure and thus forms a fixed side, the narrow side wall arranged between these two walls is also tilted by means of the displaceable and tiltable wide side wall and in this way a gap-free mold cavity for the reception of melt is formed for each adjustable billet format.
The tilting of the narrow side walls when they are clamped between the wide side walls is avoided and the necessary tilting angle for the wide side wall is halved when each of the wide side walls is arranged displaceably and tiltably on a mold carrying structure and is connected to an adjusting device.
In an expedient embodiment of the continuous casting mold, the wide side walls located opposite one another are connected to an adjusting device covering both wide side walls. In a special design solution, the tiltable wide side wall is connected to the adjusting device in an articulated manner.
Optimum conditions in the continuous casting mold are obtained for the formation of a billet shell when, with respect to a horizontal plane incorporating the casting level under constant casting conditions, the inclination ∝ 1 of the wide side wall in the funnel-shaped pouring-in region is 1° to 5° and the inclination ∝ 2 of the wide side wall in the region of adjustment of the narrow side wall is between 0.1° and 0.3°.
In continuous casting technology, it is generally customary to clamp the narrow side walls between the wide side walls by means of a casting cone which is format-dependent, that is to say dependent on the casting width, the casting cone being adapted during format adjustment to the new billet format in each case. According to the teaching given in DE-C 35 01 422, it is advantageous for the narrow side walls to be arranged between the wide side walls in a position in which they diverge from one another in the casting direction. Both the mass flow of the steel in the direction of the narrow side walls and the cooling-related contraction of the billet may be taken into account in defining the casting cone.
A simple design of the continuous casting mold according to the invention is achieved in that each wide side wall is fastened releasably to a supporting wall and the adjusting device is connected to at least one of the supporting walls, which are displaceable and tiltable jointly with the wide side wall. The coolant ducts for mold cooling are worked into the wide side wall or the supporting wall in the form of coolant slots along the contact plane between the wide side wall and the supporting wall.
According to an alternative embodiment, a carrier wall is arranged between the wide side wall and the supporting wall, the wide side wall being fastened releasably to the carrier wall and the carrier wall being fastened releasably to the supporting wall. The coolant ducts for mold cooling are worked into the wide side wall or into the carrier wall in the form of coolant slots along the contact plane between the wide side wall and the carrier wall. By means of this embodiment, it is possible to preassemble the wide side wall jointly with the carrier wall and with the integrated coolant lines as a structural unit and to install it in the continuous casting mold in a simple way.
In order to meet the need for discharging the heat in the continuous casting mold differently in different zones, it is proposed, according to a preferred embodiment, that the geometry of the coolant ducts in the funnel-shaped pouring-in region of the wide side walls and the geometry of the coolant ducts in the region of adjustment of the narrow side walls be different. What is to be understood by the geometry of the coolant ducts is, on the one hand, the distance between the coolant ducts and, on the other hand, the clear width (cross-sectional area) of the coolant ducts and consequently the coolant flow velocity or the combination of the two influencing variables. The specific heat flux density of the wide side walls is varied as a result of both measures. According to a further possible embodiment, this is achieved in that groups of adjacent coolant ducts are conductively connected to individually activatable coolant stations, the funnel-shaped pouring-in region and the regions of adjustment of the narrow side walls of each wide side wall each being assigned at least one coolant supply station.
In order to allow an optimum discharge of heat in the continuous casting mold, it is advantageous for at least those inner walls of the wide side walls which form the mold cavity to be formed by different materials in the casting direction, the material used in the region of the casting level having a lower thermal conductivity than the material used for the portion of the wide side walls which follows in the casting direction. For example, in the region of the casting level, where particularly high temperatures occur and solidification is not required immediately, the wide side walls consist of nonferrous metals, refractory materials or various combinations of these.
It is particularly cost-effective and operationally reliable to equip the adjusting devices for the wide side walls and the narrow side walls with electromechanical or hydraulic drives.
Favorable conditions for the starting operation and for stress-free formation of a billet shell are likewise obtained when the contour of the wide side walls in the funnel-shaped pouring-in region is shaped parabolically in the casting direction. A further improvement in these conditions arises when the contour of the narrow side walls is also shaped parabolically in the casting direction and the narrow side walls are provided on both sides with edge clearances in a region which extends below the casting level as far as the mold exit.
Further advantages and features of the present invention may be gathered from the following description of unrestrictive exemplary embodiments, reference being made to the accompanying diagrammatic figures, which show the following:
DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a first embodiment of the continuous casting mold according to the invention with one fixed side and one loose side,
FIG. 2 shows a second embodiment of the continuous casting mold according to the invention with two loose sides,
FIG. 3 illustrates, in a half section, the mold geometry in the case of a continuous casting mold according to the first embodiment and the displacement of the mold walls during format adjustment,
FIG. 4 illustrates, in a half section, the mold geometry in the case of a continuous casting mold according to the second embodiment and the displacement of the mold walls during format adjustment,
FIG. 5 shows, in a vertical section along the line A—A of FIG. 3, the displacement of the movable wide side wall in the case of a continuous casting mold according to the embodiment shown in FIGS. 1 and 3,
FIG. 6 shows, in a vertical section along the line B—B of FIG. 4, the displacement of the movable wide side walls in the case of a continuous casting mold according to FIGS. 2 and 4,
FIG. 7 a shows a diagrammatic illustration of the design of a mold wide side in a first embodiment, with one possible embodiment of the coolant supply,
FIG. 7 b shows a diagrammatic illustration of the design of a mold wide side in a second embodiment, with one possible embodiment of the coolant supply,
FIG. 8 shows the cross section of a wide side wall in the funnel-shaped pouring-in region with a parabolic inner contour,
FIG. 9 shows the cross section of a narrow side wall with a parabolic inner contour and with edge clearance.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1 and 2 illustrate diagrammatically two basic embodiments of continuous casting molds according to the invention for the production of a steel billet, identical components being given identical reference symbols. Two wide side walls 1 , 2 and two narrow side walls 3 , 4 of a continuous casting mold form a mold cavity 5 , into which steel melt is introduced via a pouring spout, not illustrated, and out of which a partially solidified steel billet is conveyed from the continuous casting mold in the casting direction. The wide side walls 1 , 2 and the narrow side walls 3 , 4 are conventionally produced from copper or a copper alloy or from another material having very good thermal conductivity. The wide side walls 1 , 2 are supported on supporting walls 7 , 8 and are screwed to these. In a similar way, the narrow side walls 3 , 4 are supported on and screwed to supporting walls, not illustrated. In order to set different casting formats, the narrow side walls 3 , 4 positioned between the wide side walls 1 , 2 are displaceable transversely to the casting direction 6 , one possible position being illustrated by broken lines. For carrying out this adjusting movement, the narrow side walls 3 , 4 are connected by their vertical end regions to narrow-side adjusting devices 9 , 10 in an articulated manner and are counter mounted on the firmly anchored mold carrying structure 11 . These narrow-side adjusting devices are not illustrated for the narrow side wall 4 . The mutually opposite supporting walls 7 , 8 of the wide side walls 1 , 2 have passing through them tie rods 14 , 15 of the adjusting devices 12 , 13 and are capable of being fixed relative to one another, the narrow wide side walls 3 , 4 being clamped or released between the wide side walls 1 , 2 when action is taken on these adjusting devices 12 , 13 . For carrying out these manipulations, each adjusting device 12 , 13 is assigned a separately activatable pressure-medium cylinder 16 . The narrow side walls 3 , 4 are narrowed in a wedge-shaped manner in the casting direction 6 . In principle, the adjusting devices 9 , 10 , 12 , 13 may be equipped with any desired electromechanical or hydraulic drives.
In the embodiment of the continuous casting mold illustrated in FIG. 1, the wide side wall 2 is designed as a fixed side, that is to say it occupies, together with the supporting wall 8 , a clearly defined position in relation to the mold carrying structure 11 . The loose side formed by the wide side wall 1 and the associated supporting wall 7 is supported on guides 17 in the mold carrying structure 11 so as to be displaceable transversely to the casting direction 6 and is capable of being pressed by means of the adjusting devices 12 , 13 against the narrow side walls 3 , 4 and, together with these, against the firmly positioned wide side wall 2 , this taking place as a result of displacement in the direction of the guides 17 and tilting about the lower or upper inner edge 18 , 18 a of the wide side wall 1 .
In the embodiment of the continuous casting mold illustrated in FIG. 2, both wide side walls 1 , 2 are designed as loose sides and are supported on guides 17 in the mold carrying structure 11 so as to be displaceable transversely to the casting direction 6 and are capable of being pressed by means of the adjusting devices 12 , 13 on both sides against the narrow side walls 3 , 4 , this taking place as a result of displacement in the direction of the guides 17 and tilting about the lower or upper inner edge 18 , 18 a , 19 , 19 a of the wide side walls 1 , 2 .
FIGS. 3 and 4 show, in a horizontal section through the continuous casting molds according to FIGS. 1 and 2, which is taken in the region of the casting level, the geometric conditions in this region of the continuous casting mold and their variations during format adjustment. What is designated in this context by casting level is the surface of the liquid melt introduced into the continuous casting mold, this casting level always being kept at approximately the same height in the continuous casting mold under constant casting conditions.
In order to achieve a clear illustration, only the inner edges of the wide side walls 1 , 2 are illustrated in FIGS. 3 and 4. The centrally placed funnel-shaped pouring-in region 20 has adjoining it on both sides a region of adjustment of the narrow side walls 21 , 22 , the narrow side walls 3 , 4 being positioned displaceably within this region of adjustment.
In FIG. 3, the narrow side wall 4 is illustrated by unbroken lines for a first billet format and the wide side walls 1 , 2 are adapted to this with likewise unbroken lines. The narrow side wall 3 is illustrated by broken lines in the left half of the figure for a smaller billet format. The displacement movement of the narrow side wall 3 is indicated by the arrow 23 which symbolizes the narrow-side adjusting devices 9 , 10 from FIG. 1 . The wide side wall 1 is designed as a loose side and is tilted and pressed down in the direction of the arrow 24 , which symbolizes the adjusting devices 12 , 13 from FIG. 1, toward the fixed side formed by the wide side wall 2 , as illustrated by broken lines. The tilting movement takes place, here, about the lower inner edge 18 of the wide side wall 1 . The lower inner edge 18 , which defines a portion of the exit cross section from the continuous casting mold, does not change its position as a result of format adjustment, so that the billet thickness in the exit cross section always remains constant, unchanged by desired billet formats. In FIG. 5, the change in position of the wide side wall 1 , brought about by the tilting movement about the lower inner edge 18 , is illustrated by broken lines.
FIG. 4 illustrates in a similar way the conditions in the situation where both wide side walls 1 , 2 form two loose sides, as already illustrated in FIG. 2 . In this case, during format adjustment, which is made clear by the narrow side wall 3 illustrated by broken lines, there is a synchronous tilting of the two wide side walls 1 , 2 into the position illustrated by broken lines in the left half section. The entire continuous casting mold remains in a position symmetrical to the central casting axis 25 . The narrow side walls 3 , 4 do not change their vertical orientation. FIG. 6 illustrates by broken lines the changes in position of the two wide side walls 1 , 2 which are brought about by the tilting movement about the lower inner edges 18 .
The planar wall inner parts of the wide side walls 1 , 2 , which have different inclinations to one another, are matched by means of arcuate transitions R 1 , R 2 . The inclination ∝ 1 of the wide side walls 1 , 2 in the funnel-shaped pouring-in region 20 is in the region of 1 to 5° and the inclination ∝ 2 of the wide side walls in the region of adjustment of the narrow side walls 21 , 22 is in the region of 0.10 to 0.30. The best possible conditions for the formation of a billet shell are thus afforded.
The structural design of the wide side of a continuous casting mold is illustrated diagrammatically in FIGS. 7 a and 7 b . Each wide side wall 1 , 2 is fastened either directly to a supporting wall 7 , 8 releasably by means of screw connections (FIG. 7 b ) or to said supporting wall, with a carrier wall 27 interposed, and both walls are jointly fastened releasably to a supporting wall 7 , 8 (FIG. 7 a ). Coolant ducts 26 are worked into each wide side wall 1 , 2 in a groove-shaped manner, so as to be parallel to one another and to follow the casting direction vertically. However, they may also be worked into the supporting wall 7 , 8 or carrier wall 27 resting against the wide side wall, as described above with regard to the wide side wall. This variant is illustrated by broken lines in FIGS. 7 a and 7 b . In order to achieve a cooling action which is different in different sections, the geometry of the coolant ducts 26 deviates in their cross section and/or the distance between them in the funnel-shaped pouring-in region from the region of adjustment of the narrow side walls. The same effect can be achieved when the coolant ducts 26 are connected in groups to coolant supply stations 28 , with the result that the throughflow velocity in the coolant ducts 26 becomes variable.
The wide side walls 1 , 2 are designed parabolically in the casting direction 6 in the funnel-shaped pouring-in region 20 (FIG. 8 ). As illustrated in FIG. 9, the narrow side walls 3 , 4 have a surface contour which, in particular, is designed parabolically on the pouring-in side, edge clearances 30 being additionally arranged on both sides in a region 29 which extends below the casting level as far as the mold exit. These edge clearances are already described in detail in AT-B 404 235. | A continuous casting mold for continuous casting of a steel billet. Opposite spaced apart wide side walls and opposite spaced apart narrow side walls between the wide side walls and clampable at the wide side walls and also displacable along the wide side walls transversely to the casting direction, the narrow side walls being narrow wedged-shaped in the casting direction. A funnel-shaped pouring-in region defined in the wide side walls. The wide side walls converge in the casting direction. The distance between the wide side walls at the mold end is constant over the entire width of the side walls allowing at least one of the wide side walls is supported to be displaceable and tiltable with respect to the other wide side wall by an adjusting device. | 1 |
BACKGROUND
1. Field of Art
[0001] This invention relates generally to computer-implemented knowledge management systems and more specifically to computer systems that recommend to users of documents in document corpora.
2. Description of the Related Art
[0002] Current computing systems make available vast quantities of digital documents, such as articles, technical talks, Wiki pages, slide shows, and the like. The sheer quantity of available data can make it difficult for users to locate the documents that are most pertinent to their particular interests. Recommendation systems address this problem by presenting the users with a selected set of documents chosen based on some prior knowledge of the user's interests.
[0003] However, conventional recommendation systems have a number of shortcomings. For example, many conventional systems rely on domain-specific knowledge, such as customer habits regarding the purchase of movies. This places a great burden on the creator of the system to discover such knowledge and to design a custom recommendation system based on that knowledge, and does not permit an administrator to define corpora (i.e., distinct sets of documents) in a straightforward manner. Other conventional systems, such as many of those oriented towards retail sales, use social networking techniques (e.g., collaborative filtering), which rely on data about the interactions of other users with the various documents to infer the documents in which a particular user would be interested. However, the effectiveness of this technique is a function of the amount of the data on the interactions of other users, and thus systems with a small corpus or few users may not be able to beneficially employ social networking techniques.
SUMMARY
[0004] Disclosed is a system and method for providing recommendations of documents to a user of a document corpus—i.e., a particular collection of documents, such as those relating to technical talks, books on science, and the like. In some organizational environments, there can be a number of distinct corpora, and each is administrable by a corpus administrator. In one embodiment, the corpora are further grouped according to a domain to which they belong. The present invention is of particular applicability where the number of documents and users of a given corpus is sufficiently small to be managed by a corpus administrator, or where there are a number of distinct corpora with which users of a single organization interact differently. These are scenarios in which conventional recommendation systems have low utility.
[0005] In one embodiment, document features are extracted and assigned weights, and a profile is likewise created for the various users. Then, the documents are scored with respect to a given user based at least in part on the document features and the user's profile. The document scores are adjusted based on organization-specific information to reflect organizational goals, such as promoting recommendation of newer documents. Based on the scores, recommendations are determined for a given user by identifying the top scores for that user and the recommendations presented to the user. In one embodiment, recommendations are provided within a web-based user interface; in another they are provided via email; in another they are provided as an RSS feed; in still another they are provided as gadgets or frames embedded within other applications. Interactions of the users with recommendations are monitored and the recommendations updated accordingly.
[0006] In one embodiment, a computer-implemented method presents to a user selected portions of an organization's corpora, the corpora comprising documents, the method being carried out by a processor configured to determine a set of weighted terms for each of a plurality of the documents, to construct a user profile including user interest areas, to calculate a score for each of the plurality of the documents based on correlation between the weighted terms and the user profile, to adjust the calculated scores based at least in part on rules specified by the organization, and to present the adjusted and scored items to the user.
[0007] The features and advantages described in the specification are not all inclusive and, in particular, many additional features and advantages will be apparent to one of ordinary skill in the art in view of the drawings, specification, and claims. Moreover, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes, and may not have been selected to delineate or circumscribe the inventive subject matter.
BRIEF DESCRIPTION OF DRAWINGS
[0008] These and other features of the invention's embodiments are more fully described below. Reference is made throughout the description to the accompanying drawings, in which:
[0009] FIG. 1 is a high-level block diagram illustrating a recommendation system for providing recommendations as described herein.
[0010] FIG. 2 illustrates in more detail the components of the recommendation logic processor 115 of FIG. 1 .
[0011] FIG. 3 is a flowchart illustrating the process of providing recommendations, according to one embodiment.
[0012] FIG. 4 illustrates a user interface for displaying and interacting with recommendations.
[0013] FIGS. 5A-D illustrate user interfaces for administration of various aspects of the recommendation system 110 of FIG. 1 .
[0014] FIG. 6 illustrates a general purpose computer for use in implementing recommendation logic processor 115 of FIG. 1 .
DETAILED DESCRIPTION
System Architecture
[0015] FIG. 1 is a high-level block diagram illustrating a recommendation system 110 for providing the recommendations described herein. Also illustrated are a client computer system 120 used to interact with and/or receive recommendations from the recommendation system 110 , as well as a network 150 facilitating communications between the client 120 and the recommendation system 110 .
[0016] The recommendation system 110 comprises a corpus definitions database 111 , which defines each corpus in the system. In one embodiment, a corpus has a name, a set of associated documents, and (optionally) a set of associated users. As used herein, a “document” is a digital representation of information. A word processing file is a common example, but documents include many other things as well, such as digital representations of calendared events (e.g. a talk scheduled for a particular place at a particular time). The associated documents need not be stored on the recommendation system 110 itself; rather, in one embodiment only identifiers (e.g., URLs, path and file names) of the documents themselves need be stored—the data for the documents can be stored on the recommendation system 110 , on systems available on a network (e.g., 150 ) that is local to the recommendation system 110 , or on a remote system. In one embodiment, the associated users are represented by identifiers, such as operating system user IDs, of users interested in documents pertaining to that particular corpus. The documents for a given corpus need not be all of the same operating system file type, e.g. a text file or presentation file for a particular presentation application software, but rather can represent the conceptual category of the corpus. For example, in an exemplary embodiment one corpus is named “Technical Presentations,” has a set of 20 associated technical presentations in formats such as ADOBE PDF, Microsoft PowerPoint, word processing formats, event announcements and the like, and has two hundred associated users.
[0017] In one embodiment, the corpora are further grouped into domains. For example, an organization administering the recommendation system 110 creates individual domains for each organization that wishes to obtain its own personalized access to the recommendation system 110 . The implementation for this embodiment is similar to that described above, with the addition of an association between a corpus and a domain.
[0018] A document features repository 112 stores a set of features for each document of the various corpora defined by corpus definitions repository 111 . Features of a document represent its concepts, and in one embodiment consist of words and multi-word phrases (“n-grams”). In one example, a document on fishing has associated with it in the features repository 112 the set of terms “salmon”, “fly”, “reel”, “rod”, and “fishing vessel”, with each having an associated value (also referred to as a “weight”) quantifying how relevant the term is to the document. Features of a document could be present in the document itself, could be derived from a user-specified label, or could represent a category to which the document was assigned (e.g. “technical presentations”), for example. In one embodiment, the terms are chosen from a discrete set of possible terms, such as a set of 50,000 terms known to be useful in characterizing a document for search and recommendation purposes. As with other data storage repositories described below, the document features repository 112 is implemented in a conventional manner, such as a table of a conventional relational database management system, a text file, or a specialized binary file. Other manners of implementing repository 112 will be known to one of skill in the art.
[0019] A profile features repository 113 stores features, such as terms, associated with users. In one embodiment, each user has an associated profile, the profile storing terms chosen from the same set of possible terms as for the document features repository. The terms represent the interest areas of the user, each having an associated weight quantifying the relevance of the term to the user. As described further below, the terms and their weightings are derived from sources such as documents associated with the user, areas of interest explicitly entered by the user, and user interactions with recommended documents.
[0020] A document scores repository 114 stores scores for the various documents identified in the corpus definitions repository 111 , each score quantifying the relevance of a given document to a given user. In one embodiment, the score is calculated based at least in part on a function of a profile for the user and the document features for the document.
[0021] Recommendation logic processor 115 , as described further below, is a subsystem that determines which documents are most relevant to a given user, and provides a list of the recommended documents to the user.
[0022] A corpora management interface 116 provides a user interface allowing administration of corpora. A root user interface allows a root administrator responsible for administration of the recommendation system 110 as a whole to perform tasks such as adding new domains, e.g. by specifying a new document type. A corpus administrator interface allows a corpus administrator to perform tasks such as adding new corpora (e.g., by specifying a new document type), specifying which documents should be included within the corpus, specifying when document features and scores should be calculated or recalculated, and the like. Such features are illustrated in more detail with respect to FIGS. 5A-5C .
[0023] A corpus recommendation user interface module 117 generates the user interface displaying and allowing interaction with the recommendations for a particular corpus. In one embodiment, the user interface is constructed using a browser-based scripting language such as JavaScript, which can be rendered within a conventional web browser, e.g. as a particular module added by a user to a web page.
[0024] FIG. 2 illustrates in more detail the conceptual components of the recommendation logic processor 115 of FIG. 1 . Referring now also to FIG. 6 , in an exemplary embodiment recommendation logic processor 115 is, along with other aspects of system 110 , implemented by programming a general purpose computer 600 . Illustrated are a processor 602 coupled to a bus 604 . Also coupled to the bus 604 are a memory 606 , a storage device 608 , a keyboard 610 , a graphics adapter 612 , a pointing device 614 , and a network adapter 616 . A display 618 is coupled to the graphics adapter 612 . The processor 602 is in one embodiment any general-purpose processor such as an INTEL x86 compatible-CPU. The memory 606 can be firmware, read-only memory (ROM), non-volatile random access memory (NVRAM), and/or RAM, which holds instructions and data used by the processor 602 . The memory 606 may be divided into pages by an operating system of the computer 600 , each page having attributes such as whether the page is readable, writable, or executable (i.e. contains executable instructions), or whether it was loaded from a file on the storage device 608 . The storage device 608 is, in one embodiment, a hard disk drive but can also be any other device capable of storing data, such as a writeable compact disk (CD) or DVD, a solid-state memory device, or other form of computer-readable storage medium. The storage device 608 stores files and other data structures used by the computer 600 .
[0025] Referring again back to FIG. 2 , a feature extraction module 210 parses documents, assigning features with weights, or scores, according to a weighting algorithm. In an exemplary embodiment, a conventional term-frequency/inverse document frequency (“tf/idf”) weighting algorithm is used, in which each possible term (e.g., the 50,000 useful terms referenced above) is located in the document, and the term's calculated weight is proportional to the number of times the term appears in the document and inversely proportional to the frequency of the word in the corpus. Further detail on document weighting and scoring is found, for example, in commonly owned U.S. Pat. No. 7,383,258 to Georges Harik and Noam Shazeer, entitled “Method and Apparatus for Characterizing Documents Based on Clusters of Related Words.”
[0026] In one embodiment, the features and weights extracted automatically by the weighting algorithm are supplemented by additional features and weights associated with the document, such as any tags that the user has associated with the document. The features and weights are then stored in the document features repository 112 in association with an identifier of the document from which they were extracted.
[0027] A profile construction module 220 populates the profile features repository 113 . In one embodiment, the profile construction module 220 creates an initial profile for a given user based on available data sources. One data source is directory information available within the organization having the domain or corpus of which the user is a member, such as Lightweight Directory Access Protocol (LDAP) information stored on the organization's directory servers, e.g. personnel data available within a company tracking attributes such as age, sex, department, and the like. Another data source is a set of particular non-directory documents associated with the user and stored within the organization, such as a resume of the user or other document indicative of the user's interest areas. Terms are extracted from the document and weighted using the algorithms described above.
[0028] Use of these data sources allows the organization to leverage existing information that it stores about the user to produce higher-quality profiles than are created for systems which lack such pre-existing data about the user. In another embodiment, the user explicitly indicates terms of interest, such as by specifying a set of keywords (e.g. “tennis”, “Victorian literature”, etc.). Such explicitly-indicated terms in one embodiment are then assigned a weight higher than the weight of any other non-explicitly-indicated terms, representing the high degree of utility of explicit interests. In one embodiment, the profile construction module 220 additionally updates a user's profile, e.g. based on interactions of the user with documents, such as viewing initially, viewing for some period of time, printing, saving, emailing, explicitly marking the document as favored or disfavored using a user interface, and the like. For example, if a user is provided with a set of recommended documents and views a document having given terms, the value of those terms within the user's profile within the profiles feature repository 113 can be increased by an appropriate amount. In one embodiment, the effect of an interaction on the value of terms within the profile may decrease over time as the interaction ages. In one embodiment, the particular interaction triggering the update of the profile term value leads to different profile update actions. In an example, viewing of the document leads to a lesser increase in the value than printing the document, an action that presumably indicates more serious interest on the part of the user than does viewing. As another example, marking a document as disfavored leads not merely to reducing the values in the user profile for the terms within the document, but also to removing that article, possibly permanently, from any recommendations later provided to that user.
[0029] A document score calculator 230 calculates a score for a given document with respect to a given user based on a correlation between the feature weights generated by the feature extraction module 210 and the profiles generated by the profile construction module 220 . In one embodiment, the correlation algorithm is a conventional cosine similarity algorithm, which calculates the cosine of e.g. tf-idf vectors of terms for the user's profile and for the document being scored. In another embodiment, the document scores are not calculated independently of each other, but rather influence each other. In one example, a document scoring algorithm is designed to spread knowledge throughout the organization by recommending every document of the corpus to at least one user of the corpus. Such an approach is useful for avoiding institutional knowledge gaps that can come to exist for reasons such as employee attrition. This algorithm addresses an optimization problem in which the goal is to maximize the standard correlation measure matches between users and documents and to minimize the overlap (or maximize the completeness) of the coverage of all the documents in the corpus by the employees. The scores are calculated with respect to all of the users of the corpus at once through conjugate gradient, Monte Carlo, or other optimization techniques. In some embodiments, a number of algorithms are available, and the choice of which particular algorithm to use for a given corpus is made by the corpus administrator via the corpora management interface 116 . The document scores are then stored in the document scores repository 114 in association with an identifier of the user and the document to which they correspond.
Method of Operation
[0030] FIG. 3 is a flowchart illustrating the process of providing recommendations, according to one embodiment. At step 310 , document features of documents in the corpus are weighted, such as by the feature extraction module 210 . As discussed above, this entails, for each document, assigning weights, or scores, to the document features according to a weighting algorithm. One conventional weighting algorithm is term-frequency/inverse document frequency (“tf/idf”). In one embodiment, the features and weights extracted automatically by the above algorithms are supplemented by additional features and weights associated with the document, such as user-defined tags. The features and weights are then stored in the document features repository 112 .
[0031] At step 320 , which may be performed before, in parallel with, or after step 310 , an initial profile is created for a user, as described above with respect to the profile construction module of FIG. 2 .
[0032] At step 330 , documents from corpora 130 are scored by the document score calculator 230 as described above with respect to FIG. 2 . In one embodiment the scoring is initiated manually, e.g. through a user interface provided by corpora management interface 116 ; in another embodiment scoring is initiated at scheduled intervals, such as through a Unix “cron” process or other form of scheduled task.
[0033] At step 340 , the document scores are adjusted as desired based on the current context and the document features. A number of different adjustment rules may be used, and in one embodiment are specified by the corpus administrator via the corpora management interface 150 . For example, one adjustment rule biases the score in favor of more recent documents, e.g. by calculating an amount of time between a date of the document (e.g., a creation or modification date) and a set date, increasing the score as a function of the calculated amount of time if the document date is after the set date, and decreasing it otherwise. Adjustment of scores based on document recency can also be accomplished via exponential decay according to a specified document half-life. Another rule biases the score based on the document type or the document itself, e.g. specifying a multiplier value for the score of documents of type “tech talk”, or for a specified “tech talk” document deemed (e.g., by the corpus administrator) to be of particular interest. Still another rule increases the weight of documents that are specific to a user's organization (e.g., company) and increases the weight yet further for documents that are specific to the department or unit of the organization in which the user works. Such rules can also be used to limit the number of results, e.g. through a specified maximum number of results or through a specified minimum score (i.e., a threshold).
[0034] At step 350 , recommendations for a particular user are determined by the recommendation provider module 240 , as described above. They are then provided to the user. In one example, the results are displayed within the user interface provided by the corpus recommendation UI, such as the corpus recommendation user interfaces discussed with respect to FIG. 4 , below. In another example, the recommendations are emailed to the user. In still another example, the recommendations are provided as an RSS feed and displayed within an RSS viewer whenever a new recommendation is added to the list.
[0035] At step 360 , the user's interactions with documents are monitored. As previously described, different interactions with a document could indicate an interest level of the user in the document, such as viewing, printing, emailing, saving, explicitly marking as favored or disfavored, and the like.
[0036] At step 370 , if the user interactions monitored at step 360 result in a modification of the user's profile, then the recommendations for that user are likewise updated.
[0037] FIG. 4 illustrates a user interface for displaying and interacting with recommendations. Displayed are user interfaces representing recommendations for four corpora, 401 A- 401 D. Each has a title 405 A and a set of recommended documents such as 410 A. Recommended document 410 has associated “thumbs up” and “thumbs down” icons which the user may select to indicate interest or lack of interest in the article, which are used to update the user profile as described above with respect to profile construction module 220 . Each also has an options bar, e.g., 425 A, which lists various options associated with the corpus. A corpus recommendation user interface 401 A also provides options such as RSS icon 420 A, which causes changes to recommendations to be delivered to a news reader of the subscriber via the RSS protocol.
[0038] A user interface such as that of FIG. 4 displays all of the corpus recommendation user interfaces 401 associated with a user. Alternatively, individual corpus recommendation user interfaces 401 can be individually embedded within other user interfaces. For example, a web site could support the use of such corpus recommendation user interfaces 401 by allowing a user to select one or more corpus recommendation user interfaces of interest to be embedded in a user's personal home page, for example, and subsequent accesses of that home page by the user could fetch the user interface from the corpus recommendation user interface module 117 of the recommendation system 110 .
[0039] FIGS. 5A-D illustrate user interfaces for administration of various aspects of the recommendation system 110 of FIG. 1 . FIG. 5A illustrates a user interface for a root administrator. User interface area 505 allows a root administrator using the interface to grant rights to the root domain to another user. User interface area 510 allows the root administrator to make a user an administrator of a given domain. That user will then have permissions to administer that domain as described in FIG. 5B , below. User interface area 515 allows the root administrator to create a new domain, and individual corpora can then be associated with that domain, e.g. by an administrator for the domain. Finally, user interface area 520 allows the root administrator to see a list of all the domains that have been created for the recommendation system 110 .
[0040] FIG. 5B illustrates a user interface for an administrator of one of the domains. User interface area 530 allows the domain administrator to add a new corpus to the domain, optionally specifying both a full name of the domain (e.g., “Network Security Forum”) and a short name (e.g., “Net. SF”) for use in areas of user interfaces of the recommendation system in which compact names are useful. User interface area 535 allows the domain administrator to grant corpus administration privileges to another user of the system for one of the corpora in the domain—in the illustrated example, the corpus named “Jobs.” User interface area 540 allows the domain administrator to make another user of the system an administrator of the same domain.
[0041] FIG. 5C illustrates a user interface for a domain administrator for setting the default attributes for any corpus in that domain. An equivalent interface is used by an administrator of a specific corpus to define behavior of the recommendation and presentation of the documents in the corpus. User interface area 540 allows the corpus administrator to specify Javascript code to define the user interface of the corpus recommendation as desired. For example, the corpus administrator could write code to add menu items, links, etc. to the user interface of the corpus recommendation user interface, such as the link bar 425 A of FIG. 4 . User interface area 555 allows the corpus administrator to specify Cascading Style Sheet (CSS) code to control visual aspects such as how the document link text is displayed (9 point Arial font in the illustrated example). User interface area 560 allows the corpus administrator to specify which scoring algorithms and score adjustment filters to employ when computing scores for documents in the corpus. User interface area 565 allows the corpus administrator to specify “stop words”, i.e., words that will be ignored when scoring the documents in the corpus. Finally, user interface area 570 allows the corpus administrator to specify attributes of the corpus, such as the algorithm used to weight document features (e.g., “KW” in this example, which refers to the tf-idf, or “keyword”, algorithm).
[0042] It is appreciated that methods carrying out the above-described steps need not include the exact steps, formulas, or algorithms disclosed above, nor need they be in the same precise order. Rather, variations on the scope and functionality of the individual steps, and on the order thereof, are possible while still accomplishing the aims of the present invention.
[0043] As used herein any reference to “one embodiment” or “an embodiment” means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.
[0044] As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Further, unless expressly stated to the contrary, “or” refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).
[0045] In addition, the words “a” or “an” are employed to describe elements and components of the invention. This is done merely for convenience and to give a general sense of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.
[0046] Certain aspects of the present invention include process steps and instructions described herein in the form of a method. It should be noted that the process steps and instructions of the present invention could be embodied in software, firmware or hardware, and when embodied in software, could be downloaded to reside on and be operated from different platforms used by real time network operating systems.
[0047] The present invention also relates to a system for performing the operations herein. This system may be specially constructed for the required purposes, or it may comprise a general-purpose computer selectively activated or reconfigured by a computer program stored on a computer readable medium that can be accessed by the computer. Such a computer program may be stored in a computer readable storage medium, such as, but is not limited to, any type of disk including floppy disks, optical disks, CD-ROMs, magnetic-optical disks, read-only memories (ROMs), random access memories (RAMs), EPROMs, EEPROMs, magnetic or optical cards, application specific integrated circuits (ASICs), or any type of media suitable for storing electronic instructions, and each coupled to a computer system bus. Furthermore, the computers referred to in the specification may include a single processor or may be architectures employing multiple processor designs for increased computing capability.
[0048] Upon reading this disclosure, those of skill in the art will appreciate that still additional alternative structural and functional designs are possible. Thus, while particular embodiments and applications have been illustrated and described, it is to be understood that the present invention is not limited to the precise construction and components disclosed herein and that various modifications, changes and variations which will be apparent to those skilled in the art may be made in the arrangement, operation and details of the method and apparatus of the present invention disclosed herein without departing from the spirit and scope of the invention as defined in the appended claims. | A system and method provides recommendations of documents to a user of a document corpus. Document features are extracted and assigned weights, and a profile is likewise created for users. Documents are scored with respect to a given user based at least in part on the document features and the user's profile. The document scores may be adjusted to reflect organizational goals, such as promoting recommendation of newer documents. Based on the scores, recommendations are determined for a given user by identifying the top scores for that user and presented to the user in one of a variety of manners, such as within a web-based user interface, or via email. Interactions of the users with recommendations may be monitored and the recommendations updated accordingly. | 6 |
CROSS-REFERENCES TO RELATED APPLICATIONS
This application claims the benefit of German patent application DE P 10104419.4 filed Feb. 1, 2001, herein incorporated by reference.
1. Field of the Invention
The invention is relative to a device for the radial attitude control of a rapidly rotating rotor, especially a spinning rotor, supported in a contactless manner.
2. Background of the Invention
Contactless, passive support bearings or contactless, active supports with regulators for attitude stabilization or damping of oscillations are known in a great variety of embodiments.
For example, German Patent Publication DE 33 23 648 A1 shows a magnetic support comprising an actuating mechanism with electromagnetic coils. The magnetic support comprises two bearing parts offset relative to one another along the direction of the axis of rotation of a rotor. Translatory deviations of the instantaneous position of the axis of rotation from an ideal position are to be determined for two directions perpendicular to one another and to the axis of rotation of the rotor and stabilized by the controlling of magnetic forces. In addition, tilting movements of the rotor about axes of rotation parallel to the two directions perpendicular to the axis of rotation are determined and a restoring moment generated about these axes, and switching means are further provided for damping the nutation frequency. The nutation of the rotor is damped thereby by cross-coupling branches. Since all attitudinal deviations are stabilized, there is a constant readjusting in the case of high rotor speeds and the actuating mechanism is highly controlled. This is disadvantageous as concerns the consumption of energy and the load on the control elements and causes limitation phenomena in the control of the actuating mechanism, such as, for example, in the amplifiers. In particular, an elevation of amplitude in the so-called D-component in regulators (for example, in PD controllers or regulators) results at high frequencies and at high speeds and thereby results in high amplitude values of the control voltage. As a consequence, the power requirement of such a control is high. When the rotor speed is accelerated, increased power is required only for a brief time, for example, for fractions of a second as the speed passes through a resonance frequency of the support system. High power is constantly necessary in such attitude controls at the high operating speeds of rapidly rotating rotors, such as, e.g., in the case of spinning rotors.
In order to achieve a certain quietness and to be able to operate with less power, it is known that the rotor can be allowed to rotate not about its geometric axis but rather about its axis through the center of gravity or about the axis of inertia. For example, German Patent Publication DE 26 58 668 A1 discloses a magnetic support for a rotor in which the disturbing influences stemming in particular from imbalances and dependent on the rotor speed are reduced by means of a suppression filter. To this end, the control circuit of the magnetic support comprises a filter device interposed between the sensor device and the control circuit for the signals supplied from the sensor device. The filter device is designed as a suppression device whose frequency is adjusted according to the speed of the rotor. The suppression filter filters out disturbances of the rotor attitude that occur periodically with the rotational frequency and that would bring about a constant readjusting of the rotor into the central attitude. To this end, adding circuits and a negative feedback circuit are used. However, great complexity is necessary for the described circuits, which results in a relative great susceptibility to interference in the entire circuit. Moreover, such filter circuits cause significant phase rotations and/or phase errors that are generally recognized as disadvantageous. These phase rotations or errors can amount to more than 90 degrees and can endanger the stability of the control circuit or else which must themselves be compensated for in an expensive manner. Due to the carried-out adjustment of the effect of the suppression filter to a certain rotational speed of the rotor the desired effect does not occur at rotary frequencies deviating from this adjustment.
German Patent Publication DE 31 20 691 A1 describes a magnetic support in which deviations from the geometry of the rotor are detected by a sensor device and stored in a data storage along with the corresponding particular angular position at the rotary motion of the rotor. The detection takes place in a rotor-specific manner and is carried out before the particular rotor is put in operation. The stored values remain preserved for the entire operating time of the rotor. The disturbance signals generated by the sensor device and those deriving from errors of geometry are superposed and thus compensated by means of a correction signal. Unfortunately, the use of such a device, especially in spinning rotors of a rotor spinning machine, has disadvantages. Spinning rotors are subject to wear that can necessitate the replacement of the particular spinning rotor. If necessary, spinning rotors are also replaced during a batch change as a function of the fibrous material or yarn used. Thus, the replacement of spinning rotors that is unavoidably repeated when using spinning rotors requires significant expense on account of repeated detection operations. Also, a rather large computer capacity must constantly be available in order to store the amounts of data and to continuously process them. Further, imbalances which are not traceable to detectable errors of geometry, such as imbalances due to inhomogeneity of the rotor material or due to trash that can adhere and collect in the area of the rotor groove of spinning rotors, are not compensated in the device described in German Patent Publication DE 31 20 691 A1.
SUMMARY OF THE INVENTION
The present invention seeks to address the problem of improving the attitude control of rotors which are supported in a contactless manner.
The invention addresses this problem by providing a sensor device for the continuous generation of rotor attitude signals and a control device for processing the rotor attitude signals. The control device includes a controller that outputs a rotary-frequency-dependent output resultant signal or correcting variable, generated from the rotor attitude signals, for controlling the actuating device. The resultant signal follows the rotary-frequent waveform of the controller output signal at frequencies below the resonance frequencies of the contactless support, while above these resonance frequencies the resultant signal increasingly follows the rotary-frequent waveform of the controller output signal only in the area of at least one of the two extreme values (i.e., the minimum and maximum values) of the waveform, whereby the amplitude of the resultant signal is distinctly smaller than the amplitude of the rotary-frequency-dependent controller output signal. Further, the resultant signal of the rotary-frequency-dependent oscillation maps superposed oscillations of the controller output signal that are low-frequency in comparison to it in a practically unchanged manner.
Such a control device permits, upon the occurrence of rather high oscillatory frequencies, the lowering of the oscillation amplitudes of the oscillation dependent on the rotary frequency with small phase errors at the same time as regards the relatively low resonance frequencies and therewith permits an advantageous reduction of the power consumption of the attitude control as well as increased quietness of the rotor without customary suppression filters and without the above-mentioned disadvantages of the state of the art. The small phase errors that occur thereby do not endanger the stability of the control and are tolerable. On the other hand, the phase rotation that can be produced by customary deep-pass filters is significantly greater.
The reduction of the amplitude of the rotary-frequency-dependent oscillation of the resultant signal relative to the amplitude of the rotary-frequency-dependent oscillation of the controller output signal is preferably brought about by limiting the rise of the curve of the resultant signal to a maximum amount outside of the areas in which the resultant signal follows the waveform of the controller output signal. The concept “follow” used here also includes the instance in which there is only a slight difference between the resultant signal and the waveform of the controller output signal. The limitation of the rise applies not just to the area in which the rise of the controller output signal is positive, but also the area in which the rise of the oscillation of the controller output signal is negative (that is, if the curve falls). In the latter case, the rise of the curve and the slope of the resulting waveform are likewise limited to the maximum amount. The maximum amount can therefore also be considered as an absolute amount. As long as the rise of the controller output signal is below the limitation, the resultant signal follows the controller output signal and the control corresponds completely to the control algorithm. In contrast thereto, in the case of higher-frequency, rotary-frequency-dependent oscillations of the control output signal in which the waveform of the controller output signal sharply rises or falls and the rise exceeds the limitation, a reduction in the amplitude occurs, in accordance with the invention, in the rotary-frequency-dependent oscillations of the resultant signal used to generate the actuator control signal for the actuating device. For example, the magnitude of a voltage or of a current can be used as signal magnitude or as a correcting variable. The distinct reduction of signal components with high frequency and high amplitude, such as, for example, the rotary-frequency-dependent oscillation components of the controller output signal in the resultant signal, opens the possibility of an expanded ability to control low-frequency disturbing influences, such as, for example, the nutation of a rotor, without having to fear an overloading, of, for example, the actuating elements. The amplitude- and phase error produced in the amplitude reduction of the rotary-frequency-dependent oscillation components remains so slight or negligible that no instability of the control can occur. The avoidance of an overload as well as the extant stability of the control increase the operational safety. The apparatus of the present invention can be flexibly used as regards the rotor speeds, and is not subject to any limitation in as far as the presence or maintenance of a predetermined speed is concerned.
The advantageous effect of the invention can be achieved in a relatively simple manner and with low expense if the area in which the limitation of the rise of the curve of the resultant signal is effective over a maximum amount begins at the extreme value and ends when the value of the controller output signal attains again the instantaneous value of the resultant signal.
In an advantageous embodiment the control device is set in such a manner that the width of the particular area in which the resultant signal follows the waveform of the controller output signal is determined as a function of the rotary frequency and outside of these areas the rise of the curve of the resultant signal is preferably zero.
In the case of relatively low-frequency oscillations, such as in the case of support resonance frequencies, the area in which the resultant signal follows the waveform of the controller output signal may extend over the entire waveform. In the case of frequencies so far above the support resonance frequencies that their damping cannot be adversely impacted, the other area, in which the limitation of the rise takes effect and the rise is therewith constant in this other area, also participates in the waveform of the resultant signal. As the rotary frequency rises, the amount of the other area is increased to the extent to which the amount of the first area drops. As a result of the fact that the resultant signal still follows the controller output signal in a periodically reoccurring fashion in at least one area, the resultant signal remains phase-locked to the particular rotary frequency. The phase is synchronized and a drifting off avoided.
In another preferred embodiment of the present invention, a processor may be utilized to determine the width and the position of the respective first area, in which the resultant signal follows the waveform of the controller output signal, and of the other area, in which the rise is limited. The same effect can be achieved at a low cost without the necessity of making computer capacity available by means of a suitable circuit.
In another preferred embodiment of the present invention, the direct current component of the signal can be decoupled in a simple manner with a capacitor connected in after the control device. The passage of the nutation frequency takes place without appreciable phase error and without appreciable phase shift. The nutation of the rotor, especially that of a spinning rotor, can thus be effectively damped.
The control device is preferably set so that the rotary frequency at which the waveform of the resultant signal follows the waveform of the controller output signal only in the area of one of the two extreme values is at least twice as high as the decisive resonance frequency of the contactless support. High speed frequencies and/or oscillation frequencies occur, if, for example, the rotor is a spinning rotor rotating at the operating speed. Low-frequency resonance oscillations of the support system operating in a contactless manner that are to be damped remain preserved practically unaffected, and these oscillations can be effectively stabilized or damped by the signal used as the correcting variable.
The control device is preferably set up for forming a new signal as the arithmetic average of two resultant signals. One resultant signal follows the waveform of the controller output signal only in the area of one of the two extreme values and the other resultant signal follows it only in the area of the other of the two extreme values, and the new signal formed from the arithmetic average is advantageously output as the actuating control signal to the actuating device. In this manner an improved smoothing of the signal used as the correcting variable can be achieved with a further resulting lowering of the power requirement of the rotor support control.
A quasi-symmetric circuit design having two branches, each of which includes at least one diode, a capacitor whose capacitance determines the maximum amount of the rise for the area in which the limitation is effective, a constant current source and a resistor, requires no great expenditure for construction or any computer capacities. A-D converters or D-A converters are not necessary with this circuit because the signal processing can take place in a totally analog manner. The range of the area in which the resultant signal follows the controller output signal is generated automatically as a function of the rotary frequency.
The amplitude-lowering effect of the device of the invention may be improved by using resistors in the circuit such that the currents flowing in the respective resistors are distinctly smaller than the currents flowing in its associated constant current source
If the contactless support is an active magnetic support, available actuating elements can be used.
The effect produced by the lowering of the amplitudes corresponds to a so-called imbalance suppression. If the rotor rotates on its axis of inertia or its axis of gravitation, no continuous readjusting with high controlling of the actuating elements takes place. The power required for attitude control is relatively low. The device of the invention constitutes a simple, very economical and energy-saving but very effective means for attitude control and for active damping when passing through the support resonance frequencies and particularly in the nutation of rotors supported in a contactless manner. The device of the invention can achieve, in addition to the low consumption of energy, an expanded ability to control and greater operational safety in radial support controls of a rapidly rotating rotor supported in a contactless manner, especially of a spinning rotor.
Further details of the invention will be understood from the following description of an exemplary embodiment with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of a magnetic support of a spinning rotor.
FIG. 2 is a schematic view of a circuit for limiting the rise of a resultant signal in accordance with the present invention.
FIG. 3 is graphical illustration of a simplified waveform of the voltage on a capacitor of the circuit of FIG. 2 .
FIG. 4 is a graphical illustration of a simplified waveform of the voltage on another capacitor of the circuit of FIG. 2 .
FIG. 5 is a graphical illustration of an input waveform as well as the signals resulting from it.
FIG. 6 is a graphical illustration of a waveform representing the attitude of a spinning rotor rotating at a high speed.
FIG. 7 is a simplified graphical illustration of waveforms that result from the waveform shown in FIG. 6 .
FIG. 8 is a graphical illustration of the waveform of a resultant signal whose area-by-area rise is zero.
FIG. 9 is a schematic view of a control device with downstream capacitors, in accordance with an alternative embodiment of the present invention.
FIG. 10 is a schematic view of a control device with downstream capacitors in accordance with a further alternative embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the accompanying drawings and initially to FIG. 1, a spinning rotor 1 is held on a rotor shaft 2 by a magnetic support 3 . The position or attitude of rotor shaft is detected in a known manner by a sensor device comprising sensors 4 , 5 . The sensor device continuously generates detector signals and supplies them to a control device 6 , which outputs corresponding actuating signals. Actuating elements 7 , 8 , 9 , 10 associated with the sensors 4 , 5 comprise magnetic coils and serve to maintain the desired attitude of spinning rotor 1 . A drive device 11 imparts rotary movement to the spinning rotor 1 . The actuating device is loaded with control voltage U ST in order to actuate actuating elements 7 , 8 , 9 , 10 from control device 6 . Other sensors and actuating elements that act in a corresponding manner, not shown for reasons of simplicity, are arranged staggered by 90 degrees in the direction of rotation of spinning rotor 1 to sensors 4 , 5 and to actuating elements 7 , 8 , 9 , 10 . The actuating device is also loaded in the previously described manner from the control device 6 with an actuating control signal in the form of a control voltage U ST for these actuating elements.
In order to generate the particular control voltage U ST , the control device 6 comprises a regulator with a very extensive D component and also comprises a circuit 12 , shown in FIG. 2, which follows the regulator in the current path to the actuating device and to the particular actuating elements 7 , 8 , 9 , 10 .
A voltage U E is supplied on a voltage input 13 of the circuit 12 as the controller output signal of the PD regulator. Two parallel current paths 14 , 15 run out from the voltage input 13 . A diode 16 disposed in the course of one current path 14 allows current through when the voltage U E on voltage input 13 is positive relative to the instantaneous value on a capacitor 22 . The diode 16 acts like a switch. A constant current source 18 is connected to the output of the diode 16 and also to a constant negative voltage source 20 . The negative voltage source 20 of the exemplary embodiment of FIG. 2 supplies a voltage of, for example, minus 10 volts. The constant current source 18 comprises in a known manner a transistor whose base is supplied by a voltage that is constant in the example and comprises an emitter resistor. The capacitor 22 is disposed between the output of the diode 16 and ground 26 and a resistor 24 is disposed between the output of the diode 16 and a voltage output 27 .
A second current path 15 is designed quasi symmetrically to the first current path 14 . A diode 17 allows current through when a voltage U E that is negative relative to the instantaneous value on a capacitor 23 is on voltage input 13 . A constant current source 19 is connected to the output of the diode 17 and also to a constant positive voltage source 21 . The positive voltage source 21 supplies a voltage of, for example, plus 10 volts. The capacitor 23 is disposed between the output of the diode 17 and ground 26 and a resistor 25 is disposed between the output of the diode 17 and the voltage output 27 .
The threshold of each of the diodes 16 , 17 is approximately 0.6 volts in the exemplary embodiment. The capacitors 22 , 23 and resistors 24 , 25 are designed to be correspondingly equally large. The resistors 24 , 25 are dimensioned in such a manner that the currents flowing in the respective resistors 24 , 25 are distinctly smaller than the currents flowing in the associated constant current sources 18 , 19 .
In an alternative embodiment (not shown) of the circuit, the constant current sources 18 , 19 can be designed only as resistors for the sake of simplicity.
The mode of operation of the circuit 12 is explained in the following. A controller output signal of the PD regulator of control device 6 that has a positive voltage results, via voltage input 13 and diode 16 , in a positive voltage across the capacitor 22 . In contrast, a controller output signal that is negative results, via diode 17 , in a negative voltage across the capacitor 23 . Conditioned by the feeding of constant currents from the constant current sources 18 , 19 , the capacitor voltage on capacitor 22 corresponds to the voltage U E minus the threshold voltage of diode 16 . Similarly, the capacitor voltage on capacitor 23 corresponds to the voltage U E plus the threshold voltage of diode 17 . A voltage at the same level as voltage U E is again adjusted via resistors 24 , 25 acting as voltage dividers on voltage output 27 as output voltage U A , that is, voltage U E is an alternating voltage with low frequency and low amplitude; voltage U E and voltage U A continue to remain substantially equal.
If the rise of the oscillation representing the rotor attitude and the controller output signals exceeds, independently of frequency and amplitude, a particular maximum value, the waveform of the voltage 28 on the capacitor 22 is shown in the schematic view of FIG. 3 and the waveform of the voltage 29 on the capacitor 23 is shown in the schematic view of FIG. 4 . As a result, a significantly smaller amplitude is adjusted on the voltage output 27 for voltage U A than for the voltage U E . The voltage waveforms on the capacitors 22 , 23 occur when the rise (dU/dt) of the voltage waveform on the voltage input 13 over a time axis is greater than the rise of the voltage waveforms on the capacitors 22 , 23 . The amount of the rise of the voltage waveform on the capacitors 22 , 23 and therewith the maximum amount of the particular positive or negative rise is determined by the level of the current flow maintained by the constant current sources 18 , 19 and by the capacitance value of the capacitors 22 , 23 . The actuating control signal is derived from this voltage. For example, the rotary frequency of the spinning rotor 1 can be approximately 2 kHz, and the speed of the spinning rotor 1 approximately 120,000 rpm.
If the voltage input 13 is additionally loaded or superposed with a voltage U E ′ formed as a low-frequency alternating voltage this low-frequency alternating voltage is largely unchanged on the voltage output 27 in contrast to the alternating voltage derived from high-frequency signals. A slow nutational movement of the spinning rotor 1 that is detected, for example, by the evaluation of the rotor attitude signals as a low-frequency oscillation, can be optimally damped therewith. Thus, the energy consumption required for the attitude control of spinning rotor 1 may be kept low, and an overloading of the actuating elements 7 , 8 , 9 , 10 and of the amplifiers feeding the actuators may be prevented.
FIG. 5 shows by way of example the controller output signal represented as a voltage waveform denoted by reference numeral 30 . The waveform is a function of the rotor speed and of the attitude of the spinning rotor 1 and represents controller output signals. A first resultant signal 32 is derived from the voltage on the capacitor 22 in the area of amplitude maximums 31 in a manner in accordance with the invention. In a first section, the rising area 33 of the curve of the first resultant signal 32 largely follows the waveform of the controller output signal 30 until the amplitude maximum 31 . On the other hand, if the rise of the waveform of the controller output signal 30 exceeds a predetermined value in the falling area 34 after the amplitude maximum 31 or if the negative value there exceeds this predetermined value, the curve of the first resultant signal 32 runs in its falling area 35 as a straight line with a rise or a fall corresponding to this predetermined value. The curve of the first resultant signal 32 in its falling, straight-line area 35 represents the discharge of the capacitor 22 . When the curve of the controller output signal 30 crosses the curve of the first resultant signal 32 at an intersection 36 (that is, if the voltage U E represented by the curve of controller output signal 30 exceeds the voltage of capacitor 22 ), the discharge process of the capacitor 22 is ended and the capacitor 22 recharged. Accordingly, the curve of the first resultant signal 32 largely follows the waveform of the controller output signal 30 again as of the intersection 36 , and a new cycle begins.
A second resultant signal 37 is formed in the area of amplitude minimums 38 . The curve of the second resultant signal 37 largely follows the waveform of the controller output signal 30 until the amplitude minimum 38 in a first area 39 in which it falls or the rise is negative. On the other hand, if the rise of the waveform of the controller output signal 30 exceeds a predetermined value after the amplitude minimum 38 in area 40 , the curve of the second resultant signal 37 runs in its rising area 41 as a straight line with a rise corresponding to this predetermined value.
In its rising, straight-line area 41 , the curve of the second resultant signal 37 represents a discharge of the capacitor 22 . When the curve of the second resultant signal 37 crosses the curve of the controller output signal 30 at an intersection 42 , the curve of the second resultant signal accordingly largely follows the waveform of the controller output signal 30 again as of the intersection 42 , and a new cycle begins.
The slight differences between the waveform of the controller output signal 30 and the waveform of the first resultant signal 32 in the area of amplitude maximums 31 , and between the waveform of the controller output signal 30 and the waveform of the second resultant signal 37 in the area of amplitude minimums 38 , result from the diode threshold values of the diodes 16 , 17 . These slight differences are negligibly small.
Each of the two resultant signals 32 , 37 could be used by itself for attitude control or for damping. If, however, a new signal 43 is formed from an arithmetic average of the two resultant signals 32 , 37 , the amplitude of the new signal 43 can be reduced in comparison to the amplitudes of the two resultant signals 32 , 27 and the waveform of the new signal 43 can be smoothed. A further savings of energy can be achieved with a smoothing of the waveform of the new signal 43 .
FIG. 6 shows another voltage waveform 44 representative of control output signals. Like the one in FIG. 5, this waveform is also a function of the rotor speed and of the attitude of spinning rotor 1 and represents controller output signals. In the view of FIG. 6, a low-frequency oscillation, such as the one produced by a relatively slow nutational movement of a spinning rotor 1 , is superposed on the high-frequency oscillation dependent on the rotor speed. The waveform of this low-frequency oscillation is readily recognizable and made clearer by the course of a line 46 formed tangentially to the amplitude maximums 45 of the controller output signal 44 and by the course of a line 48 formed tangentially to the amplitude minimums 47 of the controller output signal 44 .
A new signal 49 with the waveform shown in FIG. 7 forms in the same manner as was explained using FIG. 5 upon a limitation of the rise from the waveform of curve 44 in falling areas 50 following the amplitude maximums 45 . Similarly, the waveform of a new signal 51 forms in a corresponding manner upon a limitation of the rise from the waveform of curve 44 in the rising areas 52 following the amplitude minimums 47 .
It should be noted that in the simplified view of FIG. 7, the amplitude maximums of the waveform of the resultant signal 49 and the amplitude minimums of the waveform of the resultant signal 51 are shown as angular “peaks.” In actuality, the amplitude maximums of the waveform of resultant signal 49 and the amplitude minimums of the waveform of resultant signal 51 do not run in the form of a peak, but rather are rounded off like the amplitude maximums 45 and the amplitude minimums 47 of the waveform of the controller output signal 44 .
If both resultant signals 49 , 51 are combined and an arithmetic average formed from them, a new signal 53 is produced from which the correcting variable may be derived. The formation of the new signal 53 , shown in idealized form, can take place with the aid of voltage dividers or resistors or by a computer.
The same low-frequency oscillation is mapped with the waveform of the new signal 53 as with the waveform of the control output signal 44 , but the amplitude of the waveform of the new signal 53 is distinctly smaller than the amplitude of the waveform 44 . Thus, the new signal 53 is considerably more suited as a correcting variable for the attitude control than the controller output signals from which the waveform 44 is derived. The lowering of the amplitudes takes place at relatively small phase error or at a phase error that is close to zero and is tolerable.
A circuit 12 which is flexibly designed as regards the rotor speeds permits effective attitude control and damping to be carried out in a simple and energy-saving manner.
Like FIG. 5, FIG. 8 shows a waveform representative of the controller output signal 30 . A resultant signal 59 follows the curve of controller output signal 30 to a first point 60 . The rise of the resultant signal 59 in section 62 is zero between the first point 60 and a second point 63 . After the second point 63 , the curve of the resultant signal 59 again follows the curve of controller output signal 30 in the area of the amplitude maximum 31 , and a new cycle begins. The resultant signal 59 may be generated from controller output signals 30 by a processor that is a component of the control device 6 . The particular position of the first point 60 and of the second point 63 in the cycles may be determined as a function of the frequency. Alternatively, a signal corresponding to the resultant signal 59 can also be generated with inclusion of the amplitude minimums 38 instead of the amplitude maximums 31 .
FIGS. 9 and 10 show alternative embodiments of the present invention in which at least one capacitor is arranged after the control device 6 in order to decouple the direct current component of the signal. FIG. 9 shows capacitors 54 , 55 , 56 , 57 connected in series between the control device 6 and the actuators 7 , 8 , 9 , 10 . In another embodiment, the respective capacitors can also be arranged inside the control device 6 (not shown).
FIG. 10 shows a further embodiment in which a single capacitor 58 is disposed after all of the actuators 7 , 8 , 9 , 10 . The decoupling of the direct current component, in particular in the case of an asymmetric signal waveform, results in a shifting of the signal average to the zero point. The actuators 7 , 8 , 9 , 10 are relieved by the decoupling of the direct current component.
It will therefore be readily understood by those persons skilled in the art that the present invention is susceptible of broad utility and application. Many embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications and equivalent arrangements, will be apparent from or reasonably suggested by the present invention and the foregoing description thereof, without departing from the substance or scope of the present invention. Accordingly, while the present invention has been described herein in detail in relation to its preferred embodiment, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for purposes of providing a full and enabling disclosure of the invention. The foregoing disclosure is not intended or to be construed to limit the present invention or otherwise to exclude any such other embodiments, adaptations, variations, modifications and equivalent arrangements, the present invention being limited only by the claims appended hereto and the equivalents thereof. | A device for the attitude control of a rapidly rotating rotor, especially a spinning rotor, supported in a contactless manner. The device comprises a sensor device for the continuous generation of rotor attitude signals and a control device ( 6 ) that processes the rotor attitude signals and continuously outputs a correcting variable to an actuating device that influences the rotor attitude. The control device ( 6 ) is set up in such that the rise of the waveform of a resultant signal from which the correcting variable is derived is limited to a maximum amount and, upon the occurrence of higher oscillation frequencies of the rotor attitude signals, the oscillation amplitudes of the resultant signal for the actuating device can at the same time be reduced with a small phase error. The device makes it possible to achieve low energy consumption, an expanded controllability and greater operational safety in a simple manner. | 5 |
PRIORITY
[0001] This application claims priority under 35 U.S.C. §119 of a Korean patent application filed on May 4, 2012 in the Korean Intellectual Property Office and assigned Serial No. 10-2012-0047612, the entire disclosure of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an analog amplifier and analog filter for amplifying an analog signal. More particularly, the present invention relates to an amplifier and filter having a cutoff frequency controlled according to a digital control code.
[0004] 2. Description of the Related Art
[0005] FIG. 1 illustrates a configuration of an analog filter according to the related art.
[0006] Referring to FIG. 1 , an analog filter is configured by combining a plurality of filter stages 100 of a first or higher order. A high-pass feedback stage 110 is connected between a first amplifier stage and an (n−1)th amplifier stage, and removes a noise included in a Direct Current (DC) component and a DC offset.
[0007] Each of the filter stages 100 includes an operational amplifier, a variable resistor, and a variable capacitor, and the gain and cutoff frequency thereof are controlled by the variable resistor and the variable capacitor. That is, the gain of each filter stage 100 is determined by a ratio of an input resistance to a feedback resistance, and the cutoff frequency is inversely proportional to a product of a feedback resistance and a feedback capacitance.
[0008] The variable resistor of each filter stage 100 may include two or more segments each configured by combining short switches and a plurality of resistors, and the short switches are controlled by a digital code. The digitally controlled serial resistor connection has a binary structure in which the number of resistors increases, such as 2R, 4R, 8R, 16R, . . . , 2nR (where n is an integer), and the total resistance is linearly proportional to the digital code. The resistance of the variable resistors varies linearly according to the digital code K, and the cutoff frequency is proportional to a reciprocal of the resistance.
[0009] Alternatively, the variable capacitor of each filter stage 100 may include two or more capacitor segments each configured by combining short switches and capacitors in order to variably change the cutoff frequency, and the short switches may be controlled by a digital code. For example, the digitally controlled parallel capacitor connection has a binary structure in which the number of the capacitors increases, such as 2C, 4C, 8C, 16C, . . . , 2nC, and the total capacitance of the capacitors is linearly proportional to the digital code. The total capacitance of the variable capacitors varies linearly according to the digital code K, and the cutoff frequency is proportional to the reciprocal of the capacitance.
[0010] Generally, a frequency axis is represented on a logarithmic scale in the frequency domain, and a decibel (dB) unit representing a gain has a logarithmic scale value. Accordingly, a variable resistance or capacitance, which varies linearly according to the digital code K, has nonlinear characteristics, and thus reduces efficiency.
[0011] That is, as the value of the digital code K increases, the variable resistance or capacitance varies rapidly on the logarithmic scale, whereas as the value of the digital code K increases, the variable resistance or capacitance varies slowly on the logarithmic scale. This reduces the accuracy of the variable resistance or capacitance upon operation at high frequency bands as illustrated in FIG. 2 , causing uncontrollable intervals as well as the reduction of efficiency.
[0012] FIG. 2 is a graph illustrating a relation between a frequency and a gain according the related art.
[0013] As the value of the digital code K increases, the variable resistance or capacitance varies slowly on the logarithmic scale, whereas as the value of the digital code K increases, the variable resistance or capacitance varies rapidly on the logarithmic scale, causing intervals in which the cutoff frequency is uncontrollable.
[0014] Also, when the frequency change widths of respective digital codes are measured, the change widths are inconsistent due to quantization errors of respective change intervals as illustrated in FIG. 3 , so that uncontrollable intervals occur even though the frequency axis is considered linearly rather than on the logarithmic scale.
[0015] FIG. 3 is a graph illustrating a relation between a digital control code and a frequency according the related art.
[0016] Accordingly, there is a need for a filter and amplifier having a cutoff frequency conveniently controlled exponentially according to a digital code.
[0017] The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present invention.
SUMMARY OF THE INVENTION
[0018] Aspects of the present invention are to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide a variable cutoff frequency filter circuit, the cutoff frequency of which can be finely defined even at a high frequency band which is frequently used.
[0019] Another aspect of the present invention is to provide an analog circuit that can be intuitively understood by a user that is accustomed to the processing of the log value of a cutoff frequency.
[0020] Yet another aspect of the present invention is to provide a variable capacitor circuit, the total capacitance of which increases exponentially as the value of a control code increases.
[0021] In accordance with an aspect of the present invention, an amplifier circuit is provided. The amplifier circuit includes an operational amplifier, a feedback resistor for changing gain and cutoff frequency characteristics of the operational amplifier, and a feedback variable capacitor for changing the cutoff frequency characteristics of the operational amplifier, wherein a capacitance of the feedback variable capacitor increases exponentially according to a digital control code, and the cutoff frequency of the operational amplifier is inversely proportional to the capacitance of the feedback variable capacitor and varies linearly on a logarithmic scale.
[0022] In accordance with another aspect of the present invention, an amplifier circuit is provided. The amplifier circuit includes a logic circuit for performing logic operations on a digital control code, a feedback capacitor having a capacitance varying according to a digital output signal of the logic circuit, and an operational amplifier having cutoff frequency characteristics inversely proportional to the capacitance of the feedback capacitor, wherein a cutoff frequency of the operational amplifier is inversely proportional to the capacitance of the feedback variable capacitor and varies linearly on a logarithmic scale.
[0023] Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The above and other aspects, features and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:
[0025] FIG. 1 illustrates a configuration of an analog filter according to the related art;
[0026] FIG. 2 is a graph illustrating a relation between a frequency and a gain according the related art;
[0027] FIG. 3 is a graph illustrating a relation between a digital control code and a frequency according the related art;
[0028] FIG. 4 is a circuit diagram illustrating an amplifier using a variable capacitor according to an exemplary embodiment of the present invention;
[0029] FIG. 5 is a circuit diagram illustrating a variable capacitor according to an exemplary embodiment of the present invention
[0030] FIG. 6 is a graph illustrating a relation between a frequency, a gain and a digital control code K according to an exemplary embodiment of the present invention.
[0031] Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0032] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.
[0033] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention is provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.
[0034] It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more of such surfaces.
[0035] Hereinafter, an apparatus and method are provided for implementing an amplifier and a filter having a cutoff frequency controlled exponentially according to a digital control code according to exemplary embodiments of the present invention.
[0036] FIG. 4 is a circuit diagram illustrating an amplifier using a variable capacitor according to an exemplary embodiment of the present invention.
[0037] Referring to FIG. 4 , an amplifier 400 may change a cutoff frequency by modifying a capacitance value of a feedback variable capacitor 410 . According to another exemplary embodiment, the amplifier 400 may change a gain value and a cutoff frequency by modifying resistance values of feedback variable resistor 420 and input variable resistor 430 . While each of the feedback variable capacitor 410 , the feedback variable resistor 420 , and the input variable resistor 430 are described herein as being variable, one or more of the feedback variable capacitor 410 , the feedback variable resistor 420 , and the input variable resistor 430 may be non-variable.
[0038] The gain value and the cutoff frequency value in the direct current of the amplifier are defined based on the following Equation (1):
[0000]
Gain
=
R
b
R
a
,
f
c
=
1
2
π
R
b
C
Equation
(
1
)
[0000] where R a is the resistance of the input variable resistor 430 , R b is the resistance of the feedback variable resistor 420 , and C is the capacitance of the feedback variable capacitor 410 .
[0039] According to the exemplary embodiments of the present invention, the following procedures are used to change the cutoff frequency on a logarithmic scale linearly (linear in dB) while obtaining a uniform gain value. The ideal capacitance value of the feedback variable capacitor 410 which allows for a desired cutoff frequency is calculated, and a value closest to an ideal capacitance value is calculated among values which can be provided by the feedback variable capacitor 410 and is set to C. A detailed structure of the feedback variable capacitor 410 will be described below with reference to FIG. 5 .
[0040] The ideal resistance value of the input variable resistor 430 which enables the gain value to be maintained uniformly is calculated, and a value closest to an ideal resistance value is calculated among values which can be provided by the input variable resistor 430 and is set to R a .
[0041] FIG. 5 illustrates a variable capacitor controlled exponentially according to an exemplary embodiment of the present invention.
[0042] Referring to FIG. 5 , the variable capacitor includes a plurality of capacitor segments, and switches for controlling the connection states of the parallel-connected capacitor segments. Here, while two switches are shown for each of the plurality of capacitor segments, one switch may alternately be employed.
[0043] For example, the capacitance of the variable capacitor is determined by a 3-bit control code (b 0 b 1 b 2 ). The variable capacitor includes a first capacitor segment including only a unit capacitor C, a second capacitor segment including a capacitor of 0.414C times and a first switch, a third capacitor segment including a unit capacitor and a second switch, a fourth capacitor segment including a capacitor of 0.414C times and a third switch, a fifth capacitor segment including a capacitor of 3C times and a fourth switch, a sixth capacitor segment including a capacitor of 1.242C times and a fifth switch, a seventh capacitor segment including a capacitor of 3C times and a sixth switch, and an eighth capacitor segment including a capacitor of 1.242C times and a seventh switch, which are connected in parallel.
[0044] Herein, the first switch is closed by the first bit (b 0 ) of the 3-bit digital code, the second switch is closed by the second bit (b 1 ) of the 3-bit digital code, and the fourth switch is closed by the third bit (b 2 ) of the 3-bit digital code. The third switch is closed by the result of AND operation of the first bit (b 0 ) and second bit (b 1 ) of the 3-bit digital code, the fifth switch is closed by the result of AND operation of the first bit (b 0 ) and third bit (b 2 ) of the 3-bit digital code, the sixth switch is closed by the result of AND operation of the second bit (b 1 ) and third bit (b 2 ) of the 3-bit digital code, and the seventh switch is closed by the result of AND operation of the first bit (b 0 ), second bit (b 1 ) and third bit (b 2 ) of the 3-bit digital code.
[0045] In general cases, with respect to the digital code k, the total capacitance is generalized by the following Equation (2):
[0000]
C
total
=
C
0
·
2
k
2
N
Z
Equation
(
2
)
[0000] where C 0 is the capacitance of a unit capacitor when the digital code is 0, N is the number of bits representing the digital code, and Z is a compression constant determining the capacitance difference between two digital codes. For example, the compression constant Z becomes Z=4 when the difference between the capacitance at the first digital code and the capacitance at the second digital code is determined as √{square root over (2)} times. Therefore, in order to implement a variable frequency filter, the capacitance of which increases in the unit (=3 dB unit) of √{square root over (2)} times using a 3-bit digital code, the capacitance values are respectively set to 0.414 times, 1 times, 0.414 times, 3 times, 1.242 times, 3 times, 1.242 times of the unit capacitor C.
[0046] In this exemplary embodiment of the present invention, N is set to 3 (N=3) and Z is set to 4 (Z=4).
[0047] When the input digital code is 0 (b 2 b 1 b 0 =000), the unit capacitor of the upper stage is only activated, so that the total capacitance becomes C. In this case, the first to seventh switches are all in the off state.
[0048] When the digital code is 1 (b 2 b 1 b 0 =001), connection is accomplished through the switch b 0 , so that the total capacitance becomes 1.414C (=C+0.414). In this case, only the first switch is turned on and the other switches are all turned off.
[0049] When the digital code is 2 (b 2 b 1 b 0 =010), the switch b 1 is turned on, so that the total capacitance becomes 2C (=C+C). In this case, only the second switch is turned on and the rest of the switches are all turned off.
[0050] When the digital code is 3 (b 2 b 1 b 0 =011), the switches b 0 and b 1 are all turned on, so that the total capacitance becomes 2.828C (=C+0.414C+C+0.414C). In this case, the first switch, second switch and third switch are turned on and the fourth to seventh switches are turned off. The third switch is switched according to the result of an AND operation of the first bit (b 0 ) and the second bit (b 1 ). For example, the third switch is turned on only when b 0 and b 1 are all 1.
[0051] When the digital code is 4 (b 2 b 1 b 0 =100), the switch b 2 is turned on, so that the total capacitance becomes 4C (=C+3C). In this case, only the fourth switch is turned on and the other switches are turned off.
[0052] When the digital code is 5 (b 2 b 1 b 0 =101), the switches b 0 and b 2 are turned on, so that the total capacitance becomes 5.656C (=C+0.414C+3C+1.242C). In this case, only the first and fourth switches are turned on and the other switches are turned off.
[0053] When the digital code is 6 (b 2 b 1 b 0 =110), the switches b 0 and b 2 are turned on, so that the total capacitance becomes 8C (=C+C+3C+3C). In this case, the second, fourth and sixth switches are turned on and the other switches are turned off. The sixth switch is switched according to the result of an AND operation of the second bit (b 1 ) and the third bit (b 2 ). For example, the sixth switch is turned on only when b 1 and b 2 are all 1.
[0054] When the digital code is 7 (b 2 b 1 b 0 =111), the switches are all turned on, so that the total capacitance becomes 11.314C (=C+0.414C+C+0.414C+3C+1.242C+3C+1.242C). In this case, the first to seventh switches are all turned on. In this case, the seventh switch is switched according to the result of an AND operation of the first bit (b 0 ), second bit (b 1 ) and the third bit (b 2 ). For example, the seventh switch is turned on only when b 0 , b 1 and b 2 are all 1.
[0055] In order to represent this relationship in an equation, when the total capacitance is developed in a Taylor series and b 2N =b are b 2 , b 1N =b 1 and b 0N =b 0 are applied thereto based on the understanding that b 2 , b 1 and b 0 are all 1 or 0, the relation can be expressed as Equation (3).
[0000]
C
total
=
C
×
2
KZ
/
2
N
=
C
×
2
(
4
×
b
2
+
2
×
b
1
+
b
0
)
Z
/
2
N
=
C
×
(
1
+
k
·
ln
2
·
Z
/
2
N
+
(
k
·
ln
2
·
Z
/
2
N
)
2
/
2
!
+
(
k
·
ln
2
·
Z
/
2
N
)
3
/
3
!
+
⋯
=
C
(
1
+
0.414
×
b
0
+
1
×
b
1
+
0.414
×
b
0
b
1
)
×
(
1
+
3
×
b
2
)
⋯
Equation
(
3
)
[0056] As in Equation (2), when a capacitor bank increases exponentially, the reciprocal of the square root of the capacitance of the capacitor bank has also exponential characteristics. As a result, in order to have linearity on the logarithmic scale, the capacitor bank increases and decreases exponentially according to the digital code.
[0057] Although the exemplary embodiments of the present invention have been described with respect to a case where the bit number of the digital control code is a 3-bit number, the bit number of the digital control code may be extended to N bits.
[0058] FIG. 6 is a graph illustrating a relation between a frequency, a gain and a digital control code K according to an exemplary embodiment of the present invention.
[0059] Referring to FIG. 6 , it can be seen that uniform intervals are maintained on the logarithmic scale by controlling a cutoff frequency and a gain exponentially according to the digital control code K. This enables fine control of the cutoff frequency, thus improving a filter performance as well as increasing system efficiency.
[0060] As described above, exemplary embodiments of the present invention provide a variable capacitor and a variable cutoff frequency filter circuit in which the cutoff frequency of the variable cutoff frequency filter can be finely defined, even at a high frequency band which is frequently used.
[0061] Also, exemplary embodiments of the present invention provide an analog circuit that can be intuitively understood by a user that is accustomed to the processing of the log value of a cutoff frequency.
[0062] Therefore, exemplary embodiments of the present invention can remove a complex logic circuit used to obtain an approximate value in the existing binary variable capacitor to simplify a digital control unit, which reduces a total circuit area to reduce a unit circuit cost, and reduce a noise generated in a digital logic circuit to thereby increase filter performance.
[0063] For this, exemplary embodiments of the present invention provide a variable capacitor circuit, the cutoff frequency of which decreases exponentially as the value of a control code increases.
[0064] While the invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents. | An amplifier circuit is provided. The amplifier circuit includes an operational amplifier, a feedback resistor for changing gain and cutoff frequency characteristics of the operational amplifier, and a feedback variable capacitor for changing the cutoff frequency characteristics of the operational amplifier, wherein a capacitance of the feedback variable capacitor increases exponentially according to a digital control code, and the cutoff frequency of the operational amplifier is inversely proportional to the capacitance of the feedback variable capacitor and varies linearly on a logarithmic scale. | 7 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a new and improved mail signal system. More particularly, the invention relates to providing a signal in the residence that mail has been deposited in a mailbox remote from the residence. Means is also provided for distinguishing between mail which has been deposited in the box as outgoing mail and new or incoming mail.
2. Description of Related Art
Various devices have been used to detect the presence of incoming mail. Thus, opening the door of the mailbox has actuated a signal in such references as U.S. Pat. Nos. 3,611,333 and 3,707,260.
The opening of the door admits light which affects the functioning of a photocell within the box in such references as U.S. Pat. Nos. 3,909,819 and 4,314,102, as well as Swiss Pat. No. 600,844.
The opening of a door may actuate a microswitch as in reference U.S. Pat. No. 4,314,102.
U.S. Pat. No. 2,968,804 discloses a device where mail in the box interferes with the signal in a transmitter and receiver in the box. In the present invention, however, the use of an optical reflective detector eliminates the remote receptor and, in addition, the transmission of the signal is improved over what is shown in in that reference.
SUMMARY OF THE INVENTION
A photodiode is located at the top of a mailbox. The presence of an envelope or other mail inside the box thus produces a signal because it interferes with receipt of the light from the photodiode by an infrared emitter. In one form of the invention such signal is transmitted at radio frequency to a receiver in the home tuned to the frequency of the transmitter. On reception of the signal from the transmitter, an indicator lamp is lit and, optionally, an audible signal is activated. The transmitter is preferably located externally on top of the box within a protective cover. The transmitter and cover are sealed by a rubber seal to weatherproof the contents of the box.
A problem with mail indicator systems is to distinguish between outgoing mail which is deposited in the box and incoming mail. Means are disclosed herein to distinguish between outgoing and incoming mail. One such means is to detect the opening of the box when the mail carrier removes the outgoing mail whereby the amount of light inside the box changes.
Other objects of the present invention will become apparent upon reading the following specification and referring to the accompanying drawing in which similar characters of reference represent corresponding parts in each of the several views.
In the drawings:
FIG. 1 is a perspective view of one form of the invention showing the mailbox door open;
FIG. 2 is a front elevation view thereof;
FIG. 3 is an enlarged fragmentary view of the cover for the r.f. transmitter;
FIG. 4 is a perspective view of a receiver located within a residence or an individual apartment or condominium;
FIG. 5 is a schematic block diagram of the system of FIG. 1-4;
FIG. 6 is a schematic of the optical sensing, logic and associated components;
FIG. 7 is a schematic of the r.f. receiver;
FIG. 8 is a block diagram showing use of the invention in an apartment house or condominium.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the form of the invention shown in FIGS. 1-3, a roadside type mail box 21 is supported above the ground by a stand 22. Although the shape of the box 21 is subject to considerable variation, it will be seen that it has a door 23 at one end for the deposit and withdrawal of mail. The main portion of the box has a bottom 24 which is preferably of a color such as not to reflect errant light. The sides and top 26 of the box are formed in conventional fashion. Placed within box 21 immediately below top 26 and adjacent the opening which is closed by door 23, are electronic components hereinafter described. The forward end of unit 27 is an outgoing mail switch 47 and contained therein is off-on switch 28. A radio frequency transmitter is employed in the present invention, the circuit board 31 for which is shown on the outside of the box 21 protected by a shell-like cover 32. An opening (not shown) is formed in the top 26 for communication between the circuit board 31 and the unit 27 and such opening is made weather tight by a seal pad 33 immediately below the cover 32 and held in place by screws 34 or other simple means.
FIG. 5 is a block diagram for the system, as hereinafter described.
A schematic for this system is shown in FIGS. 6 and 7 and hereinafter described.
Located in the residence is a radio frequency receiver 41 receiving the signal from transmitter 31. Receiver 41 has a visual "mail in" signal, or light 59, and a reset button 61. The schematic for receiver 41 is shown in FIG. 7 and hereinafter described.
As shown in the block diagram FIG. 5, once the optical system senses mail, it will trigger or activate the r.f. transmitter 31. A suitable frequency for the transmitter is in the 300 MHz range. The transmission system is similar to garage door openers.
Cover 32 protects the transmitter from the environment. The illustrated cover shape reduces as much as possible disturbance of the transmitter. The cover is designed so that servicing of the transmitter can be done by simply pulling the transmitter out of the housing. The cushioned seal pad 33 at the base of the housing is for weatherproofing the electronics below the housing. The screws 34 function not only to attach the cover to the box but also to connect the electronics.
The reception of the signal is performed by the r.f. receiver 41. Since digital coding is normally used, the receiver is also equipped to digitally decode the signal. Once accepted, the output normally momentary is latched on the additional electronics needed. The latch, of course, powers the "mail in" signal 42 indicator lamp. This lamp stays constantly on until reset switch 43 is pressed.
Directing attention now to the schematic of FIG. 6, when the door 23 is opened, the light admitted is detected by photodiode 36. The signal therefrom is amplified by an operational amplifier 271 No. 1. The output thereof is received by a programmable monostable one-shot multivibrator 37. This has a time delay of approximately one minute. It is connected so that the light signal received by diode 36 triggers it but, further, any additional impulses of light received by diode 36 extends the time duration thereof. Timer 37 is triggered on the falling edges so that the system is not triggered until the door 23 is closed. The purpose of timer 37 is to command the system to operate from a basically standby mode. After the timer 37 has timed out, a signal is directed to the No. 1 L555 which generates a very short (e.g. 30 ms) pulse to drive the transistor 2n3643, which in turn pulses the infrared diode emitter 38. The beam from the emitter 38 is directed to the bottom 24 of box 21 and reflected. Reflections are picked up by the receiving photodiode 39, the outgoing signal of which is amplified by operational amplifier 271 No. 2 which triggers the second L555 r.f. transmit timers, setting the r.f. transmitter to transmit a signal for approximately one to five seconds. The L555 No. 2 timer will not transmit on channel 1 if no signal is present (i.e. no mail is in the box) but instead, the signal is transmitted on channel 2. Channel 2 represents a reset channel.
If mail was previously in the box and the box is opened and the mail removed, reset channel 2 will automatically update the status of mail in the box. Reset channel 2 is initiated by a pulse command infrared pulse to L555 No. 1 timer, which is set for exactly the same time as the second L555 timer. The two signals then pass through the NOR gates and if no signal is received from the L555 No. 2, the signal from L555 No. 1 will then trigger the channel 2 transmitter.
By pushing the outgoing mail button 47, the one-shot 37 command is disabled and hence upon closing the box the status of the box is disabled and the outgoing mail may be inserted without a system error. When the outgoing mail is picked up, the status of the mail is automatically updated.
It should further be noted that when the customer picks up the mail from the box, it is unnecessary to reset the receiver since this is done automatically every time the box is opened.
To control a "mail in" indicator 59, a CMOS 4001 circuit is shown in FIG. 7. This functions as a latch so that channel 1 will latch the "mail in" indicator light LED 59 on continuously and channel 2 (or the manual reset switch) 61 will unlatch the LED "mail in" indicator 59. Optionally an audible tone beeper may be connected to cause a tone, if desired.
Directing attention now to FIG. 8, an apartment house or condominium multi-box unit 51 is shown having a plurality of mail slots 52 separated by partitions 53. Wiring into such a box may be difficult if there is concrete or if there is no access behind the box. Accordingly, each box is provided with a system similar to FIG. 6. This is received in a centralized reeeiving unit which discriminates between the different signals from each of the boxes. Such a signal is then transmitted through a carrier current such as a household lighting system to the individual apartment houses. Alternatively, a mail detection unit is connected to the individual mail boxes and the "mail in" information is stored in a centralized decode telephone computer. The resident then calls his or her telephone number and receives a recorded message of whether mail is present in the box or not.
The embodiments herein described and illustrated are designed for individual mailboxes 21 relatively isolated from other boxes. Directing attention to FIG. 8, the invention may be extended to condominium and apartments there is a central mailbox console 51 having a plurality of mail slots 52 separated by partitions 53. Because of the large number of boxes involved and the longer distances from the boxes to the living quarters, different means of transmission may be used. Rather than using r.f transmission, carrier current may be used (i.e., digital transmission along the 115 VAC household current lines). Each mailbox unit 52 has its own optical sensor similar to sensors 27 described in the preceding embodiments. Upon activation, the signal is sent to a master transmission unit by means of lines 56a, 56b, 56c, etc., respectively. In the box 57, coding for the individual units and transmission occurs. Such transmission is sent along the 115 VAC power lines in the 80-200 KHz range. Each condominium or apartment is equipped with a receiver and indicator unit shown in FIG. 7 and having a "mail in" signal 59 and a reset button 61. The receiver shown in FIG. 7 is of a "carrier current" type (rather than r.f.) with a suitable digital , decoding to differentiate between the several apartment units.
Alternatively, instead of using a carrier current, where the system is installed in a new building, direct wires from the sensors to the receivers 58 may be substituted. | A signal to indicate deposit of mail in a box remote from a residence employs an optical reflective detector which senses presence of mail in the box. The transmission may be r. f. if the box is relatively isolated from other boxes. In apartments, condominiums, and the like where multiple boxes are centrally located, transmission may be by special wiring or by imposing a coded signal on house electrical wiring. Means is provided for the detector distinguishing between outgoing mail deposited in the box and new incoming mail. | 0 |
REFERENCE TO PENDING PRIOR PATENT APPLICATIONS
[0001] This patent application claims benefit of:
[0002] (1) pending prior U.S. Provisional Patent Application Ser. No. 60/318,434, filed Sep. 10, 2001 by Richard Belle Isle et al. for REUSABLE SHIPPING PALLET FORMED FROM EXTRUDED PLASTIC PARTS WHICH ARE EASILY ASSEMBLED AND DISASSEMBLED (Attorney's Docket No. BELLE-2 PROV), which patent application is hereby incorporated herein by reference; and
[0003] (2) pending prior U.S. Provisional Patent Application Ser. No. 60/381,231, filed May 17, 2002 by Richard Belle Isle et al. for REUSABLE SHIPPING PALLET FORMED FROM EXTRUDED PLASTIC PARTS WHICH ARE EASILY ASSEMBLED AND DISASSEMBLED (Attorney's Docket No. BELLE-3 PROV), which patent application is hereby incorporated herein by reference.
FIELD OF THE INVENTION
[0004] This invention relates to shipping pallets in general, and more particularly to reusable shipping pallets formed from extruded plastic parts.
BACKGROUND OF THE INVENTION
[0005] In 1999, over four hundred million wooden pallets were produced for use in shipping freight.
[0006] While wooden pallets are relatively inexpensive to produce, they are also relatively heavy and bulky. As a result, where freight is being shipped in only one direction (e.g., from a manufacturer to a distributor), the wooden pallets are generally discarded after use, since it is uneconomical to return the empty pallets to their origin. However, disposal can present a problem, since many landfill areas are now refusing to accept discarded pallets because they are not compactable. Consequently, many discarded wooden pallets must be converted to mulch, which can present additional costs.
[0007] Furthermore, even where it is practical to reuse the wooden pallets, the wooden pallets themselves can present problems. By way of example, the wooden pallets are typically fastened together using metal hardware such as nails, screws, and bolts with nuts. This metal hardware can rust over time and may work its way into the product which is being carried by the pallet, thereby contaminating the shipment. In this respect it should be noted that approximately sixty percent of pallet usage occurs in the food and pharmaceutical industries, where such contamination can present serious health risks.
SUMMARY OF THE INVENTION
[0008] As a result, one object of the present invention is to provide a new form of pallet which is relatively inexpensive to produce.
[0009] Another object of the present invention is to provide a new form of pallet which is relatively lightweight and compact.
[0010] And another object of the present invention is to provide a new form of pallet which is reusable.
[0011] Still another object of the present invention is to provide a new form of pallet which is easily assembled at the point of shipment and easily disassembled at the point of destination.
[0012] Yet another object of the present invention is to provide a new form of pallet which is particularly compact in its disassembled form, whereby to facilitate transferring the pallet to another location for reuse.
[0013] These and other objects are addressed by the present invention, which comprises a reusable shipping pallet formed from extruded plastic parts which are easily assembled and disassembled.
[0014] In one form of the invention, there is provided a reusable shipping pallet formed from extruded plastic parts, the pallet comprising: at least two I-beam constructs, each of the I-beam constructs having a first beam end, a second beam end and a longitudinal beam axis extending therethrough, each of the I-beam constructs having a top beam portion and a bottom beam portion, and each of the I-beam constructs having a dovetail projection along the top beam portion and extending in a direction parallel to the longitudinal beam axis; and at least one deck board having a first board end, a second board end and a longitudinal board axis extending therethrough, the at least one deck board having a top board portion and a bottom board portion, the at least one deck board having at least two dovetail slots in said bottom board portion, the dovetail slots being substantially perpendicular to the longitudinal board axis and being configured to compliment a shape of the dovetail projection; wherein the pallet is assembled by inserting each of the dovetail projections into a corresponding dovetail slot of the at least one deck board.
[0015] And in another form of the invention, there is provided a method for assembling a reusable shipping pallet formed from extruded plastic parts, the pallet comprising: providing a reusable shipping pallet formed from extruded plastic parts, the pallet comprising: at least two I-beam constructs, each of the I-beam constructs having a first beam end, a second beam end and a longitudinal beam axis extending therethrough, each of the I-beam constructs having a top beam portion and a bottom beam portion, and each of the I-beam constructs having a dovetail projection along the top beam portion and extending in a direction parallel to the longitudinal beam axis; and at least one deck board having a first board end, a second board end and a longitudinal board axis extending therethrough, the said at least one deck board having a top board portion and a bottom board portion, the at least one deck board having at least two dovetail slots in the bottom board portion, the dovetail slots being substantially perpendicular to the longitudinal board axis and being configured to compliment a shape of the dovetail projection; and inserting each of the dovetail projections into a corresponding dovetail slot of the at least one deck board.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] These and other objects and features of the present invention will be more fully disclosed or rendered obvious by the following detailed description of the preferred embodiment of the invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts and further wherein:
[0017] FIG. 1 is a schematic top view of a novel pallet formed in accordance with the present invention;
[0018] FIG. 2 is a schematic front view of the novel pallet shown in FIG. 1 ;
[0019] FIG. 3 is a schematic sectional view taken along line 3 - 3 of FIG. 1 ;
[0020] FIG. 4 is a schematic sectional view taken along line 4 - 4 of FIG. 1 ;
[0021] FIG. 5 . is a schematic side sectional view of an I-beam component utilized in the construction of the pallet shown in FIG. 1 ;
[0022] FIG. 6 is a schematic sectional view of a deck board component utilized in the construction of the pallet shown in FIG. 1 ;
[0023] FIG. 7 is a schematic sectional view showing a dovetail slot machined into the bottom of the deck board shown in FIG. 6 ;
[0024] FIG. 8 is a schematic sectional view showing a dovetail insert used to secure the deck board shown in FIG. 6 to the I-beam shown in FIG. 5 ;
[0025] FIG. 9 is a schematic sectional view showing the dovetail insert shown in FIG. 8 installed in the dovetail slot formed in the deck board shown in FIG. 7 ;
[0026] FIG. 10 is a schematic side view showing a stop plate attached to the I-beam;
[0027] FIG. 11 is a schematic top view of another novel pallet formed in accordance with the present invention;
[0028] FIG. 12 is a schematic front view of the novel pallet shown in FIG. 11 ;
[0029] FIG. 13 is a schematic sectional view taken along line 13 - 13 of FIG. 11 ;
[0030] FIG. 14 is a schematic sectional view taken along line 14 - 14 of FIG. 11 ;
[0031] FIG. 15 is a schematic side sectional view of an I-beam component, including an integral dovetail portion, utilized in the construction of the pallet shown in FIG. 11 ;
[0032] FIG. 16 is a schematic sectional view of a deck board component utilized in the construction of the pallet shown in FIG. 11 ;
[0033] FIG. 17 is a schematic sectional view showing a dovetail slot machined into the bottom of the deck board shown in FIG. 16 ;
[0034] FIG. 18 is a schematic sectional view showing the integral dovetail portion of the I-beam component shown in FIG. 15 installed in the dovetail slot formed in the deck board shown in FIG. 17 ; and
[0035] FIG. 19A-19C are schematic side views showing a dovetail slot partially cut into the I-beam.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0036] Looking first at FIGS. 1-4 , there is shown a novel pallet 5 formed in accordance with the present invention. Pallet 5 generally comprises a plurality of I-beams 100 , a plurality of deck boards 200 and a plurality of dovetail inserts 300 ( FIG. 3 ) which are used to connect deck boards 200 to I-beams 100 .
[0037] In general, pallet 5 is intended to be manufactured out of environmentally safe, recyclable polymers and copolymers that are preferably formulated with ultraviolet inhibitors (to resist degradation from the sun) and with modifiers (for strength). Currently, the choice of materials includes acrylics, rubbers, ethylenes, propylenes, urethanes, styrene glasses and structural foams. However, the present invention is not restricted to these particular materials; other appropriate materials may also be used. In this respect it should be appreciated that the particular materials used, and their specific formulations, may be varied according to a variety of factors including strength, durability, cost, etc. Thus, the choice of materials may be influenced by the weight of the load which is to be carried by the pallet. For example, where the pallet is to be used to carry a relatively light load (e.g., cornflakes), a particular blend may be used; correspondingly, where the pallet is to be used to carry a relatively heavy load (e.g., cinderblocks), a different blend may be used. Varying the formulation to suit the load may reduce the cost of the pallet where the pallet is intended to be consistently used with particular types of loads.
[0038] Specific colors can be introduced to the formulation at the customer's request. The use of different colors in the pallets can help with product identification in inventory and warehousing.
[0039] Also, company logos can be permanently embossed into the pallet for recognition, thereby facilitating return of the pallet to the proper owner.
[0040] Looking next at FIGS. 1-5 , a plurality of I-beams 100 generally form the foundation of pallet 5 . I-beams 100 are preferably formed by extrusion (although they may also be formed by another process, e.g., molding) and may have any desired length. In one preferred form of the invention, I-beams 100 have a length of approximately 36.5 inches. I-beams 100 have a cross-sectional configuration which is designed to provide maximum strength with minimum weight. In one preferred form of the invention, the interior of the I-beam is cored out so as to reduce weight while maintaining adequate strength in the vertical and horizontal planes. Each I-beam is preferably four inches high by two inches wide. In this respect it should be appreciated that the four inch height generally facilitates forklift and pallet jack entry into the completed pallet, such that the pallet can be lifted and moved about. Preferably the leading and trailing edges of each I-beam are rounded off, e.g., at 105 ( FIG. 2 ), so as to reduce friction when the pallet is pushed or dragged forward.
[0041] If desired, oval cutouts 110 ( FIG. 2 ) may also be formed in the I-beams after extruding, e.g., by machining. Such cutouts 110 permit forklift entry into the sides of the completed pallet, such that the pallet can be addressed from the sides (i.e., perpendicular to I-beams 100 ) as well as from the ends (i.e., parallel to I-beams 100 ). Preferably the side edges of each I-beam are rounded off, e.g., at 115 ( FIG. 5 ), so as to reduce friction when the pallet is pushed or dragged sideways.
[0042] A pair of coplanar, inwardly-extending grooves 120 ( FIG. 5 ) are formed in the sidewalls of the I-beam near the top and bottom ends of the beam. These grooves 120 receive counterpart tongues 305 ( FIG. 8 ) formed on dovetail inserts 300 , whereby dovetail inserts 300 (and hence deck boards 200 ) may be secured to I-beams 100 , as will hereinafter be described in further detail. In this respect it will be appreciated that by placing grooves 120 near both the bottom and top of the I-beams, deck boards 200 may be secured to both the top and bottom ends of the I-beams. Such bottom deck boards may be necessary or desirable where additional strength is required.
[0043] Preferably, the I-beam is totally symmetrical about the vertical and horizontal axes, such that no specific orientation is required during use.
[0044] Looking next at FIGS. 1-4 , 6 and 7 , a plurality of deck boards 200 form the upper surface of pallet 5 . Deck boards 200 are of two types: inner deck boards 200 ′ ( FIG. 1 ) and outer deck boards 200 ″ ( FIG. 1 ). Inner deck boards 200 ′ and outer deck boards 200 ″ are preferably identical to one another, except as will hereinafter be described.
[0045] Deck boards 200 are generally similar to a slat, except that they preferably have a series of parallel grooves 205 ( FIG. 6 ) on the top surface thereof which serve as gutters for liquid (e.g., rainwater) run-off. This configuration reduces the amount of standing water that will contact the packaged product resting on the pallet and reduces pallet weight without sacrificing pallet strength.
[0046] The bottom surfaces of the deck boards 200 have dovetailed slots 210 ( FIG. 7 ) formed therein. Dovetailed slots 210 extend at a right angle to the longitudinal axis of the deck board, and serve to receive dovetail inserts 300 therein ( FIG. 3 ), whereby deck boards 200 may be secured to I-beams 100 . Deck boards 200 are preferably formed by extrusion (although they may also be formed by another process, e.g., molding), with the bottom dovetailed slots 210 being machined into the bottom of the deck boards.
[0047] Looking next at FIGS. 3, 8 and 9 , dovetail inserts 300 are preferably secured to deck boards 200 by press fitting the dovetail inserts into dovetail slots 210 and then sonically welding the elements together. As a result, dovetail inserts 300 and deck boards 200 together form a subassembly which may then be secured to I-beams 100 . To this end, dovetail inserts 300 have a profile which matches corresponding portions of I-beams 100 , such that the dovetail inserts 300 (and hence their attached deck boards 200 ) can be slidingly attached to I-beams 100 . More particularly, dovetail inserts 300 include a pair of inwardly extending tongues 305 ( FIG. 8 ) which are received in the inwardly extending grooves 120 ( FIG. 5 ) formed in I-beams 100 , in the manner shown in FIG. 3 . In this respect it should be appreciated that the inwardly-extending tongues 305 of dovetail insert 300 are preferably slightly longer than the inwardly-extending grooves 120 of I-beams 100 , so that compression will be established when the dovetail inserts are slid onto the I-beams ( FIG. 3 ). This compression stabilizes the elements relative to one another so as to give the pallet stability. Dovetail inserts 300 are preferably formed by extrusion (although they may also be formed by another process, e.g., molding).
[0048] The inner deck boards 200 ′ can be slid the full length of I-beams 100 .
[0049] The outer deck boards 200 ″ include a stop plate 315 ( FIG. 10 ) that restricts the outer board from being forced too far inward along the I-beams. The stop plates 315 are preferably sonically welded to the faces of the dovetail inserts 300 . The outer deck boards 200 ″ are used on the two opposing ends of the I-beams so as to form the ends of the pallets.
[0050] The pallet is preferably assembled as follows. First, dovetail inserts 300 are secured to deck boards 200 ( FIG. 9 ) and, in the case of the outer deck boards 200 A″, stop plates 315 ( FIG. 10 ) are attached to the dovetail inserts 300 . Then the I-beams 100 are set horizontally on their width by length faces, parallel to one another, and clamped in place. The deck boards 200 ′ are lined up on the I-beams and driven, preferably with a rubber mallet, to their pre-determined locations on the I-beams. Two of the outer deck boards 200 ″ ( FIG. 1 ) are then placed on opposing ends of the I-beams and set in place, thereby completing assembly of the pallet. This assembly operation can generally be accomplished in less than two minutes.
[0051] When desired, the pallet can be disassembled by sliding deck boards 200 off I-beams 100 .
[0052] The novel pallet of the present invention (including, among other things, its extruded I-beams, grooved deck boards and dovetail compression clamps) are unparalleled in the wooden pallet industry. The unlimited availability of a wide variety of material formulations, both current and future, effectively eliminates the aforementioned problems of product contamination, recycling, and landfill rejection, and significantly reduces transportation costs. In addition, the new design increases the product load in airfreight, since the reduced weight of the pallet can be converted into increased working load. The new design also reduces warehousing and storage space, which yields further cost savings.
[0053] Significantly, all of the components of the pallet may (but need not) be extruded, which is highly advantageous with respect to ease and cost of manufacture.
[0054] Furthermore, the novel dovetail connection established between I-beams 100 and deck boards 200 provides an attachment mechanism which is (1) easy and reliable and inexpensive to manufacture; (2) simple and fast to assemble; (3) strong and effective in operation, able to carry large pallet loads without deformation; (4) simple and fast to disassemble; and (5) reusable.
[0055] In addition, due to the modular construction of the pallet, a damaged pallet can be repaired, i.e., any damaged pallet components are removed and replaced by fresh components.
[0056] Looking first at FIGS. 11-14 , there is shown a novel pallet 5 A also formed in accordance with the present invention. Pallet 5 A generally comprises a plurality of I-beams 100 A and a plurality of deck boards 200 A, with I-beams 100 A each comprising a dovetail projection 300 A ( FIG. 13 ) and deck boards 200 A each comprising a dovetailed slot 210 A which are used to connect deck boards 200 A and I-beams 100 A.
[0057] In general, pallet 5 A is intended to be manufactured out of environmentally safe, recyclable polymers and copolymers that are preferably formulated with ultraviolet inhibitors (to resist degradation from the sun) and with modifiers (for strength). Currently, the choice of materials includes acrylics, rubbers, ethylenes, propylenes, urethanes, styrene glasses and structural foams. However, the present invention is not restricted to these particular materials; other appropriate materials may also be used. In this respect it should be appreciated that the particular materials used, and their specific formulations, may be varied according to a variety of factors including strength, durability, cost, etc. Thus, the choice of materials may be influenced by the weight of the load which is to be carried by the pallet. For example, where the pallet is to be used to carry a relatively light load (e.g., cornflakes), a particular blend may be used; correspondingly, where the pallet is to be used to carry a relatively heavy load (e.g., cinderblocks), a different blend may be used. Varying the formulation to suit the load may reduce the cost of the pallet where the pallet is intended to be consistently used with particular types of loads.
[0058] Specific colors can be introduced to the formulation at the customer's request. The use of different colors in the pallets can help with product identification in inventory and warehousing.
[0059] Also, company logos can be permanently embossed into the pallet for recognition, thereby facilitating return of the pallet to the proper owner.
[0060] Looking next at FIGS. 11-15 , a plurality of I-beams 100 A generally form the foundation of pallet 5 A. I-beams 100 A are preferably formed by extrusion (although they may also be formed by another process, e.g., molding) and may have any desired length. In one preferred form of the invention, I-beams 100 A have a length of approximately 36.5 inches. I-beams 100 A have a cross-sectional configuration which is designed to provide maximum strength with minimum weight. In one preferred form of the invention, the interior of the I-beam is cored out so as to reduce weight while maintaining adequate strength in the vertical and horizontal planes. Each I-beam is preferably four inches high by two inches wide. In this respect it should be appreciated that the four inch height generally facilitates forklift and pallet jack entry into the completed pallet, such that the pallet can be lifted and moved about. Preferably the leading and trailing edges of each I-beam are rounded off, e.g., at 105 A ( FIG. 12 ), so as to reduce friction when the pallet is pushed or dragged forward. Alternatively, for rack mounting, the leading and tailing edges may be squared off, or they may be otherwise tailored for a particular application.
[0061] If desired, oval cutouts 110 A ( FIG. 12 ) may also be formed in the I-beams after extruding, e.g., by machining. Such cutouts 110 A permit forklift entry into the sides of the completed pallet, such that the pallet can be addressed from the sides (i.e., perpendicular to I-beams 100 A) as well as from the ends (i.e., parallel to I-beams 10 A). Preferably the side edges of each I-beam are rounded off, e.g., at 115 A ( FIG. 15 ), so as to reduce friction when the pallet is pushed or dragged sideways and to eliminate stress points (in this configuration, pallet 5 A generally comprises a single, i.e., upper, face of deck boards 200 A). It is also preferable to locate oval cutouts 110 A through a lower portion of the sidewalls of the I-beams, so as to provide a continuous crossbar 120 A ( FIGS. 13 and 15 ) above oval cutouts 110 A.
[0062] Dovetail projections 300 A ( FIG. 13 ) are formed in the sidewalls of the I-beam near the top of the beam. These projections 300 A are received by dovetailed slots 210 A formed in deck boards 200 A, whereby deck boards 200 A may be secured to I-beams 100 A, as will hereinafter be described in further detail.
[0063] Looking next at FIGS. 11-14 and 16 - 19 C, a plurality of deck boards 200 A form the upper surface of pallet 5 A. Deck boards 200 A are of two types: inner deck boards 200 A′ ( FIG. 11 ) and outer deck boards 200 A″ ( FIG. 11 ). Inner deck boards 200 A′ and outer deck boards 200 A″ are preferably identical to one another, except as will hereinafter be described.
[0064] Deck boards 200 A are generally similar to a slat, except that they preferably have a series of parallel grooves 205 A ( FIG. 16 ) on the top surface thereof which serve as gutters for liquid (e.g., rainwater) run-off. This configuration reduces the amount of standing water that will contact the packaged product resting on the pallet and reduces pallet weight without sacrificing pallet strength.
[0065] The bottom surfaces of the deck boards 200 A have dovetailed slots 210 A ( FIGS. 17 and 19 A- 19 C) formed therein. Dovetailed slots 210 A extend at a right angle to the longitudinal axis of the deck board, and serve to receive I-beam projections 300 A therein ( FIG. 13 ), whereby deck boards 200 A may be secured to I-beams 10 A. Deck boards 200 A are preferably formed by extrusion (although they may also be formed by another process, e.g., molding), with the bottom dovetailed slots 210 A being machined into the bottom of the deck boards.
[0066] Looking next at FIGS. 13, 18 and 19 A- 19 C, deck boards 200 A are secured to I-beams 100 A by press fitting the dovetail projections 300 A of the I-beams 100 A into dovetail slots 210 A. To this end, dovetailed slots 210 A have a profile which matches corresponding dovetail projections 300 A of I-beams 100 A, such that deck boards 200 A can be slidingly attached to I-beams 10 A.
[0067] The inner deck boards 200 A′ can be slid the full length of I-beams 100 A.
[0068] The outer deck boards 200 A″ include dovetailed slots 210 A″ ( FIGS. 19A-19C ) extending only partially thereacross so as to restrict the outer deck board from being forced too far inward along the I-beams. The outer deck boards 200 A″ are used on the two opposing ends of the I-beams so as to form the ends of the pallets.
[0069] The pallet is preferably assembled as follows. First, dovetail projections 300 A of I-beams 100 A are inserted into dovetailed slots 210 A of inner deck boards 200 ′. Two of the outer deck boards 200 A″ ( FIG. 11 ) are then placed on opposing ends of the I-beams and dovetail projections 300 A of I-beams 100 A are inserted into dovetailed slots 210 A″ of outer deckboards 200 A″, thereby completing assembly of the pallet. This assembly operation can generally be accomplished in less than two minutes.
[0070] When desired, the pallet can be disassembled by sliding deck boards 200 A off I-beams 100 A.
[0071] The novel pallet of the present invention (including, among other things, its extruded I-beams, grooved deck boards and dovetail attachment) are unparalleled in the wooden pallet industry. The unlimited availability of a wide variety of material formulations, both current and future, effectively eliminates the aforementioned problems of product contamination, recycling, and landfill rejection, and significantly reduces transportation costs. In addition, the new design increases the product load in airfreight, since the reduced weight of the pallet can be converted into increased working load. The new design also reduces warehousing and storage space, which yields further cost savings.
[0072] Significantly, all of the components of the pallet may (but need not) be extruded, which is highly advantageous with respect to ease and cost of manufacture.
[0073] Furthermore, the novel dovetail connection established between I-beams 100 and deck boards 200 provides an attachment mechanism which is (1) easy and reliable and inexpensive to manufacture; (2) simple and fast to assemble; (3) strong and effective in operation, able to carry large pallet loads without deformation; (4) simple and fast to disassemble; and (5) reusable.
[0074] In addition, due to the modular construction of the pallet, a damaged pallet can be repaired, i.e., any damaged pallet components are removed and replaced by fresh components.
[0075] A novel reusable shipping pallet, formed from extruded plastic parts which are easily assembled and disassembled, has been disclosed. While various preferred embodiments have been described and illustrated, it will be understood that there is no intent to limit the invention by such disclosure but, rather, it is intended to cover all modifications and alternate constructions falling within the spirit and scope of the invention. | There is disclosed a reusable shipping pallet formed from plastic parts and a method of assembling the same. The pallet comprises at least two I-beam constructs, each of the I-beam constructs having a first beam end, a second beam end and a longitudinal beam axis extending therethrough, each of the I-beam constructs having a top beam portion and a bottom beam portion, and each of the I-beam constructs having a dovetail projection along the top beam portion and extending in a direction parallel to the longitudinal beam axis; and at least one deck board having a first board end, a second board end and a longitudinal board axis extending therethrough, the at least one deck board having a top board portion and a bottom board portion, the at least one deck board having at least two dovetail slots formed in the bottom board portion, the dovetail slots being substantially perpendicular to the longitudinal board axis and being configured to compliment a shape of the dovetail projection; wherein the pallet is assembled by inserting each of the dovetail projections into a corresponding dovetail slot of the at least one deck board. | 8 |
TECHNICAL AREA
The present invention relates to the field of electrical contacts. It relates to a contact element according to the introductory clause to claim 1 .
Such a contact element, in which individual contact webs or contact plates are spring-mounted to a metal sheet band, is manufactured and sold by the applicant under the type designation “MC contact lamella LACu”, or is described in U.S. Pat. No. 4,456,325.
PRIOR ART
Lamellar contact elements or contact lamellae available primarily in two variants have proven themselves in the area of technology relating to electrical contacts for transmission of high currents. In one (single-piece) variant, the entire contact lamella is stamped out of a sheet strip, and molded in such a way as to yield a continuous row of individual contact webs projecting out of the sheet strip plane and sprung by torsion, which are interlinked by continuous lateral webs. If the contact webs are designed symmetrically to the longitudinal axis, the tolerance existing between two contact pieces that can still be bridged by the contact lamella depends on the width of the contact webs. The wider the webs twisted around their longitudinal axis, the higher the tolerance that can be bridged with them. Since the number of webs per length unit of contact lamella, and hence the number of contact points between the contact pieces, diminishes given an increasing width of the contact webs, the level of transmittable currents simultaneously decreases as the size of the bridgeable tolerance rises. To resolve this dilemma, it has already been suggested in the past (e.g., see EP-B1-0 520 950) that the contact webs be designed asymmetrically and interleaved in such a way that the bridgeable tolerance can be increased without having to change the number of webs per unit of length.
In the other variant as known from the production program of the applicant or publication cited at the outset, the functions of spring mounting and contacting are separated. Contact is established via individual, massive and electrically well conducting webs or plates (e.g., Cu or Ag), which are secured to a correspondingly stamped carrier band for purposes of fixation and spring mounting. Even though the functional separation of spring mounting and contacting and associated freedom in material selection in this variant enables an elevated flexibility in layout and simpler optimization of the contacting and resilience properties of the contact lamella, the previously used massive, essentially rectangular contact plates have made it impossible to arrive at higher bridgeable tolerances, and hence to expand the sphere of application of these contact lamellae, at a constant current transfer capacity.
DESCRIPTION OF THE INVENTION
Therefore, the object of the invention is to further develop a contact lamella consisting of a shared carrier band and numerous individual contact elements attached thereto in such a way that it allows a distinctly greater tolerance compensation without diminishing the current transfer capacity.
The object is achieved through, the entirety of features of the invention. The essence of the invention lies in the fact that individual elements are designed as interlaced contact bridges. Interlacing makes it possible to vary the effective width of the individual contact elements, and hence the bridgeable tolerance, within broad limits, without having to alter the periodicity or number per unit of length of the individual elements. Since the individual contact elements or contact bridges can be formed independently from the stamping of the carrier band, optimized geometries for the contact bridges can be realized in a simple manner.
A first preferred embodiment of the invention is characterized by the fact that the contact bridges are essentially V shaped with two free ends and a central bend lying in between, and that the free ends of the contact bridges are secured to the carrier band in such a way that their central bend lies at a predetermined height over the carrier band. In particular, the surface clamped by the V shaped contact bridges is inclined relative to the plane of the carrier band, and the carrier band is designed in such a way that the contact bridges attaché thereto can be resiliently moved toward the carrier band with their central bend. The V shaped bent bridges are easy to manufacture, and their central bend ensures a definite contacting.
The carrier band is preferably divided into individual band sections sequentially arranged in the direction of the longitudinal axis, wherein each band section is allocated a contact bridge, and each band section encompasses two spring-mounted arms that extend from a central web running in the central axis of the carrier band transverse to the longitudinal axis, whose two free ends are secured to the free ends of the accompanying contact bridges. This gives rise to particularly good resilience properties.
A second preferred embodiment of the contact element according to the invention is characterized by the fact that the contact bridges each consist of a wire section, and that, for attaching a contact bridge to the carrier band, the free ends of the contact bridge are routed from one side through recesses in the carrier band and clamped with the carrier band by bending the ends projecting through the recesses to the other side. The advantage to this is that the contact lamella can consist of very simple elements that can be rigidly bonded together without any special additional means.
One alternatively preferred embodiment of the invention is characterized by the fact that the contact bridges are made out of parts stamped out of sheet steel, that, for attaching a contact bridge to the carrier band, the free ends of the contact bridges each have a clamping foot with which it is clamped to the accompanying spring-mounted arm, that the contact bridges are essentially flat stamped parts, that the spring-mounted arms can be turned around their longitudinal axis to incline the contact bridges relative to the plane of the carrier band, and that the contact bridges have an embossed area for purposes of stiffening in the area of the central bend.
It has proven beneficial to arrange the contact bridges in the direction of the longitudinal axis with a contact spacing of several millimeters, preferably 2-8 mm, and to have the deflection of the central bend in the direction of the longitudinal axis relative to the attachment points of the contact bridges to the carrier band with the contact bridges inclined measure several millimeters, preferably about 5-10 mm.
Additional embodiments are described in the subclaims.
BRIEF EXPLANATION OF FIGURES
The invention will be described in greater detail below based on embodiments in conjunction with the drawing. Shown on:
FIG. 1 is a preferred first embodiment of a contact element according to the invention, side view along the longitudinal axis;
FIG. 2 is the contact element from FIG. 1, side view transverse to the longitudinal axis;
FIG. 3 is the contact element from FIG. 1, top views;
FIG. 4 is a perspective view of the contact element from FIG. 1;
FIG. 5 is a perspective view of the contact element according to FIG. 1 inserted into a dovetailed puncture;
FIG. 6 is the incorporation of a (ring-shaped) contact element according to FIG. 1 on a plug;
FIG. 7 is the incorporation of a (ring-shaped) contact element according to FIG. 1 on a socket; and
FIGS. 8-11 is a second preferred embodiment of a contact element according to the invention, depictions comparable to FIGS. 1 - 4 .
WAYS FOR IMPLEMENTING THE INVENTION
FIGS. 1 to 4 show a first preferred embodiment for a contact element (contact lamella) according to the invention in different views (side view, top view, perspective view). The contact element 10 consists of a carrier band 11 made out of stamped sheet steel with good resilience properties and numerous V-shaped, bent contact bridges 12 , which are each bent from a piece of electrically readily conductive, mechanically stable wire comprised of a metal or metal alloy, i.e., a wire section 120 . The carrier band 11 is divided into a central web 110 running in the direction of the longitudinal axis 19 and numerous band sections 111 with parallel spring-mounted arm pairs 112 , 113 , which extend to the outside in the band section 111 to either side of the central web 110 , perpendicular to the latter. Each pair of spring-mounted arms 112 , 113 is allocated to one of the contact bridges 12 .
Each of the V-shaped bent contact bridges 12 has a central bend 121 in the form of a kink. The free ends of the wire section 120 are routed down through the corresponding recesses 116 , 117 in the end areas of the spring-mounted arm pairs 112 , 113 and bent to the inside, so that they run parallel to the carrier band 11 there as clamping feet 122 , 123 . At the same time, the corresponding section of the contact bridge 12 is pressed on the carrier band 11 on the top of the carrier band 11 , so that the contact bridge is reliably and permanently press molded to the carrier band 11 or spring-mounted arms of the respective spring-mounted arm pair 112 , 113 . This simultaneously ensures that the currents to be relayed from the contact element 10 are routed exclusively through the contact bridge 12 , namely from the central bend 121 to the clamping feet 122 , 123 or vice versa. The recesses 116 , 117 can take the form of holes in the spring-mounted arms 112 , 113 . However, it is especially favorable for the automatic production of contact elements 10 if the recesses 116 , 117 , as shown on the figures, are designed as depressions into which the contact bridges 12 can be inserted from the side.
The contact bridges 12 are interlaced on the carrier band 11 , and their free ends are attached to the carrier band 11 in such a way that their central bend 121 lies at a predetermined height over the carrier band 11 . The surface clamped by the V-shaped contact bridges 12 is here oriented at an angle of inclination diagonal to the plane of the carrier band 11 . The height of the central bend 121 over the carrier band 11 as determined by the angle of inclination and length of the wire section 120 is critical for the tolerance between two contact pieces maximally bridgeable by the contact element 10 . The inclined contact bridges 12 attached to the carrier band 11 can be resiliently moved toward the carrier band 11 with their central bend 121 during use primarily because the accompanying spring-mounted arms 112 , 113 turn around their longitudinal axis during such a movement, and act as torsion springs.
To enable the transfer of sufficiently high currents via the contact element 10 in practice, it has proven beneficial to arrange the contact bridges 12 in the direction of the longitudinal axis 19 with a contact spacing a (FIG. 3) of several millimeters, preferably 2-8 mm.
As already mentioned, the length of the contact bridges 12 can be adapted to the requirements at the work location (tolerance to be bridged) within broad limits. However, it has proven beneficial in practice for inclined contact bridges 12 to have the deflection b (FIG. 3) of the central bend 121 in the direction of the longitudinal axis 19 relative to the attachment points of the contact bridges 12 on the carrier 11 measure several millimeters, preferably about 5-10 mm.
The contact elements 10 are preferably incorporated into a (flat) contact piece 13 or a (round) plug 15 or (round) socket 17 in the manner shown on FIGS. 5 to 7 . A puncture 14 with dovetailed cross-sectional profile is provided in the respective contact piece 13 (or 15 , 17 ), into which the contact element 10 is inserted or pushed. To guide the contact element 10 into the puncture 14 , the free ends of the spring-mounted arms 112 , 113 preferably have guide brackets ( 114 , 115 ) bent at a right angle (FIG. 3 ). The floor of the puncture 14 then forms the one contact surface 18 on which the contact bridges 12 rest with their clamping feet 122 , 123 (FIG. 4 ). The opposing (not shown) contact surface is contacted by the central bends 121 . In the case of a round plug 15 (FIG. 6 ), the contact element 10 forms a ring. The same applies to a plug contact made of a plug 16 and socket 17 (FIG. 7 ), in which the contact element 10 is inserted into the socket 17 with the central bends 121 directed inward.
FIGS. 8 to 11 present pictures of a second preferred embodiment for a contact element according to the invention that are comparable to FIGS. 1 to 4 . The contact element 20 again consists of a carrier band 21 made out of stamped sheet steel with good resilience properties and numerous V-shaped, bent contact bridges 22 . The contact bridges 22 are now stamped out of sheet steel consisting of an electrically readily conductive, mechanically stable metal or metal alloy. The carrier band 21 is also divided into a central web 210 running in the direction of the longitudinal axis and numerous band sections 211 with parallel spring-mounted arm pairs 212 , 213 , which extend outwardly to either side of the central web 210 , perpendicularly to the latter. Each pair of spring-mounted arms 212 , 213 is allocated to one of the contact bridges 22 . Guide brackets 214 , 215 are located adjacent the spring-mounted arms 212 , 213 .
Each of the V-shaped stamped contact bridges 22 has a central bend 221 . The free ends of the contact bridge 22 has clamping feet 222 , 223 , with which the contact bridge 22 is reliably and permanently clamped to the spring-mounted arms 212 , 213 of the accompanying band section 211 .
In this embodiment as well, the contact bridges 22 are interlaced according to the invention on the carrier band 21 , wherein their central bend 221 is located at a predetermined height over the carrier band 21 . The surface clamped by the V-shaped contact bridges 22 is here oriented at an angle of inclination diagonal to the plane of the carrier band 21 . Since the contact bridges 22 are essentially flat stamped parts, the spring-mounted arms 212 , 213 are turned around their longitudinal axis (twisted) to incline the contact bridge 22 relative to the plane of the carrier band 21 . For stiffening purposes, the contact bridges 22 each have an embossed area 224 near the central bend 221 , which results in the area being slightly bent toward the top, as readily visible on FIG. 9 . At the same time, this ensures that the electrical contact in the area of the central bend 221 remains defined and largely punctiform, even if the contact bridges 22 are spring-mounted more tightly.
In sum, the new contact element is characterized by the following characteristics and advantages:
It yields a larger working area for bridging large tolerances and angular deviations;
The working area can be enlarged even further by lengthening the lever arm on the contact bridge;
The interlaced arrangement of the contact bridges makes it possible to achieve a low contact spacing, and hence a high current load capacity;
The incorporation width is low, because the hinges of the torsion-stressed spring-mounted arms lie in the middle of the contact element;
A minimal incorporation space (puncture depth) is required;
The separation of spring and contact function yields good resilience properties;
The sliding properties are uniformly low;
Good contacting is achieved via the contact bridges despite a relatively long current path;
A defined 3 point contacting comes about (2 contact points below, 1 contact point above);
The contact element can be used both as a plug or socket lamella (in various diameters) and for flat installation.
REFERENCE NUMBER LIST
10, 20
Contact element
11, 21
Carrier band
12, 22
Contact bridge
13
Contact piece
14
Puncture
15, 16
Plug
17
Socket
18
Contact surface
19
Longitudinal axis
110, 210
Central web
111, 211
Band section
112, 113
Spring-mounted arm
114, 115
Guide bracket
116, 117
Recess
120
Wire section
121, 221
Central bend (kink)
122, 123
Clamping foot
212, 213
Spring-mounted arm
214, 215
Guide bracket
222, 223
Clamping foot
224
Embossed area
a
Contact spacing
b
Deflection | In a contact element ( 10 ) for electrically connecting two contact pieces ( 13, 15, 16, 17 ) opposing each other with contact surfaces ( 18 ), wherein the contact element ( 10 ) extends along a longitudinal axis ( 19 ) and encompasses numerous separate, identical spring-mounted individual elements ( 12 ) that are arranged essentially parallel to each other and transverse to the longitudinal axis ( 19 ), which are secured to a continuous carrier band ( 11 ) extending in the direction of the longitudinal axis ( 19 ), and establish the electrical contact between the contact surfaces, a large working area is achieved while keeping current load capacity high by designing the individual elements as interlaced contact bridges ( 12 ). | 7 |
RELATED APPLICATIONS
This is a continuation of application Ser. No. 08/892,286, filed Jul. 14, 1997 now U.S. Pat. No. 5,879,354, which was a divisional of U.S. patent application Ser. No. 08/649,465, filed May 17, 1996, now U.S. Pat. No. 5,755,803, which was a continuation-in-part application of U.S. patent application Ser. No. 08/603,582, filed Feb. 20, 1996, now U.S. Pat. No. 5,810,827 which was a continuation-in-part application of U.S. patent application Ser. No. 08/300,379, filed Sep. 2, 1994 by Goldstein et al., now U.S. Pat. No. 5,514,139, dated May 7, 1996.
U.S. patent application Ser. No. 08/603,582, filed Feb. 20, 1996, now U.S. Pat. No. 5,810,827, is also a continuation-in-part application of U.S. Ser. No. 08/479,363, filed Jun. 7, 1995, now U.S. Pat. No. 5,643,272 which is a continuation-in-part of U.S. patent application Ser. No. 08/342,143, filed Nov. 18, 1994 by Haines et al., now U.S. Pat. No. 5,597,379, which is a continuation-in-part application of U.S. patent application Ser. No. 08/300,379, filed Sep. 2, 1994, by Goldstein, et al., now U.S. Pat. No. 5,514,139, dated May 7, 1996. U.S. Ser. No. 08/479,363, now U.S. Pat. No. 5,643,272 is also a continuation-in-part of U.S. Ser. No. 08/300,379, Sep. 2, 1994, now U.S. Pat. No. 5,514,139. U.S. Ser. No. 08/603,582, now U.S. Pat. No. 5,810,872 is also a continuation-in-part application of U.S. Ser. No. 08/342,143 now U.S. Pat. No. 5,597,379 which is a continuation-in-part application of U.S. Ser. No. 08/300,379 now U.S. Pat. No. 5,514,139.
The entire disclosures of these related applications are expressly incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention generally relates to a prosthetic apparatus for augmenting a musculoskeletal structure for maintaining or improving said structure, and more particularly to a prosthetic implant for use in reconstructed or replacement knees or other joints.
2. Related Art
Different apparatus have been developed to enable a surgeon to replace damaged osseous and/or articular material of the muscoskeletal structure with prosthetic devices or structures in order to preserve or restore the structural or kinematic function of the body. Keeping in mind that the ultimate goal of any surgical procedure is to restore the body to normal function, it is critical that the quality and orientation of any bone cuts, as well as the quality of fixation, and the location and orientation of objects or devices attached to the bone, is sufficient to ensure proper healing of the body, as well as appropriate mechanical function of the musculoskeletal structure.
While the implant of the present invention has applications throughout the human body, the applications and embodiments shown and described herein are specifically configured for total knee replacement, a surgical procedure where planar or curvilinear surfaces are created in or on bone to allow for the proper attachment or implantation of prosthetic devices. It should be noted that the apparatus and methods set forth herein can modified and applied to any form of joint replacement wherein the function to be restored is dictated by both static and dynamic principles, as well as forms of muscoskeletal reconstruction which are dictated primarily by static principles of operation.
Currently, bony surfaces to be resected or cut are done so in a series of planar surfaces. In total knee replacement, a series of curvilinear surfaces or resections are created in the bone to allow the attachment of a number of prosthetic devices to the femur, tibia, and patella. In the case of the femur, the posterior and distal femoral condyles, the anterior femoral cortex, and other anatomic features are referenced to determine the location and orientation of the resections. The location and orientation of these resections are critical in that they dictate the quality of fixation of the prosthesis to the bone, as well as the final location and orientation of the prosthesis.
There are several major problems inherent in current implant designs caused directly by the need for interior and predominantly planar fixation surfaces (these surfaces are interior surfaces of the implant which mate with the resected bone) embodied in implant designs whose external geometry is predominantly curvilinear. These problems include:
a. the removal of excessive amounts of viable osseous tissues;
b. non-optimal or “unnatural” patellofemoral kinematics;
c. excessive implant rigidity resulting in stress shielding of living bone;
d. stress risers at the vertices of the planar fixation surfaces of the implant leading to potential failure sites under fatigue loading, and
e. excessively massive implants resulting in additional material costs.
Past efforts have not been successful in properly addressing these concerns. Such previous efforts at implants are set forth in the following patents, none of which teach or suggest all of the benefits and advantages of the present invention. These previous patents include:
Goodfellow, et al., U.S. Pat. No. 5,314,482, discloses a femoral implant having a convexly shaped spherical articulation surface and a securement surface having major and minor areas at opposite end portions. The major area is essentially concavely spherically concentric with the articular surface to form a shell body part. The minor area is essentially planar and extends chordally of the articulation surface. The implant further includes a bone-penetrating pin extending radially from the major area in a direction parallel to the longitudinal direction of the minor area.
Walker, et al., U.S. Pat. No. 4,822,365, discloses a method of designing a prosthesis having convex male and concave female portions. The surface of the condylar male portion of the prosthesis is generated by analysis of either an average or specific condyle, or a distortion thereof to fit observed general dimensions of a specific patient. The female surface includes flexion and laxity surfaces. The flexion surfaces are generated by plotting the path of articulation of substantial points of contact between the male portion and a corresponding female portion. The laxity surfaces comprise raised guide-bearing surfaces for resisting dislocation of the condylar portion.
Hanslik, et al., U.S. Pat. No. 4,770,663, discloses a knee joint endoprosthesis comprising a femur with two skid surfaces and a space therebetween. The skid surfaces are interconnected at a front end. The skids having a curvature increasing from the front end to a rear end. The skids are also curved on planes perpendicular to the curvature. The joint endoprosthesis further comprises a tibia component having two surfaces on which the skids ride.
Zichner, et al., U.S. Pat. No. 4,662,889, discloses a knee joint prosthesis having a C-shaped a femur cap for attachment to a resected femur condyle. The cap includes an aperture therethrough for receiving a shaft. A cap is also placed over the tibia. A connecting member is implanted into the tibia and interconnected with the femur by the shaft.
Shoji, et al., U.S. Pat. No. 4,586,933, discloses a knee implant having a femoral component with a curved articulating surface, movable inserts positioned between the femoral component and a tibial tray, the inserts having concave articulating surfaces at the top and bottom thereof, and a tibial tray with convex tracks and posterior stops.
Johnson, et al., U.S. Pat. No. 4,568,348, discloses a knee prosthesis having a femoral component for attachment to the femur, a tibial component for attachment to the tibia and a meniscal component positioned therebetween. The tibial component has a concave bearing surface. The meniscal component has bearing surfaces complimentary to the tibial component and the femoral component. The femoral component has a two-part curved bearing surface including a first curved portion and a second curved posterior portion contiguous with and of relatively lesser curvature than the first curved portion.
Schurman, et al., U.S. Pat. No. 4,358,859, discloses a knee prosthesis comprising a femoral implant having a condyle section and a stem, and a tibial implant having a tibial plateau and a stop plate and a stem.
Forte, et al., U.S. Pat. No. 4,353,135, discloses a knee implant having a patellar flange comprising a curved base and a pair of condylar runners.
Russell, et al., U.S. Pat. No. 4,722,330, discloses a distal femoral surface guide for mounting on an intramedullary alignment guide for use in shaping the distal femoral surface. A conventional shaping means such as an oscillating saw or hand saw is introduced into slots in the surface guide to resect the femur. The device also includes stabilizing members that extend along the sides of the femur to stabilize the device. The attachment surface of the implant comprises a series of planar surfaces.
Lackey, U.S. Pat. No. 5,053,037, discloses a femoral drill guide with interchangeable femoral collets, a femoral reamer and a femoral anterior/posterior cutting block with an adoptable anterior femoral ledge. A plurality of diagonal slots are provided for making diagonal cuts in the distal end of the femur. The attachment surface of the implant comprises a series of planar surfaces.
Ferrante et al. U.S. Pat. No. 5,098,436, discloses a modular guide for shaping a femur comprising a first bracket defining a generally U-shaped structure having an internal surface adapted to be seated on the distal aspect of a resected femur bone and an elongated central opening appointed to expose a selected area of the resected femur, including a curved track for guiding a first shaping tool along a predetermined path for controlled shaping of a curved patellar groove and a portion of the selected area exposed through the opening. A second bracket defines a linear slotted bore extending generally parallel to the long axis of the femur for guiding a second shaping tool to form a relatively deep recess accommodating an intercondylar-stabilizing housing of a knee implant.
Poggie, et al., U.S. Pat. No. 5,250,050 discloses an apparatus for use in preparing the bone surfaces for a total knee prothesis, comprising cutting guides, templates, alignment guides, a distractor and clamping instruments. The instrument for alignment of the cutting surface for resecting the tibia includes an ankle clamp, an adjustable alignment rod, and a cutting platform. After the cutting platform is properly aligned on the tibia, it is pinned thereto and the tibia may be resected using an oscillating saw. Also disclosed is a patella resection guide comprising a scissor-type clamp having distal gripping arms, each of which define a cutting surface, and gripping teeth. The attachment surface of the implant comprises a series of planar surfaces.
Caspari, et al., U.S. Pat. Nos. 5,263,498, 5,228,459, and 5,304,181 disclose a method and apparatus for orthoscopically preparing bone surfaces for a knee replacement. A tibial jig is attached to the tibia at just above the ankle at a lower end and to just below the tibial tubercle at an upper end. One portal is formed in the knee for insertion of an orthoscope for viewing the knee, and another portal is formed for introducing resecting instruments. A cutting platform is aligned and secured in position and a cutting module is attached. Initially, a plunge cut across the tibial eminence is produced. This procedure is repeated until the surface of the tibial plateau is covered with trails having ridges therebetween. Thereafter, the device is passed back and forth over the tibial plateau to remove the ridges. The attachment surface of the implant comprises a series of planar surfaces.
Whiteside, U.S. Pat. No. 4,474,177 describes instruments for creating the distal femoral surfaces where a guide is used to index a flat surface used to guide the distal femoral resection. The attachment surface of the implant comprises a series of planar surfaces.
Kaufman, et al. U.S. Pat. No. 4,721,104 describes a method of preparing the intracondylar area of the distal femur. The attachment surface of the implant comprises a series of planar surfaces.
Collomb, European Application No. 538153-A1, discloses a modular device for positioning a knee prosthesis on a bone. The attachment surface of the implant comprises a series of planar surfaces.
Bert, et al., U.S. Pat. No. 5,234,433, discloses a method and apparatus for unicompartmental total knee arthroplasty. The attachment surface of the implant comprises a series of planar surfaces.
Pynaov, Russian Application No. 577,020, discloses an instrument for shaping the end joint of a bone to prevent arthrosis and ankylosis. The instrument is used to remove a central portion of the joint so that the joint ends are contacted in one plane without causing irritation in the para-articular tissues. No implant structure is disclosed.
None of these previous efforts, however, disclose all of the benefits and advantages of the present invention, nor do these previous patents teach or suggest all the elements of the present invention.
OBJECTS AND SUMMARY OF THE INVENTION
It is a primary object of the present invention to provide an apparatus to properly replace damaged bony tissues.
It is also an object of this invention to provide an apparatus to properly replace damaged bony tissues in joint replacement surgery.
It is also an object of the present invention to provide an implant for the attachment to a distal femur in the context of knee replacement surgery.
It is an additional object of the present invention to provide a method and apparatus for making a curvilinear implant.
It is another abject of the present invention to provide an implant having a reduced thickness to reduce the amount of material required to make the implant.
It is even another object of the present invention to provide an implant having curvilinear fixation surfaces for increasing the strength of the implant.
It is another object of the present invention to provide an implant having a fixation surface that is anterior-posterior curvilinear and medio-lateral curvilinear.
It is another object of the present invention to provide an implant that has a fixation surface that is shaped to resemble a natural distal femur.
It is also an object of the present invention to provide an implant apparatus for allowing proper patellofemoral articulation.
It is a further object of the present invention to provide for minimal stress shielding of living bone through reduction of flexural rigidity.
It is an additional object of the present invention to provide an implant apparatus having internal fixation surfaces which allow for minimal bony material removal.
It is another object of the present invention to provide an implant apparatus with internal fixation surfaces that minimize stress risers.
It is another object of the present invention to provide an implant apparatus having internal fixation surfaces for precise fixation to curvilinear body resections.
It is another object of the present invention to provide an implant apparatus having internal fixation surfaces for precise apposition to curvilinear body resections.
It is another object of the present invention to provide an implant apparatus having internal fixation surfaces for curvilinear interior fixation geometries closely resembling the geometry of the external or articular geometry of the implant apparatus.
It is also an object of this invention to provide a method and apparatus for properly locating and orienting a prosthetic implant with respect to a bone.
It is another object of the present invention to provide an implant which is simple in design and precise and accurate in operation.
It is also an object of the present invention to provide an implant which minimizes the manual skill necessary to complete the procedure.
It is still yet another object of the present invention to provide an implant which minimizes the amount of bone removed.
It is even another object of the present invention to provide a method and apparatus for removing material from a bone such that both the cutting path and cutting profile are predominantly curvilinear.
These objects and others are met by the implant of the present invention which has an outer bearing surface and an inner attachment surface. The outer bearing surface functions as a joint contact surface for the reconstructed bone. The inner attachment surface contacts a bone and is attached thereto. The inner attachment surface of the implant is curvilinear from an anterior to a posterior area of the femur, as is conventionally known, and is also curvilinear from a medial to a lateral area of the femur to approximate the shape of natural femur. The resection of the femur for accommodating the implant can be properly performed by a milling device employing one or more curvilinear milling bits.
There are numerous advantages associated with the curvilinear implant of the present invention. First, it will allow for a very thin implant cross-section and therefore necessitate the removal of the least amount of viable osseous tissue. Accordingly, the kinematics of the artificial joint could be made to be as close as possible to that of a healthy, natural knee joint. In addition, the curvilinear geometry of the implant dramatically decreases the stress risers inherent in conventional rectilinear femoral implants and allows for a thinner cross-sectional geometry while potentially increasing the resistance of the implant to mechanical failure under fatigue or impact loading. Conversely, the curvilinear geometry of the implant may also allow for an advantageous reduction in the flexural rigidity of the implant which may result in avoidance of the “stress-shielding” inherent in rigid implant designs.
This curvilinear implant of the present invention could also result in a less expensive femoral implant because of the reduced amount of material needed for the implant, as well as an improved, more natural, and even stronger knee replacement. The cross-section of the implant could be varied to assist in seating the implant and to increase the strength and fit of the implant. The implants of the present invention having curvilinear implant surfaces could be fabricated of metal, plastic, or ceramic or any other material. Further, the thickness of the implants and the material required to fabricate the implant could be reduced as the implants are adapted to increasingly curvilinear surfaces.
The resected surfaces of a femur or other bone to accept the implant of the present invention could be prepared by the apparatus and method for resection shown and described in the prior related applications set forth herein, the entire disclosures of which are expressly incorporated herein by reference.
BRIEF DESCRIPTION OF THE DRAWINGS
Other important objects and features of the invention will be apparent from the following Detailed Description ofthe Invention taken in connection with the accompanying drawings in which:
FIG. 1 is a perspective view of a femoral implant of the present invention having a curvilinear implant fixation surface.
FIG. 2 is a side plan view of the femoral implant shown in FIG. 1, FIGS. 2A, 2 B, 2 C and 2 D being sectional views taken along lines A—A, B—B, C—C and D—D of FIG. 2, respectively.
FIG. 3 is a perspective view of a curvilinear milling bit and resection guide for creating a curvilinear resection in a bone for accepting the curvilinear implant shown in FIG. 1 .
FIG. 4 is a side plan view of the curvilinear milling bit and resection guide shown in FIG. 3 .
FIG. 5 is a perspective view of another embodiment of a milling bit for creating a resection in a bone for accepting the curvilinear implant of the present invention.
FIG. 6 is a side plan view of another embodiment of the femoral implant shown in FIG. 1 .
FIG. 7 is a front plan view of another curvilinear milling bit for creating a curvilinear resection in a bone for accepting the curvilinear implant shown in FIG. 1 .
DETAILED DESCRIPTION OF THE INVENTION
The particular example of the present invention discussed herein relate to a prosthetic implant for attachment to a femur in the context of total knee arthroplasty, i.e. a femoral implant. However, it should be pointed out that the principles described herein may be applied to any other applications where foreign or indigenous material is affixed to any other anatomic feature.
As shown generally in FIGS. 1 and 2, the implant apparatus of the present invention, generally indicated at 10 , comprises curvilinear interior fixation surface 20 as well as curvilinear exterior bearing surface 40 . Importantly, the implant of the present invention includes curvilinear surfaces extending from an anterior to a posterior area of the femur and/or implant, as is conventionally known, as well as curvilinear surfaces extending from a medial to a lateral area of the femur and/or implant to approximate the shape of natural femur. In other words, the fixation path (i.e. corresponding to the cutting path along which the milling bit rides to resect the femur; indicated by arrow A in FIG. 1) as well as the fixation profile (as one proceeds along the cutting profile orthogonally to the cutting path; indicated by arrow B in FIG. 1) are both predominantly curvilinear. As such, the cutting profile (arrow B) of the interior fixation surface 20 could include a curved or flat 22 and another curved or flat area 24 therebetween. Preferably, the outer areas 22 are flat or relatively flat and the inner area 24 is curved to approximate the shape of a natural distal femur 12 . It should be pointed out the outer areas 22 could be curved, and the inner area 24 could also be curved, but embodying differing radii of curvature. Additionally, it should be pointed out the geometry of the internal fixation surface 20 of the implant 10 could be varied as desired. As such, any combination of flat surfaces and curvilinear surfaces could be used. As shown in FIG. 2, and in more detail in FIGS. 2A, 2 B, 2 C and 2 D, the cross-sectional thickness and medio-lateral width of the implant of the present invention could vary along the implant 10 . This variance results from merging a cutting tool to cut a bone, i.e., the implant 10 closely resembles in size and shape the material removed from the bone. Accordingly, the cut starts as a point 25 and grows in depth and width.
The curvilinear bone surfaces necessary for proper fixation of such an implant 10 may be generated through the use of the curvilinear milling bit or form cutter and the curvilinear cutting path means discussed in the previous related applications set forth herein, the entire disclosures of which are expressly incorporated herein by reference. Basically, the milling bit has a profile resulting in form cutter configuration which is concentric about its longitudinal axis to effect a curvilinear cutting profile for receiving the implant of the present invention. One embodiment of such a form cutter is shown in FIGS. 3 and 4. While it is possible to use multiple form cutters with differing geometries and therefore an implant 10 with an internal geometry that varies along the cutting path from the anterior to the posterior of a femur, for the sake of intraoperative time savings, a single anatomically optimal form cutter is preferable.
The form cutter shown in FIGS. 3 and 4 comprises a cutting guide 80 having a cutting paths 82 interconnected by member 81 . A milling bit 90 having cylindrical milling areas 92 at the ends, and a curved milling area 94 at the center could be used. Of course, the milling areas carry cutting teeth. Spindles 91 interconnected at each end of the milling bit 90 could engage and ride the cutting path 82 of the cutting guide 80 . The milling bit 90 is then guided along the cutting path 82 by means of a handle. Importantly, the shape of the milling bit 90 could be varied as desired to create a resection having a desired cutting path as well as a desired cutting profile.
The medio-lateral cross-sectional internal geometry of such an implant 10 , and therefore the necessary resected bony surfaces of the femur, are consistent about the cutting path in a single form cutter system. It should be noted that the implant 10 may possess a notch 60 between members 62 (posterior femoral implant condyles) in the areas approximately between the distal and posterior femoral condylar areas to accommodate the posterior cruciate ligament, as well as for other reasons. Because of the notch 60 between the posterior femoral condyles, the form cutter may not cut any material in the notch 60 .
Additionally, it may be advantageous to utilize a secondary form cutter as shown in FIG. 5 for use in creating a slot or slots in or near the distal area of the femur before or after it has been resected. Such a secondary cutter 70 would include engagement means 72 for engagement with driving means, and a shaft 74 carrying one or more cutters 76 for cutting slots into the femur through one or more of the resected surfaces thereof.
Through the inclusion of an additional or adjunct cutting path in the pattern means, it would be advantageous to utilize the form cutter to create the aforementioned slots in the distal femur to accommodate the fixation fins which may be molded as an integral part of the interior surface of the implant 10 . An implant with fixation fins is shown in FIG. 6 . The fins 28 would provide medio-lateral fixation stability in addition to that provided by the trochlear groove geometry of the implant 10 . Further, the fins also provide for additional surface area for bony contact and ingrowth to increase implant fixation both in cemented and cementless total knee arthroplasty.
FIGS. 7 shows another embodiment of a milling bit, generally indicated at 190 for creating a curvilinear cutting path and curvilinear cutting profile in femur 12 . In this embodiment, the transition from a first cutting area 192 to a second cutting area 194 is continuous and smooth. This milling bit 190 also includes spindles 191 at the ends thereof for engagement with pattern means to guide the milling bit along a cutting path.
There are numerous advantages to the femoral component herein described. Foremost, it will allow for the thinnest implant cross-section possible (perhaps 3 mm to 6 mm in nominal thickness) and therefore necessitate the removal of the least amount of viable osseous tissue. This is especially critical in situations where the probability of revision surgery is high and the amount of viable bone available for revision implant fixation and apposition is a significant factor in the viability of the revision procedure. Since the form cutter configuration allows for similar amounts of tissue to be removed from the trochlear groove, the bony prominences surrounding the trochlear groove, the femoral condyles, and the other articular surfaces of the femur, the external geometry of the femoral implant can be optimized for patellofemoral articulation as well as tibiofemoral articulation. In essence, the kinematics of the artificial joint could be made to be as close as possible to that of a healthy, natural knee joint.
In addition, the curvilinear geometry of the implant dramatically decreases the stress risers inherent in conventional rectilinear femoral implants and allows for a thinner cross-sectional geometry while potentially increasing the resistance of the implant to mechanical failure under fatigue or impact loading. The implant could have a relatively consistent cross-sectional thickness throughout the implant, or it could be varied as desired.
The curvilinear geometry of the implant may also allow for an advantageous reduction in the flexural rigidity of the implant which may result in avoidance of the “stress-shielding” inherent in rigid implant designs. Stress shielding being a phenomenon that may occur when living bony tissue is prevented from experiencing the stresses necessary to stimulate its growth by the presence of a stiff implant. This phenomenon is analogous to the atrophy of muscle tissue when the muscle is not used, i.e. when a cast is placed on a person's arm the muscles in that arm gradually weaken for lack of use.
Further, the curvilinear implant of the present invention could allow for the use of a ceramic material in its construction. Since ceramics are generally relatively weak in tension, existing ceramic implant designs contain very thick cross-sections which require a great deal of bony material removal to allow for proper implantation. Utilization of ceramics in the curvilinear implant would not only allow for the superior surface properties of ceramic, but also avoid the excessively thick cross-sections currently required for the use of the material.
The curvilinear implant of the present invention could result in a less expensive femoral implant because of the reduced amount of material needed for the implant, as well as an improved, more natural, and even stronger knee replacement. It may desirable to vary the cross-section of the implant to assist in seating the implant, to increase the joint kinematics and to increase the strength and fit of the implant. The implant of the present invention could be fabricated of metal, plastic, or ceramic or any other material or combination thereof. Further, the thickness of the implants and the material required to fabricate the implant could be reduced as the implants are adapted to increasingly curvilinear surfaces. Also, it should be pointed out that such implants with curvilinear implant surfaces require less bone to be removed to obtain a fit between the implant and the bone. Finally, it should be noted that curvilinear milling bits hereinbefore described would work well for preparing a bone to receive an implant with curvilinear interior implant surface.
Importantly, by using a milling bit having a curved profile, one can cut a femur to resemble the natural shape of the femur, i.e. the resected femur would include condylar bulges and a central notch. This would reduce the amount of bony material that must be removed from the femur while maintaining the structural integrity of the femur. Of course, any prosthetic implant used for attachment to a femur resected by the curved profile milling bit would necessarily have an appropriately contoured inner fixation surface for mating with contoured surface of the femur. Additionally, it should be noted that the curved profile milling bit could have one or more curvilinear bulges along the length thereof as shown in FIGS. 3 and 4, or alternatively, could have one or more bulges discretely formed along the length thereof
Modifications of the foregoing may be made without departing from the spirit and scope of the invention. What is desired to be protected by Letters Patents is set forth in the appended claims. | An implant is provided for which has an outer bearing surface and an inner attachment surface. The outer bearing surface functions as ajoint contact surface for a reconstructed bone joint. The inner attachment surface contacts a bone and is attached thereto. The inner attachment surface of the implant is curvilinear from the anterior to the posterior area of the femur, and is also curvilinear from the medial to the lateral areas of the femur to approximates the shape of natural femur. The resection of the femur for accommodating the implant can be properly performed by a milling device employing one or more curvilinear milling bits. | 0 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device for analyzing the function of a heart, having a measurement unit for generating a measurement signal related to an electrical or mechanical heart variable, and an evaluation unit for evaluating the measurement signal.
2. Description Of the Prior Art
In the monitoring, diagnosis and treatment of a heart's function, accurate determination of the heart's current condition, with minimal risk of erroneous interpretations, is important. Automatic monitoring of the heart is a valuable asset in the treatment of heart disease so that a therapeutic measure can be instituted without delay when necessary.
The electrocardiogram (ECG) is one heart variable which is an indicator of a heart's function. Sensing the ECG in order to obtain a measurement signal which can be evaluated in establishing the condition of the heart is known in the art.
One way to graphically elucidate the electrocardiogram by plotting the voltage in a recorded electrocardiogram against the time derivative of the voltage is described in an article entitled "Phase Plane Plot of Electrograms as a Marker of Ventricular Electrical Instability During Acute Ischemia: Initial Experimental Results and Potential Clinical Applications", published in the journal PACE, Vol. 15, part II, November 1992, pp. 2188-2193. This procedure produces a curve corresponding to the ECG signal. The article shows that there is a relationship between changes in parts of the curve during acute ischemia and the development of ventricular fibrillation. The authors of the article state that a presentation of an electrocardiogram in graphical form can be an excellent complement to traditional, real-time presentation.
U.S. Pat. No. 4,417,306 describes an apparatus which monitors and stores heart signals. The apparatus senses the ECG, and the ECG signal must have a predesignated slope, amplitude, duration and course to be accepted as a heart beat. The QRS complex is the main segment sensed, i.e., the electrical signals which occur in the heart when there is a ventricular beat (ventricular systole).
U.S. Pat. No. 4,453,551 describes an apparatus designed to detect ventricular fibrillation (VF). The apparatus senses the ECG signal from the heart, digitizes it and amplifies it to a predetermined amplitude. The amplified signal can then be analyzed in different ways to ascertain whether or not VF is present. For example, the statistical distribution of gradients or the frequency of the maximum negative gradient can be analyzed.
European Application 0 220 916 describes an apparatus designed to detect the presence of ventricular tachycardia (VT) and VF and to supply treatment to terminate these conditions. The apparatus senses the heart's ECG at a plurality of points on the heart and determines the sequence in which the signals are detected at the different measurement points. In VT and VF, the sequence deviates from the normal pattern in different ways.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a device which analyzes the function of the heart in a reliable, efficient but still simple manner.
Another object is to provide a device which can be used for diagnosing heart defects, monitoring heart functions and adapting therapy to make treatment as safe and effective as possible.
The above objects are achieved in accordance with the principles of the present invention a device having a measurement and evaluation unit wherein the evaluation unit includes means for generating at least one parameter signal on the basis of the measurement signal, and the evaluation unit analyzes related values for the measurement signal and the parameter signal by determining whether they satisfy a predesignated number of conditions.
Instead of analyzing only one measurement signal, the device first generates a parameter signal from the measurement signal, and related signal values of the measurement signal and parameter signal are analyzed. A normally working heart (as in a healthy heart) is hemodynamically stable, and a virtually identical sequence of related values is generated from one heart cycle to another, so different conditions are satisfied in the same sequence cycle after cycle. Pathological changes and other abnormal conditions in a heart affect the satisfying of different conditions in a distinct way and can therefore be easily identified. The conditions can consist of any kind of mathematical relationship. Certain relationships for different, known changes in a specific individual can also be used.
Preferably, the related variables correspond to coordinates forming a curve in a coordinate system, with the measurement signal and parameter signal as coordinate axes, and preferably the predetermined number of conditions corresponds to a predetermined number of areas in the coordinate system, whereby the evaluation unit determines the sequence in which the curve traverses the predetermined number of areas.
Having the related values correspond to coordinates in a coordinate system results in a clarified analysis. The generated curve becomes virtually identical, from one heart cycle to another, as long as the heart functions in a constant manner.
An application filed simultaneously herewith having U.S. Ser. No. 08/051,250 entitled "Device for Analyzing the Functioning of a Heart" (Noren et al.,), filed Apr. 23, 1993 describes a device which analyzes heart-related signals by utilizing a two- or multidimensional representation of the signals.
In another embodiment of the device in accordance with the invention the means for generating at least one parameter signal from the measurement signal is a differentiator which obtains the first derivative of the measurement signal.
With the derivative of the measurement signal as a parameter, related values are obtained which, for a normal heart, form a substantially closed curve with a small loop inside a larger loop in the coordinate system. This curve changes when e.g. a VT or a VF is present. Definition of different areas the curve can pass in various heart conditions and the determining of the areas the curve passes and in which sequence the areas are passed make it possible to identify different arrhythmias and anomalies. The curve changes even when certain other specific cardiac events occur, such as retrograde conduction and extrasystoles. Spontaneous and stimulated heart beats give rise to different curves, and the device can be used for detecting both spontaneous heart beats and stimulated heart beats.
As an alternative or a complement to differentiation, the means for generating a parameter signal from the measurement signal may be or include an integrator which integrates the measurement signal.
By the use of an integrated signal, with integration occurring over a plurality of heart cycles, the system is more stable, and the curve does not wander outside the predetermined decision areas. If the integration interval is shorter than a heart cycle, a parameter signal is produced which with the measurement signal, forms a curve in the same way as the measurement signal and the measurement signal's derivative. Integration produces simultaneous filtration of noise.
An enhancement of the device is achieved in an embodiment of the invention wherein the evaluation unit has a plurality of comparators, each of which is supplied with at least one of the measurement signal or the parameter signal and an input signal. Each comparator represents a line in the coordinate system, which lines delineate the predetermined number of areas. Each corresponding comparator generates an output signal when the curve being analyzed is on one side of a specific line, associated with that comparator. The evaluation unit in this embodiment also includes a sequence analyzer for determining the sequence in which the comparators generate output signals.
Each comparator thus represents a line in the coordinate system, and the comparator's output signal is zero or one ("low" or "high"), depending on which side of the line the curve is located. With a plurality of lines, the coordinate system is subdivided into a plurality of areas which can be made larger or smaller. On the basis of the comparators' output signals, the course of the curve can be followed throughout each heart cycle and compared with various predetermined courses in order to determine the condition of the heart. The lines can be parallel to one another, perpendicular to one another, arise from a common point, arise from a plurality of points, etc.
In order to be able to shift the curve in relation to the coordinate system and additionally to form a plurality of different lines, preferably the evaluation unit further includes a reference signal generator which generates a reference signal serving as the input signal for at least one comparator.
An additional enhancement is obtained in a further embodiment of the invention including a first timer for measuring the time in which the related values satisfy at least one specific condition.
In this embodiment, therefore, information is obtained in addition to that provided by condition satisfaction itself or, when a curve is described, the course of the curve in relation to the measurement signal parameter signal (MS-PS) diagram, thereby increasing the possibility of attaining reliable identification of various conditions in the heart.
Alternately, or as an additional complementary feature, the device may include a second timer to measure the time elapsing from a time at which the relevant values satisfy a first specific condition until they satisfy a second specific condition.
In a further embodiment, the device includes a pulse generator for generating and emitting stimulation pulses to the heart according to the state of the heart as analyzed by the device.
The device can thereby supply a therapeutic measure when necessary, such as a specified pacing, antitachycardia or defibrillation sequence.
DESCRIPTION OF THE DRAWINGS
FIG. 1 shows, in block diagram form, an embodiment of the device according to the invention.
FIG. 2 shows a spontaneous heart signal and a stimulated heart signal.
FIG. 3 is a schematic illustration, for explaining the operation of the invention.
FIG. 4 shows a block diagram of a comparator unit in the device.
FIGS. 5 and 6 illustrates state sequences arising in the device of the invention for two different heart sequences.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
An embodiment of the invention in the form of a pacemaker 1 is shown in FIG. 1 is connected to a heart 7. A tip electrode 3 and a ring electrode 4 are placed in the right ventricle of the heart 2 and are connected, via a first electrode conductor 5 and a second electrode conductor 6 to a pulse generator 7 in the pacemaker 1. The pulse generator is also connected to pacemaker can 20 which functions as an indifferent electrode, i.e., the pulse generator 7 can either emit stimulation pulses between the tip electrode 3 and the ring electrode 4 or between the tip electrode 3 and the pacemaker can 20. A detector 8 is connected in parallel with the first electrode conductor 5 and the second electrode conductor 6. The detector 8 senses the heart's electrical activity, i.e., the ECG, and sends a measurement signal to a signal shaper 9. The signal shaper 9 first filters the signal in a bandpass filter 10. The bandpass filter 10 primarily eliminates high frequency noise which could otherwise overwhelm subsequent signal components. After filtration, the filtered signal is sent to each of an amplifier 11, a differentiator 12 and an integrator 13 which integrates the signal for a plurality of heart cycles. In this manner, three parameter signals are formed from the single measurement signal. The signal shaper 9 contains a reference generator 14 which generates a reference signal. The reference generator 14 is connected to pacemaker electronic circuitry 15 which includes e.g., a battery and microprocessor for controlling the pacemaker.
The four signals, at least two of which constitute coordinates forming a curve in a coordinate system, are sent to a comparator unit 16. The comparator unit 16 comprises a plurality of comparators representing different lines in the coordinate system. Each comparator generates an output signal when the curve is on a specific side of the line the comparator represents. So a plurality of output lines X1, X2, . . . , Xn runs from the comparator unit 16 to a sequence analyzer 17 which identifies those comparators which emitted an output signal and the sequence in which this occurs. A plurality of sequence signal lines Y1, . . . , Ym runs from the sequence analyzer 17 to pacemaker electronic circuitry 15, in which the microprocessor decides whether any action should be taken on the basis of the signal from the sequence analyzer 17.
A physician can, with the aid of a programming unit 19 communicate with pacemaker electronic circuitry 15 via a telemetry unit 18, in order e.g., to change the lines the comparators in the comparator unit 16 represent or in order to retrieve stored information on detected sequences and the treatment given.
FIG. 2 shows an example of two different signals which can be detected in the pacemaker 1. A spontaneous heart signal 25 is shown at the top. Here, the spontaneous heart signal 25 only shows the QRST complex in the heart signal 25, i.e., the signals generated by ventricular depolarization in systole and repolarization in diastole.
A stimulation pulse 26, resulting in a stimulated heart signal 27, is shown at the bottom. Again, only the ventricular signal is shown. As a direct comparison shows, the stimulated heart signal 27 lacks the positive R wave found in the spontaneous heart signal 25, while the negative part of the stimulated heart signal 27 is simultaneously more pronounced than the S wave in the spontaneous heart signal 25. The repolarization wave in the stimulated heart signal 27 is larger than the T wave in the spontaneous heart signal 25.
In FIG. 3, the proportional value is plotted against the derivative for each point in time. The spontaneous heart signal 25 then generates the curve 30 and the stimulated heart signal 27 generates the curve 31.
The signal lines represented by the comparators have also been entered into the coordinate system. The comparators will be described in greater detail in conjunction with FIG. 4. As can be seen, the morphological difference between the spontaneous heart signal 25 and the stimulated heart signal 27 is depicted with greater clarity in the PD-coordinate system than in the real time diagrams in FIG. 2.
As noted above, the comparator unit 16 contains a plurality of comparators. FIG. 4 shows one way of constructing the comparator unit 16 With four comparators 32, 33, 34, and 35, four different limit conditions are created which respectively correspond to lines 45, 46, 47, and 48 in the PD diagram in FIG. 3. Input signals to the comparator unit 16 consist of the proportional signal in signal line 36, the integrated signal in signal line 37, the reference signal in signal line 38 and the derivative signal in signal line 39. In the first comparator 32, the proportional signal is supplied to the negative input via a first resistor 40a. The integrated signal is also supplied via a potentiometer 41a, to the negative input. The derivative signal, via a second resistor 40b, and the reference signal, via a second potentiometer 41b are supplied to the positive input. The output signal from the first comparator 32 has been designated X1, and the following conditions must be satisfied for the first comparator 32 to emit an output signal:
D+(C.sub.b ·V.sub.ref)-P-(C.sub.a ·I)>0,
wherein the proportional signal is generally designated P, the derivative signal is generally designated D, the integrated signal is generally designated I, the reference signal is generally designated V ref , the resistors 40a, 40b, etc. all have the same value set at one, and the potentiometers' value in relation to the resistors is designated C a for the first potentiometer 41a, C b for the second potentiometer 41b, etc.
Thus, the first line can be written:
D=P+C.sub.a I-C.sub.b V.sub.ref,
which produces the line 45 in the PD diagram in FIG. 3. The first comparator 32 generates an output signal when the curve 30 is above the line 45.
In the corresponding manner, the proportional signal is connected, via a resistor 40c and a first inverter 43a, to the negative input in the second comparator 33. The integrated signal is also connected, via a third potentiometer 41c and the first inverter 43a, to the negative input. The derivative signal, via a fourth resistor 40d, and the reference signal, via a fourth potentiometer 41d are supplied to the positive input. The output signal from the second comparator 33 has been designated X2, and the condition
D+C.sub.d V.sub.ref -(-P-C.sub.c I)>0
must be satisfied for an output signal to be received from the second comparator 33, i.e., the line D=-P-C c I-C d V ref . This is line 46 in the PD diagram.
For the comparator 34, the proportional signal is analogously connected to the negative input, via a fifth resistor 40e and a second inverter 43b, and the integrated signal, via a fifth potentiometer 41e and the second inverter 43b. The derivative signal via a sixth resistor 40f, and the reference signal, via a sixth potentiometer 41f are supplied to the positive input. Output X3 from the third comparator 34 produces an output signal when the curve is above line 47 in the PD diagram.
The fourth comparator 35 has its negative input connected to virtual ground 42, and to the positive input are connected the derivative signal, via a seventh resistor 40g and the reference signal, via a seventh potentiometer 41g. The output X4 produces an output signal when the curve is above line 48 in the PD diagram.
As shown by the curves in the PD diagram in FIG. 3, the spontaneous curve 30 encloses both a first point 49 at the intersection of lines 45 and 46 and a second point 50 at the intersection of lines 45, 47 and 48, whereas the stimulated signal 31 only encloses the second point 50. A determination by the sequence analyzer 17 of whether the generated curve encloses both the first point 49 and the second point 50 is sufficient to distinguish spontaneous heart signals from stimulated heart signals and to determine whether the signal is spontaneous or stimulated.
More generally, the areas formed between the lines 45, 46, 47 and 48 can be said to represent different states of the device, since the combination of output signals from the comparators 32, 33, 34 and 35 are unique to each area. If, for example, starting from the origin in the PD diagram conditions for emission of a signal by the first comparator 32, the third comparator 34 and the fourth comparator 35, respectively corresponding to lines 45, 47, and 48, are satisfied, this results in a signal state of 1011 for signal outputs X1, X2, X3, X4. If each state described by a curve is recorded, a number of different heart conditions can be identified. The function of the sequence analyzer 17 can thereby be described with state sequence graphs, as shown in FIGS. 5 and 6.
FIG. 5 shows eight states, corresponding in principle to the states which can occur in the above-described embodiment. The intersection of lines 46 and 48 (not shown) results in an additional area and state which is not shown in the FIG.
The spontaneous curve shown in FIG. 3 will commence in state 1011 in the sequence graph, then cross line 46 to state 1111 and then, after crossing line 45, to state 1101, etc., traversing the entire sequence back to state 1011.
FIG. 6 shows the sequence between states covered by the stimulated signal 31. It also begins in state 1011 but subsequently crosses line 45 and goes directly to state 1011, thereafter following the same sequence as the spontaneous signal 30.
On the basis of the possible sequences a signal is able to follow, the sequence analyzer 17 can be devised to identify specific state change sequences, thereafter emitting a signal to pacemaker electronic circuitry 15 in the pacemaker 1. The lines 45 through 48 can be shifted in different ways with the potentiometers 41a through 41g so as to adapt conditions to different patients. Each sequence, or series of changes in state, corresponds to a specific morphology for the input signal, and since morphology changes in different ways in the presence of different heart conditions, such as tachyarrhythmias and extrasystoles, fast and reliable identification of the heart's current condition is achieved. If necessary, therefore, suitable therapy can be instituted immediately. Especially with patients suffering from different types of tachyarrhythmia, a pacemaker with an analyzer according to the invention can easily identify the different types and institute the therapeutic measure most appropriate to the condition in question.
To increase reliability in the identification of different heart conditions, the sequence analyzer 17 can be equipped with a timer which measures the time a generated curve is in a specific state.
Since every condition is unique, the sensing of each condition transition is not always necessary; only a few transitions need to be noted as arising in a specific way (e.g., a transition from a specific state or taking a specific amount of time to pass between two specific states), in order for a valid identification of the current heat condition to be made.
Although modifications and changes may be suggested by those skilled in the art, it is the intention of the inventors to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of their contribution to the art. | A device for analyzing the function of a heart has an electrical measurement unit for generating a measurement signal related to an electrical or mechanical heart variable, and an evaluation unit for evaluating the measurement signal. The device further includes circuitry for generating at least one parameter signal from the measurement signal. The evaluation unit analyzes related values in the measurement signal and the parameter signal, these related values corresponding to coordinates which form a curve in a coordinate system, the measurement signal and the parameter signal serving as coordinate axes, by sensing the sequence in which the curve passes a predesignated number of areas in the coordinate system. The device is capable of detecting spontaneous and stimulated heartbeats, tachyarrhythmias, retrograde conduction, ectopic beats, etc. | 0 |
BACKGROUND OF THE INVENTION
Obstructive Sleep Apnea Syndrome Syndrome (OSAS) is a serious medical condition that is difficult to treat easily and effectively. The condition is marked by a partial or complete closure of the upper airway during sleep.
There are four basic therapeutic modalities in the treatment of OSAS: pneumatic splinting of the airway with positive airway pressure (PAP), airway orthotic (AO) which mechanically dilates the upper airway, surgery, and combination therapy which uses an airway orthotic plus positive airway pressure.
PAP acts as a pneumatic splint which literally blows open the upper airway during sleep such that the tendency for the upper airway to collapse is either eliminated or reduced.
There are a variety of surgeries to treat OSAS, some approaches work better than others. Since this is not the subject of this patent, nothing further will be said on this issue.
Combination therapy typically utilizes mechanical or physical tissue manipulation of the muscles of the upper airway via use of an AO plus pneumatic splinting of the airway. Alternatively, combination therapy may use an AO without mechanical dilation of the upper airway. When an AO is used without mechanical dilation of the upper airway, the AO may be utilized to stabilize an application device for delivery of PAP with a non-claustrophobic interface and the active treatment then depends solely on pneumatic splinting of the upper airway.
Standard PAP therapy usually includes a nasal application device for delivery of the positive airway pressure to the patient's nasal passages. There are different styles of nasal application devices. These include:
a) Triangular-shaped nasal masks which form a seal surrounding the patient's nose on his facial surface, b) Full-face masks that form a seal on the patient's face around both the nose and mouth, c) Nasal inserts commonly referred to as nasal pillows.
The nasal application device is connected to a Continuous Positive Airway Pressure machine (CPAP) via tubing. These air pressure machines (CPAP) can be set to certain and particular pressure settings. Each patient will have a certain and particular pressure level of PAP that will dilate and pneumatically splint his upper airway. When utilized properly, this therapy is very effective in treating the patient with a nocturnally obstructed airway.
Nasal CPAP is considered to be the gold standard in treatment of moderate to severe OSAS. However, this life saving therapy is fraught with significant compliance problems. Clinical studies indicate that compliance on nasal CPAP is less than 50%. Reasons for this non-compliance are numerous and include problems with mask fit and resultant mask discomfort, mask leakage of PAP, claustrophobia, head gear discomfort, head strap discomfort, sleep position (supine) confinement, mouth venting or leakage, chin strap confinement and discomfort, dermatitis, swallowing of air, pressure-related tolerance issues etc.
Airway Orthotics (AO) are oral appliances that are worn in the mouth at night for the purpose of treating OSAS. Historically, there are two basic types of airway orthotics: the tongue retention device (TRD) and the mandibular advancement device (MAD). For the purposes of this disclosure nothing more will be said about the TRD other than to note its existence.
Most mandibular advancement (MADs) devices mechanically dilate the upper airway by moving the lower jaw, or mandible, forward in controlled increments. The airway is dilated by a combination of: pulling the tongue base anteriorly away from the airway and holding it forward during sleep, tightening of the apneic patient's upper airway via anterior and superior movement of the hyoid bone which stretches the infrahyoid muscles attached to the upper airway, innervation of key airway muscle groups such as the genioglossus, palatoglossus, and inferior bellies of the lateral pterygoid(s), and lateral stretching of the hypopharynx.
Mandibular advancement devices can either be fixed or adjustable. In general, adjustable MADs are preferred by most clinicians who treat OSAS because they may be titrated, or gradually adjusted, according to the patient's airway needs. These MAD devices incorporate a variety of different designs and schemes to move the lower jaw forward.
However, advancing of the mandible can result in unpredictable occlusal (bite) changes. Therefore, the clinician must weigh all possible outcome factors, both positive and negative, in formulating his treatment plan.
Mandibular advancing devices, while often helpful, can complicate issues for the patient undergoing “combination therapy.” Complicating issues can compromise the effectiveness of the therapy by resulting in decreased compliance or utilization. Therefore, there is a need to create simple and effective therapies for OSAS that minimize complications. Often, the effectiveness of nasal CPAP, airway orthotics, or combination therapy relates to patient compliance with the therapy. Simpler, less burdensome therapies will generally lead to higher compliance and resultant efficacy in treatment.
SUMMARY OF THE INVENTION
The objectives of this invention are to improve on the concept of combination therapy for OSAS based on several factors.
1) Simplifying the use by the patient to increase compliance through minimization of necessary parts in design of the airway orthotic; 2) Accommodation of varying nare-to-nare and nose widths for use of nasal pillows and tubing; 3) Obturation of the oral cavity preventing mouth venting of PAP without the need for a chin strip or need to add a separate piece known as a “vent or saliva shield;” 4) Use of a 3 mm minimum thickness of acrylic for PAP Tubing Retention Platform construction to improve strength, integrity and malleability to customize tubing angulation via application of heat. Usually this heat is applied by a micro torch; 5) Improving angulation of nasal tubing by closest preferred approximation anterio-posteriorly to positions directly below the nares. 6) Minimization of occlusal changes in utilization of airway orthotics by building these oral appliances in a neutral-centric mandibular position with no mandibular advancement such that the mandible is in centric relation, centric occlusion or the like.
Design of Airway Orthotic
This invention will introduce a new type of airway orthotic that will simplify insertion, usage, and increase effectiveness for the patient. This airway orthotic serves three primary functions:
a) to obturate or seal off the oral cavity preventing mouth breathing and/or mouth venting of positive airway pressure (PAP); b) to support application of PAP via nasal pillows directly from the obturator without use of any headgear, straps or chin support to stabilize the nasal seal during movements at night. c) to hold the upper and lower jaws in a preferred position via use of an elastomeric material without the use of a hook, chin stabilizer, or strap.
Method of Manufacture
1) Individual impressions are made of the upper and lower teeth and master casts are poured in stone or plaster.
2) A bite registration is also recorded which documents the relationship of the mandible to the maxilia in three dimensions and is used by the laboratory to mount the upper and lower casts on an articulator. The bite registration position may be captured either:
a) In neutral centric position, i.e., without mandibular protrusion/advancement; or, b) In a protruded position referred to as mandibular advancement; and c) May vary the caudal or vertical component to make room for the tongue and/or maximize patency of the airway.
3) The airway obturating orthotic is professionally manufactured in the laboratory and is composed of a hard acrylic exterior which is lined with an elastomeric material such that there is a snap fit when the upper and lower teeth are engaged into it. This snap fit via said elastomeric material holds the lower jaw in preferred position without any additional means. Elastomeric materials flex like rubber when pressure is applied as in the case wherein teeth snapfit over the internal surfaces of the appliance.
The following passages will now compare the present invention with prior art specifically referenced to illuminate useful and novel differences between the present invention and the prior art.
By way of reference I direct the reader to U.S. Pat. No. 6,209,542, entitled “Combination face mask and dental device for improved breathing during sleep.” Dr. Thornton describes an apparatus consisting of a face mask connected to an oral appliance. The adjustment means allows for positioning of the mask from a first to a second position. The patent describes an oral appliance that has separate upper and lower arch components.
Goldstein U.S. Pat. Nos. 5,752,510 and 6,012,055 teaches of a dual-arch mandibular advancement device that incorporates application of a nasal mask and nasal inserts.
By comparing the referenced prior art the reader will note fundamental differences between the present invention and what is taught by Thornton and also Goldstein.
The airway orthotic or oral appliance in the present invention is intentionally non-adjustable. By utilizing a fixed/non-adjustable appliance the apnea patient avoids the complication of:
a) first inserting the upper arch and then the lower arch and: b) then hooking them together.
For certain patients, like those patients with a significant mental or developmental impairment or impairment through aging, this joining together of individual components can be challenging. This challenging problem alone can lead to non-compliance and subsequent failure of the therapy.
With the present invention, the patient simply opens his mouth and bites down with the upper and lower teeth simultaneously onto a one-piece, dual arch orthotic in one clean motion. This fixed orthotic contains both the upper and lower arches in one unit lined with an elastomeric material. This simplicity is preferable because it will increase compliance on the therapy, which increases overall effectiveness medically.
There is the problem referred to as mouth venting of PAP. This is where air is blown into the nose and the patient inadvertently opens his mouth while asleep and thereby permits air to be blown out of his mouth, via path of least resistance. This occurs due to insufficient obturation or sealing-off of the oral cavity. This results in inadequate requisite, therapeutic pressure requirements when PAP is required to effectively open or pneumatically splint a patient's upper airway.
With the two-piece, separate component design, as taught by Thornton, there is a significant space between the upper and lower arches. Unfortunately, this allows for PAP to escape at night when the patient is asleep which results in lowering of therapeutic pressure. Attempts to correct this problem with prior art have included adding a chin strap and/or a separate, extra component referred to as a “vent or saliva shield.” This vent shield must be added to the multi-component device complicating utilization by patients.
The present invention has no need for a chin strap or a separate vent shield to prevent leakage of requisite PAP. This problem is solved by sealing the upper and lower arches with acrylic to form a PAP obturator. There is no unsealed space between the upper and lower components anteriorly of the airway orthotic from which PAP can escape. Some space posteriorly may be intentionally left open for tongue room without compromising obturation because the tongue will fill the void laterally and complete the obturation. The snap fit of the teeth produced by the elastomeric material obviates the need for a chin strap or similar means to keep the mouth closed at night when PAP is blown into the nasal passages.
Advancing the mandible to correct OSAS can result in untoward occlusal changes or changes in the patient's bite. This occurs from significant orthodontic forces being applied to teeth due to intentional forward positioning of the mandible by using the maxillary teeth as an anchor or fulcrum to lever the mandible forward which results in muscles applying undesirable forces upon teeth at night.
The present invention solves this problem by placing the patient's lower jaw in a neutral centric position to minimize or eliminate orthodontic forces on the teeth where there is clinical indication to do so. However, the present invention may utilize mandibular advancement in the design when there may be some benefit to do so. The only reason to advance the mandible in combination therapy would be an attempt to reduce unreasonably high therapeutic PAP pressure if this factor is reducing patient compliance on nasal CPAP.
Means of application of PAP via the Thornton (combination) invention referred to as the “TAP/SAAMS” uses a one size fits all noses, tubing retention platform (SAAMS). In clinical practice this is very problematic as nose and nare widths vary widely. Without adjusting the width laterally of the PAP Tubing Retention Platform, many patients will fail this type of combination therapy. Thornton's art does not anticipate the use of variable nose-width tubing retention platforms, nor is it obvious to those skilled in the art.
The present invention incorporates a method whereby the PAP Tubing Retention Platform is varied in lateral width to accompany the varied width of patient noses and nares. Different sizes in lateral widths of PAP Tubing Retention Platforms permit proper angulation and placement of nasal tubing carrying PAP. Proper angulation and placement of PAP Tubing results in a profound and stabile seal of PAP at the nares.
The present invention seeks to overcome prior art design that is fraught with another very significant problem as concerns proper angulation of nasal tubing to deliver PAP. This problem is that often the SAAMS platform is simply too far away, anterior-posteriorly, from the patient's nasal passages to approach the nares from a preferred angle. This is because the TAP/SAAMS design attaches or fits directly over the “Front Assembly” utilizing a Sheath Slide Extension. The anterior end of the Front Assembly, where the Adjustable Advancement Nut lies, is normally at least 22 mm from the labial surface of the maxillary anterior teeth. When the SAAMS tubing retention platform is added/screwed into place on top of the Front Assembly via the Sheath Extensions, the PAP nasal tubing is at least 35 mm from the labial surface of the maxillary anterior teeth. This design flaw forces the clinician to angulate the nasal tubing in an undesirable manner often resulting in failure to properly seal the nares and maintain the seal while the patient is asleep.
The present invention allows the PAP Tubing Retention Platform to slide posteriorly to preferred positions which are much closer to the patient's nares. This allows for preferred positioning and angulation of PAP nasal tubing thereby improving the requisite seal at the nares and thereby increasing success in treatment. The present invention allows for the PAP Tubing Retention Platform to achieve proximity to the labial aspect of the maxillary anterior teeth in a range of 5 mm to 30 mm depending on the patient's anatomy.
In addition to moving the PAP Tubing Retention Platform posteriorly on the Variable Length Slide to achieve proximity of PAP Tubing directly below the nares, the present invention recognizes additional means to assist in solving this problem. First, the PAP Tubing Retention Platform may be “U” shaped a the posterior end of the Platform such that the PAP Tubing Holes swing backward on the left and right sides toward the patient's face. Second, the adjustable Slide Mount Bracket may be mounted anterior to the posterior edge of the PAP Tubing Retention Platform allowing the Platform to get closer to the patient's face.
The present invention also envisions a method of changing the Thornton design whereby this limitation in design, which prevents close approximation of the PAP Tubing Retention Platform to more closely approximate access to the flares, is overcome. By removing the Adjustable Advancer Nut and inserting a female threaded stainless steel sleeve into the posterior section of the Front Assembly, a new Sheath Extension can be fit over this remaining section of the Front Assembly to bring a SAAMS' PAP Tubing retention platform closer to the preferred position underneath the patient's nares. Alternatively, a new Front Assembly could be designed without the Adjustable Advancer Nut that includes a built-in PAP Tubing Retention Slide that could be directly screwed into the Locator Plate allowing closer approximation of the PAP Tubing Retention Platform posteriorly. This would allow the current TAP/SAAMS user to add PAP and reduce distance from the nares by at least 8 mm. This would significantly improve the combination therapy described by Thornton.
The “TAP/SAAMS” design incorporates a metal component termed the “Locator Plate” which is imbedded within the anterior shell of acrylic in the upper arch component of the TAP device. The Front Assembly with Adjustable Advancer Nut is screwed into this Locator Plate via the Locator Nut Set. On top of this is the platform Sheath Extension that in turn screws onto the end of the Adjustable Advancer Nut. Because the Locator Plate is imbedded into the acrylic it can sustain excessive forces due to levering action of the Sheath Extension Slide such that there is a tendency for fracture of the acrylic at the anterior surface of the upper component of the MAD.
The present invention has no metal parts imbedded within the acrylic of the airway orthotic. The PAP Tubing Retention Platform Slide is bonded, injection molded, or cast in acrylic and thereby attached to the single piece, dual arch obturating airway orthotic. All exterior components are made from acrylic and bonded together. This greatly reduces potential for fracture. Additionally, in the present invention the length of the PAP Retention Platform Slide may be cut once the patient is fitted thereby reducing lever arm forces. This is not possible with the Thornton invention without irreparably damaging it.
This invention also seeks to improve on another nasal insert/pillow pressure application structure device known as the “Adam Circuit.” The Adam Circuit is a headgear device sold by Puritan-Bennett Corp. (Pleasanton, Calif.) under the trademark “Breeze” that attempts to stabilize the use of nasal pillows. However, this device described in U.S. Pat. No. 4,782,832 utilizes an uncomfortable and cumbersome headgear to support the sealing of the patient's nares with PAP. This device has a significant tendency to become displaced when a patient moves around in his bed at night or simply shift to his side. When this device is in contact with his bed-pillow the seal at the nares is often broken thereby reducing the requisite therapeutic pressure prescribed to open the patient's upper airway. The present invention utilizes nasal pillows but improves on the method of stabilization of the seal of the nares and avoids the uncomfortable and cumbersome headgear.
In reference to U.S. Pat. Nos. 5,752,510 and 6,012,455 (Goldstein) there are novel and useful differences between the prior art and the present invention.
Goldstein describes an oral appliance that produces a double bite and uses PAP in combination. But there is no intent to obturate the oral cavity and the reason for Goldstein's dual arch is for a different purpose and his method of design and manufacture is quite clearly different than the present invention. The astute reader will note that the differences in the present invention are novel and useful as compared to Goldstein.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the present invention utilizing a single-piece, dual arch, obturator with an acrylically-connected slide upon which moves an adjustable PAP Tubing Retention Platform device.
FIG. 2 a shows the PAP Tubing Retention Platform adjacent to a small nare and nasal width.
FIG. 2 b shows the PAP Tubing Retention Platform adjacent to a medium nare and nasal width.
FIG. 2 c shows the PAP Tubing Retention Platform adjacent to a large nare and nasal width.
FIG. 3 shows a superior view of the dual arch, obturating airway orthotic with anterior supported for an array of varying width PAP Tubing Retention Platforms. Only one size PAP Tubing Retention Platform is shown in this figure.
FIG. 3 a is a tor view of the PAP Tubing Retention Platform.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows a lateral view of the present invention. This view in from the patient's right side where the Upper Right Quadrant 1 is superior and the Lower Right Quadrant 2 is inferior. Posteriorly there is Tongue Space A just where the Solid Acrylic Obturating Seal 8 ends. Typically the Solid Acrylic seal will extend to at least the mesial aspect of the maxillary first molar if not slightly further to create the most robust seal. The Upper Dental Arch 5 is superior to the Lower Dental Arch 6 . The airway orthotic is composed of Exterior Hard Acrylic 7 and is lined interiorly with Elastomeric Material 4 . Anteriorly the 5 mm Slide Mount 16 is operatively connected to the Variable Length Slide 13 . Upon the Variable Length Slide the Variable Width PAP Tubing Retention Platform 12 is adjustably affixed to the Variable Length Slide via the Slide Mount Bracket 14 . Superiorly and anteriorly there is a Nasal Pillow 9 which fits over a Collar 10 . The Collar inserts into the PAP Tubing 15 which is threaded through the Variable Width PAP Tubing Retention Platform via the PAP Tubing Hole ( FIG. 3 , 18 ). At a certain preferred distance from the nose inferiorly is a Whisper Swivel II Valve (Respironics Part Number 332113). Above the Whisper Swivel II Valve and within the PAP Tubing is located an optional Exhaust Port 11 . Both the Whisper Swivel II Valve and the Exhaust Port are utilized to blow off or vent Carbon Dioxide (CO2) on patient exhalation. The rate of expiratory flow from use of these structures is between 5-15 liters per minute. The need for the optional Exhaust Port can be determined in the sleep laboratory by end tidal CO2 monitoring. If the patient is retaining too much CO2 PAP Tubing Holes are created to assist the Whisper Swivel II Valve in blowing off excess CO2.
FIG. 2 shows the Present Invention whereby a method of treating Obstructive Sleep Apnea Syndrome utilizes PAP Tubing Retention Platforms that are variable in widths to correspond with variations in nasal and nare width. FIG. 2 shows three hypothetical patient nasal widths small, medium, and large that correspond with particular width PAP Tubing Retention Platforms (small 12 a , medium 12 b , and large 12 c ). The reader will note that there could be additional Platforms as necessary to accommodate any and all variations in patient nasal widths. If there is flaring of the nares superiorly the PAP Tubing Retention Platforms may be increased slightly in width to allow for angulation medially of the Platform via application of heat to bend the acrylic so as to customize the angular approach of the PAP Tubing 15 . The preferred thickness of the Variable Width PAP Tubing Retention Platforms should be at least 3 mm. These PAP Tubing Retention Platforms can be manufactured via standard methods such as heat “suck-down” whereby a 3 mm sheet of acrylic such as Biocryl is heated until pliable and vacuum-formed onto various width molds forming the preferred structures. They may also be injection molded or cast directly in acrylic via the lost wax technique. The PAP Tubing Retention Platform is mounted onto the Slide 13 via the Slide Mount ( FIG. 1 ) and can be preferably located or adjusted as close as 5 mm from the labial surface of the anterior teeth. The preferred range of location of the PAP Tubing 15 will be 5 mm to 30 mm from the labial surface of the maxillary anterior teeth. Once the preferred location anterio-posteriorly is located for the individual patient the Slide 13 may be cut to reduce unnecessary lever arm forces.
FIG. 3 shows the present invention in a superior view and FIG. 3 a is a tor view of the PAP Tubing Retention Platform 12 . The Variable Width PAP Tubing Retention Platform 12 is shown in two widths and styles in this figure and is mounted onto the Variable Length Slide 13 via the Slide Mount Bracket 14 . The first style is rectangular and the second style is “U” shaped. There are two PAP Tubing Holes 18 which correspond to the right and left nares in both styles. The width of the PAP Tubing Retention Platform and position of the holes is preferably selected to match the corresponding width of the patient's nasal and nare width. The Solid Acrylic Obturating Seal 8 continues from the anterior region of the airway orthotic posteriorly as necessary to seal off the oral cavity from loss of requisite therapeutic positive airway pressure as determined in the sleep laboratory. There is Tongue Space A anteriorly, laterally, and vertically. The vertical or caudal dimension of the airway orthotic is varied according to tongue size and is determined by the experienced clinician through a variety of means or methods. The preferred embodiment utilizes a neuromuscular TENS (Transcutaneous Electrical Nerve Stimulation) technique whereby the masticatory muscles are profoundly relaxed to proper working lengths via this pulsing technique placing the mandible in three dimensional harmonious space position with respect to the maxilla. In this manner the mandibular position anterio-posteriorly (AP) and vertically is determined by the muscles themselves rather setting an arbitrary position. This neuromuscularly-determined position is referred to earlier in the specification as “neutral centric” position. If the need presents, due to excessive therapeutic PAP requirements for an individual patient, the AP position of the mandible may be somewhat protruded forward so as to create some mechanical dilation of the upper airway. However, this forward positioning of the mandible will increase the risk of a deleterious change in the patient's occlusion or bite. Therefore, the preferred position will typically be the neutral centric position as determined by the experienced clinician.
The foregoing description of the preferred embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Accordingly, the foregoing description should be regarded as illustrative rather than restrictive, and it should be appreciated that variations may be made in the embodiments described by workers skilled in the art without departing from the scope of the present invention as defined by the following claims. | The invention describes a method for treating Obstructive Sleep Apnea Syndrome (OSAS) utilizing positive airway pressure (PAP) by creating a single-piece, dual arch airway orthotic, using said orthotic to obturate the oral cavity via an acrylic seal between the upper and lower dental arches, retaining the upper and lower dental arches in elastomeric material via a snap-fit and applying PAP via the nasal passages from tubing which is supported from said airway orthotic. | 0 |
BACKGROUND
These teachings relate generally to MEMS optical switches.
Optical switches are devices that route optical signals along selected fibers of an optical network. Such switches constitute the fundamental building blocks of modern optical networks. Prior art optical switches are primarily based on mechanisms that perform mechanical movements, change waveguide coupling ratios, and perform polarization rotations. Mechanical relay based optical switches has large size. Considerable interest has been shown in MEMS technology for its small size. Among them, MEMS electrostatic rotating mirror based devices are one of most common approaches. However, their need for a high electrical field to generate sufficient actuation force results in the requirement of costly hermetic packaging. Furthermore, they are non-latched and switch states are lost when external electric power is lost. A bistable mechanism using electro-thermal actuation is also used for optical switches. However, those devices use an in-plane actuation for a vertical etched mirror, leading to costly fabrication and small depth mirror size.
Therefore, there is a need for an improved MEMS switch design that is small in size, ultra-stable, latching, low cost and easy to manufacture, scalable to multiple output ports.
BRIEF SUMMARY
One embodiment of the optical switch of these teaching includes a bistable component comprising one or more first beams and one or more second beams, a reflective component; the one or more first beams extending from a first support to a location on the reflective component, the one or more second beams extending from a second support to the location on the reflective component, the reflective component being operatively connected to the bistable component, a first electrothermal bent beam actuator component extending from a first electrode to a second electrode, a first contacting component operatively connected to the first electrothermal bent beam actuator component, the first electrothermal bent beam actuator component and the first contacting component disposed such as to enable advancing the bistable component the reflective component from a first stable configuration to a second stable configuration, a second electrothermal bent beam actuator component extending from a third electrode to a fourth electrode and a second contacting component operatively connected to the second electrothermal bent beam actuator component, the second electrothermal bent beam actuator component and the second contacting component disposed such as to enable advancing the bistable component and the reflective component from the second stable configuration to the first stable configuration.
Values other embodiments of the optical switch of these teachings are also disclosed.
Embodiments of the method of operation of the optical switch of these teachings and embodiments of methods for fabricating the optical switch of these teachings are also disclosed.
For a better understanding of the present teachings, together with other and further objects thereof, reference is made to the accompanying drawings and detailed description and its scope will be pointed out in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic representation of one embodiment of the optical switch of these teachings;
FIGS. 1 a and 1 b are schematic representations of another embodiment of the optical switch of these teachings.
FIG. 2 is a graphical representation of displacement-force relationship in a bistable component in one embodiment of the optical switch of these teachings;
FIGS. 2 a and 2 b show an optical system utilizing embodiment of the optical switch of these teachings;
FIG. 3 is a schematic representation of yet another embodiment of the optical switch of these teachings;
FIGS. 4 a and 4 b are schematic representations of embodiment of one component of the optical switch of these teachings; and
FIGS. 5 a - 5 e are graphic illustrations of an embodiment of a process for manufacturing devices of these teachings.
DETAILED DESCRIPTION
The following detailed description is of the best currently contemplated modes of carrying out these teachings. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of these teachings, since the scope of these teachings is best defined by the appended claims.
In one embodiment, the present teachings overcome the above problems by providing an optical switch that uses one or more elements of micro-electro-mechanical system (MEMS) devices aligned with one or more fiber collimators to steer light beams from one or more input ports to one or more output ports. In that embodiment, a MEMS chip has an in-plane optical reflective component (such as, but not limited to, a mirror) suspended on a self-latching bistable mechanism, and two electrothermal actuator components. The actuators drive the bistable mechanism from its first stable position to its second stable position and from its second stable position to its first position. Thus, the suspended mirror directs the light beam in a plane that is perpendicular to the plane of the MEMS device to different output ports at different stable positions through either transmission or reflection of the light beam.
In one embodiment of the present teachings, the above and the optical switch includes a MEMS bistable mirror configuration comprising a frame having a planar surface, two MEMS actuators that drive the reflective mirror in the planar surface to its stable positions to steer light beam transmitting from sources of electromagnetic radiation such as, but not limited to, optical fibers.
In one embodiment, the reflective mirror surface is suspended by multiple identical paralleled bistable mechanisms, which constraint the motion of mirror in the plane of the mirror surface.
In one embodiment of the bistable mechanism formed by curved beam segments arranged symmetrical to the suspended mirror and anchored at an outer frame.
In one embodiment, each actuator component is formed by multiple electrothermal parallel V-beams with optimal displacement output.
In one embodiment, each set of actuators has one center or multiple contact surfaces along the bistable mechanism to push the mirror to different stable locations. When multiple contact surfaces are used, different contact surfaces may have different time sequence to contact. This can decrease the mechanical wear on each contact surface to increase contact cycle life. The off-center actuations can also increase travel distance of the mirror.
In one embodiment, the one or more contact surfaces have a flexible surface and a hard surface to form a self-contact when contact force applied. This can decrease contact force on each surface therefore increase contact life time. When different contact surfaces have different time sequences, the contact duration can be further enhanced.
In one embodiment, the mirror position can be detected through resistance change of the components of the bistable mechanism (silicon wire in one embodiment) due to a change in the strain of the bistable mechanism. At this first stable position, the bistable mechanism has substantially no strain while at the second stable position, strain is developed.
In one embodiment, the mirror position can be detected through capacitance change due to gaps between the contact surfaces changes at each stable position.
In one embodiment, the MEMS fabrication steps are simplified by using only a few steps with a minimum number of masks using silicon on insulator (SOI) wafers.
FIG. 1 illustrates a schematic view of an embodiment of a MEMS bistable optical switch chip. The MEMS bistable optical switch chip 1 includes a substrate 49 (embodiments in which the bistable optical switch chip is lifted from the substrate are also within the scope of these teachings) having a planar surface frame 16 , a reflective mirror 2 arranged on the planar surface 16 , a bistable mechanism 3 formed by two curved beams 4 and 5 and symmetrical to the center of the mirror 2 ; two electrothermal actuators 6 and 11 . The bistable mechanism 3 suspends the mirror 2 on the frame 16 . Multiple identical, paralleled bistable mechanisms 3 are used to restrict the motion of the mirror in the plane 16 along the symmetric axis of the bistable mechanism or Y axis. Typical displacement-force relationship of the bistable mechanism is shown in FIG. 2 . The two stable positions are as labeled in the plot. Each stable position has a maximum break force as labeled in FIG. 2 .
A number of possible embodiments of the bistable mechanism are within the scope of these teachings. Embodiments such as, but not limited to, those disclosed in U.S. Pat. No. 6,911,891, issued to Qui et al., which is incorporated by reference herein in its entirety for all purposes, and the embodiments disclosed in Jin Qiu; Lang, J. H.; Slocum, A. H., A curved-beam bistable mechanism. Journal of Micro-electromechanical Systems, April 2004, Vol. 13, Issue 2, pp. 137-146, Casals-Terre, J., Shkel, A., Dynamic Analysis Of A Snap-Action Micromechanism, 2005 IEEE Sensors, 2005, and Youngseok Oh, Synthesis of Multistable Equilibrium Compliant Mechanisms, Ph. D. Thesis, Univ. of Michigan, 2008, all of which are incorporated by reference herein in their entirety for all purposes, are within the scope of these teachings.
Electrothermal actuator 6 is used to switch the bistable mechanism from first stable position to second stable position, or the mirror 2 from the first stable position to the second stable position. Electrothermal actuator 11 is used to switch the bistable mechanism from second stable position to first stable position, or the mirror 2 from the second stable position to the first stable position. Actuator 6 has a multiple identical paralleled V-beam wire structure 54 , force and displacement translation beam 7 , and contact surfaces 8 , 9 and 10 (the force and displacement translation beam 7 , and contact surfaces 8 , 9 and 10 are one embodiment of a first contacting component and the force and displacement translation beam 12 , and contact surfaces 13 , 14 and 15 are one embodiment of a second contacting component) to interact with bistable mechanism 3 . Note a single contact surface 9 can be used for actuation and is covered by this patent. The actuator 6 has two electrodes 37 and 38 are on the frame surface 16 . When a voltage different applied on electrodes, a driving electric current will apply to the wires (beams) 54 of the actuator 6 , the wires 54 and contact surfaces 8 , 9 and 10 will move along Y-axis to close to the bistable mechanism 3 and mirror 2 . The contact forces at those contact surfaces will push the bistable mechanism 3 and mirror 2 to its second stable position. The multiple surfaces 8 , 9 and 10 have different time sequence to engage with the bistable mechanism 3 and mirror 2 with 9 first and then 8 and 10 . This different time contact sequence can greatly reduce mechanical wear at each surface therefore increase switch cycle life. Off-center contact surface 8 and 10 can also increase the travel distance of the mirror 2 , and, therefore, increase mirror size.
In the embodiment shown in FIG. 1 , the actuator 11 has multiple V-beam (also referred to as “bent beam”) wire (beam) structure 53 . When a current is applied the wires 53 through electrodes 41 and 42 which are on the surface 16 , the center of the wires 53 will move the contact surfaces 13 , 14 and 15 close to the mirror 2 and bistable mechanism 3 . The contact forces will move the bistable mechanism 3 and the mirror 2 from the second stable position to the first stable position. The multiple contact surfaces 13 , 14 and 15 are used to decrease mechanical wear, increase contact duration and travel distance of the mirror 2 along Y-axis.
A variety of bent beam actuators are within the scope of these teachings. Actuators such as, but not limited to, those disclosed in U.S. Pat. No. 6,853,765, to K. Cochran, and in Long Que et al., Bent-Beam Electrothermal Actuators-Part I: Single Beam and Cascaded Devices, Journal of Microelectromechanical Systems, Vol. 10, NO. 2, June 2001, both of which are Incorporated by reference herein in their entirety for all purposes. Actuators that are not bimetallic actuators are within the scope of these teachings
With mirror size along Y-direction equal or less to the (largest) travel distance of the bistable mechanism along the Y direction (the distance travelled by the mirror in the direction substantially perpendicular to the contact surfaces), when light beams in the plane perpendicular to the plane 16 with light beam sizes equal or smaller to the mirror size, the mirror 2 can completely block the light beam and steer the light beam to different directions at one stable position while let the light beams continue propagate in the original direction without effect at the other stable position. Multiple light beams with such MEMS chips can be used to form a switch with multiple input ports and multiple output ports.
The stable positions of the mirror 2 can be detected by the intrinsic strain gage properties of the bistable mechanism 3 . At the first stable position, the bistable mechanism has substantially no strain while at second stable position, a large strain is developed. Therefore, by measuring the resistance change between the electrodes 39 and 40 , the positions of the mirror 2 can be detected. An another embodiment of the method to detect the mirror 2 positions is to detect the capacitance change at electrodes 37 and 39 or 39 and 41 due to the gap changes between the contact surfaces at different stable position.
In another embodiment, shown in FIGS. 1 a and 1 b , the bistable mechanism 3 is comprised of two curved beams ( 83 , 84 ) and each bent beam actuator 6 , 11 has one beam comprised of two parts ( 60 , 65 for the first bent beam actuator 6 , 75 , 70 for the second bent beam actuator 11 ). In the embodiment shown in FIGS. 1 a and 1 b , the first contacting component 81 has a single contact surface 85 and the second contacting component 89 has a single contact surface 87 . FIG. 1 a shows the bistable component 3 in a first stable configuration and FIG. 1 b shows the bistable component 3 in the second stable configuration.
In yet another embodiment, shown in FIG. 3 , the MEMS bistable optical switch 17 includes a substrate 50 (embodiments in which the bistable optical switch is lifted from the substrate are also within the scope of these teachings) having a planar surface frame 17 , a reflective mirror 18 arranged on the planar surface 17 , a bistable mechanism 19 suspending the mirror 18 to frame 17 . Multiple identical, paralleled bistable mechanisms 19 are used to restrict the motion of the mirror in the plane 16 along the symmetric axis of the bistable mechanism or Y axis.
Electrothermal actuator 22 is used to switch the mirror 18 from its first stable position to its second stable position. Electrothermal actuator 27 is used to switch the mirror 18 from its second stable position to its first stable position. Actuator 22 has contact surfaces 24 , 25 and 26 to interact with bistable mechanism 19 . As shown in FIG. 4 a , contact surface 25 has a flexible frame 33 and inside close-by hard surface 34 . When contact force is applied, the contact surface 25 will become self-contacting. This can decrease contact force on each surface therefore increase contact life time. FIG. 4 b shows the self-contacting off-center contact surface 26 design. Similarly, the flexible frame 35 will contact with the inside close-by hard surface 36 when contact force applied. Therefore, the contact force is decreased for each surface. Actuator 27 , which for switch the mirror 18 from its the second stable position to its first stable position, has contact surfaces self-contacting surface 29 , 30 and 31 similarly as shown in FIGS. 4 a and 4 b.
In one embodiment the method of these teachings includes providing an optical switch as described herein above where the bistable component and the reflective opponent are in initial state, the initial state being the first stable configuration or the second stable configuration, applying a predetermined voltage across the actuating component, the actuating component being either the first or the second electrothermal bent beam actuator depending on the initial state. The predetermined voltage causes a current equal to or higher than a predetermined current to flow across the actuating component. The current flow in the actuating component causes the actuating component and the driving component, the driving component being the first or second contacting component, to advance the bistable component of the reflective component from the initial state to a second state, the second state being the other stable configuration. By moving the reflective component from one stable configuration to the other stable configuration, one or more optical beams are switched.
The above disclosed embodiment of the method of these teachings can also include measuring a resistance change in the bistable component in order to determine whether the bistable component is in the first stable configuration or in the second stable configuration. In another instance, the embodiment of the method includes measuring a change in the capacitance between the first electrothermal bent beam actuator and the bistable component or between the second electrothermal bent beam actuator and the bistable component. The above embodiments of the method of these teachings are not limited to configurations in which the bistable component is in the first stable configuration or in the second stable configuration. Methods that apply to either configuration are within the scope of these teachings.
When the first contacting component has a first number of contact surfaces and the second contacting components has a second number of contact surfaces, applying a predetermined voltage across the actuating component (first or second electrothermal bent beam actuator) causes each one of the contact surfaces, in either the first number of contact surfaces or the second number of contact surfaces, at a different time in a time sequence (also referred to as at one predetermined time from a number of predetermined times).
FIGS. 2 a and 2 b illustrate the operation of the optical switch in one embodiment of an optical system, these teachings not being limited to only that optical system. Referring to FIGS. 2 a and 2 b , the embodiment 100 shown therein includes an optical switch 1 such as disclosed hereinabove, a first optical system 101 and a second optical system 102 and optical beams 108 , 109 propagating between optical system 101 an optical system 102 . Optical beams 104 and 105 input/exit the first optical system 101 and optical beams 106 and 107 exit/input the second optical system 102 . In the configuration shown in FIG. 2 a , the two optical beams 108 , 109 propagate unobstructed between the first optical system 101 and the second optical system 102 . When the optical switch is operated and the reflective component moves to the other stable configuration, as shown in FIG. 2 b , the reflective component intersects the propagating beams 108 , 109 . The propagating beams 108 , 109 can be deflected to a location different from the other optical system.
In one embodiment, the MEMS fabrication steps are simplified by using silicon on insulator (SOI) wafers. MEMS fabrication steps comprise only 5 steps: patterning the front and back sides, front-side deep reactive ion etching (DRIE), back-side DRIE, release of the buried oxide layer (box) oxide, and front-and-back metal depositions. This processing has the advantage that every step has a defined stop by the wafer structure; therefore the process control monitoring is drastically simplified. Specifically, the front-side DRIE will be stopped at the buried oxide layer, the back-side DRIE will also be stopped at the buried oxide layer, the oxide release will have minimal etch rate on the Si material, and metal deposition step (preferred a dry processing step) will have minimal impact to the released spring. The process flow is shown in FIGS. 5 a - 5 b . The process starts with FIG. 5 a the SOI wafer substrate, proceeding to FIG. 5 b device layer pattern, then FIG. 5 c BOX layer pattern to protect the device, then FIG. 5 d backside release etch and, lastly FIG. 5 e the remaining BOX is stripped away, resulting in a completed optical switch.
For the purposes of describing and defining the present teachings, it is noted that the term “substantially” is utilized herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. The term “substantially” is also utilized herein to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue.
Although the invention has been described with respect to various embodiments, it should be realized these teachings are also capable of a wide variety of further and other embodiments within the spirit and scope of the appended claims. | An optical switch including a bistable component, a reflective component, the reflective component being operatively connected to the bistable component, a first electrothermal bent beam actuator, a first contacting component operatively connected to the first electrothermal bent beam actuator component, the first electrothermal bent beam actuator component and the first contacting component disposed such as to enable advancing the bistable component the reflective component from a first stable configuration to a second stable configuration, a second electrothermal bent beam actuator component and a second contacting component operatively connected to the second electrothermal bent beam actuator component, the second electrothermal bent beam actuator component and the second contacting component disposed such as to enable advancing the bistable component and the reflective component from the second stable configuration to the first stable configuration. | 8 |
BACKGROUND OF THE INVENTION
[0001] 1. Technical Field
[0002] This invention relates generally to content caching, such as caching web pages in the context of web servers on the Internet. More particularly, the invention relates to such caching where multiple requests for the same content from the caching server to the content server(s) are specially handled.
[0003] 2. Description of the Prior Art
[0004] Web browsing on the Internet is perhaps one of the most popular applications of the Internet. Using a web browser program on a client, a user enters in the address of a web site or web page hosted by one or more web servers. The client contacts these web server(s) at this address on the Internet, which is known as a universal resource locator (URL) address. This address typically has the form “http://www.name.suffix/page.htrnl,” where the suffix may be “corn,” “org,” or another suffix. The web server receives the request, and returns content to the client identified by the address. Once the client receives the content, the web browser program interprets it to properly display the content to the user.
[0005] A difficulty that has become apparent when using web servers to host web sites is that a web server usually only has the capability of serving so many web pages at a time. For instance, a web server may have the ability to handle 1,000 web page requests per second. However, as the popularity of a web site increases, the web server may have to handle more than its original capability of web page requests. Typical solutions have centered around implementing scalable servers, which can be expanded as need warrants, as well as adding additional web servers, which can be clustered with the original server(s) so that proper load balancing is achieved.
[0006] A more recent solution that has seen increased usage is employing a caching server. A caching server is usually located in front of the web server, and may handle incoming web page requests directly from clients, passing on requests to the web server only when necessary. The caching server caches content according to a predetermined approach, such that the caching server can respond to client requests for content that has been cached without passing the requests along to the web server. This alleviates much of the burden placed on the web server, effectively allowing the web server to handle more client requests than if the caching server were not used.
[0007] Content typically can be classified as either cacheable or non-cacheable. Cacheable content is generally that which is not particular to a given user's request, and that does not require customization by the web server to properly respond to the user's request. For instance, a news-oriented web site may have content regarding a breaking news story. Regardless of the client that requests this content, the web site returns the same content. Therefore, this content is cacheable, in that the caching server is able to cache the content and return it to any requesting client.
[0008] By comparison, non-cacheable content is generally that which is particular to a given user's request, and thus requires customization by the web server to properly respond to the user's request. For instance, a banking web site may have content directed to each of its account holder's accounts. When a client requests account-related content from the site, the content is not applicable to any other client, since each client will request account-related content of its own user. Therefore, this content is non-cacheable, in that the caching server should not cache the content.
[0009] A problem with caching servers, however, occurs when multiple client requests for the same content are retrieved in a short time span, before the web server responsible for the content has responded to the first such request. For example, the caching server may receive a client request for cacheable content that has not yet been cached, and pass it along to the web server. Before the caching server receives the content from the web server to cache and return to the requesting client, the caching server receives one or more additional client requests for the same content. Because this content has not yet been cached, the caching server passes along these requests, too, to the web server.
[0010] The web server in this scenario is therefore burdened with having to respond to essentially the same request for content a number of times, in contradistinction to the purpose of having a caching server offload this burden from the web server. With each additional client request for the same content passed along to the web server before the web server responds to the original request for the content, the web server's ability to handle any request for content for which it is responsible decreases. That is, with each additional client request that it receives for the same content, there is a longer delay in the web server responding to the initial client request for this content.
[0011] This effect is known generally as the positive feedback, or snowball effect, in that the more client requests the web server receives, the worse its performance becomes. Existing caching servers assume that this situation will occur with sufficiently low frequency that it does not affect the ability of the web server to handle content requests. However, this assumption is at best dubious, and even if this scenario occurs infrequently, when it does, it can greatly degrade web server performance, to the detriment of the users and the operator of the web site. For these described reasons, as well as other reasons, there is a need for the present invention.
SUMMARY OF THE INVENTION
[0012] The invention relates to special handling of multiple identical requests for content during content caching. A method of the invention receives a request for content. The method performs at least one of two actions. First, in response to determining that the content is cacheable and that a previous request for the content has already been forwarded to a server responsible for the content, the method waits to process the request until it receives a response to the previous request. Second, in response to determining that the content is non-cacheable, the method forwards the request to the server responsible for the content.
[0013] A system of the invention includes first and second storages, and a mechanism. The first storage stores cacheable content by identifiers thereof, where the cacheable content is received from one or more content servers. The second storage tracks outstanding requests for content that have been sent to the content servers, by identifiers of the content. The mechanism receives a new request for content that includes an identifier. In response to determining that the second storage is tracking other request(s) also having the identifier of the new request, the mechanism adds the new request to these other request(s) in the second storage.
[0014] An article of manufacture of the invention includes a computer-readable medium and means in the medium. The means in the medium is for waiting to process a received request for content, until a response is received to another request for the content that has already been sent to a server responsible for the content. The means is also for forwarding the received request to the server after determining that the content is non-cacheable. Other features and advantages of the invention will become apparent from the following detailed description of the presently preferred embodiment of the invention, taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] [0015]FIG. 1 is a flowchart of a method according to a preferred embodiment of the invention, and is suggested for printing on the first page of the issued patent.
[0016] [0016]FIG. 2 is a diagram of a system in conjunction with which embodiments of the invention can be implemented.
[0017] [0017]FIG. 3 is a diagram of a caching server and associated components, according to an embodiment of the invention.
[0018] [0018]FIG. 4 is a flowchart of a method showing how one embodiment of the invention processes requests received for content.
[0019] [0019]FIG. 5 is a flowchart of a method showing how one embodiment of the invention processes responses received from content server(s).
DESCRIPTION OF THE PREFERRED EMBODIMENT
Overview
[0020] [0020]FIG. 1 shows a method 100 according to a preferred embodiment of the invention. Along with other methods of the invention, the method 100 may be performed by a caching server that receives client requests for content, and that passes at least some of these requests to one or more content servers, such as web servers. The method 100 further may be implemented by one or more means stored on a computer-readable medium of an article of manufacture. The medium may be a recordable data storage medium, a modulated carrier signal, or another type of medium.
[0021] A request for content is first received ( 102 ). The content may be a web page, a web object, or another type of content. The request may be received over the Internet, or over one or more other types of networks in addition to or in lieu of the Internet. Depending on the type of content that has been requested, one of four different actions can be performed. Such actions include those that correspond to cacheable content that has already been cached ( 104 ), as well as unclassified content that has not been cached but for which no other outstanding requests have been made ( 106 ). The actions also include those that correspond to unclassified content that has not been cached and for which other outstanding requests have been made ( 108 ), and non-cacheable content, or more specifically content that has been marked as non-cacheable ( 110 ). With respect to cacheable content that has already been cached ( 104 ), the cached content is returned in response to the received request ( 114 ). That is, because a local copy of the content that has been requested is available, the content is returned.
[0022] With respect to unclassified content that has not yet been cached, and for which there are no other outstanding requests for the content ( 106 ), this is content that has not been cached, and no previous requests for the same content are outstanding to the content server. The request for the content is forwarded to the content server ( 136 ), and the content, along with an indication as to whether the content is cacheable or non-cacheable, are received back from the content server ( 138 ). If this classification indicates that the content is not cacheable ( 140 ), then the content is marked as non-cacheable for future reference ( 142 ), and is returned in response to the received request ( 144 ). If this classification indicates that the content is cacheable ( 140 ), then the content is cached ( 146 ), and returned in response to the received request ( 144 ).
[0023] With respect to cacheable content that has not yet been cached, and for which there are outstanding requests for the content ( 108 ), this is content that has not been cached, but one or more previous requests for the same content have already been made, where the first request was earlier forwarded to the content server. Therefore, the most recently received request is not forwarded to the content server. Rather, the content is received from the content server in response to the first request for the same content, along with an indication as to whether the content is cacheable or non-cacheable ( 150 ). If the classification indicates the content is cacheable ( 152 ), the content is cached ( 162 ) and returned in response to all the pending requests for the content ( 164 ), including the most recently received request. If the classification indicates that the content is instead non-cacheable ( 152 ), the content is marked as non-cacheable ( 154 ), and is returned only in response to the first request ( 156 ). The other pending requests are forwarded to the content server ( 158 ). Finally, with respect to content that has been marked as non-cacheable ( 110 ), the request is forwarded to the content server ( 130 ). The content is received from the content server ( 132 ). The content is then returned in response to the request ( 134 ).
Technical Background
[0024] [0024]FIG. 2 shows an example system 200 in conjunction with which embodiments of the invention may be implemented. The system 200 includes a number of clients 202 a , 202 b , . . . , 202 n . These clients 202 are typically computers or computerized devices on which web browser programs are running, such that they can generate requests for content, and receive the content back for proper interpretation and display to their users. The requests may be requests for web pages or other content addressable by universal resource locator (URL) addresses, as commonly found on the Internet's world wide web. The URL addresses are more generally referred to as identifiers.
[0025] The system 200 includes the Internet 204 , to which the clients 202 and a caching server 206 are communicatively coupled. The Internet 204 is generally one type of network. Other types of networks that are amenable to the invention in addition to or in lieu of the Internet 204 include intranets, extranets, virtual private networks (VPNs), wide-area networks (WANs), and local-area networks (LANs). The caching server 206 is shown on the side of content servers 210 a , 210 b , . . . , 210 n of the system 200 . However, alternatively the caching server 206 may be located on the side of the clients 202 , between the clients 202 and the Internet 204 .
[0026] The caching server 206 generally initially handles content requests received from the clients 202 . If the content requests relate to content that the caching server 206 has previously cached in the cache 208 , then the caching server 206 returns the cached content to the requesting clients without involving the content servers 210 . However, if the content requests relate to content that the caching server 206 has not stored in the cache 208 , then the caching server 206 passes the requests to one or more of the content servers 210 . The caching server 206 may determine to which of the content servers 210 to pass the requests, or it may allow one or more of the content servers 210 themselves to determine which among them should handle the requests. The content servers 210 can more specifically be web servers.
[0027] In either case, the caching server 206 receives the content back from the servers 210 , and returns the content back to the client of the clients 202 that had made the request. Those of ordinary skill within the art can appreciate that the description of the system 200 is for summary purposes only, and that other aspects of such systems not disclosed herein are still amenable to the invention. For instance, the cached content stored in the cache 208 may have time-to-live (TTL) markers as well as other attributes. The content servers 210 may be load balanced, or be consistent with other such algorithms and approaches.
Caching Server
[0028] [0028]FIG. 3 shows a system 300 of the caching server 206 and its associated components in more detail, according to an embodiment of the invention. These components include the cache 208 , a cacheable outstanding request buffer 306 , and a non-cacheable identifier buffer 308 . Any or all of these components may be part of the caching server 206 itself. The server 206 may be a general-purpose computer programmed to perform functionality according to an embodiment of the invention, a hardware device specifically designed to perform such functionality, and so on. The server 206 is generally a mechanism that performs this functionality, or may include a mechanism, such as a particular piece of hardware or software, that performs this functionality.
[0029] As indicated by the lines 302 and 304 , the server 206 can communicate with the clients 202 and the content servers 210 , respectively. The cache 208 stores cacheable content received from the content servers 210 , such that the caching server 206 is able to use such locally stored copies of the content to return in response to requests for such content from the clients 202 . The cache 208 may be one or more hard disk drives, or other types of storage. The buffers 306 and 308 are also more generally referred to as storages.
[0030] The cacheable outstanding request buffer 306 tracks requests for content that have been passed by the caching server 206 to the content servers 210 , but for which responses have not yet been received from the content servers 210 . The buffer 306 may be a bit-wise buffer implemented in hardware, a software-implemented buffer, or another type of buffer. By checking the buffer 306 before forwarding a request for content to the content servers 210 , the caching server 206 is able to avoid sending duplicate requests for the same content to the servers 210 , such that overburdening the servers 210 can be avoided.
[0031] The buffer 306 preferably stores the outstanding requests for content for which one such request has already been forwarded to the content servers 210 using lists organized by identifiers, such as URL addresses at which the content is located. For instance, for an initial request forwarded to the content server 210 , the buffer 306 stores the identifier and begins a list associated with this identifier that has the initial request as its first entry. Subsequent requests for the same content received by the caching server 206 before the response to the initial request is received from the servers 210 are then added in order to this list. When the content is then received back from the servers 210 , the list of request(s) in the buffer 306 for this content is removed.
[0032] The non-cacheable identifier buffer 308 tracks content that is non-cacheable. The buffer 308 may also be a bit-wise buffer implemented in hardware, a software-implemented buffer, or another type of buffer. The buffer 308 preferably tracks such content by identifiers, such as URL addresses at which the content is located. By checking the buffer 308 , the caching server 206 is able to determine whether the content requested by a client is non-cacheable.
[0033] Thus, if the content is non-cacheable, the caching server 206 immediately forwards the request to the content servers 210 . This occurs even though another, previously made request having the same identifier may have been forwarded to and to which the content servers 210 have not responded. This is because the content that the servers 210 ultimately return in response to such requests for non-cacheable content may, for instance, be customized for the individual clients making such requests, such that the content returned to the clients is not identical.
Handling of Requests for Content
[0034] [0034]FIG. 4 shows a method 400 according to which one embodiment of the invention handles requests for content received from clients. The method 400 is consistent with the method 100 of the preferred embodiment of the invention. First, a request for content is received ( 402 ) that includes an identifier, such as the URL address at which the content is located. If the requested content is in the cache ( 404 ), then the cached content is returned to the requesting client ( 406 ). If the requested content is not in the cache ( 404 ), however, then the method 400 determines if the identifier is in the non-cacheable buffer ( 408 ).
[0035] If so, then the request is forwarded to one or more of the content servers ( 416 ). Otherwise, the method 400 determines whether the identifier is in the cacheable outstanding request buffer ( 410 ). If the identifier is in this buffer, then the currently received request is added to the list of identical requests stored in the buffer ( 414 ), and the method 400 ends. However, if the identifier is not in this buffer, then the request is added to the buffer as the first entry of a new list in the buffer associated with the identifier ( 412 ). The request is then forwarded to one or more of the content servers ( 416 ).
Handling of Responses
[0036] [0036]FIG. 5 is a flowchart of a method 500 according to which one embodiment of the invention handles responses received from content servers in response to previously forwarded content requests. The method 500 is consistent with the method 100 of the preferred embodiment of the invention. First, a response from a content server is received ( 502 ) that includes content, an identifier for the content, and an indication as to whether the content is cacheable or non-cacheable.
[0037] If the content is indicated as cacheable ( 504 ), then the method 500 caches the content ( 506 ), and determines whether the identifier is in the cacheable outstanding request buffer ( 508 ). If not, then the content is returned in response to the request for the content ( 510 ). If so, however, then the content is returned in response to all the requests for the content in this buffer ( 512 ), and the identifier and its associated list of requests are removed from the buffer ( 514 ).
[0038] However, if the content is indicated as non-cacheable ( 504 ), then the method 500 determines whether the identifier is in the non-cacheable buffer ( 516 ). If it is, then the identifier is initially removed from the buffer ( 518 ), and re-added to the buffer at the beginning of the buffer ( 520 ). The identifier is also added to the beginning of the buffer where the identifier was not found in the non-cacheable buffer ( 520 ). Next, the method 500 determines whether the identifier is in the cacheable outstanding request buffer ( 522 ). If not, then the content is returned in response to the request for the content ( 524 ).
[0039] Otherwise, the identifier and its associated list of requests are removed from this buffer ( 526 ), and the content is returned in response to the initial request for this content that was originally forwarded to the content servers ( 528 ). All other requests for this content that were in the list stored in the buffer associated with the identifier are then forwarded to the content server(s) ( 530 ). Because the content is non-cacheable, the same content that was returned in response to the initial request for the content that had been forwarded to the content server(s) cannot be returned in response to the other requests.
Advantages over the Prior Art
[0040] Embodiments of the invention allow for advantages over the prior art. When a caching server according to an embodiment of the invention receives a request for cacheable content that has not yet been cached, but for which an earlier request has already been forwarded to a content server, the caching server does not also forward the current request to the content server. Rather, the caching server waits to process the current request until a response to the earlier request has been received, and then returns the content received from the content server in response to both such requests. In this way, the caching server avoids overburdening the content server with duplicate requests for the same cacheable content. The caching server thus prevents the positive feedback effect that may otherwise occur when the content server receives such duplicate requests.
[0041] Furthermore, when a caching server according to an embodiment of the invention receives a request for non-cacheable content, it automatically forwards the request to the content server. This ensures that embodiments of the invention can be used in situations where both non-cacheable and cacheable content are being served by a content server. Requests for non-cacheable content, such as dynamic content, are not blocked by the caching server, even if previous, identical requests for such content have already been forwarded to the content server. In this way, responsiveness to requests for non-cacheable content is not degraded.
Alternative Embodiments
[0042] It will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without departing from the spirit and scope of the invention. For instance, whereas the invention has been substantially described in relation to caching servers operating in conjunction with content servers that are web servers, and for content that includes web pages, the invention itself is not so limited. The invention is also applicable, for example, to other types of content servers, and other types of content besides web pages, and in other environments besides Internet-oriented environments.
[0043] As another example, buffers besides those described herein may be used in conjunction with the invention. For instance, there may only be a single buffer that tracks outstanding requests made to the content servers. The purpose of the non-cacheable buffer that has been described can in such instance be instead satisfied by the cache, where if content is not in the cache, it is initially presumed to be non-cacheable. Accordingly, the scope of protection of this invention is limited only by the following claims and their equivalents. | The special handling of multiple identical requests for the content during content caching is disclosed. A first for content, such as a web page request received from a client, is received. At least one of two actions is then performed. First, in response to determining that the content is cacheable and that a previous request for the content has already been forwarded to a server responsible for the content, such as a web server, the request is not processed until a response to the previous request is received. Second, in response to determining that the content is non-cacheable, the request is forwarded to the server responsible for the content. | 6 |
TECHNICAL FIELD
The invention relates in general to manufacturing electronic components and specifically relates to the manufacture of transducer arrays for a variety of systems.
BACKGROUND OF THE INVENTION
FIG. 1 is an illustration of example ultrasound transducer 100 . Transducer 100 includes, among other things, cable 101 that carries signals between transducer 100 and a processing and control unit (not shown). Transducer 100 also includes body 102 for providing a handle shape for an ultrasound operator to grip transducer 100 when performing an ultrasound examination. Surface 103 of transducer 100 contacts a patient or other subject and includes a plurality of individual transducer elements that transmit and receive acoustic waves during an examination. The processing and control unit controls the beam forming in transducer 100 and also processes the electrical signals produced by the transducer elements as the elements receive reflected acoustic waves during an examination.
FIG. 2 is an exploded view of example components 200 inside transducer 100 . As shown, cable 101 is connected to flex circuit 202 , and flex circuit 202 is connected to transducer array 201 such that the control and processing unit (not shown) is in electrical communication with transducer array 201 . Transducer array 201 includes individual acoustic transducer elements 204 , which, in this example, are individually controlled active acoustic elements that produce acoustic waves from electrical stimulation and produce electrical signals in response to receiving reflected acoustic waves. Transducer array 201 is usually fabricated as an “acoustic stack”—one or more ceramic or polymer layers that are metallized on both sides. As explained more fully below, the acoustic stack is cut into a plurality of individual transducer elements. The ceramic or polymer itself is not electrically conductive, but is a piezoelectric material that may be excited by applying a high voltage across its two outer surfaces. The control and processing unit detects minute voltage fluctuations in the signal received from array 201 and performs digital signal processing to produce an image for a human user.
Flex circuit 202 is an intermediary device to connect relatively rigid cable assembly 101 to fragile, small, and minute acoustic elements 204 . Flex circuit 202 , in this example, is a flexible printed circuit that includes a plurality of signal traces 203 and is similar in some respects to a ribbon. In some examples, flex circuit 202 includes signal traces on a layer of KAPTON™, which is a non-conducting, flexible polymer available from E.I. du Pont de Nemours and Company, that provides flexible support to the traces.
The current art provides for several ways to create an electrical connection between the system electronic circuits in the control and processing unit and the plurality of acoustic elements. Specifically, the prior art provides methods of electrically attaching cable assemblies from the control and processing unit to the acoustic stack itself. One example process includes embedding flex circuit 202 in a block of backing material (not shown), which helps to support both the acoustic stack and the flex circuit 202 during manufacturing and use and also helps to dampen acoustic vibrations in the assembly. A leading edge of flex circuit 202 is visible and exposed at a surface of the backing material so that an electrical connection can be made between flex circuit 202 and the acoustic stack by placing the acoustic stack on the surface so that it contacts flex circuit 202 . No soldering is used. The dicing saw operator then cuts through the acoustic stack and the backing material between each of signal traces 203 to create electrically isolated acoustic elements 204 . An example method for attaching a backing block and conductive elements to an acoustic stack without soldering is described in U.S. Pat. No. 6,104,126, issued Aug. 15, 2000, the disclosure of which is hereby incorporated herein by reference.
In contrast, current industry standards include soldering flex circuit 202 to the exposed metallized face or edges of the acoustic stack before dicing. A difficulty with both methods is that the exposed leading edge of flex circuit 202 is underneath the acoustic stack, thereby obscuring the signal traces and making the dicing operation more challenging.
FIG. 3 is an illustration of example flex circuit assembly 300 . Flex circuit 202 ( FIG. 2 ) includes KAPTON™ layer 303 and a plurality of signal traces 203 . Assembly 300 includes backing block 301 , which is made of a more rigid, nonconductive material (e.g. acoustic backing material) that surrounds flex circuit 202 . Assembly 300 includes surface 304 where a leading edge of flex circuit 202 is visible. In order to guide the dicing saw operator, the assembly line (or the saw operator) scribes backing block 301 with marks 302 (i.e., kerfs) to the edges of block 301 . Marks 302 are produced by making shallow cuts in block 301 between the signal traces, thereby transferring a datum feature to the outside of block 301 . Marks 302 may then be seen by the saw operator after the acoustic stack is laid down on block 301 . Marks 302 indicate spaces between the signal traces where cuts should be made. Marks 302 may be made for each signal trace or may be spaced apart by multiple signal traces in a pattern. In the example of FIG. 3 , marks 302 are spaced at every third signal trace.
In both examples above, the dicing cuts and the kerfs are based on the positions of the actual signal traces in the leading edge of flex circuit 202 . However, in some applications, discrete signal traces at the leading edges may not be available, making the above-described methods unusable.
BRIEF SUMMARY OF THE INVENTION
Various embodiments of the present invention are directed to systems and methods which include alignment markers in the flex circuit that are separate from the signal-carrying conductors. From the markers, scoring marks can be made on the backing block to guide a dicing saw. Alternatively, a dicing saw operator can guide the saw based on the markers, themselves. Example manufacturing techniques connect the signal traces in a buss at the leading edge of the flex circuit, thereby visually obscuring the individual signal traces at the leading edge. Accordingly, various embodiments of the invention may add utility to such techniques by providing alignment markers that are different and/or electrically isolated from the buss and the signal traces.
In one example embodiment, the flex circuit is made of a number of layers with the alignment markers on a layer different than the layer that includes the signal carrying traces. For instance, the markers may be included on a layer that is used for a ground plane and insulated from the signal carrying conductors by a flexible insulating layer. The markers indicate the positions of the signal traces and are exposed and/or visible at the leading edge of the flex cable. The alignment markers may be used to make kerfs or dices. In another example embodiment, the flex circuit includes a strip of material that protrudes out from the backing block and includes alignment markers. When the acoustic stack is placed on the backing block, the strip is folded down, and portions of the strip extend past the edge of the stack, thereby providing a visual indicator for the dicing saw operator to make cuts.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
FIG. 1 is an illustration of an example ultrasound transducer;
FIG. 2 is an exploded view of example components inside an example transducer;
FIG. 3 is an illustration of an example flex circuit assembly;
FIG. 4 is an illustration of an example flex circuit assembly according to one embodiment of the invention;
FIG. 5 is an illustration of an example flex circuit assembly according to one embodiment of the invention;
FIG. 6 is a flowchart of an example method for manufacturing a transducer device with the flex circuit assembly of FIG. 4 ; and
FIG. 7 is a flowchart of an example method for manufacturing a transducer device with the flex circuit assembly of FIG. 5 .
DETAILED DESCRIPTION OF THE INVENTION
FIG. 4 is an illustration of example flex circuit assembly 400 according to one embodiment of the invention. Assembly 400 includes backing block 406 , and embedded signal traces 402 are present inside backing block 406 but cannot be seen by a human operator. Flex circuit 407 includes buss 404 , which terminates and shorts signal traces 402 at the leading edge thereof, so that a human operator sees a line of copper or other conducting material when viewing surface 405 . When the operator dices the acoustic stack (not shown), the cuts extend past the depth of buss 404 , thereby creating individual contacts out of a once continuous strip of conducting material. Buss 404 , once it is diced, provides wide contacts between the transducer elements and their respective signal traces 402 . An advantage of using buss 404 rather than individual signal traces at the leading edge of flex circuit 407 is that the buss provides wider contacts, and the reliability and signal conducting quality of a contact usually increases with its width.
The flex circuit also includes flexible insulating layer 408 , possibly made of KAPTON™, that provides some support to traces 402 . Despite its name, however, flex circuit 407 is not required to be flexible, as insulating layer 408 may be constructed of fiberglass or other more relatively rigid material.
When dicing or scribing marking lines on surface 405 , an operator cannot rely on visual inspection of traces 402 to determine their positions because signal traces 402 are not visible at the leading edge. Therefore, the prior art methods described above provide little utility in this example. Accordingly, flex circuit 407 includes markers 401 that indicate positions of signal traces 402 . Alignment markers 401 may be aligned with signal traces 402 or may be aligned with spaces between signal traces 402 , in which case, markers 401 would implicitly (rather than explicitly) indicate the positions of traces 402 . The invention is not limited to any particular method of alignment as long as a person or machine may determine or infer placement of traces 402 from markers 401 .
Markers 401 may be produced, for example, by laying down an additional layer of conducting material on flex circuit 407 . Typical flex circuits include several alternating layers of insulating material (e.g., KAPTON™) and conducting material (e.g., copper). The conducting material carries the electrical signals and the insulating material isolates the signal-carrying traces from each other. Alignment marks 401 can be an additional layer of copper bonded to the surface of insulating layer 408 , or can be part of an existing layer of material in flex circuit 407 . For example, alignment marks 401 can be applied to flex circuit 407 along with a copper ground plane, assuming that marks 401 are electrically isolated from the rest of the copper in the plane. For instance, the ground plane may stop short of the alignment markers and the end of the flex circuit to avoid shorting the transducers. Such a feature may provide for less expensive manufacturing of assembly 400 , since the alignment markers may be printed with the ground plane. Signal traces 402 , in this example, are of a pitch equal to that of alignment markers 401 ; however, the pitch of markers 401 may be a multiple or other ratio of the pitch of traces 402 .
A possible way to dice the acoustic stack and create individual transducer elements is to fabricate buss 404 to a very precise length, and then index a computerized saw blade from one end of buss 404 . The program controlling the saw then makes precise cuts at predetermined distances from the end. However, a disadvantage is that some amount of inaccuracy is typically present, especially when using only one end of buss 404 as an index.
A second possible way to dice the acoustic stack is to create kerfs 403 on surface 405 to guide the saw operator. Since alignment markers 401 are visible on surface 405 and are precisely placed to indicate the positions of traces 402 , a human or machine can make kerfs 403 aligned with markers 401 to indicate placement of dicing cuts. The acoustic stack may then be placed on surface 405 and diced according to kerfs 403 . In this way, a saw operator is ensured that such cuts will be placed between traces 402 , thereby creating a plurality of individual transducer elements.
In one example, kerfs 403 are only about two thousandths of an inch deep so that they make a mark in block 406 but do not sever buss 404 . During the final dice, the operator cuts through the acoustic stack and into backing block 406 , which, in this example, is enough to sever buss 404 , which is typically a few thousandths of an inch in depth.
FIG. 5 is an illustration of example flex circuit assembly 500 according to one embodiment of the invention. FIG. 5 is a side view of assembly 500 , positioned such that buss 404 and signal traces 402 appear to the eye as a single, vertical component. Assembly 500 includes backing block 406 , buss 404 , traces 402 , and non-conducting layer 408 . In this example, the alignment markers are included on flap 501 . For instance, flap 501 includes alignment markers as vertical lines (not shown) that indicate the placement of signal traces 402 . Flap 501 protrudes from block 406 and can be bent outward and away from acoustic stack 502 during placement of acoustic stack 502 . This provides the dicing saw operator with one or more marks that are beyond the periphery of acoustic stack 502 and, therefore, visible at the time of dicing. The saw operator can then dice acoustic stack 502 according to the markers. It is possible that flap 501 may be trimmed off and removed after dicing, and may not be used for other processes in the assembly of the transducer.
Flap 501 may be made of a nonconductive material, such as KAPTON™, or may be made of copper or other materials as long as it does not interfere with the signal connections of the transducer array. In fact, flap 501 may be part of an existing KAPTON™ layer that is extended beyond block 406 . Alternatively, flap 501 may include thin pieces of copper extending beyond the KAPTON™, whereby the pieces of copper, themselves, act as the alignment markers. An advantage of some embodiments that use flaps is that the flaps take the place of scoring, thereby eliminating the step of making kerfs.
FIG. 6 is a flowchart of example method 600 for manufacturing a transducer device with flex circuit assembly 400 ( FIG. 4 ). In step 601 , a person or machine provides a cable with a flex circuit and a supporting block. The flex circuit includes a plurality of conductors terminating at a leading edge of the cable, and the plurality of conductors are placed upon a layer of insulating material, and a plurality of alignment markers are also placed upon the layer of insulating material at the leading edge. The plurality of alignment markers are electrically isolated from the plurality of conductors, and are, therefore, separate from the conductors.
The cable also includes a supporting block surrounding the flex circuit and exposing the leading edge of the flex circuit at a surface of the supporting block. Further, the plurality of alignment markers at the leading edge indicate positions of the plurality of conductors. Flex circuit assembly 401 of FIG. 4 is suitable for use as the cable in step 601 . In such an embodiment, the plurality of conductors includes signal traces connected by a buss at the leading edge of the cable.
In step 602 , a person or machine scores the surface of the supporting block based on the alignment markers to produce kerfs that indicate the positions of the plurality of conductors. In one example, the kerfs are aligned with edges of the markers. In another example, the kerfs are aligned with the midpoints of the markers. The invention is not limited to any particular way of aligning kerfs with alignment markers, and any given way is within the scope of one or more embodiments. The kerfs extend toward the edge of the block sufficient to be visible after the acoustic stack is placed on the block.
In step 603 , a person or machine positions an electronic component on the surface of the supporting block so that the electronic component is in electrical communication with the plurality of conductors. In an example embodiment, an acoustic stack is placed on the surface so that it contacts the buss that connects the signal traces. In an embodiment that terminates signal traces without a buss, step 603 includes positioning the electronic device so that electrical connection is made with an adequate number of individual traces.
In step 604 , a person or machine dices the electronic component at one or more places, based upon the kerfs, to produce a plurality of separate transducer elements. In an embodiment wherein the kerfs are aligned with spaces between the conductors, dicing cuts may be made directly on the kerfs. In embodiments wherein the kerfs are aligned with the conductors, dicing cuts may be made between the kerfs, for example, at particular offsets from each kerf. When the flex circuit connects signal traces with a buss at the leading edge, step 604 may further include cutting through the buss to make electrically separate transducer elements.
FIG. 7 is a flowchart of example method 700 for manufacturing a transducer device with flex circuit assembly 500 ( FIG. 5 ). In step 701 , a person or machine provides a cable that includes a flex circuit. The flex circuit has a plurality of conductors terminating at a leading edge of the cable, and the plurality of conductors are placed on a layer of an insulating material.
The cable also includes a supporting block surrounding the flex circuit and exposing the leading edge at a surface of the supporting block. Further, the leading edge includes a structure that extends beyond the surface of the supporting block and has visual markings that indicate positions of the plurality of signal traces. Flex circuit assembly 500 ( FIG. 5 ) may be used as the cable of step 601 .
In step 702 , a person or machine positions an electronic component on the surface of the supporting block so that the structure is folded and the markings extend beyond the edges of the electronic component. In an example, an acoustic stack is placed on the supporting block, and the structure is a flap of KAPTON™ with alignment marks that is folded over.
In step 703 , based upon the markings, a person or machine dices the electronic component to produce a plurality of separate transducer elements, and each element is connected to at least one conductor of the plurality of conductors. In an example, a dicing saw operator aligns the saw with the markings on the part of the structure that extends beyond the acoustic stack. Then, the operator dices the stack as many times as necessary to produce a desired number of elements.
In step 704 , a person or machine removes a portion of the structure that extends beyond the edges of the electronic component. In an example embodiment, the flap of material with markings is not used for other purposes, and is removed by trimming in preparation for creation of a consumer or professional-grade finished product.
An advantage of some embodiments of the invention is that the shape of the alignment markers can be unique to the transducer, since the markers are not a part of the signal carrying circuitry. Therefore, a manufacturer typically will not have to take into account the effects of the markers on the signal-carrying properties of the transducer assembly. In fact, a manufacturer can design the markers any desirable way, keeping in mind the shape of the transducer, as the shape of the markers is not dependent on another function. Thus, some embodiments of the present invention allow for the separation of functions of markers and elements that affect performance, thereby permitting engineers to optimize each separately.
It should be noted that some manufacturers use computer programs to space out the dicing cuts of the acoustic elements in relation to features that have little relation to the acoustic performance of the product, for example, by using the edges of the backing block to index cuts. Various embodiments of the present invention may provide for more accuracy, since the markers are laid out in an alignment related to that of the traces.
Additionally, some embodiments are not limited to simply making cuts aligned between leads. For example, in some embodiments it might be desirable to place the leads off center while still making cuts along the entire length of the acoustic stack. Accordingly, alignment markers may be placed where necessary to guide the dicing saw operator. Therefore, in a general sense, some embodiments allow placing markers in any desirable pattern or placement.
Further, a manufacturer may use optical or electrical sensing machinery to recognize the markers and to place the kerfs and/or dicing cuts. For instance, machines may be able to detect the placement of markers made of conducting material (as in FIG. 4 ) by deriving an electromagnetic signal from the markers. The markers may also be used to conduct signals if desired. For example, a machine may detect the markers when receiving the signal through contact. These features may permit the development of specialized machinery to recognize and follow alignment marks.
Various embodiments of the invention may improve the accuracy of dicing cuts above that provided by prior art dicing techniques. For example, basing dicing cuts on kerfs, such as those described with regard to FIG. 4 , may result in fewer cut signal traces than the prior art technique of indexing from a side of the acoustic stack. Fewer cut traces leads to less waste and less cost to the manufacturer.
The examples above describe transducer arrays with a single row of elements. However, those of skill in the art will recognize that some embodiments may be adapted for use in systems that have multiple rows of elements. Further, the array may be straight or curved (concave or convex), depending on the application.
While the examples herein describe embodiments in the context of flex circuits in acoustic transducers, the invention is not so limited, as some embodiments may be adapted for use in systems that include optical, pressure, or other transducers. In fact, some embodiments may be adapted for use, more generally, in any kind of application that includes a plurality of small contacts on diced electrical components. For instance, a manufacturer may lay down a pattern of fine-conductor coaxial cables to make contact with a side of a transducer array. Then the manufacturer may make connections by, for example, soldering the cables to the transducer before it is diced. According to one embodiment of the invention, instead of relying upon the soldered connections, themselves, as guides for cutting, the manufacturer may add a secondary layer of alignment features that are not part of the signal-carrying circuit to indicate positions of the conductors. Examples of possible alignment features include lines on a sheet of insulating material and copper tabs that are laid down and insulated from a ground plane.
Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps. | A method and system include a cable including a plurality of conductors terminating at a leading edge of the cable, and markers disposed at the leading edge providing visual reference points at one or more predetermined positions, the markers being separate from the plurality of conductors. | 7 |
BACKGROUND OF THE INVENTION
This invention relates to flame-retardant polyphenylene ether resin compositions. More particularly, this invention relates to a flame-retardant composition (I) produced by adding a styrene type polymer to a polyphenylene ether and mixing the resultant resin composition with a phosphorus-containing compound; a flame-retardant composition, (II) produced by adding a styrene type polymer to a polyphenylene ether having a styrene type compound graft-copolymerized thereto and mixing the resultant resin composition with a novel organic phosphorus-containing compound; and a flame-retardant composition (III) produced by mixing said flame-retardant composition with at least one compound selected from the group consisting of (a) aromatic organophosphorous acid esters and (b) aromatic organophosphorous acid esters and triazole ring-containing compounds.
In recent years, polyphenylene ether resins have come to have great attention because they have excellent mechanical properties, electrical properties, chemical resistance and thermal resistance, exhibit low hydroscopicity and enjoy high dimensional stability. Further, since polyphenylene ethers possess excellent flame retarding properties, they are rated as self-extinguishing and non-dripping by ASTM Testing Method D-635 and specification No. 94 of Underwriters' Laboratories (hereinafter abbreviated as "UL-94"). Polyphenylene ethers, however, have long had poor fabricability, which constitutes their gravest defect. As means for improvement in this respect, there have been suggested a number of methods resorting to the addition of styrene type polymers. For example, Japanese Patent Publication No. 17812/1968, Japanese Patent Publication No. 32774/1973, U.S. Pat. No. 3,383,435, etc., disclose compositions containing polyphenylene ethers blended with styrene type polymers. There have also been suggested a number of methods restorting to graft polymerization of styrene type compounds. For example, Japanese Patent Publication No. 1210/1972, U.S. Pat. No. 3,664,977, Japanese Laid-open Patent Publication No. 98446/1974, U.S. Pat. No. 3,929,931, U.S. Pat. No. 3,586,736, U.S. Pat. No. 3,664,977 and U.S. Pat. No. 3,929,931 disclose resin compositions having styrene type compounds graft copolymerized to polyphenylene ethers.
The resin compositions having the fabricability of polyphenylene ethers improved as disclosed by these prior patent publications, however, have the disadvantage that they do not make materials suitable in regard to flammability for a wide range of industrial uses because the styrene type polymers incorporated therein possess neither self-extinguishing properties nor non-dripping properties and, upon ignition, they are completely burnt out.
SUMMARY OF THE INVENTION
An object of the present invention is to provide polyphenylene ether resin compositions having both improved fabricability and flame-retardancy.
To be specific, this invention provides a flame-retardant composition (I) which substantially comprises (A) 85 to 97% by weight of a resin component consisting of (1) 20 to 90% by weight of a polyphenylene of the generic formula (A): ##STR3## where R 1 and R 2 are each an alkyl of 1 to 4 carbon atoms and m is the degree of polymerization, and (2) 10 to 80% by weight, based on the resin component, of a styrene type polymer and (B) 3 to 15% by weight, based on the whole composition, of at least one compound selected from the group consisting of phosphorus-containing compounds of the generic formula (B): ##STR4## where X is a hydrogen atom, a hydroxyl, an amino, a halogen, an alkyl of 1 to 10 carbon atoms, an alkoxy of 1 to 10 carbon atoms, an alkylthio of 1 to 10 carbon atoms, an aryloxy of 6 to 10 carbon atoms or a hydroxyl-substituted aryloxy of 6 to 10 carbon atoms, Y 1 and Y 2 are each an alkyl of 1 to 8 carbon atoms or of 1 to 8 carbon atoms, or an aryl group, Z is an oxygen or sulfur atom, n and p are each an integer of from 0 to 4 and q is an integer of 0 or 1.
The present invention further relates to a flame-retardant composition (II) which substantially comprises 80 to 98% by weight of a resin component and 2 to 20% by weight of at least one compound selected from the group consisting of phosphorus-containing compounds of the generic formula (B): ##STR5## where X is a hydrogen atom, a hydroxyl, an amino, a halogen, an alkyl of 1 to 10 carbon atoms, an alkoxy of 1 to 10 carbon atoms, an alkylthio of 1 to 10 carbon atoms, an aryloxy of 6 to 10 carbon atoms or a hydroxyl-substituted aryloxy of 6 to 10 carbon atoms, Y 1 and Y 2 are each an alkyl of 1 to 8 carbon atoms, an alkoxyl of 1 to 8 carbon atoms or an aryl group, Z is an oxygen or sulfur atom, n and p are each an integer of from 0 to 4 and q is an integer of 0 or 1, said resin component comprising a styrene type compound grafted polyphenylene ether copolymer and a styrene type polymer and containing 20 to 80% by weight, based on the resin component, of a polyphenylene ether of the generic formula (A): ##STR6## where R 1 and R 2 are each an alkyl of 1 to 4 carbon atoms and m is the degree of polymerization, said styrene type compound grafted polyphenylene ether copolymer having 20 to 200 parts by weight of a styrene type compound grafted onto 100 parts by weight of said polyphenylene ether. Furthermore, this invention provides a flame-retardant composition (III) which substantially comprises 80 to 98% by weight of a resin component, 1 to 18% by weight of at least one compound selected from the group consisting of phosphorus-containing compounds of the generic formula (B): ##STR7## where X is a hydrogen atom, a hydroxyl, an amino, a halogen, an alkyl of 1 to 10 carbon atoms, an alkoxy of 1 to 10 carbon atoms, an alkylthio of 1 to 10 carbon atoms, an aryloxy of 6 to 10 carbon atoms or a hydroxyl-substituted aryloxy of 6 to 10 carbon atoms, Y 1 and Y 2 are each an alkyl of 1 to 8 carbon atoms, an alkoxy of 1 to 8 carbon atoms or an aryl group, Z is an oxygen or sulfur atom, n and p are each an integer of from 0 to 4 and q is an integer of 0 or 1, and 1 to 18% by weight each of at least one compound selected from the group consisting of aromatic organophosphoric acid esters, aromatic organophosphorous acid esters and triazine ring-containing compounds of the generic formula (C): ##STR8## melamine or benzoquanamine where X 1 is a phenyl or ##STR9## X 2 and X 3 are each a hydrogen atom or CH 2 OX 5 , X 4 and X 5 are each a hydrogen atom, CH 3 , C 2 H 5 , C 3 H 7 or C 4 H 9 , said resin component comprising a styrene type compound grafted polyphenylene ether copolymer and a styrene type polymer and containing 20 to 80% by weight, based on the resin component, of a polyphenylene ether of the generic formula (A): ##STR10## where R 1 and R 2 are each an alkyl of 1 to 4 carbon atoms and m is the degree of polymerization, said styrene type compound grafted polyphenylene ether compolymer having 20 to 200 parts by weight of a styrene type compound grafted onto 100 parts by weight of said polyphenylene ether.
Examples of the polyphenylene ethers to be used in flame-retardant compositions (I), (II) and (III) include poly(2,6-dimethylphenylene-1,4-ether), poly(2,6-diethylphenylene-1,4-ether), poly(2-methyl-6-ethylphenylene-1,4-ether), poly(2-methyl-6-propylphenylene-1,4-ether), poly(2,6-dipropylphenylene-1,4-ether), poly(2-ethyl-6-propylphenylene-1,4-ether), poly(2-methyl-6-butylphenylene-1,4-ether), poly(2,6-dibutylphenylene-1,4-ether) and poly(2-ethyl-6-butylphenylene-1,4-ether). The most advantageous polyphenylene ether for the purpose of the present invention is poly(2,6-dimethylphenylene-1,4-ether). This particular polymer excels in compatibility with styrene type polymers, permits resin compositions of varying proportions to be readily prepared and manifests an outstanding effect in imparting flame-retardancy due to its sunergism with the organic phosphorus compounds.
For the flame-retardant composition (I) of this invention to be effectively practiced, the number-average molecular weight of the polyphenylene ether is in the range of 6,000 to 30,000, preferably 7,000 to 25,000. Use of a polyphenylene ether having a number-average molecular weight of less than 6,000 is undesirable because of the polymer notably degrades the resultant resin composition in physical properties, particularly creep properties. Use of a polyphenylene ether having a higher molecular weight exceeding 30,000 is likewise undesirable because the polymer seriously degrades the resin composition in fabricability, causes degradation of the styrene type polymer and inhibits maintenance of balanced physical properties.
The term "styrene type compound" as used with respect to the flame-retardant composition (I) of this invention is meant to embrace polymers preponderantly comprising styrene type compounds whose number-average molecular weights fall in the range of from 50,000 to 200,000, preferably from 60,000 to 150,000. Concrete examples of styrene type compounds include styrene, α-methyl styrene, 2,4-dimethyl styrene, monochloro-styrene, dichloro-styrene, 2,4-dimethyl styrene, monochloro-styrene, dichloro-styrene, p-methyl styrene, p-tert.-butyl styrene and ethyl styrene and the like, e.g. lower alkyl styrenes and halostyrenes. At the time of polymerization, these styrene type compounds may be used in combination with copolymerizable vinyl compounds such as, for example, methyl methacrylate, acrylonitrile, methacrylonitrile, butyl acrylate and butadiene. The styrene type polymers, further, embrace generally known rubber-reinforced resins. For example, rubber-reinforced polystyrene resins, e.g., natural rubber or butadiene-acrylonitrile rubber reinforced polystyrene and acrylonitrile-butadiene-styrene copolymer resins are embraced therein. The proportion of the styrene type polymer to the whole resin component is in the range of from 10 to 80% by weight, preferably from 15 to 75% by weight. If the content of the styrene type polymer is less than the lower limit 10% by weight, the styrene type polymer fails to impart ample fabricability to the resultant resin composition. If the content exceeds the upper limit 80% by weight, the styrene type polymer may be unable, depending on the condition of mixture thereof with the phosphorus-containing compound of this invention, to confer desired flame-retardancy upon the resultant composition. If the number-average molecular weight of the styrene type polymer is below 50,000, there is the disadvantage that the physical properties of the resultant resin, particularly impact strength and creep properties, are deficient. If it exceeds 200,000, however, there ensues an adverse effect upon the moldability and fabricability, which results in various undesirable phenomena such as thermal deterioration of the composition at the time of fabrication and inferior impact resistance of the shaped article due to residual strain.
The expression "graft copolymer having a styrene type compound grafted onto a polyphenylene ether" as used in connection with the flame-retardant compositions (II) and (III) of this invention is meant to embrace those having 20 to 200 parts by weight of styrene type compound polymer graft polymerized onto 100 parts by weight of a polyphenylene ether of the generic formula (A): ##STR11## where R 1 and R 2 are each an alkyl of 1 to 4 carbon atoms and m is the degree of polymerization.
The preparation of this graft copolymer is accomplished as by a method touched upon in U.S. Pat. No. 3,929,930, for example.
The number-average degree of polymerization of the polyphenylene ether to be used in the preparation of the graft copolymer as one component of the flame-retardant composition (II) of the present invention is selected in the range of from 50 to 300, preferably from 70 to 250. If the number-average degree of polymerization of the polyphenylene ether is less than the lower limit of 50, the object of this invention cannot be attained because the graft copolymer cannot easily be obtained in a form perfectly free from residual homopolymer of the polyphenylene ether and the resin composition obtained as the final product exhibits undesirable properties. If there is used a polyphenylene ether in which the number-average degree of polymerization exceeds the upper limit of 300, an undesirable effect is manifested on the fluidity of the finally produced resin composition. In the extreme case, the resin composition is deprived of its fluidity to the extent of undergoing gelation.
In the polyphenylene ether having a styrene type compound graft polymerized thereto and used in the flame-retardant compositions (II) and (III) of the present invention, the term "styrene type compound" is meant to embrace styrene and styrene derivatives such as alkylated and halogenated styrene. Concrete examples of said styrene type compounds include styrene, α-methyl styrene, 2,4-dimethyl styrene, monochloro-styrene, dichloro-styrene, p-t-butyl styrene, p-methyl styrene, ethyl styrene and the like.
At the time of polymerization, these styrene type compounds may be used in combination with copolymerizable vinyl compounds such as, for example, methyl methacrylate, acrylonitrile, methacrylonitrile, butyl acrylate, butadiene and the like. Where desired, the graft copolymerization may be carried out in the presence of two or more styrene type compounds.
As regards the percentage composition of the graft copolymer to be used in the flame-retardant compositions (II) and (III) of the present invention, a graft copolymer having 20 to 200 parts by weight of a styrene type compound grafted onto 100 parts by weight of a polyphenylene ether is advantageously used. If the proportion of the styrene type compound is less than the lower limit of 20 parts by weight, it is difficult to substantially avoid survival of unaltered homopolymer of the polyphenylene ether. If the proportion exceeds the upper limit of 200 parts by weight, the characteristic of the present invention cannot be manifested to full advantage because the thermal resistance, tensile strength and other features due to the presence of the polyphenylene ether component are degraded.
The term "styrene type polymer" as used in connection with the flame-retardant compositions (II) and (III) is meant to embrace polymers preponderantly comprising styrene type compounds of which the number-average molecular weights fall in the range of from 50,000 to 200,000, preferably from 60,000 to 150,000. The "styrene type compounds" referred to here are identical to those which are used in the aforementioned graft copolymerization. Such styrene type polymers further embrace generally known styrene type resins reinforced with rubber. For example, rubber-reinforced polystyrene resins (e.g., of the types mentioned above), acrylonitrile-butadiene-styrene copolymer resins, and the like are embraced in the styrene type polymers for use in the present invention. The proportion of the styrene type polymer (including the styrene type polymer chemically bound onto the polyphenylene ether in consequence of the graft copolymerization) to the whole resin component is in the range of 20 to 80% by weight, preferably from 25 to 75% by weight. If the content of the styrene type polymer is less than the lower limit of 20% by weight, the styrene type polymer fails to impart ample fabricability to the resultant composition. If the content is greater than the upper limit of 80% by weight, the styrene type polymer may be unable, depending upon the condition of mixture thereof with a flame-retarding agent such as an organic phosphorus compound of the present invention, to confer the desired flame-retardancy upon the resultant composition. If the number average molecular weight of the styrene type polymer is below 50,000, there is the disadvantage that the physical properties of the resultant resin, particularly impact strength and creep properties, are deficient. If it exceeds 200,000, however, there ensues an adverse effect upon the moldability and fabricability, which results in various undesirable phenomena such as thermal deterioration of the composition at the time of fabrication and inferior impact resistance of the shaped article due to residual strain.
Concrete examples of the phosphorus-containing compounds represented by the general formula (B) and used in the flame-retardant compositions (I), (II) and (III) of the present invention are shown below by structural formula. ##STR12##
The phosphorus-containing compounds enumerated above are known to the art. A method for the manufacture of these phosphorus-containing compounds is disclosed in U.S. Pat. No. 3,702,878. For the effect of the present invention to be manifested advantageously, the content of the phosphorus-containing compound in the flame-retardant composition (I) is in the range of from 3 to 15% by weight, preferably from 5 to 12% by weight based on the whole composition. If the content of the phosphorus-containing compound is less than the lower limit of 3% by weight, the compound fails to impart self-extinguishing properties and non-dripping properties as found acceptable by the testing method UL-94 to the resultant composition. If the content exceeds the upper limit of 15% by weight, the compound fails to enable the resultant resin composition to retain its properties, particularly the temperature of deflection under load the impact strength, in the practical working ranges. Thus, any deflection of the content from said range proves to be undesirable.
Concrete examples of the aromatic organophosphoric acid esters and aromatic organophosphorous acid esters referred to with respect to the flame-retardant composition (III) of the present invention are tricresyl phosphate, triphenyl phosphate, trixylyl phosphate, cresyl disphenyl phosphate, xylyl-diphenyl phosphate, octyl-diphenyl phosphate, triphenyl phosphite, tricresyl phosphite, trixylyl phosphite, tris (cyclohexyl-phenyl) phosphite, cresyl-diphenyl phosphite, xylyl-diphenylphosphite, and the like.
Concrete examples of the triazole ring-containing compounds as used in this invention include melamine, melamine having 1 to 6 N--H groups thereof methylolated, e.g., dimethylol melamine, trimethylol melamine and hexamethylol melamine, melamine having 1 to 6 N--H groups thereof methylolated and having the methylolated N--H groups further etherified partially or wholly, by methyl, ethyl, propyl or butyl alcohol, e.g., hexamethylol melamine hexamethyl ether, trimethylol melamine tributyl ether and tetramethylol melamine dimethyl ether, benzoguanamine, a benzoguanamine having 1 to 4 N--H groups thereof methylolated, e.g., monomethylol benzoguanamine, tetramethylol benzoguanamine, a benzoguanamine having 1 to 4 N--H groups thereof methylolated and having the methylolated N--H groups thereof methylolated and having the methylolated N--H groups further etherified partially or wholly by methyl, ethyl, butyl or propyl, e.g., tetramethylol guanamine tetramethyl ether and the like.
In flame-retardant composition (II) of the present invention, the content of the phosphorus-containing compound (B) is 2 to 20% by weight compared to 80 to 98% by weight of the resin component. In the flame-retardant composition (III), the content of heterocyclic phosphorus compound is 1 to 18% by weight compared to 80 to 98% by weight of the resin component. In the latter composition having the heterocyclic phosphorus-containing compound content of 1 to 18% by weight, there is additionally incorporated 1 to 18% by weight of at least one compound selected from the group consisting of aromatic organophosphoric acid esters and aromatic organophosphorous acid esters or 1 to 18% by weight of a triazole ring-containing compound (C). Otherwise, the composition can comprise 80 to 98% by weight of the resin component, 1 to 18% by weight of the phosphorus-containing compound, 1 to 18% by weight of either an aromatic organophosphoric acid ester or an aromatic organophosphorous acid ester and 1 to 18% by weight of a triazine ring-containing compound.
For the flame-retardant composition (III) of the present invention to manifest its effect to full advantage, its total content of one or two flame-retarding agents selected from the group consisting of heterocyclic phosphorus-containing compounds, aromatic organophosphoric acid esters, aromatic organophosphorous acid esters and triazine ring-containing compounds is selected in the range of from 2 to 20% by weight, preferably from 3 to 18% by weight, based on the whole flame-retardant composition (III). If the content of the flame-retarding agent is less than the lower limit 2% by weight, the agent fails to impart the self-extinguishing properties and non-dripping properties to the resultant composition. If the content exceeds the upper limit 20% by weight, the agent fails to enable the resultant composition to retain the properties, particularly the temperature of deflexion under load and impact strength, within the practical working ranges.
The method used for the production of the flame-retardant composition (I), (II), or (III) of the present invention is not critical, i.e., the components may be mixed by any method effective for the purpose. One typical example of the methods advantageously available comprises the steps of thoroughly mixing the resin destined to form the backbone of the final composition with the phosphorus-containing compound and further with the flame-retarding agent comprising an aromatic organophosphoric acid ester, an aromatic organophosphorous acid ester and/or a triazine ring-containing compound in a dry blender, melting and kneading the mixture in an extruder and molding the molten mixture into pellets.
Needless to say, it is permissible to incorporate in the flame-retardant composition (I), (II) or (III) of the present invention other additives such as, for example, a plasticizer, a pigment, a reinforcing agent, a filler, an extender and a stabilizer as occasion demands.
Now, the present invention will be described more specifically with reference to examples thereof. Whenever there are mentioned parts and percents, they always mean parts by weight and percents by weight.
The composition can comprise, consist essentially of or consist of the materials set forth.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
EXAMPLE 1
In a blender, 40 parts of poly(2,6-dimethylphenylene-1,4-ether) having a number-average molecular weight of 18,000, 60 parts of a rubber-reinforced styrene-acrylonitrile copolymer having an average acrylonitrile content of 5% and a styrene-butadiene copolymer rubber content of 10% and 8 parts of a phosphorus-containing compound of the following formula: ##STR13## were thoroughly mixed. The resultant mixture was melted and kneaded in an extruder maintained at 220° to 280° C. to produce pellets. The resin mixture thus obtained was capable of being injection molded under the conditions of 250° C. and 600 kg/cm 2 . The physical properties it was found to possess were tensile strength 460 kg/cm 2 (by ASTM method D638, which method was also employed in the examples hereinafter), 12.5 kg·cm/cm Izod impact strength (by ASTM method D256, which method was also employed in the examples hereinafter) and 91.5° C. temperature of deflection under load (by ASTM method D-648, which method was also employed in the examples hereinafter). The resin mixture of this example was tested for inflammability by the UL-94 method. The ignition time was found to be at most 9.2 seconds and 1.6 seconds on the average. In the creep test under tension which was performed at 23° C. under a load of 210 kg, the amount of creep after 1,000 hours of test was 1.04%.
EXAMPLE 2
In a blender, 50 parts of poly(2,6-dimethylphenylene-1,4,-ether) having a number-average molecular weight of 21,000, 50 parts of a rubber-reinforced polystyrene containing 8% of polybutadiene and 8 parts of a phosphorus-containing compound of the following formula: ##STR14## were thoroughly mixed. The resultant mixture was melted and kneaded in an extruder maintained at 280° C. to produce pellets. The resin mixture thus obtained was capable of being injection molded under the conditions of 260° C. and 650 kg/cm 2 . The properties it was found to possess were 560 kg/cm 2 tensile strength, 9.7 kg·cm/cm Izod impact strength and 100.5° C. temperature of deflection under load. In the test for inflammability by the method of UL-94 method, the ignition time was found to be at most 5.0 seconds and 1.8 seconds on the average. Thus, the product was in the V-0 grade. In the creep test under tension which was performed at 60° C. under a load of 105 kg in one test run and at 23° C. under a load of 210 kg in another test run the amounts of creep after 1,000 hours were 0.68% and 0.98% respectively.
EXAMPLE 3
In an extruder maintained at 220° to 280° C., a resin component consisting of 60 parts of poly(2,6-dimethylphenylene-1,4-ether) having a number-average molecular weight of 9,500, 20 parts of a polystyrene-grafted polybutadiene containing 50% of polybutadiene and 20 parts of a polystyrene having a number-average molecular weight of 105,000 was melted and blended to form pellets. In a blender, 100 parts of the pellets and 6 parts of a phosphorus-containing compound of the following formula: ##STR15## were thoroughly mixed. The resultant mixture was melted and kneaded in an extruder maintained at 200° to 260° C. The resin composition thus obtained was capable of being injection molded under the conditions of 280° C. and 600 kg/cm 2 . The properties it was found to possess were 620 kg/cm 2 tensile strength, 18.5 kg·cm/cm Izod impact strength and 112° C. of temperature of deflection under load. In the test for inflammability by the method of UL-94 method, the ignition time was found to be at most 4.9 seconds and 2.7 seconds on the average. Thus, the product was in the V-0 grade. In the creep test under tension which was performed at 60° C. under a load of 105 kg in one test run and at 23° C. under a load of 210 kg in a second test, the amounts of creep after 1,000 hours were 0.46% and 0.83% respectively.
EXAMPLE 4
In a blender, 100 parts of the resin mixture pellets obtained in Example 3 and 5 parts of a phosphorus-containing compound of the following formula: ##STR16## were thoroughly mixed. Then the mixture was melted and kneaded in an extruder. The resin composition thus obtained was capable of being injection molded under the conditions of 280° C. and 550 kg/cm 2 . The physical properties it was found to possess were 590 kg/cm 2 tensile strength, 11.8 kg·cm/cm Izod impact strength and 109.5° C. temperature of deflection under load. In the test for inflammability by the method of UL-94 method, the ignition time was at most 7.4 seconds and 3.1 seconds on the average. The product, thus, was in the V-0 grade. In the creep test under tension which was performed at 60° C. under a load of 105 kg, the amount of creep after 1,000 hours was 0.58%.
EXAMPLE 5
In a Brabender, 100 parts of the resin mixture pellets obtained in Example 3 and 5 parts of a phorphorus-containing compound the following formula: ##STR17## were melted and kneaded at 250° C. for 20 minutes. The resin composition consequently obtained was shown to have a melt index of 3.3 g/10 min. (at 250° C. under a load of 10 kg by the ASTM mehod D1238, which method was also employed in the examples hereinafter). The physical properties it was found to possess were 580 kg/cm 2 of tensile strength, 12.3 kg·cm/mc of Izod impact strength and 111° C. of temperature of deflection under load. In the test for inflammability by the method of UL-94 method, the ignition time was at most 9.5 seconds and 4.3 seconds on the average. Thus, the product was in the V-0 grade. In the creep test under tension which was performed at 60° C. under a load of 105 kg, the amount of creep after 1,000 hours was 0.66%.
EXAMPLE 6
In a blender, 100 parts of the resin mixture pellets obtained in Example 3 and 5 parts of a phorphorus-containing compound of the following formula: ##STR18## were thoroughly mixed. Then, the mixture was melted and kneaded in an extruder maintained at 220° to 260° C. The resin composition thus obtained was capable of being injection molded under the conditions of 280° and 600 kg/cm 2 . The physical properties it was found to possess were 600 kg/cm 2 tensile strength, 14.5 kg·cm/cm Izod impact strength and 115° C. temperature of deflection under load. In the test for inflammability by the UL-94 method, the ignition time was at most 8.6 seconds and 4.1 seconds on the average. Thus, the product was in the V-0 grade. In the creep test under tension which was performed at 60° C. under a load of 105 kg in one test run at 23° C. under a load of 210 kg in another test run, the amounts of creep after 1,000 hours were 0.39% and 0.79% respectively.
EXAMPLE 7
In a blender, 80 parts of poly(2,6-dimethylphenylene-1,4-ether) having a number-average molecular weight of 13,000, 12 parts of a polystyrene grafted polybutadiene containing 50% of polybutadiene, 8 parts of a polystyrene having a number-average molecular weight of 120,000 and 12 parts of a phosphorus-containing compound of the following formula: ##STR19## were thoroughly mixed. Then, the mixture was melted and kneaded in an extruder maintained at 230° to 290° C. to produce pellets. The resultant resin mixture composition was capable of being injection molded under the conditions of 280° C. and 750 kg/cm 2 . The physical properties it was found to possess were 710 kg/cm 2 tensile strength, 15.5 kg·cm/cm Izod impact strength, 143° C. temperature of deflection under load and 1.4 g/10 min. melt index. In the test for inflammability by the UL-94 method, the ignition time was at most 2.1 seconds and 0.8 seconds on the average. Thus, the product was in the V-0 grade. In the creep test under tension which was performed at 60° C. under a load of 105 kg, the amount of creep after 1,000 hours was 0.33%.
EXAMPLE 8
In a blender, 25 parts of poly(2,6-dimethylphenylene-1,4-ether) having a number-average molecular weight of 8,800, 60 parts of a polystyrene having a number-average molecular weight of 105,000 and 10 parts of a phorphorus-containing compound of the following formula: ##STR20## were mixed. Then, the mixture was melted and kneaded in an extruder maintained at 200° to 240° C. Then, in an extruder kept at 200° to 240° C., 95 parts of the resultant composition and 15 parts of a polystyrene grafted polybutadiene containing 50% of polybutadiene were melted and kneaded. The resin composition thus obtained was capable of being injection molded under the conditions of 240° C. and 500 kg/cm 2 . The physical properties it was found to possess were 380 kg/cm 2 tensile strength, 22.6 kg·cm/cm Izod impact strength and 86.3° C. temperature of deflection under load. In the test for inflammability by the UL-94 method, the ignition time was at most 11.3 seconds and 4.9 seconds on the average. Thus, the product was in the V-1 grade. In the creep test under tension which was performed at 23° C. under a load of 210 kg, the amount of creep after 1,000 hours was 1.19%.
EXAMPLE 9
In a blender, 20 parts of poly(2,6-dimethylphenylene-1,4-ether) having a number-average molecular weight of 16,500, 80 parts of a rubber-reinforced polystyrene containing 9.6% of polybutadiene and 8 parts of a phosphorus-containing compound of the following formula: ##STR21## were thoroughly mixed. The mixture was then melted and kneaded in an extruder maintained at 190° to 230° C. The resin thus obtained was capable of being injection molded under the conditions of 235° C. and 500 kg/cm 2 . The physical properties it was found to possess were 365 kg/cm 2 tensile strength, 19.5 kg·cm/cm Izod impact strength and 86.3° C. temperature of deflection under load. In the test for inflammability by the UL-94 method, the ignition time was at most 16.9 seconds and 9.8 seconds on the average. Thus, the product was in the V-1 grade. In the creep test under tension which was performed at 23° C. under a load of 210 kg, the amount of creep after 1,000 hours was 1.25%.
EXAMPLE 10
There was uniformly dissolved in 220 parts of toluene by agitation at 100° C. for 30 minutes, 75 parts of poly(2,6-dimethylphenylene-1,4-ether) having a number-average molecular weight of 12,500 and 3.5 parts of a phosphorus-containing compound of the following formula: ##STR22## Under normal pressure, toluene was distilled out of the mixture. The remaining mixture was dried at 120° C. under 15 mm Hg for three hours. In a Brabender, 78.5 parts of the resultant dry polymer and 25 parts of a polystyrene grafted polybutadiene containing 30% of polybutadiene were melted and kneaded at 270° C. for 15 minutes. The resultant resin composition was shown to have a melt index of 1.1 g/10 min. The physical properties it was found to possess were 720 kg/cm 2 tensile strength, 23.5 kg·cm/cm Izod impact strength and 132.5° C. temperature of deflection under load. In the test for inflammability by the method of UL-94 method, the ignition time was 11.9 seconds at most and 6.4 seconds on the average. Thus, the product was in the V-1 grade. In the creep test under tension which was performed at 60° C. under a load of 105 kg, the amount of creep after 1,000 hours was 0.45%.
EXAMPLES 11-15
There were melted and kneaded in an extruder, 30 parts of poly(2,6-dimethylphenylene-1,4-ether) having a number-average molecular weight of 9,000 and 70 parts of a rubber-reinforced polystyrene containing 8.5% of polybutadiene were melted and kneaded, to form pellets. In a Brabender, 100 parts of the pellets and a varying amount (3 to 11 parts) of a phosphorus-containing compound of the following formula: ##STR23## were kneaded at 240° C. for 20 minutes, to produce compression-molded test pieces. The varying test pieces thus obtained were subjected to test for inflammability by the UL-94 method.
Table 1______________________________________Example 11 12 13 14 15______________________________________Content of phosphorus- 3 5 7 9 11containingcompound (%)Ignition time Maximum 26.1 18.0 9.7 4.1 2.5(seconds) Average 17.7 8.5 4.9 2.2 1.2Grade of inflammability by V-1 V-1 V-0 V-0 V-0UL-94______________________________________
Comparison Examples 1-3
A mixture consisting of 15 parts of poly(2,6-dimethylphenylene-1,4-ether) having a number-average molecular weight of 16,500 and 85 parts of a rubber-reinforced polystyrene containing 9.6% of polybutadiene was melted and kneaded with a varying amount (6 to 12 parts) of a phosphorus-containing compound of the following formula: ##STR24## and the resultant mixture was compression molded. The resin compositions thus obtained were tested for inflammability by the method of UL-94 method. The results are collectively shown in Table 2.
Table 2______________________________________Comparison Example 1 2 3______________________________________Content of phosphorus-containing 6 9 12compound (%)Ignition time (seconds) Maximum 41.5 22.5 10.8 Average 26.5 14.0 6.2Dripping property YES YES YESGrade of inflammability by UL-94 -- V-2 V-2______________________________________
Comparison Example 4
The procedure of Example 2 was repeated, except the amount of the phosphorus-containing compound was decreased to 2.5 parts. The resultant resin mixture was capable of being injection molded under the conditions of 280° C. and 650 kg/cm 2 . The physical properties it was found to possess were 590 kg/cm 2 tensile strength, 6.3 kg·cm/cm Izod impact strength and 113° C. temperature of deflection under load. In the test for inflammability by the method of UL-94 method, the ignition time was at most 38.6 seconds and 20.9 seconds on the average. Thus, the product was not of flame-retardant grade.
Comparison Examples 5-7
The procedure of Example 2 was repeated, except the amount of the phosphorus-containing compound was increased to 20 parts (in Comparison Example 5). It was further repeated, except the amount of the poly(2,6-dimethylphenylene-1,4-ether) in 100 parts of the resin component was increased to 65 parts in one test run and to 80 parts in the others (Comparison Examples 6 and 7). The resultant resin compositions were injection molded and then tested for physical properties and inflammability. The results are collectively shown in Table 3. The results indicate that an excess of the content of the phosphorus-containing compound brings about the disadvantage that the final resin composition suffers from serious degradation in impact strength and temperature of deflection under load even to a point where the phenomenon of dripping occurred during the combustion.
Table 3______________________________________Comparison Example 5 6 7______________________________________Content of polyphenylene ether (parts) 50 65 80Izod impact strength (kg.cm/cm) 3.8 2.4 2.1Temperature of deflection under load (°C.) 58.5 71.0 81.5Ignition time (seconds) Maximum 3.5 2.0 1.0 Average 1.9 0.8 0.5Dripping property YES YES YES______________________________________
Comparison Example 8
The procedure of Example 7 was repeated, except the amount of the polyphenylene ether in 100 parts of the resin component was increased to 93 parts. The resultant mixture resin failed to affort any satisfactory injection-molded test piece even under the conditions of 300° C. and 900 kg/cm 2 . The physical properties obtained of the compression-molded test piece were 750 kg/cm 2 tensile strength, 2.5 kg·cm/cm Izod impact strength, 155° C. temperature of deflection under load and 0.2 g/10 min. melt index. The results indicate that an excess of the content of the polyphenylene ether is disadvantageous.
EXAMPLE 16
In an autoclave, 50 parts of poly(2,6-dimethylphenylene-1,4-ether) having a number-average molecular weight of 11,000, 20 parts of styrene and 30 parts of ethyl benzene were uniformly dissolved by agitation under heating at 100° C. for one hour. To the resultant mixture was added a mixed solution consisting of 20 parts of ethyl benzene and 2 parts of di-tert.-butyl peroxide, followed by displacement of the oxygen gas present in the autoclave with nitrogen gas. The temperature of the resultant mixture in the autoclave was gradually elevated to 140° to 145° C., at which temperature the mixture was kept under agitation for 2.5 hours to induce a reaction. This treatment brought the polymerization of styrene to substantial completion. The reaction mixture was removed from the autoclave, dried in a vacuum drier at 200° C. for two hours to expel the solvent. Thus there was obtained a graft copolymer.
By assay of the graft copolymer through infrared absorption spectrometry, the copolymer was found to have a polystyrene content of 27%.
Separately, a rubber latex containing 50 parts of polybutadiene was agitated with a mixed solution consisting of 60 parts of sytrene, 0.3 part of tert.-dodecylmercaptan, 0.5 part of sodium laurylsulfate, 0.05 part of potassium persulfate and 400 parts of deionized water at 70° C. for eight hours to induce polymerization. The latex thus obtained was salted out, washed and dried to afford a polymer, i.e. a rubber-modified polystyrene, in the form of flakes. By assay through infrared absorption spectrometry, the polymer was found to have a polybutadiene content of 47%.
In a blender, 60 parts of said polyphenylene either graft copolymer, 16 parts of said rubber-modified polystyrene, 17 parts of polystyrene (sold by Asahi-Dow Ltd. under tradename of Styron 683) and 7 parts of a phosphorus-containing compound of the following formula: ##STR25## were thoroughly mixed. The resultant mixture was melted and kneaded in an extruder maintained at 220° to 280° C., to form pellets.
In the preparation of test pieces for determination of physical properties by use of an injection molding machine, Model IS50A, made by Toshiba Machine Co., Ltd. (the same molding conditions were employed in examples hereinafter), the resin mixture thus obtained was capable of being injection molded under the conditions of 235° C. and 450 kg/cm 2 . The physical properties possessed by the resin were 510 kg/cm 2 tensile strength, 28% elongation at rupture, 12.5 kg·cm/cm Izod impact strength and 108° C. temperature of deflection under load. The resin had a smooth surface. The resin mixture of this Example was tested for inflammability by the UL-94 method. The ignition time was at most 6.1 seconds and 1.6 seconds on the average.
EXAMPLE 17
In a blender, 30 parts of polyphenylene ether graft copolymer used in Example 16, 59 parts of the rubber-reinforced polystyrene (sold by Asahi-Dow Ltd. under tradename of Styron 492) and 11 parts of a phosphorus-containing compound of the following formula: ##STR26## were mixed. Then, the mixture was melted and kneaded in an extruder maintained at 210° to 220° C., to form a resin mixture composition in the form of pellets. This resin was capable of being injection molded under the conditions of 215° C. and 400 kg/cm 2 . It exhibited a tensile strength of 320 kg/cm 2 , an Izod impact strength of 10.8 kg·cm/cm, a temperature of deflection under load of 85° C. and an ignition time of at most 9.8 seconds and 2.9 seconds on the average.
EXAMPLE 18
In a blender, a resin component consisting of 50 parts of the polyphenylene ether graft copolymer used in Example 16, 8 parts of a rubber-modified polystyrene and 31 parts of Styron 492 was mixed with a flame-retarding agent consisting of 3 parts of a phosphorus-containing compound of the following formula: ##STR27## 3 parts of tetramethylolated melamine and 5 parts of tricresyl phosphate. The resultant mixture was melted and kneaded in an extruder, to form pellets. The resin was capable of being injection molded under the conditions of 230° C. and 400 kg/cm 2 . The physical properties possessed by the resin were 420 kg/cm 2 tensile strength, 32% elongation at rupture, 9.3 kg·cm/cm Izod impact strength and 102° C. temperature of deflection under load. In the test for inflammability, the ignition time was at most 4.2 seconds and 1.5 seconds on the average.
EXAMPLE 19
In a blender, 65 parts of the polyphenylene ether graft copolymer used in Example 16, 15 parts of rubber-modified polystyrene, 10 parts of Styron 690, 2 parts of a phsophorus-containing compound of the following formula: ##STR28## and 6 parts of triphenyl phosphate were mixed. The resultant mixture was melted and kneaded in an extruder. The resin thus obtained was capable of being injection molded under the conditions of 240° C. and 450 kg/cm 2 . The physical properties possessed by this resin were 580 kg/cm 2 tensile strength, 50% elongation at rupture, 23.0 kg·cm/cm Izod impact strength and 112° C. temperature of deflection under load. In the test for inflammability, the ignition time was at most 8.8 seconds and 3.5 seconds on the average. Thus, this product was in the V-0 grade.
EXAMPLE 20
A polyphenylene ether graft copolymer was obtained by following the procedure of Example 16, except there were used 30 parts of poly(2,6-dimethylphenylene-1,4-ether) having a number-average molecular weight of 21,000 and 40 parts of styrene. By the assay through the infrared absorption spectrometry, the copolymer was found to have a polystyrene content of 56%.
In a blender, 50 parts of the graft copolymer, 10 parts of the rubber-modified polystyrene used in Example 16, 30 parts of Styron 492, 3 parts of the heterocyclic phosphorus-containing compound used in Example 19, 2 parts of dimethylolated bezoguanamine and 5 parts of triphenyl phosphate were mixed. The resultant mixture was melted and kneaded in an extruder. The mixture resin thus obtained was capable of being injection molded under the conditions of 225° C. and 400 kg/cm 2 . The physical properties possessed by the resin were 380 kg/cm 2 tensile strength, 35% elongation at rupture, 13.3 kg·cm/cm Izod impact strength and 83° C. temperature of deflection under load. In the test for inflammability, the ignition time was at most 3.5 seconds and 1.2 seconds on the average.
EXAMPLE 21
In a blender, 45 parts of polyphenylene ether graft copolymer used in Example 20, 6 parts of the rubber-modified polystyrene used in Example 16, 40 parts of Styron 492, 2.5 parts of a phosphorus-containing compound of the following formula: ##STR29## and 6.5 parts of 75% butylated tetramethylol benzoguanamine were mixed. Then, the resultant mixture was melted and kneaded in an extruder. The resin thus obtained was capable of being injection molded under the conditions of 220° C. and 450 kg/cm 2 . The physical properties possessed by this resin were 340 kg/cm 2 tensile strength, 30% elongation at rupture, 11.9 kg.cm/cm Izod impact strength and 101° C. temperature of deflection under load. In the test for inflammability, the ignition time was at most 18.4 seconds and 9.3 seconds on the average.
EXAMPLE 22
In a blender, 70 parts of the polyphenylene ether graft copolymer used in Example 20, 14 parts of the rubber-modified polystyrene used in Example 16 and 16 parts of the heterocyclic phosphorus-containing compound used in Example 19 were mixed. Then the resultant mixture was heated and kneaded in an extruder. The resin mixture thus obtained was capable of being injection molded under the conditions of 210° C. and 300 kg/cm 2 . The physical properties possessed by this resin were 410 kg/cm 2 tensile strength, 26% elongation at rupture, 9.0 kg·cm/cm Izod impact strength and 80° C. temperature of deflection under load. In the test for inflammability, the ignition time was at most 3.0 seconds and 1.0 second on the average.
EXAMPLE 23
In a blender, 90 parts of the polyphenylene ether graft copolymer used in Example 20, 7.8 parts of the rubber-modified polystyrene used in Example 16, 1.2 parts of a phosphorus-containing compound of the formula: ##STR30## and 1.0 part of trixylyl phosphate were mixed. Then, the resultant mixture was melted and kneaded in an extruder. The resin mixture thus obtained was capable of being injection molded under the conditons of 240° C. and 450 kg/cm 2 . The physical properties possessed by this resin were 540 kg/cm 2 tensile strength, 20% elongation at rupture, 6.9 kg·cm/cm Izod impact strength and 116° C. temperature of deflection under load. In the test for inflammability, the ignition time was at most 16.6 seconds and 5.8 seconds on the average.
EXAMPLE 24
In a blender, 60 parts of the polyphenylene ether graft copolymer used in Example 16, 15 parts of a rubber-modified polystyrene, 20 parts of the polyphenylene ether graft copolymer used in Example 20, 3 parts of the heterocyclic phosphorus-containing compound used in Example 19 and 2 parts of trimethylolated melamine were mixed. Then, the resultant mixture was melted and kneaded in an extruder. The resin thus obtained was capable of being injection molded under the conditions of 240° C. and 500 kg/cm 2 . The physical properties possessed by this resin were 550 kg/cm 2 tensile strength, 42% elongation at rupture, 16.0 kg·cm/cm Izod impact strength and 131° C. temperature of deflection under load. In the test for inflammability, the ignition time was at most 10.3 seconds and 4.2 seconds on the average.
EXAMPLE 25
A mixture consisting of 70 parts of the poly(2,6-dimethylphenylene-1,4-ether) used in Example 16 and 15 parts of pulverized polystyrene (sold by Asahi-Dow Ltd. under tradename of Styron 683) and a mixed solution consisting of 2.0 parts of di-tert.-butyl peroxide and 15 parts of styrene were mixed to produce a homogeneous mixture. This mixture was fed to an extruder maintained at 150 to 230° C., in which it was melted and kneaded to undergo graft polymerization. As a result, there was obtained a polyphenylene ether graft copolymer. By assay through infrared absorption spectrometry, this graft copolymer was found to have a polystyrene content of 28%. In a blender, 85 parts of the graft copolymer, 10 parts of the rubber-modified polystyrene used in Example 16, 2 parts of the heterocyclic phosphorus-containing compound used in Example 19, 1 part of dimethylolated melamine and 2 parts of tricresyl phosphate were mixed. Then the resultant mixture was melted and kneaded in an extruder maintained at 220° to 270° C. The resin mixture thus obtained was capable of being injection molded under the conditions of 240° C. and 500 kg/cm 2 . The physical properties possessed by this resin were 570 kg/cm 2 tensile strength, 35% elongation at rupture, 7.7 kg·cm/cm Izod impact strength and 139° C. temperature of deflection under load. In the test for inflammability, the ignition time was at most 12.2 seconds and 5.6 seconds on the average.
EXAMPLE 26
In a blender, a resin component consisting of 60 parts of the polyphenylene ether graft copolymer used in Example 25, 14 parts of Styron 492 and 10 parts of the rubber-modified polystyrene used in Example 16 and a flame-retarding agent consisting of 2 parts of the phosphorus-containing compound used in Example 16, 13 parts of hexamethoxymethylol melamine (sold by Sumitomo Chemical Co., Ltd. under tradename of Sumimarl M-100) and 1 part of triphenyl phosphate were simultaneously mixed. Then, the resultant mixture was melted and kneaded in an extruder. The resin thus obtained was capable of being injection molded under the conditions of 235° C. and 400 kg/cm 2 . The physical properties possessed by this resin were 510 kg/cm 2 tensile strength, 22% elongation at rupture, 10.5 kg·cm/cm Izod impact strength and 120° C. temperature of deflection under load. In the test for inflammability, the ignition time was at most 9.6 seconds and 3.6 seconds on the average.
EXAMPLE 27
In a blender, 75 parts of the polyphenylene ether graft copolymer used in Example 25, 9.8 parts of the rubber-modified polystyrene used in Example 16, 1.2 parts of the heterocyclic phosphorus-containing compound used in Example 23 and 14 parts of trixylyl phosphate were mixed. Then, the resultant mixture was heated and kneaded in an extruder. The resin mixture thus obtained was capable of being injection molded under the conditions of 220° C. and 400 kg/cm 2 . The physical properties possessed by this resin were 490 kg/cm 2 tensile strength, 26% elongation at rupture, 13.3 kg·cm/cm Izod impact strength and 98.5° C. temperature of deflection under load. In the test for inflammability, the ignition time was at most 6.1 seconds and 2.8 seconds on the average.
EXAMPLE 28
In a blender, 45 parts of the polyphenylene ether graft copolymer used in Example 25, 38.5 parts of Styron 492, 1.5 parts of the heterocyclic phosphorus-containing compound used in Example 19 and 15 parts of tetramethoxymethylol benzoguanamine were mixed. Then, the resultant mixture was melted and kneaded in an extruder. The resin thus obtained was capable of being injection molded under the conditions of 220° C. and 400 kg/cm 2 . The physical properties possessed by this resin were 380 kg/cm 2 tensile strength, 30% elongation at rupture, 8.8 kg·cm/cm Izod impact strength and 111° C. temperature of deflection under load. In the test for inflammability, the ignition time was at most 19.5 seconds and 8.2 seconds on the average.
EXAMPLE 29
In a blender, 80.5 parts of the polyphenylene ether graft copolymer used in Example 25, 10 parts of the rubber-modified polystyrene used in Example 16, 8 parts of the heterocyclic phosphorus-containing compound used in Example 19 and 1.5 parts of pentamethylolated melamine were mixed. Then, the resultant mixture was melted and kneaded in an extruder. The resin mixture composition thus obtained was capable of being injection molded under the conditions of 230° C. and 400 kg/cm 2 . The physical properties possessed by this resin were 560 kg/cm 2 tensile strength, 40% elongation at rupture, 9.8 kg·cm/cm Izod impact strength and 125° C. temperature of deflection under load. In the test for inflammability, the ignition time was at most 8.2 seconds and 3.3 seconds on the average.
EXAMPLE 30
A mixture consisting of 30 parts of the polyphenylene ether graft copolymer used in Example 16 and 20 parts of the polyphenylene ether graft copolymer used in Example 25 was mixed with 40 parts of Styron 492 to produce a resin component. In a blender, this resin component was throughly mixed with a flame-retarding agent consisting of 1 part of a phosphorus-containing compound of the following formula: ##STR31## 8 parts of tetramethylolated benzoguanamine and 1 part of cresyldiphenyl phosphate. Then, the resultant mixture was melted and kneaded in an extruder. The resin mixture composition thus obtained was capable of being injection molded under the conditions of 220° C. and 450 kg/cm 2 . The physical properties possessed by this resin composition were 420 kg/cm 2 tensile strength, 20% elongation at rupture, 6.6 kg·cm/cm Izod impact strength and 112° C. temperature of deflection under load. In the test for inflammability, the ignition time was at most 14.3 seconds and 6.0 seconds on the average.
EXAMPLE 31
In an autoclave, 50 parts of poly(2,6-dimethylphenylene-1,4-ether) having a number-average molecular weight of 12,000, 18 parts of styrene, 2 parts of acrylonitrile and 30 parts of ethyl benzene were agitated under heating at 100° C. for one hour to provide a homogeneous solution. To the resultant mixture there was added a mixed solution consisting of 20 parts of ethyl benzene and 2 parts of di-tert.-butyl peroxide, followed by displacement of the oxygen gas present in the autoclave interior with nitrogen gas. The temperature of the resultant mixture in the autoclave was gradually elevated to 140 to 150° C., at which temperature the mixture was agitated for two hours to induce a reaction. By this treatment, polymerization of styrene and acrylonitrile was brought to substantial completion. The polymerization product was removed from the autoclave and, dried in a vacuum drier to afford a graft copolymer. By assay through infrared absorption spectrometry, the graft copolymer was found to have a polyphenylene ether content of 73%.
In a blender, 55 parts of the graft copolymer mentioned above, 45 parts of a rubber-modified styrene-acrylonitrile copolymer having an average acrylonitrile content of 13% and a styrene-butadiene copolymer rubber content of 14%, 4 parts of the heterocyclic phosphorus-containing compound used in Example 19 and 3 parts of tricresyl phosphate were mixed. Then, the resultant mixture was melted and kneaded in an extruder. The resin mixture composition thus obtained was capable of being injection molded under the conditions of 230° C. and 450 kg/cm 2 to produce shaped articles of a homogeneous texture. The physical properties possessed by this resin were 450 kg/cm 2 tensile strength, 40% elongation at rupture, 14.9 kg·cm/cm Izod impact strength and 104° C. temperature of deflection under load. In the test for inflammability, the ignition time was at most 9.6 seconds and 4.2 seconds on the average.
EXAMPLE 32
In a blender, 28 parts of the polyphenylene ether graft copolymer used in Example 31, 22 parts of a rubber-reinforced styrene-acrylonitrile copolymer having an average acrylonitrile content of 18% and a styrene-butadiene copolymer rubber content of 10%, 50 parts of Styron 492, 5 parts of the phosphorus-containing compound used in Example 16 and 2 parts of triphenyl phosphate were mixed. Then, the resultant mixture was melted and kneaded in an extruder. The mixture resin composition thus obtained was capable of being injection molded under the conditions of 220° C. and 400 kg/cm 2 to afford shaped articles of a homogeneous texture. The physical properties possessed by this composition were 330 kg/cm 2 tensile strength, 35% elongation at rupture, 15.5 kg·cm/cm Izod impact strength and 90.5° C. temperature of deflection under load. In the test for inflammability, the ignition time was at most 8.5 seconds and 4.6 seconds on the average.
EXAMPLE 33
A mixture consisting of 60 parts of poly(2, 6-dimethylphenylene-1,4-ether) having a number-average molecular weight of 12,500, 10 parts of a pulverized polystyrene (sold by Asahi-Dow Ltd. under tradename of Styron 690) and 20 parts of ethylene-methyl methacrylate copolymer having a methyl methacrylate content of 12 mol% was mixed with a mixed solution consisting of 2.0 parts of di-tert.-butyl peroxide and 10 parts of styrene to provide a homogeneous solution. The resultant mixture was fed to an extruder maintained at 160° to 220° C., in which the mixture was melted and kneaded to induce graft polymerization. As a result, there was obtained a polyphenylene-ether graft copolymer. By assay through infrared absorption spectrometry, the graft copolymer was found to have a polystyrene content of 19% and an ethylene-methyl methacrylate copolymer content of 20%. In a blender, 75 parts of the graft copolymer mentioned above, 18 parts of Styron 690, 5 parts of the heterocyclic phosphorus-containing compound used in Example 19 and 2 parts of tricresyl phosphate were thoroughly mixed. Then, the resultant mixture was melted and kneaded in an extruder. The resin mixture composition thus obtained was capable of being injection molded under the conditions of 240° C. and 450 kg/cm 2 to afford shaped articles of a homogeneous texture. The physical properties possessed by this composition were 440 kg/cm 2 tensile strength, 50% elongation at rupture, 18.2 kg·cm/cm Izod impact strength and 110° C. temperature of deflection under load. In the test for inflammability, the ignition time was at most 11.5 seconds and 4.9 seconds on the average. | A flame-retardant polyphenylene ether resin composition comprising (I) 85 to 97% by weight of a resin consisting of (1) 20 to 90% by weight of a polyphenylene ether of the formula (A): ##STR1## where R 1 and R 2 are each alkyl of 1 to 4 carbon atoms and m is the degree of polymerization, and (2) 80 to 10% by weight of a styrene type polymer and (II) 3 to 15% by weight of at least one member of the group consisting of phosphorus-containing compounds of formula (B): ##STR2## where X is a hydrogen atom, a hydroxyl group, an amino group, a halogen atom, an alkyl group of 1 to 10 carbon atoms, an alkoxy group of 1 to 10 carbon atoms, an alkylthio of 1 to 10 carbon atoms, an aryloxy of 6 of 10 carbon atoms or hydroxy substituted aryloxy of 6 to 10 carbon atoms, Y 1 and Y 2 are each an alkyl of 1 to 8 carbon atoms, an alkoxy of 1 to 8 carbon atoms or an aryl group, Z is an oxygen or sulfur atom, n and p are each an integer of 0 to 4 and q is an integer of 0 or 1. Similar compositions are also prepared including styrene type compounded grafted to the polyphenylene ether and including organic phosphates and organic phosphites and/or melamine, benzoguanamine or their methylol or etherified methylol derivatives. | 2 |
GOVERNMENT LICENSE RIGHTS
The U.S. Government has a paid-up license in this invention and the right in limited cicumstances to require the patent owner to license others on reasonable terms as provided for by the terms of Contract No. VGART NCC2-99086.
TECHNICAL FIELD
The present invention relates in general to the field of rotor hubs for aircraft. In particular, the present invention relates to a dual spring rate damper for soft in-plane rotor hubs.
DESCRIPTION OF THE PRIOR ART
Many aircraft rotors, especially those for helicopters and tiltrotor aircraft, include a lead/lag hinge designed to allow in-plane motion of a blade about an axis generally normal to the plane of rotation, such that the blade “runs in” or “gets behind” with respect to other blades. This is mainly to compensate for the extra rotational speed that comes with “blade flapping” and to compensate for differences in blade aerodynamic drag encountered at various moments of one rotational cycle.
To prevent excessive motion about the lead/lag hinge, dampers are normally incorporated in the design of this type of rotor system. The purpose of the dampers is to absorb the acceleration and deceleration of the rotor blades and maintain the frequency of the lead/lag motion within a desired range. Often, the damper is an elastomeric damper. Normally, the spring rate chosen for a lead/lag damper is a compromise between the value required for the desired in-plane stiffness and a value that reduces load and fatigue on the rotor and other aircraft components.
SUMMARY OF THE INVENTION
There is a need for an improved apparatus and improved methods for providing switchable in-plane damping for varying the in-plane stiffness of a rotor hub.
Therefore, it is an object of the present invention to provide an improved apparatus and improved methods for providing switchable in-plane damping for varying the in-plane stiffness of a rotor hub.
The present invention provides a damper having a piston, the piston having an axis, an outer surface, and opposing ends. Elastomeric seals are in sealing contact with the outer surface of the piston, the seals being coaxial with the piston and limiting movement of the piston to a path along the axis of the piston. The seals also define fluid chambers adjacent the ends of the piston. A primary passage communicates the fluid chambers, and a selectively switchable valve for controls a flow of fluid from one of the chambers to another of the chambers through the primary passage. When the flow of fluid through the primary passage is permitted, movement of the piston is resisted by a first spring rate due to a shear force required to cause shear deflection of the seals. When the flow of fluid through the primary passage is restricted, movement of the piston is resisted by a second spring rate due to a fluid force required to cause bulging deflection of the seals.
The present invention provides significant advantages over the prior art, including: (1) providing selectively switchable spring rates for lead/lag damping; (2) providing a small, lightweight switchable damper for use in the rotor hubs of the invention; and (3) providing a method of preventing ground resonance conditions while minimizing loads and fatigue on aircraft components.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the present invention, including its features and advantages, reference is now made to the detailed description of the invention taken in conjunction with the accompanying drawings in which like numerals identify like parts, and in which:
FIG. 1 is a perspective view of a four-blade aircraft rotor hub according to the present invention;
FIG. 2 is an exploded perspective view of a three-blade aircraft rotor hub according to the invention;
FIG. 3 is a partially sectioned perspective view of the rotor hub of FIG. 2 ;
FIG. 4 is a cross-sectional plan view of a portion of the rotor hub of FIG. 2 ;
FIG. 5 is a cross-sectional plan view of a dual-spring-rate damper for use in the rotor hubs of the present invention;
FIG. 6 is a cross-sectional plan view of the damper of FIG. 5 , the damper being configured for a softer spring rate; and
FIG. 7 is a cross-sectional plan view of the damper of FIG. 5 , the damper being configured for a stiffer spring rate.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1 in the drawings, a soft in-plane rotor hub 11 according to the present invention is illustrated. As shown, hub 11 is configured as a four-blade hub for use as a proprotor hub of a tiltrotor aircraft. Rotor hubs according to the invention may have more or fewer blades and may also be configured for use on other rotary-wing aircraft, including helicopters.
Hub 11 has a central member 13 which is adapted to fixedly receive mast 15 . Mast, 15 is rotated by torque from a drive unit, which may be routed through a transmission (not shown), and the torque is transferred through mast 15 to central member 13 for rotating hub 11 . Blades (not shown) are attached to hub 11 with blade attachment assemblies 17 , each assembly 17 comprising a blade attachment strap 19 and a blade grip 21 . Straps 19 are circumferential and oriented vertically to extend out of the plane of rotation. Straps 19 are hingedly connected to central member 13 at flapping hinges 23 , and blade grips 21 are rotatably and pivotally attached to the outer end of straps 19 . Flapping hinges 23 allow for out-of-plane flapping motion of each blade about an axis generally parallel to the plane of rotation of hub 11 . Blade grips 21 rotate relative to straps 19 about radial pitch axes that are generally parallel to the plane of rotation of hub 11 , and a pitch horn 25 extends from the leading edge of each grip 21 for controlling the pitch of the associated blade. Pitch horns 25 combine with the associated flapping hinge 23 to yield the desired delta- 3 pitch-flap coupling. In addition, each blade grip 21 is connected to strap 19 with a lead/lag bearing (not shown), and the grip 21 pivots relative to the associated strap 19 about a lead/lag axis generally normal to the plane of rotation of hub 11 . This provides for chordwise, lead and lag motion of the blades in the plane of rotation of hub 11 about the lead/lag axis. Both the bearing for flapping hinge 23 and the lead/lag bearing are located within strap 19 . The flapping hinge axis is located inboard, and the lead/lag axis is located outboard, the axes being non-coincident. Blade roots 27 are shown installed within the outer ends of grips 21 .
To control the chordwise motion of blades about the lead/lag axis, a damper 29 is installed in each strap 19 and is operably connected to the associated blade grip 21 . Dampers 29 are each preferably selectively switchable between at least two spring rates, allowing for hub 11 to be readily configured to have selected in-plane stiffness values. The advantage of selectable in-plane stiffness is that hub 11 can be made stiff enough to prevent ground-resonance conditions when the aircraft is resting on a surface, yet hub 11 can be made softer during flight for minimizing loads and fatigue on components of hub 11 and other components of the aircraft. Dampers 29 are preferably switched through electric actuation, though other types of actuation may alternatively be used, and the switching of dampers 29 is preferably automatically controlled by aircraft control systems. For example, the aircraft control systems may switch dampers 29 to a stiffer setting upon a signal that the aircraft is within a selected proximity of the ground or upon a signal generated by sensors indicating contact of the landing gear with the ground.
FIGS. 2 through 4 show a simplified, three-blade alternative embodiment of a rotor hub of the invention. FIG. 2 is an exploded view, FIG. 3 is a partial cutaway of the assembly, and FIG. 4 is a cross-sectional plan view of the assembly. Referring to the these figures, hub 31 includes central member 33 , blade straps 35 , and blade grips 37 . Central member 33 is adapted to fixedly receive mast 34 . Straps 35 are circumferential and are hingedly connected to central member 33 at flapping hinge 39 . This allows for out-of-plane flapping motion of blades (not shown) attached to blade grips 37 . Each blade grip 37 receives the root end of a blade in the outer end of grip 37 , and the inner end of each grip 37 is connected to the outer end of the associated strap 35 with pitch horn brackets 41 . Each grip 37 can rotate about an associated pitch axis 43 , and the pitch for the blades is controlled using pitch horns 45 on brackets 41 . An elastomeric bearing 47 is received within a recess 49 of each bracket 41 to provide for in-plane, chordwise pivoting of brackets 41 and grips 37 about a lead/lag axis 51 passing through the focus of each bearing 47 . Both elastomeric bearing 47 and flapping hinge 39 are located within strap 35 , with the axes for these hinges being non-coincident. This configuration allow for better packaging of the components of hub 31 , especially in tiltrotor applications.
As hub 31 is rotated by mast 34 , centrifugal loads from the blades are transferred through grips 37 into brackets 41 and from brackets 41 into bearings 47 . The loads are then transferred into straps 35 from bearings 47 and into central member 33 from straps 35 . A post 53 protrudes from the inner end of each bearing 47 , with post 53 extending through a bore 55 in recess 49 of the corresponding bracket 41 . The inner end 57 of post 53 engages a multiple-spring-rate damper 59 , post 53 extending into an opening 61 in the outer wall 63 of damper 59 and engaging piston 65 . Though shown with an elastomeric bearing 47 , hubs of the invention may be constructed in any appropriate configuration, including hubs using pins or similar connections for the lead/lag hinge.
In-plane motion of a blade about the associated lead/lag axis 51 causes a proportional in-plane motion of post 53 . Because post 53 is located inward of axis 51 , the in-plane motion of post 53 is in the direction opposite the movement of the blade. This motion causes displacement of piston 65 along axis 67 , which is resisted by the bulging and/or shearing deflection of elastomeric seals 69 , 71 . Each damper 59 is selectively switchable between at least two spring rates, including while hub 31 is in use, allowing hub 31 to be switched between at least two values of in-plane stiffness.
Damper 59 , as shown in FIG. 4 , is one example of a switchable, multi-spring-rate damper according to the present invention that can be used in hubs of the present invention, though other types of selectively switchable, multiple-spring-rate dampers may be used. A more detailed view of damper 59 is shown in FIGS. 5 through 7 and described below.
Referring to FIG. 5 , damper 59 is shown in a cross-sectional plan view Elastomeric seals 69 , 71 are fixedly mounted to inner surface 73 of housing 75 and fixedly mounted to outer surface 77 of piston 65 . Seals 69 , 71 are preferably formed as “sandwich” structures, with alternating layers of an elastomeric material 79 and a rigid, non-elastomeric material 81 , such as a metal. This type of structure is nearly incompressible in a direction generally normal to the layers, but the structure allows for a limited amount of shearing motion.
Each seal 69 , 71 sealingly engages inner surface 73 and outer surface 77 to form fluid chambers 83 , 85 within housing 75 . Each fluid chamber 83 , 85 is adjacent an end of piston 65 and contains a preferably incompressible fluid, such as a hydraulic fluid or an oil. The fluid may flow between chambers 83 , 85 through passages 87 , 89 , 91 , 93 formed in piston 65 and extending from one end of piston 65 to the other end of piston 65 . A bore 95 is located on outer surface 77 for receiving inner end 57 of post 53 , which extends from elastomeric bearing 47 ( FIG. 2 ).
Primary damping passage 87 has valve means, such as rotary valve 97 , for controlling the flow of fluid through primary passage 87 . As shown in FIG. 5 , valve passage 99 of valve 97 can be aligned with primary passage 87 for allowing fluid to freely flow between chambers 83 , 85 through primary passage 87 . Valve 97 can be rotated between this “open” and a “closed” position, in which valve passage 99 is rotated out of alignment with primary passage 87 , preventing fluid from flowing through passage 87 . A secondary passage 89 , which is preferably smaller in cross-sectional area than passage 87 , extends through piston 65 for communicating chambers 83 , 85 . Secondary passage 89 does not have valve means, so fluid is allowed to flow between chambers 83 , 85 at all times through secondary passage 89 . Bypass passages 91 , 93 also extend through piston 65 and communicate chambers 83 , 85 . Each bypass passage 91 , 93 has a one-way, spring-biased check valve, items 101 and 103 , respectively, for allowing fluid flow through bypass passages 91 , 93 only when an over pressure occurs in one of chambers 83 , 85 . An over pressure in a chamber 83 , 85 will overcome the force of the spring in the opposing check valve 101 , 103 , forcing valve 101 , 103 from a seated position in bypass passage 91 , 93 . Fluid then flows through bypass passage 91 , 93 until the over pressure subsides enough to allow bypass valve 101 , 103 to seat, stopping the flow of fluid.
FIGS. 6 and 7 illustrate damper 59 in operation. Referring to FIG. 6 , damper 59 is shown reacting to a movement of post 53 in the direction shown by arrow 105 when damper is switched to the softer of the two available spring rates. Rotary valve 97 is in the open position, in which valve passage 99 is aligned with passage 87 , and this allows fluid to flow between fluid chambers 83 , 85 through passage 87 . Fluid can also flow between chambers 83 , 85 through passage 89 . When movement of post 53 causes piston 65 to move relative to housing 75 and toward chamber 85 , as is shown in the figure, the movement is resisted by the shear force required to deflect seals 69 , 71 , which are fixedly attached to housing 75 and to piston 65 . The shear force provides a spring rate, k shear , for damper 59 . In addition, the end of piston 65 adjacent chamber 85 applies pressure to the fluid in chamber 85 , forcing the fluid to pass through passages 87 , 89 , which act as a fluid restriction for damping oscillations of piston 65 .
Referring to FIG. 7 , damper 59 is shown reacting to a movement of post 53 in the direction shown by arrow 105 when damper is switched to the stiffer of the two available spring rates. Rotary valve 97 is in the closed position, in which valve passage 99 is out of alignment with passage 87 , and this prevents fluid flow between fluid chambers 83 , 85 through passage 87 . Fluid can flow between chambers 83 , 85 through passage 89 . When movement of post 53 causes piston 65 to move relative to housing 75 and toward chamber 85 , as is shown in the figure, the movement is resisted by the force required to bulgingly deflect seals 71 , as shown. Because fluid in chamber 85 is restricted to flowing through only secondary passage 89 , the fluid pressure caused by piston 65 on the fluid in chamber 85 causes the central portion of seal 71 to bulge outward. The force required provides a spring rate, k bulge , for damper 59 , k bulge , being a higher value than k shear . The flow restriction to fluid flowing through passage 89 damps oscillations of piston 65 .
Dampers of the invention may have one piston, such as damper 59 ( FIG. 4 ), or may have more than one piston, such as damper 29 ( FIG. 1 ). Dampers 29 , 59 preferably have a stroke of approximately ±1.00 in., though dampers 29 , 59 may be constructed in any appropriate size for the particular application. Dampers of the invention are shown as having passages extending through the piston, though passages routed through the damper housing may alternatively be used.
The damper of the invention has several advantages, including: (1) providing selectively switchable spring rates for lead/lag damping; (2) providing a small, lightweight switchable damper for use in the rotor hubs of the invention; and (3) providing a method of preventing ground resonance conditions while minimizing loads and fatigue on aircraft components.
While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. | A damper has a piston having an axis, an outer surface, and opposing ends. Elastomeric seals are in sealing contact with the outer surface of the piston, the seals being coaxial with the piston and limiting movement of the piston to a path along the axis of the piston. The seals also define fluid chambers adjacent the ends of the piston. A primary passage communicates the fluid chambers, and a selectively switchable valve for controls a flow of fluid from one of the chambers to another of the chambers through the primary passage. When the flow of fluid through the primary passage is permitted, movement of the piston is resisted by a first spring rate due to a shear force required to cause shear deflection of the seals. When the flow of fluid through the primary passage is restricted, movement of the piston is resisted by a second spring rate due to a fluid force required to cause bulging deflection of the seals. | 1 |
BACKGROUND OF INVENTION
[0001] An embodiment relates to object sensor fusion.
[0002] Vision-imaging systems are used in vehicles for enhancing applications such as object detection systems and other vision/positioning systems. Such systems utilize a camera to capture the image and then extract objects from the image. Such objects may be other vehicles, pedestrians, or even objects within a road of travel.
[0003] Radar systems are also used to detect objects within the road of travel. Radar systems utilize radio waves to determine the range, altitude, direction, or speed of objects. A transmitter transmits pulses of radio waves which bounce off any object in their path. The pulses bounced off the object returns a tiny part of the wave's energy to a receiver which is typically located at the same location as the transmitter.
[0004] Detecting objects by cooperatively utilizing vision-imaging systems and radar systems would add confidence as to the detection and position of an object in the path of travel of a vehicle. Data associated or data correspondence between different modalities may be readily performed when the vehicle is traveling along a flat, non-pitched road; however, if the road of travel is not flat or the road pitch changes abruptly due to the structure of the road or due to harsh braking, then fusion of the data from complementary sensors of different modalities becomes increasingly difficult.
SUMMARY OF INVENTION
[0005] An advantage of an embodiment is the integral merging of data from two separate object detection systems which reduces offsets between the two object detections system so that the positions of each may be merged for providing greater confidence as to the objects' positions in the road of travel. The technique described herein offer robust and accurate association of data from the different modalities. The technique provides special handling targets leaving and entering the field-of-view of each modality such that assumptions may be made as to the correspondence between the respective targets within the captured field-of-views. Moreover, the data association technique described herein may be utilized as a subsystem to a fusion architecture technique that fuses data from different sensors through target tracking
[0006] An embodiment contemplates a method of associating targets from at least two object detection systems. An initial prior correspondence matrix is generated based on prior target data from a first object detection system and a second object detection system. Targets are identified in a first field-of-view of the first object detection system based on a current time step. Targets are identified in a second field-of-view of the second object detection system based on the current time step. The prior correspondence matrix is adjusted based on respective targets entering and leaving the respective fields-of-view. A posterior correspondence matrix is generated as a function of the adjusted prior correspondence matrix. A correspondence is identified in the posterior correspondence matrix between a respective target of the first object detection system and a respective target of the second object detection system.
BRIEF DESCRIPTION OF DRAWINGS
[0007] FIG. 1 is a schematic illustration of a vehicle equipped with object detection systems.
[0008] FIG. 2 is an exemplary image captured by a vehicle driven on a flat and straight road surface.
[0009] FIG. 3 is an exemplary image captured by a vehicle traveling along the curved and pitched road surface.
[0010] FIG. 4 is an exemplary target correspondence graph between a radar system and a vision system.
[0011] FIG. 5 is a block diagram illustrating the general concept of a target association technique.
[0012] FIG. 6 is a flowchart of a method for the recursive target association technique.
[0013] FIG. 7 is a block diagram of a fusion technique incorporating the recursive target association technique.
DETAILED DESCRIPTION
[0014] There is shown in FIG. 1 a vehicle 10 equipped with a first object detection system 12 and a second object detection system 14 . Each system utilizes a different type of sensor to detect objects. Each sensor within each respective system is able to detect and track multiple targets in its respective field-of-view. For the exemplary purposes herein, the first object detection system 12 includes a vision-based system and the second object detection system 14 includes a radar-based system. It should be understood that the respective systems are exemplary and that any two or more different object detection systems may be used.
[0015] A field-of-view for the vision system 12 is shown generally at 16 . A set of targets detected by the vision system 12 is identified as V 1 , V 2 , and V 3 . Each respective target identified by vision system 12 includes measurements such as longitudinal displacement, lateral displacement, longitudinal velocity, and lateral velocity.
[0016] A field-of-view of the radar system 14 is shown generally at 18 . A set of targets detected by the radar system 14 is identified as R 1 , R 2 , and R 3 . Each respective target identified by vision system 12 includes measurables such as longitudinal displacement, lateral displacement, longitudinal velocity, and lateral velocity.
[0017] The idea is to determine a correspondence between radar targets and vision targets in their common field-of-view. FIG. 1 shows an example of a correspondence between the radar targets and the vision targets V 1 →R 1 , V 2 →R 2 , and V 3 →R 3 . Since the measurables constantly change due to change of vehicle direction, speed, and occlusion with other vehicles, the respective targets must be tracked by each respective detection system at each instant of time.
[0018] Accurate association of data from different modalities is significant for target tracking, however, data association is a challenging task. Targets of vision systems in certain situations, such as a non-flat road surface, curvatures, and abrupt pitch angle changes of the host vehicle (e.g., caused by either the road or harsh braking) may result in a deviation from their true value significantly. Therefore, a distance between the vision targets may be significantly large. A commonly known technique for the corresponding problem is a technique known as the nearest neighbor matching. In the nearest neighbor matching, for every radar target, each radar target is assigned to a vision target having the nearest distance to it. The issue with the nearest matching method is that the decision is based only on current data.
[0019] The nearest neighbor matching method fails for scenarios shown in FIGS. 2-4 . FIG. 2 illustrates an image of a vehicle 17 driven on a flat and straight road surface 19 with no pitch changes at a time t 1 . Under such driving conditions, there is significant correspondence between the vision targets and radar targets in the time displaced images if the road of travel continued as a flat and straight road surface with no pitch changes.
[0020] FIG. 3 illustrates an image of the vehicle 17 traveling along the road of travel at a later time. As shown in the image, the road 19 includes pitch changes as well as curves. In addition to changes in the position of a vehicle captured within the image, the range to the target captured by the vision system becomes unpredictable. As shown in the graph illustrated in FIG. 4 , a significant distance between radar target measurements and vision target measurements are cause by the non-flat and curved road surface. The y-axis represents distance and the x-axis represents time. The tracking of targets by the vision system is represented by 20 and the tracking of the target by the radar system is represented by 22 . As shown in FIG. 4 , the correspondence of the target between the vision system and the radar system is significant at time t 1 . That is, the target as determined by the vision system and the radar system are measured at a substantially same longitudinal range. As time elapses, correspondence between the target tracked by the radar system and the vision system deteriorates and the correspondence becomes increasingly uncertain. This is the result of the road transitioning from a straight and flat road surface to a pitched and non-flat road surface. Correspondence of the target between the vision system and radar system gains confidence only after a time period elapses from t 2 (i.e., when the road of travel transitions to a consistent road surface). As shown in FIG. 4 , there is a lapse in association in targets from time period t 1 and t 2 .
[0021] The technique described herein overcomes the deficiencies of target association between radar systems and vision systems. To find a correspondence between radar targets and vision targets a Boolean matrix A of size M×N is maintained at each time step. M is the number of vision targets whereas N is the number of radar targets. The Boolean matrix A is updated at each step of time for re-determining which respective radar targets are associated with which respective vision targets. To identify a correspondence between a respective vision target V j and a respective radar target R k , a match between a respective vision target V j and a respective radar target R k is identified when a correspondence element a jk =1. It is assumed that each vision target only corresponds to at most one object. Therefore, for each N column in the Boolean matrix A, each column is summed and the largest summation is identified for a corresponding match between a respective vision target and a respective radar target. A formula for identifying whether there is a correspondence between a vision target and a radar target is represented as follows:
[0000]
∑
k
=
1
N
a
jk
=
{
1
0
(
1
)
[0000] where the sum is equal to 0 if V j is an outlier, and equal to 1 otherwise.
[0022] It is first assumed that there is a same set of targets in a sequence of captured images detected for the radar system and vision system. It is also assumed a tracker exists in each individual sensor. Based on target identity (i.e., the signal of a target identifier), historical matrices A(t−1), A(t−2), . . . , A(1), at time step t−1, t−2, . . . , 1, respectively, are known.
[0023] A rigid 2D transformation T is defined which is regarded as a transformation from a radar coordinate frame to the vision coordinate frame. [T(R k )] is defined as the radar target position at the vision coordinate frame. The radar targets (R 1 , R 2 , . . . , R N ) are modeled as Gaussian mixture model (GMM) distribution with parameters {R k |k=1, . . . , N} where R k represents the measurement of location of the radar (i.e., longitudinal and lateral displacement of targets). The formula for the GMM with parameters can be represented by the formula:
[0000]
p
(
v
)
=
∑
k
=
1
N
+
1
π
k
p
(
v
|
k
)
(
2
)
[0000] where p(v|k) is the 2D Gaussian distribution, i.e.,
[0000]
p
(
v
|
k
)
=
1
2
π
σ
2
exp
(
-
v
-
T
(
R
k
)
2
2
σ
2
)
for
k
=
1
,
…
,
N
(
3
)
[0000] where v is the random variable of a possible vision target location, and σ is a standard deviation.
[0024] In another embodiment p(v|k) is the 2D Gaussian distribution, i.e.,
[0000]
p
(
v
|
k
)
=
1
2
πσ
x
σ
y
exp
(
-
x
-
x
′
2
2
σ
x
2
-
y
-
y
′
2
2
σ
y
2
)
for
k
=
1
,
…
,
N
[0000] where v=(x,y) is the random variable of a vision target location; x and y longitudinal and lateral offsets of the vision target, respectively; x′ and y′ are longitudinal and lateral offsets of the k-th projected radar target T(R k ) in the vision system frame; and σ x and σ y are standard deviation in longitudinal and lateral directions, respectively. In this embodiment, several specific characteristics of vision system such as rough longitudinal measurement but accurate azimuth angle measurement can be modeled.
[0025] Given a vision target at range r, the standard deviation is set as σ x =αr and σ y =βr, respectively, where the constants α and β are determined by the performance specification of the vision system.
[0026] Next a component is modeled for noise or outliers as a uniform distribution which is represented by the formula:
[0000]
p
(
x
|
N
+
1
)
=
1
Γ
(
4
)
[0000] where Γ is the area of vision field-of-view. A coefficient for the GMM is represented by the formula:
[0000]
π
k
=
1
-
w
N
,
(
5
)
[0000] for k=1, . . . , N and π N+1 =w where w denote the probability of a target being an outlier. The vision targets (V 1 , V 2 , . . . , V M ) are viewed as independent and identically distributed samples of the GMM. The correspondence matrix can be treated as a Boolean random matrix. Each realization A represents the correspondences between radar and vision targets. This is verified as follows:
[0000] ā jk =E ( A jk )= p ( A jk =1). (6)
[0000] ā jk is the correspondence prior distribution which is usually set to be non-informative at time step 0 . This assumes that each vision target is assigned to every radar target at equal probability at time step 0 . This is represented by the formula:
[0000] ā jk =π k for all j. (7)
[0000] Given the prior ā jk , the posterior â jk , which is the resulting correspondence, can be computed. After the vision targets are observed V=(V 1 , V 2 , . . . , V M ) the posterior â jk is represented by the following formula:
[0000]
a
jk
=
p
(
A
jk
=
1
|
V
)
=
a
_
jk
·
p
(
V
j
|
k
)
∑
k
=
1
N
+
1
a
_
jk
·
p
(
V
j
|
k
)
,
for
j
=
1
,
…
,
M
,
k
=
1
,
…
,
N
(
8
)
[0000] wherein Â=[â jk ] is the posterior probability of matrix, p(V j |k) is the probability that the j-th vision target V j is associated with the k-th target R k , defined in Eq. (3), and 1/Σ k=1 N+1 ā jk ·p(V j |k) is the normalization factor to make p(A jk =1|V) a probability distribution.
[0027] As a result, the vision target V j is assigned to the k j −th radar target where k j =arg max k (â jk ). It should be noted that if k j =N+1, then the vision target is an outlier and is not assigned to any radar target.
[0028] FIG. 5 illustrates a block diagram illustrating the general concept of the target association technique. Detected radar target data 24 and vision target data 26 are input to a Bayesian framework model for data association inference at time t 1 . Also input to the Bayesian framework model 30 is the prior correspondence matrix (Ā) 28 determined at a last time period. A recursive data association technique is applied to the input data for generating a posterior correspondence matrix (Â) 32 . As a result, the posterior correspondence matrix (Â) 32 that is generated for the current time period is utilized as the prior correspondence at the next determination stage.
[0029] FIG. 6 illustrates flowchart of a method for the recursive target association technique. In step 40 , at time step zero, the prior correspondence matrix is initialized as a non-informative correspondence matrix. This treats all correspondence as equal at the initiation of routine since there are no pre-assumptions of any relationships between any vision targets and any radar targets. This is represented as ā jk =π k , for all j=1, . . . , M, and k=1, . . . , N+1.
[0030] In step 41 , a determination is made if a new frame of data has arrived from each of the sensing systems. A data frame includes data from both the radar system (R 1 , R 2 , . . . , R N ) and the vision system. (V 1 , V 2 , . . . , V M ). If the determination is made in step 41 that a new frame of data has not arrived, then the routine continues to check for the arrival of a new data frame from both the vision systems and the radar systems. If the determination is made in step 41 that new frame of data has arrived, then the routine proceeds to step 42 .
[0031] In steps 42 , the data frame is analyzed for determining whether a target leaves or enters the field-of-view of either the radar sensor or the vision sensor and adjusts the prior correspondence matrix Ā.
[0032] In step 43 , the data frame is analyzed for determining whether a respective vision target j showed up in the in current target list, but does not show up in the previous target list. If the respective vision target j showed up in the current target list, but is not showing up in the previous target list, then the respective row (i.e., respective vision target j) is initialized as non-informative. This is represented as ā j′k =π k for all k, where j′ is the new added row index.
[0033] In step 44 , the data frame is analyzed for determining whether a respective radar target k showed up in the previous target list, but does not show up in the current target list. If the respective radar target k showed up in the previous target list, but is not showing up in the current target list, then the respective column (i.e., respective radar target k) is removed from the prior correspondence matrix (Ā).
[0034] In step 45 , the data frame is analyzed for determining whether a respective vision target j showed up in the previous target list, but does not show up in the current target list. If the respective vision target j showed up in the previous target list, but is not showing up in the current target list, then the respective row (i.e., respective vision target j) is removed from the prior correspondence matrix (Ā)
[0035] In step 46 , the data frame is analyzed for determining whether a respective radar target k showed up in the in current target list, but does not show up in the previous target list. If the respective radar target k showed up in the current target list, but is not showing up in the previous target list, then a respective zero-value column is appended in the correspondence matrix (Ā).
[0036] In step 47 , the posterior matrix is computed. The posterior correspondence matrix (Â) is determined using the formula shown in eq. (8) for all j and k.
[0037] In step 48 , assignments relating to target correspondence are determined based on the posterior correspondence matrix (Â). That is, the column having the largest value closest to 1 is assigned the target correspondence between a respective radar target and a respective vision target (e.g.,
[0000]
∑
k
=
1
N
a
jk
[0000] is equal to 1 or 0).
[0038] In step 49 , the assignments of every vision target to a radar target are output. An index list (k 1 , k 2 , . . . , k m ) is outputted corresponding to vision targets (V 1 , V 2 , . . . , V m ). Each element in the index list represents the radar target index to which the vision target is assigned. The j-th vision target V j is assigned to the k j -th radar target and k j =arg max k (â jk ).
[0039] In step 50 , sensor registration is performed. Sensor registration includes removing error and bias of data from the different sets of sensors. This includes minimizing the target matching error between two sensors through estimating a 2D rigid transformation. The transformation between the two sensors is recursively estimated by using the prior value to derive updated value at every time step. This is performed by updating a 2D rigid transformation from T to where T is the past transformation and is the updated transformation. The rigid transformation is determined by the following formula:
[0000] T ′=(1−η) T+ηT*
[0000] where T* is the current estimate of the transformation based on the matching between the radar targets and vision targets and is computed by the formula
[0000]
T
*
=
arg
min
T
(
a
jk
V
j
-
T
(
R
k
)
2
2
σ
2
)
[0000] and the predefined small learning factor (η) is 0<η<1.
[0040] A solution for the transformation T* as shown above may be derived utilizing three parameters: t x , t y , ε, of the past transformation. Parameter t x represents the x-offset from the radar frame to the vision frame, parameter t y represents the y-offset from the radar frame to the vision frame, and ε represents the angular displacement offset from the radar frame to the vision frame. The transformation parameters are defined by the following two equations:
[0000]
x′=x−εy+t
x
[0000] y′=εx−y+t y .
[0000] The above formulas transform a point (x, y) to the new position (x′, y′).
[0041] It is assumed that V j =(x′ j , y′ j ) and R k =(x k , y k ). x′ j and y′ j are the longitudinal and lateral displacements of the j-th vision targets. x k and y k are longitudinal and lateral displacements of the k-th radar targets. T* can then be computed. T*=(t* x , t* y , ε*) and transformation parameters used to derive T* can be computed as follows:
[0000]
t
x
*
=
∑
j
,
k
a
j
,
k
(
x
j
′
+
∈
y
k
-
x
k
)
∑
j
,
k
a
j
,
k
,
t
y
*
=
∑
jk
a
jk
(
y
j
′
-
∈
x
k
-
y
k
)
∑
j
,
k
a
j
,
k
,
∈
*
=
∑
jk
a
jk
(
y
j
′
-
t
y
-
y
k
)
x
k
+
(
x
j
′
-
t
x
-
x
k
)
y
k
∑
j
,
k
a
j
,
k
[
x
k
2
+
y
k
2
]
,
[0000] wherein Â=[â jk ] is the posterior matrix, y′ j is a lateral displacement of the j-th vision target, ε angular displacement offset, y k is the lateral displacement of the k-th radar target, x′ j is the longitudinal displacement of the j-th vision target and x k is the longitudinal displacement of the k-th radar target.
[0042] In step 51 , the prior correspondence matrix at the next time step Ā t+1 =[ā jk ] is set to the posterior correspondence matrix at the current time step  t =[â jk ] where ā jk =â jk , for all j and k. That is, the computed posterior correspondence matrix at time step t is utilized as input as the prior correspondence matrix for computing the next posterior correspondence matrix for the next time step t+1.
[0043] A return is made to step 41 for awaiting a new frame of data and recursively updating the correspondence matrix.
[0044] FIG. 7 illustrates a block diagram of an alternative embodiment integrating the recursive target association technique into a target fusion algorithm.
[0045] In block 60 , a first object detection system (e.g., radar) senses for objects within the first object detection system's field-of-view. Similarly, in block 61 , a second object detection system (e.g., vision) senses for objects within the second object detection system's field-of-view.
[0046] In block 62 , targets are identified within the first object detection system's field-of-view. For example, the targets relate to objects captured by the radar detection system.
[0047] In block 63 , targets are identified within the second object detection system's field-of-view. For example, the targets relate to objects captured by the vision detection system.
[0048] Both the radar targets 62 and the vision targets 63 are regarded as independent and identical distribution samples.
[0049] The data association technique may be used to associate targets from the radar detection system and vision detection system directly as described in FIG. 6 . However, the integration technique as described herein utilizes a third variable for integration with the radar target respectively, and utilizes the third variable for integration with the vision target respectively. Thereafter, the results from both integrations are fused.
[0050] In block 64 , the feedback data as it relates to fused targets from a motion model is utilized as inputs for data association technique with radar targets, respectively, and with vision targets, respectively. The feedback data from the target motion model is identified as a predicted fusion target based on its last known position and motion analysis. Details of the predicted fusion target will be discussed in detail later.
[0051] In block 65 , detected radar targets 62 and the predicted fusion targets 64 are provided as inputs to a first data association module that utilizes the recursive target association technique. Data association as described in FIG. 6 is applied on the radar targets 62 and the predicted fusion targets 64 for generating a first posterior correspondence matrix.
[0052] In block 66 , detected vision targets 63 and the predicted fusion targets 64 are provided as inputs to a second data association module that utilizes the recursive target association technique. Data association as described in FIG. 6 is applied on the vision targets 63 and the predicted fusion targets 64 for generating a second posterior correspondence matrix.
[0053] In block 67 , the outputs from the recursive target association technique in block 65 and the outputs from the recursive target association technique 66 is provided to a fusion system that utilizes a target tracking using sensor fusion. The fusion system fuses data from each posterior correspondence matrix for estimating the location of a given target. A fusion technique that can be used in block 67 is described in U.S. Pat. No. 7,460,951 having an issue date of Dec. 2, 2008, which is herein incorporated by reference in its entirety.
[0054] In block 68 , the fusion targets are identified from the output of the fusion system in block 67 . The fusion targets are modeled as a Gaussian mixture model (GMM) distribution.
[0055] In block 69 , a delay is applied to the fusion target data prior to proceeding to block 70 .
[0056] In block 70 , a target motion model is applied to the fusion targets. The target motion model utilizes the fusion target data and predicts a future position of the targets based on the last known position and a trajectory of the target. Motion tracking involves locking onto a target and following the object through multiple frames and predicting a path of the target based on the trajectory of the target. In each fusion target, a longitudinal offset (x), a lateral offset (y), a longitudinal speed (v_x), and a lateral speed (v_y) of the target are estimated state variables. Therefore, if the current state of the target is known, then the future state variables at time dT late may be estimated using the following formulas:
[0000]
x′=x+dTv
—
x
[0000]
y′=y+dTv
—
y
[0000]
v
—
x′=v
—
x
[0000]
v
—
y′=v
—
y
[0000] Therefore, the target motion model transforms a target's current state to its future state s′ as represented by the following formula:
[0000] s′=F ( s )+ w
[0000] where w is a random variable of appropriate dimension, typically with a zero mean and a covariance matrix Q.
[0057] After a target motion model of the target is generated, a predicted position of the target is determined in block 64 and is used as an input to the data association techniques in blocks 65 and 66 .
[0058] While certain embodiments of the present invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention as defined by the following claims. | A method of associating targets from at least two object detection systems. An initial prior correspondence matrix is generated based on prior target data from a first object detection system and a second object detection system. Targets are identified in a first field-of-view of the first object detection system based on a current time step. Targets are identified in a second field-of-view of the second object detection system based on the current time step. The prior correspondence matrix is adjusted based on respective targets entering and leaving the respective fields-of-view. A posterior correspondence matrix is generated as a function of the adjusted prior correspondence matrix. A correspondence is identified in the posterior correspondence matrix between a respective target of the first object detection system and a respective target of the second object detection system. | 6 |
FIELD OF INVENTION
[0001] The present invention relates to the development of a biosensor to determine potassium in human blood serum using dibenzo-18-crown-6 (DB18C6) as ionophore. This invention also reports the fabrication and characterization of ISFET (ion-sensitive field-effect transistor) coated with a monolayer of crown ether on the gate of the electrode. D18C6 dissolves in chloroform and tends to form a monolayer on the surface of working electrode. Human blood serum contains potassium in ppm levels i.e. 137 to 200 mg/litre and sodium co-exists with a 30 times higher concentration. Such a high concentration tends to interfere the selectivity of potassium but D18C6 proves to have an excellent selectivity towards potassium and is highly sensitive to the lowest concentration of potassium levels present in the human blood serum.
[0002] Total absence or very low chemical interaction between materials constituting a sensor and a biological sample of human electrolytes is very important in both, chronic illness and in acute menacing conditions. Potentiometric methods based on ion-selective electrodes serve this purpose far better than optical methods in clinical laboratories. This potentiometric based potassium biosensor is easy to prepare, assemble, economically viable. It could be used in the disposable mode if it is made in the form of strip that has the dimensions of the ISFET gate. The chances to marketability are very high as the preparative method does not involve complicated procedure and is economically very promising because each fresh monolayer requires less than 500 microgram of the crown ether. The response time of ionophore was within a minute and the shelf life of the electrode either on use or idle, was found to be a three months period. The electrode surface can be re-coated and used.
BACKGROUND AND PRIOR ART OF THE INVENTION
[0003] Potassium monitoring in whole blood is one of the most important routine analysis performed in clinical laboratory, it is of fundamental importance both for the early detection of post-operative shock and for heart surgery. Determination of potassium contents of serum, urine, and foods is also very important in clinical and medical fields, since the potassium contents are related to renal diseases. These diseases restrict patients to a diet containing a large amount of potassium. From the potassium determination, medical information concerning physical conditions of the patient can be obtained. In the case of hypopotassemia, alkalosis, cirrhosis of liver, diuretic drugs, etc. are suspected. On the other hand, when potassium concentration in human serum becomes higher than 9 mmol dm −3 , heart often stops.
[0004] Biological active-transport systems involving ions, in particular K + , have important functions in the organism, which are essential for regulation of many intracellular activities. These systems are related in the transmission of information by the nervous system and in the excitation and relaxation cycle of muscle tissue. Principally, accurate, easy and rapid sensing of potassium ions in human blood serum is very important prior to cardiac surgery to assess the condition of the patient.
[0005] Crown ethers have been reported to be an inexpensive neutral carrier in the construction of Ion Selective Field Effect Transistors. Additionally, these carriers have the option of covalently attaching the desired molecule for electro analytical applications. The characteristic of crown ether is their selective complexation ability. They bind the cationic portion of alkali and alkaline earth metal salts (guest) in to the cavity of the crown ring (host). The selectivity is dependent principally on the relative size of the cavity of the crown ring and the diameter of the cation, number of donor atoms in the crown ring and the topological effect and the relationship between the hardness of the cation and that of the donor atom, and charge number of the cation. In the case of crown complexes, a metal cation-anion contact always occurs from the open faces of the ring plane. Dibenzo-18-crown-6 used here was shown to have a circular cavity of diameter 2.6-3.2 A° which fits the exact size of potassium ion of 2.66 A° and makes it an excellent choice to be a sensing material for potassium ions.
[0006] Potentiometry using ion selective electrodes (ISE) is the method of choice due to the easy and fast performance of the assay. About 200 million clinical assays of potassium every year are performed using ISEs in the USA. It is well-known that ion selective electrodes are based on the use of a water-insoluble membrane that can be considered as a water-immiscible liquid of high viscosity, containing an ionophore which binds selectively the ion of interest and it generates a membrane potential. Potentiometric detection based on ion-selective electrodes, as a simple method, offers several advantages such as speed and ease of preparation and procedures, simple instrumentation, relatively fast response, wide dynamic range, reasonable selectivity and low cost. Besides, they are ideally suitable for on-site analysis and, nowadays, were found to be applicable in the analysis of some biologically relevant ions, process control and environmental analysis. Miniaturization of the system is realized using silicon technology. The potassium concentration is measured potentiometrically using ISFET coated with crown ether in combination with an Ag/AgCl reference electrode integrated on the same chip. To overcome problems resulting from a long time contact of the sensor with protein-containing sample solution, an automated measuring protocol was applied where the sensor is brought in contact with the sample only for short time segments. Immediately after the stabilization of the measuring signal the chip is flushed with a commercial Ringer solution of constant potassium concentration. The frequency of sample/conditioning solution cycles depend on the diagnostic demand. In this way the active sensing area of the sensor is cleaned time to time from the sample. Furthermore, the sensor signal in the cleaning solution serves as a calibration point.
[0007] Potentiometric ion sensors based on ion-sensitive field-effect transistors (ISFETs) are attracting increasing attention primarily because of their small size, robustness, low cost, fast response time and low output impedance. For the ISFET, the metal connection of the reference electrode acts as a remote gate. The equation giving the dependence of threshold voltage on the pH of the solution in contact with the gate is,
v Th(ISFET) − E ref −Φ si −ψ+χ−Q f /C d +2|φ p |+1/C d √2ε o ε s qN A (2|Ψ p |) (1)
where E ref is the constant reference electrode potential Φ si is the silicon work function, χ is surface dipole potential of the solvent and Ψ is the interfacial electrostatic potential at the solution/dielectric interface whose sensitivity to changes in bulk pH is expressed by the equation,
∂Ψ/∂ p H =−2.303( RT/F )α (2)
R is universal gas constant, T is absolute temperature, F is Faraday's constant and α is a dimensionless sensitivity parameter (0<α<1), given by,
α=1/(2.303 KTC/q 2 β)+1 (3)
k is Boltzmann constant, T is temperature in Kelvin scale, C is the differential double layer capacitance at the insulator-electrolyte interface, q is electronic charge and β is surface proton buffer capacity determining the ability of the gate dielectric surface to absorb or release protons.
[0008] But the silicon dioxide-silicon nitride gate ISFET shows sensitivity to various ions in aqueous solution such as H + , Na + , K + , Ca + , Zn ++ , Fe ++ , etc., besides H + -ion. Extension of ISFETs for measuring species other than hydrogen ions is a vital research area. ISFETs with ion-sensitivity and selectivity to different ionic species can be fabricated by depositing polymeric membranes containing specific receptor molecules on the gate surface.
[0009] Reference to be made to a publication by Shoji Motomizu et al, Analyst, 1988, 113, 743-746 wherein potassium in river water was determined by a spectrophotometric method involving flow injection coupled with solvent extraction. Dibenzo-18-crown-6 was used along with the dichloro derivative of ethyl orange. The procedure was shown to have less interference from foreign ions and the sensitive up to a potassium ion concentration of 10 −5 M. The main problem is that dye employed in this study was dissolved in lithium hydroxide and hence the pH of the reagent solution was 10 which were unsuitable to determine potassium ions in blood serum.
[0010] Reference may be made to a publication by E. Malavolti et al, Analytica Chimica Acta 1999, 401, 129-136 wherein an optrode for continuous monitoring of potassium in whole blood was realized using valinomycin as ionophore and a neutral chromoionophore whose absorbance depends on the pH of the local environment. Membrane preparation was complicated and involves the following chemicals: chromoionophore, tetrahydrofuran, valinomycin, potassium tetrakis(4-chlorophenyl)borate, bis(2-ethylhexyl) sebacate and PVC. The main drawback of this protocol is that the sensor is sensitive to pH and maintenance of the thickness of the membrane. Otherwise, as the potassium concentration changes, all the components in the membrane bulk would shift to the new equilibrium so that there will be a change in the signal.
[0011] Reference may be made to a publication by P. C Pandey and R. Prakash, Sensors and Actuators 1998, B 46, 61-65 wherein a potassium ion-selective electrode using PVC matrix membrane impregnated with dibenzo-18-crown-6 at the surface of the polyindole modified electrode is reported. The lowest detection limit for the potassium ion sensor is 7.0×10 −6 mol dm −3 . The inherent disadvantages of this work are that preparation of sensor electrode requires tedious and complicated procedure and the selectivity of potassium ion over other cations in the same solution or human blood serum is not reported. The lowest detection limit was higher than the concentration of potassium in blood serum.
[0012] Reference may be made to a publication by Albrecht Uhlig et al, Sensors and Actuators B, 1996, 34, 252-257 wherein a miniaturised ion-selective sensor chip for potassium measurement in vivo for whole blood. Here, Valinomycin was used as ionophore and the potassium concentration is measured potentiometrically using an ion selective polymer membrane in combination with an Ag/AgCl/p-HEMA reference electrode integrated on the same chip. The main problem is the clotting of blood that has to be prevented by addition of an external reagent and unacceptable drift, which might be due to the solid state internal contact, loss of membrane ingredients and water absorption.
[0013] Reference may be made to a publication by Johan Bobaka et al, Analytica Chimica Acta, 1999, 385, 195-202 wherein all-solid-state potentiometric potassium-selective electrodes with plasticizer-free membranes were prepared by incorporation of valinomycin as the ionophore and potassium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate as the lipophilic additive in a semiconducting conjugated polymer matrix of poly(3-octylthiophene). The membrane components were dissolved in chloroform and deposited on glassy carbon by solution casting. The main bottleneck is the sub-Nernstian response, the degradation of the response with time, especially for thin membranes and the observation of a relatively large ion transfer resistance at the membrane/solution interface.
[0014] Reference to be made to a publication by Carlos Alexandre Borges Garcia et al, Journal of Pharmaceutical and Biomedical Analysis 2003, 31, 11-18 wherein a simple and rapid method was developed for the K+ions determination employing a flow injection system using a flow-through electrode based on the naturally-occurring antibiotic ionophore nonactin occluded in a polymeric membrane. The nonactin ionophore was trapped in poly (ethylene-co-vinyl acetate) (EVA) matrix (40% w/w in vinyl acetate) and dispersed on the surface of a graphite-epoxy tubular electrode. The plasticizer-free all-solid-state potassium-selective electrode showed a linear response for K + ion concentrations between 5.0×10 −5 and 5.0×/10 −2 M with a near-Nernstian slope of 51.5 mV per decade, when Tris-HCl buffer (pH 7.0;0,1 M) was employed as a carrier. The major setback is the maintenance of neutral pH in samples with ammonium ion as analytically interfering ion and sensing range of K + ion concentration was well above the blood serum range.
[0015] Reference to be made to a publication by N. Abramova et al, Talanta, 2000, 52, 533-538 wherein application of a potassium ion sensor based on an ion sensitive field effect transistor (ISFET) for ion control of a dialysis solution in an artificial kidney and in blood plasma of patients treated by hemodialysis is presented. Commercial potassium ionophore valinomycin is used. The studied ISFETs have the required stability and sensitivity to monitor the potassium ion concentration in dialysis solutions within the artificial kidney apparatus. The major drawback is that ISFETs have not been tried on real blood samples.
[0016] Reference to be made to a publication by Daniela P. A. Correia et al, Talanta, 2005, 67, 773-782 wherein an array of potentiometric sensors for simultaneous analysis of urea and potassium in blood serum samples were developed. Urea biosensors based on urease immobilized by crosslinking with BSA and glutaraldehyde coupled to ammonium ion-selective electrodes were included in arrays together with potassium, sodium and ammonium PVC membrane ion-selective electrodes. Coupling of biosensors with ion-selective electrodes in arrays of sensors raises a few problems related to the limited stability of response and unidirectional cross-talk of the biosensors, and this matter was also subjected to investigation in this work. Up to three identical urea biosensors were included in the arrays, and the data analysis procedure allowed the assessment of the relative performance of the sensors. The major disadvantage is lack of identical cross-talk between urea sensors with other biosensors. This arises mainly due to the irregular enzymatic layer in some biosensors as a consequence of the procedure used for enzyme immobilization.
OBJECTS OF THE INVENTION
[0017] The main object of the present invention is to develop a biosensor to determine potassium in human blood serum. Dibenzo-18-Crown-6 (DB18C6) is proven to be the ideal ionophore. ISFET (Ion sensitive field effect transistor) made of dual dielectric SiO 2 —Si 3 N 4 gate has a channel length L=12 microns and channel width W=4800 microns is used as the working electrode. D18C6 ionophore is deposited on the gate of ISFET. Calibrations in standard KCl solutions showed that the sensitivity of Crown Ether-ISFET towards potassium was double that of the nitride gate-ISFET. The same observation was noted for blood serum samples.
[0018] Another object of the present invention is the investigation of cross-sensitivity of sodium ions in presence of standard KCl solutions.
[0019] Still another object of the present invention is the investigation of cross-sensitivity of sodium ions in diluted human blood serum samples.
[0020] An object of the present invention, is to study the sensitivities of ISFET with/without the crown ether layer on the gate towards potassium and sodium ions in various concentration ranges Potassium: 100-400 mg/L; Sosium:200:1000 mg/dl.
[0021] Another object of the present invention is to study the ISFET response characteristics (a) without and (b) with crown ether layer on the gate; by carrying out standardization measurements out in standard KCl solutions with concentrations in human blood serum range ( FIG. 3 ).
[0022] Still another object of the present invention is to study the sensitivity of the ISFET with and without crown ether on the gate towards sodium ion was found to be comparatively less than that of crown ISFET for potassium, ensuring that sodium in blood serum did not interfere with the measurements. ( FIG. 10 )
SUMMARY OF INVENTION
[0023] Accordingly the present invention deals with the development of biosensor to direct potentiometric determination of total potassium concentration in human blood serum. The biosensor developed consists of Dibenzo-18-crown-6 as ionophore and ISFET (Ion-sensitive field effect transistor) as substrate with in-built Ag/AgCl reference electrode. Normally, the silicon dioxide-silicon nitride gate ISFET shows sensitivity to various ions in aqueous solution such as H + , Na + , K + , Ca + , Zn ++ , Fe ++ , etc., besides H + -ion. Extension of ISFETs for measuring species other than hydrogen ions is a vital research area. ISFETs with ion-sensitivity and selectivity to different ionic species can be fabricated by depositing polymeric membranes containing specific receptor molecules on the gate surface. Earlier works employing the anthryl azacrown structures (crown- 5 , crown- 6 ) have been shown to be sensitive to sodium and potassium cations among others, although the selectivity for these ions over other alkali metal ions is only modest. Hence to identify an ionophore such as dibenzo-18-crown-6 that specifically selects potassium in presence of other cations in the human blood serum is an important and interesting discovery. The blood serum electrolyte content is as follows: Cl (97-107 mM), Na (132-144 mM), K (3.6-4.8 mM), Ca (2.0-2.7 mM), Mg (0.7-1.2 mM), Al (17-32.6 μM), Br (0.09 μM), Cu (12-22.5 μM), F (5.3-23.7 μM), I (0.4-0.7 μM), Fe (5.7-31.7 μM), Pb (0.1-0.4 μM), Mn (1.5-3.5 μM), Sn (0.3-8 μM), Zn (0.9-3.7 μM). The highlight of this invention is the ability of crown ether ionophore to select potassium and sense accurately even in low concentration range of blood serum. Most interestingly, this ionophore is specifically selective to potassium even in the presence of 36% higher sodium concentration. The performance of the biosensor is validated as it obeys Nernst law and gives a slope value of 59.2 mV/decade for the plot of potential vs. concentration.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 Binding of the potassium ion within the crown ether molecular structure.
[0025] FIG. 2 Schematic cross-section of potassium ISFET.
[0026] FIG. 3 . ISFET response characteristics (a) without and (b) with crown ether layer on the gate; measurements have been carried out in standard KCl solutions with concentrations in human blood serum range.
[0027] FIG. 4 Plots of the potentials relative to logarithm of potassium ion concentration obtained from ISFET characteristics.
[0028] FIG. 5 Study of pH distribution of blood serum samples.
[0029] FIG. 6 ISFET response characteristics at very low KCl concentrations (a) without and (b) with crown ether layer on the gate.
[0030] FIG. 7 Semi-logarithmic plots for the ISFET characteristics.
[0031] FIG. 8 Distribution of ISFET potential with number of patients.
[0032] FIG. 9 Distribution of potassium ion concentration with number of patients.
[0033] FIG. 10 Plots of potential versus NaCl concentration for ISFETs without and with crown ether layer on the gate.
DETAILED DESCRIPTION OF INVENTION
[0034] Accordingly, the present invention provides an improved and advanced version of the biosensor to determine the low concentration range of Potassium (3.6-4.8 mM or 151.22-205.4 mg/litre)) in human blood serum. The components of the biosensor as shown in FIG. 2 and described herein are as follows:
1: P-substrate: The starting material on which the ISFET is fabricated. Here P-type Czochralski silicon wafer of resistivity 15-20 ohm-cm (7.4×10 14 cm −3 ) and orientation <100> has been used. 2, 3: N + source and drain regions: Heavily phosphorous diffused regions in P-substrate. The source is so named because it is the source of the charge carriers (electrons for N-channel, holes for P-channel) that flow through the channel; similarly, the drain is where the charge carriers leave the channel. 4, 5: Terminal connections for source and drain: These are wires or leads for taking connections from source and drain regions of the ISFET. 6: Substrate connection which is grounded: Wire or lead from the P-substrate that is kept at ground potential during ISFET operation. 7: Field oxide: Thick oxide layer in a MOS device. It is formed to passivate and protect semiconductor surface outside of active device area. Actually, it is a part of ISFET but does not participate in device operation 8: SiO 2 +Si 3 N 4 gate dielectric: An insulator made of two layers, silicon dioxide and silicon nitride, used between the gate and substrate of ISFET. 9: Crown ether layer: Potassium-ion selective layer applied on the gate.
[0042] Components 1 to 8 comprise the ISFET. Component 9, the crown ether coating on the gate, provides selectivity to the sensor for potassium ions. On trapping K + ions by the crown ether layer, the gate-source potential increases. The change in gate-source potential as a function of potassium ion concentration gives the calibration characteristic of the sensor.
[0043] As the blood serum samples had a narrow spread of pH range, influence of pH variations on the measurements is insignificant. Cross-sensitivity of crown ether ISFET towards sodium ions has also been investigated and found to have negligible effect. As the sensing material or ionophore, dibenzo-18-crown-6 is readily amenable to chemical modification as it attaches potassium via ion-pair formation and exhibits selective host-guest chemistry. The response time of biosensor is 30-60 seconds and the ionophore is stable for a cycle life of one week. The shelf life is robust and can be idle even for months and reactivated by immersing in a diluted solution of KCl. The most important requirements of an ion sensor are fulfilled by our biosensor as follows: (1) Small −5 ml of sample volume, 12/4800μ dimensions (ISFET) required for guaranteed analysis; (2) High selectivity in presence of other ions that may be found in biological samples; (3) High linearity of sensors response in a blood serum concentration range.
[0044] In an embodiment of present invention, a device for measuring the concentration of ions in human blood serum characterized in having a coating of dibenzo-18-crown-6 dissolved in chloroform.
[0045] In another embodiment of present invention, dibenzo-18-crown-6 is used as ionophore to enable the specific selectivity of potassium in blood serum.
[0046] In yet another embodiment of present invention, dibenzo-18-crown-6 acts as host with 2.6-3.2 A° cavity size which fits the exact size of potassium ion of 2.66 A° (guest) and makes it an excellent choice to be a sensing material for potassium ions( FIG. 1 ).
[0047] In another embodiment of present invention, the amount of crown and chloroform used for the coating was 200-500 mg and 0.25-0.75 ml respectively.
[0048] In yet another embodiment of present invention, crown ether has been deposited on the ISFET gate by dissolving the crown ether in chloroform and placing a drop over the ISFET gate.
[0049] In still another embodiment of present invention, each 1 ml of human blood serum was diluted to 50 times.
[0050] In an embodiment of present invention, the effect of pH in blood serum samples was proved to be nil. These diluted samples showed a constant pH ˜7.0-7.1, confirming the maintenance of pH within close tolerance by the human body; therefore any errors due to pH variation amongst the samples were eliminated ( FIG. 5 ).
[0051] In another embodiment of present invention, ISFET response characteristics at very low KCl concentrations (blood serum range) (a) without and (b) with crown ether layer on the gate and the derived plots show the gate with crown ether fare 2.16 times higher sensitive than the gate without crown ether ( FIGS. 6 and 7 ).
[0052] In yet another embodiment of present invention, blood serum (fresh or stored) samples were tested for potassium concentration using ISFET-crown ether gate and the out potential was recorded. ( FIG. 8 )
[0053] In another embodiment of the present invention, chloroform is used for dissolving dibenzo-18-crown-6.
[0054] The invention is described in detail with reference to the examples given below which are provided to illustrate the invention and therefore, should not be construed to limit the scope of the invention.
EXAMPLE 1
Fabrication and Package of ISFET Device
[0055] The device has been fabricated on P-type Czochralski silicon wafers of resistivity 15-20 ohm-cm (7.4×10 14 cm −3 ) and orientation < 100 >. Fabrication technology of the ISFET, based on the NMOSFET technology comprised the following processing steps: (i) Field oxidation (1100° C., 30 min. dry O 2 +120 min. wet O 2 +30 min. dry O 2 ) giving oxide thickness=0.9 μm. (ii) First photolithography for source/drain N + diffusion, and oxide etching. (iii) Phosphorous diffusion (1050° C., 30 min.): Sheet resistance<3 ohms/square cm. (iv) Second photolithography for gate window, and oxide etching. (v) Gate oxidation (trichloroethylene ambient), 1000° C., 120 min., dry O 2 , oxygen flow rate 2 litre/min, a little TCE vapour was carried down the tube by a slow bleed of N 2 through TCE bubbler at 25° C., t ox =140 nm. (vi) Nitridation (LPCVD), 780° C., 25 min, initial pressure=0.02 torr, deposition pressure of dichlorosilane and ammonia gas mixture=0.2 torr, dichlorosilane=20 cc, ammonia 200 cc, gas ratio=1:10, t Nitride =100 nm; annealed at 900° C. for 30 min in N 2 . (vii) Third photolithography for contact holes, and oxide etching. (viii) Sputtering of chromium (50 nm) and gold (500 nm). (ix) Fourth photolithography for metal pattern delineation, and metal etching. (x) Metal sintering, (xi) Wafer scribing, and chip sorting and mounting on ceramic substrate. (xii) Wire bonding. (xiii) Protecting the metal pads and wires by insulating epoxy (Epotek H 70E/H74, cured at 120° C., 30 min.) with soldering pads protected by RTV compound. The gate region has been left exposed.
EXAMPLE 2
Deposition of Crown Ether on the Gate Region of ISFET
[0056] Crown ether has been deposited on the ISFET gate by dissolving the crown ether in few drops of chloroform to form a paste. Usually, few micrograms of the ionophore were sufficient to coat the gate ISFET.
EXAMPLE 3
Optimization of Coating on Gate
[0057] 200 mg of crown dissolved in chloroform solvent forms a monolayer of the coating on the surface of the gate. On exposure to air at room temperature, chloroform evaporates at once and leaves behind the ionophore.
EXAMPLE 4
Measurement Procedure
[0058] Measurements have been carried out using an in-house assembled signal conditioning circuit for direct reading of pH. An Ag/AgCl reference electrode has been used. This circuit gives an output voltage equal to the pH of the solution in which the ISFET is immersed. The circuit including the ISFET has an overall voltage gain of 20. The measurements have been performed before and after crown ether layer deposition.
[0059] Device operation: On trapping K + ions by the crown ether layer, the gate-source potential increases. The change in gate-source potential as a function of potassium ion concentration gives the calibration characteristic of the sensor.
[0060] The following steps are involved in measuring the potassium ion concentration:
a) dipping the ISFET gate in the serum
ISFET was dipped in 50 ml of standard solutions and serum for measuring the potential.
b) reading the potential
Potential was read for each standard and serum sample. Standard plot—potential difference/concentration was drawn for standard samples.
c) matching the read potential with that of the standard values: Potassium concentration in the serum sample was obtained from the standard graph
EXAMPLE 5
Characterization and Standardization and Calibration of ISFET
[0066] Characterization of ISFET was done with respect to KCl concentration from 100 to 400 mg/litre which is in the range of interest for the human blood serum analysis. Standardization of ISFET with KCl solutions with and without crown ether was studied. ( FIG. 3 ).The blood serum samples were prepared for measurement with ISFET by diluting 1 ml each of human blood serum samples to 50 ml because the 1 ml solution was insufficient for dipping ISFET along with the reference electrode.
[0067] The measurement of potentials related to potassium ion concentration in different blood serum samples were done with and without crown ether on the ISFET gate.
[0068] The ISFET calibration using atomic absorption spectroscopy for standard KCl solutions and diluted human blood serum samples.
[0000] Advantages:
[0069] The biosensor can detect potassium ions in human blood serum with high specificity even in 50 times diluted blood.
[0070] The sensitivity and specificity of the biosensor is due to coating of Crown ether, Di benzo 18-crown 6-ether over the dual dielectric silicon dioxide Silicon nitride gate.
[0071] It is easy to prepare, assemble and economically viable.
[0072] The Db 18 C6 ionophore could be used in the disposable mode if it is made in the form of strip that has the dimensions of the ISFET gate.
[0073] The preparative method does not involve complicated procedure and is economically very promising because each fresh monolayer requires less than 500 microgram of the crown ether.
[0074] The response time of ionophore was within a minute.
[0075] The shelf life of the electrode either on use or idle, was found to be a three months period.
[0076] The electrode surface can be re-coated and used. | The present invention relates to the development of a biosensor to determine potassium in human blood serum using dibenzo-18-crown-6 (DB18C6) as ionophore. Human blood serum contains potassium in ppm levels i.e. 137 to 200 mg/litre and sodium co exists with a 30 times higher concentration. Such a high concentration tends to interfere the selectivity towards potassium, but DB18C6 proves to have an excellent selectivity towards potassium and is highly sensitive to the lowest concentration of potassium levels present in the human blood serum. So the present invention reports the fabrication and characterization of ISFET (Ion Selective Field Effect transistor) coated with a monolayer of crown ether, dissolved in chloroform, on the gate of electrode. | 6 |
This application is a continuation of application Ser. No. 09/227,054 filed Jan. 7, 1999, abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a rotation angle sensor, a torque sensor incorporating the rotation angle sensor, and an electrically driven power steering apparatus using the torque sensor, and, more particularly, to a rotation angle sensor which can detect rotational angles with high precision, and apparatuses to which the rotation angle sensor is applied.
2. Description of the Related Art
FIG. 12 illustrates a conventional rotation angle sensor, wherein a rotary drum 2 , having disk-shaped magnetic portions, is affixed to a rotary shaft 1 . A magnetic code, consisting of a plurality of magnetic north-south (N-S) poles, is formed along the entire outer periphery of the rotary drum 2 .
A magnetic detecting sensor 4 is provided so as to be spaced from the outer periphery of the magnetic drum 2 by a predetermined gap P that is disposed therebetween, whereby the conventional rotation angle sensor is formed.
Such a conventional rotation angle sensor is constructed such that when the magnetic drum 2 is rotated as a result of rotation of the rotary shaft 1 , the magnetic sensor 4 detects analog changes, that is changes in the magnetic forces of the magnetic poles, in order to detect the angle of rotation of the magnetic drum 2 .
A description will now be given of a conventional torque sensor, wherein two such rotation angle sensors described above are mounted to a rotary shaft 1 having a drive shaft portion la and a load shaft portion 1 b illustrated in FIG. 13 .
The drive shaft portion 1 a and the load shaft portion 1 b of the rotary shaft are connected together by a resilient member (not shown), being a torsion bar.
The two rotary drums 2 and 3 are affixed to the drive shaft portion 1 a and the load shaft portion 1 b , respectively. They are connected towards an end of the drive shaft portion 1 a and an end of the load shaft portion 1 b that is connected to the drive shaft portion 1 a , and are separated by a distance L.
A pair of magnetic sensors 4 and 5 are provided such that the magnetic sensor 4 is separated from the outer periphery of the rotary drum 2 by a predetermined gap P 1 and the magnetic sensor 5 is separated from the outer periphery of the rotary drum 3 by a predetermined gap P 2 .
In such an operating shaft 1 , by applying a torque to the drive shaft portion 1 a that is greater than the torque applied to the load shaft portion 1 b , the drive shaft portion 1 a and the load shaft portion 1 b can be rotated.
When the rotary shaft 1 is rotated, the load shaft portion 1 b starts to rotate slightly later than the drive shaft portion 1 a , due to the resilient member.
A slightly delayed rotation of the load shaft portion 1 b results in a difference between the rotational angle of the drive shaft portion 1 a and that of the load shaft portion 1 b . The difference in the rotational angles is proportional to the rotational torque on the drive shaft portion 1 a , so that when the difference in the rotational angles is large, the rotational torque on the drive shaft portion 1 a is large, whereas when the difference in the rotational angles is small, the rotational torque on the drive shaft portion 1 a is small.
Such a conventional torque sensor can detect the rotational torque on the drive shaft portion 1 a by computing the difference between the rotational angles of the drive shaft portion 1 a and the load shaft portion 1 b through an integrated circuit (IC), which is not shown.
However, in such a conventional rotation angle sensor and torque sensor, rotational drums, being magnetic media, are directly mounted to the rotary shaft 1 , so that when a large load torque is applied to the load shaft portion 1 b , the drive shaft portion 1 a and the load shaft portion 1 b may become decentered. When decentering occurs, the amount of gap P 1 between the rotary drum 2 and the magnetic detecting sensor 4 and the amount of gap P 2 between the rotary drum 3 and the magnetic detecting sensor 5 change, so that the magnetic detecting sensors 4 and 5 cannot detect the strength of the magnetic field between the two rotary drums 2 and 3 with precision. This makes it difficult to make precise detections of the difference between the rotational angles.
Therefore, when such a conventional torque sensor is used in an electrically driven power steering apparatus of, for example, an automobile, the shafts 1 a and 1 b must be formed precisely and made highly durable, in order for the power steering apparatus to provide highly reliable power steering properties.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to make it possible to overcome the above-described problems in order to provide a high-precision angle sensor.
To this end, according to a first aspect of the present invention, there is provided a rotation angle sensor comprising a rotary member having a gear portion at the outer peripheral portion thereof, the rotary member having a shaft-inserting hole at the center of rotation thereof; a code plate which engages the gear portion of the rotary member, the code plate having an information recording portion which rotates in response to the rotation of the rotary member; and a detecting element for detecting information written on the information recording portion; wherein when the code plate rotates as a result of rotation of the rotary member, the detecting element detects the information on the code plate in order to detect the rotation angle of the rotary member.
Although not exclusive, in a preferred form of the invention, the rotary member may comprise a first rotary member portion and a second rotary member portion, the first rotary member portion and the second rotary member portion being separately rotatable and having the same center of rotation; the code plate may comprise a first code plate portion and a second code plate portion, each having a gear portion which engages the rotary member and being separately rotatable; and the detecting element may comprise a first detecting element portion and a second element portion for detecting information on the first code plate portion and the second code plate portion, respectively. In this structure, when the first rotary member portion and the second rotary member portion are rotated by engaging the gear portion of the first code plate portion with a gear portion of the first rotary member portion, and by engaging the gear portion of the second code plate portion with a gear portion of the second rotary member portion, the information on the first code plate portion is detected by the first detecting element portion, and the information on the second code plate portion is detected by the second detecting element portion, whereby the rotation angle of the first rotary member portion and the rotation angle of the second rotary member portion are separately detected.
Although not exclusive, in a preferred form of the invention, the first code plate portion and the second code plate portion may have the same center of rotation, with one side of the gear portion of the first code plate portion and one side of the gear portion of the second code plate portion being disposed such that they face each other, and the other side of the gear portion of the first code plate portion having formed thereat the information portion associated thereto and the other side of the gear portion of the second code plate portion having formed thereat the information recording portion associated thereto, the outside diameter of each information recording portion being larger than the outside diameter of the gear portion associated thereto. In addition, the first rotary member portion and the second rotary member portion may be rotatably interposed between the information recording portions.
Although not exclusive, in a preferred form of the invention, the rotary member, the code plate, and the detecting element may be accommodated in a box-shaped housing, and the code plate may be disposed between the detecting element and the rotary member.
Although not exclusive, in a preferred form of the invention, the information recording portion of the code plate may be composed of a magnetic material with a plurality of magnetic poles, and the detecting element may comprise a magnetic sensor which reacts with the magnetic field of the magnetic material.
According to a second aspect of the present invention, there is provided a torque sensor comprising a rotation angle sensor including a first rotary member and a second rotary member being separately rotatable and having the same center of rotation, each having a gear portion at the outer peripheral portion thereof and a shaft-inserting hole at the center of rotation thereof. In addition, the rotation angle sensor includes a first code plate and a second code plate being separately rotatable, the first code plate having a gear portion which engages the first rotary member and the second code plate having a gear portion which engages the second rotary member, the first code plate having an information recording portion which rotates in response to the rotation of the first rotary member and the second code plate having an information recording portion which rotates in response to the rotation of the second rotary member. Further, the rotation angle sensor includes a first detecting element for detecting information written on the first information recording portion, and a second detecting element for detecting information written on the second information recording portion. In the rotation angle sensor, when the first rotary member and the second rotary member rotate to rotate the first code plate and the second code plate, respectively, the first detecting element detects the information on the first code plate and the second detecting element detects the information on the second code plate, whereby the rotation angle of the first rotary member and the rotation angle of the second rotary member are detected. The torque sensor further comprises a first operating shaft and a second operating shaft, an end of the first operating shaft and an end of the second operating shaft being abutted against each other and connected by a resilient member, being a torsion bar. In the torque sensor, the first rotary member is supported by the end of the first operating shaft, and the second rotary member is supported by the end of the second operating shaft, in order to detect the rotation angle of the first operating shaft by the first detecting element and the rotation angle of the second operating shaft by the second detecting element, whereby the rotational torque on the first operating shaft is detected from the difference between the rotation angle of the first operating shaft and the rotation angle of the second operating shaft.
Although not exclusive, in a preferred form of the invention, a spring member may be provided at the inner peripheral surface of the edge of the shaft-inserting hole of the first rotary member and at the inner peripheral surface of the edge of the shaft-inserting hole of the second rotary member, the spring members resiliently pressing against the first and the second operating shafts in order to support the first rotary member by the first operating shaft and the second rotary member by the second operating shaft.
According to a third aspect of the present invention, there is provided an electrically driven power steering apparatus comprising a rotary angle sensor including a first rotary member and a second rotary member being separately rotatable and having the same center of rotation, each having a gear portion at the outer peripheral portion thereof and a shaft-inserting hole at the center of rotation thereof. In addition, the rotary angle sensor includes a first code plate and a second code plate being separately rotatable, the first code plate having a gear portion which engages the first rotary member and the second code plate having a gear portion which engages the second rotary member, the first code plate having an information recording portion which rotates in response to the rotation of the first rotary member and the second code plate having an information recording portion which rotates in response to the rotation of the second rotary member. Further, the rotation angle sensor includes a first detecting element for detecting information written on the first information recording portion, and a second detecting element for detecting information written on the second information recording portion. In the rotation angle sensor, when the first code plate and the second code plate are rotated as a result of rotation of the first rotary member and the second rotary member, respectively, the first detecting element detects the information on the first code plate and the second detecting element detects the information on the second code plate, whereby the rotation angle of the first rotary member and the rotation angle of the second rotary member are detected. The electrically driven power steering apparatus also comprises a vehicle handle side steering shaft for supporting the first rotary shaft, and a vehicle wheel side steering shaft for supporting the second rotary member, an end of the vehicle handle side steering shaft and an end of the vehicle wheel side steering shaft being abutted against each other and connected by a resilient member, being a torsion bar. The electrically driven power steering apparatus further comprises a motor used for providing assistance in turning a handle. In the apparatus, the rotation angle of the handle side steering shaft is detected by the first detecting element, and the rotation angle of the wheel side steering shaft is detected by the second detecting element, in order to detect the rotational torque on the first operating shaft from the difference between the rotation angle of the handle side steering shaft and the rotation angle of the wheel side steering shaft, whereby when the rotational torque exceeds a predetermined value, the motor starts to operate to provide assistance in turning the handle.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of a rotation angle sensor in accordance with the present invention, without a cover.
FIG. 2 is a sectional side view of the main portion of the rotation angle sensor in accordance with the present invention.
FIGS. 3A and 3B are external views of the rotation angle sensor in accordance with the present invention.
FIG. 4 is a plan view of a first rotary member of the rotation angle sensor in accordance with the present invention.
FIG. 5 is a sectional side view of the main portion of the first rotary member of the rotation angle sensor in accordance with the present invention.
FIG. 6 is a plan view of the portions of a spring member, in the process of being formed, of the rotation angle sensor in accordance with the present invention.
FIG. 7 is a plan view of the spring member of the rotation angle sensor in accordance with the present invention.
FIG. 8 is a side view of the spring member of the rotation angle sensor in accordance with the present invention.
FIGS. 9A, 9 B, and 9 C are a top view, a sectional side view, and a bottom view of a code plate of the angle sensor in accordance with the present invention.
FIG. 10 is a side view of the main portion of the steering shaft to which the rotation angle sensor of the present invention is mounted.
FIG. 11 is a schematic view of the rotation angle sensor of the present invention mounted to the steering shaft.
FIG. 12 is a schematic view of a conventional rotation angle sensor.
FIG. 13 is a schematic view of a torque sensor formed by mounting two conventional rotation angle sensors to the rotary shaft.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A description will now be given of a rotation angle sensor of the present invention with reference to FIGS. 1 to 11 . As shown in FIGS. 3A and 3B, which are external views of the rotation angle sensor of the present invention, the rotation angle sensor is formed by molding such that its inside is hollow. A substantially D-shaped housing 10 forms the outer portion of the rotation angle sensor.
A plate-shaped cover 11 , which has the same external form as the housing 10 , is placed onto the top portion of the housing 10 . It is affixed to the housing 10 with a plurality of screws 12 , whereby the top portion of the housing 10 is covered by the cover 1 .
As shown in FIG. 2, a circular opening 10 b is formed in substantially the center portion of a bottom wall 10 a of the housing 10 . A circular guide wall 10 c is formed along the circumference of the opening 10 b so as to protrude upwardly by a predetermined height.
Similarly, a circular opening 11 a is formed in substantially the center portion of the cover 11 . As shown in FIG. 2, a guide wall 11 b is formed along the circumference of the opening 11 a so as to protrude downwardly by a predetermined height.
A first rotary member 13 is inserted into the opening 11 a of the cover 11 , and is made of, for example, a molding material. FIG. 5 is a sectional side view of the main portion of the first rotary member 13 . The first rotary member 13 has a flange 13 a , shown at the bottom side of FIG. 5, and a gear portion 13 b , with a predetermined number of teeth and modules, shown in FIG. 4 that is a top view of the first rotary member 13 .
The first rotary member 13 has a bearing 13 c formed above the flange 13 a . The bearing 13 c is formed to a predetermined height and has a substantially flange-like external form.
As shown in FIG. 4, a circular, shaft-inserting hole 13 d is formed in the first rotary member 13 , at the center of rotation thereof, and a plurality of grooves 13 e , formed to a predetermined depth and width, are formed in an inner peripheral surface 13 h of the edge of the shaft-inserting hole 13 d , in the axial direction thereof. A plurality of rectangular protrusions 13 f are formed on the top surface of the bearing 13 c so as to protrude a predetermined height from the top surface of the bearing 13 c.
An annular protrusion 13 g is formed along the circumference of a portion, below the flange 13 a of FIG. 5, of the shaft-inserting hole 13 d , so as to protrude by a small height.
The bearing 13 c of the first rotary member 13 is inserted into the opening 11 a of the cover 11 , and is guided along the guide wall 11 b , formed along the circumference of the opening 11 a , such that it can rotate freely.
A first engaging spring 14 , such as that shown in FIGS. 6, 7 , and 8 , whose external shape is annular, is mounted to the top surface of the bearing 13 c of the first rotary member 13 . The first engaging spring 14 is formed of, for example, a springy stainless steel. As shown in FIG. 6, it has an annular frame portion 14 a , formed at the outer periphery of the first engaging spring 14 , and a plurality of spring portions 14 b , which extend from the frame portion 14 a into an opening 14 e of the first engaging spring 14 . The annular frame portion 14 a and the spring portions 14 b are formed by punching out, for example, stainless steel, by, for example, a pressing operation.
A plurality of square holes 14 c are formed in the frame portion 14 a by punching out a portion of the frame portion 14 a , and a square hole 14 d is formed towards an end of each spring portion 14 b by punching out a portion of the end of each spring portion 14 d . Each spring portion 14 b is formed such that its top portion, which is substantially cone shaped, includes its associated square hole 14 d.
As shown in FIG. 8, which is a sectional side view of the base portion of some of the spring portions 14 b , the first engaging spring 14 is bent downward. As shown in FIG. 7, which is a top view of the first engaging spring 14 , the first engaging spring 14 has a substantially circular opening 14 e.
As shown in FIG. 2, the square holes 14 c of the frame portion 14 a are inserted onto the protrusions 13 f , formed on the top surface of the bearing 13 c of the first rotary member 13 , and the ends of the protrusions 13 f protruding above their respective square holes 14 c are, for example, caulked by heating, whereby the first rotary member 13 and the first engaging spring 14 are integrally formed.
The downwardly bent spring portions 14 b are positioned in the grooves 13 e of the first rotary member 13 . The substantially cone-shaped top portion, including its associated square hole 14 d , of each spring portion 14 b protrudes from the inner peripheral surface 13 h of the edge of the shaft-inserting hole 13 d into the shaft-inserting hole 13 d of the first rotary member 13 .
At the lower side of FIG. 2 that opposes the first rotary member 13 is disposed a second rotary member 15 having substantially the same form as the first rotary member 13 . It comprises, for example, a gear portion 15 b , a bearing portion 15 c , and a shaft-inserting hole 15 d , formed at an inner peripheral surface 15 h of the second rotary member 15 .
A second engaging spring 16 , which has substantially the same form as the first engaging spring 14 and comprises a spring portion 16 b , etc., is mounted to the second rotary member 15 by using the same method as that used for mounting the first engaging spring 14 to the first rotary member 13 .
In other words, the first and second engaging springs 14 and 16 , serving as spring members, are disposed at the inner peripheral surfaces 13 h and 15 h of the edges of the shaft-inserting holes 13 d and 15 d of the first rotary member 13 and the second rotary member 15 , respectively.
The bearing portion 15 c of the second rotary member 15 is inserted into the opening 10 b of the housing 10 , and is guided along the guide wall 10 c , formed along the circumference of the opening 10 b , so that it can rotate freely.
The first rotary member 13 and the second rotary member 15 , mounted to the cover 11 and the housing 10 , have the same center of rotation and can rotate separately.
At the lower left side of the housing 10 of FIG. 1 are disposed a first code plate 17 , which engages the gear portion 13 b of the first rotary member 13 , and a second code plate 18 , which engages the gear portion 15 b of the second rotary member 15 .
As shown in FIG. 9, the first code plate 17 comprises a gear portion 17 a and an information recording portion 17 b . The gear portion 17 a engages the gear portion 13 b of the first rotary member 13 and is made of, for example, resinous material. The information recording portion 17 b is mounted to a side of the gear portion 17 a and is made of a magnetic material with a plurality of magnetic north-south (N-S) poles.
The information recording portion 17 b is formed into the shape of a disk with an outside diameter which is greater than the outside diameter of the gear portion 17 a . A protruding boss portion 17 c is formed at a side of the gear portion 17 a.
The boss portion 17 c , formed at a side of the gear portion 17 a , is press-fitted or bonded to a boss hole 17 d in the information recording portion 17 b , whereby the gear portion 17 a and the information recording portion 17 b are integrally formed together.
A shaft-inserting hole 17 e is formed through the first code plate 17 , at the center of rotation of the first code plate 17 . At a side surface 17 f of the gear portion 17 a are formed a spring groove 17 g , having a predetermined depth, and a groove 17 h for stopping rotation of a torsion coil spring (not shown) which is inserted into the spring groove 17 g.
A protrusion 17 j , which protrudes slightly from the side surface 17 f , is formed at the inner peripheral side of the edge of the spring groove 17 g.
As shown in FIG. 2, a second code plate 18 , with the same form as the first code plate 17 , is disposed at the lower side in FIG. 2 which opposes the gear portion 17 a of the first code plate 17 .
The second code plate 18 comprises a gear portion 18 a , which engages the gear portion 15 b of the second rotary member 15 , an information recording portion 18 b , a shaft-inserting hole (not shown), a protrusion (not shown), etc. A metallic supporting shaft is inserted into the shaft-inserting hole 17 e of the first code plate 17 and the shaft-inserting hole (not shown) of the second code plate 18 , and one side of the gear portion 17 a and one side of the gear portion 18 a are brought into contact with each other, in order to allow the code plates 17 and 18 to rotate separately.
The supporting shaft has its top end affixed to the cover 11 side and its bottom end affixed to the housing 10 side in order to accommodate the first code plate 17 and the second code plate 18 in the housing 10 .
The spring groove 17 g has inserted therein a torsion coil spring (not shown), which prevents backlash from occurring at the two code plates 17 and 18 .
A holder 22 is disposed at the left lower corner of the housing 10 of FIG. 1 . To the holder 22 are mounted first detecting elements 20 and second detecting elements 21 , being, for example, hole elements, for detecting information, that is magnetic information, written on the information recording portions 17 b and 18 b of the code plates 17 and 18 , respectively.
The portion of the holder 22 to which the detecting elements 20 and 21 are mounted has two nonparallel sides that incline towards each other. Two first detecting elements 20 are mounted to one of the nonparallel sides of the holder 22 , while two second detecting elements 21 are mounted to the other nonparallel side of the holder 22 , whereby they are mounted separately and vertically to the holder 22 . The first detecting elements 20 are mounted at a location opposing the information recording portion 17 b of the first code plate 17 , while the second detecting elements 21 are mounted at a location opposing the information recording portion 18 b of the second code plate 18 .
The holder 22 , to which the first detecting elements 20 and the second detecting elements 21 are mounted, has a flat back surface, which is, for example, bonded to a substrate 23 behind the back surface.
An integrated circuit (IC) 24 , which is used to perform computations on the information sent from the detecting elements 20 and 21 , is mounted to the insulating substrate 23 , and a lead wire 25 , for transmitting the information processed by the IC 24 to an external device, is mounted to the insulating substrate 23 , by soldering or the like.
A description will now be given of the case where the rotation angle sensor of the present invention is used to form a torque sensor and is applied to an automobile steering shaft.
As shown in FIG. 10, the automobile steering shaft 26 comprises, for example, a first operating shaft portion 27 and a second operating shaft portion 28 , with T-shaped grooves 27 b and 28 b being formed in ends 27 a and 28 a , respectively. These ends 27 a and 28 a are abutted against each other. A resilient member 29 , shown in black in FIG. 10, is inserted into the grooves 27 b and 28 b , whereby the first operating shaft portion 27 and the second operating shaft portion 28 are connected together. The resilient member 29 is, for example, a torsion bar.
The first rotary member 13 of a rotation angle sensor S of the present invention is inserted into the end 27 a of the first operating portion shaft portion 27 , and the second rotary member of the rotation angle sensor S is inserted into the end 28 a of the second operating shaft portion 28 .
As described above, the spring portions 14 b and 16 b of the first and second engaging springs 14 and 16 , being spring members, are disposed at the inner peripheral surfaces 13 h and 15 h of the edges of the shaft-inserting holes 13 d and 15 d of their respective first rotary member 13 and the second rotary member 15 . The spring portions 14 b and 16 b resiliently press against the first operating shaft portion 27 and the second operating shaft portion 28 , respectively, in order for the first rotary member 13 and the second rotary member 15 to be supported by the first operating shaft portion 27 and the second operating shaft portion 28 , respectively, whereby the rotation angle sensor S is mounted to the steering shaft 26 .
As shown in FIG. 11, the steering shaft 26 is constructed such that a handle 30 is mounted to the first operating shaft portion 27 , and the second operating shaft portion 28 is mounted to a wheel (not shown). When the handle 30 is turned to rotate the second operating shaft portion 28 , the rotational torque on the second operating shaft portion 28 becomes large due to, for example, the condition of the road surface (not shown) with which the vehicle wheels are in contact. In this case, when the first operating shaft portion 27 is rotated as a result of turning the handle 30 , the second operating shaft portion 28 , due to the resilient member 29 , is rotated later than the first operating shaft portion 27 , causing the rotation angles of the first operating shaft portion 27 and the second operation shaft portion 28 to differ.
This difference in rotation angles causes the rotation angles of the first code plate 17 and the second code plate 18 to differ. The rotation angle of the first code plate 17 and the rotation angle of the second code plate 18 are detected by the first detecting element 20 and the second detecting element 21 , respectively. The difference in the rotation angles of the code plates 17 and 18 are computed by means of the IC 24 , thereby allowing the rotational torque at the first operating shaft portion 27 side to be detected. Accordingly, the rotation angle sensor S of the present invention can be used to form a torque sensor.
The electrically driven power steering apparatus of the present invention comprises an electric motor (not shown), such as a motor which assists the operator in operating the handle 30 . When the handle 30 is turned, the torque sensor detects the rotational torque on the first operating shaft portion 27 . When the rotational torque on the first operating shaft portion 27 exceeds a predetermined value, an operation command is sent forth from the IC 24 towards the electric motor, through a driver, thereby actuating the electric motor.
The actuating force of the electric motor is used to assist the operator, who is turning the handle 30 with a certain turning force, in turning the handle 30 , whereby less rotational torque is exerted on the handle 30 .
Although in the foregoing description of the rotation angle sensor S of the present invention the information recording portions 17 b and 18 b of the code plates 17 and 18 were described as magnetic media, and the detecting elements 20 and 21 were described as magnetic sensors, the information recording portions 17 b and 18 b may be identification marks identifiable by, for example, an optical sensor, and the detecting elements may be, for example, optical sensors consisting of a light emitter and a light receiver.
According to the rotation angle sensor of the present invention, when the code plates are rotated as a result of turning the rotary members, the detecting elements detect information on their associated code plates in order to detect the rotation angles of their associated rotary members. Therefore, the code plates and the rotary members can be formed as separate members. Even when the rotary members are slightly displaced as a result of undue load on the rotary members, the undue load is not exerted onto the code plates, so that the amount of gap between the code plates and their associated detecting elements does not change.
Consequently, it is possible to provide a rotation angle sensor which can detect the angle of rotation of a rotary member precisely, even when an undue load is exerted onto the rotary member.
In addition, the rotation angle sensor comprises first and second rotary members which can rotate separately and which have the same center of rotation; first and second code plates which have gear portions that engage their respective rotary members and which can rotate separately; and first and second detecting elements for detecting information on their associated first code plate and second code plate. When the first rotary member and the second rotary member are rotated by engaging the gear portion of the first code plate with the gear portion of the first rotary member, and by engaging the gear portion of the second code plate with the gear portion of the second rotary member, the information on the first code plate is detected by the first detecting element, and the information on the second code plate is detected by the second detecting element, so that the rotation angles of the first rotary member and the second rotary member can be separately detected. Therefore, the code plates and the rotary members can be formed as separate component parts through the gear portions, so that even when an undue load is exerted onto the rotary members, it is possible to support the code plates without backlash. The rotation angle sensor can be used for a torque sensor which can detect the rotational torque on the first rotary member and the second rotary member, from the difference between the rotation angles of the two rotary members detected by their associated two code plates.
Further, according to the rotation angle sensor, the first and second code plates have the same center of rotation, with the gear portions being disposed such that one side of one of the gear portions and one side of the other of the gear portions oppose each other. The information recording portions are formed on the other sides, not facing each other, of the gear portions, such that their outside diameters are larger than the outside diameters of their respective gear portions. The first and second rotary members are rotatably interposed between the information recording portions. By virtue of such a structure, the outside dimensions of the information recording portions of the code plates can be made large, thereby allowing the rotation angles to be detected with high precision.
Still further, since the rotary members are interposed between the information recording portions, the outside dimensions of the rotation angle sensor do not become large, even when the outside dimensions of the information recording portions are large.
Still further, the rotary members, the code plates, and the detecting elements are accommodated in a box-shaped housing such that the detecting elements are disposed at a corner of the housing, and the code plates are disposed between the detecting elements and their associated rotary members. Therefore, the outside dimensions of the rotation angle sensor can be made small.
Still further, the code plates each have an information recording portion made of magnetic material with a plurality of magnetic poles, and the detecting elements are magnetic sensors which react to the magnetic field of the magnetic material. Therefore, when the magnetic field is varied as a result of rotating the code plates, the magnetic field variation can be detected by the detecting elements with high precision. Consequently, it is possible to provide a rotation angle sensor which can detect the rotation angle of a rotary member with high precision.
Still further, since the magnetic members around the shaft-inserting holes of the rotary members do not have to be formed to large diameters, the rotation angle sensor can be formed to the minimum size required. Therefore, a cheap rotation angle sensor can be provided.
The torque sensor of the present invention comprises a rotation angle sensor including a first rotary member and a second rotary member being separately rotatable and having the same center of rotation, each having a gear portion at the outer peripheral portion thereof and a shaft-inserting hole at the center of rotation thereof. In addition, the rotation angle sensor includes a first code plate and a second code plate being separately rotatable, the first code plate having a gear portion which engages the first rotary member and the second code plate having a gear portion which engages the second rotary member, the first code plate having an information recording portion which rotates in response to the rotation of the first rotary member and the second code plate having an information recording portion which rotates in response to the rotation of the second rotary member. Further, the rotation angle sensor includes a first detecting element for detecting information written on the first information recording portion, and a second detecting element for detecting information written on the second information recording portion. In the rotation angle sensor, when the first rotary member and the second rotary member rotate to rotate the first code plate and the second code plate, respectively, the first detecting element detects the information on the first code plate and the second detecting element detects the information on the second code plate, whereby the rotation angle of the first rotary member and the rotation angle of the second rotary member are detected. The torque sensor also comprises a first operating shaft and a second operating shaft, an end of the first operating shaft and an end of the second operating shaft being abutted against each other and connected by a resilient member, being a torsion bar. In the torque sensor, the first rotary member is supported by the end of the first operating shaft, and the second rotary member is supported by the end of the second operating shaft, in order to detect the rotation angle of the first operating shaft by the first detecting element and the rotation angle of the second operating shaft by the second detecting element, whereby the rotational torque on the first operating shaft is detected from the difference between the rotation angle of the first operating shaft and the rotation angle of the second operating shaft. By virtue of this structure, the rotation angle sensor can detect with high precision the difference between the rotation angle of the first operating shaft and the rotation angle of the second operating shaft. An IC performs computations on the difference of the rotation angles in order to convert it to a torque value, whereby the rotational torque on the first operating shaft can be detected with high precision.
In the torque sensor, a spring member is provided at the inner peripheral surface of the edge of the shaft-inserting hole of the first rotary member and at the inner peripheral surface of the edge of the shaft-inserting hole of the second rotary member, the spring members resiliently pressing against the first and the second operating shafts in order to support the first rotary member by the first operating shaft and the second rotary member by the second operating shaft. Therefore, the rotary members can be supported by their respective operating shafts, while the spring members resiliently press against the operating shafts, by merely fitting the rotary members into their respective operating shafts.
Consequently, it is possible to provide a torque sensor which allows the rotary members to be easily mounted to the operating shafts, without slippage of the rotary members with respect to the operating shafts.
The electrically driven power steering apparatus comprises a rotation angle sensor including a first rotary member and a second rotary member being separately rotatable and having the same center of rotation, each having a gear portion at the outer peripheral portion thereof and a shaft-inserting hole at the center of rotation thereof. In addition, the rotation angle sensor includes a first code plate and a second code plate being separately rotatable, the first code plate having a gear portion which engages the first rotary member and the second code plate having a gear portion which engages the second rotary member, the first code plate having an information recording portion which rotates in response to the rotation of the first rotary member and the second code plate having an information recording portion which rotates in response to the rotation of the second rotary member. Further, the rotation angle sensor includes a first detecting element for detecting information written on the first information recording portion, and a second detecting element for detecting information written on the second information recording portion. In the rotation angle sensor, when the first code plate and the second code plate are rotated as a result of rotation of the first rotary member and the second rotary member, respectively, the first detecting element detects the information on the first code plate and the second detecting element detects the information on the second code plate, whereby the rotation angle of the first rotary member and the rotation angle of the second rotary member are detected. The electrically driven power steering apparatus also comprises a vehicle handle side steering shaft for supporting the first rotary shaft, and a vehicle wheel side steering shaft for supporting the second rotary member, an end of the vehicle handle side steering shaft and an end of the vehicle wheel side steering shaft being abutted against each other and connected by a resilient member, being a torsion bar. The apparatus further comprises a motor used for giving assistance in turning a handle. In the apparatus, the rotation angle of the handle side steering shaft is detected by the first detecting element, and the rotation angle of the wheel side steering shaft is detected by the second detecting element, in order to detect the rotational torque on the first operating shaft from the difference between the rotation angle of the handle side steering shaft and the rotation angle of the wheel side steering shaft, whereby when the rotational torque exceeds a predetermined value, the motor starts to operate for giving assistance in turning the handle. By virtue of this structure, it is possible to provide an electrically driven power steering apparatus which can detect the rotational torque on an operating shaft with high precision and which can provide high performance utilizing the rotational torque detected with high precision. | A rotation angle sensor wherein when code plates rotate as a result of rotation of rotary members, detecting elements detect information on information recording portions of the code plates in order to detect the rotation angles of the rotary members. Therefore, the rotation angles of the rotary members can be detected with high precision. In conventional rotation angle sensors, a rotary drum, being a magnetic medium, is mounted directly to a rotary shaft. Therefore, when two such conventional rotation angle sensors are mounted to a rotary shaft, and a rotational torque is applied to a drive shaft portion in order to rotate a load shaft portion, so that a large load is applied to the load shaft portion, the drive shaft portion and the load shaft portion may become decentered. This causes the gap between one of the two rotary drums and its associated detecting sensor as well as the gap between the other of the two rotary drums and its associated detecting sensor to vary, making it impossible to precisely detect the difference between the rotation angles of the two rotary drums. The rotation angle sensor of the invention overcomes this problem. | 6 |
BACKGROUND OF THE INVENTION
The present invention relates to electrical switches for use in superconductive systems. More particularly, the present invention relates to switches for use in superconductive systems which store high levels of electrical and magnetic energy, particularly in the form of persistent current loops.
In conventional superconductive electrical systems in which persistent current loops are present, the cessation of current is typically accomplished through the act of heating a portion of the superconducting conductor to a point above its transition temperature. Once a portion of the current loop exhibits a finite resistance, electrical energy is dissipated in accordance with the well known I 2 R law of power dissipation, where I is the current and R the resistance of the circuit. The heat that is generated, quickly causes adjacent areas of the conductor to also enter the resistive state and in a very short time the persistent current is quenched. However, when the level of current in the persistent loop is high, large levels of electrical energy must be dissipated in a short time in a small volume. When this is the case, a transition to the resistive state in order to turn off the current in the windings can result in damage to the superconductive material, particularly in the switch. Furthermore, in order for the switch portion of the superconductive wire to provide the necessary electrical resistance in its resistive state, the switch conductor must in some applications be quite long, 1,500 feet being a representative length. This length of wire must be compactly and firmly supported since small movements of superconductive conductors can cause them to switch into the normal, resistive state at an unacceptably low current level. Furthermore, because of the high levels of energy that must be dissipated, the material which is employed in the switch must have sufficient thermal mass to dissipate the energy in the current loop when the transition to the resistive state is made. Furthermore, the thermal conductivity of the switch must be high enough to prevent hot spots from forming that would otherwise damage the switch structure. However, since the switch is part of the persistent superconducting current loop, it must be maintained at a temperature below the transition point. With most materials that are presently available which exhibit superconductive properties, the transition temperature is typically below about 10° K., although some transition temperatures are higher. Accordingly, the superconductive circuit must be contained within a coolant, such as liquid helium. However, the presence of a superconducting switch in such a coolant could produce the boiling of unacceptably large quantities of liquid helium. Typically boiled off helium vapor is vented to the atmosphere. Accordingly, it is highly desirable to provide thermal insulation between the superconductive conductor in the switch and the coolant in which the switch is disposed. Furthermore, since a switch is typically contained within a bath at a temperature of about 4.2° K., it is necessary to insure that all materials employed in the switch are compatible with the coolant and the temperature ranges encountered in the environment. Accordingly, thermal expansion coefficients of the materials employed are important considerations. The switch sould also have a thermal insulating jacket that allows the switch body to be raised above the temperature of the coolant in which it is immersed. Even relatively small leaks of liquid helium through a thermally insulating jacket could allow unacceptably large heat losses. Insulating materials that could be employed, such as nylon and polytetrafluoroethylene (PTFE), which have desirably low thermal conductivities, also exhibit a high degree of shrinkage at liquid helium temperatures and they tend to leak. Accordingly, it is seen that a switch for use in superconducting current loops carrying high levels of electrical energy must be carefully designed to exhibit not only superconductivity, but also finite levels of resistance in a thermally harsh and varying environment and should be able to dissipate large quantities of electrical and thermal energy without developing hot spots when the switch is made resistive.
SUMMARY OF THE INVENTION
In accordance with a preferred embodiment of the present invention, a persistent current switch for high energy superconductive circuits comprises a length of superconductive conductor wire disposed in a compact volume together with a means for thermally insulating this volume and means disposed within the volume for heating at least a portion of the superconductive conductor. Furthermore, the switch includes a mass of thermally conductive material in thermal contact with a substantial portion of the superconductive conductor so as to hasten the transition of the switch material to a resistive state and to prevent the formation of localized hot spots which could deleteriously effect future switch operation. Additionally, the superconductive conductor in the switch of the present invention is preferably disposed as a bifilar winding about a central cylindrical core of glass fiber and epoxy. Furthermore, the switch is preferably surrounded by an aluminum enclosure. The superconductive winding core is preferably disposed in thermal contact with a material such as copper however, a thin, electrically insulating layer is disposed between the superconductive material and the copper which functions as a means for assuring rapid, even, thermal dissipation throughout the insulated switch volume.
Accordingly, it is an object of the present invention to provide a superconducting switch exhibiting relatively high electrical resistance in the normal, resistive state.
It is an additional object of the present invention to provide a superconductive switch exhibiting sufficient thermal mass and diffusivity to dissipate large amounts of electrical energy as a result of transition to the resistive state.
It is also an object of the present invention to provide a superconductive switch which is thermally insulated from a liquid coolant medium in which it is immersed.
It is a still further object of the present invention to provide a superconductive switch for high persistent current levels and which is capable of operation in the adverse environment found within coolants such as liquid helium.
It is also an object of the present invention to provide a superconductive switch which is relatively immune to problems caused by thermal expansion and contraction.
DESCRIPTION OF THE FIGURES
The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of practice, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings in which:
FIG. 1 is a schematic electrical circuit diagram illustrating a typical system in which the switch of the present invention is employed;
FIG. 2 is a cross-sectional side elevation view of a persistent current superconducting switch in accordance with the present invention;
FIG. 3 is an end view of the switch shown in FIG. 2;
FIG. 4 is a cross-sectional side elevation view of a portion of a single layer of the superconductive winding shown in FIG. 2.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic electrical circuit diagram illustrating a typical circuit in which the switch of the present invention is employed. In this circuit coils 100, 101 and 102, and switch 20 comprise superconductive material such as alloys of niobium and titanium. Additionally, the conductors connecting coils 100, 101, 102 and switch 20 in a circular current loop, also comprise superconductive material. These circuit elements are typically disposed within a coolant bath such as liquid helium so as to maintain their temperature below the critical temperatures for superconductivity (typically about 10° K.). Additionally, certain joints, namely those designated as nodes 120a, 120b, 120c, 120d, and 120e are specifically designated as being joints between superconductive materials and, in fact, these joints themselves exhibit the zero resistance property at the appropriate temperature. The other nodes designated in the circuit in FIG. 1, namely nodes 130a, 130b, 130c, and 130d, do not necessarily have to comprise superconductive joints. Superconductive coils 100, 101, and 102, are preferably connected in parallel with conventional resistive elements 110, 111, and 112, respectively. These conventional resistive elements provide a means for dissipating energy within the coils in the event that the corresponding coil enters the resistive or ohmic state and limits the energy transfer to the persistent current switch during a switch quench by providing a current path parallel to the protected circuit elements.
Under normal startup conditions, coils 100, 101 and 102, and any inter-connecting wires are cooled to below their critical temperatures. At this time, DC power supply 140 is connected to the circuit through switch 141 and the current from the power supply is slowly increased to the desired level of operating current I o . In applications contemplated in the present invention, I o is typically between approximately 500 and 2,000 amperes. During the transition to this final steady state current value, the voltage V across the series connection of coils 100, 101, and 102, (that is, the voltage V between nodes 130a and 130d) obeys the relation V=L di/dt, where V is the voltage, L is the equivalent inductance of the three coils, and i is the current through the coils. During this transition period, element 20 in switch 10 is typically still in the normal resistive state and it is therefor required to dissipate energy at the rate of V 2 /R, where R is the resistance of element 20 when this element is in its ohmic or non-superconductive state. Accordingly, it is seen that in order to minimize power dissipation in switch 10 during startup, it is necessary to insure that R is a reasonably large value. As di/dt goes to zero, and as the superconductive element in switch 10 reaches a temperature below the critical temperature, the voltage across switch 10 and all voltage drops around the current loop go to zero and it is then possible to remove power supply 140 from the circuit.
The circuit of FIG. 1 is particularly useful in producing high strength, uniform magnetic fields for nuclear magnetic residents (NMR) imaging applications. In such applications, a high strength, highly uniform magnetic field is required. In particular, the magnetic field strength for such applications ranges between about 0.04 and about 1.5 Tesla, or more. In these applications, it is important that the magnetic fields generated by the conductors in the superconducting loop do not produce stray magnetic fields of their own which could deleteriously affect the uniformity of the field that is otherwise produced by coils 100, 101, and 102. Accordingly, in such applications it is either necessary that element 20 in switch 10 be wound in a bifilar fashion so as to minimize any stray magnetic field produced or switch 10 must be located in a position sufficiently far from the main winding coils 100, 101 and 102. However, this latter positioning is generally not preferred since it is desired to dispose all of the superconductive circuit elements within a single coolant bath.
Accordingly, it is seen that the requirements of the circuit of FIG. 1 dictate that superconductive circuit element 20 should exhibit a high normal resistance value. In general, the resistance of a resistive circuit element may be controlled by varying the material, its length, or its cross-sectional area. In the present situation, the material of element 20 is already determined by the requirement that it comprises, at least in part, a superconductive material. The form of the superconductor is a composite of filaments of superconductive alloy embedded in a matrix of normally conducting material such as copper, aluminum, or more rarely, copper-nickel alloy. Higher normal resistance can be achieved by minimizing the matrix cross-section or increasing the resistivity. The practical lower limit of the matrix/superconductor ratio is approximately 1:1 but a ratio of approximately 1.5:1 produces an acceptable switch with copper matrix wire. Lower ratios and higher resistivity matrix material (such as copper nickel alloy) produces more efficient switching, but greater care must be given to the lead wire design to insure stability at high current density levels. An acceptable value of normal switch resistance for the circuits herein contemplated is approximately 0.03 ohms. For a specific design, this resistance entails a conductor length of approximately 1,500 feet. While it is also theoretically possible to control the resistance of element 20 through the utilization of conductors having a small cross-sectional area, this design is highly impractical since it can lead to the formation of localized hot spots during switch operation. Accordingly, it is seen then that element 20 in switch 10 should comprise a relatively long length of conductor in order to achieve the desired relatively large value for R. Typically, the value of R for circuits that are contemplated herein is approximately 0.03 ohms. This value of R may be effected by a conductor length of approximately 1,500 feet.
Much of the above description is related to the turning on of switch 10 in order to effect the formation of a high intensity current loop comprising element 20, coils 100, 101, and 102, and their associated adjoining leads and superconductive joints 120a-e. When it is desired to turn switch 10 off, that is to switch element 20 to its resistive state, it is only necessary to supply a relatively small amount of energy to heater coil 30 through leads 31a and 31b. Typically, a power dissipation in coil 30 of approximately 2.5 watts for a period of as little as one second is sufficient to trigger the superconductive to resistive state transition. However, the design of switch 10 should be such that, as a result of the transition, the relatively high levels of energy which are dissipated in switch 10 do not result in the formation of destructive hot spots. For this reason, it is desirable to have the superconductive conductor in element 20 disposed in a compact configuration to promote thermal diffusion. At the same time, it is necessary to insure electrical insulation between the various turns of element 20. Moreover, since superconductivity may be defeated, especially locally, by means of slight motion of the superconductors, it is also desirable to provide rigid support for the entire structure. Accordingly, it is seen that switch 10 should comprise superconductive wire disposed so that the various portions of the wire are electrically insulated from one another but yet at the same time maintained in close thermal contact in a rigid structure. Furthermore, it is seen that switch 10 should also possess element 20 configured so as to exhibit minimum stray magnetic field production. Additionally, since switch 10 is preferably disposed within a coolant, say at 4.2° K., and since a temperature rise of the switch to above the critical temperature is necessary to turn the switch off, the switch's mass of superconductor should be thermally insulated from the coolant bath to minimize the heater power and the time lag to initiate the transition to the normally conducive stage. The degree of thermal insulation should be carefully chosen, however, since an overly effective insulation unacceptably delays the re-cooling to the superconducting state and thus prolongs the cycle time to the succeeding switch-on condition.
A switch satisfying all these criteria is illustrated in FIGS. 2-4. FIG. 2 in particular illustrates a cross-sectional view through a switch in accordance with the present invention. In particular, superconductive element 20 is shown as a cylindrical coil disposed about glass fiber/epoxy core 60. Heating element coil 30 having leads 31a and 31b is shown disposed in helical fashion between core 60 and superconductive winding layers 20. Winding layers 20 are configured in a bifilar arrangement of conductors so as to minimize stray magnetic field production. Additionally, surrounding annular superconductive winding 20, there is disposed a thermally insulating sleeve 40 comprising a material such as nylon or polytetraflouroethylene (PTFE). Additionally, between thermal insulation 40 and superconductive winding 20, there is also preferably disposed compressible layer 44 comprising a material such as leather or cellulose. Lastly, thermal jacket 40 is preferably surrounded by metal jacket 45 preferably comprising a material exhibiting a high coefficient of thermal expansion. Such materials, when subjected to the cold temperatures of the liquid coolant bath tend to shrink and to produce forces which tend to hold the elements of the switch in close thermal contact. Similar structures are likewise provided at each end of cylindrical switch 10. In particular, flat annular disks or washers 43, comprising compliant material such as leather or cellulose are disposed at the ends of coil 20, as shown. Additional thermal insulation for the ends of the switch is provided by thermally insulating disks 41a and 41b which typically comprise material similar to jacket 40, namely nylon or polytetrafluoroethylene. Finally, each end of cylindrical switch 10 is capped by an annular metal (preferably aluminum) cap such as 46a or 46b. The structure is held together, at least in part, by means of bolt 47 and nut 48. Bolt 47 is disposed through central apertures in disk 46a, 41a, 41b and 46b respectively. Additionally, it is seen that the shaft of bolt 47 is disposed through a central bore in core 60. With respect to core 60 it is also pointed out that it preferably comprises a glass fiber and epoxy structure in which the layers of glass are oriented at right angles with respect to the longitudinal direction of bolt 47. Apertures are also provided in disks 41a and 46a for the passage therethrough of superconductive leads 21a and 21b which are integral with superconductive winding 20 and for the passage of normal resistive leads 31a and 31b which are connected to helical heating element 30. Heating element 30 typically comprises Nichrome wire. The foregoing structure insures that even at low operating temperatures, there exists excellent thermal insulation between the interior of switch 10 and the coolant bath in which it is disposed.
FIG. 3 illustrates an end view of the switch shown in FIG. 2. In particular, FIG. 3 further illustrates the fact that jacket 45 may be provided with flanges 49 through which bolts 49a are disposed so that nut 49b may be adjusted to further hold jacket 45 in position about insulating jacket 40.
It is also seen that a cylindrical shell 44 of compliant material may also be disposed about superconductive winding 20.
FIG. 4 illustrates a portion 20' of superconductive winding 20. In particular, there is shown superconductive windings 25 disposed on a sheet of thermally conductive material 50. Sheet 50 preferably comprises a high thermal conductivity material such as copper. Sheet 50 acts to provide a path of low thermal impedance in the axial direction as well as to provide thermal mass to absorb magnetically stored energy from the discharging magnet coils 100, 101 and 102. Each insulated superconductive conductor 25 preferably comprises a plurality of niobium-titanium filaments or wires disposed within a matrix of conductive material such as copper, aluminum, or copper-nickel alloy. Typically the ratio of matrix to superconductor cross section is in the range of from about 1 to about 2. Additionally, each sheet 50 of thermally conductive material has disposed thereon insulating layers 51a and 51b to provide the desired electrical insulation between turns and between winding layers. Because superconductivity may be dependent, at least in part, upon the rigidity of the structure, winding 20 is preferably potted in a hardenable compound such as epoxy. In particular, such a compound preferably fills gaps 26 between adjacent windings and wicks into glass cloth, 51a, 51b, dispersed between layers in coil 20. Sheet 50 is typically approximately 0.01 inches to approximately 0.02 inches thick. Glass fiber cloth 51a and 51b is typically only about 2 mil. thick. Sheet 50 is also preferably plated on both sides with insulation such as Formex® to insure a good bond to the epoxy resin with which coil 20 is vacuum impregnated prior to assembly.
From the above, it may be appreciated that the persistent current switch of the present invention provides the features which are desired in such a switch. In particular, it is seen that the switch may be manufactured and configured so as to be able to contain long lengths of superconductive material. While the above description is directed to the configuration in which the superconductive winding 20 is disposed as an annular, bifilar coil, other configurations may also be employed, as long as winding 20 is arranged in close thermal contact with itself. This generally requires disposition within a relatively compact volume. It is also seen that the switch of the present invention provides a compact and firm support for this relatively long length of superconductive material so that movements of the wires do not tend to cause the switch to enter the resistive state at unacceptably low levels of current. In addition, it is seen that the switch of the present invention exhibits a relatively large thermal mass in order to dissipate the energy associated with the excited superconducting solenoids in the transition to the resistive state. It is also seen that the switch of the present invention exhibits sufficient thermal conductivity during such transitions so that hot spots within the switch do not develop. It is also seen that the switch of the present invention exhibits thermal insulating structures that allow the switch to be raised above the temperature of the liquid coolant in which it is immersed so that unacceptably large heat transfer to the coolant does not occur. It is furthermore seen that the switch of the present invention comprises materials which are well suited to the harsh temperatures and conditions to which it is exposed.
While the invention has been described in detail herein in accord with certain preferred embodiments thereof, many modifications and changes therein may be effected by those skilled in the art. Accordingly, it is intended by the appended claims to cover all such modifications and changes as fall within the true spirit and scope of the invention. | Electrical switches used in conjunction with high energy superconductive windings must be able to quickly absorb large amounts of electrical energy since switching of the superconducting current is accomplished by means of transition to the resistive state in the switch portion of the superconducting current loop. Furthermore, to minimize the heat generated during the transition to the resistive state, the switch itself should exhibit a relatively high resistance while at the same time exhibiting a low external magnetic field. The switch should also exhibit minimal stray magnetic fields, especially in those applications requiring field uniformity. These objectives are achieved in a persistent current switch which includes a length of superconductive material disposed in a compact, thermally insulated volume which also includes a mechanism for heating at least a portion of the superconductive conductor in the switch in order to return it to its resistive state. Furthermore, there is included a mass of thermally conductive material within the volume which is in thermal contact with at least a substantial portion of the superconductive conductor to mitigate the effects of hot spots occuring within the switch. | 8 |
RELATED APPLICATIONS
The present application is a continuation of U.S. patent application Ser. No. 09/989,563 filed on Nov. 19, 2001, which is a continuation of U.S. patent application Ser. No. 09/387,263 filed on Aug. 31, 1999, which issued as U.S. Pat. No. 6,351,180 B1 on Feb. 26, 2002, the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to semiconductor integrated circuits. More specifically, the present invention relates to differential voltage regulators used in semiconductor devices
2. Description of the Related Art
A semiconductor device may be designed for any of a wide variety of applications. Typically, the device includes logic circuitry to receive, manipulate or store input data. The circuitry subsequently generates the same or modified data at an output terminal of the device. Depending on the type of semiconductor device or the circuit in which it is used, the device typically includes circuits which provide internal power signals that are regulated to be substantially independent of fluctuations in the externally generated power input signal.
An example of a data storage or memory device having such internal power signal circuits is the DRAM (dynamic random access memory). Conventionally, the DRAM receives an external power signal (V CCX ) having a voltage intended to remain constant, for example, at 4.5 volts measured relative to ground. Internal to the DRAM, the power regulation circuit maintains an internal operating voltage signal (V CC ) at a designated level, for example, 2.5 volts. Ideally, V CC linearly tracks V CCX from zero volts to the internal operating voltage level, at which point V CC remains constant as V CCX continues to increase in voltage to the designated V CCX level.
DRAMs also typically include a regulated constant pumped supply voltage (V CCP ) which is greater than V CC , for example, four volts. Conventionally, the pumped voltage drives the word lines of a DRAM. The DRAM has memory arrays comprising a number of intersecting row and column lines of individual transistors or memory cells. The pumped voltage needs to be greater than V CC to ensure that memory access operations, such as a memory cell read or a memory cell write, are performed both completely and quickly. Ideally, V CCP does not fluctuate. If V CCP is too high, damage to the memory cells may result. If it is too low, the memory chip may have poor data retention or may otherwise operate incorrectly. Depending on the type of memory device, the device may include a second circuit for providing this internal regulated pumped power signal.
Previously implemented CMOS (complementary metal-oxide semiconductor) power regulation circuits for regulating V CCP include an input stage comprising a series of diodes and an inverter circuit having a “trip point” to trigger the point at which the inverter circuit activates the charge pump for V CCP . The series of diodes, which are implemented through a combination of PMOS/NMOS (p-channel MOS/n-channel MOS) transistors, are used to translate the V CCP signal down to the input trip point range for controlling the inverter circuit. The inverter circuit provides an output signal which drives an amplifier (implemented as a series of inverters) to bring the output signal to full CMOS levels.
Semiconductor devices are typically tested extensively by the manufacturer at pre-set voltage levels prior to shipping. These tests are performed under controlled conditions and high V CCP voltage levels may be used to ensure the devices are operating properly. However, some customers may choose to perform their own reliability tests on the devices once they are received. Because the customers' tests are not always performed under the proper conditions, high V CCP voltage levels used during these tests may damage the semiconductor devices due to over-stress. The damaged devices will then fail the reliability tests, even though the device was operating properly when shipped.
What is desired is a circuit that generates a high V CCP voltage level on a semiconductor device for use during testing by the manufacturer, but then limits the V CCP voltage level the circuit generates once the device is shipped. This prevents a customer from inadvertently damaging the device by applying an over-voltage outside of controlled conditions.
SUMMARY OF THE INVENTION
The present invention involves limiting the supply voltage of a semiconductor device after the manufacturer's testing is complete. The testing of the semiconductor device is accomplished under controlled conditions. A voltage control circuit limits the maximum supply voltage to a first level during testing of the device using a plurality of voltage regulation devices. The maximum supply voltage available during testing is high enough to cause damage to the semiconductor device if the voltage is applied under non-controlled conditions. To prevent a customer from damaging the semiconductor device, the voltage control circuit reduces the maximum supply voltage to a non-harmful level prior to shipping. This allows the customer to perform its own reliability tests without damaging the device. The voltage control circuit uses fuses to limit the maximum supply voltage. After the manufacturer's testing is completed, the maximum supply voltage is limited by blowing fuses to bypass some of the voltage regulation devices.
One aspect of the invention is a voltage control circuit which provides a test supply voltage during manufacturing and testing of a semiconductor device and which provides an operational supply voltage after certification of the semiconductor device. The operational supply voltage is lower than the test supply voltage. The voltage control circuit includes a clamp circuit having a plurality of voltage regulation devices. The voltage regulation devices control a clamping threshold of the clamp circuit. A voltage regulator is electrically coupled to the clamp circuit and generates a first control signal responsive to the clamping threshold of the clamp circuit. A charge pump then receives the control signal from the voltage regulator, and, based on the value of the control signal, the charge pump generates the test supply voltage. At least one bypass device is connected to at least one of the plurality of voltage regulation devices. The bypass device is activated following the certification of the semiconductor device. Once activated, the bypass device bypasses the respective voltage regulation device from the clamp circuit to lower the clamping threshold of the clamp circuit. The voltage regulator then generates a second control signal responsive to the lowered clamping threshold of the clamp circuit. The second control signal is provided to the charge pump to generate the operational supply voltage. In one embodiment, the plurality of voltage regulation devices comprise diodes, which may be implemented through transistors. The bypass device may include a fuse.
Another aspect of the invention is a method of providing a first supply voltage on a semiconductor device during a first period and a second supply voltage during a second period. The method comprises the steps of providing a plurality of voltage control elements and establishing a first voltage control signal from the voltage control elements. The first supply voltage is then generated from the first voltage control signal. The method further comprises bypassing at least one of the voltage control elements and establishing a second voltage control signal from the voltage control elements which are not bypassed. The second supply voltage is then generated from the second voltage control signal. The first supply voltage has a voltage magnitude greater than the second supply voltages.
Another aspect of the invention is a voltage control circuit comprising a plurality of voltage regulation devices which limit an output voltage generated from an input voltage. A voltage regulation circuit receives the output voltage and generates a corresponding control signal. A charge pump receives the control signal and adjusts the voltage of a supply voltage based on the control signal. At least one voltage limiting device is coupled to a corresponding voltage regulation device. Each voltage limiting device is capable of selectively bypassing a corresponding voltage regulation device to further limit the output voltage, thereby reducing the voltage of the supply voltage.
Another aspect of the invention is a method of controlling a supply voltage in a semiconductor device. The method comprises the steps of providing an input voltage to a voltage regulator and establishing a target voltage of the input voltage. A reference voltage is adjusted when the input voltage reaches the target voltage. The method further comprises setting a control signal based on the reference voltage and generating the supply voltage based on the control signal. The target voltage is then decreased to limit the voltage level of the supply voltage.
Another aspect of the invention is a voltage control circuit which provides a test supply voltage during manufacturing and testing of a semiconductor device and an operational supply voltage after certification of the semiconductor device. The operational supply voltage is lower than the test supply voltage. The voltage control circuit comprises means for controlling an output of a clamp circuit and means for generating a first control signal based upon the output of the clamp circuit. The voltage control circuit further comprises a means for generating the test supply voltage and a means for limiting the output of the clamp circuit. A means for generating a second control signal is based upon the limited output of the clamp circuit. The limited output of the clamp circuit is then used to generate the operational supply voltage.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features and advantages of the invention will become more apparent upon reading the following detailed description and upon reference to the accompanying drawings, in which;
FIG. 1 is a block diagram illustrating a voltage circuit according to the teaching of the present invention;
FIG. 2 is a block diagram illustrating in detail the V CCP regulator circuit of FIG. 1 ;
FIG. 3 , consisting of FIGS. 3A and 3B , is a schematic diagram of the V CCP Regulator circuit of FIG. 2 ;
FIG. 4 , consisting of FIGS. 4A and 4B , is a schematic diagram of the V CCP Regulator circuit of FIG. 3 including fuse options according to the present invention; and
FIG. 5 is a graph showing the value of V CCP over a range of V CCX both without the fuse option and with the fuse option according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is a block diagram illustrating a voltage control circuit 100 according to the present invention. The voltage control circuit 100 includes a V CCP regulator 110 , a charge pump 120 , and a feedback signal line 130 . The V CCP regulator 110 generates an output signal V CCP-ON 115 which controls the charge pump 120 . The charge pump 120 receives two inputs, a regulated voltage V CCR and the output signal V CCP-ON from the V CCP regulator 110 . The output 125 of the charge pump 120 is the voltage V CCP . The voltage V CCP is fed back to as input to the V CCP regulator by the feedback signal line 130 .
The value of the signal V CCP-ON 115 controls the operation of the charge pump 120 . When V CCP is below the desired level, the signal V CCP-ON 115 causes the charge pump 120 to turn on, thereby increasing the value of V CCP . When V CCP is above the desired level, the signal V CCP-ON causes the charge pump 120 to turn off, thereby decreasing the value of V CCP . The charge pump 120 generates V CCP at a value of approximately 1.5 volts above V CCR so that V CCP tracks V CCR as V CCR increases and decreases. The charge pump 120 is conventional and may be implemented using any of a number of circuits.
FIG. 2 further illustrates the V CCP regulator 110 of FIG. 1 . The V CCP regulator 110 includes a clamp circuit 210 , a voltage regulator 220 , and a control circuit 230 . The clamp circuit 210 is used to place an upper limit on V CCP as V CCP increases. In particular, as discussed below, when V CCP increases above a predetermined limit, the clamp circuit reduces the difference between V CCP and V CCR . The voltage regulator 220 provides an output signal which drives the control circuit 230 to generate the signal V CCP-ON 115 .
FIG. 3 (comprising FIGS. 3A and 3B ) is a schematic diagram of the V CCP regulator circuit of FIG. 2 . The clamp circuit 210 comprises a resistor 301 , capacitors 315 and 317 , and diodes 305 , 307 , 309 , 311 , and 313 . A first terminal of the resistor 301 is connected to a regulated voltage V CCR . A second terminal of the resistor 301 is connected a node 319 , to an anode of the diode 305 , to a first terminal of the capacitor 315 , and to a first terminal of the capacitor 317 . A cathode of the diode 305 is connected to an anode of the diode 307 . A cathode of the diode 307 is connected to an anode of the diode 309 . A cathode of the diode 309 is connected to an anode of the diode 311 . A cathode of the diode 311 is connected to an anode of the diode 313 . A cathode of the diode 313 is connected to ground. A second terminal of the capacitor 315 is connected to the regulated voltage V CCR . A second terminal of the capacitor 317 is connected to ground. The node 319 is connected to the gate of a transistor 321 .
The voltage regulator 220 comprises a resistor 337 , capacitors 329 , 331 , and 333 , diodes 323 , 325 , and 327 , and the transistor 321 . An anode of the diode 323 is connected to the pumped supply voltage V CCP , to a first terminal of the capacitor 329 , to a first terminal of the capacitor 331 , and to a first terminal of the capacitor 333 . A cathode of the diode 323 is connected to an anode of the diode 325 and to a second terminal of the capacitor 329 . A cathode of the diode 325 is connected to a drain of the transistor 321 , to a second terminal of the capacitor 331 , and to an anode of the diode 327 . A cathode of the diode 327 is connected to a source of the transistor 321 , to a first terminal of the resistor 337 , to a second terminal of the capacitor 333 , and to a node 335 . A second terminal of the resistor 337 is connected to ground. The node 335 is connected to the control circuit 230 (FIG. 3 B).
The control circuit 230 comprises a resistor 347 , transistors 341 , 343 , 345 , 353 , 355 , 357 , 359 , 363 , 365 , 367 , 369 , 371 , 373 , 375 , and 377 , and inverters 379 , 383 , 385 , and 387 . The gates of the transistors 341 , 343 , 345 , 355 , 357 , and 359 are connected together and are connected to the node 335 from the voltage regulator 220 . A drain of the transistor 341 is connected to the regulated voltage V CCR . A source of the transistor 341 is connected to a drain of the transistor 343 . A source of the transistor 343 is connected to a drain of the transistor 345 . A source of the transistor 343 is connected to a first terminal of the resistor 347 , to a source of the transistor 359 , to a gate of the transistor 365 , and to a gate of the transistor 367 at a node 361 . A second terminal of the resistor 347 is connected to ground.
A drain of the transistor 353 is connected to the regulated voltage V CCR . A source of the transistor 353 is connected to a drain of the transistor 355 . A source of the transistor 355 is connected to a drain of the transistor 357 . A source of the transistor 357 is connected to a drain of the transistor 359 .
A drain of the transistor 363 is connected to the regulated voltage V CCR . A source of the transistor 363 is connected to a drain of the transistor 365 . A source of the transistor 365 is connected a gate of the transistor 373 , to a gate of the transistor 375 , and to a drain of the transistor 367 . A source of the transistor 367 is connected to a drain of the transistor 369 . A source of the transistor 369 is connected to ground. A gate of the transistor 363 is connected to ground. A gate of the transistor 369 is connected to the regulated voltage V CCR .
A drain of the transistor 371 is connected to the regulated voltage V CCR . A source of the transistor 371 is connected to a drain of the transistor 373 . A source of the transistor 373 is connected an input terminal of the inverter 379 and to a drain of the transistor 375 . A source of the transistor 375 is connected to a drain of the transistor 377 . A source of the transistor 377 is connected to ground. A gate of the transistor 371 is connected to ground. A gate of the transistor 377 is connected to the regulated voltage V CCR .
An output terminal of the inverter 379 is connected to the gate of the transistor 353 and to an input terminal of the inverter 383 . An output terminal of the inverter 383 is connected to an input terminal of the inverter 385 . An output terminal of the inverter 385 is connected to an input terminal of the inverter 387 . An output terminal of the inverter 387 provides the output V CCP-ON .
The voltage regulator controls the voltage difference between V CCP and the node 335 . When the voltage at the node 319 is high relative to the drain of the transistor 321 , and therefore the transistor 321 is off, the diodes 323 , 325 , and 327 connect V CCP to the node 335 . Therefore, the voltage across the resistor 337 at the node 335 is approximately 3V T below V CCP , or approximately 2.1 volts below V CCP . As V CCR increases, the clamp circuit 210 turns on the transistor 321 as described below, thereby gradually bypassing the diode 327 . When the transistor 321 is fully turned on, the voltage across the resistor 337 at the node 335 is only two diode drops below V CCP , or approximately 1.4 volts below V CCP . This increases the voltage at the node 335 relative to V CCP , and therefore increases the voltage at the node 335 relative to V CCR . As discussed below, when the voltage at the node 335 is increased relative to V CCR , the control circuit 230 generates an output signal to turn off the charge pump 120 , thereby reducing the value of V CCP .
The capacitors 329 , 331 , and 333 help bring the voltage at the node 335 to a higher level when the voltage of V CCP changes rapidly. When V CCP increases, the voltage at the node 335 rises through the three diodes 323 , 325 , and 327 . The capacitors 329 , 331 , and 333 cause the voltages on the anodes of the three diodes 323 , 325 , and 327 to increase faster than if the capacitors 329 , 331 , and 333 were not present.
The control circuit 230 detects the voltage present across the resistor 337 at the node 335 and then generates the appropriate V CCP-ON output signal necessary to control the V CCP charge pump. As the voltage V CCP increases, the voltage at the node 335 increases. The transistors 341 , 343 , 345 , 355 , 357 , and 359 effectively operate as variable resistors controlled by the voltage on the node 335 . Increasing the voltage at the node 335 turns off the transistors 341 , 343 , 345 , 355 , 357 , and 359 further, thereby increasing the overall resistance of the transistors 341 , 343 , 345 , 355 , 357 , and 359 . Increasing this resistance decreases the voltage across the resistor 347 at the node 361 . When the voltage at the node 361 decreases, the transistor 365 turns on and the transistor 367 turns off. This allows current to flow through the transistor 363 and the transistor 365 to raise the voltage at the gates of the transistors 373 and 375 . The voltage at the gates of the transistors 373 and 375 is greater in magnitude than the voltage at the gates of the transistors 365 and 367 , but remain between V CCR and ground. This increased voltage turns off the transistor 373 and turns on the transistor 375 . With the transistor 375 on, current flows through the transistors 377 and 375 to bring the voltage at the input to the inverter 379 to ground, or low. The transistor 365 and the transistor 375 thus operate as an amplifier to convert the relatively small decrease in voltage at the node 335 to a full voltage swing to ground on the input to the inverter 379 .
With ground on the input to the inverter 379 , the inverter 379 outputs a high voltage, which is used as an input to the inverter 383 and as part of a feedback loop to the gate of the transistor 353 . The inverter 383 outputs a low voltage, which is received at the input of the inverter 385 , which outputs a high voltage. The inverter 385 outputs a high voltage, which is received at the input of the inverter 387 . The inverter 387 then outputs a low voltage, or ground, as the control signal V CCP-ON . The control signal V CCP-ON is an input to the charge pump 120 . Because the control signal V CCP-ON is low, the charge pump 120 turns off to decrease the value of V CCP .
V CCP is also increased in a similar manner. As the voltage of V CCP decreases, the voltage at the node 335 decreases. Decreasing the voltage at the node 335 to a threshold voltage slowly turns on the transistors 341 , 343 , 345 , 355 , 357 , and 359 , thereby decreasing the overall resistance of the transistors 341 , 343 , 345 , 355 , 357 , and 359 . Decreasing this resistance increases the voltage across the resistor 347 at the node 361 . When the voltage at the node 361 increases, the transistor 365 turns off and the transistor 367 turns on. This allows current to flow through the transistor 367 and the transistor 369 to lower the voltage at the gates of the transistors 373 and 375 . This decreased voltage turns on the transistor 373 and turns off the transistor 375 . With the transistor 373 on, current flows through the transistor 371 and 373 to increase the voltage at the input to the inverter to a higher level. The transistor 367 and the transistor 373 thus operate as an amplifier to convert the relatively small increase in voltage at the node 335 to a full voltage swing to V CCR on the input to the inverter 379 .
With V CCR on the input to the inverter 379 , the inverter 379 outputs a low voltage, which is used as an input to the inverter 383 and as part of a feedback loop to the gate of the transistor 353 . The inverter 383 outputs a high voltage, which is received at the input of the inverter 385 , which outputs a low voltage. The inverter 385 outputs a low voltage, which is received at the input of the inverter 387 . The inverter 387 then outputs a high voltage as the control signal V CCP-ON . The control signal V CCP-ON is an input to the charge pump 120 . Because the control signal V CCP-ON is high, the charge pump 120 turns on to increase the value of V CCP .
The feedback signal at the node 381 turns on the transistor 353 when the control signal V CCP-ON is high. This causes the transistors 355 , 357 , and 359 to be connected in parallel with the transistors 341 , 343 , and 345 when the control signal V CCP-ON is active high. When the control signal V CCP-ON is low, the feedback signal at the node 381 turns off the transistor 353 which causes the transistors 341 , 343 , and 345 to be disconnected from the circuit. Because the transistors 355 , 357 , and 359 operate as variable resistors in parallel with the transistors 341 , 343 , and 345 , removing the transistors 355 , 357 , and 359 from the circuit increases the overall resistance of the parallel combination. Thus, as the voltage on the node 335 decreases when the control signal V CCP-ON is low, the resistance of the parallel combination decreases by a smaller amount than if the transistors 355 , 357 , and 359 were in the circuit. Thus, the voltage at the node 335 must go lower with respect to V CCR before the voltage across the resistor 347 at the node 361 changes the state of the transistors 365 and 367 . Therefore, as V CCP decreases, the control circuit 230 generates the control signal V CCP-ON to turn on the charge pump 120 at a voltage lower than the voltage necessary to generate the control signal V CCP-ON to turn off the charge pump 120 . When the control signal V CCP-ON is high to turn on the charge pump 120 , the feedback signal 381 is low. This turns on the transistor 353 , and places the transistors 355 , 357 , and 359 back in parallel with the transistors 341 , 343 , and 345 . Thus, as the voltage on the node 335 increases, the resistance of the parallel combination increases by a smaller amount than when the transistors 355 , 357 , and 359 are disconnected from the circuit. Thus, the voltage at the node 335 must go higher with respect to V CCR before the voltage across the resistor 347 at the node 361 changes the state of the transistors 365 and 367 . The feedback signal 381 therefore alters the voltage necessary to change the state of the transistors 365 and 367 and maintains a relatively constant voltage of V CCP using hysteresis.
As described above, the voltage control circuit 100 maintains the voltage of V CCP by continually switching the charge pump 120 on and off. The control circuit 100 uses hysteresis to maintain a relatively constant voltage of V CCP . For example, if the voltage of V CCR was 3 volts, the desired voltage of V CCP would be approximately 4.5 volts. To achieve this target, the control circuit turns on the charge pump 120 when V CCP reaches 4 volts and turns off the charge pump 120 when V CCP reaches 5 volts.
The maximum value of V CCP can be controlled by manipulating the “trip point” at which the clamp circuit 210 triggers the voltage regulator 220 to activate the charge pump for V CCP . The trip point is controlled by the series of diodes 305 , 307 , 309 , 311 , and 313 . In one embodiment of the invention, the diodes 305 , 307 , 309 , 311 , and 313 are implemented through a combination of PMOS/NMOS transistors. Decreasing the number of diodes in the series limits the voltage at the node 319 , and thereby limits the maximum value of V CCP . However, because a high V CCP is desired for use in the manufacturer's testing, yet a lower V CCP is preferable for user testing, the number of diodes are adjustable in accordance with the present invention.
The clamp circuit 210 operates to limit the voltage at the node 319 , which is the voltage at the gate of the transistor 321 . At low values of V CCR , the diodes 305 , 307 , 309 , 311 , and 313 are off. The diodes 305 , 307 , 309 , 311 , and 313 are long channel devices which turn on gradually. At low values of V CCR , the diodes 305 , 307 , 309 , 311 , and 313 do not conduct. Because V CCP tracks V CCR , the gate-drain voltage of the transistor 321 therefore remains low, keeping the transistor 321 off. As V CCR increases, the diodes 305 , 307 , 309 , 311 , and 313 slowly turn on to clamp the maximum voltage at the node 319 to the total voltage across the five diodes, or 5V T where V T is the voltage drop of one diode (approximately 0.7 volts). This results in a fixed voltage at the node 319 which is connected to the gate of the transistor 321 , while the voltage on the drain of the transistor 321 continues to rise. The magnitude of the gate-drain voltage increases and turns on the transistor 321 . As discussed above, turning on the transistor 321 clamps the voltage V CCP . The capacitors 315 and 319 act as buffers to prevent rapid change of the voltage at the node 319 .
FIG. 4 (comprising FIGS. 4A and 4B ) is a schematic diagram of the V CCP regulator circuit of FIG. 3 including a fuse control 400 to limit the voltage of V CCP . The fuse control 400 comprises fuses 415 , 420 , resistors 418 , 423 , and transistors 425 , 430 . Although the fuse control 400 shows controls for two fuses 415 and 420 , it can be appreciated that any number of fuses and controls may be used depending on the limits of V CCP desired. After manufacturing testing is completed, either or both of the fuses 415 and 420 may be blown. If both fuses 415 and 420 are blown, the diodes 311 and 313 are effectively removed from the circuit. This limits the voltage at the node 319 to 3V T , or 2.1 volts. By limiting the voltage at the node 319 , the gate-drain voltage turns on the transistor 321 at a lower value of V CCR . Therefore, the voltage control circuit 100 turns off the charge pump 120 at a lower value of V CCR , thereby reducing the maximum value of V CCP . If only fuse 420 is blown, only the diode 313 would be removed from the circuit. The voltage at the node 319 would then be limited to 4V T , or 2.8 volts. The 2.8 voltage limit would result in a maximum value of V CCP higher than the 2.1 voltage limit with two fuses blown, yet lower than the 3.5 voltage limit with no fuses blown.
The use of the fuse control 400 allows for flexibility in the design and testing of the semiconductor device. With the fuse control 400 , the clamp circuit 210 may be constructed with many voltage control elements. This allows the supply voltage to reach a higher level before the clamp circuit 210 limits the supply voltage. However, once the circuit is ready to ship, the fuse control 400 bypasses one or more of the voltage control elements, thereby causing the clamp circuit 210 to limit the supply voltage at a lower voltage level. After the fuse control 400 bypasses one or more of the voltage control elements, the remainder of the circuit in FIG. 4 operates in the same manner as the circuit in FIG. 3 .
FIG. 5 is a graph 500 showing the value of V CCP over a range of V CCX both without the fuse control and with the fuse control according to the present invention. The line 520 represents the value of V CCP using the voltage control circuit 100 before the fuse control 400 is activated. The line 515 represents the value of V CCP using the voltage control circuit 100 after the fuse control 400 is activated. The graph 500 is divided into three separate sections. In section A, the semiconductor device is inoperable due to an undervoltage condition. In section B, the semiconductor device is in the specified operating range. In section C, the semiconductor device is in a test mode, such as bum in testing. The graph 500 illustrates that at low values of V CCX , the lines 515 and 520 are the same. This is because the voltage of V CCP is not being limited by the clamp circuit. As the voltage of V CCX increases, the clamp circuit with the fuse control 400 activated begins to limit the voltage of V CCP as shown in line 515 . The clamp circuit 210 keeps the value of V CCP lower for the fuse control 400 activated circuit throughout the upper range of V CCX . Therefore, even if the customer attempts to test the semiconductor device at a high V CCX voltage, the voltage of V CCP remains clamped at a safe level.
Numerous variations and modifications of the invention will become readily apparent to those skilled in the art. Accordingly, the invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The detailed embodiment is to be considered in all respects only as illustrative and not restrictive and the scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope. | A voltage control circuit provides a test supply voltage during manufacturing and testing of a semiconductor device and provides an operational supply voltage after certification of the semiconductor device. The operational supply voltage is lower than the test supply voltage. The voltage control circuit includes a clamp circuit having a plurality of voltage regulation devices, typically diodes. The voltage regulation devices control an output of the clamp circuit. A voltage regulator is electrically coupled to the clamp circuit and generates a first control signal based upon the output of the clamp circuit. A charge pump then receives the control signal from the voltage regulator, and, based on the value of the control signal, the charge pump generates the test supply voltage. At least one bypass device is connected to at least one of the plurality of voltage regulation devices. The bypass device is activated following the certification of the semiconductor device. Once activated, the bypass device bypasses the respective voltage regulation device from the clamp circuit, which limits the output of the clamp circuit. The voltage regulator then generates a second control signal based upon the limited output of the clamp circuit. The second control signal is provided to the charge pump to generate the operational supply voltage. | 6 |
TECHNICAL FIELD
[0001] The present invention relates to a technology for improving a fatigue strength of a cast iron material, in particular, a spherical graphite cast iron.
BACKGROUND ART
[0002] A conventional automobile transmission gear has been manufactured by carburizing and hardening a steel material after the steel material was gear cut. However, there was a problem of deformation of a member due to heat treatment strain.
[0003] By contrast, a spherical graphite cast iron can be readily manufactured. However, it has a disadvantage that it can not be used in an automobile transmission gear because of a low fatigue strength. Accordingly, it is desired for a cast iron material which was not carburized and not hardened so as to have a fatigue strength being the same as that of a carburized and hardened steel material.
[0004] A spherical graphite cast iron has a high mechanical strength in cast irons. As a technology for improving a fatigue strength of a spherical graphite cast iron, there is an austempering treatment applying to a spherical graphite cast iron containing, by weight ratio, 2.0 to 4.0% C, 1.5 to 4.5% Si, 2.0% or less Mn, 0.08% or less P, 0.03% or less S, 0.02 to 0.1% Mg, and 1.8 to 4.0% Cu.
[0005] The bending fatigue strength at 10 7 cycles of a spherical graphite cast iron having such the composition is shown in FIG. 13 . As shown in a rotating bending test curve L of FIG. 13 where a stress (MPa) is shown in a vertical axis and the number of times of repetition of bending is shown in a horizontal axis, even a high tensile cast iron having a tensile strength such high as 1400 MPa only has a fatigue strength of about 200 MPa. This numerical value is comparable to that of a forged article, and the strength of 600 MPa or more being the same level as that of a carburized and hardened steel material is not obtained.
[0006] The fatigue strength of “about 200 MPa” can not be used in an automobile transmission gear.
[0007] As an another prior art, a technology is proposed, according to which a spherical graphite cast iron is cast to improve the fatigue strength thereof by means of adding an additive to a molten metal of a flake graphite cast iron (see Patent Document 1).
[0008] However, such the prior art intends to improve the fatigue strength by improving a casting step and can not improve the fatigue strength of a material after a cast iron material was mechanically machined.
PRIOR ART DOCUMENT
Patent Document
[0009] Patent Document 1: Japanese Patent Application Non-examined Publication No. 2005-8913
SUMMARY OF THE INVENTION
Problem that the Invention is to Solve
[0010] The present invention was proposed in view of problems of above-described prior arts, and intends to provide a method for improving a fatigue strength, which can improve the fatigue strength of a cast iron material, in particular, a spherical graphite cast iron to a value the same as that of a carbon steel that was carburized and hardened.
Means for Solving the Problems
[0011] A method for improving a fatigue strength of a cast iron material of the present invention, contains the steps of
[0012] Performing a first shot peening treatment with shots having the hardness of 600 Hv or more and a particle size (φ) of 0.5 to 0.8 mm (1 step),
[0013] performing a second shot peening treatment with shots having the hardness of 600 Hv or more and a particle size (φ) of 0.1 to 0.3 mm (2 step), and
performing a third shot peening treatment with shots having the hardness of 600 Hv or more and a particle size (φ) of 0.1 mm or less (3 step)
[0015] for each on spherical graphite cast iron on which quenching and tempering heat treatment or austempering heat treatment has been performed and tensile strength made to be 1200 MPa or more, the spherical graphite cast containing the following elements in the following mass percentages: C=2.0-4.0%, Si=1.5-4.5%, Mn=2.0% or less, P=0.08% or less, S=0.03% or less, Mg=0.02-0.1%, and Cu=1.8-4.0% Cu.
[0016] Upon applying the present invention, it is preferred that, after performing the first to third shot peening treatments, a shot peening treatment is performed with shots composed of tin or molybdenum to perform metal lubrication.
Advantages Effects of Invention
[0017] In result of an experiment being carried by the inventor, in a case that the first to third shot peening treatments are performed with respect to a spherical graphite cast iron that contains, by weight ratio, 2.0 to 4.0% C, 1.5 to 4.5% Si, 2.0% or less Mn, 0.08% or less P, 0.03% or less S, 0.02 to 0.1% Mg, and 1.8 to 4.0% Cu, quenching and tempering heat treatment has been performed to the spherical graphite cast iron and that the tensile strength made to be 1200 MPa or more, the fatigue strength of 350 MPa or more can be obtained, which strength is the bending fatigue strength being the same level as that of carburized and hardened steel material.
[0018] Also, in result of an experiment being carried by the inventor, in a case that the first to third shot peening treatments are performed with respect to a spherical graphite cast iron that contains, by weight ratio, 2.0 to 4.0% C, 1.5 to 4.5% Si, 2.0% or less Mn, 0.08% or less P, 0.03% or less S, 0.02 to 0.1% Mg, and 1.8 to 4.0% Cu, an austempering heat treatment has been performed to the spherical graphite cast iron and the tensile strength made to be 1200 MPa or more, the fatigue strength of 350 MPa or more can be obtained, which strength is the bending fatigue strength being the same level as that of carburized and hardened steel material.
[0019] According to the present invention, a compressive residual stress distribution about 600 MPa can be imparted for a range of 100 μm from a surface by performing the first to third shot peening treatments, generations of fine cracks on a surface of a spherical graphite cast iron and development of the cracks are retarded, and therefore, the fatigue strength is improved.
[0020] According to the present invention, by subjecting a predetermined machine process (for example, a gear-cutting process for an automobile transmission gear) to a spherical graphite cast iron, which contains, by weight ratio, 2.0 to 4.0% C, 1.5 to 4.5% Si, 2.0% or less Mn, 0.08% or less P, 0.03% or less S, 0.02 to 0.1% Mg, and 1.8 to 4.0% Cu, quenching and tempering heat treatment or austempering heat treatment has been performed and the tensile strength made to be 1200 MPa or more, and after, by performing the first to third shot peening treatments to the spherical graphite cast iron, the bending fatigue strength being the same level as that of a carburized and hardened steel material can be obtained, without performing a carburizing and hardening treatment.
[0021] Further, since it is not necessary to carry out a heat treatment after machine processing, the heat treatment strain can be prevented.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a drawing showing a procedure of a method for improving a fatigue strength of the present invention.
[0023] FIG. 2 is a drawing showing test results of a tensile test of test samples.
[0024] FIG. 3 is a depth from a material surface-residual stress line chart, which shows a residual stress distribution when each of the first to third shot peening treatments was conducted.
[0025] FIG. 4 is a drawing showing a distribution of compressive residual stresses after the first to third shot peening treatments were performed.
[0026] FIG. 5 is a drawing showing a test piece being used in bending fatigue tests.
[0027] FIG. 6 is a drawing showing test results of rotating bending fatigue tests in Experimental Example 1.
[0028] FIG. 7 is a drawing showing results of Experimental Example 2 as a table.
[0029] FIG. 8 is a drawing showing results of Experimental Example 3 as a table.
[0030] FIG. 9 is a drawing showing results of Experimental Example 4 as a table.
[0031] FIG. 10 is a drawing showing results of Experimental Example 5 as a table.
[0032] FIG. 11 is a drawing showing results of Experimental Example 6 as a table.
[0033] FIG. 12 is a drawing showing results of Experimental Example 7 as a table.
[0034] FIG. 13 is a fatigue strength line chart of a spherical graphite cast iron.
DESCRIPTION OF EMBODIMENTS
[0035] Hereinafter, with reference to accompanying drawings, an embodiment of the present invention will be described.
[0036] At first, with reference to FIG. 1 , a work procedure in an illustrated embodiment will be described.
[0037] In FIG. 1 , a spherical graphite cast iron, which contains 2.0 to 4.0% C, 1.5 to 4.5% Si, 2.0% or less Mn, 0.08% or less P, 0.03% or less S, 0.02 to 0.1% Mg, and 1.8 to 4.0% Cu, by weight ratio, is subjected to quenching and tempering heat treatment or austempering heat treatment so as to make the tensile strength to be 1200 MPa or more (step S 0 ).
[0038] Then, a shot peening treatment is performed (conducted) with shots having hardness of 600 Hv or more and a particle size φ of 0.5 to 0.8 mm (step S 1 : a step for performing a first shot peening treatment: first step).
[0039] Next, a shot peening treatment is performed with shots having hardness of 600 Hv or more and a particle size φ of 0.1 to 0.3 mm (step S 2 : a step for performing a second shot peening treatment: second step).
[0040] Then, a shot peening treatment is performed with shots having hardness of 600 Hv or more and a particle size φ of 0.1 mm or less (step S 3 : a step for performing a third shot peening treatment: third step).
[0041] Thereafter, with tin or molybdenum shots having an appropriate hardness and particle size, a shot peening treatment is performed (step S 4 : a step for performing a fourth shot peening treatment: fourth step).
[0042] According to the step S 4 , on a surface of a workpiece on which the first to third shot peening treatments were performed, metal lubrication can be performed.
[0043] In addition, the step S 4 may be omitted.
[0044] According to said step S 4 , an effect is advantageously imparted that a surface being flattened by the third shot peening treatment is further metal lubricated.
[0045] Said step S 4 is not an indispensable step and can be omitted in order to reduce steps and necessary time period of a whole process.
[0046] From a test sample being performed the first to third shot peening treatments (1 to 3 steps) thereon, a fatigue test sample shown in FIG. 3 was manufactured.
[0047] In an illustrated Embodiment, a shape of a test piece which is entirety shown by a character 12 comprises, for example, in a round bar 3 having an outer diameter of 12 mm, a recess 5 being a grooved in a sectional shape of character V and extending around an entire periphery in a circumference direction. At a bottom 5 a of a recess 5 , a diameter of a round bar 3 is 8 mm. Here, a test piece 12 shown in FIGS. 5( a ) and 5 ( b ) has a shape the same as that of a general test piece.
[0048] With such the test piece 13 , a rotating bending fatigue test was performed.
[0049] As below-mentioned in Experimental Example 1, the fatigue strength of a spherical graphite cast iron to which the shot peening treatments of steps S 1 to S 3 of FIG. 1 were performed has the bending fatigue strength (for example, about 350 MPa) the same as that of a carburized and hardened steel material.
[0050] The inventors have carried out experiments (Experimental Example 1 to Experimental Example 6) such as shown below with a spherical graphite cast iron, which contains 2.0 to 4.0% C, 1.5 to 4.5% Si, 2.0% or less Mn, 0.08% or less P, 0.03% or less S, 0.02 to 0.1% Mg, and 1.8 to 4.0% Cu, by weight ratio.
EXPERIMENTAL EXAMPLE 1
[0051] By performing the quenching and tempering heat treatment to the above-mentioned spherical graphite cast iron, the tensile strength is made to be 1200 MPa or more.
[0052] Results of a tensile test of a test sample, in which samples the quenching and tempering heat treatment applies to the spherical graphite cast iron (the quenching and tempering heat treated spherical graphite cast iron), are shown with a characteristic curve FCD in FIG. 2 .
[0053] In FIG. 2 , a vertical axis indicates a tensile stress (MPa) and a horizontal axis indicates a tensile strain (ε). Three kinds of test pieces No. 1 to No. 3 all have the maximum tensile stresses of 1200 MPa or more. A characteristic curve FCA, that is shown as a reference, shows tensile stress (MPa)-tensile strain (ε) characteristics in a cast iron and the maximum tensile stress was 272.4 MPa.
[0054] Next, with shots having hardness of 600 Hv or more and a particle size (φ) of 0.5 to 0.8 mm, a first shot peening treatment was performed. Results of the first shot peening treatment are shown as a residual stress distribution curve A in FIG. 3 (a residual stress distribution curve after the first shot peening treatment: a characteristic curve having a plot of “□”).
[0055] According to a residual stress distribution curve A, until a depth of 150 μm from a test piece surface (0 μm), a residual stress has a nearly even numerical value of −800 (MPa) while slightly increasing.
[0056] In FIGS. 3 and 4 , a vertical axis shows a numerical value of the residual stress. Therefore, in FIGS. 3 and 4 , in a case that a numerical value of the compressive residual stress is high, it is shown in a lower part (on a side where a negative absolute value is large).
[0057] On a test piece differing to said test piece from which a residual stress distribution curve A in FIG. 3 has been obtained, a second shot peening treatment was performed with shots having a hardness of 600 Hv or more and a shot particle size (φ) of 0.1 to 0.3 mm. Results thereof are shown in FIG. 3 as a residual stress distribution curve B (a residual stress distribution curve after the second shot peening treatment: a characteristic curve having a plot of “O”).
[0058] In the residual stress distribution curve B, in an area (region) until a depth of 50 μm from a test piece surface (0 μm), a compressive residual stress rapidly increases, and in an area in a depth of 50 μm or more, a compressive residual stress slowly increases.
[0059] On a test piece further differing to said test piece from which a residual stress distribution curve A in FIG. 3 has been obtained or differing to said test piece from which a residual stress distribution curve B in FIG. 3 has been obtained, a third shot peening treatment was performed with shots having a hardness of 600 Hv or more and a shot particle size (φ) of 0.1 mm or less. Results thereof are shown in FIG. 3 as a residual stress distribution curve C (a residual stress distribution curve after the third shot peening treatment: a characteristic curve having a plot of “⋄”).
[0060] In a residual stress distribution curve C, in an area until a depth of 25 μm from a test piece surface (0 μm), a compressive residual stress rapidly increases, and in an area deeper from a surface than a depth of 25 μm, a compressive residual stress slowly increases.
[0061] A residual stress distribution thereof is shown in FIG. 4 which shows a result in a case that the first to third shot peening treatments have been performed to the same test piece.
[0062] In FIG. 4 , a residual stress distribution of a test piece before the first to third shot peening treatments is performed is shown with a residual stress distribution curve G.
[0063] On the other hand, a residual stress distribution of a test piece after the first to third shot peening treatments have been performed is shown with a residual stress distribution curve Sa.
[0064] As obvious in FIG. 4 , being compared with a residual stress of a test piece before the first to third shot peening treatments, a residual stress distribution of a test piece after the first to third shot peening treatments increases. Here, a gap (difference) between a residual stress distribution curve G and a residual stress distribution curve Sa corresponds to an increment of a compressive residual stress owing to the first to third shot peening treatments.
[0065] Refering to FIG. 4 , it can be understood that a test piece on which the first to third shot peening treatments have been performed has an increased compressive residual stress entirely in an area from a surface to 150 μm inside, compared with compressive residual stress of a test piece on which the first to third shot peening treatments have not been performed. In FIG. 4 , a gap (difference) between a residual stress distribution curve G and a residual stress distribution curve Sa corresponds to an increment of compressive residual stress.
[0066] A residual stress is such large as 1000 MPa at a surface 0 μm and as about 700 MPa in an area from 25 μm to 100 μm. Also in an area (region) more inside than 100 μm, a test piece on which the first to third shot peening treatments have been performed has an increased compressive residual stress, compared with compressive residual stress of a test piece on which the first to third shot peening treatments have not been performed.
[0067] In Experimental Example 1, the first to third shot peening treatments were performed on the same test piece, a fatigue test piece shown in FIGS. 5( a ) and 5 ( b ) was manufactured from the material (the test piece), and the rotating bending fatigue test (JIS Z 2274) was performed thereon. Results of such the fatigue test are shown in FIG. 6 . In FIG. 6 , a vertical axis indicates (shows) a bending stress (σ: MPa), and a horizontal axis indicates the number of times of repetition (N).
[0068] A mark H in FIG. 6 shows a characteristics curve of the bending fatigue strength of a test piece to which the first to third shot peening treatments were performed in Experimental Example 1.
[0069] It was found in FIG. 6 that a test piece according to Experimental Example 1 has a bending fatigue strength the same as that of a carburizing and quenching steel (about 350 MPa).
[0070] A bending fatigue curve J in FIG. 6 shows a bending fatigue curve of a high tensile cast iron of FCDI 1400 MPa on which a shot peening treatment has not been performed. Said bending fatigue curve J is shown also in FIG. 13 .
[0071] In Experimental Example 1, from results shown in FIG. 6 , it was found that the bending fatigue strength being generally the same as that (about 350 MPa) of a carburized and hardened low carbon steel material can be obtained, by applying quenching and tempering heat treatment to the spherical graphite cast iron, which contains 2.0 to 4.0% C, 1.5 to 4.5% Si, 2.0% or less Mn, 0.08% or less P, 0.03% or less S, 0.02 to 0.1% Mg, and 1.8 to 4.0% Cu, by weight ratio, so as to impart the tensile strength of 1200 MPa or more, and then, performing the first to third shot peening treatments thereto.
[0072] Further, from a compressive residual stress distribution shown in FIG. 3 , it was found that
[0073] when the first shot peening treatment is omitted, a compressive residual stress is decreased in an area deeper by 25 μm or more from a surface decreases, and when the second shot peening treatment is omitted, a compressive residual stress in an area until 25 μm from a surface is decreases.
EXPERIMENTAL EXAMPLE 2
[0074] In Experimental Example 2, a test material that was obtained by applying said spherical graphite cast iron to an austempering heat treatment to be made a tensile strength to be 1200 MPa or more was used.
[0075] With respect to such the test materials, in a manner the same as that of Experimental Example 1, a first shot peening treatment was performed with shots having a hardness of 600 Hv or more and with a shot particle size (φ) of 0.5 to 0.8 mm, to one test material,
[0076] a second shot peening treatment was performed with shots having a hardness of 600 Hv or more and with a shot particle size (φ) of 0.1 to 0.3 mm, to the other test material, and
[0077] a third shot peening treatment has been performed with shots having a hardness of 600 Hv or more and a shot particle size (φ) of 0.1 mm or less, to the further other test material.
[0078] Results of the above-mentioned Experimental Example 2 are the same as that shown in FIG. 3 in Example 1.
[0079] Further, with respect to the same test material, the first to third shot peening treatments have been performed and a compressive residual stress distribution in said test piece was examined. Results of said examination were the same as the results of FIG. 4 in Example 1.
[0080] With a test material on which the first to third shot peening treatments have been performed, a fatigue test piece the same as that of Example 1 was prepared, and a rotating bending fatigue test was carried out.
[0081] Results of such the fatigue test are shown in FIG. 7 . In FIG. 7 , a vertical axis shows a bending stress (σ) and a horizontal axis shows the number of times of repetition (N).
[0082] In FIG. 7 , a fatigue curve K shows a bending fatigue strength of a test piece being performed Experimental Example 2.
[0083] As obvious from results of Experimental Example 2, it was found that when an austempering treatment is performed with respect to a spherical graphite cast iron that contains, by mass percentage, C=2.0 to 4.0%, Si=1.5 to 4.5%, Mn=2.0% or less, P=0.08% or less, S=0.03% or less, Mg=0.02 to 0.1%, and Cu=1.8 to 4.0% to impart a tensile strength of 1200 MPa or more, and the first to third shot peening treatments are performed, a bending fatigue strength being the same as that (about 350 MPa) of a carburizing and quenching steel material can be obtained.
EXPERIMENTAL EXAMPLE 3
[0084] When a first shot peening treatment is performed with respect to a test piece used in Experimental Example 1 (the spherical graphite cast iron, which contains 2.0 to 4.0% C, 1.5 to 4.5% Si, 2.0% or less Mn, 0.08% or less P, 0.03% or less S, 0.02 to 0.1% Mg, and 1.8 to 4.0% Cu, by weight ratio, and was applied quenching and tempering heat treatment thereto), a fatigue test of bending fatigue strength was performed to test pieces, which is manufactured in a manner the same as that of Experimental Example 1, except that shots having a particle size larger than 0.8 mm (particle size: 0.9 mm, 1.0 mm, and 1.1 mm) were used.
[0085] In FIG. 8 , results of the fatigue test when a first shot peening treatment was performed with shots having a particle size of 0.8 mm, 0.9 mm, 1.0 mm or 1.1 mm are shown. In FIG. 8 , “◯” shows that the fatigue strength being the same level as 350 MPa was obtained, and “×” shows that the fatigue strength did not reach about 350 MPa.
[0086] Although in a case that a shot particle size is 0.8 mm, the fatigue strength the same as that (about 600 MPa) of a carburized and hardened steel material was obtained (“◯” in FIG. 8 ), in an other case that a shot particle size is 0.9 mm, 1.0 mm or 1.1 mm, the bending fatigue strength was 350 MPa or less (“×” in FIG. 6 ).
[0087] From FIG. 8 , it was found that in the first shot peening treatment, a shot particle size should be set to 0.8 mm or less.
[0088] When the shot particle size is larger than 0.8 mm in the first shot peening treatment, it is considered that shots are not conveyed by an air flow when shots are blasted off, and therefore, sufficient impacts can not be imparted to the test piece.
EXPERIMENTAL EXAMPLE 4
[0089] In a manner being similar to that of Experimental Example 1, except that shots having a particle size of 0.5 mm or smaller (particle size: 0.5 mm, 0.4 mm, 0.3 mm) were used in a first shot peening treatment, the fatigue test was performed relating to the bending fatigue strength.
[0090] In FIG. 9 , “◯” shows that the fatigue strength being the same level as about 350 MPa was obtained, and “×” shows that the fatigue strength did not reach about 350 MPa.
[0091] As shown in FIG. 9 , in a case that a shot particle size is 0.5 mm, the fatigue strength being the same level as that (about 350 MPa) of a carburized and hardened steel material could be obtained (“◯” of FIG. 9 ), however, in an another case that a shot particle size is 0.4 mm or 0.3 mm, the bending fatigue strength was 350 MPa or smaller (“×” of FIG. 9 ).
[0092] From FIG. 9 , it was found that in the first shot peening treatment, a shot particle size should be set to 0.5 mm or larger.
[0093] It is considered in a case that a shot particle size is smaller than 0.5 mm in the first shot peening treatment, although the compressive stress on a surface side of a steel material becomes larger, the compressive stress inside the steel material becomes smaller.
EXPERIMENTAL EXAMPLE 5
[0094] In a manner similar to that of Experimental Example 1, except that shots having a particle size of 0.3 mm or larger (particle size: 0.3 mm, 0.4 mm, 0.5 mm) were used in a second shot peening treatment, the fatigue test was performed relating to the bending fatigue strength.
[0095] In FIG. 10 , “◯” shows that the fatigue strength being the same level as about 350 MPa was obtained, and “×” shows that the fatigue strength did not reach about 350 MPa.
[0096] As shown in FIG. 10 , in a case that a shot particle size is 0.3 mm, the fatigue strength being the same level as that (about 350 MPa) of a carburized and hardened steel material could be obtained (“◯” of FIG. 8 ), however, in an another case that a particle size is 0.4 mm or 0.5 mm, the bending fatigue strength was 350 MPa or smaller (“×” of FIG. 10 ).
[0097] From results of FIG. 10 , it was found that in the second shot peening treatment, a shot particle size should be set to 0.3 mm or smaller.
[0098] Although the second shot peening treatment is a treatment for improving the compressive residual stress of the outermost surface (a region where a distance from a surface is 50 μm) of a cast iron test piece, it is assumed that a peak of the compressive residual stress is not generated on the most surface and the fatigue strength was not improved, in a case that a shot particle size is larger than 0.3 mm.
EXPERIMENTAL EXAMPLE 6
[0099] In a manner similar to that of Experimental Example 1, except that shots having a particle size of 0.1 mm or smaller (particle size: 0.1 mm, 0.07 mm, 0.01 mm) were used in a second shot peening treatment, the fatigue test was performed relating to the bending fatigue strength.
[0100] In FIG. 11 , “◯” shows that the fatigue strength of about 350 MPa could be obtained, and “×” shows that the fatigue strength did not reach about 350 MPa.
[0101] As shown in FIG. 11 , in a case that a shot particle size is 0.1 mm, the fatigue strength being the same level as that (about 350 MPa) of a carburized and hardened steel material could be obtained (“◯” of FIG. 9 ), however, in an another case that a particle size is 0.07 mm or 0.01 mm, the bending fatigue strength was 350 MPa or smaller (“×” of FIG. 11 ).
[0102] From FIG. 11 , it was found that in the second shot peening treatment, a shot particle size should be set to 0.1 mm or larger.
[0103] It is assumed that when a particle size of shots used in the second shot peening treatment is small, a surface of a cast iron is smoothened merely, the compressive residual stress of the outermost surface of a steel material was not generated, and the fatigue strength could not be improved.
EXPERIMENTAL EXAMPLE 7
[0104] Gears (gears on which the first to third shot peening treatments were performed) Z being manufactured with a test material of Experimental Example 1 and gears Y being manufactured with a test material to which the third shot peening treatment was not applied, were prepared.
[0105] As to gears (gears on which the first to third shot peening treatments were performed) Z being manufactured with a test material of Experimental Example 1, the sliding properties of an engagement surface were good.
[0106] By contrast, as to gears Y being manufactured with a test material to which the third shot peening treatment was not applied, the sliding properties of an engagement surface showed abnormality.
[0107] In more detail, in FIG. 12 , the gears Z were good in touch and sliding properties between engagement gear surfaces and were cleared the predetermined endurance test (shown by “◯” in FIG. 12 ).
[0108] By contrast, the gears Y were not good in touch and sliding properties between engagement gear surfaces, generated fine cracks on a gear surface, and could not clear the predetermined endurance test (shown by “×” in FIG. 12 ).
[0109] From FIG. 12 , it was found that the third shot peening treatment should not be omitted.
[0110] According to the third shot peening treatment, a surface being roughened by the first and second shot peening treatments is smoothened, and an irregularity of a gear surface becomes smaller; accordingly, in fine irregularity, oil stays therein to exert a lubrication operation.
[0111] It is assumed that the test material, to which the third shot peening was not applied, could not exert such the lubrication operation and that sliding abnormality was generated on an engagement surface.
[0112] Illustrated embodiments are merely examples and do not intend to limit a technical range of the present invention.
[0113] For example, illustrated embodiments can be applied to a cum of a valve operating system, con rod, and various kinds of pumps for supplying a gear high pressure oil.
EXPLANATION OF REFERENCE NUMERALS
[0000]
5 ROUND BAR PORTION
6 R CURVE
7 SMALL RADIUS PORTION
13 BENDING TEST PIECE
Y GEAR PREPARED WITH MATERIAL OBTAINED BY OMITTING THIRD STEP
Z GEAR PREPARED WITH MATERIAL AFTER EXPERIMENT 1 | The purpose of the present invention is to provide a method for improving fatigue strength that is capable of improving the fatigue strength of cast iron, specifically spherical graphite cast iron, to the same level as that of carbon steel subjected 10 carburizing and quenching. To this end, this method contains a step for performing first, second and third shot peenings using shot of a prescribed diameter for each on spherical graphite cast iron on which a quenching and tempering heat treatment or austempering heat treatment has been performed and tensile strength made to be 1200 MPa or more, the spherical graphite cast iron containing the following elements in the following mass percentages: C=2.0-4.0%, Si=1.5-4.5%, Mn=2.0% or less, P=O.08% or less, 8=0.03% or less, Mg=0.02-0.1%, and Cu=1.8-4.0%. | 2 |
BACKGROUND OF THE INVENTION
This invention relates generally to semiconductor processing and, more particularly to methods for processing wafers in preparation for wire bonding.
In the manufacture of integrated circuits, a conductive metal pad, such as aluminum copper alloy (ALCu) pad, is typically used allow the electrical connection between active elements of the integrated circuit the external world. More specifically, gold wires or bumps are typically connected to bonding pads formed of this uppermost layer of metal.
In the fabrication of integrated circuits, after the uppermost metal layer is formed, an insulating or dielectric “blanket” layer is deposited over the metal layer. Thereafter, to enable external electrical conuections to the chip, vias are etched through the blanket layer to expose portions of the underlying metal layer. These exposed regions of the metal layer are called “bonding pads.” A clean, residue-free bonding pad surface is desired for optimal bonding of the bond wires to the bonding pads. Otherwise, residues on the bonding pad surface can degrade the reliability of the wire bonds. However, conventional processes for forming bonding pads do not tend to produce clean, residue-free bonding pads.
A conventional process for forming a bonding pad is shown in FIGS. 1-4. FIG. 1 shows a typical bonding pad region 10 of an integrated circuit. The layers that compose the region begin with the uppermost metal layer 12 , typically AL. Above the metal layer, an optional titanium nitride (TiN) or titanium tungsten (TiW) alloy layer 14 is provided for the bonding pad surface. Above the alloy layer, are dialectic layers composed of silicon dioxide 16 and silicon nitride 18 . A resist mask 20 is then deposited above the dielectric layers to facilitate the pad etch process.
FIG. 2 shows the bonding pad region 10 after a typical pad etch. Using a dielectric etcher and gases 22 such as CHF 3 , CF 4 , or SF 6 , the nitride 18 , oxide 16 , and alloy 18 layers are all etched. This etch exposes the uppermost metal layer 12 , thus creating a bonding pad area 24 . However, the etch process leaves fluorine residues 26 on the pad surface 24 , and metallic polymers 28 on the sidewalls. The fluorine residues 26 bond with the underlying AlCu, and cannot be easily removed.
After the pad etch, an asher is typically used to ash the resist 20 . FIG. 3 shows the bonding pad region after an ash treatment. The resist 20 has been removed exposing the upper surface of the nitride 18 dielectric layer. After the resist is ashed, a wet cleaning is performed on the bonding pad to remove residue. The wet cleaning, however, cannot remove all the etch process residue 26 , since much of the fluorine residue has bonded to the bonding pad. In addition, the metallic polymers 28 are not soluble in the solvents normally used, thus they remain on the sidewall after wet cleaning.
If the wafer is allowed to sit for any amount of time, or if it collects any kind of moisture, the fluorine residue 26 in the bond pad 24 will migrate to the surface and form a fluorine crystal 30 . This crystal prevents a reliable bond with the bond pad surface. Thus, a bond wire 32 may break away from the bond pad 24 after bonding, or form a high resistance connection to the bonding pad.
Bonding pad failure reduces the yield of functional integrated circuits, and thus increases their cost. Further, poor bonding pad connections reduce the reliability of the integrated circuits.
In view of the above, it is apparent that an improved process for creating a clean, reliable bonding pad surfaces is required. Such a process should not leave substantial imbedded residue in the bonding pad surface. In addition, it should meet the demands of high volume manufacturing by not requiring undue time to execute, or additional machinery.
SUMMARY OF THE INVENTION
The present invention meets the aforementioned requirements by providing a process that treats a bond pad surface with a CF 4 and water vapor combination. This volatizes the fluorine from the bond pad surface and softens the metallic polymers adhering to the sidewalls. In the process, hydrogen from the water vapor breaks up and couples to the fluorine creating HF, which is volatile in a plasma. As a result, the fluorine is removed from the bond pad surface before it has a chance to crystallize, resulting in a clean bond pad surface. The invention produces clean, reliable bonding pad surfaces resulting in drastically reduced bond wire failure. Furthermore, it does not require undue time to perform and requires no additional machinery.
One aspect of the present invention teaches a method for treating a bond pad surface with a CF 4 and water vapor combination. During the process, the CF 4 and water vapor are ionized. The ionization causes the hydrogen from the ionized water to combine with the fluorine residue on the bonding pad surface, creating a volatile HF vapor. In addition, fluorine from the ionized CF 4 exchanges with metal from the metallic polymer residue causing the polymers to soften. The process then includes ashing the resist layer, followed by stripping the wafer in a liquid solvent to remove contaminants including the metallic polymers. This process prevents fluorine crystallization and provides a clean bond pad surface.
Another aspect of the present invention teaches a system for cleaning integrated circuit bonding pads including a plasma asher, an organic stripper, and back end processors for completing the chips. The asher must be capable of treating an integrated circuit with a CF 4 and water vapor combination to volatize the fluorine and soften the metallic polymers.
These and other advantages of the present invention will become apparent to those skilled in the art upon a reading of the following descriptions and study of the various figures of the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of a prior art bonding pad region;
FIG. 2 is a cross-sectional view of a prior art bonding pad region after a pad etch;
FIG. 3 is a cross-sectional view of a prior art bonding pad region after ashing;
FIG. 4 is a flow chart illustrating one method for producing clean bonding pads in accordance with the present invention;
FIG. 5 is a cross-sectional view of a bonding pad region of the present invention after etching the dielectric/alloy layers and treating the bond pad with a CF 4 /water vapor combination;
FIG. 6 is a cross-sectional view of the bonding pad region of the present invention after bond wire attachment; and
FIG. 7 is an illustration of a system for producing clean bonding pads in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1-3 were described with reference to the prior art. With reference to FIG. 4, a method 100 for producing a clean bonding pad in accordance with one aspect of the present invention will now be described. In the initial operation 102 , an opening is formed in the dielectric and alloy layers. For example, an opening can be formed through nitride 18 , oxide 16 , and TiN (or TiW) 14 layers of the wafer (see FIG. 5 ). The etch process is usually accomplished in a dielectric etcher using a gas 22 such as CF 4 . However, other gases such as CHF 3 , SF 6 , or C 2 F 6 , are suitable for use in the etching process.
Operation 102 generally leaves residues such as TiN, TiF x , TiO x ,F y , C, F, or CF x , on the AlCu surface, which should be removed before the F in the residue migrates to the surface and crystallizes, thus degrading the reliability of the wire bonds. In addition, this operation also leaves polymers 28 on the sidewalls caused mostly by sputtering from the surface of the materials as they are being reacted. For example, the TiN or TiW gets sputtered into the polymer 28 giving the polymer a metallic component, thus making it hard to strip. The present invention uses a CF 4 /water vapor combination to soften this metallc polymer and remove the fluorine residue, as discussed below in operation 104 .
In the next operation 104 , the bonding pad is treated with a CF 4 , water vapor, and possibly a diluent, such as nitrogen, combination in a microwave or RIE plasma. This combination volatizes the fluorine in the bond pad surface and softens the metallic polymers adhering to the sidewalls. In the process, the water vapor breaks up and the hydrogen from the water vapor couples to the fluorine residue 26 creating HF, which is volatile in the plasma. Thus, the fluorine is removed from the ALCu before it has a chance to crystallize on the bonding pad surface 24 . In addition, fluorine from the CF 4 exchanges with the titanium in the metallic polymer 28 making the polymer more soluble for the organic strip operation which follows. This operation can be performed on a microwave asher such the Lam Research Corp. microwave asher. Another suitable device with which to perform this operation is the ash chamber of the Lam Research Corp. 9600SE metal etcher. Using this tool, 650 sccm H 2 O is combined with 200sccm CF 4 . The device is set at: 1000 W, 1.2 torr, 200° C. for 30 sec. Note, this is just one example of a tool that may be used for this operation. Other tools are available that may be used to perform the same process.
In the next operation 106 , an oxygen plasma combined with varying ratios of water vapor is used to ash the resist mask 20 . The oxygen helps to increase photoresist ash rate, while the water vapor liberates the attached fluorine and any free fluorine remaining.
Finally, in operation 108 , an organic resist stripper is applied to remove any remaining polymer. Particularly, C compounds remaining on the ALCu surface and sidewalls are removed by this process. However, this operation also helps remove any remaining polymer.
FIG. 5 is cross-sectional view of the bonding pad region 10 of the present invention after operation 104 of method 100 is applied. The bond pad surface 24 is substantially free of fluorine residue 26 . The removal of the fluorine from the surface prevents fluorine crystallization should the wafer be allowed to sit for a length of time, or collect any moisture. In addition, the sidewalls are free from any metallic polymers 28 , since the fluorine from the CF 4 exchanges with the titanium in the metallic polymer 28 . Therefore, any polymer remaining after operation 104 will be devoid of a metallic component, and thus more soluble in an organic strip.
FIG. 6 is a cross-sectional view of the bonding pad region of the present invention after method 100 is completed and a bond wire attached. The resist has been ashed and an organic strip has been applied, removing any remaining polymers. A gold bond wire has also been attached to the bonding pad surface 24 . Since the bonding pad surface 24 is free of any fluorine crystallization, a reliable bond wire 32 attachment can be achieved.
In addition to increasing bond wire reliability, the present invention also increases the amount of storage time for the wafer. Prior to the present invention, if the wafer was allowed to sit for a length of time, or was allowed to collect any kind of moisture, the fluorine trapped in the bonding pad surfaces 24 would migrate to the surface and form a fluorine crystal. This crystal structure would prevent reliable wire bonding to the chip. The present invention avoids this by removing fluorine residue remaining on the bonding pad surface. This substantially eliminates fluorine crystallization on the bonding pad surface caused by long storage times or moisture, thus allowing for longer storage periods and greatly improved wire bond reliability.
FIG. 7 illustrates a system 200 for producing clean bonding pads in accordance with one aspect of the present invention. The system begins with a wafer 202 ready to receive bonding pads. In the initial part 204 of the system, a plasma etcher is used to etch the dielectric, nitride 18 and oxide 16 , and alloy layers, TiN (or TiW) 14 , to create the bond pad. The etch is usually done using a gas 22 such as CF 4 . However, other gases such as CHF 3 , SF 6 , or C 2 ,F 6 , are suitable for use in the etcher. This operation generally leaves residues such as TiN, TiF x , TiO x F y , C, F, or CF x on the AlCu surface, which should be removed before the F in the residue migrates to the surface and crystallizes, thus degrading the reliability of the wire bonds. In addition, this operation also leaves polymers 28 on the sidewalls caused mostly by sputtering from the surface of the materials as they are being reacted. The present invention uses a CF 4 /water vapor combination to soften the metallc polymer and remove the fluorine residue, as discussed below.
In the next part of the system 208 , the wafer is placed in a plasma asher. The asher is used to treat the bonding pad with a CF 4 , water vapor, and possibly a diluent, such as nitrogen, combination in a microwave or RIE plasma. This combination volatizes the fluorine in the bond pad surface and softens the metallic polymers adhering to the sidewalls. The water vapor breaks up and the hydrogen from the water vapor couples to the fluorine residue 26 creating HF, which is volatile in the plasma. Thus, the fluorine is removed from the ALCu before it has a chance to crystallize on the bonding pad surface 24 . In addition, fluorine from the CF 4 exchanges with the titanium in the metallic polymer 28 making the polymer more soluble for the organic stripper. The asher used in this part of the system may be a microwave asher such the Lam Research Corp. microwave asher. Another suitable device is the ash chamber of the Lam Research Corp. 9600SE metal etcher. Using this tool, 650 sccm H 2 O is combined with 200 sccm CF 4 . The device is set at: 1000 W, 1.2 torr, 200° C. for 30 sec. Note, this is just one example of a tool that may be used in this system. Other tools are available that may also be used in the system of the present invention.
The asher is then used to apply an oxygen plasma combined with varying ratios of water vapor to ash the resist mask 20 . The oxygen helps to increase photoresist ash rate, while the water vapor liberates the attached fluorine or any free fluorine remaining.
In the next part of the system 210 , an organic resist stripper is used to remove any remaining polymer. Particularly, C compounds remaining on the ALCu surface and sidewalls are removed by this process. However, this operation also helps remove any remaining polymer.
In the next part of the system 212 , gold bond wires are attached to the bonding pads. The gold wires, or bumps, are connected to the ALCu surface of the bonding pad 24 . Bonding is most successful when a clean, residue-free AlCu surface is available for bonding. The wire bond will be degraded by fluorine crystal and other residues on the bonding pad surface. The present invention increases bond wire reliability by producing clean, residue-free bonding pads. Wafers resulting from the system of the present invention may also be stored longer and with less thought of preventing moister than has been previously possible, since crystallization is substantially prevented by the removal of the fluorine from the bonding pad surface as discussed above.
Finally, in the final part of the system 213 , back end processors are used to complete the chips 214 and the chips are packaged.
The results of the system are integrated circuits having reliable bonding wire attachments resulting in drastically reduced bond wire failure. Furthermore, the system does not require undue time to perform and requires no additional machinery. As previously stated, existing machinery can be used in the system, such as the Lam Research Corp. microwave asher, or the ash chamber of the Lam Research Corp. metal etcher.
While this invention has been described in terms of several preferred embodiments, it is contemplated that alternatives, modifications, permutations and equivalents thereof will become apparent to those skilled in the art upon a reading of the specification and study of the drawings. It is therefore intended that the following appended claims include all such alternatives, modifications, permutations and equivalents as fall within the true spirit and scope of the present invention. | A method for cleaning bonding pads on a semiconductor device, as disclosed herein, includes treating the bonding pads with a CF 4 and water vapor combination. In the process, the water vapor breaks up and the hydrogen from the water vapor couples to fluorine residue on the bonding pad surface creating a volatile HF vapor. In addition, fluorine from the CF 4 exchanges with the titanium in the metallic polymer residue making the polymer more soluble for the organic strip operation which follows. Next, the resist is ashed and then an organic resist stripper is applied to the bonding pad area, thereby creating a clean bonding pad surface. Thereafter, a reliable bond wire connection can be made to the bonding pad. | 7 |
CROSS REFERENCE TO RELATED APPLICATION
This application claims priority of the filing date of provisional application Ser. No. 61/374,669 filed on Aug. 18, 2010.
RIGHTS OF THE GOVERNMENT
The invention described herein may be manufactured and used by or for the Government of the United States for all governmental purposes without the payment of any royalty thereon.
FIELD OF THE INVENTION
This invention relates to synthesis methods and applications for the production and use of organic/inorganic hybrid polyhedral oligomeric silsesquioxane (POSS) nanomaterials.
BACKGROUND OF THE INVENTION
The dispersion of nanoscopic particles in host polymers has resulted in well-documented improvements in various properties, such as thermo-oxidative stability, response to mechanical load, thermal expansion, space survivability, abrasion resistance, moisture uptake, electrical characteristics, and other surface-related properties. As a result, the application of nanotechnology has enabled an expansion in the end-use envelope of many organic materials. Nanoparticles classified as polyhedral oligomeric silsesquioxanes, or POSS, have proven to be a particularly effective class of additives due to their inherent size, shape, rigidity, and versatility in function. The ability to chemically tailor POSS through synthetic manipulation over its organic periphery offers a unique design tool for controlling particle affinity and resultant dispersion in host materials. The number of peripheral substituents is dependent on the size of the silsesquioxane cage itself, or more precisely, the number of silicon atoms contained within the cage. The nature of those substituents may be depends on the limitations defined by state-of-the-art POSS synthesis methods. There are advantages and disadvantages in the choice of an inert or reactive periphery. In general, inert functionalities do not require an adjustment of polymerization stoichiometry or impose complications arising from differences in the reaction kinetics amongst the involved chemical species; however, inert functionalities provide limited control in the formation of desired material morphologies and increased possibility for nanoparticle flux to a more desired energy state over time that may result in a possible degradation of properties during such a process. Reactive moieties, on the other hand, allow for more precise control over copolymer architecture and impede nanoparticle migration over time (due to covalent attachment to the host); however, reactive moieties stoichiometric balance that is often hindered by steric restraints. A review of the current state of inert and reactive POSS technologies may be found in Fina, A. et al., Journal of Materials Chemistry 2010, 20(42), 9297-9305. Overall, selection of the POSS periphery should be based on the structure of the polymer that is intended to be modified and the desired end-use properties.
To date, an array of POSS molecules have been developed for a variety of applications. While POSS is useful as a commercial additive, there are currently some limitations in its utility. The limitations are especially true in the modification of high temperature polymers, due to a general weakness in the thermal stability of organic peripheries with C—C bonds having dissociation energies in the close proximity of 80 kcal/mol. Currently, the most thermally robust versions of POSS have cages functionalized with complete inert aromaticity. Examples include Octaphenyl™ and Dodecaphenyl™ POSS, which feature pure phenyl moieties comprised of C═C bonds having dissociation energies of approximately 150 kcal/mol. Unfortunately, such molecules demonstrate a propensity to crystallize to the extent that their assembled aggregation is unaffected by shear forces imposed by conventional polymer blending and compounding methods. Crystallization is also to the extent that the exemplary POSS cages degrade during the melting process, both characteristics preventing effective dispersion into host materials. From a structural perspective, POSS molecules readily crystallize due to the rigid and regular nature of the silsesquioxane cage itself. This propensity for crystallization has been shown to be disrupted through the design and synthesis of a heterogeneous organic periphery, which is described in Moore et al., Journal of Organometallic Chemistry 2011, 696(13), 2676-2680. The achievement of a balance between good thermal stability and dispersability lies in molecular design.
To maximize the full benefits of POSS incorporation into polymer hosts, such as in terms of the delivered composite properties, the POSS molecules design requires consideration of molecular assembly during incorporation into a polymer host. For POSS molecules possessing a reactive or partially reactive periphery, geometric forethought of the attachment route with a polymer host network is necessary. For example, POSS may be incorporated through copolymerization by strategic placement of the silsesquioxane cage in the main chain (“bead-on-a-string”) of a growing polymer chain or network, as described in U.S. Pat. No. 6,767,930, issued To Svejda et al. in 2004, or conversely, in a pendant, or dangling-type conformation, such as is described in Wright et al., Macromolecules 2006, 39(14), 4710-4718. The resulting architectures often yield a marked difference in morphology and as a result, in delivered properties.
In terms of imparting reactive functionality to POSS, amine groups offer the most versatility due to their compatibility with many types of polymers, viz. epoxies, cyanate esters, and polyimides (both thermoplastic and thermosetting in nature). Twelve varieties of amino-containing POSS molecules are commercially available, however, all but one of those compounds contain peripheries comprised of thermally labile chemical groups, i.e., any combinations of isobutyl, isooctyl, cyclohexyl, ammonium, aminoethyl, and aminopropyl groups. POSS molecules have been used to modify various polymers, which are the subject of various patents. In the high temperature polymer area, for example, polyimides have been modified with aminopropylisobutyl POSS in Poe, et al. U.S. Application Publication Nos. 2009/0069508 (2008) and 2010/0063244 (2009). These types of moieties, in general, pose a thermal and solubility mismatch with polymers considered to be high temperature (largely aromatic). Disassociation of the POSS organic periphery can produce free radicals that may react with any polymer in the immediate vicinity, thus causing chain scission and property weakening. The sole commercial compound that possesses a thermally stable, homogeneous aniline periphery has the drawback of possessing a high density of reactive groups. When reactively is incorporated into a polymer, this characteristic generally contributes to either the formation of an over-crosslinked network resulting in material embrittlement or incomplete amine conversion (due to steric barriers resulting in sites that exhibit an affinity to water, which are deleterious toward material aging manifested in thermo-mechanical properties). Therefore, there exists a significant need for the development of new, thermally stabile, amino-functionalized POSS compounds with a lower concentration of reactive groups. Such molecules would be beneficial in the design and control of polymeric architectures for the purposes of maximizing delivered properties, especially at elevated temperatures. Further utility of the embodied aniline POSS compounds is readily derived from chemical reaction of their amine groups with anhydride compounds to form imide-type moieties with other types of reactive end-groups, notably phenylethynyl phthalic anhydride (PEPA) (a crosslinkable group found on the ends of many high performance thermosetting oligomeric compounds). Crosslinking proceeds during consumption of the ethynyl group through cyclotrimerization to form a thermally and mechanically robust aromatic junction.
The nomenclature for silicon atoms was originally developed to distinguish silicon monomers and polymers. A silane (M) group consists of three organic groups and one oxygen atom bound to a central silicon atom. A siloxane (D) group consists of two organic groups and two oxygen atoms bound to the central silicon atom. When one organic group and three oxygen atoms bound to a central silicon atom, the group is referred to as a silsesquioxane (T) group. A silicate (Q) group consists of four oxygen atoms bound to the central silicon atom, which is not bound to any organic groups. The structure of each group is illustrated below. This method allows the simplified description of various structures.
SUMMARY OF THE INVENTION
The present invention describes previously unreported versions of POSS mono- and dianilines that feature completely aromatic peripheries for the purpose of matching the thermal and chemical capabilities of the POSS compound with high performance polymeric materials. Incorporation of these POSS mono- or dianilines into polymer hosts occurs through chemical reaction of amine moieties of the POSS compound with a variety of functionalities, including epoxies, anhydrides, and cyanate esters. The amine groups may also be further reacted with phenylethynyl phthalic anhydride (PEPA) to yield POSS monomers useful as drop-in additives for high temperature thermosets, also possessing PEPA in their chemical structure. Resulting POSS-containing polymers generally exhibit improved processing and delivered properties.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is NMR spectrum of bis(para-aniline, methyl)silyloxy-octaphenylsilsesquioxane (“bead-type” POSS).
FIG. 2 is chemical structures of monomers and resultant oligoimides resulting from systematic modification of the condensation oligomer 6FDA-ODA-PEPA by substitution of ODA with “bead-type” POSS.
FIGS. 3A-3D exhibit representations of the chemical structures of the various conformations that “bead-type” POSS dianilines can adopt, including: trans-bis(para-aniline, methyl)silyloxy-octaphenylsilsesquioxane in FIG. 3A , cis-bis(para-aniline, methyl)silyloxy-octaphenylsilsesquioxane in FIG. 3B , trans-bis(meta-aniline, methyl)silyloxy-octaphenylsilsesquioxane in FIG. 3C , and cis-bis(meta-aniline, methyl)silyloxy-octaphenylsilsesquioxane in FIG. 3D .
FIG. 4 illustrates chemical structures of heptaphenyl-monoaniline-T8 POSS with amine functionality either in the para or meta position relative to phenyl group attachment to the Si atom.
FIG. 5 illustrates the chemical structure for heptaphenyl-monoaniline-T8 POSS reacted with phenylethynyl phthalic anhydride (PEPA) to form phenylethynyl phthalimide (PEPI), wherein the PEPI functionality can either be in the para or meta position relative to phenyl group attachment to the Si atom.
FIG. 6 is an example of the reaction product between a “bead-type” POSS isomer and PEPA.
FIG. 7 is an example of silicon atom nomenclature, describing M-, D-, T-, and Q-type silicon atoms.
DETAILED DESCRIPTION OF THE INVENTION
This invention describes syntheses and applications of novel polyhedral oligomeric silsesquioxane (POSS) anilines and anhydride-modified derivatives thereof. The POSS compounds exhibit complete aromaticity in their heterogeneous organic peripheries. The POSS anilines may include: (1.) a “bead-type” silsesquioxane diamine possessing 10 silicon atoms and 14 oxygen atoms, wherein 8 of the silicon atoms are considered T silicon atoms (covalently attached to 3 oxygen atoms) and two of the silicon atoms are D silicon atoms attached to 2 oxygen atoms with the anilines placed in the meta position relative to the attachment of the phenyl groups to the D silicon atoms; (2.) heteroleptically phenyl POSS T8 monoaniline isomers, where the amine group is attached in the para or meta position relative to the attachment of the phenyl group to a T silicon atom; (3.) “bead-type” silsesquioxanes with the aniline groups either in the para or meta position relative to the D silicon atoms, where the amine groups are reacted with phenylethynyl phthalic anhydride (PEPA) to form phenylethynyl phthalic imide (PEPI) POSS molecules; and (4.) the POSS T8 monoaniline isomers, or any mixture thereof, reacted with PEPA to form T8 mono-functional T8 PEPI. Other embodiments are directed to a method of synthesizing an existing double-decker (T8D2) silsesquioxane diamine with the dianiline groups in the para position relative to the D silicon atoms. The uniqueness of the disclosed materials is their design for controlled incorporation into polymers that can withstand continuous service at 200-350° C. in an oxygen-rich environment (that is, high temperature polymers). In terms of chemical architecture, the POSS compounds of the present invention feature silsesquioxane cages surrounded by only phenyl and aniline moieties. POSS cages having aniline moieties are equipped for facile attachment to host systems that accept amines through chemical reaction. The reactions include, for example, polyimides through linear copolymerization and epoxies where the amines can participate in network formation through crosslinking. Complete peripheral aromaticity and a lack of thermally labile groups enable exceptional thermal stability for POSS anilines and good solubility (high optical clarity) in high temperature polymers.
Copolymerization of these types of POSS molecules with thermoplastic or thermosetting polymer systems that accept amines during chemical reaction or ethynyl groups through cyclotrimerization, viz. monomers, oligomers, or polymers having epoxide groups, anhydride groups, cyanate ester groups, or ethynyl groups, are anticipated to improve processability, short- and long-term thermo-oxidative stability, abrasion resistance, mechanical properties such as toughness, creep, coefficient of thermal expansion and tensile strength, solvent resistance, dielectric properties, and reductions in thermal expansion, moisture uptake, flammability and heat of combustion, and hydrophobicity.
EXAMPLES
1. Synthesis of Phenyl 7 POSS Monoaniline
Synthesis of monoamine precursor, p-Cl 3 Si[PhN(TMS) 2 ]: A solution of 4-Bromo-N,N-bis(trimethylsilyl)aniline (9.48 g, 30 mmol) in 25 mL of anhydrous THF is taken in an addition funnel and slowly added to a stirring mixture of Mg (0.912 g, 38 mmol) and anhydrous THF initiated with a crystal of I 2 and a drop of 4-bromo-N,N-bis(trimethylsilyl)aniline. The reaction is allowed to stir overnight at ambient temperature, cannulated to a 250 mL round bottomed flask, and very slowly added to a stirring mixture of THF (10 mL) and silicon tetrachloride (5.35 g, 31.5 mmol). This is allowed to stir overnight. The solvent is removed, in vacuo, from the reaction mixture and dry hexane added to extract the product by filtration through celite. After removing all volatiles under a dynamic vacuum, the residual yellow colored filtrate is transferred to a 25 mL flask and distilled under dynamic vacuum to give phenyl-bis(trimethylsilyl)trichlorolsilane, as a colorless, very viscous liquid in 90% yield. 1 H NMR (CDCl 3 ) 0.136 ppm (s, 18H, NSiCH 3 ), 7.08 ppm (m, 4H), 7.73 ppm (m, 4H). 29 Si NMR (CDCl 3 ) 5.81 ppm, −0.475 ppm (ratio=2:1)
Synthesis of POSS monoamine: a solution of phenyl-bis(trimethylsilyl)trichlorolsilane precursor (0.89 g, 2.4 mmol), in 5 mL dry ether is added very slowly to a stirring solution of trisilanolphenyl-POSS, Ph 7 Si 7 O 9 (OH) 3 (2.06 g, 2.2 mmol) in 10 mL dry ether and 5 mL anhydrous THF. To this is very slowly added a solution of distilled triethylamine in dry ether (0.6966 g, 6.90 mmol). This is left stirring over night. The solution is filtered to remove NEt 3 . HCl precipitates and rotary evaporated to slurry. The slurry is precipitated fully in 150 mL reagent grade methanol acidified with glacial acetic acid to give POSS monoamine monomer in 60% yield. 29 Si NMR (CD 2 Cl 2 ) −76.99 ppm, −78.34 ppm, −78.50 ppm (ratio=1:4:3).
2. Synthesis of Phenyl 7 POSS Mono-phenylethynyl Phthalic Imide
In a 50 mL round bottom flask, a solution of PEPA (0.246 g, 1 mmol) in 35 mL toluene is added to a stirring solution of POSS phenylamine (1.05 g, 1 mmol) in 5 mL dimethylacetamide (DMAC). This is attached to a reverse Dean Stark apparatus, which is dried in an oven, evacuated, and backfilled with GN2 prior to use. The entire set up is equipped with a condenser and a thermometer. The stirring reaction mixture is heated in an oil bath at 1500° C. for 6 hr and allowed to cool to room temperature. White precipates obtained at the bottom of the reaction flask are filtered, washed with anhydrous diethyl ether, and air dried under nitrogen for 6 hr. These are further dried under vacuum at 1200° C. for 24 hr. 29Si NMR (CDCl 3 ) −78.07 ppm, −78.16 ppm, −78.67 ppm (ratio=3:4:1).
3. Synthesis of Bis(Meta-aniline, Methyl)Silyloxy-octaphenylsilsesquioxane (“Bead-type” POSS Dianiline)
Under a nitrogen atmosphere, in a 50 mL round-bottomed flask phenylPOSS-tetrol, Phenyl 8 Si 8 O 10 (OH 4 ), (2.00 g, 1.87 mmol) is suspended in 10 mL of anhydrous THF. To this stirred suspension, a solution of 3-[bis(N,N-trimethylsilyl)phenylamino]methyldichlorosilane (1.376 g, 3.93 mmol) and NEt 3 (0.776 g, 7.67 mmol) in THF (10 mL) is slowly added in a drop-wise manner. After 30 min, the solution is filtered to remove NEt 3 HCl (957 mg, 6.95 mmol, 93% theoretical) and the solvent is removed under vacuum. Approximately 1 mL of diethylether is added to the product followed by 20 mL of MeOH to make a well-stirred suspension of white-colored intermediate. The trimethylsilyl groups are hydrolyzed by the addition of 1 drop of concentrated acetic acid and 1 hr of stirring. The product is isolated by filtration and dried under a nitrogen stream to give a white powder in 84% yield (2.097 g, 1.57 mmol). 1 H NMR (CDCl 3 , δ) 7.62-6.99 ppm (m, 44H), 6.74 ppm (m, 4H), 3.3 ppm (broad s, 4H, NH2), 0.58 ppm (s, 6H). 29 Si NMR (CDCl 3 ) −30.5 ppm, −78.4 ppm, −79.4 ppm, −79.6 ppm, −79.8 ppm.
4. Synthesis of Bis(Para-aniline, Methyl)Silyloxy-octaphenylsilsesquioxane (“Bead-type” POSS Dianiline)
Synthesis of 4-[Bis(N, N-trimethylsilyl)phenylaminio]methyldichlorosilane precursor: under a nitrogen atmosphere a solution of 4-bromo-N, N-bis(trimethylsilyl)aniline (9.48 g, 30 mmol) in 25 mL of anhydrous THF was placed in an addition funnel and slowly added to a stirring mixture of Mg (0.912 g, 38 mmol) and anhydrous THF, already initiated with a small crystal of I 2 and a drop of 4-bromo-N,N-bis(trimethylsilyl)aniline. The reaction was allowed to stir overnight at ambient temperature, then slowly cannulated into a 250 mL round-bottomed flask containing a stirring mixture of THF (10 mL) and methyltrichlorosilane (4.485 g, 30 mmol). This was allowed to stir overnight. The solvent was removed, in vacuo, from the reaction mixture and dry hexane added to extract the product by filtration through celite. After removing all volatiles under vacuum at room temperature, the remaining yellow-colored filtrate was transferred to a 25 mL flask. This was distilled at 89° C. under dynamic vacuum using a Kugelrohr apparatus to give the product as a colorless liquid in 87% yield (9.15 g, 26.1 mmol). 1 H NMR (CDCl 3 ) 0.13 ppm (s, 18H, NSiCH3), 1.06 ppm (s, 3H, SiCH3), 7.03 ppm (m, 2H), 7.61 ppm (m, 2H). 29 Si NMR (CDCl 3 , δ) 5.2 ppm, 18.9 ppm (ratio=2:1).
Synthesis of Bis(para-aniline, methyl)silyloxy-octaphenylsilsesquioxane: under a nitrogen atmosphere, in a 50 mL round-bottomed flask phenyl POSS-tetrol, Phenyl 8 Si 8 O 10 (OH 4 ), (2.00 g, 1.87 mmol) was suspended in 10 mL of anhydrous THF. To this stirred suspension, a solution of 4-[bis(N, N-trimethylsilyl)phenylaminio]methyldichlorosilane (1.376 g, 3.93 mmol) and NEt 3 (0.776 g, 7.67 mmol) in THF (10 mL) was slowly added in a drop-wise manner. After 30 min, the solution was filtered to remove NEt 3 HCl (974 mg, 7.08 mmol, 95% theoretical) and the solvent was removed under vacuum. Approximately 1 mL of diethylether was added to the product followed by 20 mL of MeOH to make a well-stirred suspension of white-colored intermediate. The trimethylsilyl groups were hydrolyzed by the addition of 1 drop of concentrated acetic acid and 1 hr of stirring. The product was isolated by filtration and dried under a nitrogen stream to give a white powder in 77% yield (1.922 g, 1.44 mmol). 1 H NMR (CDCl 3 , δ) 7.83-7.10 ppm (m, 44H), 6.60 ppm (m, 4H), 3.3 ppm (broad s, 4H, NH2), 0.11 ppm (s, 6H). 29 Si NMR (CDCl3) −29.7 ppm, −78.2 ppm, −79.1 ppm, −79.3 ppm, −79.4 ppm (reference spectrum in FIG. 1 ).
5. Application of POSS Monoaniline for the Purposes of Thermosetting Polymer Modification
To modify a conventional epoxy resin/aminated hardener system with POSS monoaniline, a mixture of amines is employed to cure the epoxy adhesive. In the specific example of DER 331 epoxy, having an epoxide equivalent weight of 189, cured with 4-4′-dimanodiphenyl sulfone (DDS) possessing an amine H equivalent weight of 64, modified with 5% POSS monoaniline to 95% DDS in the amine mixture:
Amine
H
eq
·
wt
·
POSS
=
544
2
=
272
phr
Amine
=
272
×
100
189
×
0.05
+
64
×
100
189
×
0.95
=
39.37
phr POSS monoaniline amine=7.2
phr DDS=32.2
To 100 g DER 331 epoxy, 39.37 g DDS, and 7.2 g POSS monoaniline are added and are homogenized with or without the use of a common solvent. If solvent is used, it is driven off by vacuum drying at elevated temperature. The resulting resin may be cured with our without the use of pressure using the appropriate cure protocol for DDS. Alternatively, the resin may be used as an application to continuous fibers, such as graphite, to produce a prepreg material for use in composite material fabrication.
6. Application of “Bead-type” POSS Dianiline for the Modification of a Thermosetting Oligomer
According to the molar equivalents and weights of monomers shown in Tables 1 and 2, respectively, 6-FDA monomer was added to an NMP solution of ODA and/or POSS in a dry nitrogen environment. After allowing the reaction to proceed for 60 min, an NMP solution of PEPA was then added to produce a total concentration of 10 wt % solids. The reaction was allowed to stir overnight in a dry nitrogen environment. 15 mL of toluene was added and the reaction was heated to 155° C. using the Dean-Stark methodology to promote imidization. FTIR is used to ensure the achievement of full imidization. A solvent extraction to separate NMP from oligomer was then performed using 15 mL of chloroform and distilled water. Excess chloroform was removed under reduced pressure; the reaction mixture was then added drop-wise to methanol and allowed to stir overnight. The solid product was collected by filtration and washed with methanol. The solid product was dried under vacuum and subsequently characterized by 1 H, 13 C, and 29 Si NMR.
TABLE 1
Equivalents of monomers used to synthesize each of the oligoimides.
Compound
PEPA
6-FDA
ODA
POSS
Mol. Wt.
248.23
444.24
200.24
1335.98
Formula
C 16 H 8 O 3
C 19 H 6 F 6 O 6
C12H12N2O
C 62 H 58 N 2 O 14 Si 10
0 POSS
2
4
5
0
1 POSS
2
4
4
1
2 POSS
2
4
3
2
3 POSS
2
4
2
3
4 POSS
2
4
1
4
5 POSS
2
4
0
5
TABLE 2
Amounts of monomers used in each of the six oligoimides.
Target Oligomer
Molecular
Mmoles
PE
6-FDA
ODA
POSS
Wt. %
(Avg. mol. for.)
Weight
in 7.00 g
(g)
(g)
(g)
(g)
Si 10 O 14
C 168 H 80 F 24 N 10 O 25
3094.45
2.2624
1.1228
4.0194
2.2645
0.000
0.0%
C 218 H 126 F 24 N 10 O 38 Si 10
4230.19
1.6548
0.8218
2.9407
1.3251
2.2106
8.33%
C 268 H 172 F 24 N 10 O 51 Si 20
5365.94
1.3048
0.6475
2.3184
0.784
3.4853
13.16%
C 318 H 218 F 24 N 10 O 64 Si 30
6501.69
1.0766
0.5348
1.9131
0.262
4.3148
16.31%
C 368 H 264 F 24 N 10 O 77 Si 40
7637.44
0.9163
0.4550
2.3289
0.1834
4.8979
18.48%
C 418 H 310 F 24 N 10 O 90 Si 50
8773.18
0.798
0.3962
1.4175
0.000
5.3298
20.16%
7. Application of “Pendant-type” PEPI POSS to the Modification of a Thermosetting Oligomer
To 10 g of a thermosetting oligomer powder comprised of repeat units consisting of the monomers 6-FDA and ODA, end-capped with PEPA, 10 percent by weight, or 1.11 g of “bead-type” PEPI POSS powder is added. The resultant binary powder mixture may be homogenized by (A.) melt blending with conventional polymer blending and compounding equipment between the temperatures of 220° C. and 270° C. for 5 min followed by injection into an appropriately shaped mold and cured under a pressure of 100 psi at 371° C. for 1 hr, or (B.) dissolving the resultant binary powder mixture in a common solvent, such as NMP, at a solute concentration of 10 percent by weight, and precipitated with the use of a common non-solvent, such as methanol. The resultant powder is isolated and dried. The isolated material may be compression molded in purely resin form at 100 psi and cured, in-situ, at 371° C. for 1 hr. Alternatively, the co-solution of the binary mixture may be used as an application to continuous fibers, such as graphite, and the majority of the solvent may be driven off using an oven, to produce a prepreg material for use in composite material fabrication. | Novel POSS mono- and dianiline compounds, their synthesis procedures, and applications in host materials for the purposes of property enhancement are described. This class of POSS compounds features completely aromatic peripheries and partial amine functionality for facile and controlled reactive incorporation into a variety of polymers, and further utility may be derived from reactions of the available amine groups with anhydrides such as phenylethynyl phthalic anhydride (PEPA) to form reactive imide-type oligomers for incorporation into high performance thermosetting polymers. Modification of polymer hosts with the subject nanoparticles can result in a variety of property improvements including mechanical, thermal, tribological, electrical, as well as improved moisture resistance. | 2 |
FIELD OF THE INVENTION
This invention relates to poly(ethylene 2,6-naphthalene dicarboxylate) blends having reduced fluorescence. More specifically, the process involves melt blending poly(ethylene 2,6-naphthalene dicarboxylate) with 0.1 to 5 weight percent of a fluorescence quenching compound selected from a halogen containing aromatic compound, an aromatic ketone or a naphthol compound and thermoforming the blend into an article. The blends are useful for packaging applications where clarity and/or aesthetic appeal are of concern.
BACKGROUND OF THE INVENTION
Poly(ethylene-2,6-naphthalene dicarboxylate), referred to as PEN, is widely used as an extrusion and injection-molding resin because of its good heat resistance, high glass transition temperature, and gas barrier properties. PEN is used in the fabrication of various articles for household or industrial use, including appliance parts, containers, and auto parts. One major drawback of PEN, however, is its inherent bluish fluorescence. Thus, objects prepared with PEN have a hazy and bluish appearance. This phenomenon is especially of concern in the packaging of foods and beverages wherein the food or beverage inside the PEN container appears unnatural.
Fluorescence is a type of luminescence in which an atom or molecule emits radiation in passing from a higher to a lower electronic state. The term is restricted to phenomena in which the time interval between absorption and emission of energy is extremely short (10 -10 to 10 -6 second). Fluorescence in a polymer or small molecule, occurs when a photon is emitted from an excited singlet state. Quenching of fluorescence eliminates or reduces the ability for photon emission by providing an alternative pathway for the excited state energy such as vibronic or heat loss, or intersystem crossing to the excited triplet state.
Methods to quench fluorescence in PEN have been disclosed by Chen Shangxian et al. in an article entitled, "Fluorescence Spectra of Poly(Ethylene-2,6-Naphthalene Dicarboxylate)" which appeared in SCIENTIA SINICA, Vol. XXIV, No. 5, May 1981, and by CAO Ti et al. in an article entitled, "Intermolecular Excimer Interaction In Poly(Polytetramethylene Ether Glycol Aryl Dicarboxylate)" which appeared in ACTA CHIMICA SINICA, Vol. 42, No. 1, 1984. Both of the references disclose the use of o-chlorophenol to quench PEN fluorescence in a chloroform solution. Dissolving the PEN in a chloroform solution to disperse the fluorescence quencher therein, however, is not practical on an industrial scale because only very dilute PEN solutions can be prepared. In addition, the PEN must have a low molecular weight to dissolve in the chloroform solution.
In contrast, the present inventors have unexpectedly determined that melt blending poly(ethylene 2,6-naphthalene dicarboxylate) with 0.1 to 5.0 weight percent of a fluorescence quenching compound selected from a halogen containing aromatic compound, an aromatic ketone and a naphthol compound, provided said fluorescence quenching compound contains an aromatic ring having at least one acyl group, halogen atom or hydroxyl group directly attached to the aromatic ring, significantly reduces the fluorescence of the polyester without deleteriously effecting the physical properties of the polyester.
SUMMARY OF THE INVENTION
Accordingly, it is one object of the present invention to provide PEN blends with reduced fluorescence.
Accordingly, it is another object of the invention to provide PEN blends which have reduced fluorescence and are useful in applications where good heat resistance, high glass transition temperature and gas barrier properties are required.
These and other objects are accomplished herein by a process for preparing a poly(ethylene 2,6-naphthalene dicarboxylate) blend which exhibits reduced fluorescence comprising:
(I) melt blending
(A) 95.0 to 99.9 weight percent of a polyester which comprises
(1) a dicarboxylic acid component comprising repeat units from at least 85 mole percent of a dicarboxylic acid selected from the group consisting of naphthalene-2,6-dicarboxylic acid, and naphthalene-2,6--dicarboxylate ester;
(2) a diol component comprising repeat units from at least 85 mole percent ethylene glycol, based on 100 mole percent dicarboxylic acid and 100 mole percent diol; and
(B) 0.1 to 5.0 weight percent of a fluorescence quenching compound selected from the group consisting of a halogen containing aromatic compound, an aromatic ketone and a naphthol compound, provided said fluorescence quenching compound contains an aromatic ring having at least one acyl group, halogen atom or hydroxyl group directly attached to the aromatic ring, wherein the combined weights of (A) and (B) total 100 percent; and
(II) forming the blend into an article.
DESCRIPTION OF THE INVENTION
The polyester of the present invention is poly(ethylene 2,6-naphthalene dicarboxylate). The poly(ethylene 2,6-naphthalene dicarboxylate) contains repeat units from a dicarboxylic acid and a diol. The dicarboxylic acid, component (1), consists of at least 85 mole percent naphthalene-2,6-dicarboxylic acid or naphthalene-2,6--dicarboxylate ester. The diol, component (2), consists of at least 85 mole percent ethylene glycol, based on 100 mole percent dicarboxylic acid and 100 mole percent diol. Preferably, the polyester contains repeat units from at least 90 mole percent naphthalene-2,6-dicarboxylic acid or naphthalene-2,6-dicarboxylate ester, and at least 90 mole percent ethylene glycol. More preferably, the polyester contains at least 95 mole percent naphthalene-2,6--dicarboxylic acid or naphthalene-2,6--dicarboxylate ester, and at least 95 mole percent ethylene glycol.
The dicarboxylic acid component of the polyester may optionally be modified with up to 15 mole percent of one or more different dicarboxylic acids other than naphthalene-2,6-dicarboxylic acid or naphthalene-2,6-dicarboxylate ester. Such additional dicarboxylic acids include aromatic dicarboxylic acids preferably having 8 to 14 carbon atoms, aliphatic dicarboxylic acids preferably having 4 to 12 carbon atoms, or cycloaliphatic dicarboxylic acids preferably having 8 to 12 carbon atoms. Examples of dicarboxylic acids to be included with naphthalene-2,6-dicarboxylic acid or naphthalene-2,6-dicarboxylate ester are: terephthalic acid, phthalic acid, isophthalic acid, cyclohexanediacetic acid, diphenyl-4,4'-dicarboxylic acid, succinic acid, glutaric acid, adipic acid, fumaric acid, azelaic acid, sebacic acid, 2,7-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, resorcinoldiacetic acid, diglycolic acid, 4,4'-oxybis(benzoic) acid, biphenyldicarboxylic acid, 1,12-dodecanedicarboxylic acid, 4,4'-sulfonyldibenzoic acid, 4,4'-methylenedibenzoic acid, trans-4,4'-stilbenedicarboxylic acid, and the like. It should be understood that use of the corresponding acid anhydrides, esters, and acid chlorides of these acids is included in the term "dicarboxylic acid". The polyester may be prepared from one or more of the above dicarboxylic acids or esters.
In addition, the polyester may optionally be modified with up to 15 mole percent, of one or more different diols other than ethylene glycol. Such additional diols include cycloaliphatic diols preferably having 6 to 20 carbon atoms or aliphatic diols preferably having 3 to 20 carbon atoms. Examples of such diols to be included with ethylene glycol are: diethylene glycol, triethylene glycol, 1,4-cyclohexanedimethanol, propane-1,3-diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, 2,2-dimethyl-1,3-propanediol, 1,10-decanediol, 2,2,4,4-tetramethyl-1,3--cyclobutanediol, 3-methylpentanediol-(2,4), 2-methylpentanediol-(1,4), 2,2,4-trimethylpentane-diol-(1,3), 2-ethylhexanediol-(1,3), 2,2-diethylpropane-diol-(1,3), hexanediol-(1,3), 1,4-di-(hydroxyethoxy)-benzene, 2,2-bis-(4-hydroxycyclohexyl)-propane, 2,4-dihydroxy-1,1,3,3-tetramethyl-cyclobutane, 2,2-bis-(3-hydroxyethoxyphenyl)-propane, and 2,2-bis-(4-hydroxypropoxyphenyl)-propane. The polyester may be prepared from one or more of the above diols.
The polyester may also contain small amounts of trifunctional or tetrafunctional comonomers such as trimellitic anhydride, trimethylolpropane, pyromellitic dianhydride, pentaerythritol, and other polyester forming polyacids or diols generally known in the art.
The poly(ethylene-2,6-naphthalene dicarboxylate) is prepared by conventional polycondensation procedures well-known in the art which generally include a combination of melt phase and solid state polymerization. Melt phase describes the molten state of PEN during the initial polymerization process. The initial polymerization process includes direct condensation of the naphthalene-2,6-dicarboxylic acid with the diol(s) or by ester interchange using naphthalene-2,6-dicarboxylic ester. For example, dimethyl-2,6-naphthalenedicarboxylate is ester interchanged with the diol(s) at elevated temperatures in the presence of a catalyst. The melt phase is concluded by extruding the PEN polymer into strands and pelletizing. The PEN polymer may optionally be solid state polymerized. Solid state polymerization involves heating the PEN pellets to a temperature in excess of 200° C., but well below the crystalline melt point, either in the presence of an inert gas stream or in a vacuum to remove a diol. Several hours are generally required in the solid state polymerization unit to build the molecular weight to the target level.
Typical polyesterification catalysts which may be used include titanium alkoxides, dibutyl tin dilaurate, combinations of zinc, manganese, or magnesium acetates or benzoates with antimony oxide or antimony triacetate.
The poly(ethylene-2,6-naphthalene dicarboxylate) polymers of the present invention have a melting point (Tm) of about 263°C. ±10° C. and a glass transition temperature (Tg) of about 125°C. ±5C. The inherent viscosity of the polyester should be 0.3 to 1.5 dL/g. However, inherent viscosities of from 0.5 to 0.9 are preferred, as measured at 25° C. using 0.50 grams of polymer per 100 ml of a solvent consisting of 60% by weight phenol and 40% by weight tetrachloroethane.
Component (B) of the present invention is 0.1 to 5 weight percent of a fluorescence quenching compound. Preferably, the range of the fluorescence quenching compound is 0.3 to 2.5 weight percent of the blend. Using more than 5 weight percent of the fluorescence quenching compound deleteriously effects the physical properties such as tensile strength, flexural modulus, elongation percent, weather resistance and heat deflection of the PEN.
The fluorescence quenching compounds useful in the present invention are halogen containing aromatic compounds, aromatic ketones and naphthol compounds. Preferably, the fluorescence quenching compounds do not impart color to the PEN when blended. The fluorescence quenching compounds contain an aromatic ring selected from benzene, naphthalene, biphenyl and anthracene. The aromatic ring of the fluorescence quenching compound contains at least one acyl group, halogen atom, and/or hydroxyl group directly attached to the aromatic ring. The acyl group has the structure ##STR1## wherein R 4 is selected from unsubstituted and substituted C 1 -C 10 alkyl, unsubstituted and substituted phenyl, and unsubstituted and substituted naphthyl groups. C 1 -C 10 unsubstituted and substituted alkyl groups represented by R 4 include straight or branched chain fully saturated hydrocarbon radicals and these substituted with one or more of the following: C 5 -C 7 cycloalkyl, and C 5 -C 7 cycloalkyl substituted with one or two of C 1 -C 6 alkyl, C 1 -C 6 alkoxy or halogen. The substituted phenyl groups mentioned above, unless otherwise specified, represent such phenyl groups substituted by one or two of C 1 -C 6 alkyl. The alkyl, phenyl and naphthyl groups of R 4 may contain any substituent thereon as long as such substituents do not deleteriously effect the fluorescence quenching of the copolymerized aromatic ketone. Examples of acyl groups include acetyl, benzoyl, 1- or 2-naphthoyl, and propionyl. Preferred acyl groups are benzoyl and 1- or 2-naphthoyl. The most preferred acyl group is the benzoyl group (C 6 H 5 CO--).
In addition to the acyl group or in replace of the acyl group, the aromatic ring contains at least one halogen atom or hydroxyl group. The halogen atom is selected from bromine, chlorine, or iodine, provided that chlorine is not used alone unless an acyl group, as discussed above, is present. While not wishing to be bound by any particular mechanism or theory, the present inventors believe that the large atomic weights of bromine and iodine enhance intersystem crossing while the atomic weight of chlorine is too low to effectively function by this quenching mechanism. The halogen atoms can be attached to any of the unsubstituted positions on the aromatic rings. Preferred halogen atoms are iodine and bromine.
Optionally, polymerizable groups such as carboxylic esters and/or aliphatic hydroxyl groups may be attached to the aromatic ring. The carboxylic ester has the formula: ##STR2## wherein R 3 is selected from a substituted and unsubstituted C 1 -C 6 alkyl group and a substituted and unsubstituted phenyl group. C 1 -C 6 unsubstituted and substituted alkyl groups represented by R 3 include straight or branched chain fully saturated hydrocarbon radicals and these substituted with one or more of the following: C 5 -C 7 cycloalkyl, and C 5 -C 7 cycloalkyl substituted with one or two of C 1 -C 6 alkyl, C 1 -C 6 alkoxy or halogen. The substituted phenyl groups represent such phenyl groups substituted by one or two of C 1 -C 6 alkyl. Preferably R 3 is methyl.
The aliphatic hydroxyl group has the formula:
(CH.sub.2).sub.n OH
wherein n is an integer from 1 to 6, preferably n is 2k. Examples of aromatic ring compounds containing carboxylic esters and/or aliphatic hydroxyl groups are terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid. The fluorescence quenching compounds containing carboxylic esters and/or aliphatic hydroxyl groups can potentially react with the PEN polymer chain in the melt at high temperatures but chemical reaction is not essential for the purpose of this invention and a mere physical blend produces the desired result. However, fluorescence quenching compounds with high boiling points are desirable in order to minimize losses of the active compounds during processing or molding of the PEN polymer.
Examples of fluorescence quenching compounds to be melt blended with PEN include:
Dimethyl 1-benzoyl 2,6-naphthalenedicarboxylate
Dimethyl 3-benzoyl 2,6-naphthalenedicarboxylate
Dimethyl 4-benzoyl 2,6-naphthalenedicarboxylate
Dimethyl 1-bromo 2,6-naphthalenedicarboxylate
Dimethyl 3-bromo 2,6-naphthalenedicarboxylate
Dimethyl 4-bromo 2,6-naphthalenedicarboxylate
Dimethyl 1-(2-naphthoyl) 2,6-naphthalenedicarboxylate
Dimethyl 1-(1-naphthoyl) 2,6-naphthalenedicarboxylate
Dimethyl 1-iodo 2,6-naphthalenedicarboxylate
Dimethyl 3-iodo 2,6-naphthalenedicarboxylate
Dimethyl 4-iodo 2,6-naphthalenedicarboxylate
Dimethyl benzoylterephthalate
Dimethyl benzoylisophthalate
Dimethyl iodoterephthalate
Dimethyl 2,3-dibromoterephthalate
Dimethyl 2,5-dibromoterephthalate
Dimethyl tribromoterephthalate
Dimethyl tetrabromoterephthalate
Dimethyl 2-bromo-5-chloroterephthalate
Dimethyl 2-bromo-6-chloroterephthalate
Dimethyl 2-bromo-5-iodoterephthalate
Dimethyl 2-bromo-6-iodoterephthalate
Dimethyl 2-benzoyl-5-bromoterephthalate
Dimethyl 2-benzoyl-6-bromoterephthalate
Dimethyl 2-benzoyl-5-iodoterephthalate
Dimethyl 2-benzoyl-6-iodoterephthalate
4-Chloro-l-naphthol
9,10-Dibromoanthracene
2,6-Diiodonaphthalene
1-Naphthol
1,2-Dibenzoylbenzene
2-Benzoylnaphthalene
1-Benzoylnaphthalene
polyhalogenated 2,6- or 2,7-naphthalenedicarboxylic acids or their diesters, and the like compounds.
The fluorescence quenching compound, component (B), can be added with stirring while the molten PEN polymer is protected by an inert atmosphere such as dry nitrogen. Although PEN is not very soluble in most common organic solvents, solution blends can be made in certain solvents such as in phenol/tetrachloroethane blends. A preferred method of making the blends involves the melt extrusion of the PEN and the additives in extrusion equipment such as that available from Brabender and Werner-Pfleiderer.
Many other ingredients can be added to the blends of the present invention to enhance the performance properties of the blends. For example, surface lubricants, denesting agents, stabilizers, antioxidants, ultraviolet light absorbing agents, mold release agents, metal deactivators, colorants such as black iron oxide and carbon black, nucleating agents, phosphate stabilizers, zeolites, fillers, and the like, can be included herein. All of these additives and the use thereof are well known in the art. Any of these compounds can be used so long as they do not hinder the present invention from accomplishing its objects.
The poly(ethylene-2,6-naphthalene dicarboxylate) blends serve as excellent starting materials for the production of moldings of all types. Specific applications include food packaging such as bottles, trays, lids and films, medical parts, appliance parts, automotive parts, tool housings, recreational and utility parts. The blends of the present invention are especially useful in applications that require transparent molded parts. Additionally, the blends can be used to prepare extruded sheets for thermoforming applications. The blends are readily extruded into films or processed into monolayer or multilayer food and beverage containers. Potential methods for producing containers include: (1) injection stretch blow molding using either one or two stage technology, (2) injection blow molding, (3) extrusion blow molding, (4) pipe extrusion, and (5) co-injection or coextrusion where the blends can serve as either the structural layer or barrier layer depending upon end use requirements. Fibers, melt-blown webs, extruded sheets, vacuum-drawn trays/parts, Injection molded parts, and extrusion coated wires may also be made from these blends.
The materials and testing procedures used for the results shown herein are as follows:
Fluorescence Intensity was determined using a Perkin-Elmer LS5B Luminescence Spectrometer which measured relative fluorescence intensity at peak maxima.
Inherent viscosity (I.V.) was measured at 25° C. using 0.50 grams of polymer per 100 ml of a solvent consisting of 60% by weight phenol and 40% by weight tetrachloroethane.
Sample preparation for determining fluorescence intensity involved grinding the polyester blend samples to 3-4 mm. The samples were micropulverized in an analytical grinding mill and passed through a 120 mesh screen. The powders were dried for 24 hours at 140° C. Approximately 0.5 grams of the powder was packed into a sample holder and measurements were taken by reflectance. The excitation wavelength was 350 nm and the emission maxima was 428-432 nm for all of the samples. The values are reported as normalized to PEN (fluorescence intensity 100). The fluorescence intensity of the blends was repeated 10 times with a standard deviation of 5.0. Two measurements were taken of all other samples and the averages are reported in Table I.
The blends of the present invention will be further illustrated by a consideration of the following examples, which are intended to be exemplary of the invention. All parts and percentages in the examples are on a weight basis unless otherwise stated.
EXAMPLE 1
Poly(ethylene 2,6-naphthalene dicarboxylate) was prepared by the following procedure.
Dimethyl 2,6-naphthalene dicarboxylate (0.5 moles, 122 grams), ethylene glycol (1.0 moles, 62 grams), and catalyst metals were placed in a 500 mL polymerization reactor under a nitrogen atmosphere. The mixture was heated with stirring at 200° C. for 2 hours. The temperature was increased to 220° C. and maintained for 1 hour. The temperature was increased to 290° C. which took approximately 20 minutes. When the temperature reached 290° C., the nitrogen flow was stopped and vacuum was applied. The polymer was stirred under vacuum (0.1-0.3 mm Hg) for 50 minutes. The polymer was cooled and ground. The PEN had an I.V. of 0.55 dL/g. The fluorescence intensity of the polymer is listed in Table I.
EXAMPLE 2
Melt blending of dimethyl benzoylterephthalate with PEN.
PEN polymer pellets, 500 grams, prepared in Example 1 were dried for 12 hours at 160° C. in desiccant air with a dew point ≦-29° C. and placed in a plastic bag. Dimethyl benzoylterephthalate powder, 5 grams, (1 wt %) was added to the plastic bag. The dimethyl benzoylterephthalate and PEN were dry blended by shaking the plastic bag.
Dry PEN polymer was flushed through a Brabender single screw extruder to purge the extruder. The dry blend PEN/dimethyl benzoylterephthalate was passed through the extruder with the three heated zones maintained at 270° C., 290° C., and 290° C. The melt blended sample was extruded into a rod, cooled in water, and chopped into 1/8 inch pellets. The pellets were crystallized in an air oven at 225° C. for 45 minutes and then ground into powder in order to determine the fluorescence intensity. The fluorescence intensity of the blend is listed in Table I.
EXAMPLE 3
Melt blending of dimethyl iodoterephthalate with PEN.
Dimethyl iodoterephthalate, 5.0 grams, (1 wt %) was melt blended with the PEN prepared in Example 1 by the procedure set forth in Example 2. The fluorescence intensity of the blend is listed in Table I.
EXAMPLE 4
Melt blending of 4-chloro-1-naphthol with PEN.
4-chloro-1-naphthol, 5.0 grams, (1 wt %) was melt blended with the PEN prepared in Example 1 by the procedure set forth in Example 2. The fluorescence intensity of the blend is listed in Table I.
EXAMPLE 5
Melt blending of 9,10-dibromoanthracene with PEN.
9,10-Dibromoanthracene, 5.0 grams, (1 wt %) was melt blended with the PEN prepared in Example 1 by the procedure set forth in Example 2. The fluorescence intensity of the blend is listed in Table I.
EXAMPLE 6
Melt blending of 2,6-diiodonaphthalene with PEN.
2,6-Diiodonaphthalene, 5.0 grams, (1 wt %) was melt blended with the PEN prepared in Example 1 by the procedure set forth in Example 2. The fluorescence intensity of the blend is listed in Table I.
EXAMPLE 7
Melt blending of dimethyl iodoterephthalate with PEN.
Dimethyl iodoterephthalate, 10 grams, (2 wt %) was melt blended with the PEN prepared in Example 1 by the procedure set forth in Example 2. The fluorescence intensity of the blend is listed in Table I.
EXAMPLE 8
Melt blending of 1-naphthol with PEN.
1-Naphthol, 3.0 grams, (0.6 wt %) was melt blended with the PEN prepared in Example 1 by the procedure set forth in Example 2. The fluorescence intensity of the blend is listed in Table I.
EXAMPLE 9
Melt blending of 1,2-dibenzoylbenzene with PEN.
1,2-Dibenzoylbenzene, 2.9 grams, (0.6 wt %) was melt blended with the PEN prepared in Example 1 by the procedure set forth in Example 2. The fluorescence intensity of the blend is listed in Table I.
EXAMPLE 10
Melt blending of 2-benzoylnaphthalene with PEN.
2-Benzoylnaphthalene, 2.4 grams, (0.5 wt %) was melt blended with the PEN prepared in Example 1 by the procedure set forth in Example 2. The fluorescence intensity of the blend is listed in Table I.
EXAMPLE 11
Melt blending of dimethyl 1-benzoyl-2,6-naphthalene dicarboxylate with PEN.
Dimethyl 1-benzoyl-2,6-naphthalene dicarboxylate, 5.0 grams, (1 wt %) is melt blended with the PEN prepared in Example 1 by the procedure set forth in Example 2. The fluorescence intensity of the blend is listed in Table I.
EXAMPLE 12
Melt blending of dimethyl 1-benzoyl-2,6-naphthalene dicarboxylate with PEN.
Dimethyl 1-benzoyl-2,6-naphthalene dicarboxylate, 10 grams, (2 wt %) is melt blended with the PEN prepared in Example 1 by the procedure set forth in Example 2. The fluorescence intensity of the blend is listed in Table I.
EXAMPLE 13
Melt blending of dimethyl 1-benzoyl-2,6-naphthalene dicarboxylate with PEN.
Dimethyl 1-benzoyl-2,6-naphthalene dicarboxylate, 25 grams, (5 wt %) is melt blended with the PEN prepared in Example 1 by the procedure set forth in Example 2. The fluorescence intensity of the blend is listed in Table I.
EXAMPLE 14
Melt blending of dimethyl 1-(2-naphthoyl)-2,6- naphthalene dicarboxylate with PEN.
Dimethyl 1-(2-naphthoyl)-2,6--naphthalene dicarboxylate, 5.0 grams, (1 wt %) is melt blended with the PEN prepared in Example 1 by the procedure set forth in Example 2. The fluorescence intensity of the blend is listed in Table I.
TABLE I______________________________________FLUORESCENCE FLUORESCENCEQUENCHER INTENSITYEX. (type) (wt %) (at 430 nm)______________________________________1 PEN control -- 1002 dimethyl benzoyl- 1.0 71terephthalate3 dimethyl iodoterephthalate 1.0 834 4-chloro-1-naphthol 1.0 335 9,10-dibromoanthracene 1.0 206 2,6-diiodonaphthalene 1.0 777 dimethyl iodoterephthalate 2.0 788 1-naphthol 0.6 579 1,2-dibenzoylbenzene 0.6 6810 2-benzoylnaphthalene 0.5 5711 dimethyl 1-benzoyl-2,6- 1.0 45-55naphthalene dicarboxylate12 dimethyl 1-benzoyl-2,6- 2.0 30-40naphthalene dicarboxylate13 dimethyl 1-benzoyl-2,6- 5.0 20-30naphthalene dicarboxylate14 dimethyl 1-(2-naphthoyl)-2,6- 1.0 40-50naphthalene dicarboxylate______________________________________
The results in Table I clearly indicate that the poly(ethylene-2,6-naphthalene dicarboxylate) blends containing a critical range of a fluorescence quenching compound selected from a halogen containing aromatic compound, an aromatic ketone or a naphthol compound, which is melt blended with the PEN, exhibit significantly less fluorescence than PEN compositions without the fluorescence quencher. The use of the fluorescence quencher in a critical amount does not deleteriously effect the physical properties of the blends.
Many variations will suggest themselves to those skilled in this art in light of the above detailed description. All such obvious modifications are within the full intended scope of the appended claims. | This invention relates to poly(ethylene 2,6-naphthalene dicarboxylate) blends having reduced fluorescence. More specifically, the process involves melt blending poly(ethylene 2,6-naphthalene dicarboxylate) with 0.1 to 5 weight percent of a fluorescence quenching compound selected from a halogen containing aromatic compound, an aromatic ketone or a naphthol compound and thermoforming the blend into an article. The blends are useful for packaging applications where clarity and/or aesthetic appeal are of concern. | 2 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to the field of structure-borne noise reduction, and more particularly to apparatus for countering vibrations of elements coupled to the structure.
2. Description of the Prior Art
Ring laser gyroscopes (RLG) utilize two monochromatic laser beams propagating in opposite directions about a closed loop. Rotation of the apparatus about the loop axis effectively increases the beam path length in one direction and decreases the beam path in the opposite direction. Since the laser frequencies of the two counter-rotating beams are functions of the lasing path length, the differential path length established by the rotation of the RLG causes a frequency difference between the two beams. The magnitude and sign of this frequency difference are representative of the RLG's rate and direction of rotation and may be monitored for these purposes in manners well known in the art. At low rotation rates, the frequency difference between the counter-rotating beams is small and the beams tend to resonate at the same frequency, i.e. lock-in, and the RLG appears to be stationary. This lock-in prevents the RLG from sensing rotation rates that are at or below the lock-in rate. To reduce the lock-in rate, the RLG is mechanically oscillated, dithered, about its axis to establish rotation in one direction and then the other. Such dithering provides a signal at the output terminals that is substantially independent of the mechanical oscillation while maintaining an apparent rotation in each direction, thus reducing the lock-in rotation rate.
The dithering causes the structure on which the RLG is mounted to vibrate, thereby generating structure-borne noise which adversely effects equipment mechanically coupled to the mounting structure. One method of the prior art for reducing structure-borne noise is disclosed in U.S. Pat. No. 5,012,174 issued to Charles M. Adkins, et al and assigned to the assignee of the present invention. Adkins, et al teach a device which is attached directly to the RLG platform and electronically establishes counter vibrations of the platform to cancel vibrations induced by the dithering RLG. The apparatus taught by Adkins, et al, however, is complex mechanically and electrically and is too expensive for use with the relatively inexpensive RLG.
Another method of the prior art for reducing structure-borne noise is disclosed in U.S. Pat. No. 5,267,720 issued to James R. Brazell, et al and assigned to the assignee of the present invention. Brazell, et al teach the use of a pair of noise attenuator assemblies positioned along mutually perpendicular rotational axes. Each noise attenuator includes a precision ground valve spring captivated in a highly damped elastomeric material molded to a machined housing. Matching of the noise attenuators and alignment of the rotational axes must be performed to close tolerances to achieve the required platform stabilization. Suppression of mechanical resonances of the sensor supporting structure is achieved by applying a viscoelastic constrained layer to 90 percent of the external surfaces. To meet shock, vibration, and structure-borne noise isolation, high precision machining, tight tolerances on molded elastomers, matched preloaded noise attenuators, and extensive inspection are required. Thus, the device is difficult to manufacture and assemble and therefore, costly.
The above limitations were overcome by the invention disclosed in U.S. Pat. No. 6,056,259 issued to Jamil I. Lahham and assigned to the assignee of the present invention. This patent teaches the utilization of a tunable auxiliary mass coupled to an element vibrating at forced vibration frequencies. The auxiliary mass is tuned to vibrate at the forced vibration frequencies out of phase with the element vibrations, thus reducing the structure-borne noise.
Included in the auxiliary mass is a four cavity chamber, each having a flat base and a flat top. These cavities are filled to capacity with steel shots to provide the mass and stiffness required to achieve the desired tuned vibration frequency. Chamber and steel shot tolerances, however, establish a random steel shot arrangement geometry. This randomness, however slight, may, for some assemblies, provide an auxiliary mass that may not be appropriately tuned, thereby requiring iterations of re-assemblies and concomitant structure-borne noise measurements to achieve the desired auxiliary mass vibration frequency.
SUMMARY OF THE INVENTION
In accordance with the present invention the randomness of the steel shot arrangement is substantially eliminated by constructing the four cavity chamber with the base of each cavity containing a multiplicity of grooves which contain and guide spherical elements, such as steel ball bearings. The grooves are positioned and dimensioned so that the spherical elements fill each cavity in a touch relationship with adjacent spherical elements and cavity walls. Arranging the spherical elements and grooves in this manner maintains the spherical elements motionless in each cavity.
These and other aspects of the invention will be more fully understood by referring to following detailed description and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded view of an assembly of a vibration forcing unit, its housing, and a preferred embodiment of the invention.
FIGS. 2A, 2 B, and 2 C provide details of the four cavity auxiliary mass shown in FIG. 1
FIG. 3A illustrates the pyramidal configuration for the nesting pattern of the spherical elements within a cavity.
FIG. 3B shows the relationship of a top spherical element of FIG. 3A to two of the lower spherical elements.
FIGS. 4A and 4B are top and side views, respectively, of the nesting pattern.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Refer now to FIG. 1. A vibrating device 11 , such as a dithered RLG, may be positioned in a housing 13 , which may be closed by a cover 15 containing the electronics required for an RLG operation. External forces acting on a body cause the body to vibrate at the forcing frequencies generated by the external forces. Vibrations of the device 11 , such as the dithering of an RLG, cause forced vibrations of the housing-cover assembly 13 , 15 , which act as a unit body. The forced vibrations are at the forcing frequencies generated by the vibrating device 11 . As explained in U.S. Pat. No. 6,056,259, which is incorporated herein by reference, to reduce the vibration amplitudes of the housing-cover assembly 13 , 15 response to the forcing frequencies, the housing-cover assembly 13 , 15 is designed to have a natural frequency ω 0 that is lower than the lowest forcing frequency. It is well known that the natural frequency of a body is determined from ω 0 2 =k/m, where k is the stiffness of the body and m its mass. Therefore, a natural frequency ω 0 may be positioned below the lowest forcing frequency with the selection of construction material, wall thickness, and points of constraints about the housing to establish the proper ratio of k/m. For a resonant frequency above the fundamental mode, an auxiliary mass 17 is attached to the housing cover assembly 13 , 15 so that the combined system resonance is minimized in the forcing frequency range. To accomplish this, the amplitude x 0 of the forced vibration of a single degree of freedom system should be minimized. For an undamped system x 0 is known to be in the order of x 0 = P 0 k 0 [ 1 - ( ω ω 0 ) 2 ]
where:
P 0 is the amplitude of the exciting force
k 0 =m 0 ω 0 2
m 0 is the mass of the housing-cover assembly 13 , 15
ω is the forcing frequency
ω 0 is the natural frequency of the housing-cover assembly
P 0 /k 0 is the static deflection of a theoretical spring.
It is evident from the above equation that the deflection amplitude is decreased by increasing the value of k 0 . This may be accomplished by increasing the mass mo with the concomitant increase in the value of k 0 . Coupling an auxiliary mass 17 to the housing-cover assembly 13 , 15 adds a mass m eq to the overall system that is given by: m eq = m am 1 - ( ω ω am ) 2
where,
m eq is the equivalent mass added by the auxiliary mass system
m am is the actual mass of the auxiliary mass assembly 17
ω am is the natural frequency of the auxiliary mass
Addition of the equivalent mass establishes a vibration amplitude for the combined system that is a function of a forced frequency ratio β am =ω/ω am , the mass ratio μ=m am /m, and the static deflection of the housing-cover assembly 13 , 15 , which may be determined from x 0 = P 0 k ( 1 - β am 2 ) ( 1 - β am 2 ) ( 1 - β 2 ) - β 2 μ
where
β=ω/ω 0
From the above it is evident that the vibration amplitude x 0 at a forcing frequency ω is substantially zero when the auxiliary mass resonance frequency is tuned to the forcing frequency, i.e. ω am =ω or equivalently β am =1.
As previously stated, to minimize vibrations, the housing-cover assembly 13 , 15 is constructed such that its first fundamental frequency is out of the forcing frequency band of the vibrating device 11 . It is preferable that this natural frequency be chosen below the forcing frequency band.
To reduce the vibration amplitudes within the forcing frequency band an auxiliary mass 17 , having one natural frequency above the forcing frequency band, is added to the housing-cover assembly 13 , 15 . The auxiliary mass 17 comprises a sectionalized base plate 19 , which may have four cavities, each cavity having a multiplicity of grooves 20 in the base plate 19 , as shown in FIG. 2A, A normal view of the base 19 with the grooves 20 is shown in FIG. 2 C. Spherical elements, such as stainless steel ball bearings 21 , are positioned in the grooves between the base plate 19 and a cover 23 to fill each section. The cover 23 has raised sections 23 a, as shown in FIG. 2B, which form the top walls of the cavities. The ball bearings are sized to be restrained by the cover 23 , grooves 20 in the base plate 19 and notches 20 a in the side walls of the base plate 19 to maintain a predictable arrangement in the cavities and to insure motionless contact with adjacent ball bearings, the base plate, the cover, and the side walls. For clarity, only a limited number of ball bearings are shown in the figures. Precision machining of grooves in the base plate 19 and notches 20 a in the side walls to fit the curvature of the ball bearings provide a compact nesting pattern in the cavities for the stainless steel ball bearings.
This geometry allows the ball bearings 21 , to fit in a stable nesting pattern of a basic three cornered pyramid configuration 30 as shown in FIG. 3A, thus assuring that the ball bearings remain in a contacting relationship with all adjacent ball bearings and walls and eliminating a random geometry for the positioning of the ball bearings. The combination of stainless steel ball bearings positioned in precision machined grooves in the base plate, cover, and notches in the side walls insures a predictable assembly of the auxiliary mass.
The relationship of the top ball bearing 34 to two of the lower ball bearings is shown in FIG. 3 B. In this figure it should be recognized that the spacing 31 of the centers 32 a and 32 b of the two lower ball bearings 33 a and 33 b is 2 r, where r is the radius of each ball bearing. When the upper ball bearing 34 is positioned in the pyramid 30 its center 35 is in a plane that is offset from the plane of the centers 32 a and 32 b of the lower ball bearings 33 a, 33 b by a distance 36 that is equal to 0.577 r, while the slant distances 39 to the projection point of the upper ball center to the plane is 1.155 r. The slant distances 37 between the lower ball bearing centers and the upper ball bearing center is 1.732 r.
Top and side views of nested ball bearing sections are shown in FIGS. 4A and 4B. It is evident that the separation 41 between centers of adjacent ball bearings at the same nesting level in any row is 2 r. In the nesting arrangement adjacent rows at the same nesting level are offset. This offset causes a ball bearing of one row to be positioned in the crevice between two contacting ball bearings of the adjacent row. Consequently, the center spacings 43 between ball bearings in adjacent rows are less than the center spacings between adjacent ball bearings in the same row. As a result of this crevice positioning the center spacings 37 , shown in FIG. 3B, between ball bearings in adjacent rows are 1.732 r. Further, in the nesting arrangement a ball bearing in the upper layer is positioned in the crevice formed by three adjacent ball bearings in the lower layer, as shown in FIG. 3 A. This causes the separation 45 between ball bearing centers in adjacent layers to be even less than the separation between centers in the same layer. As a consequence of the positioning of ball bearings in the upper layer in the crevices between three ball bearings of the lower layer the ball bearing center separations 45 between layers are 1.632 r, resulting in an overall height 47 for a two layer nesting arrangement of 3.632 r.
Refer again to FIG. 1 . Screws 25 a, 25 b, and 25 c, which extend through pass-through holes 24 a, 24 b, and 24 c in the cover 23 and pass-through holes 22 a, 22 b, and 22 c in the base plate 19 to threaded holes below spacers 27 a, 27 b, and 27 c, couple the auxiliary mass 17 to the housing assembly 13 , 15 . A predetermined uniform air-gap between the housing 13 and the auxiliary mass 17 is achieved with the utilization of the spacers above 27 a, 27 b, and 27 c and by seating the auxiliary mass 17 on a casted boss 29 on the housing 13 .
The stainless steel ball bearings utilized to fill the cavities provides the desired combination of mass and rigidity for the auxiliary mass. The total mass of the auxiliary mass is computed to achieve the desired tuning frequency and to place the combined system resonances outside the forcing frequency band. A characteristic equation for the combined housing-cover 13 , 15 and auxiliary mass 17 may be provided by setting the denominator of the preceding equation to zero, as shown.
(1−β am 2 ) (1−β 2 )−β 2 μ=0
Setting ω n =ω and rewriting this equation as a function of ω n ,ω 0 , ω am and μ establishes the following equation
(ω n 2 −ω am 2 )(ω n 2 −ω o 2 )−ω n 2 ω am 2 μ=0
which is the characteristic equation of the combined system from which the combined system resonance frequency ω n is computed as ω n 2 = ω am 2 ( 1 + μ ) - ω 0 2 2 ± [ ω am 2 ( 1 + μ ) - ω 0 2 2 ] 2 + ω am 2 ω 0 2 μ
This equation determines the squares of the combined system resonant frequencies ω n1 and ω n2 for a selected mass ratio μ=m am /m. Computations for various mass ratios permits the selection of a resonant frequencies that are outside the forcing frequency band.
For example, consider a forcing frequency band between 450 Hz and 650 Hz,housing-cover assembly 13 , 15 with a weight of 20 lbs and having a natural frequency of 534 Hz and selected mass ratios of 0.1, 0.2, and 0.25. For this situation the combined system resonances can be selected for the undesired resonance of 534 Hz.
For μ m =0.1:
ω n1 =1.18ω am =630.1 Hz
ω n2 =0.88ω am =469.9 Hz
Since both ω n1 and ω n2 are within the forcing frequency band, this mass ratio is not adequate.
For μ=0.2:
ω n1 =1.25ω am =667.5 Hz
ω n2 0.80ω am =427.2 Hz
These frequencies, though outside the forcing frequency band, too close to the band edges, especially at the upper end.
For μ=0.25:
ω n1 =1.13ω am =694.2 Hz
ω n2 =0.78ω am =416.5 Hz
This mass ratio is adequate to place the resonant frequency of combined system, housing-cover and auxiliary mass 13 , 15 and 17 , comfortably outside the forcing frequency band. Thus the mass ratio 0.25 eliminates the resonance of the housing-cover assembly 13 , 15 .
A higher mass ratio widens the dead frequency band for the combined system at the expense of increasing the overall weight of the unit and the stiffness of the auxiliary mass to maintain the same ω am . This is not attractive. Thus the total weight of the auxiliary mass, m am , is 5 lbs (0.25×20 lbs) . Further, weight is equal to mass times the acceleration of gravity (w=mg; g=386 in/sec 2 ). Thus, the total mass of the auxiliary mass 17 is m am =0.01295 lbs·sec 2 /in. Since the rigidity of the auxiliary mass may be determined from k am =ω am 2 m am , the rigidity k am of the auxiliary mass 17 may be (534×2π) 2 ×0.01295=145785 lbs/in, which is its total spring stiffness.
The construction of the auxiliary mass 17 and the screws 25 a, 25 b, and 25 c establish a tuning mass-spring system which may be fine tuned by adjusting the torque on the screws to counteract forced vibrations of the housing-cover assembly 13 , 15 . Attachment points 27 a, 27 b, and 27 c on the housing 13 for accepting the coupling screws 25 a, 25 b, and 25 c, respectively, are selected to maximize the housing-cover 13 , 15 motion suppression and to enhance the stability of the auxiliary mass 17 during externally induced sinusoidal and random environmental vibration at the resonance frequency of the combined structure. The reactive force performance of the auxiliary mass 17 is significantly increased by triangularly positioning coupling points 27 a, 27 b and 27 c as shown in FIG. 1 . Positioning the coupling points in this manner enforces nodes at locations 27 a and 27 c for the forced vibration frequency. Optimal tuning is achieved by adjusting the torque on the screws 25 a and 25 c to drive points 27 a and 27 c to lie in a horizontal fixed plane.
The auxiliary mass 17 is constructed and arranged to have a natural frequency that is substantially equal to the undesired frequency in the forcing frequency band and a flexural mode substantially identical to that of the housing-cover assembly 13 , 15 . The material of the base plate 19 and cover 23 , the weight of the ball bearings 21 , and the torque on the screws 25 a, 25 b, and 25 c are selected to provide a stiffness k am and a mass m am so that the ratio k am /m an =ω am is approximately equal to the oscillating frequency of the housing-cover assembly 13 , 15 as excited by the forcing frequency. Consequently, the vibrations of the assembly 13 , 15 are countered by the addition of the auxiliary mass 17 causing a significant reduction in the vibrations of the overall system.
Attaching the auxiliary mass as described above creates a zero motion zone (vibration node) at locations 24 a and 24 c respectively coupled to locations 27 a and 27 c. This is achieved by locating the auxiliary mass inherent nodal line 26 parallel to the nodal line 14 a of the housing 13 defined by the two points 29 and 27 b. The auxiliary mass is activated when the pad 29 on upper wall 13 a of the housing 13 establishes contact with the auxiliary mass and with the torque applications on the hardware 25 a, 25 b and 25 c. It should be recognized that the addition of the auxiliary mass assembly 17 to the housing 13 without a spacer pad at location 29 , results in a full surface-to-surface contact along the entire upper wall surface of 13 a. This tends to add the auxiliary mass m am directly to the housing-cover mass m 0 for a total combined system mass of (m total =m 0 +m am ) with negligible k am contribution such that ω am <<ω and β am ˜0 which yields an undesired application of vibration amplitude
x 0 =( P 0 /k )/[(1−ω 2/ ( k/m total )]
While the invention has been described in its preferred embodiments, it is to understood that the words that have been used are words of description rather than limitation and that changes may be made within the purview of the appended claims without departing from the true scope and spirit of the invention in its broader aspects. | A tunable mass coupled to a body subjected to forced vibrations that reduces the vibration amplitudes of the body in the forced vibration frequency band. The mass includes a container having a plurality of cavities with grooves in the lower surfaces and notched side walls. Each cavity is filled with spherical elements which are restrained by the grooves and notches. The tunable mass is constructed to respond in a spring like manner so that vibration frequencies of the mass are tunable to provide counter vibrations in the forced vibration frequency band. Vibration frequency amplitude reduction is provided by vibrations of the mass that are in phase opposition to the vibrations of the body. | 5 |
BACKGROUND OF THE INVENTION
[0001] 1. Technical Field
[0002] The present invention relates in general to a system and method for maintaining functionality during component failures. More particularly, the present invention relates to a system and method for providing component access alternatives to an application when one of the applications encounters an unavailable component.
[0003] 2. Description of the Related Art
[0004] Computer applications are becoming increasingly complex. In the process of becoming more complex, computer applications are also becoming more dependent upon outside components, such as databases and other applications. During a large application's operation, the application may launch other applications and access many databases. In a distributed computer system, an application may launch these components on servers that may be located in a different office complex.
[0005] A challenge found, however, is that components that an application depends may become unavailable. For example, an application may attempt to access a database and discover that the database is not responding possibly due to a database interface failure. When an application encounters an unavailable component, the application attempts to recover from the encounter, which typically involves attempting to access the same component a second time. If the application is unsuccessful, the application tends to take an “all or nothing” approach. Either the application completely restarts, or, if the failure is severe, an entire server or set of servers on which the application executes is restarted. In today's business environment where more and more businesses depend upon continuous availability of computer application systems, this is an invasive and time-consuming approach to managing application availability.
[0006] Another challenge is developing as systems evolve in support of the extremely dynamic nature of today's business environment. In order to fit this need, applications are becoming less aware of the computer infrastructure on which they run. Technologies such as Virtualization, Automated Provisioning of new servers in real time, and automated business process orchestration make it more difficult to develop component failure contingency plans in advance without a “flexible manager” function to address real outage situations as they arise.
[0007] What is needed, therefore, is a system and method for an application to continue operation when the application encounters an unavailable component by offering the application an alternative action to perform.
SUMMARY
[0008] It has been discovered that the aforementioned challenges are resolved by providing an application with alternative operating instructions when the application encounters an unavailable component. During application registration, a recovery engine generates a recovery plan for the application. The recovery plan includes recovery actions that correspond to each component that the application intends to access. When an application encounters an unavailable component, the recovery engine provides a recovery action to the application which instructs the application how to proceed, such as accessing a backup component. For example, if an application detects a specific database interface failure, the recovery engine may instruct the application to access a backup copy of the database, run in degraded mode without the database, or place database transaction requests onto a queue for future processing when the database recovers.
[0009] A first application sends a registration request that includes a profile to the recovery engine. The profile includes component links that the first application plans to access, such as a database. The recovery engine uses business rules to generate a recovery action for each component, and stores the recovery actions in a recovery plan.
[0010] The first application begins to execute, and sends a request to a component, such as component “X”, in an effort to access component X. For example, component X may be a database interface that has failed. In this example, component X does not send a response to the first application. As a result, the first application sends a “component alert” to the recovery engine, informing the recovery engine of component X's unavailability.
[0011] In turn, the recovery engine retrieves the first application's recovery plan and identifies a recovery action that corresponds to component X's unavailability. The recovery engine sends the identified recovery action to the first application, which instructs the first application to access an alternative component, such as a back-up component. The first application sends a request to the back-up component which, in turn, sends a response to the first application. In addition to sending the recovery action to the first application, the recovery engine stores a component identifier corresponding to component X in a tracking look-up table. The recovery engine uses the tracking look-up table during subsequent application registrations to identify unavailable components. In one embodiment, the recovery engine may also store the tracking look-up table in internal memory for faster data access.
[0012] The first application continues executing, and launches a second application. The second application sends a registration request to the recovery engine in order to register with the recovery engine. In turn, the recovery engine retrieves the business rules and begins to generate a recovery plan for the second application. During the registration process, the recovery engine identifies the availability of each component that the second application intents to access by looking-up each component in the tracking look-up table, as well as pinging each component. The recovery engine determines that the second application intends to use component X by detecting the corresponding component identifier in the tracking look-up table. The recovery engine generates and stores a recovery plan for the second application, and sends a recovery action to the second application that instructs the second application to access the back-up component instead of accessing component X. The first application and the second application continue to access the back-up component until they finish executing, or until they are instructed to start using component X once component X becomes available.
[0013] The foregoing is a summary and thus contains, by necessity, simplifications, generalizations, and omissions of detail; consequently, those skilled in the art will appreciate that the summary is illustrative only and is not intended to be in any way limiting. Other aspects, inventive features, and advantages of the present invention, as defined solely by the claims, will become apparent in the non-limiting detailed description set forth below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The present invention may be better understood, and its numerous objects, features, and advantages made apparent to those skilled in the art by referencing the accompanying drawings. The use of the same reference symbols in different drawings indicates similar or identical items.
[0015] FIG. 1 is a diagram showing a recovery engine generating recovery plans and providing recovery actions to applications;
[0016] FIG. 2 is a high-level diagram showing steps taken in generating a recovery plan and providing recovery actions to an application;
[0017] FIG. 3 is a detail level flowchart showing steps taken in registering an application;
[0018] FIG. 4 is a detail level flowchart showing steps taken in generating a recovery plan for an application;
[0019] FIG. 5 is a detail level flowchart showing steps taken in processing a recovery action that corresponds to an unavailable component; and
[0020] FIG. 6 is a block diagram of an information handling system capable of implementing the present invention.
DETAILED DESCRIPTION
[0021] The following is intended to provide a detailed description of an example of the invention and should not be taken to be limiting of the invention itself. Rather, any number of variations may fall within the scope of the invention which is defined in the claims following the description.
[0022] FIG. 1 is a diagram showing a recovery engine generating recovery plans and providing recovery actions to applications. Recovery engine 100 generates recovery plans that include recovery actions which correspond to particular components. When an application informs recovery engine 100 of an unavailable component, recovery engine 100 provides a recovery action to the application that corresponds to the component. For example, if an application detects a specific database interface failure, recovery engine 100 may instruct the application to access a backup copy of the database, run in degraded mode without the database, or place database transaction requests onto a queue for future processing when the database recovers.
[0023] Application A 105 sends registration request 110 that includes a profile to recovery engine 100 . The profile includes component links which application A 105 plans to access, such as a database. Recovery engine 100 retrieves rules 120 from rules store 115 that includes business rules for generating a recovery action (see FIG. 3 and corresponding text for further details regarding registration details). During registration, recovery engine 100 may ping the component links included in the profile, such as component X 140 , to verify that each component is available.
[0024] Recovery engine 100 generates a recovery plan for application A 105 , which includes a recovery action for each component link, and stores plan A 125 in data store 130 (see FIG. 4 and corresponding text for further details regarding recovery plan generation). Plan A 125 includes recovery actions which describe alternative actions for application A 105 to execute when application A 105 identifies an unavailable component. For example, if application A 105 fails to access a particular database, a recovery action may instruct application A 105 to access a backup database. Rules 115 and recovery plan store 130 may be stored on a nonvolatile storage area, such as a computer hard drive.
[0025] Once registered, application A 105 begins execution and sends request 135 to component X 140 in an effort to access component X 140 . For example, component X 140 may be a database interface. In this example, component X 140 is unavailable and does not send a response to application A 105 . As a result, application A 105 sends component alert 145 to recovery engine 100 , which informs recovery engine 100 of component X 140 's unavailability.
[0026] Recovery engine 100 retrieves plan A 125 from data store 130 and identifies a recovery action included in plan A 125 that corresponds to component X 140 's unavailability (see FIG. 5 and corresponding text for further details regarding component recovery processing). Recovery engine 100 sends recovery action 150 to application A 105 which instructs application A 105 to access an alternative component, such as back-up component X 160 . Application A 105 sends request 155 to back-up component X 160 which, in turn, sends response 165 to application A 105 . In addition to sending recovery action 150 to application A 105 , recovery engine 100 stores a component identifier corresponding to component X 140 in a tracking look-up table located in tracking store 148 . Recovery engine 100 uses the tracking look-up table during subsequent application registrations to identify unavailable components (see below for further details). In one embodiment, recovery engine 100 may also store the tracking look-up table in internal memory for faster data access.
[0027] Application A 105 continues executing, and sends launch 170 to application B 175 which launches application B 175 . Application B 175 sends registration request 180 to recovery engine 100 in order to register with recovery engine 100 . In turn, recovery engine 100 retrieves rules 120 from rules store 115 and begins to generate a recovery plan for application B 175 . During the registration process, recovery engine 100 identifies the availability of each component that application B 175 intents to access by looking-up each component in the tracking look-up table, as well as pinging the components. Recovery engine 100 determines that application B 175 intends to use component X 140 which has a corresponding component identifier in the tracking look-up table which indicates that component X 140 is unavailable. Recovery engine 100 generates and stores a recovery plan (e.g. plan B 185 ) and sends recovery action 150 to application B 175 that instructs application B 175 to access back-up component X 160 instead of component X 140 .
[0028] Application B 175 sends request 195 to back-up component X 160 which, in turn, sends response 199 to application B 175 . Application A 105 and application B 175 continue to access back-up component X 160 until they finish executing, or until they are instructed to start using component X 140 once component X 140 becomes available.
[0029] FIG. 2 is a high-level diagram showing steps taken in generating a recovery plan and providing recovery actions to an application. Processing commences at 200 , whereupon processing receives a registration request from application 205 , and stores the registration request in temp store 215 (step 210 ). The registration request includes a list of component links that application 205 plans to access. Temp store 215 may be stored on a nonvolatile storage area, such as a computer hard drive.
[0030] Processing registers application 205 and, during application registration, processing stores the component link information in data store 130 that identifies the operability of each component that is specified in the registration request. If one of the components is unavailable, processing sets a “component recovery flag” which indicates that a recovery action is required for an unavailable component (pre-defined process block 220 , see FIG. 3 and corresponding text for further details). Data store 130 is the same as that shown in FIG. 1 and may be stored on a nonvolatile storage area, such as a computer hard drive.
[0031] Once application 205 is registered, processing uses information gathered during the registration process to generate a recovery plan. Processing uses business rules that are retrieved from rule store 115 , as well as component information that is retrieved from data store 130 , in order to generate the recovery plan (pre-defined process block 230 , see FIG. 4 and corresponding text for further details).
[0032] A determination is made as to whether the component recovery flag was set during application registration, signifying that a recovery action is required for one of the components (decision 240 ). If the component recovery flag is set, decision 240 braches to “Yes” branch 242 whereupon the recovery action is identified and processed (pre-defined process block 270 , see FIG. 5 and corresponding text for further details). On the other hand, if the component recovery flag is not set, decision 240 branches to “No” branch 248 whereupon processing monitors components 255 and application 205 (step 250 ). For example, processing may monitor components 255 by invoking a “heartbeat” ping to each component to ensure that each component available, and processing may monitor application 205 by checking for component alerts sent from application 205 .
[0033] A determination is made as to whether there is an unavailable component (decision 260 ). If there is not an unavailable component, decision 260 branches to “No” branch 262 which loops back to continue to monitor the computer system. This looping continues until an unavailable component is detected, at which point decision 260 branches to “Yes” branch 268 whereupon processing identifies a recovery action corresponding to the unavailable component, sends the recovery action to application 205 , and logs the unavailable component in a look-up table located in tracking store 148 (pre-defined process block 270 , see FIG. 5 and corresponding text for further details).
[0034] A determination is made as to whether to continue recovery processing (decision 280 ). If recovery processing should continue, decision 280 branches to “Yes” branch 282 which loops back to continue to monitor the system. This looping continues until recovery processing should stop, at which point decision 280 branches to “No” branch 288 whereupon processing ends at 290 .
[0035] FIG. 3 is a detail level flowchart showing steps taken in registering an application. Application registration commences at 300 , whereupon processing retrieves the application's profile from temp store 215 and identifies whether the profile includes a start-up sequence (step 310 ). For example, the application may initialize the components it plans to access, and the application requires time to perform the initialization steps before the recovery engine accesses the components.
[0036] At step 320 , processing selects the first component link that is included in the profile, and looks-up the component link in a tracking look-up table located in tracking store 148 to identify whether the component has been logged as being unavailable. For example, if an application attempted to access the component and the component did not respond, the application sent a component alert to a recovery engine which, in turn, stored a component identifier corresponding to the component in the tracking look-up table in order to track the unavailable component (see FIG. 5 and corresponding text for further details regarding component identifier storage steps).
[0037] A determination is made as to whether the component has a corresponding component identifier located in the tracking look-up table (decision 330 ). If the first component has a corresponding component identifier in the tracking look-up table, decision 330 branches to “Yes” branch 332 whereupon processing stores the component link in data store 130 (step 365 ), and sets a component recovery flag that indicates that a recovery action is required for the unavailable component (step 370 ). On the other hand, if the component does not have a corresponding component identifier located in the tracking look-up table, decision 330 branches to “No” branch 348 .
[0038] A determination is made as to whether to ping the first component (step 340 ). For example, if a start-up sequence is specified, processing may be required to wait until the start-up sequence is complete before pinging the component. If processing should not ping the component, decision 340 branches to “No” branch 342 which loops back to wait to ping the components. This looping continues until processing should ping the component (i.e. the start-up sequence is complete), at which point decision 320 branches to “Yes” branch 348 and pings component 255 at step 350 . Component 255 is the same as that shown in FIG. 2 .
[0039] A determination is made as to whether component 255 responds to the ping (decision 360 ). If component 255 does not respond, decision 360 branches to “No” branch 362 whereupon processing stores the component link in data store 130 (step 365 ), and sets a component recovery flag (step 370 ). On the other hand, if component 255 responds to the ping, decision 360 branches to “Yes” branch 368 whereupon processing stores the component link in data store 130 at step 380 .
[0040] A determination is made as to whether there are more components to ping (decision 390 ). If there are more components to ping, decision 390 branches to “Yes” branch 392 whereupon processing selects (step 395 ) and processes the next component. This looping continues until there are no more components to ping, at which point decision 390 branches to “No” branch 398 whereupon processing returns at 399 .
[0041] FIG. 4 is a detail level flowchart showing steps taken in generating a recovery plan for an application. Processing commences at 400 , whereupon processing retrieves a first component link from data store 130 (step 410 ). Component links that correspond to the application were stored in data store 130 during the application's registration. For example, if the application is an automated teller machine, one of the component links would correspond to accessing a client account database with the intent to update the database in support of the ability to withdraw funds from a client's account (see FIG. 3 and corresponding text for further details regarding registration steps). Data store 130 is the same as that shown in FIG. 1 and may be stored on a nonvolatile storage area, such as a computer hard drive.
[0042] Processing retrieves business rules that correspond to the first component link from rules store 115 at step 420 . Using the example described above, if the client database is unavailable, a business rule may allow a user to withdraw up to $100 each day. Processing generates a recovery action using the retrieved business rules at step 430 , and stores the recovery action in data store 130 at step 440 . Using the example described above, a recovery action may instruct the application to store withdraws in a local storage area, and update the client database when the client database becomes available.
[0043] A determination is made as to whether there are more component links located in data store 130 to generate a recovery action (decision 450 ). If there are more component links, decision 450 branches to “Yes” branch 452 which loops back to retrieve (step 460 ) and process the next component link. This looping continues until there are no more component links to process, at which point decision 450 branches to “No” branch 458 whereupon processing returns at 470 .
[0044] FIG. 5 is a detail level flowchart showing steps taken in processing a recovery action that corresponds to an unavailable component. Processing commences at 500 , whereupon processing identifies an application that requires the recovery action (step 510 ). At step 520 , processing identifies the component that is deemed unavailable either from receiving a component alert from the application or from not receiving a ping response from the component.
[0045] Processing sends a message to system administrator 540 informing him of the unavailable component and which application is effected (step 530 ). At step 550 , processing retrieves a recovery plan that corresponds to the identified application from data store 130 . The recovery plan includes recovery actions that correspond to components that the identified application access (see FIG. 4 and corresponding text for further details regarding recovery plan generation). Data store 130 is the same as that shown in FIG. 1 .
[0046] At step 560 , processing identifies a recovery action included in the recovery plan that corresponds to the unavailable component. For example, if the unavailable component is a database, the recovery action may instruct an application to use a back-up database. Processing sends recovery action 150 to application 210 at step 570 . Recovery action 150 and application 210 are the same as that shown in FIGS. 1 and 2 , respectively.
[0047] Processing stores a “component identifier” in tracking store 148 at step 580 , which is used to identify unavailable components when other applications register (see FIG. 3 and corresponding text for further details regarding application registration). Tracking store 148 is the same as that shown in FIG. 1 . Processing returns at 590 .
[0048] FIG. 6 illustrates information handling system 601 which is a simplified example of a computer system capable of performing the computing operations described herein. Computer system 601 includes processor 600 which is coupled to host bus 602 . A level two (L2) cache memory 604 is also coupled to host bus 602 . Host-to-PCI bridge 606 is coupled to main memory 608 , includes cache memory and main memory control functions, and provides bus control to handle transfers among PCI bus 610 , processor 600 , L2 cache 604 , main memory 608 , and host bus 602 . Main memory 608 is coupled to Host-to-PCI bridge 606 as well as host bus 602 . Devices used solely by host processor(s) 600 , such as LAN card 630 , are coupled to PCI bus 610 . Service Processor Interface and ISA Access Pass-through 612 provides an interface between PCI bus 610 and PCI bus 614 . In this manner, PCI bus 614 is insulated from PCI bus 610 . Devices, such as flash memory 618 , are coupled to PCI bus 614 . In one implementation, flash memory 618 includes BIOS code that incorporates the necessary processor executable code for a variety of low-level system functions and system boot functions.
[0049] PCI bus 614 provides an interface for a variety of devices that are shared by host processor(s) 600 and Service Processor 616 including, for example, flash memory 618 . PCI-to-ISA bridge 635 provides bus control to handle transfers between PCI bus 614 and ISA bus 640 , universal serial bus (USB) functionality 645 , power management functionality 655 , and can include other functional elements not shown, such as a real-time clock (RTC), DMA control, interrupt support, and system management bus support. Nonvolatile RAM 620 is attached to ISA Bus 640 . Service Processor 616 includes JTAG and I2C busses 622 for communication with processor(s) 600 during initialization steps. JTAG/I2C busses 622 are also coupled to L2 cache 604 , Host-to-PCI bridge 606 , and main memory 608 providing a communications path between the processor, the Service Processor, the L2 cache, the Host-to-PCI bridge, and the main memory. Service Processor 616 also has access to system power resources for powering down information handling device 601 .
[0050] Peripheral devices and input/output (I/O) devices can be attached to various interfaces (e.g., parallel interface 662 , serial interface 664 , keyboard interface 668 , and mouse interface 670 coupled to ISA bus 640 . Alternatively, many I/O devices can be accommodated by a super I/O controller (not shown) attached to ISA bus 640 .
[0051] In order to attach computer system 601 to another computer system to copy files over a network, LAN card 630 is coupled to PCI bus 610 . Similarly, to connect computer system 601 to an ISP to connect to the Internet using a telephone line connection, modem 675 is connected to serial port 664 and PCI-to-ISA Bridge 635 .
[0052] While the computer system described in FIG. 6 is capable of executing the processes described herein, this computer system is simply one example of a computer system. Those skilled in the art will appreciate that many other computer system designs are capable of performing the processes described herein.
[0053] One of the preferred implementations of the invention is an application, namely, a set of instructions (program code) in a code module which may, for example, be resident in the random access memory of the computer. Until required by the computer, the set of instructions may be stored in another computer memory, for example, on a hard disk drive, or in removable storage such as an optical disk (for eventual use in a CD ROM) or floppy disk (for eventual use in a floppy disk drive), or downloaded via the Internet or other computer network. Thus, the present invention may be implemented as a computer program product for use in a computer. In addition, although the various methods described are conveniently implemented in a general purpose computer selectively activated or reconfigured by software, one of ordinary skill in the art would also recognize that such methods may be carried out in hardware, in firmware, or in more specialized apparatus constructed to perform the required method steps.
[0054] While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that, based upon the teachings herein, changes and modifications may be made without departing from this invention and its broader aspects and, therefore, the appended claims are to encompass within their scope all such changes and modifications as are within the true spirit and scope of this invention. Furthermore, it is to be understood that the invention is solely defined by the appended claims. It will be understood by those with skill in the art that if a specific number of an introduced claim element is intended, such intent will be explicitly recited in the claim, and in the absence of such recitation no such limitation is present. For a non-limiting example, as an aid to understanding, the following appended claims contain usage of the introductory phrases “at least one” and “one or more” to introduce claim elements. However, the use of such phrases should not be construed to imply that the introduction of a claim element by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim element to inventions containing only one such element, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an”; the same holds true for the use in the claims of definite articles. | A system and method for maintaining functionality during component failures is presented. During application registration, a recovery engine generates a recovery plan for the application. The recovery plan includes recovery actions that correspond to each component that the application intends to access. When an application encounters an unavailable component, the recovery engine provides a recovery action to the application which instructs the application how to proceed, such as accessing a backup component. The recovery engine tracks unavailable components and, when a subsequent application registers that intends to use an unavailable component, the recovery engine provides the subsequent application a recovery action, instructing the subsequent application how to proceed. | 6 |
FIELD OF THE INVENTION
This invention is generally related to the recovery of perfluorcompounds (PFCs). More specifically, this invention is related to a method and a system for the recovery of PFCs using condensation, preferably reflux condensation.
BACKGROUND OF THE INVENTION
PFCs are used in many manufacturing processes. In particular, they are widely used in the manufacture of semiconductor components. The nature of many of these manufacturing processes results in the atmospheric emission of PFCs. Being of high value and of detriment to the environment, it is advantageous to recover these emitted PFCs so that they may be reused.
Examples of PFCs are nitrogen trifluoride (NF 3 ), tetrafluoromethane (CF 4 ), trifluoromethane (CHF 3 ), hexafluoroethane (C 2 F 6 ) and sulfur hexafluoride (SF 6 ). In general, PFCs are fully fluorinated compounds of nitrogen, carbon and sulfur. CHF 3 is an example which is not fully fluorinated, but due to its similar chemical nature and application with other fluorine saturated PFCs, it is considered a PFC.
The manufacture of semiconductor components produces exhausts which typically comprise PFCs, non-PFC gases, particulate matter and a carrier gas. The flow from one process tool may be as high as 400 standard cubic feet per hour (scfh) and may comprise less than 1% PFCs.
Non-PFC gases may include hydrogen fluoride (HF), silicone tetrafluoride (SiF 4 ), silane tetrahydride (SiH 4 ), carbonyl fluoride (COF 2 ), carbon dioxide (CO 2 ), water (H 2 ), methane (CH 4 ) and carbon monoxide (CO). The carrier gas may be air, nitrogen or another inert gas. The majority of non-PFC gases and particulates are detrimental to PFC recovery processes and need to be removed in pre-purification processes. Some of the non-PFC gases, for example, carbon monoxide, may be inert to PFC recovery processes and may be allowed to pass through with the carrier gas.
The present invention recovers PFCs from the pre-purified carrier gas by condensation utilizing the large differences between the boiling points of PFCs and of various carrier gases. Table 1 gives the atmospheric boiling points and melting points of some common PFCs and nitrogen.
TABLE 1
Boiling
Melting
Compound
Point (K.)
Point (K.)
N 2
77
63
NF 3
144
66
CF 4
145
90
CHF 3
191
118
C 2 F 6
195
173
SF 6
209
222
Condensation of the PFCs is achieved by cooling the gas stream to temperatures below the dew points of the constituent PFCs. In order to achieve a high PFC recovery efficiency, it is necessary to cool the gas stream below the melting points of some of the lower volatility PFCs. Freezing of PFCs in the condenser is undesirable since this would reduce the efficiency of the condenser and prevent continuous operation. The instant invention contains several facets which prevent PFC freezing.
One, a reflux condenser is preferably used to effect the condensation of PFCs. The condensate in a reflux condenser flows counter-currently to the gas flow from where it came, and is therefore not necessarily further cooled. In general, however, a conventional condenser is applicable in this invention.
Two, this flow regime means that high volatility PFC condensate flows over the regions where low volatility PFCs condense. Low volatility PFCs with a tendency to freeze are soluble in these high volatility PFCs and freezing can be prevented.
Three, in the preferred embodiment, the concentration of high volatility PFCs in the gas stream is raised by recycling them in the system. This is achieved by separating the high volatility PFCs from the recovered PFC product, followed by re-addition up-stream. Raising the concentration of high volatility PFCs in the gas stream lowers the concentration of low volatility PFCs in the PFC condensate and prevents the PFCs from freezing.
Various solutions to recover PFCs from a carrier gas stream has been suggested, some mitigating the problem of PFC freezing when cryogenic means is used for recovery. However, none of the art teaches or suggests the present invention.
A prior method for recovering PFCs from the carrier gas is by condensation/dissolution as shown in U.S. Pat. No. 5,626,023. A solvent is added to the gas stream, which is then cooled to condense out the PFCs and any vaporized solvent. Low volatility PFCs with a tendency to freeze are soluble in the additive solvent. The additive solvent and PFCs are then separated by distillation and the additive solvent is reused. The solvent must be completely removed from the PFC product to prevent loss.
U.S. Pat. No. 5,540,057 provides for the removal of volatile organic compounds (VOCs) from a carrier gas by condensation of the VOCs in a reflux condenser. The VOC laden carrier gas passes up the shell side of a shell and a tube heat exchanger, and is then cooled along a continuous temperature gradient. The VOCs condense out to different extents at different levels and collect on special baffles in the shell side, which can direct a portion out of the condenser and allow a portion to drip back down the condenser as reflux. The cold cleaned carrier gas is then mixed with refrigerant at the exit to the shell side and passes down the tube side to effect the shell side cooling. Freezing of VOCs, specifically benzene, may be inhibited by the addition of a solvent, specifically toluene, to the gas stream.
U.S. Pat. Nos. 5,533,338 and 5,799,509 are examples of condensation freezing for condensing PFCs against a cryogenic fluid. The freezing of low volatility PFCs occurs due to the low temperatures required for high efficiency condensation of the high volatility PFCs. This method is disadvantageous because it is necessary to periodically defrost the frozen PFCs for removal. This results in low refrigeration efficiencies and requires duplicate equipment in order to maintain continuous operation.
Membrane permeation recovers the PFCs from the carrier gas through the differences in membrane permeability. The gas stream is contacted with the feed side of a specific membrane, which allows the carrier gas to preferentially permeate while the PFCs are retained. High separation efficiencies require the use of multiple membranes. PFCs have different permeation characteristics and vary in recovery efficiencies.
Adsorption recovers PFCs from the carrier gas. The gas stream is contacted with an adsorbent which removes the PFCs. The PFCs are then desorbed and removed from the adsorbent bed with a sweep gas. The sweep gas results in a low concentration PFC product. Furthermore, adsorption processes do not have the flexibility to adjust to the large changes in PFC concentrations and carrier gas flow rates which typify gaseous effluent streams.
Yet another PFC recycling method is the energy intensive process of incineration. The gas stream is heated to a high temperature, which prevents emission of the PFCs. Decomposition gases such as hydrogen fluoride and nitrogen oxides are then removed from the flue gas.
It is desirable that PFC recovery systems treat the exhaust from small semiconductor manufacturing tool clusters rather than whole manufacturing facilities. If one system fails, only a fraction of the manufacturing tools are affected. The present invention is therefore primarily intended to treat the exhaust from a small number of tools. However, it may also be scaled-up to treat the exhaust from an entire semiconductor manufacturing facility. It is also an object of this invention to mitigate the problem associated with PFC freezing, while recovering them from a carrier gas stream by cryogenic condensation.
SUMMARY OF THE INVENTION
This invention is directed to a system for recovering PFCs using condensation, preferably reflux condensation. A condenser provides indirect heat exchange from a PFC-containing gaseous stream to effect liquefaction into a PFC-containing condensate and a carrier gas stream. A mass transfer unit is used to fractionate the PFC-containing condensate into a high volatility PFC stream and a PFC product.
This invention is also directed to a method for recovering PFC using condensation, preferably reflux condensation. A PFC-containing feed stream is passed into a condenser to effect liquefaction into a PFC-containing condensate and a carrier gas stream. Also, the PFC-containing product is passed into a mass transfer unit to fractionate the PFC-containing condensate into a high volatility PFC stream and a PFC product.
DETAILED DESCRIPTION OF THE DRAWINGS
Other objects, features and advantages will occur to those skilled in the art from the following description of preferred embodiments and the accompanying drawings, in which:
FIG. 1 is a schematic diagram of recovery of PFCs in this invention.
FIG. 2 is a graph showing the condensate composition at various stages in a reflux condenser of this invention.
DETAILED DESCRIPTION OF THE INVENTION
As used herein, the term “high volatility PFCS” means one or more PFCs having an atmospheric boiling point below 150 K. Examples include tetrafluoromethane (CF 4 ) and nitrogen trifluoride (NF 3 ).
As used herein, the term “low volatility PFCs” means one or more PFCs having an atmospheric boiling point above 150 K. Examples include trifluoromethane (CHF 3 ), hexafluoroethane (C 2 F 6 ) and sulfur hexafluoride (SF 6 ).
As used herein, the term “indirect heat exchange” means the bringing of two fluid streams into heat exchange relation without physical contact or intermixing of the fluids between each other.
As used herein, the term “condenser” describes a vessel providing indirect heat transfer from a gaseous flow so as to effect the liquefaction of a portion of that flow.
As used herein, the term “condensate” describes a liquefied gas.
As used herein, the term “reflux condenser” describes a condenser wherein at least a portion of the condensate is forced to contact a hotter heat transfer surface than the one which effected its condensation. This re-heating causes at least a portion to be re-evaporated. This is easily effected by cooling an ascending gas stream. The condensate then descends and is warmed. The reflux condenser is preferred, and the general use of a condenser is contemplated in this invention.
As used herein, the term “reflux condensation” describes condensation carried out in a reflux condenser.
As used herein, the term “rectification column” describes a distillation or fractionation zone wherein liquid and vapor phases are counter-currently contacted to effect separation of a fluid mixture. A rectification column is preferred, but the general use of a mass transfer unit which may perform a similar function as the rectification column is contemplated in this invention.
Turning now to FIG. 1, which is a schematic flow diagram, of a preferred embodiment of the system in this invention. Warm gaseous feed stream 10 consists of a carrier gas, high volatility PFCs and low volatility PFCs, pressurized to approximately 95 psia. Particulate impurities and non-PFC gases such as hydrogen fluoride and fluorine will have been removed in a pre-purified stage. Stream 10 enters at elevated pressure after being compressed during the pre-purification stage. Pressure swing adsorption for example, requires pressurization of the gas stream. Other adsorption process, including thermal swing adsorption in the higher pressure level, are applicable. Pressurization is also found to aid separation of the PFCs from the carrier gas and reduces the size of the process equipment. Freezing points of individual PFCs will also be depressed at elevated pressure.
Stream 10 is cooled by indirect heat exchange with refrigerant stream 34 in heat exchanger 12 . Stream 10 is cooled to a temperature above that at which PFCs start to condense, in either liquid or solid form. It is important that PFCs do not freeze in heat exchanger 12 because there is no means for removing frozen PFCs.
The cooled gaseous feed stream 14 then exits heat exchanger 12 and enters condenser 18 , preferably a reflux condenser, where it combines with high volatility PFC stream 40 . In the preferred embodiment stream 40 is a liquid. It will also have a significantly lower temperature than stream 14 . This causes stream 40 to flash off such that the resulting mixed stream 16 attains a temperature lower than that of stream 14 . The temperature of stream 16 should be approximately that at which PFCs start to condense out. Addition of stream 40 to stream 14 results in mixed stream 16 having a greater high volatility PFC concentration than stream 14 .
Stream 16 is cooled counter-currently in condenser 18 by indirect heat exchange with cold refrigerant stream 32 . Cooling causes the PFCs to condense and flow out counter-currently to stream 16 , forming PFC condensate stream 22 . Low volatility PFCs such as hexafluoroethane and sulfur hexafluoride condense out towards the warmer end of the condenser 18 , and have a tendency to condense out as solids because they are cooled below their melting points. High volatility PFCs such as carbon tetrafluoride and nitrogen trifluoride condense out towards the colder end of the condenser and will not condense as solids since their melting points are not reached. It is a feature of the operation of condenser 18 , that the high volatility PFCs wash over the warmer end of the condenser and act as solvents towards the low volatility PFCs. Freezing of the low volatility PFCs is therefore inhibited. It is a further feature of this embodiment that stream 40 is added to stream 14 to increase the amount of high volatility PFCs with respect to low volatility PFCs. Addition of stream 40 also stabilizes the PFC composition and concentration in condenser 18 . This allows condenser 18 to operate under temperature conditions which more closely approximate to steady state, and aid the process control.
Cold carrier gas stream 20 leaves condenser 18 having been treated to remove PFCs. Liquid cryogen stream 24 is added to stream 20 via control valve 26 to produce stream 28 . The carrier gas will more usually be nitrogen gas and the liquid cryogen will more usually be liquid nitrogen. The rate of addition of stream 24 is determined by the refrigeration requirements in heat exchanger 12 and condenser 18 . Stream 20 will more usually be close to the dew point of the carrier gas in order to condense sufficient of the high volatility PFCs and as such, addition of stream 24 , will not usually cause stream 24 to completely vaporize. Stream 28 will therefore usually be two phase. Stream 28 passes through throttle valve 30 to form refrigerant stream 32 . The expansion causes a drop in temperature, the required degree of which is determined by the cold end temperature difference of condenser 18 and controlled by the pressure drop through throttle valve 30 . Stream 32 passes through condenser 18 , warms against mixed stream 14 and exits at the bottom of condenser 18 , as stream 34 . Stream 34 then passes to heat exchanger 12 to effect the cooling of stream 10 . Warm refrigerant stream 36 exits heat exchanger 12 . A portion of stream 36 may be used to regenerate adsorption beds in the pre-purification stage. It is also advantageous to use a portion as addition to the semiconductor tool exhaust to maintain the volumetric flow rate in the PFC recovery system constant.
Stream 22 passes to mass transfer unit 38 , preferably a rectification column, where high volatility and low volatility PFCs are separated preferably by cryogenic rectification. At the top of mass transfer unit 38 , stream 40 is formed and is recycled by adding to stream 14 at the condenser inlet. Stream 40 will also contain carrier gas that was condensed in condenser 18 during PFC removal. Mass transfer unit 38 therefore also raises the PFC concentration efficiency of the system. At the bottom of mass transfer unit 38 , liquid PFC product 42 is formed. Under steady state conditions, with 100% PFC recovery, the mass and relative proportion of PFCs entering the system in stream 10 will equal the mass and relative proportion of the PFCs leaving the system in stream 42 .
In another embodiment, addition of stream 40 may take place at points other than at the condenser inlet, such as into stream at any point in condenser 18 , into stream 16 , such that it flows back down as a liquid into condenser 18 , into stream 14 , prior to condenser 18 , directly into heat exchanger 12 and anywhere prior to heat exchanger 12 , including the pre-purification stage. Stream 40 may also be two phase or entirely gaseous.
Another embodiment does not require the use of stream 40 . Consequently, stream 22 is collected as product. Mass transfer unit 38 is not necessary. This embodiment is particularly applicable where stream 10 comprises enough high volatility PFCs to ensure that the low volatility PFCs do not freeze in condenser 18 .
Other types of condensers may be used to carry out the condensation of the PFCs, where stream 40 is used to prevent freezing in the condenser.
Certain types of PFCs may be used as solvents. For example, low volatility PFCs that do not have a high vapor pressure at their freezing point. These include trifluoromethane (CHF 3 ) and octafluoropropane (C 3 F 8 ).
Mass transfer unit 38 is used to separate the high volatility PFC from the PFC product. Other than a rectification column, various devices may be used, such as a dephlegmator. Also different means of adding refrigeration to heat exchanger 12 and/or condenser 18 may be used. This includes: one, indirect heat transfer with a cryogen such as liquid nitrogen. Two, mechanical refrigeration produced by a vapor compression cycle utilizing a working fluid which is a mixture of atmospheric gases, hydrofluorocarbons and/or PFCs. Three, mechanical refrigeration produced by the turbo expansion of dry air, nitrogen, argon or mixtures of the same. Four, refrigeration obtained from a pulse tube refrigerator, preferably with the input work to pulse tube provided by a linear motor-compressor. Also it may be convenient to expand cold carrier gas stream 20 through throttle valve 28 , prior to adding refrigeration.
Where heat exchanger 12 and condenser 18 are one unit, it is appropriate to carry out condensation in the conventional manner without reflux action.
Multiple condensers, or a condenser with multiple liquid outlets to produce multiple PFC condensate products may be used.
It is also contemplated to operate the system at pressures above and below about 95 psia. For pressure swing adsorption applications, the pressure range of from about 80 psia to about 200 psia, preferably from about 90 psia to about 125 psia, and most preferably at about 95 psia is desirable. For a thermal swing adsorption application, a substantially higher pressure range is used.
EXAMPLE
Stream 10 comprises nitrogen carrier gas with 1,000 ppm CH 4 , 2,000 ppm C 2 F 6 , and 500 ppm SF 6 , having been treated to remove non-PFC gases such as HF, F 2 , H 2 O) and CO 2 . Stream 10 has a pressure of 94 psia and a temperature of 288 K.
Stream 10 is cooled to 165 K in heat exchanger 12 to form stream 14 , and then passes into condenser 18 . Stream 40 , comprising CF 4 and a portion of nitrogen carrier gas, is flashed into stream 14 at the inlet to the condenser, raising the concentration of CF 4 in the resultant stream 16 to 18,200 ppm and lowering the temperature to 157 K.
Stream 16 is cooled in condenser 18 so that the PFCs condense to form stream 22 and the carrier gas exits as stream 20 . To ensure high removal efficiency of the PFCs, a portion of the nitrogen carrier gas also condenses in the reflux condenser. At 93 psia, this occurs at 97.3 K. Stream 20 comprises nitrogen with 5 ppm CF 4 . FIG. 2 shows the composition of the liquid condensate at various stages in the reflux condenser. Stage 1 corresponds to the top of the condenser and stage 5 , to the bottom, and this is represented by the x-axis. The y-axis represents the mole fraction for each of the compounds.
In this example, stream 22 is pumped into rectification column 38 , where it is separated to form stream 40 and stream 42 . At 95 psia, stream 16 has a temperature of 125 K and comprises 87.9 mol % CF 4 and 13.1 mol % nitrogen. At 96 psia, stream 42 has a temperature of 209 K and comprises 28.6 mol % CF 4 , 57.1 mol % C 2 F 6 and 14.3 mol % SF 6 .
The recovery efficiencies of CF 4 , C 2 F 6 , and SF 6 are 99.5%, 100% and 100% respectively. The PFC product contains 1 ppm nitrogen carrier gas. A 2,000 scfh system consumes approximately 50 lb/hr of liquid nitrogen refrigerant
Specific features of the invention are shown in one or more of the drawings for convenience only, as each feature may be combined with other features in accordance with the invention. Alternative embodiments will be recognized by those skilled in the art and are intended to be included within the scope of the claims. | This invention is directed to a method, and a system therefor, for recovering PFC using condensation by passing a PFC-containing feed stream into a condenser, preferably reflux condenser, to effect liquefaction into a PFC-containing condensate and a carrier gas stream, and passing the PFC-containing product into a mass transfer unit to fractionate the PFC-containing condensate into a high volatility PFC stream and a PFC product. | 8 |
BACKGROUND OF THE INVENTION
The auxiliary draft device for a fireplace comprising the present invention is directed at improving the efficiency of consumption of fuel in the fireplace and also to reduce or prevent the removal of warm air in the room in which a fireplace is located which, under normal circumstances with conventional fireplaces, is required to provide some, if not most of the air required to cause the fuel of the fireplace to burn.
A fireplace of conventional design requires an inflow of air which, in turn, when heated, is lost up the chimney. Further, such air exhaust from a room causes a negative pressure inside the room and any adjoining rooms, thus causing cold air to flow in at any possible opening in the building in which the room is located. Obviously, such ingress of cold air causes unnecessary fuel consumption, particularly since it acts adversely to the conventional home heating system and requires a greater amount of heat from said system to counteract the cold air drawn in by such circumstances.
In modern homes which are highly effectively insulated, as well as in efficiently heated homes, a conventional fireplace is becoming prohibitively wasteful in terms of fuel consumption due to wasted warm air being consumed from the room by the fuel in the fireplace and resulting in drafts across floor areas. As a result of this, particularly in view of the present high cost of fuel, the use, if not the installation, of fireplaces is being reduced, although there is the possibility of greater use of the same in areas of abundant wood being available and the cost thereof being appropriately less than that of fuel oil and the like.
In such normal or conventional fireplaces, the air flow for igniting the fuel is through the front opening of the fireplace, then through the combustion chamber and up through the rear area of the combustion chamber, past the damper and into the smoke chamber and then up the flue. For greatest efficiency, such path of air flow is critical and any system that disrupts the even flow of such air results in inefficient burning of fuel and, under certain circumstances, causes the discharge of smoke into the surrounding room areas.
As described hereinafter, the present invention involves the use of an air curtain supplied across the front face of the fireplace opening. The principle of air curtains which effect separation of two chambers or spaces used at the entrance of stores, refrigerator rooms, and the like to prevent air flow between such spaces is well-known and proven. Providing such an air flow up across the front of a fireplace opening similarly tends to effectively separate and prevent any appreciable amount of the warm room air from the fireplace chamber while providing air to achieve combustion of the fuel in the fireplace and thereby effectively reduce air consumption from the surrounding room area.
The invention also includes the provision of an opening through a room wall adjacent the fireplace in order to permit the introduction of outside air to the fireplace. In this regard, it also is known that any opening through an outside wall of a building can be a source of unwanted cold air leaking into the building unless such an opening is closed at the outside wall.
Further, it also is quite well established that combustion within a fireplace chamber that is closed, for example, by glass doors across the face of the chamber frequently causes smoking of the glass with soot and tar due to the rolling of the smoke against the glass when the air flow is restricted. Further, it also is known that the burning of a fireplace of conventional configuration with glass doors across the front thereof, when closed, may cause overheating of the glass front, especially if the air intake vents which usually are provided in the lower portion of glass door assemblies and units are not open. But, when they are open, there obviously is a continual consumption of interior warm air by the fireplace obtained from the room and other vicinities near the fireplace from which such air is obtained.
It also is known to provide combustion air for fireplaces from sources outside of the room, such as exterior air, and also provide means for regulating the flow of such air to the fireplace. By way of example, prior U.S. Pat. No. 4,106,475, to Mayes, dated Aug. 15, 1978, and U.S. Pat. No. 4,137,895 to Bittinger, dated Feb. 6, 1979, respectively show the introduction of outside air directly to the lower part of the combustion chamber, and directed radially and inward toward the lower part of said combustion chamber. However, systems that direct auxiliary air, such as outside air, either at the back of the combustion chamber or immediately beneath the same, cause an intense blowing effect at the base of the fire which not only frequently causes more rapid consumption of fuel than otherwise, but also effects a disruption of the natural flame and fire patterns which are pleasing in appearance and thus, detract from the desirability and pleasure of a normal fireplace fire. These difficulties are obviated by the present invention, details of which are as follows:
SUMMARY OF THE INVENTION
It is one of the principal objects of the present invention to provide an auxiliary draft device and system for installation at the front face of a fireplace opening for purposes of drawing air from the outside of the building in which the fireplace is located and direct the same as a vertical curtain of air across the front face of the fireplace, thereby tending to minimize the drawing of air for combustion purposes from the room and adjacent area in which the fireplace is located, without impairing the normal aesthetic appearance of the fire or increasing the rate of consumption thereof due to the fact that the curtain of air from the outside atmosphere is entirely supplemental and acts as a substitute for air which, in normal fireplace installations, is drawn from the immediate room vicinity.
It is another object of the invention ancillary to the foregoing object to provide in the auxiliary draft device an air-distributing shell formed of sheet metal of rigid nature which is supported horizontally and solely upon a floor surface directly in front of and extending across the front opening of the fireplace adjacent the hearth, said shell having a top wall in which a plurality of openings are provided through which air obtained from outdoors is directed vertically upward to form said aforementioned air curtain which is substantially of uniform density entirely across said fireplace opening.
A further object of the invention is to provide said aforementioned air-distributing shell, in plan view, with a width which decreases from one end toward the other and said draft device also including at said one end an extension shell which operates as a plenum chamber, said plenum chamber extending transversely to said one end of said air-distributing shell, along one side of the fireplace and also communicating with horizontal conduit means leading from said plenum chamber to the outside atmosphere by means of an appropriate opening through the wall of the building in which the fireplace is located.
Still another object of the invention is to provide on the outer end of said horizontal conduit, an adjustable exterior damper having actuating means extending from the damper and having a manually-operable handle or the like readily accessible at the front of the fireplace for controlling the extent of opening of the damper to permit the inlet of outside air to the fireplace.
Another object of the invention ancillary to the immediately foregoing object is to arrange the air outlet openings in the top wall of the air-distributing shell in such manner that they are arranged for suitable spacing from the larger end of said shell toward the smaller end for purposes of providing a vertically moving air curtain of essentially uniform density across the entire front face of the fireplace opening.
A still further object of the invention is to arrange the components of the auxiliary draft device and system in the form of individual, connectable components which are readily assembled for installation in conjunction with a fireplace and said components being adapted to be merchandised in kit form, the detachability particularly of the air-distributing shell from the extension shell which serves as a plenum chamber permitting relatively easy removability of the air-distributing shell from the plenum chamber, especially for purposes of facilitating the removal of ashes from the fireplace, it also being a feature of the auxiliary draft device that the air-distributing shell is forward of the location of fuel in the combustion chamber of the fireplace, whereby at least in normal use, the ashes of the fuel will not drop upon said air-distributing shell and the relatively forward position of said air-distributing shell adjacent the front face of the fireplace minimizing the possibility of damage to said shell by the heat generated in the combustion chamber.
Still another object of the invention is to provide an auxiliary supply of outdoor combustion air to the fireplace, particularly a fireplace in which glass doors are used across the front face of the fireplace, the air-distributing shell of said draft device being immediately adjacent the inner surface of said glass doors so as to distribute the vertical air curtain upwardly adjacent the inner surface of the glass doors and thus, prevent the same from becoming excessively hot and also minimizing the accumulation of smoke and tar thereon.
Details of the foregoing objects and of the invention are set forth in the following specification and illustrated in the accompanying drawings comprising a part thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front elevation of a conventional fireplace adjacent one wall of a room shown fragmentarily, said fireplace being the type having glass doors across the front face thereof, part of one door being broken away to show details of the invention.
FIG. 2 is a horizontal sectional view of the fireplace installation shown in FIG. 1, as seen on the line 2--2 thereof, and illustrating in horizontal section a portion of the horizontal conduit means leading to the exterior of the building in which the fireplace is located.
FIG. 3 is a fragmentary vertical sectional view of the fireplace shown in FIGS. 1 and 2, as seen on the line 3--3 of FIG. 2.
FIG. 4 is a fragmentary vertical sectional view of a portion of the air-inlet end of conduit means of the device located in the lower left-hand corner of FIG. 3,
FIG. 5 is a vertical sectional view of the conduit means shown in FIG. 4, as seen on the line 4--4 thereof.
FIG. 6 is a fragmentary horizontal sectional view of a portion of the device shown in the lower right-hand corner of FIG. 2 and illustrating a slightly different embodiment of installation of manually-operable regulating means for the outdoor shutter shown in FIGS. 3 and 4.
FIG. 7 is a fragmentary vertical front view of a portion of the details shown in FIG. 6, as seen on the line 7--7 thereof.
FIG. 8 is a perspective view of the air-distributing shell shown in plan view in FIG. 2 adjacent the front face of the fireplace illustrated therein.
FIG. 9 is a side view, partly in vertical section, of another embodiment of the air inlet conduit of the device and illustrating a further embodiment of shutter-adjusting means from that shown in FIGS. 2, 4, 6 and 7.
FIG. 10 is a vertical sectional view, as seen on the line 10--10 of FIG. 9.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring particularly to FIGS. 1-3, an exemplary wall 10, such as the outside wall of a building, is illustrated for purposes of affording a background for the exemplary fireplace 12, which is illustrated as being constructed of brick masonry, and having a fireplace opening 14 in the front face of the fireplace 12. In the illustration, according to FIGS. 2 and 3, it will be seen that the wall 10, which is considered to be an outside wall, consists of an exemplary brick sub-wall 16 against which studs 18, see FIG. 3, are disposed and to which exemplary exterior sheathing 20 is applied.
The actual fireplace 12 has a chimney wall 22, see FIG. 3, of conventional brick which extends above a substantially U-shaped firebrick wall 24, suitably shaped to provide a smoke shelf 26, shown in FIG. 3, which is in cooperation with an adjustable damper 28, controlled by a manual actuator 30, the exemplary front face of the fireplace 12 also having a vertical brick wall 32. In the exemplary illustration shown in FIGS. 1-3, the fireplace opening 14 also is covered by a pair of glass doors 34, especially for purposes of showing the adaptability of the present invention to fireplaces to which glass doors have been applied, or otherwise.
Referring to FIGS. 1-3, the fireplace 12 also is provided with a conventional hearth 36 which usually is substantially at floor level or slightly thereabove and, especially for purposes of this invention, is considered to be the equivalent of a floor.
The auxiliary draft device of the present invention comprises essentially three related components which respectively are the sheet metal air-distributing shell 38, the extension shell or plenum chamber 40, and the horizontal inlet conduit 42. Additional details related to these three components are described in detail hereinafter. Said three components also are readily detachably connectable and, in particular, the air-distributing shell 38 is detachable from the extension shell 40, especially for purposes of replacing the same in the event such replacement ever is necessary, and more particularly, to render the distributing shell 38 removable from in front of the combustion cavity 44 in which, for example, the fireplace fuel, such as logs, and and irons are mounted as shown in phantom, particularly in FIGS. 1-3. From FIG. 2, in particular, it will be seen that the air-distributing shell 38 is supported upon the floor of the combustion cavity 44 which is preferably in the same plane as the hearth 36 and/or the floor of the room in which the fireplace is installed. Such detachability of the distributing shell 38 facilitates the removal of ashes from the floor of the combustion cavity 44.
Also, from FIGS. 2, 6 and 8, it will be seen that the distributing shell 38, which preferably is made from a suitable gage of sheet metal capable of resistance to any extensive damage from the heat of the combustion of the fuel in the fireplace cavity 44, is wider at the inlet end 46 than at the opposite end 48, which is closed. The purpose of such shape is to render the distribution of air substantially uniform between the opposite ends of the shell 38. Such air distribution occurs from a plurality of holes 50 which are formed in the top wall 52 of the shell 38 which preferably is horizontal. Particularly from FIG. 8, it will be seen that the shell 38 also is substantially rectangular in cross-section and, by way of example, without restriction, a suitable vertical dimension of the shell is approximately four inches. Further, to facilitate the uniform distribution of air between opposite ends of the shell 38, it will be seen that the holes 50 are a little more closely spaced adjacent the inlet end 46 of the shell 38 than at the opposite end thereof for suitable arrangement of the same in order that the holes 50 are arranged as closely as feasible to the front wall 54 of the shell 38. As a result of this, outside or outdoor air which enters through the inlet end 56 of inlet conduit 42, as viewed in FIG. 2, passes along the conduit to the plenum chamber 40 and from there, it enters the distributing shell 38 through the inlet end 46 thereof and exits substantially vertically through the holes 50 in such manner that a cold air curtain of substantially uniform density rises vertically from the shell 38, completely across the front face of the combustion cavity 44 of the fireplace, where it becomes available for combustion of the fuel and additionally serves the important function of minimizing the consumption of warm air from the room in which the fireplace is located, thereby at least greatly preventing the consumption of such warm air by the fireplace and thereby not burdening the conventional heating means of the room where the fireplace is installed.
The passage of such cool or cold outdoor air as aforesaid is induced primarily by the normal draft effected by the combustion of fuel in the fireplace cavity 44 which rises upwardly through the damper opening, when the damper 28 is open, and thence upwardly through the flue 58, as readily can be visualized from FIG. 3. Further, particularly in the event the fireplace includes glass doors 34, for example, especially if said doors are closed, the outdoor air furnished by the aforementioned means, especially the air-distributing means 38, is highly effective to supply the needed combustion air for the fuel, and by virtue of the upwardly rising curtain of such air immediately adjacent the inner surfaces of the doors 38, the possibility of such doors accumulating smoke stain and tar, as occurs in many types of glass doors associated with conventional fireplaces, is substantially eliminated. Another essential feature of the present invention comprises the control means by which the inlet of outside air enters the horizontal inlet conduit 42. Several embodiments of operating means for said control means are included and are described below. Both of them are associated with a shutter member 60 which is attached to the exterior wall face of the house, such as sheathing 20 as shown in FIGS. 3 and 4. The shutter 60 operates in the nature of a damper and preferably is pivoted at the upper edge thereof so that, when open to any desired degree, it will serve as a shield for the inlet of inclement weather. To prevent the ingress of undesired items of animal or insect nature, the inlet end 56 of the conduit 42 also preferably includes a screen barrier 62, shown in exemplary manner in FIG. 4.
One of the several embodiments of actuating means for the shutter member 60 is illustrated in FIGS. 2-7 and comprises a rotatable rod 64, which extends centrally within inlet conduit 42 for the entire length thereof as best shown in FIG. 2, and one end, designated as the inner end 66, is threaded, as shown in FIGS. 2, 3 and 6, for engagement with a fixed nut 68 positioned on the inlet end of a sleeve 70, which, as shown in FIGS. 2 and 6, extends through the brick facing 12, for example, of the fireplace for rotatable actuation by one of several types of manually operable elements, such as the crank 72 shown in FIGS. 2 and 3, or the rotatable knob 74, shown in FIGS. 6 and 7. The knob 74, for example, preferably is located in a recess 76, such as shown in FIGS. 6 and 7 to render the same less obtrusive than the crank 72, for example. Rotation of either the crank 72 or knob 74 relative to the fixed nut 68 moves the rod or shaft 64 axially for purposes of actuating the outer end 78 of rod 64 which engages any suitable means on shutter member 60, such as an angular flange 80 for purposes of controlling the closed position of shutter member 60, as shown in full lines in FIG. 4 or a desired degree of opening of the shutter, as shown in phantom in FIG. 4. Operative positioning of the outer end 78 of rotatable rod 64 within the inlet conduit 42 is achieved by a fixed bearing sleeve 82, see FIGS. 4 and 5, which is supported by appropriate spider members 84.
To prevent the inlet of outdoor air to the inlet conduit 42 when the shutter member 60 is closed, as shown in full lines in FIG. 4, the inner surface thereof may be suitably provided with appropriate gasket-type sealing means around the perimeter or across the entire inner face thereof for purposes of abutting the terminal end of the inlet conduit 42.
The additional embodiment of actuating means for the shutter member 60 is illustrated in FIGS. 9 and 10, in which the conduit 42 may be circular, if desired, or particularly as shown in FIG. 10, it may be rectangular in cross-section. As in the preceding embodiment, the shutter member 60 is pivotally connected at its upper end to the outer wall of a house or building and a rotatable rod 86 extends for the full length of the inlet conduit 42. The inner end has an actuating knob 88 connected thereto, said inner end of the rod also being supported in a bearing sleeve 90 mounted in the front brickwork face of the fireplace 12. The outer end of the rod 86 extends through suitable openings in a pair of longitudinally spaced, transverse supporting bars 92, which are fixed within the interior of the conduit 42. Said outer end of the rod 86 is provided with threads 94 which match a threaded nut 96, which is fixed to a longitudinal bar 98, which slides along the upper surfaces of the supporting bars 92 as the rod 86 is rotated relative to the nut 96. Longitudinal movement of the rod 86 is prevented by means of a pair of nuts or other abutment means 100 which are fixed to the rod 86 respectively adjacent the outermost surfaces of the supporting bars 92. A link 102 is pivotally connected respectively at its opposite ends to the outer end of bar 98 and a lug or clevis 104 is fixed to the inner surface of the shutter member 60 in spaced relation to the pivot on the upper end of the shutter member 60, as clearly shown in FIG. 9.
From this description, it will be seen that, as the knob 88 is rotated in opposite directions, it respectively will move the shutter member 60 between fully closed and a desired open position for purposes of effecting the regulation of ingress of outdoor air to the conduit 42 and thence to the air-distributing shell 38.
From the illustration shown in the drawings, it can be visualized that utilization of the auxiliary draft device comprising the invention is best undertaken when building or installing a new fireplace, particularly for purposes of incorporating the horizontal inlet conduit 42 within the masonry of one sidewall, for example, of the fireplace 12 and also for installing the extension shell and plenum chamber 40 within one side firebrick wall 24 of the fireplace. However, when it is desired to install such a device in existing fireplaces, it may be necessary to make limited revisions or changes in the actual shaped and construction of the air-distributing shell 38, extension shell and plenum chamber 40, and horizontal inlet conduit 42, for purposes of minimizing the formation of appropriate openings in the masonry of the fireplace and the firebrick wall thereof which should be adequate to accommodate the aforementioned elements, particularly to dispose the air-distributing shell 38 across the front face of the combustion chamber 44 of the fireplace at the floor level thereof. Especially if no glass doors are desired or actually are mounted upon the existing fireplace, the distributing shell 38 may be disposed somewhat forwardly of the position thereof shown in FIG. 2, for example, and actually rest upon the hearth 36, whereby especially the installation of the air-distributing member 38 will require no modification of the floor of the combustion cavity 44 or the hearth 36, as is necessary in certain prior art auxiliary air-distributing mechanism and in particular, the aforementioned U.S. Pat. Nos. 4,106,475 and 4,137,895.
From the foregoing, it will be seen that the present invention provides a relatively simple and durable auxiliary draft device for a fireplace which can be installed either in new or existing fireplaces with a minimum of adaptation being required, and in particular, the air distribution provided by said device develops a curtain of air entirely across the front face of the combustion chamber which may be either the open type or one that is provided with glass doors, such curtain of auxiliary outdoor air minimizing, if not preventing, any appreciable amount of warm air of the adjacent room entering the combustion zone of the fireplace, such curtain of air also, when employed with a fireplace having glass doors thereon, minimizing, if not eliminating, the occurrence of smoke and tar deposits upon the inner surface of the glass doors, the overall objective of the device being to also render the combustion of fuel economical and in a manner to prevent the occurrence of smoke or swirling of the fireplace flame as frequently occurs in auxiliary air installations in which air is introduced either directly beneath the fuel or immediately in front thereof and directed more or less laterally toward the front of the combustion zone where smoking, as well as unduly rapid consumption of fuel is the result. The device comprising the invention also may be employed with fireplaces having other forms of auxiliary heat forming and distribution, such as certain shell-like constructions sold commercially under the tradename "HEATALOR" and otherwise. Further, it is to be noted that no auxiliary power means are required to operate the device of the present invention, such as auxiliary blowers operated by electric motors and the like, which is common to a number of existing auxiliary air devices for fireplaces, some of which are associated with means to introduce outside air, as well as those consuming warm air from within the room in which the fireplace is installed.
The foregoing description illustrates preferred embodiments of the invention. However, concepts employed may, based upon such description, be employed in other embodiments without departing from the scope of the invention. Accordingly, the following claims are intended to protect the invention broadly, as well as in the specific forms shown herein. | An auxiliary draft device for a fireplace to produce a curtain of air discharged upwardly in front of the fireplace opening and comprising a horizontal sheet metal air-distributing shell having fixed walls and decreasing in width from one end to the other to effect a substantially even discharge of air across said fireplace opening by air discharge openings in the top wall of the shell, said shell being supported solely by a floor adjacent the hearth of the fireplace and which, at the wider end thereof, is connected to an extension shell of sheet metal which is a plenum chamber at one side of the fireplace which communicates with a horizontal conduit extending along one side of the fireplace, transversely to said chamber and extending through the exterior wall of room in which the fireplace is located and communicating with outdoor air, inlet of which is controlled by an adjustable exterior damper operable by manual adjustment of mechanism extending from said damper to the interior of said room. | 5 |
FIELD OF THE INVENTION
[0001] The present invention relates in general to the detection of Pseudomonas aeruginosa ( P. aeruginosa ) strains exhibiting multi-resistance to antibiotics. In particular, the present invention pertains to a micro-array for the detection of antibiotic resistance determinants in said organism, a method for the detection of said determinants and a kit. This micro-array concept offers the rapid, sensitive and specific identification of antibiotic resistance profiles. It is easily expandable and may thus be adapted to changed clinical and epidemiological requirements in clinical diagnosis as well as in epidemiological studies.
BACKGROUND OF THE INVENTION
[0002] P. aeruginosa is an opportunistic pathogen associated with nosocomial infections of immuno-compromised patients especially in intensive care units (ICUs). P. aeruginosa is responsible for approximately 10% of all infections on ICUs and results in a high mortality and morbidity when associated with pneumonia or septicemia (Prevention, C.f.D.C.a.; Am. J. Infect. Control. 24 (1996), 380-388). This organism is characterized by an intrinsic resistance to various antimicrobial agents and an ability to develop multiresistance during antibiotic therapy (Livermore, D. M.; Clinical Infectious Diseases 34 (2002), 634-40). The intrinsic multiresistance results from the synergy between broadly specific drug efflux pumps and a low degree of outer membrane permeability. A variety of efflux systems have been identified to date, including the well characterized MexAB-OprM, MexCD-OprJ, MexEF-OprN and MexXY-OprM efflux pumps (Masuda, N., et al.; Antimicrob. Agents Chemother. 44(12) (2000), 3322-7). MexAB-OprM is constitutively expressed in wild type P. aeruginosa PAO1, whereas the other efflux systems are not. Mutations in regulatory genes of these efflux systems (mexR, mexT, nfxB) can either cause overexpression of MexAB-OprM or may induce expression of the other regulated efflux systems. P. aeruginosa may as well harbour different plasmid encoded antibiotic resistance genes like −lactamases (tem, shv, oxa), aminoglycoside modifying enzymes (aac, aad, aph) and carbapenemases (imp, vim). These plasmids can be easily acquired via horizontal gene transfer from other gram-negative organisms, especially in a clinical setting.
[0003] So far, detection of P. aeruginosa has been performed by isolating nucleic acid sequences from clinical samples and analyzing them by either using gel electrophoresis of DNA fragments (e.g. of restriction fragments)—the so-called southern blot, hybridization events, and the direct sequencing of DNA (for example according to the Maxam-Gilbert method). All of the above-mentioned methods are widely used in biological sciences, medicine and agriculture. The deficiencies of the three methods reside, however, in that even though southern blots and hybridization experiments may be carried out relatively fast, they are only useful for the analysis of short DNA strands. The DNA sequencing results in the accurate determination of the nucleic acid sequences, but is time consuming, expensive and connected with certain efforts when applied to greater projects, e.g. the sequencing of a complete genome.
[0004] Known methods to detect the presence of P. aeruginosa in a clinical sample reside e.g. in real-time polymerase chain reactions (cf. US 2004/248148) or other PCR based assays (cf. US 2003/180733), which use primers specific for particular genes of said organism. Also, the use of enzyme linked immunosorbant assays and Western blot immunoassays for the detection of P. aeruginosa is disclosed for example in U.S. Pat. No. 6,551,795 and EP 0 265 672.
[0005] Since these phenotypic based microbiological and biochemical techniques for species identification and antibiotic susceptibility determination require at least two days, a reliable therapy is not possible in urgent cases of critical ill patients. The development of new and faster methods is therefore a crucial point to allow a better adjustment of the antibiotic treatment of severe infections caused by multiresistant pathogens.
[0006] The micro-array technology represents in contrast to e.g. PCR and antibody basing methods, a tool for a highly specific, parallel detection of thousands of different DNA sequences in a single experiment (Schena, M. et al.; Science 270 (1995), 467-470). Micro-arrays which are in some cases also referred to as hybridization arrays, gene arrays or gene chips comprise in brief a carrier or support on which at defined locations at a possibly high density capture molecules are attached directly or via a suitable spacer molecule. The spacer molecules may be considered to function as a “bridge” between the capture molecule and the surface of the carrier to allow an easier attachment of the capture molecule. Said capture molecules consist of relatively short nucleic acid sequences, in particular DNA, which is capable to hybridize specific to the target molecules or probe molecules to be analyzed resulting usually in DNA:DNA or DNA:RNA hybrids. The occurrence of the hybridization event is than detected with for example fluorescent dyes and analyzed.
[0007] The advantages of the micro-array concept resides preliminary in its ability to carry out very large numbers of hybridization-based analyses simultaneously. Originally developed for the analysis of mammalian gene expression, an increasing number of reports on micro-arrays for identification and characterization of prokaryotes also used in microbial diagnostics was encountered in recent years (Bodrossy, L. and A. Sessitsch; Curr. Opin. Microbiol. 7 (2004), 245-254). Combination of PCR based pre-amplification steps with subsequent micro-array based detection of amplicons on a micro-array facilitates the sensitive and highly specific detection of PCR products (Call, D. R. et al.; Int. J. Food Microbiol. 67 (2001), 71-80). Amplicons are identified by a specific hybridization reaction on the array thus reducing the risk of wrong positive results due to the occurrence of nonspecific bands after PCR. Besides that, micro-arrays utilizing oligonucleotides as capture probes enable the detection of single nucleotide polymorphisms (SNPs) such as resistance mutations without the need for additional sequencing. However, only a few studies describe the development of diagnostic micro-arrays for the molecular detection of bacterial antibiotic resistance, targeting either a limited number of acquired antibiotic resistance genes or resistance mutations in various genes.
[0008] The use of micro-arrays for the detection of pathogenic bacteria is for example disclosed in WO 03/031654, wherein a micro-array with probes for genotyping Mycobacteria species, differentiating Mycobacterium strains and detecting antibiotic-resistant strains is specified. The simultaneous performance on multiple clinical isolates through a single test of a Mycobacterium genotyping test, M. tuberculosis strain differentiation test and an antibiotic-resistance detection test is specified.
[0009] WO 01/7737 relates to the identification (detection and/or quantification) of (micro-) organisms among others having homologous nucleotide sequences by identification of their nucleotide sequences, after amplification by a single primer pair. Organisms of the same genus or family may and/or related genes in a specific (micro) organism present in a biological sample may be identified or quantified.
[0010] Methods for assaying drug resistance and kits for performing such assays are disclosed in the U.S. Pat. No. 6,013,435. Target sequences associated with genetic elements are selectively amplified and detected. The methods described herein are especially useful for screening of Microorganisms, which are difficult to culture.
[0011] In US 2003143591 methods and strategies to detect and/or quantify nucleic acid analytes in micro-array applications such as genotyping (SNP analysis) are disclosed. Nucleic acid probes with covalently conjugated dyes are attached either to adjacent nucleotides or at the same nucleotide of the probe while novel linker molecules attach the dyes to the probes.
[0012] The disadvantages of the techniques according to the state of the art for the detection of P. aeruginosa reside in that they require long runs and are solely adaptive to a limited number of samples to be tested and often also expensive. Additionally, no method is known which uses simultaneously several nucleic acids probe for the detection of multiple antibiotic resistance determinants and optionally other virulence factors to facilitate an overview on the resistance properties of a single strain and gives valuable and sometimes life-saving information about a suitable treatment.
SUMMARY OF THE INVENTION
[0013] The present invention provides a micro-array as a genotype based method for detecting antibiotic susceptibility of P. aeruginosa, which incorporates nucleic acids for targeting determinants of multi-resistant P. aeruginosa and optionally specific controls. The micro-array enables a rapid, accurate and inexpensive identification of antibiotic resistance profiles of P. aeruginosa. The inclusion of nucleic acids representing virulence factors, like toxins or alginate, broadens the information about the virulence potential of P. aeruginosa at the same time. Said micro-array is easily expandable and may thus be adapted to changing clinical and epidemiological requirements in clinical diagnosis as well as in epidemiological studies. A fast and reliable assay with a high throughput may be helpful in reducing the spread of multiresistant isolates and improves the treatment options of severe and often life-threatening P. aeruginosa infections.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] In FIG. 1 , an embodiment of a micro-array according to the invention is shown. All capture probes were spotted in triplicates. The mutation position is assigned for single nucleotide polymorphisms (SNPs) and the insertions and deletions of respective genes. Modifying enzyme genes are named according to their substrate specificity. Genes relevant for resistance by their presence were named with the usual name. The different genes are indicated in the array legend. For SNPs, the central base in the probe A, T, G, C is spotted in one row below the other, for insertions and deletions, a wild-type probe below a mutation probe, and for gene presence an anti-sense down to sense probe.
[0015] FIG. 2 shows a genotype analysis of respective resistance and virulence genes of the clinical P. aeruginosa isolate No. 23 (b), which was performed using the inventive micro-array and were compared with wild-type P. aeruginosa PAO1 (a). The signal intensity is shown in false color, in intensity increasing from grey to white. The frames highlight the positions in which the two isolates differ from each other.
[0016] In FIG. 3 , the percent of mismatch probes depending on the mismatch positions (MM)/perfect match position (PM) ratio from all hybridization experiments of the P. aeruginosa test collective is shown.
[0017] FIG. 4 shows a genotype analysis by the present micro-array of 3 consecutive P. aeruginosa isolates collected from the same patient Array detail of the 3 isolates (No. 1=a, No. 2=b, No. 3=c) covering gyrA and parC and aminoglycoside modifying enzymes is shown. The signal intensity is shown in false color, in increasing intensity from grey to white.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Definitions
[0018] The term “micro-array” as used herein refers to a carrier or support respectively, which is preferably solid and has a plurality of molecules bound to its surface at defined locations or localized areas. The molecules bound to the carrier comprise nucleic acid sequences, the capture molecules, which are specific for a given or desired target sequence. The sequences may be bound to the carrier via spacer molecules, which bind each capture nucleotide to the surface of the support. In the above context a localized area is an area of the carrier's surface, which contains capture molecules, preferably attached by means of spacers to the surface of the carrier, and which capture molecules are specific for a determined target/probe molecule.
[0019] “Spacers” are molecules that are characterized in that they have a first end attached to the biological material and a second end attached to the solid carrier. Thus, the spacer molecule separates the solid carrier and the biological material, but is attached to both. The spacers may be synthesized directly on or may be attached as a whole to the solid carrier at the specific locations, whereby masks may be used at each step of the process. The synthesis comprises the addition of a new nucleotide on an elongating nucleic acid in order to obtain a desired sequence at a desired location by for example photolithographic technologies which are well known to the skilled person. Bindings within the spacer may include carbon-carbon single bonds, carbon-carbon double bonds, carbon-nitrogen single bonds, or carbon-oxygen single bonds. The spacer may be also designed to minimize template independent noise, which is the result of signal detection independent (in the absence) of the template. In addition, the spacer may have side chains or other substitutions. The active group may be reacted by suitable means to form for example preferably a covalent bound between the spacer and solid carrier, capture or probe molecule. Suitable means comprise for example light. The reactive group may be optionally masked/protected initially by protecting groups. Among a wide variety of protecting groups, which are useful are for example FMOC, BOC, t-butyl esters, t-butyl ethers. The reactive group is used to build to attach specifically thereto (after the cleavage of the protecting group) another molecule.
[0020] The “localized area” is either known/defined by the construction of the micro-array or is defined during or after the detection and results in a specific pattern. A spot is the area where specific target molecules are fixed on their capture molecules and approved by a detector.
[0021] As used herein, the term “carrier” or “support” refers to any material that provides a solid or semi-solid structure and a surface allowing attachment of molecules. Such materials are preferably solid and include for example metal, glass, plastic, silicon, and ceramics as well as textured and porous materials. They may also include soft materials for example gels, rubbers, polymers, and other non-rigid materials. Preferred solid carriers are nylon membranes, epoxy-glass and borofluorate-glass. Solid carriers need not be flat and may include any type of shape including spherical shapes (e.g., beads or microspheres). Preferably solid carriers have a flat surface as for example in slides (such as object slides) and micro-titer plates, wherein a micro-titre plate is a dished container having at least two wells.
[0022] The expression “attached” describes a non-random chemical or physical interaction by which a connection between two molecules is obtained. The attachment may be obtained by means of a covalent bond. However, the attachments need not be covalent or permanent. Other kinds of attachment include for example the formation of metalorganic and ionic bonds, binding based on van der Waal's forces, or any kind of enzyme substrate interactions or the so called affinity binding. An attachment to the surface of a carrier or carrier may be also referred to as immobilization.
[0023] A “determinant” relates to a factor responsible for the development of resistance in P. aeruginosa, which may be acquired by the micro-organism via horizontal gene transfer and which actively counteracts the effect of an antibiotic. Particularly, the genes conveying resistance to antibiotics, such as mexR, mexT, nfxB, mucA, parC, gyrA, exoU, exoS, exoT, pse, oxa, imp, vim, aac, aph and aad, which may be normally present on plasmid(s) or also may be incorporated in the genome of P. aeruginosa, are envisaged. Also virulent factors, such as e.g. genes involved in the synthesis of toxins and alginate are comprised by said term.
[0024] The terms “complementary” or “complementarity” are used in reference to polynucleotides (i.e., a sequence of nucleotides such as an oligonucleotide or a target nucleic acid) in the light of the base-pairing rules. Complementarity may be partial, in which only some bases of the nucleic acids are matched according to the base pairing rules. Alternatively, there may be a complete complementarity between the nucleic acids in such a way that there are no mismatches. The degree of complementarity between nucleic acid strands has significant effects on the stringency and strength of the hybridization between two different nucleic acid strands. Complementarity as used herein is not limited to the predominant natural base pairs. Rather, the term also encompasses alternative, modified and non-natural bases, including but not limited to those that pair with modified or alternative patterns of hydrogen. With regard to complementarity, it is important for some applications to determine whether the hybridization represents a complete or partial complementarity. If it is desired for example to detect the presence or absence of a particular DNA (such as from a virus, bacterium, fungi or protozoan), the only important condition is that the hybridization method ensures hybridization when the relevant sequence is present. Other applications in contrast, may require that the hybridization method distinguish between partial and complete complementarity, for example in the detection of genetic polymorphisms.
[0025] The term “homology” and “homologous” refers to a degree of identity. There may be partial homology or complete homology. A partially homologous sequence is one that is less than 100% identical to another sequence.
[0026] “Hybridization” is used in reference to the pairing of complementary nucleic acids. Hybridization and the strength of hybridization (i.e., the strength of the association between the nucleic acids) is influenced by such factors as the degree of complementarity between the nucleic acids, stringency of the conditions involved, and the melting temperature of the formed hybrid. Hybridization involves the annealing of one nucleic acid to another complementary nucleic acid, i.e., a nucleic acid having a complementary nucleotide sequence.
[0027] “Stringency” refers to the conditions, which are involved in a correct hybridization event, for example temperature, ionic strength, pH and the presence of other compounds, under which nucleic acid hybridizations are conducted. Under conditions of high stringency, nucleic acid base pairing will occur only between nucleic acid fragments that have a high frequency of complementary base sequences. Thus, conditions of weak or low stringency are often required when it is desired that nucleic acids that are not completely complementary to one another be hybridized or annealed together.
[0028] A “marker” or “label” refers to any atom or molecule that may be used to provide a detectable (preferably quantifiable) effect and that can be attached to a nucleic acid. Markers may include colored dyes; radioactive labels; binding moieties such as biotin; haptens such as digoxigenin; luminogenic, phosphorescent or fluorogenic moieties; and fluorescent dyes alone or in combination with moieties that can suppress or shift emission spectra by the energy transfer of fluorescence. Markers may provide signals, which are detectable for example by fluorescence, radioactivity, colorimetry, gravimetry, X-ray diffraction or absorption, magnetism and enzymatic activity. A marker may be a charged moiety (positive or negative charge) or may also have a neutral charge. They may include or consist of nucleic acid or protein sequence. Preferred markers are fluorescent dyes.
[0029] A “target” or “probe molecule” refers to a nucleic acid molecule to be detected. Target nucleic acids may contain a sequence that has at least a partial complementarity with at least a probe oligonucleotide.
[0030] “Probes” or “probe molecules” refer to nucleic acids, which interact with/hybridize to a target nucleic acid to form a detection complex.
[0031] The term “signal probe” or “probe” relates to a probe molecule, which contains a detectable moiety, which are already outlined above.
[0032] The term “nucleic acid” is meant to comprise any sequence of deoxyribonucleotides, ribonucleotides, peptido-nucleotides, including natural and/or artificial nucleotides.
[0033] The expression “sample” is meant to include any specimen or culture of biological and environmental samples or nucleic acid isolated therefrom. Biological samples may be animal, including human, fluid, such as blood or urine, solid or tissue, alternatively food and feed products and ingredients such as dairy items, vegetables, meat and meat by-products. Environmental samples include environmental material such as surface matter, soil, water, industrial samples and waste, for example samples obtained from sewage plant, as well as samples obtained from food and dairy processing instruments, apparatus, equipment, utensils, disposable and non-disposable items. The sample may be used as such in the assay or may be subjected to a preliminary selection step, such as e.g. culturing the sample under conditions favoring or selecting for P. aeruginosa in said sample. Also, the nucleic acids contained in the sample may be isolated prior to performing the assay. In the presence of a multi-resistant P. aeruginosa in the sample the resulting nucleic acid sample will contain the target nucleic acid which may be isolated from the biological sample in any way known to the skilled person, including conventional isolation comprising lysis of the cellular material of the biological sample and isolation of DNA or RNA therefrom. In case the target nucleic acid is present in a low amount, the said nucleic acid may be subjected to PCR, preferably to a multiplex PCR, to specifically amplify the target nucleic acid prior to performing the assay.
[0034] A “nucleic acid sample” may be a polynucleotide or oligonucleotide of a variable length and is represented by a molecule comprising at least 5 or more deoxyribonucleotides, preferably about 10 to 1000 nucleotides, more preferably about 20 to 800 nucleotides and more preferably about 20 to 100 or even more preferred about 20 to 60. The exact size will depend on many factors, which in turn depend on the ultimate function or use of the oligonucleotide.
[0035] As used herein, the term “kit” refers to any delivery system for delivering materials. In the context of reaction assays, such delivery systems include systems that allow for the storage, transport, or delivery of reaction reagents (e.g., oligonucleotides, enzymes, etc. in the appropriate containers) and/or supporting materials (e.g., buffers, written instructions for performing the assay etc.) from one location to another.
[0036] As used herein, the term “kit” refers to any delivery system for delivering materials. In the context of reaction assays, such delivery systems include systems that allow for the storage, transport, or delivery of reaction reagents (e.g., oligonucleotides, enzymes, etc. in the appropriate containers) and/or supporting materials (e.g., buffers, written instructions for performing the assay etc.) from one location to another.
[0037] According to an embodiment, the present micro-array comprises a carrier or support on which in the form of a specific pattern nucleic acids are immobilized. Said nucleic acids comprise sequences specific for at least 8 determinants of P. aeruginosa. For a correct determination of the presence of multi-resistant P. aeruginosa in a sample a number of at least eight determinants have proven to yield a doubtless, non-ambiguous result. Since due to single nucleotide polymorphisms (SNPs) contained in a particular determinant, said determinant has to be characterized by more than one nucleic acid sequence, so that more than one capture probe is required for particular determinants to provide a detectable hybridisation event under stringent conditions. In consequence, also number of nucleic acid capture probes corresponding to known SNPs is attached to the surface of the carrier of the present micro-array to act as the capture molecule for the particular determinant, thereby allowing the individual and unambiguous detection of each SNP of said determinant. The different capture probes (for the different SNPs) for one particular determinant may be attached to the carrier (e.g. spotted) on one localized area or on different ones.
[0038] Said immobilized nucleic acids comprise sequences specific for at least 8 determinants of P. aeruginosa, which sequences are preferably randomly selected from the group consisting of mexR, mexT, nfxB, mucA, parC, gyrA, exoU, exoS, exoT, pse, oxa, imp, vim, aac, aph and aad. Each of these determinants is detected either by a single capture probe or a set of two or more capture probes, which number of capture probes depend from the number of SNPs said determinant embraces. For a correct and unambiguous identification of the strain and the detection of a multiresistant P. aeruginosa strain 8 determinants, which may include resistance genes and other genes conferring virulence to said strain, have proven to be sufficient without any requirements concerning the selection of the determinants. The detection of 9 or more determinants is preferred, since in this case more precise information about antibiotic determinants and other virulence factors are achieved. Thus, the present micro-array may also comprise nucleic acids probes specific for at least 9 to 11 determinants, more preferably at least 12 to 14 determinants, still more preferably at least 15 determinants and most preferably nucleic acids probes specific for 16 determinants.
[0039] The inclusion of P. aeruginosa specific control capture probes (oprI and gyrB) as well as capture probes for the detection of a broad range of gram-negative organisms (srv3) allows a more correct species identification.
[0040] The carrier or support of the present DNA micro-array may consist of different materials, preferably of glass, silicon, silica, metal, plastics or mixtures thereof prepared in format selected from the group of slides, discs, gel layers and/or beads. The carrier may also be a microplate or a slide and may consist of epoxy glass. A preferred support is for example an epoxy modified glass slide purchased by Elipsa AG, Berlin, Germany.
[0041] Preferably, the present micro-array has at least 100 molecules attached per square centimeter of the solid carrier. This density may be, however, higher and be adapted to the respective application of the micro-array, in that also other suitable applications may be performed, e.g. for the determination of resistances in other organisms different from P. aeruginosa and/or for the detection of resistance gene(s), which are unknown yet to play a role in P. aeruginosa. For example, the density of the nucleic acids probes attached per square centimeter of solid carrier amounts more preferably at least to 1.000, still more preferably at least to 5.000 and most preferably at least to 10.000 nucleotides per square centimeter.
[0042] Said specific pattern allows the mapping of each nucleic acid probe to a specific position on said carrier and a specific analysis, in that the analysis of the results of the present micro-array is facilitated and non-ambiguous concerning the attribution of a particular spot to a previous attached nucleic acid probe.
[0043] Spacer molecules of any length may be arranged between the carrier and the nucleic acids applied on the carrier. The spacer may be for example polymer-based spacers, but may also consist of an alkane chain, or any derivatives thereof, of a suitable length, which comprises at each end respective functional groups for attachment to the solid support and the nucleic acid probe. Preferably, 15-thymidine spacers have been attached with one end to the surface of the support and with the other end to the 3′-terminal end of the respective nucleic acid to be immobilized.
[0044] According to another preferred embodiment, the present invention provides a method for the detection of multi-resistant P. aeruginosa strains in a sample material, using a micro-array for the detection of determinants like resistance genes and other genes conferring virulence.
[0045] The method comprises the step to obtain a sample material of interest. Prior to performing the method of the present invention the sample may be pre-treated e.g. centrifuging or filtering to separate non-soluble matter or selecting for P. aeruginosa in the sample. This may be achieved by e.g. culturing the sample under conditions favouring the growth of P. aeruginosa. Also, to improve performance, nucleic acids contained in the sample material may be isolated and/or amplified. The sample and/or the isolated/purified nucleic acid material is applied to the surface of the present micro-array. Said sample is now allowed to hybridize to the immobilized nucleic acids, the capture probes, for targeting at least 8 determinants of P. aeruginosa. By choosing suitable hybridisation conditions known to the skilled person, such as e.g. applying a certain stringency during hybridization and washing (cf. Maniatis et al., Molecular Cloning—A Laboratory Manual, First Edition, Cold Spring Harbor, 1982), only those nucleic acids will hybridize to the immobilized nucleic acids and/or remain bound during washing steps, which exhibit a high homology to the immobilized nucleic acids. The method further comprises detecting any hybridisation event, which will be indicative of the presence of a multi-resistant P. aeruginosa.
[0046] Said nucleic acids probes specific for targeting at least 8 determinants of P. aeruginosa are preferably randomly selected from the group consisting of mexR, mexT, nfxB, mucA, parC, gyrA, exoU, exoS, exoT, pse, oxa, imp, vim, aac, aph and aad. Each of these determinants is detected by a specific set of capture probes, which may comprise more than one nucleic acid probe in accordance to the number of SNPs said determinant embraces. For a correct and non-ambiguous indentification of the strain and the determination of a multiresistant P. aeruginosa strain 8 determinants, which include resistance genes and other genes conferring virulence to said strain, have proven to be sufficient without any requirements concerning the selection of the determinants. Preferably, the micro-array may also comprise nucleic acids specific for at least 9 to 11 determinants, more preferably at least 12 to 14 determinants, still more preferably at least 15 determinants and most preferably 16 determinants.
[0047] P. aeruginosa specific control probes (oprI and gyrB) may be included. Other controls are probes, which are capable to detect a broad range of gram-negative organisms (srv3) for a correct species identification.
[0048] The nucleic acid sample to be used for hybridizing to the immobilized nucleic acids consists preferably of oligonucleotides and/or polynucleotides of a length between 10 and 1000 nucleotides each, preferably shorter oligonucleotides/polynucleotides exhibiting a length of about 10 to 100 or between 20 to 60. The length may be obtained for example by the digestion of plasmid or genomic DNA with DNAse or preferably restrictions enzymes and facilitates the hybridization.
[0049] The nucleic acid sample, which comprises oligonucleotides and/or polynucleotides, is preferably isolated from body tissues or fluids, particularly blood, suspected to contain P. aeruginosa, followed by the isolation and optional the amplification of the DNA and/or RNA contained therein by PCR techniques, such as a multiplex PCR, which allows the amplification of several DNA fragments in one PCR reaction. Such techniques are well known to the skilled person and may be also performed with commercial available kits.
[0050] The capture and the target nucleic acids may be present in a labeled form. The target nucleic acids may be labeled prior to performing the assay, by including a marker molecule into the molecule, e.g. during its amplification or isolation. Said marker molecule is preferably a fluorescent marker. Also the capture molecules may be labeled, in case of a fluorescent dye preferably with a dye exhibiting a different excitation and/or emittance wavelength, which allows a normalization of the experiment.
[0051] Methods for the detection of binding include e.g. surface plasmon resonance or detection of fluorescence at a localized area indicative of binding of a labelled molecule. Fluorescence may be detected e.g. via confocal laser induced fluorescence.
[0052] In another embodiment of the invention, a diagnostic kit is provided for the detection of P. aeruginosa infections.
[0053] Said kits either provides the nucleic acids specific for 16 determinants of P. aeruginosa, which determinants are selected from the group consisting of mexR, mexT, nfxB, mucA, parC, gyrA, exoU, exoS, exoT, pse, oxa, imp, vim, aac, aph and aad. Alternatively, the kit may also provide a micro-array as detailed above.
[0054] Additionally, the kit may also include the appropriate controls, in that probes are included specific for the gyrB, oprI and srv3 genes.
[0055] A typical automated processing of a micro-array according to a preferred embodiment of the present invention includes the use of three components. First, the micro-array or support respectively, second a reader unit and third means for the evaluation of the results, e.g. a suitable computer software. The reader unit comprises in general a movable tray, focusing lens(es), mirrors and a suitable detector, e.g. a CCD camera. The moveable tray carries the micro-array and may be moved to place the micro-array within the light path of one or more suitable light sources, e.g. a laser with an appropriate wavelength to excite a fluorescent compound. The evaluation program or software may serve for example to recognize specific patterns on the array or to analyze different expression profiles of genes. In this case, the software searches colored points on the array and compares the intensity of different color spectra of the same point. The result may be interpreted by an analyzing unit and afterwards stored in a suitable file format for further processing.
[0056] As detailed above, the probe- and/or target-nucleic acids may be labelled each with a fluorescent dye and the intensity of the fluorescence at different wavelengths of each point is compared to the background. The detector, e.g. a photomultiplier or CCD array, transforms low light intensities to an amplifiable electrical signal. Other methods use different enzymes, which are covalently bound to the nucleotide by means of a linker molecule. The enzymatic colorimetry uses for example alkaline phosphatase and horseradish peroxidase as marker. By contacting with a suitable molecule, a detectable dye may be achieved. Other chemoluminescent or fluorescent marker comprise proteins capable to emit a chemoluminescent or fluorescent signal, if irradiated with light of a discrete, specific wavelength, e.g. 488 nm for the green fluorescent protein. Radioactive markers are applied in case of low detection limits are required, but are due to their harmful properties not wide spread. Fluorescence marking is performed with nucleotides linked to a fluorescent chromophore. Combinations of nucleotides and fluorescent chromophore comprise in general Cy3 (cyanine 3)/Cy5 (cyanine 5) labelled dUTP as dye, since they may be easily incorporated, the electron migration for fluorescence may be exited by means of customary lasers and they also have distinct emission spectra.
[0057] The hybridisation of micro-arrays follows essentially the conventional conditions of southern or northern hybridisations, which are well known to the skilled person. The steps comprise a pre-hybridisation, the intrinsic hybridisation and a washing step after hybridisation occurred. The conditions have to be chosen in such a way that background signals are kept low, minimal cross-hybridisation (in general a reduced number of mismatches) occurs and with a sufficient signal strength, which has to be proportional for some applications to the concentration of the target molecule.
[0058] The hybridisation event may be detected generally by two different kinds of array-scanners. One method employs the principle of the confocal laser microscopy, which uses at least one laser to scan the array in point-to-point manner. Fluorescence is than detected by photomultipliers, which amplify the emitted light. The cheaper GGD basing readers use typically filtered white light for the excitation. The surface of the array is scanned with this method in sections, which allows the faster achievement of results of a lower significance.
[0059] Also the so-called gridding for the analysis of the results, in which an idealised model of the layout of the micro-array is compared with the scanned data to facilitate the spot definition. Pixels are classified (segmented) as spot (foreground) or background to produce the spotting mask. Segmentation techniques may be divided in fixed segmentation circle, adaptive circle segmentation, adaptive shape segmentation and histogram segmentation. The use of these techniques depends from the shape of the spots (regular, irregular) and the quality of the proximal arrangement of the spots.
[0060] Another issue is the intensity of the distinct spots, since the concentration of hybridised nucleotides in one spot is proportional to the total fluorescence of this spot. In particular, the overall pixel intensity and the ratio of the different fluorescent chromophores used (in case of Cy3 and Cy5, green and red) are important for the calculation of the spot intensity. Beneath the spot intensity, also the background intensity has to be taken into account, since various effects may disturb the fluorescence of the spots, for example the fluorescence of the support and of the chemicals used for the hybridisation. This may be performed by the so-called normalisation, which includes the above-mentioned effects and others like fluctuations of the light source, the lower availability/incorporation of the distinct marker molecules (Cy5 worse than Cy3) and their differences in emission intensities. Of importance for the normalisation is further the reference against which shall be normalized. In general, this may be a specific set of genes or a group of control molecules present on the micro-array.
[0061] The results may be further processed by means of the available software tools and according to the knowledge of bioinformatics.
[0062] The present invention provides a method, a micro-array and kit for the detection of P. aeruginosa infections, helpful in reducing the spread of multi-resistant isolates and improve the treatment options of severe and often life-threatening P. aeruginosa infections. The present inventors could verify surprisingly in the course of their studies also the presence of a vim gene in a clinical isolate, which represents the first alarming occurrence of said determinant in connection with a multi-resistant P. aeruginosa strain in Germany.
[0063] It is to be understood, that the above description is intended to be illustrative and not restrictive. Many embodiments will be apparent to those of skilled in the art upon reviewing the above description. By way of example, the invention has been described preliminary with reference to the use of nucleic acids comprising sequences specific for the resistance and virulence determinants of P. aeruginosa. It should be clear that also other resistance and virulence determinants may be selected in dependence from the genetic development of multiresistant P. aeruginosa strains. The scope of the invention should, therefore, be determined not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.
EXAMPLES
A. Bacterial Strains and Culture Conditions
[0064] The wild-type reference strain P. aeruginosa PAO1 was obtained from the ATCC (AT47085). The other P. aeruginosa strains were collected from patients at the Robert Bosch Hospital in Stuttgart, Germany. They were recovered from respiratory samples (n=51), swabs (n=5), urine (n=2) and faeces (n=2). All isolates were identified with the API 20NE system (bioMerieux, Marcy l'Etoile, France) and the NEG Breakpoint Combo Type 30 panel on the MicroScan WalkAway®-96 SI system (Dade Behring, Liederbach, Germany). All bacterial strains were either routinely cultured at 37° C. on Mueller-Hinton (MH) agar or grown in Luria Bertani broth (LB).
B. Antibiotic Susceptibility Testing
[0065] The antibiotic susceptibility was determined with the NEG MIC Type 30 panel on the MicroScan WalkAway®-96 SI system. The MICs were interpreted according to the NCCLS guidelines. The strains were tested for aztreonam (AZT), ceftazidime (CAZ), cefepime (CPE), piperacillin (PI), piperacillin/tazobactam (P/T), imipenem (IMP), meropenem (MER), levofloxacin (LVX), ciprofloxacin (CP), colistin (COL), gentamicin (GM), tobramycin (TO) and amikacin (AK).
C. DNA Methods, PCR, Labeling and Sequencing
[0066] Chromosomal DNA was extracted with the QIAmp DNA Mini Kit, plasmid DNA with the QIAprep Spin Miniprep Kit according to manufacturer's instructions (Qiagen, Hilden, Germany). A set of 4 multiplex PCRs (Tab. 1) was set up to amplify the sequences of interest from the chosen genes. The PCRs were carried out with the Advantage®-GC Genomic PCR Kit (BD Bioscience, San Jose, USA) according to manufacturer's instructions, for fluorescence labeling 5 μl of each 1 mM dNTP was used, for dCTP a 2:3 mixture of Cy3-dCTP and dCTP. The cycle reactions consisted of 30 cycles of 30 s at 95° C., 30 s at 55° C. and 1 min at 72° C. PCR products were purified with the QIAquick PCR Purification Kit (Qiagen, Hilden, Germany) according to the manufacturer's instructions. The quality and sizes of PCR products were checked on a lab-on-a-chip Bioanalyzer 2100 electrophoresis with the DNA 1500 LabChip kit (Agilent, Böblingen, Germany). Sequencing was performed on the ABI PRISM® 310 Genetic Analyzer using the BigDye® Terminator Cycle Sequencing Kit v 1.1 (Applied Biosystems, Foster City, USA). The manufacturer's protocol was followed using the same primers as for the multiplex PCRs. Sequences were assembled, aligned and analyzed with the Lasergene software, Version 5.08 (DNAStar, Madison, USA).
D. Probe Design
[0067] Oligonucleotide probes specific for positions affected by SNPs were designed to have a nucleotide responsible for perfect match/mismatch at a central position. A set of 4 oligonucleotide probes was designed for each particular SNP having identical sequence except that for the central base, which was one of the 4 possible nucleotides A, T, G or C. A reliable detection of mutations due to insertion or deletion of particular bases was achieved with two probes optimized either for wild-type sequence or mutated sequence. The presence of relevant genes was confirmed with a set of two probes for each gene. Both probes were designed to represent the same sequence, one for sense direction and the other one for anti-sense direction. In order to keep all the probes within a certain thermal range for a simultaneously hybridization, the length of the capture oligonucleotides were varied between 17 and 24 bases.
E. Array Fabrication
[0068] The oligonucleotide array consisted of 202 amino-modified capture probes containing a poly-(T) 15 spacer at the 5′-end. They were synthesized by MWG Biotech (Ebersberg, Germany) and resuspended in spotting buffer S1 (160 mM Na 2 SO 4 , 130 mM Na 2 HPO 4 ) to a final concentration of 20 μM. The array layout is shown in FIG. 1 . Each capture probe was spotted in triplicates on CreativeChip™ Oligonucleotide slides (Elipsa AG, Berlin, Germany) with the Microgrid II arraying system using MicroSpot 2500 pins (Biorobotics, Cambridge, UK). Spotted capture probes were covalently immobilized to the glass surface by incubation at 60° C. for 30 min in a drying compartment (Memmert, Schwabach, Germany). Blocking and cleaning of the fabricated slides until further use was performed according to the manufacturer's instructions.
F. Controls.
[0069] Several controls were included on the array:
[0070] a spotting control (5′-cyanine 5 [Cy3]-TTTTTTTTTTTTTTCTAGACAGCCACTCATA-3′) (SEQ ID NO: 1);
[0071] a positive hybridization control (5′-TTTTTTTTTTTTTGATTGGACGAGTCAGGAGC-3′) (SEQ ID NO: 2) complementary to a labeled oligonucleotide target (5′-Cy3-GCTCCTGACTCGTCCAATC-3′) (SEQ ID NO: 3), which was spiked during hybridization; and
[0072] a negative hybridization control (5′-TTTTTTTTTTTTTTCTAGACAGCCACTCATA-3′) (SEQ ID NO: 4). All these control sequences are unrelated to sequences found in bacterial species.
G. Fragmentation
[0073] In order to increase hybridization efficiency, the amplified and labelled target DNA was diluted to a concentration of 30 ng/μl in reaction buffer (40 mM Tris/HCl, pH 8.0, 10 mM MgSO 4 , 1 mM CaCl 2 ) and fragmented with DNAseI (11.5 mU/μl) (Invitrogen, Karlsruhe, Germany) at room temperature for 5 min. The reaction was stopped by addition of 3 mM EGTA and incubation at 65° C. for 10 min.
H. Hybridization
[0074] 400 ng fragmented target DNA with addition of control DNA (0.05 pmol) were hybridized under a 18 mm×18 mm cover glass in 30 μl of 6×SSPE (1× is 0.18 M NaCl, 10 mM NaH 2 PO 4 , and 1 mM EDTA [ph 7.7]), incubated in an Eppendorf Thermomixer Comfort (Eppendorf AG, Hamburg, Germany) at 55° C. for 1 h. After hybridization the slides were washed with 2×SSC, 0.1% SDS then 2×SSC (1× is 0.15 M NaCl plus 0.015 M sodium citrate) and 0.2×SSC, each time for 10 min at room temperature with agitation in a glass container. Finally, the slides were dried with air.
I. Data Acquisition and Processing
[0075] The oligonucleotide arrays were scanned with an arrayWoRx Biochip Reader (Applied Precision, Marlborough, UK). The scanner settings for fluorescence signal acquisition were set to “High Precision” and 0.2 s acquisition time. The image processing and calculation of signal intensity was performed with the ArrayPro software (MediaCybernetics, San Diego, USA). The net signals were obtained by subtraction of the local background from the absolute density signal. The global background area is defined as the area between the spots of the array. The software calculates a minimum, maximum and average background value from the global background data.
J. Susceptibility Profile of the Isolates
[0076] The test collective of P. aeruginosa isolates was recovered from three intensive care units (ICU) or other hospital wards as far as an unusual multidrug resistance was observed. Most isolates were obtained from respiratory samples, followed by wound swabs and urine (Tab. 3). An overview of the antibiotic susceptibilities of the isolates is shown in Tab. 4. Susceptibility profiles of the tested strains showed a typical distribution for an ICU. Ten P. aeruginosa isolates showed a concomitant antibiotic resistance against one or more antibiotics from the group of aminoglycosides, fluoroquinolones, cephalosporines and carbapenemes. Among the tested substances colistin was most effective substance with a resistance rate of 0% and imipenem the endmost effective with a susceptibility rate less than 55%.
K. Array Set-Up
[0077] The two major features of array based test systems are sensitivity and specificity. In contrast to usually methods used to discriminate specific from unspecific signals based on an internal DNA standard we defined a cut-off value based on the background fluorescence intensity. The cut-off value for a specific, positive fluorescence signal was set to 1.5 times of the minimal background signal value. Each signal, regardless perfect match or mismatch was considered as positive, if the absolute fluorescence intensity exceeded this value. Everything below was considered as unspecific and was not considered in any subsequent analyzes. FIG. 2 shows a typical array experiment with hybridization patterns of the reference strain PAO1 (a) and P. aeruginosa isolate No. 23 (b). The hybridization of an array with target DNA obtained from PAO1 revealed a minimal background fluorescence intensity of 4.86×10 9 RFU (relative fluorescence unit). The signal cut-off was set to 7.29×10 9 RFUs. For P. aeruginosa isolate No. 23 the respective values were 5.06×10 8 RFU and 7.59×10 8 RFU.
[0078] The second major feature of an array is specificity defined by the ability to discriminate between mismatch and perfect match signal. The highest fluorescence signal of each SNP or insertion/deletion position was considered as potential perfect match position (PM). The other signals of probes specific for particular mutation position were considered as potential mismatch positions (MM) and normalized to the PM value. The potential perfect match signal was set to the value of 1.0 and the mismatch signals were adjusted accordingly. The ratio of MM/PM ranged from 0.0 to 1.0. The relative intensity value of particular probe was considered as specific, if MM/PM ratio for that probe did not exceed the value of 0.7. The MM/PM ratio for all of tested capture probes remained under 0.7.
[0079] Every gene which is subject to mutations was sequenced for both strands in order to determine the correlation between array deduced genotype and sequencing based genotype. In all cases, the highest array signals for the different SNP, insertion or deletion positions corresponded to the perfect match position according to the underlying genotype determined by sequence analysis. Also the presence of plasmid or integron encoded resistance genes not subject to mutations could be verified via PCR and sequencing analysis.
L. Genotype Analysis By Array
[0080] The differential comparison of the two hybridization patterns showed a discrepant perfect match signal for positions 327, 377 and 384 in the mexR gene, position 248 in the gyrA and 240 in the parC gene ( FIG. 3 ). All differences in perfect match signal were a matter of single nucleotide polymorphism. The mutations in mexR at position G327A and G384A were silent and did not cause an amino acid exchange, but mutation T377A causing a Val126Glu exchange was responsible for respective antibiotic resistance. The mutation C248T (Ser83Leu) in the gyrase gene gyrA as well as mutation C240T (Ser80Leu) found in the topoisomerase IV gene parC leads to respective amino acid substitution that is responsible for fluoroquinolone resistance. In addition, specific fluorescence signals from isolate No. 23 indicated the presence of a vim, aac(6′)-Ib and aadA1 gene. There were no additional differences as analyzed by the presented array in genotypical characteristics of clinical isolate No. 23 and reference P. aeruginosa strain PAO1. For oprI, srv3, exoS, exoT, aadA1 and aac(6′)-Ib the signals for sense and anti-sense probes are displayed, showing that usually one get signals above the cut-off for both probes.
[0081] The 60 P. aeruginosa isolates were tested with the array applying the same hybridization conditions. Tab. 4 and Tab. 5 show a summary of the array analysis, covering the genes which are affected by mutations or are acquired by plasmid acquisition. The presence of such genes may contribute to antibiotic resistance or virulence.
[0082] The distribution of the mutations indicate the existence of hot spots at sequence positions 327, 377 and 384 for the mexR gene, 305 for the nfxB gene, 197 and 212 for mexT and 248 for the gyrA gene, respectively. 22 isolates harbored 3 mutations in mexR at position 327, 377, 384. Furthermore, the array analysis of 60 P. aeruginosa clinical isolates revealed as well the presence of plasmids or integrons encoding for antibiotic resistance genes (imp, vim, oxa, aad, aac). Concerning the group of aminoglycoside modifying enzymes, the following genes were detected: aac(6′)-Ib, aac(3)-Ia, -Ib and -II, aadA1, -2, aadB and aph(3′). In the group of β-lactamases, 8 imp and one vim-1 gene could be determined. However, the most frequent β-lactamase genes found in 17 isolates of the collective belong to the oxa-family, 13 of them the ESBL oxa-14 gene. The array data revealed the presence of virulence factors, exoS and exoT genes were found in 47 isolates, 13 isolates harbored an exoU gene. This is consistent with the usual frequencies reported for these genes. ExoS and exoT were reported to occur with a frequency of about 68%, exoU with 28%, respectively (78% and 22% respectively in our collective).
M. Interarray Variability
[0083] In order to determine if the ratio of perfect match to mismatch signal intensity after hybridization with target DNA from a set of different amplification/labeling reactions is reproducible, the array was hybridized four times with DNA obtained from PAO1. However, due to different dye incorporation and fragmentation efficiency the net intensities varied for some positions for a factor higher than three. Therefore, the relative intensity was calculated. After normalization, the overall interarray variability was 8.7%. In any case, the relation between the 4 probes specific for a single SNP position was not changed from an array to another.
O. Array Signal—Genotype Correlation
[0084] Every gene, which is subjected to mutations was sequenced for both strands in order to determine the correlation between array deduced genotype and sequencing based genotype. In all cases, the highest array signals for the different SNP, insertion or deletion positions corresponded to the perfect match position according to the underlying genotype determined by sequence analysis. Also the presence of plasmid or integron encoded resistance genes not subject to mutations could be verified via PCR and sequencing analysis.
P. Correlation of Array Based Genotype and Phenotype
[0085] The FIG. 4 shows a detail of the array analyses of three P. aeruginosa isolates that were collected from the same patient within a time period of three weeks. The first isolate was phenotypically susceptible to ciprofloxacin and tobramycin. The subsequent isolate, collected one week after the first isolate, was phenotypically already resistant against ciprofloxacin but still susceptible for tobramycin. Finally, the last of the three isolates then showed phenotypical resistance for ciprofloxacin and tobramycin. A retrospective array analysis of these three isolates correlated well with the resistance phenotype. However, due to higher sensitivity it was possible to detect resistance relevant genes and mutations even in the first isolate ( FIG. 4 ). All isolates carried a mutation at position 248 in gyrA (levofloxacin and ciprofloxacin resistance) and harbored an aac(6′)-Ib (tobramycin and amikacin resistance) and aadA1 gene (gentamicin and tobramycin resistance).
[0086] In order to compare genotype and phenotype based resistance profiles, we calculated a cumulative resistance rate against different groups of antibiotics based on the array data (Tab. 6). Since one isolate may harbor one or more mutations or resistance genes which may confer resistance to a certain antibiotic at the same time, the cumulative resistance rates predicted from our array data were 5 to 10% higher as compared with the phenotypic determined susceptibility rates.
TABLE 1 Primers used for amplification GenBank Multi- Covered Product accession plex Name genes Primer Sequence (5′-3′) Size number PCR MexR mexR MexR for GATGCCCGCGCTGATGG (SEQ ID NO: 5) 390 AE004479 I MexR rev AGGCACTGGTCGAGGAGATG (SEQ ID NO: 6) MexT mexT MexT for ATGCCTGTCAGTGATCCTATGC (SEQ ID NO: 7) 935 AE004676 MexT rev CGGGTCTCGAACGGTGGGTCCTC (SEQ ID NO: 8) NfxB nfxB NfXB for GCGACGCTGAAGGAACTGG (SEQ ID NO: 9) 240 AE004874 NfXB rev CCGGGCGGTACTGGAATA (SEQ ID NO: 10) MucA mucA MucA for CAGCTTGCGGCGAGGATGC (SEQ ID NO: 11) 454 AE004511 MucA rev GTACCACTGACGGCGGATTGTTGC (SEQ ID NO: 12) parC parC parC for CTGGATGCCGATTCCAAGCAC (SEQ ID NO: 13) 186 AB003428 parC rev GAAGGACTTGGGATCGTCCGG (SEQ ID NO: 14) gyrA gyrA gyrA for GACGGCCTGAAGCCGGTGCAC (SEQ ID NO: 15) 417 AE004741 gyrA rev GCCCACGGCGATACCGCTGGA (SEQ ID NO: 16) ExoU exoU ExoU for CCGTTGTGGTGCCGTTGAAG (SEQ ID NO: 17) 135 U97065 II ExoU rev CCAGATGTTCACCGACTCGC (SEQ ID NO: 18) ExoU exoU ExoU for CCGTTGTGGTGCCGTTGAAG (SEQ ID NO: 19) 135 U97065 ExoU rev CCAGATGTTCACCGACTCGC (SEQ ID NO: 20) ExoS exoS ExoS for GCGAGGTCAGCAGAGTATCG (SEQ ID NO: 21) 119 AE004801 ExoS rev TTCGGCGTCACTGTGGATGC (SEQ ID NO: 22) ExoT exoT ExoT for AATCGCCGTCCAACTGCATGCG (SEQ ID NO: 23) 154 AE004444 ExoT rev TGTTCGCCGAGGTACTGCTC (SEQ ID NO: 24) GyrB gyrB GyrB for CCTGACCATCCGTCGCCACAAC (SEQ ID NO: 25) 329 AB005881 GyrB rev CGCAGCAGGATGAAGACGCC (SEQ ID NO: 26) OprI oprI OprI for GCTCTGGCTCTGGCTGCT (SEQ ID NO: 27) 197 AE004712 OprI rev AGGGCACGCTCGTTAGCC (SEQ ID NO: 28) Srv3 16S Srv3 for CGGNCCAGACTCCTACGGG (SEQ ID NO: 29) 204 AE004949 II rRNA Srv3 rev TTACCGCGGCTGCTGGCA (SEQ ID NO: 30) Pse carb- Pse for GCTAAATTACTATGATGCTGAG (SEQ ID NO: 31) 327 S46063, 1,2,3,4 Pse rev TATTGCCTTAGGAGTTGTCG (SEQ ID NO: 32) U14749 Oxa Oxa- OxaI for CAGAGAAGTTGGCGAAGTAAGAAT (SEQ ID NO: 33) 307 AF347074, III 5,7,10,11, OxaI rev AACCCACCCAACCCACCAT (SEQ ID NO: 34) U37105, 13,14,16, Z22590, 17,19,28 U59183 L38523, AF043100, AF060206, AF043381, AF231133 oxa- OxaII for GCTCGGCGCTATTTGAAGAA (SEQ ID NO: 35) 415 AJ295229, 2,3,15,20 OxaII rev GCGCAGCGTCCGAGTTGA (SEQ ID NO: 36) L07945, U63835, AF024602 Imp Imp- Imp for GACACTCCATTTACTGCTA (SEQ ID NO: 37) 160 X98393, 1,7,9,10, Imp rev ATTCAGATGCATACGTGGGGATAG (SEQ ID NO: 38) AY625689, 11 AF318077, AY033653, AB074434, AB074437,A B074433 Vim Vim-1,2 Vim for TGATACAGCGTGGGGTGCGAAAAA (SEQ ID NO: 39) 472 AJ291609, Vim rev GTGCCCCGGAATGACGAACTGTG (SEQ ID NO: 40) AF263519, AJ295229 Aac Aac(6′)-Ib Aac(6′)-Ib for CTCGAATGCCTGGCGTGTTTGA (SEQ ID NO: 41) 439 X60321, IV Aac(6′)-Ib rev GTGGTGGGGCGGAGAAGAAGC (SEQ ID NO: 42) AF043381, U59183, AF231133, AF315351, AF315786 Aac(6′)-II Aac(6′)-II for ACTGGTCTATTCCTCGCACTCCTG (SEQ ID NO: 43) 288 AF162771, Aac(6′)-II rev CCCCCATAACTCTTCGCCTCAT (SEQ ID NO: 44) M29695, AF318077 Aac(3)-Ia Aac(3)-Ia for GCCGGAGACTGCGAGAT (SEQ ID NO: 45) 241 U12338 Aac(3)-Ia rev GCAGTCGCCCTAAAACAAA (SEQ ID NO: 46) Aac(3)-Ib aac(3)-Ib for ACGCTTCAGGTGGCTAATC (SEQ ID NO: 47) 345 L06157 aac(3)-Ib rev ACAAAGTTAGGTGGCTCAATG (SEQ ID NO: 48) Aac(3)-II aac(3)-II for TTCCCCCAAGGCGTGACC (SEQ ID NO: 49) 424 AF466526 aac(3)-II rev GCATACGCGGAAGGCAATAAC (SEQ ID NO: 50) Aph Aph(3′)- Aph(3′)-IIb for GAAGAACTCGTCCAATAGCCTGAA (SEQ ID NO: 51) 224 X90856 IIb Aph(3′)-llb rev GCGACGCCTGCCTGCCAAATC (SEQ ID NO: 52) Aad aadA1 AadA1 for TATCAGAGGTAGTTGGCGTCAT (SEQ ID NO: 53) 440 AJ291609, AadA1 rev TTCAGGAACCGGATCAAAGAGT (SEQ ID NO: 54) AJ295229 aadA2 AadA2 for TCAGGAACCGGGTCAAAGAAT (SEQ ID NO: 55) 416 U12338 Aada2 rev GAGCGCCATCTGGAATCAAC (SEQ ID NO: 56) aadB AadB for CGGCACGCAAGACCTCAA (SEQ ID NO: 57) 241 AF078527, AadB rev GCTTGGTGGGCAGACGAA (SEQ ID NO: 58) AF133699 IV
[0087]
TABLE 2
Origin and source of the test collective
of 60 clinical P. aeruginosa isolates
ICU-
ICU-
ICU-
Internal
General
Cardiac
Other
Medicine
Surgery
Surgery
wards
All
Bronchoalveolar
1
1
lavage
Tracheal
5
9
18
1
33
sectretion
Swab
2
2
4
2
10
Pharynx/Nose
Sputum
3
4
7
Swab Wound
1
3
1
5
Faeces
1
1
2
Urine
2
2
Total
12
14
22
12
60
[0088]
TABLE 3
Antimicrobial susceptibilities of P. aeruginosa test collective
Number of
% of resistant
resistant isolates
isolates out
Antibiotic
out of 60
of 60
Levofloxacin
26
43
Ciprofloxacin
24
40
Gentamicin
22
37
Tobramycin
6
10
Amikacin
10
17
Piperacillin
21
35
Tazobac
20
33
Ceftazidim
20
33
Cefepim
19
32
Aztreonam
22
36
Imipenem
27
45
Colistin
0
0
[0089]
TABLE 4
Mutations found by array analysis in 60 P. aeruginosa isolates
Gene
mexR
nfxB
mexT
gyrA
parC
mucA
Mutation locus
80
208
327
377
384
115
303
305
197
212
248
240
362
440
Number of
2
6
24
24
22
1
3
9
13
10
19
3
2
4
isolates out of 60
[0090]
TABLE 5
Antibiotic resistance mediating genes found by
array analysis in 60 P. aeruginosa isolates
Gene
aadA
Aac(3)
Aac(6′)
Subtype
Imp
Vim
Oxa
1
2
aadB
Ia
Ib
II
Ib
II
exoS
exoT
exoU
Number of
8
1
17
5
1
4
4
2
7
6
0
47
47
13
isolates
[0091]
TABLE 6
Comparison of phenotypic resistance rate and cumulative resistance
prediction based on genotype determined by array analysis
Number of
Cumulative
resistant
% of
resistance
isolates
resistant
predicttion
out
isolates out
60 MIC
deduced
Antibiotic
of 60
of 60
[μg/ml]
from array
Levofloxacin
26
43
>4
52%
Ciprofloxacin
24
40
>2
Gentamicin
22
37
>8
45%
Tobramycin
6
10
>8
17%
Amikacin
10
17
>32
20%
Piperacillin
21
35
>64
38%
Tazobac
20
33
>64
Ceftazidim
20
33
>16
40%
Cefepim
19
32
>16
40%
Aztreonam
22
36
>16
Imipenem
27
45
>8
50%
Colistin
0
0
0%
[0092]
TABLE 7
Susceptibility profile for ciprofloxacin and tobramycin from 3 consecutive
Pseudomonas aeruginosa isolates from the same patient
Isolate 1
Isolate 2
Isolate 3
Antibiotic
S
R
R
Ciprofloxacin
S
S
R
Tobramycin
[0093]
TABLE 8
sequences of the capture probes and the positions of the respective SNPs
Sequence
Wild
position
type
Mutation
Description
Length
Gene
(Name)*
Probe sequence** (5′-3′)
N***
N****
*****
[bases]
mexR
165 mexR se
tcccaggtccc N caggttcag (SEQ ID NO: 59)
C
G
Gln55His
21
170 mexR se
tggcgtccc N ggtcctgcag (SEQ ID NO: 60)
A
C
Leu57Arg
20
208 mexR se
ggatcttcc N ggtgatcagt (SEQ ID NO: 61)
G
A
Arg70Gln
20
264 mexR se
cgctggtcc N tggggttg (SEQ ID NO: 62)
C
G
Ser88Arg
18
281 mexR se
aggaagagc N ggaagctgcg (SEQ ID NO: 63)
T
G
Gln94Pro
20
320 mexR se
gcctccgca N gctggtggat (SEQ ID NO: 64)
T
G
His107Pro
20
327 mexR se
atgatggc N tccgcatgctg (SEQ ID NO: 65)
C
A
Glu109Asp
20
377 mexR se
cttgttcc N ccggggtgag (SEQ ID NO: 66)
T
A
Val126Glu
19
384 mexR se
cagggtggc N tgttcctcc (SEQ ID NO: 67)
C
A
Gln128His
19
65 mexR se
ctggatgcgccggtccgcac (SEQ ID NO: 68)
CG ins
frameshift/
20
stop
65 mexR WT se
ctggatgcgcgtccgcac (SEQ ID NO: 69)
wild-type
18
69 mexR se
cgctctggatggcgcgtccg (SEQ ID NO: 70)
C ins
frameshift/
20
stop
69 mexR WT se
cgctctggatgcgcgtccg (SEQ ID NO: 71)
wild-type
19
80 mexR se
caatcgagcatcgctctgga (SEQ ID NO: 72)
T ins
frameshift/
20
stop
80 mexR WT se
caatcgagctcgctctgga (SEQ ID NO: 73)
wild-type
19
47-57 mexR se
gcgtccgcacccgccatcag (SEQ ID NO: 74)
Δ10N
frameshift/
20
stop
47-57 mexR WT se
tgctggaagaccgccatcag (SEQ ID NO: 75)
wild-type
20
261-272 mexR se
ctggaagctggggttgcgct (SEQ ID NO: 76)
Δ10N
frameshift
20
261-272 mexR WT se
gtcgctggggttgcgctcg (SEQ ID NO: 77)
wild-type
19
294-300 mexR se
ggatggccagcccgtgagga (SEQ ID NO: 78)
Δ10N
frameshift
20
294-3 00 mexR WT se
cagcccctcgtcggtgag (SEQ ID NO: 79)
wild-type
18
367-377 mexR se
ggcctgttcccggggcaaac (SEQ ID NO: 80)
Δ10N
frameshift/
20
stop
367-377 mexR WT se
ggggtgagcgggcaaaca (SEQ ID NO: 81)
wild-type
18
382-387 mexR se
gcaccagggtttccaccggg (SEQ ID NO: 82)
Δ10N
frameshift
20
382-387 mexR WT se
accagggtggcctgttccac (SEQ ID NO: 83)
wild-type
20
mexT
197 mexT se
cgcgggtca N gctgcgttcg (SEQ ID NO: 84)
G
C
Leu65Val
20
212 mexT se
acagtttct N tgcggcgcgg (SEQ ID NO: 85)
C
T
Glu71Lys
20
733 mexT se
aggtcgccgg N gaaggacacca (SEQ ID NO: 86)
C
A
Ala245Ser
22
413 mexT se
atcaatagaagttggcgcg (SEQ ID NO: 87)
ΔT
frameshift/
19
stop
413 mexT WT se
atcaatagatagttggcgcg (SEQ ID NO: 88)
wild-type
20
nfxB
124 nfxB se
ccgcagaagc N gtgcagggt (SEQ ID NO: 89)
G
T
Arg41Ser
20
260 nfxB se
tgggtgagg N gttccttgat (SEQ ID NO: 90)
T
G
His87Pro
20
105 nfxB se
ggccttgctctacgccggccg (SEQ ID NO: 91)
C ins
frameshift
21
105 nfxB WT se
ggccttgcttacgccggccg (SEQ ID NO: 92)
wild-type
20
115 nfxB se
ggtgcagggggccttgct (SEQ ID NO: 93)
ΔT
frameshift/
18
stop
115 nfxB WT se
ggtgcagggtggccttgct (SEQ ID NO: 94)
wild-type
19
188 nfxB se
tgatctggttccagtacgg (SEQ ID NO: 95)
C ins
frameshift
19
188 nfxB WT se
tgatctggttcagtacgg (SEQ ID NO: 96)
wild-type
18
303 nfxB se
tccgggcggactggaatacc (SEQ ID NO: 97)
ΔT
frameshift
20
303 nfxB WT se
tccgggcggtactggaatacc (SEQ ID NO: 98)
wild-type
21
305 nfxB se
tccgggcgggtactggaata (SEQ ID NO: 99)
G ins
frameshift
20
305 nfxB WT se
tccgggcggtactggaata (SEQ ID NO: 100)
wild-type
19
gyrA
248 gyrA A
tagaccgcg N tgtcgccgtg (SEQ ID NO: 101)
G
A
Ser83Ile
20
260 gyrA A
cacgatggtg N cgtagaccgc (SEQ ID NO: 102)
T
G
Asp87Tyr
21
parC
240 parC A
tagcaggcc N agtcgccgtg (SEQ ID NO: 103)
G
A
Ser80Leu
20
251 parC A
ccatggcct N gtagcaggcc (SEQ ID NO: 104)
C
T
Glu84Lys
20
exoS
exoS se
cttcaccaggccatccgc (SEQ ID NO: 105)
18
exoS as
gcggatggcctggtgaag (SEQ ID NO: 106)
18
exoU
exoU se
gaaatcaccgcgctcgc (SEQ ID NO: 107)
17
exoU as
gcgagcgcggtgatttc (SEQ ID NO: 108)
17
exoT
exoT se
aagtgctccaccaggccatc (SEQ ID NO: 109)
20
exoT as
gatggcctggtggagcactt (SEQ ID NO: 110)
20
oprI
oprI se
cgtcttcggtagcggtcag (SEQ ID NO: 111)
19
oprI as
ctgaccgctaccgaagacg (SEQ ID NO: 112)
19
gyrB
gyrB se
ctgaagtggatgttgctgaaggtc (SEQ ID NO: 113)
24
gyrB as
gaccttcagcaacatccacttcag (SEQ ID NO: 114)
24
16S rDNA
srv3 se
ttactgcccttcctcccaactta (SEQ ID NO: 115)
19
srv3 as
taagttgggaggaagggcagtaa (SEQ ID NO: 116)
19
mucA
359 mucA se
gtcccctgtt N cgccatttgc (SEQ ID NO: 117)
C
T
Thr120Asn
21
362 mucA se
gtggtcccct N ttgcgccatt (SEQ ID NO: 118)
C
T
Thr121Asn
21
377 mucA se
agggcgatc N gcggggtggtc (SEQ ID NO: 119)
C
T
Leu126Gln
21
431 mucA se
gccccctgct N ttcgctgtag (SEQ ID NO: 120)
C
T
Ala144Glu
21
434 mucA se
ggcgccccct N ctcttcgctg (SEQ ID NO: 121)
C
T
Pro145Gln
21
446 mucA se
gtgatcacct N cggcgccccc (SEQ ID NO: 122)
C
T
Thr149Asn
21
167 mucA se
agggtaggctccgcggtgcat (SEQ IS NO: 123)
C ins
frameshift/
21
stop
167 mucA WT se
agggtaggctcgcggtgcat (SEQ ID NO: 124)
wild-type
20
371 mucA se
atctgcggggggtcccctgt (SEQ ID NO: 125)
ΔT
frameshift/
20
stop
371 mucA WT se
atctgcggggtggtcccctgt (SEQ ID NO: 126)
wild-type 21
407 mucA se
ccagcacggcacgggcctttc (SEQ ID NO: 127)
A ins
frameshift/
21
stop
407 mucA WT se
ccagcacggccgggcctttc (SEQ ID NO: 128)
wild-type
20
440 mucA se
acctgcggcgcccctgctct (SEQ ID NO: 129)
ΔC
frameshift/
20
stop
440 mucA WT se
acctgcggcgccccctgctct (SEQ ID NO: 130)
wild-type 21
471 mucA se
cgggtatcgcatggacgagga (SEQ ID NO: 131)
A ins
frameshift/
21
stop
471 mucA WT se
cgggtatcgctggacgagga (SEQ ID NO: 132)
wild-type
20
aph(3′)
aph(3′)-IIb se
gaagaactcgtccaatagcctgaa (SEQ ID NO: 133)
24
aph(3′)-IIb as
ttcaggctattggacgagttcttc (SEQ ID NO: 134)
24
aadB
aadB se
atgtgctttgtaggccagtcca (SEQ ID NO: 135)
22
aadB as
tggactggcctacaaagcacat (SEQ ID NO: 136)
22
aadA
aadA1 se
tttcatcaagccttacggtcacc (SEQ ID NO: 137)
23
aadA1 as
ggtgaccgtaaggcttgatgaaa (SEQ ID NO: 138)
23
aadA2 se
ggtgacttctatagcgcggagc (SEQ ID NO: 139)
22
aadA2 as
gctccgcgctatagaagtcacc (SEQ ID NO: 140)
22
aac(6′)
aac(6′)-Ib se
catacccaatcggctctccat (SEQ ID NO: 141)
21
aac(6′)-Ib as
atggagagccgattgggtatg (SEQ ID NO: 142)
21
aac(6′)-II se
aacgatgtgcggccggt (SEQ ID NO: 143)
17
aac(6′)-II as
accggccgcacatcgtt (SEQ ID NO: 144)
17
aac(3)
aac(3)-II se
gttattgccttccgcgtatgc (SEQ ID NO: 145)
21
aac(3)-II as
gcatacgcggaaggcaataac (SEQ ID NO: 146)
21
aac(3)-Ib se
ctattgctgttccgcggtca (SEQ ID NO: 147)
20
aac(3)-Ib as
tgaccgcggaacagcaatag (SEQ ID NO: 148)
20
aac(3)-Ia se
aactcacgaccgaaaagatcaaga (SEQ ID NO: 149)
24
aac(3)-Ia as
tcttgatcttttcggtcgtgagtt (SEQ ID NO: 150)
24
pse
417 pse se
atcacttgt N gtcatagttg (SEQ ID NO: 151) T
A
pse-1,2,3
20
C
pse-4
555 pse se
caaatcacc N agcttaccttca (SEQ ID NO: 152)
T
A
pse-4
22
C
pse-1,2,3
bla-imp
imp se
gagaattaagccactctattcc (SEQ ID NO: 153)
imp-1,7,9,
22
10,11
imp as
ggaatagagtggcttaattctc (SEQ ID NO: 154)
imp-1,7,9,
22
10,11
bla-vim
vim se
atcaacgccgccgacgc (SEQ ID NO: 155)
vim-1,2,4
17
vim as
gcgtcggcggcgttgat (SEQ ID NO: 156)
vim-1,2,4
17
oxa
428 oxa1 se
gatattctgg N tgccatagga (SEQ ID NO: 157)
A
T
oxa-10,13,14,
21
(group
C
16,17,19,28
1)
oxa-11
521 oxal se
atttatttaaa N atagagactc (SEQ ID NO: 158)
G
A
oxa-13,19,28
22
T
oxa-10,11,14,
16,17
oxa
449 oxa2 se
cttgtcgaagga N cggcgttgc (SEQ ID NO: 159)
A
T
oxa-2,3
22
(group
C
oxa-15
2)
oxa2 se
gctcctgcgccgagattgc (SEQ ID NO: 160)
oxa-2,15
19
oxa2 as
gcaatctcggcgcaggagc (SEQ ID NO: 161)
oxa-2,15
19
oxa2 3 se
ctgttcttgtgccgcgatagc (SEQ ID NO: 162)
oxa-3
21
oxa2 3 as
gctatcgcggcacaagaacag (SEQ ID NO: 163)
oxa-3
21
*se: sense probe; as: anti-sense probe; WT: wild-type
**N: Variable nucleotide in a capture probe for a SNP position, can be eiter A, T, G or C. On the array all four possible nucleotides are each represented with a capture probe. The indicated nucleotides are based on the capture probe sequence.
***N represents the respective nucleotide in the wild-type strain P. aeruginosa PAO1
****N represents the respective nucleotide for a SNIP position in the mutant sequence; Δ: deletion; ins: insertion
*****For SNPs, deletions or insertions either the respective amino acid change, frameshift, occurance of a premature stop codon or change of mutated gene compared to the parental gene is indicated.
[0094] | The present invention relates in general to the detection of antibiotic resistance determinants in Pseudomonas aeruginosa ( P. aeruginosa ). The present invention discloses a micro-array for the detection of antibiotic resistance determinants and mutations in said organism, a method for the detection of said determinants and a kit. This micro-array concept offers the rapid sensitive and specific identification of antibiotic resistance profiles. | 2 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electrical resistance element of the molybdenum silicide type.
2. Description of the Related Art
Such elements have long been known in different forms with regard to their different alloy contents. Kanthal AB of Sweden are manufacturers of such elements. These types of elements are referred to as molybdenum silicide-type elements, which have long been used to heat ovens and different kinds of surfaces, such as a radiating surface that radiates onto an object, or cooker plates, or other surfaces.
Molybdenum silicide elements are produced in different forms. A typical form is a so-called leg element, which comprises two legs that extend between two electrical conductors or terminals at one of their ends. The legs are joined with an arcuate or curved part at their other ends. The leg elements can consist of one, two, or more legs. Two-legged elements, or multi-leg elements, include one or more curved parts that extend between the conductors. The leg constitutes a glow zone, i.e., that part of the element that glows when supplied with electric current, and therewith delivers heat to an object.
One problem experienced with industrial furnaces, ovens, and the like resides in the difficulty at times of maintaining a sufficiently uniform temperature distribution in a furnace space, or in achieving sufficiently uniform thermal radiation from a radiating surface. An uneven temperature distribution or uneven radiation will mean that the space or the object to be heated will not be heated uniformly, which can be highly problematic.
A concrete example is when liquid-metal ladles are to be pre-heated. Uneven heating of a ladle presents a problem when using resistance elements, as the bottom of the ladle will not be as hot as the inner walls of the ladle.
The known method of attempting to resolve this problem involves the installation of a number of elements or groups of elements that can be controlled individually, so that different elements have delivered power of different high magnitudes.
The present invention solves the problem caused by uneven heating.
SUMMARY OF THE INVENTION
Accordingly, the present invention relates to an electrical resistance element of the molybdenum silicide type that includes two terminals for the supply of electric current. At least one connecting member extends between the terminals and includes a glow zone. The glow zone has different diameters along different connecting member sections.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in more detail, partly with reference to the embodiments of the invention shown in the accompanying drawings, in which
FIGS. 1 , 2 , and 3 show different forms of two-legged heating elements, and
FIG. 4 shows a four-legged heating element.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The respective relative measurements of certain parts of the elements have been shown in the drawings for the sake of clarity. It will be understood, however, that these measurements have been given only by way of example. In the Figures, reference character Lu indicates the length of the terminals and reference character Le indicates the length of the glow zone. Reference characters Le 1 , Le 2 , and Le 3 indicate the lengths of different sections of the glow zone of the element, and reference character “a” indicates a distance.
According to one embodiment, an electric resistance element of the present type includes two electricity supply terminals 1 , 2 , and two legs 3 , 4 , which extend between the terminals and which include a glow zone.
According to the present invention, the glow zone has different diameters along different sections of the legs.
This means that the heat developed will differ in magnitude along different sections of the element, due to the disparity in the amperage or current intensity in each applicable cross-sectional area of the element. The invention thus allows an element to be designed in accordance with the heating requirements that exist along the full extent of the element.
An inventive element of the kind illustrated in FIG. 1 can be used in the case of the above example concerning a ladle whose bottom is not heated sufficiently in relation to the inner walls of the ladle when using a known element. The inventive element has terminals having a diameter of 24 millimeters, and two legs 3 , 4 whose upper parts are 12 millimeters in diameter and lower parts which are 10 millimeters in diameter. Such an element will become hotter at its narrower, lower, part. This higher temperature will make that part of the object located close to this section of the ladle much hotter.
According to one embodiment of the invention, the element has two legs with only one curved part 3 a between the terminals 1 , 2 ; see FIG. 1 .
According to another embodiment of the invention, the element has four legs, see FIG. 4 , or more, and includes two curved parts 4 a , 5 a , or more, between the terminals 1 , 2 .
An element of the present kind may also be formed with only one leg, for example a straight leg that has a terminal at each end.
FIG. 2 illustrates an embodiment in which the glow zones have mutually different diameters along different sections 6 , 7 , 8 of the legs, where the diameters of respective sections become smaller with increasing distance of the respective sections 6 , 7 , 8 from the terminals 1 , 2 .
FIG. 3 illustrates an embodiment in which the glow zone has mutually different diameters along different sections 9 , 10 , 11 of the legs 3 , 4 , where the diameters of the sections decrease and increase along the legs. The same design can, of course, be utilized in elements that have two or more legs. In the FIG. 3 embodiment, the sections 9 and 11 have a diameter of 10 millimeters and the section 10 has a diameter of 12 millimeters.
In the case of certain applications, the glow zone will preferably have different diameters along different leg sections, wherein the diameters of respective sections are smaller the closer the sections are to the terminals. In the FIG. 4 embodiment, the sections 12 , 13 have a diameter of 8 millimeters, while the sections 14 - 17 have a diameter of 9 millimeters.
Although only elements that lie in a single plane are shown in the Figures, it will be understood that an element may include two or more legs, where one, two, or more legs, or parts thereof, define an angle with a plane in which the terminals lie.
The elements may be designed to heat a volume in a known manner, or to form a radiating surface. Moreover, the elements may be designed, and possibly supported, for mounting vertically, horizontally, or at another angle to the horizontal plane.
The different embodiments illustrated in the drawings are, of course, exemplifying embodiments with regard to shape and diameters. As will be obvious to those skilled in this art, elements can be given generally any shape and form, with mutually different diameters that provide the heating effect desired for a particular application. The present invention is therefore not limited to any particular element design, as long as different sections have different diameters.
The present invention shall not therefore be considered to be restricted to the described and illustrated embodiments, since variations and modifications can be made within the scope of the accompanying claims. | The present invention relates to an electrical resistance element of the molybdenum silicide type that includes two terminals ( 1, 2 ) for the supply of electric current and at least one leg ( 3 ) which extends between the terminals and which includes a glow zone. The invention is characterized in that the glow zone has different diameters along different sections ( 6 - 11, 14 - 17 ) of the leg ( 3; 4, 5 ). | 7 |
CROSS-REFERENCE TO PRIOR APPLICATIONS
This application is a national Stage Patent Application of PCT International Patent Application No. PCT/US2012/043482, which was filed on Jun. 21, 2012 under 35 U.S.C. §371 and claims priority of both U.S. Patent Application No. 61/500,624, filed on Jun. 24, 2011 and U.S. patent application Ser. No. 13/529,110, filed on Jun. 21, 2012, which are all hereby incorporated by reference in their entirety.
BACKGROUND OF THE INVENTION
The present invention relates to plasma generators, and more particularly to systems having a resonant cavity for generating a plasma therein.
In recent years, microwave technology has been applied to generate various types of plasma. In some applications, igniting and sustaining plasma requires a high power microwave generator. The existing microwave techniques are not suitable, or at best, highly inefficient due to one or more of the following drawbacks. First, the existing systems lack proper scalability, where scalability refers to the ability of a system to handle varying amounts of microwave input power in a graceful manner or its ability to be enlarged/reduced to accommodate the variation of the input power. For instance, the required microwave input power may vary depending on the types, pressure, and flow rates of the gas to be converted into plasma. Second, the economics of scale for a magnetron increases rapidly as the output power increases. For instance, the price of a 10 KW magnetron is much higher than the price of ten 1 KW magnetrons. Thus, there is a need for a plasma generating system that has high scalability and is cheaper than currently available plasma generating systems without compromising the output power.
SUMMARY OF THE INVENTION
In one embodiment of the present disclosure, a microwave resonant cavity includes: a sidewall having a generally cylindrical hollow shape and formed of a material opaque to a microwave; a gas flow tube disposed inside the sidewall, formed of a material transparent to a microwave, and having a longitudinal axis substantially parallel to a longitudinal axis of the sidewall; a plurality of microwave waveguides, each said microwave waveguide having a longitudinal axis substantially perpendicular to the longitudinal axis of the sidewall and having a distal end secured to the sidewall and aligned with a corresponding one of a plurality of holes formed on the sidewall; a top plate formed of a material opaque to a microwave and secured to one end of the sidewall; and a sliding short circuit. The sliding circuit includes: a disk formed of a material opaque to a microwave and slidably mounted between the sidewall and the gas flow tube, the disk having an outer rim snuggly fit into the sidewall and a hole into which the gas flow tube being snuggly fit; and at least one bar disposed inside the sidewall and arranged parallel to the longitudinal axis of the sidewall. By moving the bar along the longitudinal direction of the sidewall, the space defined by the top plate, sidewall, and the disk is adjusted to form a microwave resonant cavity inside the gas flow tube.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of a plasma generating system in accordance with one embodiment of the present invention.
FIG. 2 is an exploded perspective view of the microwave resonant cavity in FIG. 1 .
FIGS. 3A-3C are top views of alternative embodiments of the microwave resonant cavity in FIG. 2 .
FIGS. 4A-4C are perspective views of alternative embodiments of the microwave resonant cavity in FIG. 1 .
FIG. 5 is a schematic cross sectional view of an alternative embodiment of the microwave resonant cavity in FIG. 2 .
FIG. 6 is a schematic cross sectional view of an alternative embodiment of the microwave resonant cavity in FIG. 2 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 is a schematic diagram of a system 10 for generating microwave plasma in accordance with one embodiment of the present invention. As illustrated, the system 10 may include: a microwave resonant cavity 26 ; microwave supply units 11 a - 11 c for providing microwaves to the microwave resonant cavity 26 ; and waveguides 24 a - 24 c for transmitting microwaves from the microwave supply units 11 a - 11 c to the microwave resonant cavity 26 , where the microwave resonant cavity 26 receives a gas and/or gas mixture from a gas tank 28 or another source such as flue gas.
The microwave supply unit 11 a provides microwaves to the microwave resonant cavity 26 and may include: a microwave generator 12 a for generating microwaves; a power supply 13 a for supplying power to the microwave generator 12 a ; and an isolator 15 a having a dummy load 16 a for dissipating reflected microwaves that propagate toward the microwave generator 12 a and a circulator 18 a for directing the reflected microwaves to the dummy load 16 a.
In one embodiment, the microwave supply unit 11 a further includes a coupler 20 a for measuring fluxes of the microwaves; and a tuner 22 a for reducing the microwaves reflected from the microwave resonant cavity 26 . The components of the microwave supply unit 11 a shown in FIG. 1 are well known and are listed herein for exemplary purposes only. Also, it is possible to replace the microwave supply unit 11 a with a system having the capability to provide microwaves to the microwave resonant cavity 26 without deviating from the present invention. A phase shifter may be mounted between the isolator 15 a and the coupler 20 a.
The microwave supply units 11 b and 11 c are shown to have similar components as the microwave supply units 11 a . However, it is noted that the microwave supply units 11 b and 11 c may have components different from those of the unit 11 a , insofar as they can generate and deliver microwaves to the waveguides 24 b and 24 c , respectively.
FIG. 2 is an exploded perspective view of the microwave resonant cavity 26 in FIG. 1 . As depicted, the microwave resonant cavity (shortly, cavity hereinafter) 26 includes a top plate 41 having an inlet port 51 for receiving gas 53 from the gas tank 28 ; a bottom plate 43 having an outlet port (or, outlet hole) 44 for discharging gas therethrough; and a sidewall 42 connected to the distal ends of the waveguides 24 a - 24 c . The distal end of the waveguide 24 a is secured to the sidewall 42 so that the microwave energy flowing through the proximal end 40 a of the waveguide 24 a enters into the sidewall 42 . Likewise, the microwave energy flowing through the proximal ends 40 b and 40 c of the waveguides 24 b and 24 c enters the sidewall 42 . The top plate 41 , sidewall 42 , and bottom plate 43 may be formed of any suitable material, such as metal, that is opaque to the microwave. The cavity 26 also includes a gas flow tube 46 that is transparent to the microwave and preferably formed of quartz.
The top and bottom ends of the gas flow tube 46 are sealed to the top plate 41 and the bottom plates 43 of the cavity 26 , respectively, so that the gas entered into the tube 46 through the inlet port 51 is excited into plasma and exits through the outlet port 44 of the bottom plate 43 . The microwave energy received through the waveguides 24 a - 24 c excites the gas into plasma when the gas flows through the gas flow tube 46 .
The cavity 26 may also include a sliding short 48 having a disk 49 and bars 50 . The disk 49 is dimensioned to slidably fit into the space between the inner surface of the sidewall 42 and the outer surface of the gas flow tube 46 , and formed of material opaque to the microwave, preferably metal. During operation, the microwaves discharged from the distal ends of the waveguides 24 a - 24 c form an interference pattern in the gas flow tube 46 . As the user slides the bars 50 up and down along the longitudinal direction 56 of the cavity 26 , the distance between the disk 49 and the top plate 41 is changed so that the interference generates a peak amplitude region in the gas flow tube 46 , i.e., the impedance matching may be obtained by adjusting the location of the disk 49 relative to the top plate 41 . It is noted that the bars may be attached to a suitable tuning mechanism, such as a micrometer fixed to the outer surface of the bottom plate 43 so that the user can tune the impedance at high precision Optionally, a motor attached to the bars 50 may be used for an automated control.
It is noted that the microwaves generated by the three microwave supply units 11 a - 11 c are combined in the gas flow tube 46 . As such, if the microwave supply units are identical, the maximum intensity of microwave field within the gas flow tube 46 would be the same as the intensity generated by one microwave supply unit that has the output power three times as large as the microwave supply unit 11 a . This feature provides two advantages; scalability and cost reduction in manufacturing a microwave supply unit. The operator of the system 10 may selectively turn on the microwave supply units 11 a - 11 c so that the intensity of the microwave field in the gas flow tube 46 may be varied. For instance, the microwave intensity for igniting the plasma in the gas flow tube 46 may vary depending on the types of gas 53 . The operator may optimize the microwave intensity in the gas flow tube 46 by selectively turning on the microwave supply units 11 a - 11 c . It is noted that the system 10 has only three microwave supply unit. However, it should be apparent to those of ordinary skill in the art that the system may include any other suitable number of microwave supply units.
The price of the microwave generator 12 a , especially the magnetron, increases rapidly as its power output increases. For instance, the price of ten magnetrons of the commercially available microwave oven is considerably lower than that of one high power magnetron which has an output power ten times that of the microwave oven. Thus, the multiple microwave generators feature of the system 10 allows the designer to build a low cost microwave generating system without compromising the total maximum power.
FIGS. 3A-3C are top views of alternative embodiments 60 , 70 , and 80 of the cavity sidewall 42 in FIG. 2 . As depicted, the sidewall may have a suitable polygonal shape, such as rectangle, hexagon, or octagon, where a waveguide may be fixed to each side of the polygon. The phases of the microwaves exiting from two adjacent waveguides may be differentiated so that the interference between the microwaves generates the maximum intensity in the gas flow tubes 62 , 72 , and 82 . It is noted that gas flow tubes 62 , 72 , and 82 may have other suitable cross sectional geometry, such as rectangle, hexagon, or octagon. It is further noted that the angle θ (shown in FIG. 1 ) between two adjacent waveguides may be adjusted to optimize the interference between two microwaves.
FIG. 4A is a perspective view of an alternative embodiment 100 of the cavity 26 in FIG. 1 . For brevity, only the sidewall and waveguides are show in FIG. 4 A. As depicted, the cavity 100 is similar to the cavity 26 in FIG. 1 , with the difference that the waveguides 102 a - 102 c are e-plane waveguides.
FIGS. 4B and 4C are perspective views of alternative embodiments 114 and 124 of the cavity 26 in FIG. 1 . As depicted, the cavities 114 and 124 are similar to the cavity 26 , with the differences that the locations of the waveguides 112 a - 112 c and 122 a - 122 c relative to the sidewalls of the cavities 114 and 124 are different. The locations of the waveguides are determined to optimize the interference pattern in the gas flow tubes (not shown in FIGS. 4B-4C for brevity) disposed within the cavities 114 and 124 .
FIG. 5 is a schematic cross sectional view of an alternative embodiment 200 of the microwave resonant cavity 26 in FIG. 2 . As depicted, the cavity 200 includes a top plate 241 having an inlet hole 243 for receiving gas from the gas tank 28 (not shown in FIG. 5 ); a sidewall 242 connected to the distal ends of the waveguides 224 a - 224 b ; a gas flow tube 246 having a bottom hole 244 for discharging gas therethrough; and sliding short circuit 248 having a disk 249 and bars 250 . Since the materials and functions of the components of the cavity 200 are similar to those of their counterparts of the cavity 26 , the detailed description is not repeated. The difference between the cavities 26 and 200 is that the cavity 200 does not have a bottom plate while the cavity 26 includes the bottom plate 43 .
FIG. 6 is a schematic cross sectional view of an alternative embodiment 300 of the cavity 26 in FIG. 2 . As depicted, the cavity 300 is similar to the cavity 26 , with the difference that the top and bottom portions of the gas flow tube 346 protrude outside the top plate 341 and the bottom plate 343 , respectively. The gas flow tube 346 includes a top hole 343 and a bottom hole 344 for receiving and discharging the gas therethrough. Alternatively, the gas flow tube 360 may have a gas inlet port 360 in place of the hole 343 , where the inlet port 360 is angled with respect to the longitudinal axis of the gas flow tube 346 to impart swirling motion to the injected gas.
It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims. | A microwave resonant cavity is provided. The microwave resonant cavity includes: a sidewall having a generally cylindrical hollow shape; a gas flow tube disposed inside the sidewall and having a longitudinal axis substantially parallel to a longitudinal axis of the sidewall; a plurality of microwave waveguides, each microwave waveguide having a longitudinal axis substantially perpendicular to the longitudinal axis of the sidewall and having a distal end secured to the sidewall and aligned with a corresponding one of a plurality of holes formed on the sidewall; a top plate secured to one end of the sidewall; and a sliding short circuit having: a disk slidably mounted between the sidewall and the gas flow tube; and at least one bar disposed inside the sidewall and arranged parallel to the longitudinal axis of the sidewall. | 7 |
[0001] This application claims the benefit under 35 U.S.C. 119(e) of the filing date of Provisional U.S. Application Ser. No. 60/784,422, entitled Method and Apparatus for Attaching Soft Tissues to Bone, filed on Mar. 20, 2006, and of the filing date of Provisional U.S. Application Ser. No. 60/854,178, entitled Methods and Systems for Material Fixation, filed on Oct. 24, 2006, and of the filing date of Provisional U.S. Application Ser. No. 60/898,946, entitled Devices, Systems and Methods for Material Fixation, filed on Jan. 31, 2007. All of these prior provisional applications are expressly incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates generally to devices, systems and methods for material fixation. More specifically, the present invention relates to a soft tissue or bone-to-bone fixation system that permits a practitioner to repair many soft tissue injuries, such as an Anterior Cruciate Ligament (ACL) injury.
[0003] One of the most common needs in orthopedic surgery is the fixation of tendon to bone. The fixation of diseased tendons into a modified position is called tenodesis and is commonly required in patients with injury to the long head of the biceps tendon in the shoulder. In addition, tendons which are torn from their insertion site into bone also frequently require repair. This includes distal biceps tendon tears, rotator cuff tears, and torn flexor tendons in the hand. Tendons are also frequently used in the reconstruction of unstable joints. Common examples include anterior cruciate ligament and collateral ligament reconstructions of the knee, medial and lateral elbow collateral ligament reconstructions, ankle collateral ligament reconstruction, finger and hand collateral ligament reconstructions and the like.
[0004] Traditional techniques that are used to fix tendon to bone suffer from a number of limitations as a result of the methodology used, including the use of a “keyhole” tenodesis, pull-out sutures, bone tunnels, and interference screw fixation. The “keyhole” tenodesis requires the creation of a bone tunnel in the shape of a keyhole, which allows a knotted tendon to be inserted into the upper portion, and subsequently wedged into the lower narrower portion of the tunnel where inherent traction on the tendon holds it in place. This technique is challenging as it is often difficult to sculpt the keyhole site and insert the tendon into the tunnel. In addition, if the tendon knot unravels in the postoperative period, the tendon will slide out of the keyhole, losing fixation.
[0005] Another traditional form of tendon fixation is the use of the “pull-out stitch.” With this technique, sutures attached to the tendon end are passed through bone tunnels and tied over a post or button on the opposite side of the joint. This technique has lost favor in recent years due to a host of associated complications, which include wound problems, weak fixation strength, and potential injury to adjacent structures.
[0006] The most common method of fixation of tendon to bone is the use of bone tunnels with either suture fixation, or interference screw fixation. The creation of bone tunnels is relatively complicated, often requiring an extensive exposure to identify the margins of the tunnels. Drill holes placed at right angles are connected using small curettes. This tedious process is time-consuming and fraught with complications, which include poor tunnel placement and fracture of the overlying bone bridge. Graft isometry, which is easy to determine with single point fixation, is difficult to achieve because the tendon exits the bone from two points. After creation of tunnels, sutures must be passed through the tunnels to facilitate the passage of the tendon graft. Tunnels should be small enough to allow good tendon-bone contact, yet large enough to allow for graft passage without compromising the tendon. This portion of the procedure is often time-consuming and frustrating to a surgeon. Finally, the procedure can be compromised if the bone bridge above the tunnel breaks, resulting in loss of fixation. The technique restricts fixation to the strength of the sutures, and does not provide any direct tendon to bone compression.
[0007] More recent advances in the field of tendon fixation involve the use of an internally deployed toggle button, for example, the ENDOBUTTON, and the use of interference screws to provide fixation. The ENDOBUTTON allows the fixation of tendon into a bone tunnel by creating an internally deployed post against a bony wall. While this technique eliminates the need for secondary incisions to place the post, the fixation strength is limited to suture strength alone. This technique does not provide direct tendon to bone compression; as such this technique may slow healing and lead to graft tunnel widening due to the “bungee effect” and “windshield wiper effect”. As a result, this technique has limited clinical applications and is used primarily for salvage when bone tunnels break or backup fixation is important.
[0008] The use of the interference screw is the most notable advance in the fixation of tendon to bone. The screw is inserted adjacent to a tendon in a bone tunnel, providing axial compression between the screw threads and the bony wall. Advantages include acceptable pull-out strength and relative ease of use. Aperture fixation, the ability to fix the tendon to bone at its entrance site, is a valuable adjunct to this technique as it minimizes graft motion and subsequent tunnel widening. Some disadvantages related to soft tissue interference screws are that they can be difficult to use, and can also cut or compromise the tendon during implantation.
[0009] The newest generation interference screw allows the ability to provide tendon to bone fixation with limited exposure. For example, the BIO-TENODESIS SCREW (Arthrex, Inc.) allows the tensioning and insertion of tendon into bone, followed by insertion of an adjacent soft tissue interference screw. While this screw system provides advantages in the insertion of tendon into bone in cases when a pull through stitch is not available, it is still limited by the potential for tendon rotation or disruption as the screw compresses the tendon. The surgical technique is also complicated, typically requiring two or more hands for insertion, making it difficult to use the system without assistance during arthroscopic or open procedures. Finally, the use of the screw requires preparation of the tendon end, which can be difficult, time consuming, and can also require conversion of an arthroscopic procedure to open.
[0010] Focusing particularly on the ACL, current ACL repairs utilizing soft tissue for the replacement graft are either difficult to perform or they result in less than favorable outcomes due to their relatively low tendon-to-bone fixation. Existing ACL reconstruction techniques that have acceptable outcomes (high tendon-to-bone fixation) involve extra operating room time and surgeon effort due to the requirement of multiple drill holes, external guides and fixtures for the drill holes, and multiple assistants. Moreover, these approaches to not closely replicate the native ACL in its anatomy or physiology.
[0011] Two important factors in replicating the native ACL are aperture compression and tendon length. Compressing the tendons at the aperture of the femoral tunnel will improve the healing process by increasing the intimate contact between the tendon and the bone. A study shows that without intimate contact between the tendon and the bone, the result is a graft having less well organized fibrous tissue and lower pull-out strength. The stiffness of the repair is also important to replicate the native ACL. Graft stiffness is decreased by the length of tendon between the fixation points.
[0012] Currently, two different sources are utilized for the tissue that replaces the injured native ACL. When the new tissue comes from the patient's own body, the new graft is referred to as an “autograft”, and when cadaveric tissue is used, the new graft is referred to as an “allograft”. The most common autograft ACL reconstruction performed currently is the bone-patellar-tendon-bone (BTB) graft. The BTB graft with an interference screw is used more often because it more accurately replicates the native ACL due to its aperture compression at the tibial tunnel aperture. However, BTB reconstructions result in an increased rate of anterior knee pain post-surgically for periods of up to three years after the reconstruction. Additionally, the harvest procedure for the BTB autograft is invasive and can be difficult to perform. Alternatively, the hamstring tendon autograft ACL reconstruction technique does not result in any significant post-surgical pain, and the harvest procedure is not minimally invasive. The reason that the hamstring tendon autograft procedure is not more frequently used in ACL reconstructions is that the fixation of the hamstring tendons to the femur an tibia, using prior art techniques, is not as strong as the fixation of the BTB autografts.
[0013] Many systems have addressed some of the problems associated with ACL reconstruction using hamstring tendons, but there is not any system which addresses them all. The TriTis® system available from Scandius attempts to more accurately replicate the native ACL by adding material to take up space in the tibial tunnel, resulting in more intimate contact between the tendon and the bone. However, to insert the device into the femoral tunnel, the cross sectional area must be less than the cross sectional area of the hole. There is no real compression of tendon to bone. The TriTis system also requires additional drill holes, accessories, and people to perform the procedure.
[0014] The IntraFix® system available from Mitek attempts to more accurately replicate the native ACL by using a screw to spread apart an integral four quadrant sheath. This acts to compress the four tendon strands against the bone. The system is easier to use than other alternatives, and does not need additional drill holes. However, it does require additional accessories, additional people to perform the procedure, and the four quadrant design does not accommodate certain allografts with two tendon strands, such as the tibialis.
[0015] The WasherLoc™ system, available from Arthrotek, gives increased strength, compared to other prior art systems, but does not accurately replicate the native ACL. The tendons are sized to the hole, but not compressed to the walls. There is also a greater distance between fixation points with this system, which can decrease the stiffness of the repair.
[0016] Interference screws such as the RCI™ Screw available from Smith & Nephew are easy to use and provide compression of tendon to bone at the tibial tunnel aperture. However, the pull out strength and stiffness of the repair are significantly lower than is the case for other prior art systems.
[0017] Thus, although there are many conventional techniques used for the fixation of tendon to bone, each having some advantages, the disadvantages of each such technique presents a need in the art for a simple and universal technique to fixate tendon to bone such that the device is easy to use, the process is simple to follow, and the result is a firm and secure tendon to bone fixation with minimal negative effect on the tendon. Further, such device should be easy to manufacture, universally applied to different tendon to bone sites, and require minimal effort to understand and use in practice.
SUMMARY OF THE INVENTION
[0018] The present invention is a system which is particularly adapted to improve the tendon-to-bone fixation of hamstring autografts, as well as other soft tissue ACL reconstruction techniques. The system is easy to use, requires no additional accessories, uses only a single drill hole, and can be implanted by one person. Additionally, it replicates the native ACL by compressing the tendons against the aperture of the tibial tunnel, which leads to a shorter graft and increased graft stiffness. It is adapted to accommodate single or double tendon bundle autografts or allografts. It also provides pull out strength measured to be greater than 1000 N, which is equivalent to or substantially higher than any of the high strength implants currently available on the market.
[0019] More particularly, a material fixation system is provided, which comprises two sheath portions defining a space therebetween, and a hinge for attaching the sheath portions together along one side thereof. An insertion member, preferably a tapered screw, is insertable into the space for expanding the sheath portions laterally outwardly in order to urge a soft tissue graft against an adjacent bone surface. In a preferred embodiment, the hinge comprises a hinge protrusion disposed on a first of the sheath portions and a hinge slot disposed on a second of the sheath portions, wherein the hinge protrusion and the hinge slot engage one another. A second hinge protrusion is disposed on the second sheath portion and a second hinge slot is disposed on the first sheath portion, wherein the second hinge protrusion and the second hinge slot also engage one another.
[0020] A driver is utilised for engaging and moving the insertion member. A hex opening is provided in the proximal end of the insertion member for engaging a distal end of the driver.
[0021] Preferably, the screw has a bullnose screw head, and the two sheath portions are mirror images of one another.
[0022] The invention is particularly advantageous, in that the system is adapted for use whether the soft tissue graft comprises an autograft, or an allograft. A distal end of the screw comprises a cut-out portion which permits the distal end of the screw to easily fit between the two sheath portions, thus permitting an operator to easily start rotation of the screw. The screw comprises external threads and the sheath portions comprise complementary internal threads. The screw further comprises a thread start to enable easier engagement of the screw threads and the sheath threads.
[0023] At least one retaining rib is preferably disposed on at least one of the sheath portions. The rib protrudes outwardly to provide a small area of higher force between the sheath portion and the soft tissue graft. The sheath portions and the insertion member are preferably adapted for insertion into a bone tunnel in a patient's tibia, and the soft tissue graft comprises a tendon graft for making an ACL repair. A cortical hook is preferably disposed on one of the sheath portions for engaging hard cortical bone at the procedural site.
[0024] One of the sheath halves preferably comprises a snap post and the other one of the sheath halves preferably comprises a complementary snap hole, wherein the snap post and the snap hole are engageable with one another to keep the two sheath halves from opening prematurely. In the preferred embodiment, a ramp is formed on one of the sheath portions for allowing a tip of the sheath portion to provide compression between the soft tissue graft and the bone at the aperture of bone tunnel in which the system is disposed. Flex grooves are disposed on one of the sheath portions, for permitting the sheath portion to flex and form around a tip of the insertion member. A bullnose sheath tip is provided on one of the sheath portions.
[0025] In some embodiments, it is advantageous for the sheath portions to further comprise a loop for retaining a soft tissue graft along a laterally outer surface of the sheath portion.
[0026] In another aspect of the invention, there is provided an implant system for promoting soft tissue to bone contact in order to promote good fixation of soft tissue to bone when making an orthopedic repair of a joint, wherein the implant system comprises a first implant adapted for receiving a tissue graft thereon and then being disposed in a first bone tunnel location, wherein ends of the tissue graft extend through a bone tunnel and out of a proximal end of the tunnel. A second implant is adapted for disposition in a second bone tunnel location, proximal to the first bone tunnel location, wherein the second implant comprises a plurality of sheaths having laterally outer surfaces and being adapted for advancing to the first bone tunnel location by sliding over the ends of the tissue graft, so that when the second implant is in the second bone tunnel location, the tissue grafts are disposed between the laterally outer surfaces of the plurality of sheaths and the bone defining the bone tunnel. An insertion member is insertable between the plurality of sheath members to laterally expand the sheath members toward the soft tissue grafts, thereby urging the soft tissue grafts into contact with the bone defining the bone tunnel.
[0027] In still another aspect of the invention, there is provided a material fixation system, which comprises a plurality of sheath portions defining a space therebetween, wherein the sheath portions are initially engaged with one another in an undeployed orientation. An insertion member is insertable into the space for expanding the sheath portions laterally outwardly to a fully deployed orientation in order to urge a soft tissue graft against an adjacent bone surface. As the sheath portions expand outwardly to the aforementioned fully deployed orientation, they become detached from one another.
[0028] In yet another aspect of the invention, there is disclosed a method of making an orthopedic repair by fixing a soft tissue graft to bone. The disclosed method comprises a step of creating a tunnel within a desired bone site, wherein the tunnel extends through a first bone member and comprises a blind hole in a second bone member. A soft tissue graft is placed on an implant. The implant is secured within the blind hole, such that a plurality of ends of the soft tissue graft extend from the implant and substantially entirely through the tunnel in the first bone member. A second implant is then slid along the soft tissue graft ends into the tunnel in the first bone member, to a predetermined location. The second implant is then expanded outwardly to compress the soft tissue graft ends against the bony wall of the bone tunnel.
[0029] The invention, together with additional features and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying illustrative drawing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] FIG. 1 is a view of the femur and tibia of a patient's leg;
[0031] FIG. 2 is a view similar to FIG. 1 , showing the use of a drill bit to make an access tunnel in the femur; and a corresponding blind hole in the tibia;
[0032] FIG. 3 is a view similar to FIGS. 1 and 2 showing the femur and tibia after the drilling step has been completed;
[0033] FIG. 4 is a view similar to FIGS. 1-3 , after a femoral anchor has been installed into the femur access hole, illustrating graft tendon bundles extend from the femoral anchor through the tibia access tunnel;
[0034] FIG. 5 is a view showing a soft tissue graft pre-loaded onto a femoral implant for use in a graft procedure performed in accordance with the principles of the present invention;
[0035] FIG. 6 is a view showing the femoral implant being inserted into the femoral socket and deployed;
[0036] FIG. 7 is a view showing the femoral implant inserted being disengaged from the deployed femoral implant;
[0037] FIG. 8 is an isometric view of an embodiment of a tibial implant constructed in accordance with the principles of the present invention;
[0038] FIG. 9 is a perspective view of a screw portion of the tibial implant of FIG. 8 ;
[0039] FIG. 10 is a cross-sectional view of the screw portion of FIG. 9 ;
[0040] FIG. 11 is a driver used to deploy the tibial implant of the present invention;
[0041] FIG. 12 is a perspective view of an assembled tibial implant according to the present invention;
[0042] FIG. 13 is a perspective view of a disassembled tibial implant according to the present invention;
[0043] FIG. 14 is a perspective view of an exterior surface of one tibial sheath which forms a part of the tibial implant of the present invention;
[0044] FIG. 15 is a perspective view of an interior surface of the sheath of FIG. 14 ;
[0045] FIG. 16 is a perspective view of an assembled tibial sheath according to the present invention, shown from a first side thereof;
[0046] FIG. 17 is a perspective view of the sheath of FIG. 16 shown from a second side thereof;
[0047] FIG. 18 is a top view of the sheath of the present invention;
[0048] FIGS. 19-21 show the undeployed tibial implant in the tibia;
[0049] FIG. 22 shows the undeployed tibial implant;
[0050] FIG. 23 shows the undeployed screw and sheath combination;
[0051] FIG. 24 shows the tibial implant as it is in the process of being deployed;
[0052] FIG. 25 shows the screw rotated to cause the sheaths to start to deploy and rotate on their hinges as shown in FIG. 24 ;
[0053] FIG. 26 shows the fully deployed tibial implant;
[0054] FIG. 27 shows the fully inserted screw, with the sheaths separated and fully deployed, as shown in FIG. 26 ;
[0055] FIG. 28 is a view showing the fully deployed implant in the tibia;
[0056] FIG. 29 is a table showing measured pull out forces for an implant of the present invention, compared with the much lower pull out forces measured in a state of the art prior art tibial implant;
[0057] FIG. 30 is a perspective view showing a modified embodiment of a sheath which forms a part of a tibial anchor device constructed in accordance with another embodiment of the present invention;
[0058] FIG. 31 is a perspective view of an anchor portion of the tibial anchor device of FIG. 30 ;
[0059] FIG. 32 is a perspective view of a screw of the tibial anchor device of FIGS. 30 and 31 ;
[0060] FIG. 33 is a perspective view of the opposing side of the sheath shown in FIG. 30 ;
[0061] FIG. 34 is a perspective view of an opposing side of the anchor portion of FIG. 31 ;
[0062] FIG. 35 is view similar to FIGS. 1-4 , with portions of the bone removed in order to show the tibial anchor device of FIGS. 30-34 , wherein the tendon bundles have been pulled through the sheaths of the anchor device;
[0063] FIG. 36 is a view similar to FIG. 35 wherein the sheaths and anchor have been slid up along the tendons into the hole until the anchor bottoms out against an angular surface within the hole;
[0064] FIG. 37 is a view similar to FIG. 36 , wherein tension has been applied to the tendons and the screw of FIG. 32 has been inserted into the anchor;
[0065] FIG. 38 is a view similar to FIG. 37 , wherein the screw has been tightened until it bottoms out against the anchor;
[0066] FIG. 39 is a view similar to FIG. 38 wherein the tendon bundles have been trimmed flush with the face of the anchor;
[0067] FIG. 40 is a view similar to FIG. 39 , except that the removed portions of the bone have been restored in order to shown the patient's knee after the inventive repair procedure has been completed;
[0068] FIG. 41 is a perspective view showing a right anchor portion of another embodiment of a tibial anchor device constructed in accordance with the principles of the present invention;
[0069] FIG. 42 is a perspective view similar to FIG. 41 showing a left anchor portion of the embodiment of the tibial anchor device of FIG. 41 ;
[0070] FIG. 43 is a view of a screw retention cup of the tibial anchor device of FIG. 41 ;
[0071] FIG. 44 is a perspective view of a screw for use with the tibial anchor device of FIG. 41 ;
[0072] FIG. 45 is a perspective view similar to FIG. 41 of the opposing side of the right anchor portion;
[0073] FIG. 46 is a perspective view similar to FIG. 42 of the opposing side of the left anchor portion;
[0074] FIG. 47 is a view similar to FIG. 43 of the opposing side of the screw retention cup;
[0075] FIG. 48 is a view of a patient's femur and tibia, with portions of the bone removed for ready visualization, showing the tibial anchor of FIGS. 41-47 being installed, by pulling tendon bundles through the left and right anchors;
[0076] FIG. 49 is a view similar to FIG. 48 , wherein the anchor portions are slid up the tendons into the bone hole until the anchor bottoms out against an angular surface in the hole;
[0077] FIG. 50 is a view similar to FIG. 49 , wherein the tendons have been tensioned, and the screw and retainer cup tightened;
[0078] FIG. 51 is a view similar to FIG. 50 , wherein the tendon bundles have been trimmed flush with the face of the anchor;
[0079] FIG. 52 is a view similar to FIG. 51 , except that the removed portions of the bone have been restored in order to shown the patient's knee after the inventive repair procedure has been completed;
[0080] FIG. 53 is a perspective view of a tibial anchor device similar to that shown in FIGS. 41-47 , in an assembled configuration;
[0081] FIG. 54 is another view of the anchor device of FIG. 53 ;
[0082] FIG. 55 is still another view of the anchor device of FIGS. 53 and 54 ;
[0083] FIG. 56 is yet another view of the anchor device of FIGS. 53-55 ;
[0084] FIG. 57 is a view of the anchor device of FIG. 54-56 , wherein some of the anchor portions have been removed for visibility;
[0085] FIG. 58 is a perspective view of yet another tibial anchor embodiment in accordance with the principles of the present invention;
[0086] FIG. 59 is another view of the embodiment of FIG. 58 ; and
[0087] FIG. 60 is still another view of the embodiment of FIGS. 58-59 .
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0088] Referring now more particularly to the drawings, procedures and anchoring devices for repairing a patient's knee, by securing a graft of soft tissue therein, connected between the patient's femur and tibia, are illustrated. There is shown in FIG. 1 a view of a femur 10 and a tibia 12 of a patient's knee. FIG. 2 illustrates the same knee structure, wherein a drill bit 14 is utilized to drill a tunnel in the tibia 12 , and a blind hole corresponding to the tunnel in the femur 10 . The tibial tunnel 16 and femur blind hole 18 are shown in FIG. 3 .
[0089] As shown in FIG. 5 , a tendon bundle 20 is pre-loaded onto a femoral implant 22 . In a preferred embodiment, the tendon bundle 20 is comprised of a soft tissue graft comprising a portion of a hamstring (such as pre-harvested semitendinosus and gracilis grafts), but any soft tissue may be used. Details of a presently preferred femoral implant are disclosed in co-pending provisional patent application Ser. No. 60/854,178, which has already been expressly incorporated herein by reference. However, the invention may be utilized with any suitable femoral implant.
[0090] In FIG. 6 , a femoral implant inserter 24 is utilized to insert the femoral implant into the femoral socket, wherein it is deployed. Following this, as shown in FIG. 7 , the femoral implant inserter 24 is disengaged from the deployed implant 22 , and withdrawn.
[0091] In FIG. 4 , the femoral anchor (not shown) has already been inserted into the femur blind hole 18 for securing the tendon bundle 20 therein, as shown. As is illustrated, the tendon bundles 20 extend from the femoral anchor in the femur hole 18 down through the tibial tunnel 16 .
[0092] Referring now to FIGS. 8-10 and 12 - 18 , there is shown a first, and presently preferred, embodiment of a tibial implant 26 constructed in accordance with the principles of the present invention. As shown in FIG. 8 , the implant 26 comprises a tapered screw 28 and two sheath portions, or halves 30 . The two sheath halves 30 are preferably mirror images of one another.
[0093] The tapered screw 28 , shown particularly in FIGS. 9 and 10 , has several key features. The tapered design, tapering from a relative wide proximal end 32 to a relatively narrow distal end 34 , distributes the pressure between the tendon and the sheath halves 30 throughout the length of the screw 28 , increasing the pull out force of the system. The screw has an easy start feature 36 , which comprises a cut-out that allows the tip of the screw to fit between the sheath halves 30 . With the tip between the sheaths, a thread start 38 ( FIG. 10 ) easily engages thread 40 on the screw with an internal thread 41 of the sheath ( FIG. 15 ) as the screw is rotated clockwise. This minimizes the force required to start the screw by reducing the distance the sheath halves 30 must be spread apart in order to start the screw. This feature also prevents the user from needing to dilate the hole between the tendon bundles. A tapered hex 42 ( FIG. 10 ) engages with a driver 44 ( FIG. 11 ) in order to transmit the torque required in order to deploy the screw. A bullnose screw head 46 at the proximal end 32 of the screw 28 leaves a smooth completed repair.
[0094] The sheath halves 30 have many key features as well. It is first noted that having two sheath halves 30 allows for the use of either a double or a single tendon bundle loop 20 . There is no need to separate four separate ends of a double tendon bundle loop into four separate quadrants. With a double bundle loop, the implant has two free ends on either side of the sheath assembly. With a single bundle loop, one free end is in place on either side of the sheath assembly. The internal thread 41 ( FIG. 15 ) on each sheath half 30 prevents the screw from backing out of the sheath assembly during and after deployment. The interlocking threads 40 , 41 between the screw and the sheaths allow the screw to be pulled between the sheath halves 30 , thus providing easier deployment. Retaining ribs 48 provide small areas of higher force between the implant and the tendon, thereby increasing the pull out force of the system.
[0095] A cortical hook 50 functions to grab the hard cortical bone of the tibia, which assists in keeping the implant in place during loading and also increases the pull out force of the system. Each sheath half 30 comprises a hinge 52 and a hinge slot 54 . The hinge 52 on one sheath half 30 is placed in the hinge slot 54 of the opposing sheath half 30 . This feature permits the sheath to consistently open up in one direction, as shown in FIGS. 22 , 24 , and 26 , thus providing a repeatable deployment mode. One sheath half 30 has two snap posts 56 , and the opposing sheath half 30 has a snap hole 58 . These features keep the sheath halves 30 from opening prematurely. A screw ramp 60 ( FIG. 18 ) allows for the tip of the sheath to provide compression between the tendon and the bone at the aperture of the tibial tunnel. A bullnose sheath tip 62 provides for a smooth transition between the implant system and the exit of the tibial tunnel. This reduces any stress concentrations that could sever the tendon bundle 20 .
[0096] Another feature that reduces stress concentrations at the tip of the sheath halves 30 are flex grooves 64 . These grooves 64 allow the sheath halves 30 to flex and form around the tip of the screw 28 .
[0097] Now with reference to FIGS. 19-28 , the deployment of the implant 26 will be described. The sheath halves 30 of the tibial implant 26 are disposed between the tendon bundles 20 in the tibial tunnel 16 , which extend proximally through the tibial tunnel 16 from the femoral implant. The sheath halves 30 are advanced distally through the tunnel 16 until the cortical hook 50 is flush with the cortical surface of the tibia. The hook is aligned to the top of the tibial tunnel. The graft is then tensioned by pulling the tendons 20 taut, using manual traction, tensioning pulleys, or other suitable means. Again, it is noted that the primary objective with respect to the tibial anchoring solution is to ensure that good aperture fixation is achieved, and to ensure that cancellous bone fixation is not entirely relied upon. Some type of cortical fixation or backup is required to ensure a good and permanent result.
[0098] The screw 28 is then placed on a distal end 66 of the hex driver 44 until it is fully seated. Next, the screw 28 is placed with the flat of the easy start feature 36 parallel with the midplane of the sheath halves 30 . With a force applied in a direction axial to the tibial tunnel, the screw is pushed distally between the sheaths. The implant 26 , in its undeployed state, is shown in FIGS. 22 and 23 .
[0099] While the axial force is being applied, and the easy start feature 36 is placed between the sheaths, the screw is rotated in a clockwise direction. This further separates the sheath halves 30 and presses the tendons 20 to the wall of the tibial tunnel 16 . The hinges 52 , 54 along the same edge as the cortical hook are used to encourage the sheath halves to open in one direction, as shown in FIGS. 24 and 25 . The screw 28 is rotated until it is fully seated when the bullnose screw head 46 is flush with the cortical surface of the tibia.
[0100] FIGS. 26 and 27 show the screw in a fully inserted state, with the sheath halves 30 separated and fully deployed. In this state, the sheath halves 30 push the tendons 20 outwardly, into contact with the tibial tunnel walls. The fully deployed implant in the tibia is shown in FIG. 28 .
[0101] As shown in FIG. 29 , verification testing of the embodiment shown in FIG. 28 was completed by the inventors, relative to a prior art device which is presently considered to be state of the art. As can be seen from the table, the pull out forces for the inventive implant were significantly higher than those for the prior art device. The average pull out force for the inventive device for bovine bone was 1165.2 N, as opposed to 532.7 N for the prior art device.
[0102] Now with reference to FIGS. 30-34 , various components of another embodiment of a tibial sheath anchor are illustrated. In FIGS. 30 and 33 , there is shown a sheath half 30 from two opposing sides thereof. An anchor 68 is shown in FIGS. 31 and 34 , and comprises a pair of legs 70 and a disk 72 . A screw 28 is provided for actuating the anchor from an undeployed to a deployed configuration for securing the anchor and associated tendon bundle in place with respect to adjacent bone.
[0103] Referring now to FIG. 35 , the patient's femur 10 and tibia 12 are shown wherein a sheath anchor 74 is assembled and disposed for insertion into the tibial tunnel 16 . In accordance with the inventive procedure, the tendon bundles 20 are pulled through the sheath halves 30 , as shown, with portions of each sheath half serving to retain the tendon bundles in place adjacent to the and along the sheaths. In particular, in the illustrated embodiment, tendon loops 76 on each sheath half 30 are formed so that the tendon bundles slide lengthwise along the sheath half 30 beneath the loops 76 so that the loops perform a retention function. The anchor 74 and its legs 70 are placed between the sheath halves 30 so that square tabs 78 on the anchor legs 70 ( FIG. 31 ) are aligned with receptacle notches 36 on the rear of the sheath half 30 ( FIG. 33 ). The screw taper on the rear of the sheath half 30 is oriented toward the joint 82 , between the femur and the tibia.
[0104] In FIG. 36 , the sheath halves 30 and anchor 68 have been slid up along the tendon bundles 20 until the anchor bottoms out against an angular surface in the hole 16 . Then, as shown in FIG. 37 , tension is applied to the tendon bundles 20 , and the screw 28 is inserted and tightened within the anchor body, using a suitable tool, such as a hex driver. As shown in FIG. 38 , the screw 28 should be tightened until it bottoms out against the anchor 68 , approximately flush with or slightly recessed relative to the entrance to the tibial tunnel 16 . This is important in order to ensure that there are no protrusions from the tunnels 16 which could cause discomfort to the patient or possible later complications and wear. An important advantage of the present invention is that the distal end 84 of the sheath anchor 30 , as shown, for example, in FIG. 38 , is disposed, once the anchor is fully inserted and deployed, so that it is in close proximity to the distal end (aperture) 86 ( FIG. 49 ) of the tibial tunnel 16 , at the joint 82 . This provides excellent aperture fixation for the tendon bundles 20 , in order to minimize wear on the tendon bundles over time due to the “windshield wiper” or “bungee” effects noted above in the Background of the Invention portion of the specification.
[0105] Deployment of the anchor 68 occurs when the screw 28 is inserted into the anchor body. This insertion action causes the anchor legs 70 to splay laterally outwardly, thus forcing the sheath halves 30 and tendon bundles 20 against the bony wall forming the tibial tunnel 16 . As a result of this action, the tendon bundles 20 are clamped against the tibial bone 12 by the sheath halves 30 .
[0106] FIGS. 39 and 40 illustrate the patient's knee joint once the inventive procedure has been completed. FIG. 39 shows the joint with portions of the bone being removed or transparent so that the entire sheath anchor 30 is visible, while FIG. 40 shows the same joint as it would appear naturally with all bone in place. The final step of the procedure is to trim the protruding ends 88 ( FIG. 38 ) of the tendon bundles 20 so that they are flush with the face of the sheath anchor 30 .
[0107] FIGS. 41-47 illustrate components of a second inventive tibial anchor embodiment, which may be identified as a “cone anchor”. FIGS. 41 and 45 illustrate opposing sides of a right anchor portion 90 and FIGS. 42 and 46 illustrate opposing sides of a left anchor portion 92 . Opposing sides of a generally conical screw retention cup 94 are shown in FIGS. 43 and 47 . A screw 28 is shown in FIG. 44 . It is noted that, in this embodiment, all like elements to those shown in previous embodiments will bear identical reference numerals.
[0108] The procedure for utilizing a cone anchor 96 of FIGS. 41-47 ( FIG. 48 ) to repair a patient's joint 82 is initiated in the same manner as for the sheath anchor 30 . Thus, as shown in FIGS. 1-4 , a femur hole 18 and tibial tunnel 16 are drilled, and a femoral anchor is inserted and deployed to anchor tendon bundles 20 in place within the femoral hole 18 , so that the tendon bundles 20 extend downwardly through the tibial tunnel 16 , as shown in FIG. 4 . The reader is referred to the description above for further detail regarding this part of the procedure.
[0109] Now, as shown in FIG. 48 , the tendon bundles 20 are pulled through the cone anchor 96 in order to insert the tibial anchor into the tibial tunnel 16 . In this embodiment, the tendon bundles are secured against the anchor portions 90 or 92 because they are pulled through tendon loops 76 , which are formed in the proximal end of each anchor half 90 , 92 , respectively. Then, as shown in FIG. 49 , the anchor 96 is slid upwardly along the tendon bundles 20 until the anchor 96 bottoms out against the angular surface in the tibial hole 16 , as with the first embodiment. Again, as in the first embodiment, this positioning will cause the distal end 98 of the anchor 96 to be located in close proximity to the distal end 86 of the tibial tunnel 16 so that good aperture fixation will result. Then, as illustrated in FIG. 50 , the tendons are appropriately tensioned and the screw 28 is inserted and tightened, together with the retainer cup 94 , until seated. This action of inserting and tightening the screw 28 and screw retainer cup 94 will cause the anchor portions 90 , 92 to move laterally outwardly in order to engage the tendon bundles 20 between the anchor portions 90 , 92 and adjacent tibial bone, as in the sheath anchor embodiment. FIGS. 51 and 52 illustrate the anchor 96 in its fully installed condition, after the tendon ends 88 are trimmed flush and the procedure is otherwise completed.
[0110] FIGS. 53-57 illustrate, in somewhat greater detail and in an assembled configuration, a cone anchor 96 of a type very similar to that illustrated in the embodiment of FIGS. 41-52 . Like elements are denoted by like reference numbers.
[0111] A modified tibial anchor embodiment 100 is illustrated in FIGS. 58-60 . This embodiment is similar to prior disclosed embodiments to the extent that there are provided two opposing sheaths having tendon loops 76 disposed thereon. A screw 28 and associated screw retention disk or cup 94 are also provided. Thus, the basic procedural steps for utilising this anchor 100 are similar to those already described in connection with the previous disclosed embodiments. What is different about this embodiment, in particular, is the provision of a distal wedge 101 which functions to provide positive aperture fixation by ensuring that the anchor will be stopped within the tibial tunnel at an appropriate point during the insertion step. Pivotable arms 102 connect the anchor body to the wedge 101 , wherein the arms 102 are pivotable outwardly about hinges 104 . Thus, when it is desired to lock the tibial anchor 100 in place within the tibial tunnel, insertion and tightening of the screw 28 within the anchor body actuates the arms 102 to pivot outwardly laterally about the hinges 104 , thereby functioning to expand the wedge and cause positive engagement of the wedge and arms 102 with the tendon bundles and adjacent tibial bone. As in prior embodiments, positive fixation is enhanced by the provision of spikes 106 or other suitable means for penetrating the tendon bundles and the bone to lock the tendon bundles and anchor in place.
[0112] Accordingly, although an exemplary embodiment of the invention has been shown and described, it is to be understood that all the terms used herein are descriptive rather than limiting, and that many changes, modifications, and substitutions may be made by one having ordinary skill in the art without departing from the spirit and scope of the invention. | A material fixation system is particularly adapted to improve the tendon-to-bone fixation of hamstring autografts, as well as other soft tissue ACL reconstruction techniques. The system is easy to use, requires no additional accessories, uses only a single drill hole, and can be implanted by one person. Additionally, it replicates the native ACL by compressing the tendons against the aperture of the tibial tunnel, which leads to a shorter graft and increased graft stiffness. It is adapted to accommodate single or double tendon bundle autografts or allografts. It also provides pull out strength measured to be greater than 1000 N. | 0 |
BACKGROUND OF THE INVENTION
[0001] The present invention relates to steam irons in which steam is produced in a quasi-instantaneous manner. These appliances have a useful life that is limited by the build up of scale in the steam chamber.
[0002] Numerous devices for reducing the occurrence of scale in an iron have been proposed. One of the most successful physical-chemical systems diffuses a phosphorated product into water before the water is vaporized in order to impede crystallization of the scale in a hard form and to permit its removal by the steam flow. French patent FR 2 757 364 describes an embodiment of such a device where the diffusion of sodium hexametaphosphate (SHMP), which is highly soluble, is controlled by a silicone matrix placed in the water circuit. However, it has been noted that the scale that is formed tends to partially agglomerate under the action of the steam and detaches in the form of flakes that are friable but that are evacuated in bunches that stain the fabric being ironed.
[0003] The particles can be retained in the steam chamber by a metal screen as suggested in the German patent DE 3006783 or the Japanese patent 60160999. A screening can equally be produced in a manner disclosed in the French patent FR 2 696 197 where a grid intended to improve the vaporization has its edges raised in the form of bowl. However, the utilization of a screening grid alone eventually provokes blockages of the steam chamber by very hard scale, which cannot be evacuated.
BRIEF SUMMARY OF THE INVENTION
[0004] The present invention has as an object a scale reducing device that will prolong the useful life of a steam iron while permitting regular evacuation of scale in a powder form powder that is invisible to the user and will not stain articles being ironed, while preventing obstruction of the chamber as well as of the steam vaporization channels, including the steam delivery holes in the iron soleplate.
[0005] The above and other objects are achieved, according to the invention, by a steam iron composed of: a metal heating body containing a chamber that has a steam generating zone; means defining a water flow path in communication with the chamber, the water flow path including a compartment containing a quantity of a scale reducing agent that is contacted by water flowing along the path before the water reaches the chamber, the scale reducing agent being obtained by cross-linking or hardening a silicone elastomer of an organosilicic system that is permeable to water vapor and having an active hydrophilic material and a polyorganosiloxane composition; and a screen made of a metal different from that of the heating body and disposed in proximity to the steam generating zone at a location to be traversed by steam generated in the steam generating zone.
[0006] The scale reducing agent could be fabricated in the manner disclosed in French patent FR 2 757 364.
[0007] Preferably, the active hydrophilic material is selected from among the metaphosphates of sodium or of potassium. It has been found that in the case of steam irons according to the present invention, no visible flakes exit through the steam delivery holes of the soleplate even when the screen has holes with a hydraulic diameter of the order of two millimeters. Surprisingly, scale does not accumulate in the steam chamber, or in the steam flow channels.
[0008] Preferably, the screen is fitted, or gripped, or clamped, tightly between two walls of the steam chamber of the pressing iron.
[0009] The process that permits the scale to be present in the form of a very fine powder that is not visible at the outlet of the iron is not clearly understood. Possibly, the friable flakes that detach from the steam generating zone are retained and rub against the screen, which breaks them into the very fine particles. Possibly, the scale that is deposited on or against the screen is broken up by thermal expansion and contraction of the screen. It is also possible that there is an unknown phenomenon resulting from the difference in electrical potential caused by the different characteristics of the metal making up the heating body and the different metal of the screen. This difference in electric potential could have an effect due to the good electric connection resulting from the tight gripping of the screen in the heating body.
[0010] Preferably, the screen is coated with a gold layer. This layer protects the screen and prevents it from rusting or corroding. It is also noted that the gold gives rise to a large electric potential difference with a heating body made of aluminum. According to another possibility, the screen can be made of stainless steal.
[0011] In either case, the screen is protected from oxidation phenomena and the appearance of a potential difference with a heating body of aluminum is promoted.
[0012] Also preferably, the screen is made of an expanded metal that is better able to break up the scale which comes to deposited on or against the screen.
[0013] Preferably, the scale reducing agent is contained in a tube and librates its active ingredients through at least one open end of the tube.
[0014] The silicone can be in form of matrix molded into the tube without requiring another mold. The active material is librated with a kinetic of the order of unity. This means that the active material is librated at a substantially rate, at least when the temperature of the matrix remains substantially constant. The active material is librated through a progressive front of cracks in the matrix, which coincides with the cross section of the tube so that the liberation of active material is thus perfectly controlled.
[0015] Preferably, the tube containing the scale reducing agent is placed in the water reservoir of the iron. The scale reducing agent can be present in a quantity sufficient to assure a good functioning of the system during the entire expected useful life of the iron, or can be renewable. Placement in the water reservoir is simplified when the matrix is molded within the tube.
BRIEF DESCRIPTION OF THE DRAWING
[0016] [0016]FIG. 1 is a simplified side cross-sectional view, along line I-I of FIG. 2, of a pressing iron constructed according to the present invention.
[0017] [0017]FIG. 2 is a plan view of the soleplate of the iron shown in FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
[0018] A preferred embodiment of a steam pressing iron according to the invention is shown in FIGS. 1 and 2. This iron is composed of a soleplate 1 having a steam generating chamber 2 , a water reservoir 3 , a droplet delivery system 4 permitting water to be supplied at a desired rate to chamber 2 from reservoir 3 , and a housing, or casing, 5 that includes a handle for grasping the iron.
[0019] Reservoir 3 is formed by two pieces 300 and 301 and has a filling opening 302 that can be closed by a sliding cover 303 . A tubular element 304 having a constant cross-section perpendicular to the plane of FIG. 1 is disposed at the interior of reservoir 3 . Element 304 is filled with a molded silicone elastomer matrix 305 containing SHMP in the form of a solid dispersion. One or both ends of element 304 , which ends are parallel to the plane of FIG. 1, are open to expose matrix 305 to water within reservoir 3 . Element 304 is installed to be in contact with water in reservoir 3 .
[0020] Soleplate 1 contains a heating body 100 made of aluminum and defining the walls of steam generating chamber 2 . Soleplate 1 further has a tubular resistive heating element 101 , a closing plate 102 and a cap, or liner, 103 that is in thermal communication with heating body 100 . Closing plate 102 constitutes the upper wall, or cover, of chamber 2 . Liner 103 constitutes the external ironing surface of the iron and is intended to be in contact with articles that are being ironed.
[0021] Chamber 2 has a zone 200 , shown most clearly in FIG. 2, into which water drops are delivered from system 4 . Zone 200 , in which steam is produced, is extended across soleplate 1 by a second zone 201 that is closed by ribs 202 and a screen 203 . Screen 203 is an element preferably made of an expanded metal, such as stainless steel, optionally plated with a thin layer of gold. Screen 203 is tightly clamped between closing plate 102 and the bottom of chamber 2 in order to assure an excellent electric contact between plate 102 , screen 203 and heating body 100 . An electric potential difference is established between screen 203 and heating body 100 as a consequence of the different characteristics of the two different metals employed for screen 203 and heating body 100 .
[0022] Screen 203 is formed to have a mesh width between 0.3 and 3 millimeters and is made up of wires preferably having a polygonal cross-section, which may for example be triangular, square, or rectangular. Screen 203 is made of a metal material different from that of heating body 100 and/or plate 102 , and may for example be made of stainless steel, optionally covered with a gold layer having a thickness between 10 μm and 100 μm.
[0023] Advantageously, the bottom of chamber 2 is covered with an anti-calefaction coating, i.e. a coating that prevents water droplets dropped onto a hot plate from remaining in liquid form. The steam produced in chamber 2 can escape through passages 206 , channels 204 and holes 207 toward steam delivery openings 205 that are provide in liner 103 for delivery to an article being pressed, either directly or via other distribution channels located the soleplate. The steam delivery passages and channels and the steam outlet openings in liner 103 can be formed according to principles that are well known in the art.
[0024] When the pressing iron is at room temperature, only very little SHMP is librated from silicone matrix 305 , even if matrix 305 is wetted. When the iron is to be used, the user fills water reservoir 3 via opening 302 and then moves cover 303 into the closed position shown in FIG. 1. When the iron is heated, the temperature in the reservoir is first raised to a moderate level that is sufficient to strongly accelerate diffusion of SHMP into the water, and vapor diffusing toward the SHMP grains, which are very hydrophilic, causes the grains to be charged with water and to swell, thereby breaking the silicone network. The SHMP diffusion front progresses slowly into the matrix along the axis of tubular element 304 , i.e. perpendicular to the plane of FIG. 1, the cross-section of element 304 being constant in this direction, and the diffusion of SHMP is thus well controlled.
[0025] Preferably, the length and cross-section of tubular element 304 are selected to assure a continued diffusion of the scale-preventing product for the useful life of the iron. In another form of construction, tubular element 304 and its silicone matrix 305 are replaceable.
[0026] During ironing, the user can activate a control element 40 to operate system 4 , leading to the production of steam that will be used in the ironing process. When control element, or button, 40 is depressed, water containing dissolved SHMP is allowed to flow in the form of drops from reservoir 3 into chamber 2 , where the drops fall into zone 200 . The water spreads out to a greater or lesser extent across chamber 2 , the extent depending on the flow rate, and reaches zone 201 . Vaporization of the water produces steam which flows toward the article being ironed while passing through screen 203 and then into passages 206 and channels such as 204 and holes 207 in order to reach delivery of openings 205 of the soleplate.
[0027] Any scale left by the vaporization of the water is in large measure in powder form due the action of the SHMP and is evacuated by being at least in part entrained by the steam.
[0028] Another part of the scale left by the water attaches to the wall of chamber 2 in the form of a crumbly, or friable, layer, which scale material subsequently detaches in the form of flakes that are then retained by screen 203 . A further part of the scale comes to be deposited as a crust directly on screen 203 . Surprisingly, the flakes and the crust of scale disintegrate at the level of the screen into a fine powder that is invisible to the naked eye, this powder then being evacuated out of the iron through the steam delivery openings. It is thought that the electric potential differential present at the level of screen 203 , of the order 2-3 volts, provokes a transformation of the cohesion of the scale crystals, this transformation possibly being completed by the polygonal geometry of the cross-section of the wires of the screen. Screen 203 then is able to prevent the passage of large particles and retains them so that they can be transformed into fine powder. According to other embodiments of the invention, the SHMP can be replaced another hydrophilic phosphorous product.
[0029] As a result, the scale is evacuated regularly in an invisible form and without inconveniencing the user. The useful life of the iron is increased by the hydrophilic scale-preventing product while, at the same time, this product does not create any inconveniences, such as the appearance of stains on the articles being ironed.
[0030] This application relates to subject matter disclosed in German Application No. DE-100 14 815.8, filed Mar. 27, 2000, the entirety of which is incorporated herein by reference.
[0031] The foregoing description of the specific embodiments will so fully reveal the general nature of the invention that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without undue experimentation and without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. The means, materials, and steps for carrying out various disclosed functions may take a variety of alternative forms without departing from the invention. Thus the expressions “means to . . . ” and “means for . . . ”, or any method step language, as may be found in the specification above and/or in the claims below, followed by a functional statement, are intended to define and cover whatever structural, physical, chemical or electrical element or structure, or whatever method step, which may now or in the future exist which carries out the recited function, whether or not precisely equivalent to the embodiment or embodiments disclosed in the specification above, i.e., other means or steps for carrying out the same functions can be used; and it is intended that such expressions be given their broadest interpretation. | A steam iron composed of: a metal heating body containing a chamber that has a steam generating zone; a water flow path in communication with the chamber, the water flow path including a compartment containing a quantity of a scale reducing agent that is contacted by water flowing along the path before the water reaches the chamber; and a screen made of a metal different from that of the heating body and disposed in proximity to the steam generating zone at a location to be traversed by steam generated in the steam generating zone. | 3 |
TECHNICAL FIELD
[0001] The present invention relates to a method for weaving multiply gauze and a multiply gauze woven fabric woven by the method.
BACKGROUND ART
[0002] A gauze woven fabric is a plain-woven fabric roughly woven by using a relatively thin thread. The gauze woven fabric is characterized by lightweight and breathability.
[0003] When the gauze woven fabric is applied to cloth for clothes and bedding by utilizing the characteristics thereof, there is still room for improvement in transparency preventing property, heat-retaining property, water absorbency, and softness.
[0004] Transparency preventing property will be improved if two or more sheets of gauze are combined to form a multiply woven fabric. On the other hand, heat-retaining property and water absorbency will be improved because of the layered structure. A remarkable improvement, however, cannot be expected. Even with the structure, softness will not be improved at all.
[0005] By the way, a towel woven gauze (a gauze woven towel or a pile gauze) can be exemplified as a gauze woven fabric that is excellent in transparency preventing property, heat-retaining property, water absorbency, and softness (Patent Literature 1).
CITATION LIST
Patent Literature
[0006] Patent Literature 1
[0007] JP 2000-220058A
SUMMARRY OF INVENTION
[0008] A towel woven gauze has both a strong point of gauze and a strong point of towel, which, however, is heavyish when applied to cloth for clothes and bedding because it requires piles. In other words, lightweight and breathability which are characteristics of gauze woven fabric cannot be sufficiently utilized.
[0009] In order to solve the above problem, the present invention provides a gauze woven fabric excellent in transparency preventing property, heat-retaining property, water absorbency, and comfort for skin (softness) while retaining lightweight and breathability.
Technical Problem
Solution To Problem
[0010] The invention capable of solving the above problem is a method for weaving a multiply gauze including
[0011] feeding warps from a first beam to form a tight layer A, and
[0012] concurrently feeding warps from a second beam having a feeding speed higher than that of the first beam to form a loosened layer B in comparison with the tensile strength of the warps of the layer A, and
[0013] forming connection parts connecting the layer A to the layer B.
[0014] In the above described invention, preferably, the feeding speed of the second beam is 0.5 to 5.0% higher than the feeding speed of the first beam.
[0015] In the above described invention, preferably, the multiply gauze is composed of a plurality of layers including a surface layer, an intermediate layer, and a back layer,
[0016] wherein the layer A is formed as the intermediate layer, and
[0017] wherein the layer B is formed as the surface layer and the back layer.
[0018] In the above described invention, more preferably,
[0019] the connection parts include first connection parts connecting the surface layer to the intermediate layer regularly and second connection parts connecting the back layer to the intermediate layer regularly,
[0020] wherein each first connection part is formed at a position corresponding to a middle position between the neighboring two second connection parts.
[0021] In the above described invention, further preferably,
[0022] the connection parts include first connection parts connecting the surface layer to the intermediate layer regularly and second connection parts connecting the back layer to the intermediate layer regularly,
[0023] wherein first connection parts are formed at positions corresponding to positons of the second connection parts.
[0024] The invention capable of solving the above problem is a multiply gauze woven fabric including
[0025] a layer A formed by strongly stretching warps fed from a first beam,
[0026] a layer B formed by loosely stretching warps than the layer A, the warps being fed from a second beam having a feeding speed higher than that of the first beam, and
[0027] connection parts connecting the layer A to the layer B.
[0028] The invention capable of solving the above problem is clothes formed by using the multiply gauze woven fabric.
[0029] The invention capable of solving the above problem is bedding formed by using the multiply gauze woven fabric.
Advantageous Effect Of Invention
[0030] The multiply gauze woven fabric of the present invention is excellent in transparency preventing property, heat-retaining property, water absorbency, breathability, and comfort for skin (softness) in comparison with the conventional multiply gauze woven fabric.
[0031] The multiply gauze woven fabric of the present invention retains lightweight of the conventional multiply gauze woven fabric.
[0032] In view of the above, the multiply gauze woven fabric of the present invention is suitable to be applied to cloth for clothes or bedding.
BRIEF DESCRIPTION OF DRAWINGS
[0033] FIG. 1 is a cross sectional view of a two-ply gauze woven fabric according to a first embodiment of the present invention.
[0034] FIG. 2 is a cross sectional view of a two-ply gauze woven fabric produced by the conventional technology.
[0035] FIG. 3 is a cross sectional view of a three-ply gauze woven fabric according to a second embodiment of the present invention.
[0036] FIG. 4 is a cross sectional view of a three-ply gauze woven fabric according to a third embodiment of the present invention.
DESCRIPTION OF EMBODIMENTS
First Embodiment
[0037] —Gauze Structure and Weaving Method—
[0038] FIG. 1 is a cross sectional view of a multiply gauze woven fabric according to a first embodiment of the present invention. The present invention is directed to a N (N is an integer 2 or greater)-ply gauze woven fabric. Here, in order to facilitate understanding of the invention, a two-ply gauze woven fabric will be exemplified.
[0039] A two-ply gauze woven fabric is equipped with a surface-layer gauze and a back-layer gauze.
[0040] The surface-layer gauze is formed of warps (lengthwise yarns) 1 , 2 and wefts (crosswise yarns) 3 , 4 .
[0041] Warps 1 , 2 for surface-layer is fed from a first beam. A warp feeding speed of the first beam is almost equivalent to a feeding speed employed in a typical gauze weaving.
[0042] At the time, a tensile strength of warps 1 , 2 is also adjusted according to the warp feeding speed.
[0043] Wefts 3 , 4 are drawn across the warps during the feeding of warps. Accordingly, a tight layer A (a typical gauze) is formed.
[0044] A back layer gauze is formed of warps (lengthwise yams) 5 , 6 and wefts (crosswise yarns) 7 , 8 .
[0045] Warps 5 , 6 for the back layer are fed from a second beam. A feeding speed of the second beam is 0.5 to 5.0%, preferably 1.5 to 3.0%, higher than the feeding speed of the first beam.
[0046] At the time, a tensile strength of warps 5 , 6 is adjusted to less than 0.8-times, preferably less than 0.6-times, of the tensile strength of warps 1 , 2 .
[0047] Wefts 7 , 8 are drawn across the warps during the feeding of warps. Accordingly, a loosened layer B in comparison with the tensile strength of the warps of the layer A is formed.
[0048] The same number of wefts 3 , 4 and wefts 7 , 8 are drawn across the warps equally spaced.
[0049] Because the feeding speed of the second beam is higher than the feeding speed of the first beam, a length of warps 5 , 6 becomes longer than a length of warps 1 , 2 . On the other hand, the layer A and the layer B have the same length in a warp direction. As a result, the layer B is loosened than the layer A.
[0050] Concurrently with the forming of the layer A and the layer B, the layer A and the layer B are connected with each other in an appropriate way. The connection parts may be formed by warps or by wefts. According to an example in the drawing, warp 2 and weft 8 are entwined with each other and, concurrently, warp 5 and weft 4 are entwined with each other, thereby forming a connection part 10 .
[0051] —Effect—
[0052] FIG. 2 illustrates a two-ply gauze woven fabric (conventional technology) composed of two sheets of typical gauze combined together. An effect of the present embodiment will be described below by comparing to the conventional technology.
[0053] Improvement of Transparency Preventing Property, Heat-Retaining Property, Water Absorbency, and Breathability
[0054] In the conventional technology, warps for a surface-layer and warps for a back layer are fed from the same beam. Therefore, the warps for both of the surface-layer and the back layer are fed at same feeding speed. As a result thereof, a flat two-ply gauze is formed. There is no space formed between two sheets of gauze. Transparency preventing property, heat-retaining property, and water absorbency improve because the two sheets of gauze are combined. The improvement, however, is not remarkable. Breathability degrades because of the two-ply structure.
[0055] To the contrary, in the first embodiment, the loosened layer B creates a space between two sheets of gauze. With two sheets of thin gauze, the resulting two-ply gauze can have a thickness. Owing to the space and the thickness, transparency preventing property, heat-retaining property, water absorbency, and breathability can be improved in comparison with the gauze fabric produced by the conventional technology.
[0056] In view of the above, the gauze fabric according to the first embodiment is suitable for cloth to be applied to clothes (gowns, pajamas, shirts, pants, articles for infants, etc.) and bedding (sheets, blankets, pillow covers, etc.).
[0057] For example, breathability works during hot summer and heat retaining property works during cold winter. Users can feel coolness in summer and warmness in winter.
[0058] Further, when the gauze fabric according to the first embodiment is used for pajamas or sheets, the space absorbs night sweats as well as breathability works to dissipate excessive body temperature while sleeping. When the air temperature is going down at dawn, the heat-retaining property works. That is, the gauze fabric according to the first embodiment can keep comfortability throughout while sleeping.
[0059] Improvement of Comfort for Skin
[0060] In the conventional technology, produced is a flat two-ply gauze and thus, when the gauze is applied to clothes or bedding, the cloth clings to a person's skin when he sweats. Further, such gauze has no bounce and is stiffness feeling.
[0061] To the contrary, in the first embodiment, a combination of the loosened layer B and the connection parts 10 generates concave/convex. When the convex portions contact skin, suitable bounce works. Therefore, a user can feel softness. More specifically, because only convex portions touch the skin (because convex portions reduce the contact area), stickiness can be reduced when sweating. As described above, feeling of comfort for skin can be improved more than that of the conventional technology.
[0062] Incidentally, upon shrinkage, wefts are bound at connection parts 10 . This makes the shrinkage in a weft direction be changed. More specifically, wefts shrink less in areas before and after the connection parts 10 , whereas, shrink more in the middle area of two neighboring connection parts 10 . This generates concave/convex also in a weft direction and thus the feeling of comfort for skin improves more.
[0063] Retaining of Lightweight
[0064] The first embodiment and the conventional technology are different from each other only in the point of warps 5 , 6 for back layer but are common to each other in surface-layer and wefts. A ratio of warps 5 , 6 of the two-ply gauze is 25% (=¼).
[0065] If the feeding speed of the second beam is 5.0% higher (i.e., longer yarn=heavier yarn) than the feeding speed of the first beam, the gauze fabric according to the first embodiment comes to be 1.25% (=25%×5%) heavier than the gauze fabric produced by the conventional technology.
[0066] Only with such increase in weight, users would not notice about the difference of weight when two-ply gauze woven fabric is applied to clothes or bedding. In other words, lightweight of gauze woven fabric can be kept.
Second Embodiment
[0067] —Gauze Structure and Weaving Method—
[0068] FIG. 3 is a cross sectional view of a three-ply gauze woven fabric according to a second embodiment of the present invention.
[0069] A three-ply gauze woven fabric is equipped with a surface-layer gauze, an intermediate layer gauze, and a back-layer gauze.
[0070] Warps are fed from a first beam and wefts are drawn across the warps, thereby forming a tight layer A as the intermediate layer gauze.
[0071] Warps are fed from a second beam and wefts are drawn across the warps, thereby forming a loosened layer B 1 as the surface-layer gauze and concurrently forming a loosened layer B 2 as the back-layer gauze.
[0072] At the time, a feeding speed of the second beam is higher than a feeding speed of the first beam.
[0073] Concurrently with forming of the layer A and forming of the layer B 1 and the layer B 2 , connection parts 11 connecting the layer A to the layer B 1 regularly and connection parts 12 connecting the layer A to the layer B 2 regularly are formed. The connection parts 11 and the connection parts 12 are formed at same intervals.
[0074] Each connection part 11 is formed at a position corresponding to a position in the middle of the neighboring two connection parts 12 . Further, each connection part 12 is formed at a position corresponding to a position in the middle of the neighboring two connection parts 11 . As a result, the surface-layer gauze and the back-layer gauze are placed in parallel with each other.
[0075] —Effect—
[0076] The second embodiment is a modification of the first embodiment. More specifically, the layer B is provided on both sides of the layer A. Therefore, the second embodiment produces an effect equivalent to the effect produced by the first embodiment. Specially, transparency preventing property, heat-retaining property, and water absorbency improve more.
[0077] A thickness formed between the surface-layer gauze and the back-layer gauze of the three-ply gauze woven fabric is even in a warp direction, and thus transparency preventing property, heat-retaining property, water absorbency, and breathability work evenly in the warp direction. As a result, users will not have unnatural feeling.
[0078] Further, the three-ply gauze woven fabric has a gentle wavy appearance.
Third Embodiment
[0079] —Gauze Structure and Weaving Method—
[0080] FIG. 4 is a cross sectional view of the three-ply gauze woven fabric according to a third embodiment of the present invention.
[0081] The three-ply gauze woven fabric of the third embodiment is common with that of the second embodiment in that the fabric is equipped with a surface-layer gauze, an intermediate layer gauze, and a back-layer gauze, in that a layer B (a layer B 1 and a layer B 2 ) is provided on both sides of a layer A, and in that connection parts 11 and connection parts 12 are formed.
[0082] On the other hand, the connection parts 11 are formed at positions corresponding to positions of the connection parts 12 in the third embodiment. Further, the connection parts 12 are formed at positions corresponding to positions of the connection parts 11 . As a result, the surface-layer gauze and the back-layer gauze are placed to be approximately linearly symmetrical with the intermediate layer gauze.
[0083] Incidentally, “positions corresponding to” has a broad concept. It means that positions up to positions of the neighboring three wefts counted from original positions of connection parts are included. In the drawing, the connection parts 11 are positioned two wefts away from the corresponding connection parts 12 .
[0084] When the connection parts 11 and the connection parts 12 are formed correspondingly at same positions, it is seen as if there are holes at the positions in appearance. If it is not preferred, the connection parts 11 and the connection parts 12 are to be positioned away from one another by 1 to 3 wefts.
[0085] —Effect—
[0086] The third embodiment is also a modification of the first embodiment as it is the case of the second embodiment. Therefore, the third embodiment produces an effect equivalent to that produced by the first embodiment.
[0087] Specially, a thickness formed between the surface-layer gauze and the back-layer gauze of the three-ply gauze woven fabric becomes thicker than that of the second embodiment. This improves transparency preventing property, heat-retaining property, and water absorbency more.
[0088] Further, the three-ply gauze woven fabric is formed into an appearance having sharp concave/convex shape. As described above, a design of appearance can be selected as required.
[0089] <Others>
[0090] Hereinabove, more specific embodiment has been described. The present invention is not limited only to the above described embodiments. In so far as the characteristics of the present invention are not impaired largely, various changes and modifications to the present invention should be construed as being included in the scope of the present invention.
[0091] For example, in the second embodiment and the third embodiment, it is possible to form the intermediate layer by combining two layers A, thereby forming a four-ply gauze woven fabric.
[0092] In the first to third embodiments, the connection parts are formed regularly but may be formed irregularly.
[0093] <Supplementary Note>
[0094] One of points of the present invention is that a multiply gauze is formed bulkily. The inventor of the present invention also studied about such a modification that the conventional multiply gauze is subjected to drying shrinkage to make it bulky.
[0095] If the multiply gauze is subjected to drying shrinkage to make it bulky, a weight per unit area increases. As a result, lightweight and breathability which are characteristics of gauze woven fabric cannot sufficiently be utilized.
[0096] Further, uneven shrinkage caused by the drying shrinkage invites poor appearance and makes cutting or sewing difficult. More specifically, such gauze woven fabric is not suitable for cloth in the use of clothes or bedding.
[0097] Therefore, it was necessary to study other method for making the multiply gauze bulky.
[0098] Incidentally, in the conventional method for weaving multiply gauze, a plurality of warps is apportioned from the same beam. It is theoretically possible to perform weaving by using two or more beams, which, however, degrades productivity. In view of the above, from the practical view point, such a concept that a plurality of beams is used in weaving gauze fabric is not conceivable by a person skilled in the art.
[0099] The inventor of the present invention came to have an idea of using two or more beams in the process of a study of making the multiply gauze bulky while retaining lightweight/breathability. The invention of the present application was made as a result of repeating trial and error as described above.
REFERENCE CHARACTER LIST
[0100] 1 , 2 warps of layer A
[0101] 3 , 4 wefts of layer A
[0102] 5 , 6 warps of layer B
[0103] 7 , 8 wefts of layer B
[0104] 10 , 11 , 12 connection parts
[0105] Layer A tight layer formed by strongly stretching warps
[0106] Layer B loosened layer formed by loosely stretching warps | To provide a gauze woven fabric which has excellent opaqueness, moisture retention properties, water absorbency and comfort for skin (softness) while maintaining light weight and air permeability which are characteristic properties of gauze woven fabrics. Warps ( 1,2 ) are supplied from a first beam, and wefts ( 3,4 ) are then drawn across the warps to form a tight layer A. Warps ( 5,6 ) are supplied from a second beam that has a higher supply speed than that of the first beam, and wefts ( 7,8 ) are then drawn across the warps to form a loosened layer B. Subsequently, knotting points for connecting the layer A to the layer B regularly are formed. | 3 |
BACKGROUND OF THE INVENTION
[0001] Many emerging applications require physical security as well as conventional security against software attacks. For example, in Digital Rights Management (DRM), the owner of a computer system is motivated to break the system security to make illegal copies of protected digital content.
[0002] Similarly, mobile agent applications require that sensitive electronic transactions be performed on untrusted hosts. The hosts may be under the control of an adversary who is financially motivated to break the system and alter the behavior of a mobile agent. Therefore, physical security is essential for enabling many applications in the Internet era.
[0003] Conventional approaches to build physically secure systems are based on building processing systems containing processor and memory elements in a private and tamper-proof environment that is typically implemented using active intrusion detectors. Providing high-grade tamper resistance can be quite expensive. Moreover, the applications of these systems are limited to performing a small number of security critical operations because system computation power is limited by the components that can be enclosed in a small tamper-proof package. In addition, these processors are not flexible, e.g., their memory or I/O subsystems cannot be upgraded easily.
[0004] Just requiring tamper-resistance for a single processor chip would significantly enhance the amount of secure computing power, making possible applications with heavier computation requirements. Secure processors have been recently proposed, where only a single processor chip is trusted and the operations of all other components including off-chip memory are verified by the processor.
[0005] To enable single-chip secure processors, two main primitives, which prevent an attacker from tampering with the off-chip untrusted memory, have to be developed: memory integrity verification and encryption. Integrity verification checks if an adversary changes a running program's state. If any corruption is detected, then the processor aborts the tasks that were tampered with to avoid producing incorrect results. Encryption ensures the privacy of data stored in the off-chip memory.
[0006] To be worthwhile, the verification and encryption schemes must not impose too great a performance penalty on the computation.
[0007] Given off-chip memory integrity verification, secure processors can provide tamper-evident (TE) environments where software processes can run in an authenticated environment, such that any physical tampering or software tampering by an adversary is guaranteed to be detected. TE environments enable applications such as certified execution and commercial grid computing, where computation power can be sold with the guarantee of a compute environment that processes data correctly. The performance overhead of the TE processing largely depends on the performance of the integrity verification.
[0008] With both integrity verification and encryption, secure processors can provide private and authenticated tamper resistant (PTR) environments where, additionally, an adversary is unable to obtain any information about software and data within the environment by tampering with, or otherwise observing, system operation. PTR environments can enable Trusted Third Party computation, secure mobile agents, and Digital Rights Management (DRM) applications.
[0000]
ACRONYMS, ABBREVIATIONS AND DEFINITIONS
Acronym
Definition
OTFA EMIF4D
On The Fly AES EMIF
MAC
Message Authentication Code
GCM
Galois/Counter Mode
CCM
CBC-MAC + CTR
GHASH
Galois HASH
CBC-MAC
AES cipher-block chaining Message
Authentication Code
AES
Advanced Encryption Standard
CTR
AES counter mode
ECB
AES electronic codebook mode
CBC
AES cipher-block chaining mode
SUMMARY OF THE INVENTION
[0009] An on the fly encryption engine is shown that is operable to encrypt data being written to a multi segment external memory, and is also operable to decrypt data being read from encrypted segments of the external memory. In order to improve memory efficiency, memory systems may return data out of order from the read requests. In order to improve the throughput of cryptographic operations, the operation may be started in a speculative manner when the read command is sent to the memory, but before the read data arrives. In order to accommodate speculative cryptographic operations, the results of the operation must be cached and then matched to the memory data when it arrives.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] These and other aspects of this invention are illustrated in the drawings, in which:
[0011] FIG. 1 shows a block diagram of the invention.
[0012] FIG. 2 is a high level flow chart of the AES encryption standard,
[0013] FIG. 3 shows a high level block diagram of the on-the-fly encryption system,
[0014] FIG. 4 shows a block diagram of AES mode 0 processing, and
[0015] FIG. 5 is a block diagram of AES mode 1 processing.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0016] FIG. 1 shows the high level architecture of this invention. Block 101 is the on the fly encryption engine positioned between processor busses 103 and 14 , and is connected to external memory interface 106 via bus 105 . configuration data is loaded into configuration register 102 via bus 103 , and unencrypted data is written/read to 101 via bus 104 . Encrypted data is communicated to/from the External Memory Interface 106 via bus 105 . External memory 107 is connected to and is controlled by 106 . External memory 107 may be comprised of multiple memory segments. These segments may be unencrypted or encrypted, and the segments may be encrypted with distinct and different encryption keys.
[0017] While there is no restriction on the method of encryption employed, the implementation described here is based on the Advanced Encryption Standard (AES).
[0018] AES is a block cipher with a block length of 128 bits. Three different key lengths are allowed by the standard: 128, 192 or 256 bits. Encryption consists of 10 rounds of processing for 128 bit keys, 12 rounds for 192 bit keys and 14 rounds for 256 bit keys.
[0019] Each round of processing includes one single-byte based substitution step, a row-wise permutation step, a column-wise mixing step, and the addition of the round key. The order in which these four steps are executed is different for encryption and decryption.
[0020] The round keys are generated by an expansion of the key into a key schedule consisting of 44 4-byte words.
[0021] FIG. 2 shows the overall structure of AES using 128 bit keys. The round keys are generated in key scheduler 210 . During encryption, 128 bit plain text block 201 is provided to block 202 where the first round key is added to plaintext block 201 . The output of 201 is provided to block 203 where the first round is computed, followed by rounds 2 through round 10 in block 204 . The output of block 204 is the resultant 128 bit cipher text block.
[0022] During decryption the 128 bit cipher text block 206 is provided to 207 , where it is added to the last round key—the round key used by round 10 during encryption. This operation is followed by computing rounds 1 through 10 using the appropriate round keys in reverse order than their use during encryption. The output of 208 , round 10 is the 128 bit plain text block 209 .
[0023] FIG. 3 is a high level block diagram of the on the fly encryption/decryption function. Plaintext to be encrypted during memory write operations is provided on data bus 305 , with decrypted plaintext output on the same bus 305 during memory reads. Configuration data is provided on bus 306 . Encrypted data bus 307 interfaces to the external memory controller.
[0024] Configuration data is input from bus 306 to the configuration block 301 . AES core block 302 contains 12 AES cores and 6 GMAC cores which perform the cryptographic work.
[0025] This block performs the appropriate AES/GMAC/CBC-MAC operation defined by the scheduler.
[0026] Half of the AES and GMAC cores are assigned to RD path and the other half to the WRT path.
[0027] Since GMAC cores operate twice has fast as the AES cores, therefore half as many are required.
[0028] The AES operations have 2 modes of operations called AES CTR and ECB+.
[0029] AES CTR is optimized for write once and read <n> times per unique Key update.
[0030] ECB+ is optimized for write <n> and read <n> times per unique Key update.
[0031] Command Buffer Block 303 tracks and stores all active transactions by accepting new transactions submitted on the data bus 305 . It tracks the External Memory Interface (EMIF) responses to the submitted commands to the EMIF. With this information OTFA_EMIF has the ability to determine which command is associated with the EMIF response. This is required to determine which command and address is associated with the read data the EMIF is presenting.
[0032] Scheduler block 304 is the main control block which controls
[0033] Data path routing
[0034] AES/MAC operations
[0035] Read/Modify/write operations
[0036] Data path routing is simple routing of the data sources for the AES operation. There are 2 possible data sources, the input write data and EMIF read data. Read data is required for read transactions or write transactions that require an internal read modify write operation.
[0037] The scheduler block will issue an internal Read Modify Write operation during the following conditions:
[0038] During ECB+ write operation when any of the byte enables are not active for each 16 Byte transfer;
[0039] During write operation when MAC is enabled and the block being written is not a complete 32 Byte transfer. The scheduler block will issue a modified Read command when accessing a MAC enabled region when the Read command is not a multiple of 32 Bytes. These operations are shown in Table 1.
[0000]
TABLE 1
System
Transaction
Action
Write using
On this first detection of a missing byte
ECB+ mode and
enable, OTFA will nullify all byte enables
not all 16 Bytes
for the complete transaction, mask the emif
are enabled
response, issue a Read cmd to build the
complete block, then create a new write
data block and issue a new write command,
the response of this new command will cause
a response of the original write command
Write using MAC
Same as above
modes and not
all 32 Bytes are
enabled
Read using MAC
The Read operation will get extend to align
modes and size
to 32 Bytes.
is not in
The system response will appear to be the
multiplies of
original size.
32 Bytes
[0040] During encryption, the scheduler will first determine if this address is in a Crypto Region, if not then bypass the Crypto Cores.
[0041] If the address is a hit for Crypto operation, it determines the type of operation based on the Encryption mode and Authentication mode for that region.
[0042] It will then schedule the required Crypto tasks for the Crypto Cores to implement that function including the HASH calculation.
[0043] It checks to see if a read/modify/write is required, then schedule a appropriate command.
[0044] During decryption the scheduler will first determine if this address is in a Crypto Region, if not then bypass the Crypto Cores.
[0045] If the address is a hit for Crypto operation, it determines the type of operation based on the Encryption mode and Authentication mode for that region.
[0046] Based on this information it will determine if it can start an early Crypto operation before the command is sent to the memory and before the read data is returned by the memory. This early operation enables high performance since the Crypto operation is started before the read data is sent back.
[0047] Also, it will check the HASH CACHE to determine if this command has a HIT, if a MISS the it will issue a HASH read before the read command is sent.
[0048] When the RD_DATA is sent back, a Scoreboard is used to determine which command it was associated with, this allows out of order commands to the external memory and out of order read data from the memory.
[0049] Once the read data arrives, the data will get sent to the Crypto Cores for processing.
[0050] For some types of Crypto Operations a Speculative Read Crypto operation can start when the Read command is sent to the Memory System. The result of this operation is stored in a Speculative Read Crypto Cache which enables the out of order response from the Memory System.
[0051] The Crypto Cores are a set of cores which can get used by encryption or decryption operations. The interface is simple, FIFO like with backpressure. If read traffic is 50% and write traffic is 50% then the allocation can be balanced. If write traffic is higher more Crypto Cores may be allocated to the write traffic.
[0052] This can get done by a static allocation, like a 60 to split or it can get done by a dynamic allocation to adapt to the current traffic patterns. This will insure the maximum utilization of the Crypto Cores.
[0053] The region checking function will verify that a command will not cross memory regions. If regions are crossed the command will be blocked. For WR DATA it will null all byte enables. For RD DATA will force zero on all.
[0054] DATA. A secure Error event is sent to the kernel. This prevents bad or malicious code from corrupting a secure area or getting access to a secure area.
[0055] The dictionary checker function will verify that the command is not doing a Dictionary attack by accessing the same memory location multiple times. If it violates these rules it will block the WR command from issuing a Crypto Operation and will null all byte enables. A secure Error event is sent to the kernel. This prevents bad or malicious code from determining the Crypto Keys used making the brute force attack the only possible method to break the encryption.
[0056] AES block 302 requires the following inputs:
Address of data word (from the command or calculated for a burst command), AES mode along with the Key size, Key and Initialization Vector (IV), Read or Write transaction type
[0060] The AES operation produces an encrypted or decrypted data word.
[0061] The MAC operation produces a MAC for Read and Write operations.
[0062] Table 2 defines the possible combinations of Encryption modes and Authentication modes. A total of 9 combinations are allowed. Note GCM is AES-CTR+GMAC and CCM is AES-CTR+CBC-MAC.
[0000]
TABLE 2
Authentication modes
Encryption modes
Disable
AES-CTR
AES-ECB+
Disable
Supported
Supported
Supported
GMAC
Supported
Supported
Not Supported
CBC-MAC
Not Supported
Supported
Not Supported
[0063] AES mode 0 is shown in FIG. 4 . The inputs to AES core 403 are the Input data 401 generated by scheduler 304 and the encryption/decryption key 402 . The output of AES core 403 and the EMIF read data during decryption or the bus write data during encryption is combined by Exclusive Or block 405 . The output of 405 is either cipher text during encryption, or plain text during decryption. AES mode 0 does not require a Read Modify Write operation.
[0064] AES mode 1 is shown in FIG. 5. 501 read data from the EMIF during decryption or write data from the bus during encryption is combined in XOR block 503 with the data 502 generated by scheduler 304 . The output of the XOR block 503 is input to AEA core 505 , together with the encryption or decryption key 504 . Output 506 of the AES core 505 is plain text during decryption, or cipher text during encryption. | A real time, on-the-fly data encryption system is shown operable to encrypt and decrypt the data flow between a secure processor and an unsecure external memory system. Multiple memory segments are supported, each with it's own separate encryption capability, or no encryption at all. Speculative decryption operations may be started when the memory used is capable of returning read data out of order. The full or partial results of the speculative operations are cached in order to allow matching the cryptographic operation to the read data when it arrives. | 6 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a formation method of a contact/through hole and more particularly, to a formation method of a contact hole or a through hole for electrically interconnecting an upper electrical conductor with a lower electrical conductor through a dielectric layer intervening between the upper and lower conductors, which is applicable to fabrication of an Ultra-Large-Scale Integrated circuit (ULSI).
2. Description of the Prior Art
Various patterning processes for electrically-conductive or dielectric layers are performed in a ULSI fabrication sequence.
With a typical patterning process of this sort, a wanted Pattern of geometrical shapes is formed in a resist film using a lithography technique. Then, unnecessary materials are selectively removed by an etching process using the resist film with the pattern as a mask. This mask serves to protest an underlying layer or layers with respect to the mask during this etching process.
In a formation process of a contact or through hole penetrating an interlayer dielectric layer to electrically interconnect an upper electrical conductors with a lower electrical conductor, two known masking techniques may be utilized.
A first one of the masking techniques utilizes a patterned photoresist film as a mask. A second one of the masking techniques utilizes a hard mask layer made of an inorganic material such as polycrystalline silicon (i.e., polysilicon).
When a contact or through hole is formed to penetrate an interlayer dielectric layer using the first masking technique, it is sufficient to pattern the photoresist film by a lithography technique, forming a window or hole pattern penetrating through the photoresist film. The patterned photoresist film thus obtained serves as a mask during a subsequent etching process, in which a penetrating hole serving as the contact or through hole is formed in the interlayer dielectric layer at a corresponding location to the window of the photoresist film.
To maintain the critical dimension control of the pattern on the photoresist film within a specific range, an etchant for this etching process needs to have a sufficient etch selectivity between the photoresist film and the interlayer dielectric layer so that the thickness of the photoresist film is kept approximately unchanged even after completion of this etching process.
Subsequently, the patterned photoresist film is removed by contacting this photoresist film with an oxygen (O 2 ) plasma that incinerates the photoresist film and/or a solvent in which the photoresist film is soluble.
Further, the contact or through hole formed in the interlayer dielectric layer is filled with an electrically-conductive material, resulting in an electrically-conductive plug that electrically interconnects an upper electrical conductor with a lower electrical conductor.
When a contact or through hole is formed in an interlayer dielectric layer using the second masking technique, first, the photoresist film is patterned by a photolithography technique, forming a window or hole pattern penetrating through the photoresist film. Next, the pattern of the photoresist film thus formed is transferred to an underlying hard mask layer (i.e., a first hard mask layer) by an etching process, forming a hole penetrating the hard mask layer at a location corresponding to the window of the photolithography film. The patterned photoresist film is then removed.
At this stage, if it is determined that the transferred hole onto the first hard mask layer is excessively large, a thin mask layer (i.e., a second hard-mask layer), which is made of the same material as that of the first hard mask layer, is formed on the first hard mask layer to have the same contour as that of the transferred hole. The second hard mask layer thus formed is then removed during a subsequent anisotropic dry etching process.
During this anisotropic dry etching process, although the second hard mask layer is removed from the horizontal surfaces such as the hole bottom of the hard mask layer and the hole top thereof, it is left unchanged from the vertical surfaces such as the hole sidewall of the hard mask layer. As a result, the initial size of the hole of the first hard mask layer is reduced by approximately twice the thickness of the second hard mask layer.
The second mask layer serves as a mask during a subsequent etching process, in which a penetrating hole serving as the contact or through hole is formed in the interlayer dielectric layer at a corresponding location to the hole of the second hard mask layer.
To maintain the critical dimension control of the pattern on the second hard mask layer within a specific range, an etchant for this etching process needs to have a sufficient etch selectivity between the second hard mask layer and the interlayer dielectric layer so that the thickness of the second hard mask layer is kept approximately unchanged even after this etching process.
A most-popular hard mask layer for contact-hole formation is made of polysilicon having a comparatively-high etching resistance during a reactive-ion etching (RIE) process for silicon dioxide (SiO 2 ). In this case, after an etching process for a contact hole is completed, a polysilicon hard mask layer is left on the surface of a semiconductor wafer. In addition to using polysilicon in the polysilicon hard mask layer, a polysilicon plug layer is commonly used for plugging a contact hole formed in a SiO 2 layer.
To further miniaturize each of the semiconductor devices and elements on the ULSI, for the upper electrical conductor a conductive layer or layers with an electrical resistance lower than the polysilicon hard mask and plug layers must be used. Hence, after depositing the polysilicon layer to form the plug, both the polysilicon hard mask layer and the polysilicon plug layer must be isotropically etched to either reduce their combined thickness or completely remove them from the wafer surface leaving the polysilicon in the contact hole intact. Since both layers are polysilicon, the etching process is simple. The lower-resistance electrically conductive layer is then deposited on top of the plug. As a result, the polysilicon-plugged contact hole is formed to penetrate through the SiO 2 layer in such a way that the underlying SiO 2 layer is exposed in the vicinity of the top end of the polysilicon-plugged contact hole.
A first typical example of the conventional formation methods of a contact hole using a polysilicon hard mask is shown in FIGS. 1A to 1H.
First, as shown in FIG. 1A, an impurity-doped region 202 is formed in a surface area of a silicon (Si) substrate 201. Next, an interlayer dielectric layer 203 of SiO 2 is formed on the substrate 201 to cover the impurity-doped region 202. A hard mask layer 204 of polysilicon is formed on the interlayer dielectric layer 203.
A patterned photoresist film 205 is formed on the hard mask layer 204. This photoresist film 205 has a window or contact-hole pattern 205A formed by a photolithography technique. The state at this stage is shown in FIG. 1A.
The hard mask layer 204 is selectively etched by an RIE process using the patterned photoresist film 205 as a mask, forming a hole pattern 206 penetrating the hard mask layer 204. The photoresist film 205 is then removed. Thus, the contact-hole pattern 205A of the photoresist film 205 is transferred to the hard mask layer 204, as shown in FIG. 1B.
Subsequently, the interlayer dielectric layer 203 is selectively etched by an RIE process using the polysilicon hard mask layer 204 as a mask, forming a contact hole 207 penetrating the dielectric layer 203, as shown in FIG. 1C. The contact hole 207 exposes the underlying impurity-doped region 202.
A polysilicon layer 208 for an electrically-conductive plug is formed on the hard mask layer 204 to bury the contact hole 207 by a Low-Pressure Chemical Vapor Deposition (LPCVD) process. The contact hole 207 is filled with the polysilicon of the layer 208, as shown in FIG. 1D.
The polysilicon plug layer 208 and the polysilicon hard-mask layer 204 are removed by an isotropic RIE process, resulting in a polysilicon plug 209 in the contact hole 207, as shown in FIG. 1E. The contact hole 207 is fully filled with the plug 209.
An electrically-conductive layer 210 is deposited on the SiO 2 interlayer dielectric layer 203 and the polysilicon plug 209, as shown in FIG. 1F. A patterned resist film 211 is formed on this layer 210 by a lithography technique, as shown in FIG. 1G.
Using the patterned resist film 211 as a mask, the electrically-conductive layer 210 is selectively etched by an RIE process, transferring the pattern of the resist film 211 to the electrically-conductive layer 210. Thus, an upper electrical conductor 212 is formed on the interlayer dielectric layer 203 and the plug 209, as shown in FIG. 1H. The upper electrical conductor 212 is contacted with the polysilicon plug 209 and is electrically connected to the impurity-doped region 202 in the substrate 201 through the plug 209.
A second typical example of the conventional formation methods of a contact hole using a polysilicon hard mask is shown in FIGS. 2A to 2H.
First, as shown in FIG. 2A, an impurity-doped region 202 is formed in a surface area of a silicon substrate 201. Next, an interlayer dielectric layer 203 of SiO 2 is formed on the substrate 201 to cover the impurity-doped region 202. A hard mask layer 204 of polysilicon is formed on the interlayer dielectric layer 203.
A patterned photoresist film 205 is formed on the hard mask layer 204. This photoresist film 205 has a window or contact-hole pattern 205A formed by a photolithography technique. The state at this stage is shown in FIG. 2A.
The hard mask layer 204 is selectively etched by an RIE process using the patterned photoresist film 205 as a mask, forming a hole pattern 206 penetrating the hard mask layer 204. The photoresist film 205 is then removed. Thus, the contact-hole pattern 205A of the photoresist film 205 is transferred onto the hard mask layer 204, as shown in FIG. 2B.
The above processes are the same as those in the first conventional method shown in FIGS. 1A to 1H.
Subsequently, unlike the first conventional method, a thin polysilicon layer 227 is deposited on the patterned polysilicon hard-mask layer 204, as shown in FIG. 2C. The thin polysilicon layer 227 is contacted with the interlayer dielectric layer 203 in the hole pattern 206.
The thin polysilicon layer 206 is then etched by an anisotropic RIE process to be selectively left on the side face of the hard mask layer 204 in the hole pattern 206. Thus, a polysilicon sidewall 228 is formed in the hole pattern 206 of the hard mask layer 204, as shown in FIG. 2D. Thus, the size of the hole pattern 206 is reduced by the sidewall 22B by approximately twice the thickness of the sidewall 228.
The interlayer dielectric layer 203 is selectively etched by an RIE process using the polysilicon hard-mask layer 204 and the polysilicon sidewall 228 as a mask, forming a contact hole 229 penetrating the dielectric layer 203, as shown in FIG. 2D. The contact hole 229 exposes the underlying impurity-doped region 202.
A polysilicon layer 208 for a plug is formed on the hard mask layer 204 to bury the contact hole 229 thus formed by a LPCVD process. The contact hole 229 is filled with the polysilicon of the layer 208, as shown in FIG. 2E.
The polysilicon plug layer 208, the polysilicon hard-mask layer 204, and the polysilicon sidewall 228 are removed by an isotropic RIE process, resulting in a polysilicon plug 229 in the contact hole 229, as shown in FIG. 2F. The contact hole 229 is fully filled with the plug 209.
An electrically-conductive layer 210 is deposited on the SiO 2 interlayer dielectric layer 203 and the polysilicon plug 209, as shown in FIG. 2F. A patterned resist film 211 is formed on this layer 210 by a lithography technique, as shown in FIG. 2G.
Using the patterned resist film 211 as a mask, the electrically-conductive layer 210 is selectively etched by an RIE process, transferring the pattern of the resist film 211 onto the electrically-conductive layer 210. Thus, an upper electrical conductor 212 is formed on the interlayer dielectric layer 203 and the plug 209, as shown in FIG. 2H. The upper electrical conductor 212 is contacted with the polysilicon plug 209 and is electrically connected to the impurity-doped region 202 in the substrate 201 through the plug 209.
The above-described first and second conventional methods using the polysilicon hard mask layer are sufficient for the present ULSIs. However, for the future ULSIs that will be further miniaturized, these methods have the following problems.
A first problem is that the conventional hard-mask technique is unable to be applied to the contact or through holes in the future ULSIs. The reason is as follows.
When each semiconductor device or element on the ULSI is further miniaturized to increase the number of the chips per wafer, each contact or through hole penetrating an interlayer dielectric layer will be further miniaturized. Consequently, the ratio of depth to width (i.e., the aspect ratio) of the hole will become larger. On the other hand, the aspect ratio of a corresponding hole pattern of a resist mask will not become large, because the resist mask needs to be thinner with the decreasing size of the semiconductor devices or elements. The thinner resist mask has a lower etching resistance.
To form the deep contact or through hole in the interlayer dielectric layer using the resist mask, an etching period of time is required to be set as longer. However, in this case, the resist mask is entirely etched away before the hole is completely etched in the interlayer dielectric layer because of the reduced etching resistance of the resist mask.
Accordingly, the above-described conventional hard-mask techniques have a limit for the further-miniaturized future ULSIs.
A second problem is that the conventional hard-mask techniques are readily applicable to only the case where the subsequent plugging method of a contact or through hole using a polysilicon plug includes deposition and etching processes of polysilicon. The conventional hard-mask techniques are not applicable to the future ULSIs with a minimum feature size of a quarter (1/4) μm, because an impurity-doped polysilicon plug filled into a hole with a large aspect ratio does not have a sufficient low electric resistance. Therefore, a metal plug needs to be filled into the hole instead of the polysilicon plug.
In this case, however, the polysilicon hard mask is unable to be s electively removed without etching the exposed silicon substrate at the bottom of the contact hole prior to deposition of a metal for the plug. On the other hand, if the polysilicon hard mask is left intact until deposition of the metal layer for the plug, and then removed during etching of the metal to form the upper electrical conductor, the required etching to remove the metal and polysilicon layers will become more complicated.
Further, the deposition temperature of polysilicon produced by a LPCVD process is typically 500 to 700° C. An electrically-conductive layer located under the interlayer dielectric layer has an insufficient heat resistance against the high temperature of 500 to 700° C. For example, an aluminum alloy will melt at a temperature ranging from 500 to 700° C. Therefore, the polysilicon hard mask is unable to be used to form a through hole in the interlayer dielectric layer.
To solve the above first and second problems, silicon nitride (Si 3 N 4 ) may be used as the hard mask layer instead of polysilicon. Alternately, Si 3 N 4 may be used as an etch stop layer located on the SiO 2 interlayer dielectric layer to utilize a high etch selectivity between Si 3 N 4 and SiO 2 . However, in this case, there arises another problem that the leakage current through a transistor junction increases because of a high stress of Si 3 N 4 .
There arises a further problem that Si 3 N 4 is unable to be used as a hard mask for a through hole because of a comparatively high deposition temperature of Si 3 N 4 .
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a formation method of a contact/through hole that is able to form both of a contact/through hole without raising such problems as those related to a resist mask.
Another object of the present invention is to provide a formation method of a contact/through hole that is capable of reducing the process temperature.
Still another object of the present invention is to provide a formation method of a contact/through hole that is applicable to the future ULSIs with a minimum feature size of a quarter μm.
The above objects together with others not specifically mentioned will become clear to those skilled in the art from the following description.
A formation method of a contact/through hole according to a first aspect of the present invention is comprised of the following steps (a) to (f):
(a) A dielectric layer is formed on a semiconductor substructure having a lower electrical conductor.
(b) A metal layer is formed on the dielectric layer.
(c) A patterned resist film is formed on the metal layer. The resist film has a pattern for a contact/through hole.
(d) The metal layer is selectively etched using the patterned resist film as a mask to thereby transfer the pattern of the resist film to the metal layer. Thus, a hole pattern is formed to penetrate the metal layer.
(e) The patterned resist film is removed from the etched metal layer.
(f) The dielectric layer is selectively etched using the etched metal layer as a mask to thereby transfer the hole pattern of the metal layer to the dielectric layer. Thus, a contact/through hole is formed to penetrate the dielectric layer and to extend to the lower electrical conductor.
The metal layer serves as a mask having a sufficient etch selectivity for the dielectric layer during the step (f). The contact/through hole is completed while the metal layer is subject to negligible thickness reduction with respect to its initial thickness due to an etching action during the step (f).
With the formation method of a contact/through hole according to the first aspect of the present invention, the pattern of the resist film for the contact/through hole is transferred to the metal layer, and then, the metal layer thus pattern-transferred is used as a hard mask during the etching step (f) for the dielectric layer.
The metal layer has a higher etching resistance to an etching action during the step (f) compared with the conventional resist film. Also, unlike the conventional resist film, the pattern contour of the metal layer does not tend to degrade even if the metal layer is subjected to the etching action and high temperature during the step (f).
Accordingly, any one of contact and through holes is able to be formed without raising such problems as those related to a resist mask.
Further, the metal layer may be formed by a Physical Vapor Deposition (PVD) process such as sputtering or evaporation or by any one of the various CVD processes. Therefore, compared with the first and second conventional methods described previously in which a polysilicon mask is used, any one of contact and through holes is able to be formed at decreased process temperatures.
As a result, this method is applicable to the future ULSIs with a minimum feature size of a quarter μm.
In the method according to the first aspect, the dielectric layer may be made of any dielectric material such as SiO x and SiN x . The metal layer may be made of any metal such as W, Ti, and TiN. The resist film may be made of a film of any resist material such as photoresist, Electron-Beam (EB) resist, and so on.
Each of the etching steps (d) and (f) may be performed by any one of the dry and wet etching processes.
In a preferred embodiment of the method according to the first aspect, a step (g) of removing the metal layer is provided after the step (f), and a step (h) of forming an electrically-conductive plug to fill the hole of the dielectric layer is provided after the step (g). The lower electrical conductor in the substructure is electrically connected to an upper electrical conductor formed on the dielectric layer through the plug.
It is preferred that the step (g) of removing the metal layer is performed by a wet etching process using an etchant having a good etch selectivity with respect to the dielectric layer and the exposed substructure.
In another preferred embodiment of the method according to the first aspect, a step (g) of forming an electrically-conductive plug to fill the hole of the dielectric layer without removing the metal layer is provided. The lower electrical conductor in the substructure is electrically connected to an upper electrical conductor formed on the dielectric layer through the plug. The remaining metal layer serves as a part of the upper electrical conductor.
A formation method of a contact/through hole according to a second aspect of the present invention is comprised of the following steps (a) to (h):
(a) A dielectric layer is formed on a semiconductor substructure having a lower electrical conductor.
(b) A first metal layer is formed on the dielectric layer.
(c) A patterned resist film is formed on the first metal layer. The resist film has a pattern for a contact/through hole.
(d) The first metal layer is selectively etched using the patterned resist film as a mask to thereby transfer the pattern of the resist film to the first metal layer. Thus, a hole pattern is formed to penetrate the first metal layer.
(e) The patterned resist film is removed from the etched, first metal layer.
(f) A second metal layer is formed on the etched, first metal layer. The second metal layer is contacted with the dielectric layer in the hole pattern of the first metal layer.
(g) The second metal layer is selectively etched by an anisotropic etching process, forming a metal sidewall by the remaining the second metal layer in the hole pattern of the first metal layer.
(h) The dielectric layer is selectively etched using a combination of the etched first metal layer and the metal sidewall as a mask to thereby transfer the hole pattern of the metal sidewall to the dielectric layer. Thus, a contact/through hole is formed to penetrate the dielectric layer and to extend to the lower electrical conductor.
The combination of the first metal layer and the metal sidewall serve as a mask having a sufficient etch selectivity for the dielectric layer during the etching step (h). The contact/through hole is completed while the first metal layer and the metal sidewall are subject to negligible thickness reduction with respect to their initial thickness due to an etching action during the etching step (h).
With the formation method of a contact/through hole according to the second aspect of the present invention, the pattern of the resist film for the contact/through hole is transferred to the first metal layer. Also, the metal sidewall is formed by the second metal layer to narrow the transferred pattern of the first metal layer. Then, the combination of the first metal layer thus pattern-transferred and the metal sidewall is used as a hard mask during the etching process (f) for the dielectric layer.
Each of the first metal layer and the metal sidewall has a higher etching resistance to an etching action during the etching process (f) compared a conventional resist film. Also, unlike a conventional resist film, the pattern contours of the first metal layer and the metal sidewall do not tend to degrade even if the first metal layer and the metal sidewall are subjected to the etching action and high temperature during the etching process (f).
Accordingly, any one of contact and through holes is able to be formed without raising such problems as those related to a resist mask.
Further, each of the first and second metal layers may be formed by any one of the PVD and CVD processes. Therefore, compared with the first and second conventional methods described previously in which a polysilicon mask is used, any one of contact and through holes is able to be formed at decreased process temperatures.
As a result, this method is applicable to the future ULSIs with a minimum feature size of a quarter μm.
In the method according to the second aspect, the dielectric layer may be made of any dielectric material such as SiO x and SiN x . Each of the first and second metal layers may be made of any metal such as W, Ti, and TiN. The resist film may be made of a film of any resist material such as photoresist, Electron-Seam (EB) resist, and so on.
Each of the etching steps (g) and (h) may be performed by any one of the dry and wet etching processes.
In a preferred embodiment of the method according to the second aspect, a step (i) of removing the first metal layer and the metal sidewall is provided after the step (h), and a step (j) of forming an electrically-conductive plug to fill the hole of the dielectric layer is provided after the step (i). The lower electrical conductor in the substructure is electrically connected to an upper electrical conductor formed on the dielectric layer through the plug.
It is preferred that the step (i) of removing the first metal layer and the metal sidewall is performed by a wet etching process using an etchant having a good etch selectivity with respect to the dielectric layer and the exposed substructure.
In another preferred embodiment of the method according to the first aspect, a step (j) of forming an electrically-conductive plug to fill the hole of the dielectric layer without removing the first metal layer and the metal sidewall is provided. The lower electrical conductor in the substructure is electrically connected to an upper electrical conductor formed on the dielectric layer through the plug. The remaining metal layer serves as a part of the upper electrical conductor.
In the formation methods according to the first and second aspects of the present invention, the semiconductor substructure may be optionally configured as necessary. However, the semiconductor substructure is typically formed by either a semiconductor substrate having an electrically-conductive region, or an electrically-conductive layer formed over a semiconductor substrate through at least one electrically-insulating layer.
In this specification, a "contact hole" is defined as a hole penetrating a dielectric layer, which is used for electrically interconnecting a lower electrical conductor formed in a semiconductor substrate (e.g., a diffusion region in a semiconductor substrate) with an upper electrical conductor such as a patterned, electrically-conductive layer through the hole. A "through hole" is defined as a hole penetrating a dielectric layer, which is used for electrically interconnecting a lower electrical conductor formed over a semiconductor substrate (e.g., a patterned, electrically-conductive layer) with an upper electrical conductor such as a patterned, electrically-conductive layer through the hole.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the invention may be readily carried into effect, it will now be described with reference to the accompanying drawings.
FIGS. 1A to 1H are partial cross-sectional views showing a conventional formation method of a contact hole using a polysilicon hard mask and a polysilicon plug, respectively.
FIGS. 2A to 2H are partial cross-sectional views showing another conventional formation method of a contact hole using a polysilicon hard mask and a polysilicon plug, respectively.
FIGS. 3A to 3G are partial cross-sectional views showing a formation method of a contact hole according to a first embodiment of the present invention, respectively.
FIGS. 4A to 4F are partial cross-sectional views showing a formation method of a contact hole according to a second embodiment of the present invention, respectively.
FIGS. 5A to 5I are partial cross-sectional views showing a formation method of a contact hole according to a third embodiment of the present invention, respectively.
FIGS. 6A to 6H are partial cross-sectional views showing a formation method of a contact hole according to a fourth embodiment of the present invention, respectively.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Preferred embodiments of the present invention will be described below with reference to the drawings attached.
FIRST EMBODIMENT
A formation method of a contact hole according to a first embodiment is shown in FIGS. 3A to 3G.
First, as shown in FIG. 3A, an n-type impurity such as arsenic (As) or phosphorus (P) is selectively diffused into the surface region of a p-type single-crystal silicon substrate 41, forming an n-type impurity-doped region 42 in the substrate 41. This n-type impurity-doped region 42 serves as a lower electrical conductor.
Second, an SiO 2 layer 43 with a thickness of 1 μm is deposited on the substrate 41 to cover the n-type impurity-doped region 42 by a CVD process. This SiO 2 layer 43 serves as an interlayer dielectric layer.
A tungsten (W) layer 44 with a thickness of 100 nm is deposited on the SiO 2 layer 43 by a sputtering process. This W layer 44 is contacted with the SiO 2 layer 43 with no intervening layer or structure such as a well-known, two-layered structure formed by an upper titanium nitride (TiN) sublayer and a lower titanium (Ti) sublayer. This is because the following reason.
If a W layer is deposited directly on a SiO 2 layer by a CVD process, which is termed a "CVD-W" layer, this CVD-W layer tends to flake from the SiO 2 layer. It has been known that this tendency is able to be prevented from occurring by intervening a two-layered structure of an upper TiN layer and a lower Ti layer between the W and SiO 2 layers. In this structure, the lower Ti layer serves as a contact layer for improving an adhesion property to the SiO 2 layer. The upper TiN layer serves as a barrier layer for preventing the chemical reaction of the Ti layer with a tungsten fluoride (WF 6 ) gas serving as a CVD reaction gas during a W CVD process.
On the other hand, if a W layer is deposited directly on a SiO 2 layer by a Physical Vapor Deposition (PVD) process such as sputtering or evaporation, which is termed a "PVD-W" layer, this PVD-W layer does not have a tendency to flake from the SiO 2 layer. This is because the PVD-W layer has a good adhesion property to the SiO 2 layer.
Following the sputtering process of the W layer 44, a patterned electron-beam (EB) resist film 45 with a thickness of 500 nm is formed on the W layer 44 thus deposited by an EB lithography technique. This resist film 45 has a window or a hole pattern 45A with a rectangular plan shape of 200 nm in width. The state at this stage is shown in FIG. 3A.
Subsequently, using the patterned EB resist film 45 as a mask, the W layer 44 is selectively etched by an RIE process, forming a penetrating hole 46 in the W layer 44, as shown in FIG. 3B. Thus, the hole pattern 45A of the resist film 45 is transferred to the W layer 44. The SiO 2 layer 43 is exposed from the W layer 44 in the hole 46. The EB resist film 45 is then removed by using oxygen (O 2 ) plasma or another popular process.
The RIE process for the W layer 44 is, for example, carried out under the following condition:
Gas Pressure: 8 mTorr,
Applied RF Power: 40 W
Reaction Gas: BCl 3 /SF 6 /N 2
Gas Flow Rate: 30/50/5 sccm
The SiO 2 layer 43 is selectively etched by an RIE process using the patterned W layer 44 as a hard mask, forming a contact hole 47 penetrating through the SiO 2 layer 43, as shown in FIG. 3C. The contact hole 47 is located just over the n-type impurity-doped region 42. The region 42 is exposed from the SiO 2 layer 43 through the contact hole 47.
The RIE process for the SiO 2 layer 44 is, for example, carried out under the following condition:
Gas Pressure: 30 mTorr,
Applied RF Power: 700 W
Reaction Gas: C 4 F 8 /CO/Ar
Gas Flow Rate: 10/140/60 sccm
The W layer 44, which has been used as the hard mask, is removed from the SiO 2 layer 43 by dipping the layer 44 into a hydrogen peroxide (H 2 O 2 ) at room temperature for two minutes. The state at this stage is shown in FIG. 3D.
A Ti layer 48A with a thickness of 30 nm and a TiN layer 48B with a thickness of 100 nm are successively deposited on the SiO 2 layer 43 by CVD processes to cover the contact hole 47, as shown in FIG. 3E. If the contact hole 47 has a size of approximately 0.25 μm or less, the hole 47 may be completely filled with the Ti and TiN layers 48A and 48B and thus, an additional CVD-W layer is not included in this embodiment. In this case, the lower Ti layer 48A serves as a contact layer improving the adhesion property of the upper TiN layer 48B to the SiO 2 layer 43. The upper TiN layer 48B serves as the main conductive layer of the upper electrical conductor 50 and electrically conductive plug 51.
As seen from FIG. 3E, within the contact hole 47, the lower Ti layer 48A is contacted with not only the inner side face of the SiO 2 layer 43 but also the n-type impurity-doped region 42 in the substrate 41.
Subsequently, a patterned EB resist film 49 is formed on the TiN layer 48B, as shown in FIG. 3F. The resist film 49 has a pattern with a width of 240 nm, which correspond to an upper conductor 50.
Using the patterned EB resist film 49 as a mask, the underlying Ti and TiN layers 48A and 48B are selectively etched by an RIE process, as shown in FIG. 3G. Thus, the layers 48A and 48B are selectively left in the area surrounding the upper opening end of the contact hole 47. This area corresponds to the resist film 49.
The RIE processes for the Ti/TiN layers 48A and 48B are, for example, carried out under the following condition:
Gas Pressure: 8 mTorr,
Applied RF Power: 75 W
Reaction Gas: BCl 3 /Cl 2
Gas Flow Rate: 30/70 sccm
The upper parts of the remaining Ti and TiN layers 48A and 48B serve as an upper electrical conductor 50. The lower parts of the remaining Ti and TiN layers 48A and 48B in the contact hole 47 serve as an electrically-conductive plug 51. The upper electrical conductor 50 is electrically interconnected with the n-type impurity-doped region 42 in the substrate 41 through the metal plug 51.
With the formation method of a contact hole according to the first embodiment, the pattern 45A of the EB resist film 45 for the contact hole 47 is transferred to the W layer 44 and then, the W layer 44 thus pattern-transferred is used as a hard mask during the RIE process for the SiO 2 layer 43.
The W layer 44 has a higher etching resistance to an etching action during the RIE process for the SiO 2 layer 43 compared a conventional resist film. Also, unlike a conventional resist film, the pattern contour of the patterned W layer 44 does not tend to degrade even if the W layer 44 is subjected to the etching action and high temperature during the etching process.
Accordingly, the contact hole 47 is able to be formed without raising such problems as those related to a resist mask.
Further, the W layer 44 is formed by a sputtering process. Therefore, compared with the first and second conventional methods described previously in which a polysilicon mask is used, a contact hole is able to be formed at decreased process temperatures.
As a result, this method is applicable to the future ULSIs with a minimum feature size of a quarter (1/4) μm.
It is needless to say that this method may be applied to the formation of a through hole.
SECOND EMBODIMENT
FIGS. 4A to 4F show a formation method of a contact hole according to a second embodiment.
The process steps shown in FIGS. 4A to 4C are the same as those in the first embodiment shown in FIGS. 3A to 3C. Therefore, the explanation about these steps is omitted here by adding the same reference numerals to the corresponding elements in FIGS. 4A to 4C for the sake of simplification.
In the method according to the second embodiment, unlike the first embodiment, the patterned W layer 44 is not removed from the SiO 2 layer 43.
Following the process step of FIG. 4C, a Ti layer 48A with a thickness of 30 nm and a TiN layer 48B with a thickness of 100 nm are successively deposited on the W layer 44 by CVD processes to cover the hole pattern 46 of the W layer 44 and the contact hole 47 of the SiO 2 layer 43, as shown in FIG. 4D. The holes 46 and 47 are filled with the Ti and TiN layers 48A and 48B. The lower Ti layer 48A serves as a contact layer improving the adhesion property of the upper TiN layer 48B to the SiO 2 layer 43 and the W layer 44. The upper TiN layer serves as an additional conductive layer in the upper electrical conductor 70 and as the main conductive layer for the electrically conductive plug 51.
As seen from FIG. 4D, within the holes 46 and 47, the lower Ti layer 48A is contacted with not only the inner side faces of the SiO 2 layer 43 and the W layer 44 but also the n-type impurity-doped region 42 in the substrate 41. The hole pattern 46 of the W layer 44 serves as a contact hole connecting with the contact hole 47 of the SiO 2 layer 43.
Subsequently, a patterned EB resist film 49 is formed on the TiN layer 48B, as shown in FIG. 4E. The resist film 49 has a pattern with a width of 240 nm, which corresponds to an upper electrical conductor 70.
Using the patterned EB resist film 49 as a mask, the underlying Ti and TiN layers 48A and 48B are selectively etched by an RIE process. Subsequently, the underlying W layer 44 is selectively etched by another RIE process using the patterned ES resist film 49 as a mask. Thus, the three layers 48A, 48B and 44 are selectively left in the area surrounding the upper opening end of the hole pattern 46, as shown in FIG. 4F. This area corresponds to the resist film 49.
The upper parts of the remaining Ti and TiN layers 48A and 48B and the remaining W layer 44 serve as the upper electrical conductor 70. The lower parts of the remaining Ti and TiN layers 48A and 48B in the contact hole 47 serve as an electrically conductive plug 51. The upper electrical conductor 70 is electrically interconnected with the n-type impurity-doped region 42 in the substrate 41 through the metal plug 51.
It is clear that the formation method of a contact hole according to the second embodiment has the same advantages as those in the first embodiment. There is an additional advantage that the upper conductor 70 is lower in electric resistance than the upper conductor 50.
It is needless to say that this method nay be applied to the formation of a through hole.
THIRD EMBODIMENT
FIGS. 5A to 5I show a formation method of a contact hole according to a third embodiment.
First, as shown in FIG. 5A, an n-type impurity such as As or P is selectively diffused into the surface region of a p-type single-crystal silicon substrate 41, forming an n-type impurity-doped region 42 in the substrate 41. This n-type impurity-doped region 42 serves as a lower electrical conductor.
Second, an SiO 2 layer 43 with a thickness of 1 μm is deposited on the substrate 41 to cover the n-type impurity-doped region 42 by a CVD process. This SiO 2 layer 43 serves as an interlayer dielectric layer.
A first tungsten (W) layer 44 with a thickness of 100 nm is deposited on the SiO 2 layer 43 by a sputtering process. This W layer 44 is contacted with the SiO 2 layer 43 with no intervening layer such as a well-known, two-layered structure formed by an upper titanium nitride (TiN) layer and a lower titanium (Ti) layer.
Following the sputtering process of the first W layer 44, a patterned EB resist film 45 with a thickness of 500 nm is formed on the W layer 44 thus deposited by an EB lithography technique. This resist film 45 has a window or a hole pattern 45A with a rectangular plan shape of 240 nm in width. The width is larger than that in the first embodiment. The state at this stage is shown in FIG. 5A.
Subsequently, using the patterned EB resist film 45 as a mask, the first W layer 44 is selectively etched by an RIE process, forming a penetrating hole 46 in the W layer 44, as shown in FIG. 5B. Thus, the hole pattern 45A of the resist film 45 is transferred to t he first W layer 44. The SiO 2 layer 43 is exposed from the first W layer 44 in the hole 46. The EB resist film 45 is then removed by using oxygen (O 2 ) plasma or another popular process.
Prior to the etching process of the SiO 2 layer 43, a second W layer 87 with a thickness of 30 nm, which is thinner than the first W layer 44, is deposited on the first W layer 44 by a CVD process, as shown in FIG. 5C. The second W layer 87 is contacted with the top of the SiO 2 layer 43 and the side face of the first W layer 44 in the hole 46.
The second W layer 87 is then etched by an isotropic etching process to be left on the side face of the first W layer 44, resulting in a sidewall 88 in the hole 46, as shown in FIG. 5D. The sidewall 88 is formed by the remaining second W layer 87. The sidewall 88 narrows the hole. pattern 46 by twice the thickness of the sidewall 88 (i.e., 30 nm×2=60 nm) to form a hole pattern 93 with a width of 180 nm. The combination of the first W layer 44 and the W sidewall 88 is used as a hard mask in the next RIE process for the SiO 2 layer 43.
The SiO 2 layer 43 is selectively etched by an RIE process using the combination of the first W layer 44 and the W sidewall 87 as a hard mask, forming a contact hole 89 penetrating the SiO 2 layer 43, a s shown in FIG. 5E. The contact hole 89, which is narrower in width than the contact hole 47 in the first embodiment, is located just over the n-type impurity-doped region 42. The region 42 is exposed from the SiO 2 layer 43 through the contact hole 89.
The first W layer 44 and the W sidewall 88, which have been used as the hard mask, are removed from the SiO 2 layer 43 by dipping the layer 44 and the sidewall 88 into H 2 O 2 at room temperature for two minutes. The state at this stage is shown in FIG. 5F.
A Ti layer 48A with a thickness of 30 nm and a TiN layer 48B with a thickness of 100 nm are successively deposited on the SiO 2 layer 43 by CVD processes to cover the contact hole 89, as shown in FIG. 5G. The hole 89 is filled with the Ti and TiN layers 48A and 48B.
As seen from FIG. 5G, within the contact hole 89, the lower Ti layer 48A is contacted with not only the inner side face of the SiO 2 layer 43 but also the n-type impurity-doped region 42 in the substrate 41.
Subsequently, a patterned EB resist film 49 is formed on the TiN layer 48B, as shown in FIG. 5H. The resist film 49 has a pattern corresponding to an upper conductor 92.
Using the patterned EB resist film 49 as a mask, the underlying Ti and TiN layers 48A and 48B are selectively etched by an RIE process, as shown in FIG. 5I. Thus, the layers 48A and 48B are selectively left in the area surrounding the upper opening end of the contact hole 89. This area corresponds to the resist film 49. The upper parts of the remaining Ti and TiN layers 48A and 48B serve as an upper electrical conductor 50. The lower parts of the remaining Ti and TiN layers 48A and 48B in the contact hole 89 serve as an electrically-conductive plug 51. The upper electrical conductor 92 is electrically interconnected with the n-type impurity-doped region 42 in the substrate 41 through the metal plug 51.
With the formation method of a contact/through hole according to the third embodiment, due to the same reason as that of the first embodiment, the same advantage as those in the first embodiment are obtained. There is an additional advantage that the narrowed contact hole 89 is realized compared with the first embodiment.
It is needless to say that this method may be applied to the formation of a through hole.
FOURTH EMBODIMENT
FIGS. 6A to 6H show a formation method of a contact hole according to a fourth embodiment.
The process steps shown in FIGS. 6A to 6E are the same as those in the third embodiment shown in FIGS. 5A to 5E. Therefore, the explanation about these steps is omitted here by adding the same reference numerals to the corresponding elements in FIGS. 6A to 6E for the sake of simplification.
In the method according to the fourth embodiment, unlike the third embodiment, the first W layer 44 and the W sidewall 88 are not removed from the SiO 2 layer 43.
Following the process step of FIG. 6E, a Ti layer 48A with a thickness of 30 nm and a TiN layer 48B with a thickness of 100 nm are successively deposited on the first W layer 44 by CVD processes to cover the hole pattern 93 of the first W layer 44 and the contact hole 89 of the SiO 2 layer 43, as shown in FIG. 6F. The holes 46 and 47 are filled with the Ti and TiN layers 48A and 48B.
As seen from FIG. 6F, within the holes 46 and 47, the lower Ti layer 48A is contacted with not only the inner side faces of the SiO 2 layer 43 and the first W layer 44 but also the n-type impurity-doped region 42 in the substrate 41. The hole pattern 93 of the first W layer 44 serves as a contact hole connecting with the contact hole 89 of the SiO 2 layer 43.
Subsequently, a patterned EB resist film 49 with a width of 240 nm is formed on the TiN layer 48B, as shown in FIG. 6G. The resist film 49 has a pattern corresponding to an upper conductor 112.
Using the patterned EB resist film 49 as a mask, the underlying Ti and TiN layers 48A and 48B are selectively etched by an RIE process. Subsequently, the underlying first W layer 44 is selectively etched by another RIE process using the EB resist film 49 as a mask. Thus, the three layers 48A, 48B, and 44 are selectively left in the area surrounding the upper opening end of the hole pattern 46, as shown in FIG. 6H. This area corresponds to the resist film 49.
The upper parts of the remaining Ti and TiN layers 48A and 48B and the remaining W layer 44 serve as the upper electrical conductor 112. The lower parts of the remaining Ti and TiN layers 48A and 48B in the contact hole 89 serve as an electrically conductive plug 51. The upper electrical conductor 112 is electrically interconnected with the n-type impurity-doped region 42 in the substrate 41 through the metal plug 51.
It is clear that the formation method of a contact hole according to the fourth embodiment has the same advantages as those in the first embodiment. There is an additional advantage that the upper conductor 12 is lower in electric resistance than the upper conductor 70 in the second embodiment.
It is needless to say that this method may be applied to the formation of a through hole.
TESTS
The following fact was known through the inventor's tests.
Even a polysilicon layer doped in situ with phosphorus (P) has a specific electric !resistance of approximately 600 μΩ·cm, which is comparable to the specific resistance of approximately 150 μΩ·cm of a sputtered TiN layer, of approximately 75 μΩ·cm of a sputtered Ti layer, and of approximately 14 μΩ·cm of a sputtered W layer.
Further, the following data (1) to (6) about the sheet resistance R S were obtained.
(1) A single PVD-W layer (thickness: 100 nm)
R S =1.43 Ω/□
(2) A single PVD-W layer (thickness: 200 nm):
R S =0.70 Ω/□.
(3) A single PVD-TiN layer (thickness: 100 nm):
R S =10.77 Ω/□.
(4) A single PVD-TiN layer (thickness: 200 nm):
R S =5.53 Ω/□.
(5) The combination of an upper PVD-W layer (thickness: 100 nm) and a lower PVD-TiN layer (thickness: 100 nm):
R S =2.23 Ω/□.
(6) The combination of an upper PVD-TiN layer (thickness: 100 nm) and a lower PVD-W layer (thickness: 100 nm):
R S =0.96 Ω/□.
Supposing that a CVD-TiN layer has a same electric resistance as that of a PVD-TiN, it was known that the lowest sheet resistance R S of 0.96 Ω/□ was obtained in the case (6), which corresponds to the above second and fourth embodiments. If the total thickness of 200 nm in the case (6) is excessively large, the lower PVD-W layer may be removed prior to the deposition of the CVD-TiN layer. However, in this case (3), the obtainable sheet resistance R S was increased up to 10.77 Ω/□.
In the case (5), the sheet resistance R S was decreased to only 2.23 Ω/□. If the PVD-TiN layer was etched away prior to the deposition of the CVD-W-layer (i.e., in the case (1) or (2)), the obtainable sheet resistance R S was 1.43 or 0.70 Ω/□. However, in the case (1) or (2), there was a disadvantage that the number and the complicacy of the necessary process steps became large, resulting in a higher formation cost of a contact hole.
Supposing that a CVD-W layer has a same electric resistance as that of a PVD-W, the lowest sheet resistance R S of 1.43 Ω/□ was obtained in the case (1), which corresponds to the above first and third embodiments. In this case (1), a PVD-W layer may be used instead of the two-layer structure of the TiN barrier layer and the Ti contact layer, which has been popularly used for a CVD-W layer. Accordingly, it was known that the lowest sheet resistance was realized with the use of a single PVD- or CVD-W layer.
VARIATIONS
In the above third and fourth embodiments, the first W layer 44 (and the W sidewall 88) is (are) selectively removed by a wet etching process using H 2 O 2 while protecting the impurity-doped region 42 in the substrate 41 and the SiO 2 layer 43. However, the present invention is not limited to these cases. The selective removal of the first W layer 44 (and the W sidewall 88) may be successfully accomplished by suitably changing the wet or dry etching chemistry according to the sort of the hard mask layer.
If a satisfactory etch selectivity is not accomplished by an RIE process, a suitable wet-etching process may be used.
For example, for a Ti hard mask, an etchant mainly containing NH 4 OH has a satisfactory etch selectivity to Si, SiO 2 , and TiN at a temperature of 20 to 40° C. In other words, this NH 4 OH-system etchant etches the Ti hard mask away while affecting no bad effects to the underlying materials. Therefore, the Ti hard mask may be used for etching a contact hole with respect to a silicon substrate and for etching a through hole with respect to a TiN-covered electrical conductor or TiN electrical conductor.
For a TiN hard mask, an etchant mainly containing H 2 SO 4 has a satisfactory etch selectivity to Si, SiO 2 , and W at a temperature of 20 to 40° C. In other words, this H 2 SO 4 -system etchant etches the TiN hard mask away while affecting no bad effects to the underlying materials. Therefore, The TiN hard mask may be used for etching a through hole with respect to a W-covered electrical conductor or W electrical conductor.
For a W hard mask, an etchant mainly containing H 2 O 2 has a satisfactory etch selectivity to Si, SiO 2 , Ti, and TiN at a temperature of 20 to 40° C. In other words, this H 2 O 2 -system etchant etches the W hard mask away while affecting no bad effects to the underlying materials. Therefore, The W hard mask may be used for etching a through hole with respect to a Ti-covered TiN electrical conductor or TiN-covered Ti electrical conductor.
Although the formation methods of a contact hole are explained in the above first to fourth embodiments, the present invention is not limited thereto. The p-type silicon substrate 41 may be of an n-type, and the n-type impurity-doped region 42 may be of a p-type. Further, although a W hard mask is used together with a TiN/Ti plug in the first to fourth embodiments, a Ti hard mask may be used together with a W plug.
Additionally, in the case of forming a through hole, the impurity-doped region 42 is replaced with a electrical conductor located below the dielectric layer 43.
Although an RIE process is used in the first to fourth embodiments, the present invention is not limited thereto. It is needless to say that any other etching process may be used.
While the preferred forms of the present invention has been described, it is to be understood that modifications will be apparent to those skilled in the art without departing from the spirit of the invention. The scope of the invention, therefore, is to be determined solely by the following claims. | A formation method of a contact/through hole is provided, which is able to form a contact or through hole without raising such problems related to a resist mask. After forming a dielectric layer on a semiconductor substructure having a lower electrical conductor, a metal layer is formed on the dielectric layer. A patterned resist film is formed on the metal layer. Then, the metal layer is selectively etched using a patterned resist film as a mask to transfer the pattern of the resist film to the metal layer, forming a hole pattern to penetrate the metal layer. The patterned resist film is removed from the etched metal layer. The dielectric layer is selectively etched using the etched metal layer as a mask to thereby transfer the hole pattern of the metal layer to the dielectric layer. Thus, a contact/through hole is formed to penetrate the dielectric layer and to extend to the lower electrical conductor. The metal layer serves as a mask having a sufficient etch selectivity for the dielectric layer during the etching step. The metal layer is subject to negligible thickness reduction with respect to its initial thickness due to an etching action. | 8 |
FIELD OF THE INVENTION
The present invention relates generally to communication systems. More particularly, the present invention relates to the decoding of encoded digital communication signals transmitted over a fading channel by generating side (reliability) information at the receiver.
BACKGROUND OF THE INVENTION
In TDMA (time-dimension multiple access) and other communications system, Rayleigh fading can present significant problems. Reliable communication over fading channels requires a large bit energy to noise ratio E b N o .
It is known that when communicating over a fading channel, the uncoded bit error rate (BER) decreases inverse linearly, rather than exponentially, with E b N o .
See, for example, Wozencraft et al., Principles of Communication Engineering, John Wiley and Sons (1965). While a desirably low error probability of 10 −5 can be achieved with a signal margin of only 13.4 dB for a noncoherent channel with no fading using binary orthogonal signaling, a signal margin of approximately 50 dB is required for a fading channel. See, for example, Viterbi et al., “Advances in Coding and Modulation for Noncoherent Channels Affected by Fading, Partial-Band, and Multiple-Access Interference,” Advances in Communications Systems, vol. 4, pp.279-308. Fading can also cause a loss in capacity and a reduced channel cutoff rate, as described in Stark, “Capacity and Cutoff Rate of Noncoherent FSK with Nonselective Rician Fading,” IEEE Trans. Commun., vol. COM-33, pp.1036-44 (September 1995).
To compensate for the signal and capacity loss of fading, most communication systems use some form of error-correction coding. For fading channels, most of the loss incurred from fading can be recovered using diversity (repetition) coding with some optimally-selected coding rate. For example, a repetition coding scheme can reduce the required signal margin necessary to achieve an error probability of 10 −5 from 50 dB to about 22 dB.
In a fading time-selective TDMA communication system, more than one data symbol is transmitted per time slot. If the system uses some form of coding, it is desirable to obtain information concerning the reliability of the symbols in a particular time slot, erase unreliable symbols, and use errors-and-erasures correction decoding. Such reliability information can include, for example, information indicative of the number of errors in a particular transmission, “soft” information used to decode the transmitted information, and other types of information. Thus, it is desirable to develop practical techniques for generating reliability information during each time slot.
The most common techniques for obtaining reliability information about a channel for coded communications systems fall generally into two categories: pre-detection techniques and post-detection techniques. Such techniques are described in for example, Pursley, “Packet Error Probabilities in Frequency-Hop Radio Networks-Coping with Statistical Dependence and Noisy Side Information,” IEEE Global Telecommun. Conf. Record, vol. 1, pp.165-70, (Sec. 1986). Pre-detection techniques are usually complex, involving methods such as energy detection or channel monitoring, and are therefore undesirable. Among Post-detection techniques, McEliece et al., “Channels with Block Interference,” IEEE Transaction on Inform. Theory, vol. IT-30, no. 1 (January 1984) suggested the transmission of test bits to learn about the channel. This method was applied to frequency-hopped multiple access channel to detect the presence of a bit in a given time slot in Pursley, “Tradeoffs between Side Information and Code-Rate in Slow-Frequency Hop Packet Radio Networks,” Conf. Record, IEEE Int'l. Conf. on Communications (June 1987). Similar techniques have been used to generate reliability information concerning a hop in a frequency-hopping spread-spectrum communication system in the presence of fading, as suggested in Hassan, “Performance of a Coded FHSS System in Rayleigh Fading,” Proceedings of the 1988 Conference on Information Sciences and Systems. Similarly, test bits can be used for carrier recovery and synchronization purposes. All of these methods described above involve making “hard” decisions on the test bits, resulting in a loss of power. In a conventional hard decision case, the receiver makes hard decisions on the test bits T. If more than a threshold number or percentage of the test bits in a timeslot are in error, then the detector declares all of the data symbols D transmitted during that slot as “bad”, and generates erasures for all symbols in the bad slot. If fewer than the threshold number are in error, then the detector declares all symbols transmitted during the slot as “good”, and delivers the corresponding estimates to the decoder. The performance measure of interest in the hard decision case is the probability of bit error, and the threshold must be chosen to minimize this probability. It would be desirable to reduce power loss in a practical, relatively simple method for generating reliability information.
SUMMARY OF THE INVENTION
According to exemplary embodiments of the present invention, side (reliability) information indicative of the reliability of the data transmitted in a time slot in a coded TDMA communication system subject to time-selective Rayleigh fading is generated by performing soft decisions to decode test bits. According to a first method, transmitted test bits known to the receiver are included in each slot, and a mathematical distance, such as the Euclidean or Hamming distance between the transmitted known test bit sequence and the corresponding received sequence, is determined by the receiver to decide whether the corresponding slot is reliable or not reliable. Alternatively, the channel state during a slot interval can be determined in a system which uses concatenated codes. According to this embodiment, the inner code is used to generate the information about the reliability of the data received over a channel. Significant enhancement in system performance, particularly with respect to the signal-to-noise ratio, is possible using the techniques of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention can be understood more fully by reading the following Detailed Description of the Preferred Embodiments in conjunction with the attached drawings, in which like reference indicia indicate like elements, and in which:
FIG. 1 is a block diagram of an exemplary communication system for transmitting encoded digital communication signals, in which the method of the present invention can be used;
FIG. 2 is a diagram of an exemplary test bit pattern contained in a TDMA burst; and
FIG. 3 is a block diagram of an exemplary communication system employing concatenated coding, in which the method of the present invention can be used.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 1, an exemplary communication system for transmitting encoded digital communication signals, in which the method of the present invention can be implemented, is shown. The system includes a channel encoder 10 for encoding digital data bits or symbols to be transmitted, a modulator 12 for modulating the encoded data symbols and transmitting the symbols over a transmission channel 14 to a receiver, a detector 16 for detecting/demodulating the receiver, and a decoder 18 for decoding the detected data symbols. The encoded, modulated symbols are preferably transmitted using time-division multiple access (TDMA), in which the symbols are transmitted in frames, each frame including multiple time slots. In a TDMA system, a communication channel is defined as one or more time slots in each frame which are assigned for use by a communicating transmitter and receiver. Each time slot contains numerous encoded bits or symbols. It will be appreciated that the present invention is applicable to other communication methods as well.
According to a first embodiment of the present invention, reliability information is generated by transmitting a known pattern of test bits or symbols, and using soft decisions to decode the test bits. An exemplary pattern of symbols transmitted in a time slot is shown in FIG. 2 . Such a pattern can be encoded in channel encoder 10 , modulated in modulator 12 , and transmitted over transmission channel 14 . Three types of symbols are transmitted in each time slot: information symbols, redundant symbols, and a set of known binary test symbols T. Collectively, the information symbols and the redundant symbols are referred to as data symbols D. The detector 16 determines the mathematical distance (e.g., Euclidean or Hamming) between the known pattern of transmitted test bits and the received test bits, compares the distance to a threshold, and generates an indication of the reliability of the data symbols in that time slot, based on the comparison. This indication of reliability can be used to indicate to the decoder that the data bits contained in a time slot are correct or incorrect. Thus, a mathematical distance measure between the test bits as transmitted and as received is used instead of hard decision trellis pruning. The test bits are most preferably interleaved within each time slot, as shown in FIG. 2 . Interleaving and deinterleaving can be performed by a suitable known interleaver and deinterleaver (not shown in FIG. 1 ).
Each symbol output by the detector 16 , in addition to the reliability information, to the decoder 18 is one of three types: a correct symbol, an erroneous symbol, or an erasure (loss of data). The decoder 18 preferably corrects the errors and erasures, and outputs information estimates for conversion to speech signals. If the error-and-erasure correcting capability of the particular code or codes is exceeded, the decoder fails, and the receiver outputs the information symbols of the vector received from detector 16 , including errors and erasures.
Alternatively, two decoders can be used in parallel, with a selector to choose the output of one of the decoders. According to such an embodiment, one decoder is used for errors-and-erasures correction, and the other decoder is used only to correct errors. Using such a scheme, when the error-and-erasures decoder fails to decode because the error and erasure correcting abilities of the code have been exceeded, the error correction decoder is selected to output the correct codeword. If both decoders fail, the receiver preferably outputs the information symbols of the received vector, including errors and erasures.
According to an alternative embodiment as shown in FIG. 3, a concatenated coding scheme is used. That is, two encoders 10 a,b and two decoders 18 a,b are used to perform encoding and decoding in two stages, respectively. The second (inner) encoder 10 a further encodes the symbols encoded by first (outer) encoder 10 b in each slot. The concatenated coded system of FIG. 3 preferably interleaves the outer code, and each inner-codeword is transmitted over a fixed channel. The system preferably uses the inner code to detect and correct errors, as will now be described. In a conventional hard decision decoder, the inner code corrects e errors and detects f errors (e≦f) provided e+f<d 1H , where d 1H is the minimum Hamming distance of the inner code. In the soft decision decoding scheme of the present invention, the inner code corrects all corrupted codewords or error patterns within a threshold mathematical (e.g., Euclidean or Hamming) distance Δ from a codeword, and otherwise outputs an erasure. The inner decoder may be used for detection of errors, correction of errors, or both. If the inner decoder is used for detection of errors only, then each erroneous symbol of the inner code will cause the outer decoder to generate an erasure. To correct errors that are not detected nor corrected by the inner code, the outer code preferably also corrects errors and erasures. The outer code is preferably a Reed-Solomon code, but it will be appreciated that other suitable codes can be used.
An example will now be described where a stream of data includes a fraction α which is channel encoded with a rate r 1 code and a fraction 1−α encoded with a rate r 2 code. Then the effective total rate r e is: r e = 1 α r 1 + 1 - α r 2
It will be appreciated that this example can be extended to a multi-rate coding scheme using this equation. The stream of data is assumed to be a frame in a time slot assigned to a single user in a TDMA system. For a half-rate coder in a TDMA system, a bandwidth expansion factor of 1/0.7 (6.5/4.5) or less is tolerable; i.e., r e =0.7. If only a portion of the data is to be protected, then r 2 =1 and r 1 ≥ 7 α 3 + 7 α
If α=¼, then a code rate r 1 ≧0.37 can be used. Thus for a concatenated coding system with a Reed-Solomon outer code and an extended Hamming (8,4) inner code, capable of correcting one error and detecting 2 errors, the Reed-Solomon code rate is around 0.74 (0.37/0.5).
Such a scheme can be implemented as follows. Outer encoder 10 b encodes every fourth bit with a Reed-Solomon (15,11) outer code. This code operates over Galois-Field GF(2 4 ) with 4-bit symbols. Each outer code symbol is further encoded by inner encoder 10 a using an extended Hamming code which corrects one error and detects two errors. If the inner decoder 18 a detects errors, then the corresponding Reed-Solomon symbol is considered unreliable, and the inner decoder 18 a informs the outer decoder 18 b of this unreliability. The outer decoder 18 b uses this soft information to correct e errors and r erasures such that 2e+r≦4. A suitable algorithm is the Berlekamp-Massey bounded-distance decoding algorithm including Galois field calculations as described in, e.g., Lin and Costello, Error Control Coding: Fundamentals and Applications, Chapter 6, available from Prentice Hall Publishers. It will be appreciated that other decoding algorithms can be used.
The inner decoder 18 a can be implemented by a soft decision or a maximum-likelihood decoder.
While the foregoing has included many details and specificities, it is to be understood that these are merely for purposes of explanation, and are not to be construed as limitations of the invention. Many modifications will be readily apparent to those of ordinary skill in the art which do not depart from the spirit and scope of the invention, as defined by the following claims and their legal equivalents. | A method and apparatus for decoding digitally encoded communication signals transmitted over a fading channel. According to the disclosed embodiments, a sequence of test bits are transmitted in each TDMA slots, and a mathematical distance (e.g., a Hamming or Euclidean distance) is calculated and used to determine reliability information indicative of the reliability of the bits or symbols in a received time slot. Alternatively, a concatenated coding scheme can be used to transmit digital communication signals. Reliability information can be generated using the inner code and the output of the inner decoder. | 7 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] Disclosed are pantyhose suitable for an expanded size range such as for plus-sizes and maternity which are knitted to include a panty wherein the front and back portions have different dimensions.
[0003] 2. Description of Related Art
[0004] Plus-size is a generic term for apparel targeted to larger individuals (for example, women over size 14 and men over size XL.) In the United States, over 30% of the total consumer base can be characterized as plus-sized, growing at a rate of 2% per year. Similarly, in Europe, there is an average of 23% of consumers characterized as plus-sized, lead by the United Kingdom with a 47% of the female population above size 14, followed by Germany at 29%. This size group is rapidly increasing in developing countries, such as China and Brazil at a rate of about 5% per year.
[0005] Plus-sized women have difficulty finding acceptable hosiery garments, i.e., pantyhose. Currently available hosiery garments are frequently unattractive with built in panels and/or cause the wearer discomfort. The result is that many women in this size range choose to wear pants/trousers rather than wearing pantyhose.
SUMMARY OF THE INVENTION
[0006] The pantyhose of some aspects provides a solution to the unattractive and uncomfortable features of currently available plus-sized hosiery. The pantyhose of some aspects eliminates the need for extra panels by knitting separate leg portions to form asymmetrical tubes which, when assembled, provide a front panty portion of the hosiery of a different are then the back panty portion. This provides hosiery that accommodates differently shaped women who may have a larger posterior region, or if pregnant, a larger tummy.
[0007] In one aspect is an article including pantyhose, the pantyhose including:
(a) a right leg portion including a right panty portion at a top end and a right toe portion at an opposite end; and (b) a left leg portion including a left panty portion at a top end and a left toe portion at an opposite end; wherein each of the right leg portion and the left leg portion each form an asymmetrical tube; the right panty portion has a front and back; the left panty portion has a front and back; and the front of the right panty portion and the front of the left panty portion have a different fabric construction than said back of the right panty portion and the back of the left panty portion, respectively.
[0014] In another aspect is a method for preparing pantyhose including:
(a) knitting a right leg portion including a right panty portion; (b) separately knitting a left leg portion including a left panty portion; and (c) attaching the right leg portion and the left leg portion; wherein each of the right leg portion and the left leg portion each form a tube; the right panty portion has a front and back; the left panty portion has a front and back; and the front of the right panty portion and the front of the left panty portion have a different fabric construction than the back of said right panty portion and the back of the left panty portion, respectively.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 shows the components of the pantyhose article.
[0023] FIG. 2 shows the finished pantyhose article.
DETAILED DESCRIPTION OF THE INVENTION
[0024] As used herein, the term “spandex” means a manufactured filament in which the filament-forming substance is a long chain synthetic polymer comprised of at least 85% by weight of a segmented polyurethane. A variety of different spandex compositions are useful with the pantyhose of some aspects such as polyether and co-polyether based spandex, among others. Specific examples of commercially available spandex yarns include those available under the tradenames LYCRA® 162B and LYCRA®902C available from INVISTA S.àr.l. of Wichita, Kans.
[0025] As used herein, the term “asymmetrical” as applied to the leg tubes or to the panty portion of the tubes or the panty portion of the pantyhose means that a different fabric construction is used to provide the front and back or each panty.
[0026] The pantyhose article of some aspects is knitted from two separate tubes which are attached to form the finished pantyhose. The two tubes may be attached in any suitable manner such as by sewing. The points of attachment in FIG. 1 are shown in the front ( 18 A, 18 B) and in the back ( 16 A, 16 B) and correspond to the seams ( 16 , 18 ) shown in FIG. 2 for the finished pantyhose article.
[0027] Referring to FIG. 1 , the asymmetrical tubes corresponding to a right leg portion 2 A and a left leg portion 2 B are shown. The right leg portion 2 A includes a right panty portion 4 A at a top end and a right toe portion 22 A at the opposite end and the left leg portion 2 B includes a left panty portion 4 B at a top end and a left toe portion 22 B at the opposite end. The right panty portion 4 A has a front 8 A and back 10 A and the left panty portion 4 B has a front 8 B and back 10 B. The front ( 8 A, 8 B) and back ( 10 A, 10 B) define the asymmetric portions as they have different areas of compression due to the differing yarn/fabric construction that eliminate the need for additional panels. By asymmetric, it is meant that the front portions ( 8 A, 8 B) have a different fabric construction or otherwise are not identical to the back portions ( 10 A, 10 B) on either side of the central lines ( 20 A, 20 B) as shown. Central lines ( 20 A, 20 B) represent an invisible line between the front and back portions of the assymetrical tubes which would otherwise represent a line of symmetry. This is accomplished by having a back ( 10 A, 10 B) of yarns providing lower compression than the front ( 8 A, 8 B) for plus-sized pantyhose or by having a lower compression in the front ( 8 A, 8 B) for maternity pantyhose.
[0028] The waistband ( 6 A, 6 B) of the pantyhose may include any suitable construction. To prevent or reduce rolling of the waistband, it may include a construction other than a folded over waistband and may include a single layer of fabric. To further reduce rolling of the waistband, the panty portion ( 4 A, 4 B) may be designed to extend above the waist of the wearer (not shown).
[0029] The pantyhose may include any suitable combination of elastic or elastomeric yarns with hard yarns. The elastomeric yarn may be included in every course or in alternate courses (other constructions may be useful where a patterned hosiery is desired). One suitable elastomeric yarn is spandex which may be used bare or covered. Examples of hard yarns include polyamide yarns such as nylon 6, nylon 6/6, nylon 10, nylon 12, nylon 6/10, nylon 6/12, and combinations thereof. The hard yarns may be flat or textured. The pantyhose may include yarns selected from polyamide covered spandex yarns and blends of polyamide covered spandex yarns with polyamide yarns.
[0030] To further enhance the comfort of the wearer, the panty portion of the hosiery may only include sheer yarns, and thus have reduced compression. The reduction or elimination of compression is achieved by the use of sheer yarns or lighter denier yarns and also may be achieved by reduction in spandex fiber content in the panty portion. The front and back of the panty may include different yarns which vary the compression either between the front and the back, or alternatively, in a portion of the front or back. For example, yarns in the bottom of the panty portion ( 4 A, 48 ) closest to the crotch 12 may provide less compression than the yarns near the waistband 6 . The yarn/fabric construction can vary depending on the desired compression effect. The top rows ( 13 A, 13 B—shown in FIG. 1 ) (closest to the waistband 6 ) may have different yarns than the bottom rows ( 11 A, 11 B—shown in FIG. 2 ) (closest to the crotch 12 ) for either the front of the panty portion ( 8 A, 8 B) or the back of the panty portion ( 10 A, 10 B). This may be for the top 50% to about 90% of the top rows, including about 70% to about 85% of the top rows of the panty portion. The bottom rows ( 11 A, 11 B—shown in FIG. 2 ) may optionally include yarns having higher denier or provide a heavier weight fabric to provide additional support at that location of the garment.
[0031] Suitable amounts spandex fiber may be about 10% to about 30% by total yarn weight, including about 12% to about 26%; and about 15% to about 22%.
[0032] To provide additional comfort the left leg portion and the right leg portion may include yarns that have the same denier or a heavier denier than yarns in the left panty portion and the right panty portion. By contrast, the leg portions (left and right) may have a construction selected from the group consisting of sheer, semi-opaque, and opaque. To further enhance comfort and reduce soreness during wear, the right leg portion and the left leg portion each may include an upper thigh portion 14 where the upper thigh portion includes reinforcing yarns.
[0033] The features and advantages of the present invention are more fully shown by the following examples which are provided for purposes of illustration, and are not to be construed as limiting the invention in any way.
EXAMPLES
[0034] The pantyhose of the some aspects is prepared using any suitable hosiery machine such as a hosiery knitting machine with 400 needles, 32 gauge, using the standard four feed system.
[0035] Examples for fiber content and construction include:
[0036] Sheer:
spandex %=26% Polyamide %=74% PANTY YARNS=spandex fiber of 45 dTex covered with 18 filament/6 dTex textured polyamide yarn in alternate courses with 16 filament/10 dTex textured polyamide yarn LEG YARNS=spandex fiber of 45 dTex covered with 18 filament/6 dTex textured polyamide yarn in alternate courses with 33 filament/20 dTex flat polyamide yarn
[0041] Semi-Opaque
spandex %=22% Polyamide %=78% PANTY YARNS=spandex fiber of 45 dTex covered with 18 filament/6 dTex textured polyamide yarn in alternate courses with 16 filament/10 dTex textured polyamide LEG YARNS=spandex fiber of 45 dTex covered with 18 filament 6 dTex textured polyamide yarn in alternate courses with 44 filament/34 dTex textured polyamide yarn
[0046] Opaque
spandex %=12% Polyamide %=88% PANTY YARNS=spandex fiber of 45 dTex covered with 18 filament/6 dTex textured polyamide yarn in alternate courses with 16 filament/10 dTex textured polyamide yarn LEG YARNS=spandex fiber of 45 dTex covered with 18 filament/6 dTex textured polyamide yarn (Feed 1,3) plated with 33 filament/20 dTex textured polyamide yarn in alternate courses with 33 filament 20 dTex textured polyamide yarn (Feed 2,4)
[0051] The panty portion was altered by using the following yarn in the bottom 15% of the rows in the back panty portion:
[0052] Spandex fiber covered with 18 filament/6 dTex flat yarn, plated with 22 filament/7 dTex flat yarn (Feed 1,3).
[0053] While there have been described what are presently believed to be the preferred embodiments of the invention, those skilled in the art will realize that changes and modifications may be made thereto without departing from the spirit of the invention, and it is intended to include all such changes and modifications as fall within the true scope of the invention. | The invention provides hosiery including a panty portion that is asymetrical. The hosiery provides a comfortable fit for a variety of different sizes including larger sizes and maternity. | 3 |
TECHNICAL FIELD
This invention relates in general to wastewater handling, and in particular, the invention relates to an improved deck drain pipe having features to promote simple and reliable mounting to a planar surface such as a wooden beam.
BACKGROUND OF THE INVENTION
Prefabricated plastic drain conduit is commonly used for drainage of decking around swimming pools. The typical conduit has a complex, often asymmetrical cross section that requires specialized connectors for attaching standard lengths of conduit together to span the entire length of a particular installation. To reduce the need for specialized connectors, the drain channel can be formed with a circular cross section adapted to couple with standard pipe.
When a concrete wall or other vertical surface forms the edge of a pool deck, the drain conduit is often secured to the vertical surface using concrete nails. These nails have to be driven into the concrete with greater force than nails driven into wood, which often results in cracking of the conduit, or deformation or misalignment of the conduit. Excessive deformation can lead to premature loss of the conduit's structural integrity and reduces draining capacity. Misaligned conduit forms a tripping hazard, prevents complete drainage, and is unsightly.
A need remained for a deck drain conduit that can be coupled with standard pipe, and has provisions to permit nailing the conduit to a support without unacceptable deformation or misalignment. As always, a deck drain that is reliable and long-lasting and can be made at minimal expense was also desired.
SUMMARY OF THE INVENTION
In general, a deck drain having the desired features and advantages is achieved by a main channel having a circular cross section, a top section having a top face designed to mount flush with the decking surface, and a mid section interconnecting the top section and the main channel. Nail guiding means attach to the mid section for accepting and directing a nail, preferably a concrete nail, through the mid section to secure the conduit to a support. Preferably, the nail guiding means comprises a pair of parallel planar projections extending away from the mid section, with each projection terminating at the end distal to the mid section in a flange to strengthen the projection and provide a surface for the nail head to press against.
A base plate extends out tangentially from the bottom of the main channel, allowing the conduit to stand unaided on a leveled surface. In addition, for each side of the conduit, the end of the base plate, the flanges on the nail guide projections, and a vertical wall of the top section are all aligned along a vertical axis to permit the conduit to be stably secured against a vertical surface without rocking. The base plate additionally acts as an anchor plate in installations where concrete is poured into the space on one or both sides of the conduit.
The main channel, mid section and top section are arranged along a major axis transverse to and intersecting with the main channel centerline. The advantages already discussed can be achieved with an asymmetrical conduit, i.e. one having the nail guiding means and the base plate located on only one side of the cross-sectional profile of the conduit. However, a symmetrical cross-sectional profile is preferred.
Additional features and advantages of the invention will become apparent in the following detailed description and in the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a section of deck drain according to the invention.
FIG. 2 is an end-on cross-sectional elevation thereof, as seen along line 2 — 2 in FIG. 1 .
FIG. 3 is an end-on elevation illustrating the use of the nail guiding means.
FIG. 4 is a cross-sectional elevation of the deck drain of the invention in a typical installation.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The deck drain 11 of the invention is an elongated conduit 13 as seen in FIG. 1, having a cross-sectional profile (FIG. 2) that defines three connected sections: a main channel 15 , a mid section 17 and a top section 19 . The deck drain 11 is preferably fabricated from extrusion molded polyvinyl chloride or polyethylene, but other materials can be used, including fiberglass and aluminum. The main channel 15 , the mid section 17 , and the top section 19 are aligned along a major axis 21 running transverse with and intersecting the main channel centerline 23 . The cross sectional profile of the conduit 13 does not need to be symmetrical about the major axis 21 , but symmetry is preferred and shown. It should be understood that discussion of the elements on one side of the major axis 21 will apply to corresponding elements on the other side of the major axis 21 as well.
The main channel 15 is circular in shape, with an opening 25 at the top to allow water to enter from the mid section 17 . The main channel's inside diameter is sized to accept and couple snugly with a piece of one-and-one-half inch Schedule 40 nominal size pipe, and can be varied to fit other pipe sizes. The mid section 17 is made up of two parallel sidewalls 27 and 29 connected to and extending vertically from the main channel opening 25 .
The top section 19 has a flat top face 31 designed to be set flush with the surface of the pool decking. A number of slot-shaped openings 33 are defined at periodic intervals along the length of the top face 31 . The openings are sized to allow water to drain into the conduit 13 while preventing debris from getting in and clogging the main channel 15 . Other opening shapes and configurations can be used, such as an array of round or square holes. If desired, the top face can be made removable to permit cleaning the conduit interior. Vertical faces 35 and 37 connect the top face 31 to a reducer 39 that in turn connects to the mid section 17 . Other configurations can be used.
The mid section 17 serves two main purposes: it interconnects the top section 19 and the main channel 15 , and it provides a point of attachment for the nail guiding means 41 to be described later. Although the term “nail guiding means” is used, it should be understood that the term applies to screws as well. The length of the mid section can vary, and can be the minimum necessary to attach the nail guiding means. The mid section can even be omitted altogether, and the nail guiding means 41 attached to the top section 19 . The nail guiding means 41 are preferably not attached to the main channel, since the nail holes that will inevitably result during installation can provide a path for leakage to the surrounding environment if the nail holes are below the water surface during draining.
As shown in FIG. 3, the nail guiding means 41 will retain a nail 42 driven into the conduit 13 in the direction of the arrow 44 in the proper vertical orientation for attachment to a support, and will provide additional structural strength to minimize deformation, misalignment, and cracking of the conduit 13 . Preferably, the nail guiding means 41 comprise a pair of parallel projections 43 and 45 extending away from the walls of the mid section 17 . Each projection 43 and 45 terminates in a small flange 47 and 49 that serves to strengthen the end of the respective projection 43 and 45 and provide a resting surface for the head of a nail. The projections 43 and 45 are preferably of sufficient length and spaced sufficiently close together to ensure that a nail passing through the projections 43 and 45 on one side of the conduit 13 will pass between the corresponding projections on the opposite side of the conduit 13 .
The nail guiding means can have other configurations. For example, tubular projections can be formed in the conduit at regular intervals, rather than the parallel planar projections shown. This configuration has the advantages that substantially less plastic is needed to make the nail guiding means, and that tubular guides will orient the nail properly in both the vertical and horizontal planes, rather than just in the vertical plane as with the preferred embodiment. However, tubular projections cannot be fabricated using normal extrusion molding techniques, and the resulting projections would be prone to breaking off during handling and installation, even with reinforcement.
A base plate 51 is tangentially attached to the bottom of the circular main channel 15 and permits the conduit 13 to be set upright on a leveled surface. This provides a convenient means for holding the conduit 13 in place prior to driving nails or screws through the nail guiding means 41 . Preferably, the end 53 of the base plate 51 , the projection flanges 47 and 49 , and the top channel's vertical wall 35 or 37 are all aligned along a vertical axis 55 , so that the conduit 13 will contact a vertical support face without wobbling, as shown in FIG. 4 . If desired, the outer surface 57 of the main channel 13 can also align along the vertical axis 55 . All the elements just listed need not be aligned along the vertical axis 55 , but the top section vertical wall 35 or 37 will always be one of the aligned elements, since the top face 31 must abut the vertical support face in order to prevent water from draining around the conduit 13 into the surrounding environment. FIG. 4 illustrates a typical installation for the deck drain 11 of the invention, where the conduit 13 is secured against a cement block 59 with nails 42 and a concrete deck 61 is then poured in against the exposed side of the conduit 13 .
The invention has several advantages over the prior art. The deck drain can be constructed simply and inexpensively using conventional methods. It is extremely rugged and durable. It provides means for the conduit to be secured with nails or screws without the deformation and misalignment of prior designs.
The invention has been shown in one embodiment, with alternative embodiments described in the text. It should be apparent to those skilled in the art that the invention is not limited to these embodiments, but is capable of being varied and modified without departing from the scope of the invention as set out in the attached claims. | A deck drain is made from extruded plastic with a cross section defining a substantially circular main channel, a mid section, and a top section having a top face with a plurality of openings defined therein. Nail guiding means are attached to the mid section, and direct a nail or screw through the mid section to secure the deck drain to a planar surface. Edges of two or more of the structural elements are aligned vertically to permit the deck drain to contact the planar surface without wobbling when attached. | 4 |
RELATED APPLICATION
[0001] This application is a continuation of and claims the benefit of priority under 35 U.S.C. §120 to U.S. patent application Ser. No. 12/981,035, filed Dec. 29, 2010, which application claims the benefit under 35 U.S.C. 120 119(e) of U.S. Provisional Patent Application Ser. No. 61/323,520, filed on Apr. 13, 2010, which applications are hereby incorporated by reference herein in their entirety.
FIELD OF THE INVENTION
[0002] The present subject matter relates generally to controlling functions in a hearing assistance device, and in particular to control of low power or standby modes of a hearing assistance device.
BACKGROUND
[0003] Modern hearing assistance devices, such as hearing aids, typically include a digital signal processor in communication with a microphone and receiver. Such designs are adapted to perform a great deal of processing on sounds received by the microphone. More and more hearing aids include a wireless communication option which provides a way to communicate with the hearing aid using another device. Such devices may have their own wireless protocols for communications or may use an industry standard protocol. However, there are situations where the wireless function of the hearing assistance device should be disabled, such as when flying (according to existing FAA rules). There are also situations where the energy consumption could be greatly reduced by placing the wireless radio functions in a hearing assistance device in a low power or standby state.
[0004] Hearing assistance device designs typically have a very limited amount of available volume to hold the electronics. A persistent problem is the placement of means to control the device. Hearing assistance devices have limited space to place controls. The limited space issues also magnify the need to conserve power in a hearing assistance device. Accordingly, there is a need in the art for apparatus and methods to provide improved control of a hearing assistance device, including a provision for low power or standby modes of operation of the device.
SUMMARY
[0005] Disclosed herein, among other things, are apparatus and methods to provide improved control of hearing aids and hearing aid applications. In one embodiment, a hearing assistance device includes a microphone, a receiver for playing sound to a wearer, a processor connected to the microphone and the receiver, and a radio connected to the processor. The processor is adapted to enter a low power or standby mode upon receipt of a predetermined command from one or more of the microphone or the radio. The processor is further adapted to exit a low power or standby mode upon receipt of a predetermined command from one or more of the microphone or the radio.
[0006] In one embodiment, a method of controlling modes of a hearing assistance device is provided. A predetermined command is received at a hearing assistance device processor from one or more of a hearing assistance device microphone or a radio connected to the processor. A low power or standby mode of the hearing assistance device is entered or exited upon receipt of the command. Other embodiments are possible without departing from the scope of the present subject matter.
[0007] This Summary is an overview of some of the teachings of the present application and not intended to be an exclusive or exhaustive treatment of the present subject matter. Further details about the present subject matter are found in the detailed description and appended claims. The scope of the present invention is defined by the appended claims and their legal equivalents.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 shows a block diagram of a hearing assistance device and a remote control according to one embodiment of the present subject matter.
DETAILED DESCRIPTION
[0009] The following detailed description of the present subject matter refers to subject matter in the accompanying drawings which show, by way of illustration, specific aspects and embodiments in which the present subject matter may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present subject matter. References to “an”, “one”, or “various” embodiments in this disclosure are not necessarily to the same embodiment, and such references contemplate more than one embodiment. The following detailed description is demonstrative and not to be taken in a limiting sense. The scope of the present subject matter is defined by the appended claims, along with the full scope of legal equivalents to which such claims are entitled.
[0010] FIG. 1 shows a block diagram of a hearing assistance device and a remote control according to one embodiment of the present subject matter. Many hearing assistance devices 110 , such as hearing aids, include a processor 116 that receives signals from a transducer, such as microphone 112 and processes those signals to be played over a speaker 114 (also known as a receiver in the hearing aid art). The hearing assistance device 110 includes at least one control 122 , which can be monitored by processor 116 and operations can be performed according to the control operation. More frequently, hearing assistance devices 110 also include a wireless communications aspect, such as radio 118 and an antenna 120 . Radio 118 in various embodiments is a receiver, a transmitter, or a transceiver. Various radio frequencies and modulation techniques can be employed without departing from the scope of the present subject matter. It is understood that the radio 118 and antenna 120 are optional in some embodiments set forth in this disclosure. It is further understood that embodiments that use radio 118 and antenna 120 may only require a reception function to work properly. It is further understood that in bidirectional radio communications that a transceiver function is required.
[0011] Optional remote control 130 is a device adapted to perform wireless communication with hearing assistance device 110 . In various embodiments it is understood that remote control 130 can be a dedicated remote control device. In various embodiments, remote control 130 is a cellular phone, personal data assistant, iPOD, iPhone, Google Android phone, Blackberry, computer, or other personal wireless device that can be used as set forth herein to perform the remote control function. It is understood that in various embodiments a software or firmware program can be loaded on the device to facilitate its use for the present subject matter.
[0000] A. Hearing Assistance Device Standby and/or Low Power Modes
[0012] In various embodiments, a user may wish to extend the battery life of his or her hearing assistance device, such as a hearing aid, by putting the hearing aid into a standby or low power mode. In one embodiment, standby mode disables most or all processing of audio information, thus muting the hearing assistance device (hearing aid). The device will enter a low power mode of operation and require another command or condition to wake the device up and return to normal operating mode. Various approaches can be used to enter and exit a low power or standby mode, including, but not limited to the following:
[0013] 1. Hearing Assistance Device Control
[0014] Control 122 can be configured to place the hearing assistance device 110 in standby mode and to return the device to normal operating mode. In one embodiment control 122 is used to toggle the device between operating mode and standby mode. In various embodiments control 122 is a button. In various embodiments control 122 is a touch sensor. In various embodiments control 122 is a proximity sensor. Other controls may be used without departing from the scope of the present subject matter. It is understood that different control operation sequences, including extended operation of the control and delays between operation of the control may be employed to perform mode selection. It is also possible that different controls can be used to change between standby and normal operating modes. For example, any of the wireless commands discussed herein can be used to exit standby mode and enter normal operating mode.
[0015] 2. Wireless Radio Frequency Command from Remote Control
[0016] In one embodiment of the present subject matter, a wireless command is issued from remote control 130 that puts the hearing assistance device 110 in standby mode. In radio frequency wireless applications, radio 118 includes a receiver configured to receive the command, decode it, and to place the hearing assistance device 110 into a form of standby mode. In various embodiments, radio 118 is further configured to periodically or occasionally listen for another command which returns the device to normal operation. Such modes are typically low power modes, such as, but not limited to, the reception mode set forth in U.S. patent application Ser. No. 12/643,540 application incorporated by reference herein. Other methods of exiting the standby state and returning to normal operating mode are possible in combination or in the alternative. In various embodiments, a control on the hearing assistance device 110 is operated to return the device to normal operating mode. For example, a control 122 can be used to sense one or more manual operations (including but not limited to one or more button press, touch sense, or proximity sense) to exit standby mode. Control 122 in various embodiments is a touch or proximity sensor. In various embodiments a return to normal operating mode is performed by opening and closing the battery compartment of the device 110 . In various embodiments device 110 returns to a normal operating mode upon certain triggering occurrences, such as a programmable timer reaching a setpoint, or multiple power cycles. In various embodiments a voice command can be detected to change modes. Another remote control approach is set forth in the following commonly owned patent application which is incorporated by reference in its entirety: U.S. Provisional Patent Application Ser. No. 61/220,994, filed Jun. 25, 2009, titled REMOTE CONTROL FOR A HEARING ASSISTANCE DEVICE. Other triggering occurrences are possible without departing from the scope of the present subject matter.
[0017] 3. DTMF Commands to Change Modes
[0018] In various embodiments dual tone multifunction (DTMF) tones are received by the hearing assistance device 110 and operating modes are changed based on the DTMF tones. Such tones can be received acoustically by microphone 112 from any audio source capable of generating such tones. The DTMF tones can also be send via a radio frequency message, received by radio 118 , decoded and processed by processor 116 to perform mode changes. It is understood that various tone sequences and combinations can be used to change modes from normal operating mode to standby mode or vice versa. Thus, it is understood that a single tone, pair of tones, or sequence if tones can be employed without departing from the scope of the present subject matter.
[0019] In one embodiment a unique DTMF tone or sequence is used to enter standby mode and another unique tone or sequence is used to enter normal operating mode. In further embodiments, the same message could be used to toggle between the modes. In various embodiments, the duration of a tone is used to change modes of the hearing assistance device 110 .
[0020] In various embodiments, the DTMF tones or sequence of tones is generated by a cellular phone or other telephone device. The cellular phone may include a software or firmware application downloaded to it to convert the cellphone into a multi-function remote that includes the capability of producing the necessary DTMF tones. Other platforms such as personal digital assistants PDA's, computers, or dedicated DTMF hardware equipped with audio outputs may be used to perform the remote control function. When two hearing aids are worn by a user, to ensure that both aids are enabled or disabled via DTMF it may be necessary to relay that information from one aid to the other via wireless transmissions prior to disabling the transmitter.
[0021] In one embodiment the hearing assistance device 110 may use the DTMF detection approach set forth in the following commonly owned patent application: U.S. Provisional Patent Application Ser. No. 61/176,734, filed May 8, 2009, titled CELL PHONE DETECTION FOR HEARING AIDS. Other DTMF approaches may be used without departing from the scope of the present subject matter.
[0000] B. Radio Standby and/or Low Power Modes
[0022] Modern hearing assistance devices capable of radio frequency wireless communications may require a method to disable the transmit function in certain circumstances. For example, whenever a passenger is aboard an aircraft the device's transmission function may have to be turned off. The Federal Aviation Administration (FAA) and other international air travel administrations restrict the use of electronic devices that emit electromagnetic information while in flight.
[0023] Also, when traveling outside their country of origin if communications are not compliant with other devices used in the destination country that the person is visiting it may be beneficial to disable a radio frequency wireless function. Industrial scientific and medical bands (ISM) are set aside for unlicensed operation of radio frequency communication in most countries. These bands differ from country to country in many cases. This makes it necessary for a traveler to be able to disable radio frequency wireless features when traveling outside of a particular regulatory domain.
[0024] One type of low power communication approach includes, but is not limited to, the low power approach set forth in U.S. patent application Ser. No. 12/643,540, filed Dec. 21, 2009, titled LOW POWER INTERMITTENT MESSAGING FOR HEARING ASSISTANCE DEVICES, which is hereby incorporated by reference in its entirety.
[0025] Various approaches can be used to enter and exit a low power or standby mode, including, but not limited to the following:
[0026] 1. Hearing Assistance Device Control
[0027] Control 122 can be configured to place the radio 118 in standby mode and to return the device to normal operating mode. In one embodiment control 122 is used to toggle the device between operating mode and standby mode. In various embodiments control 122 is a button. In various embodiments control 122 is a touch sensor. In various embodiments control 122 is a proximity sensor. Other controls may be used without departing from the scope of the present subject matter.
[0028] It is understood that different control operation sequences, including extended operation of the control and delays between operation of the control may be employed to perform mode selection. It is also possible that different controls can be used to change between standby and normal operating modes. For example, any of the wireless commands discussed herein can be used to exit standby mode and enter normal operating mode.
[0029] 2. Wireless Radio Frequency Command from Remote Control
[0030] In one embodiment of the present subject matter, a wireless command is issued from remote control 130 that puts the radio 118 in standby mode. In radio frequency wireless applications, radio 118 includes a receiver configured to receive the command, decode it, and to place the radio 118 into a form of standby or low power mode. In various embodiments, radio 118 is further configured to periodically or occasionally listen for another command which returns the device to normal operation. Such modes are typically low power modes, such as, but not limited to, the reception mode set forth in U.S. patent application Ser. No. 12/643,540 application incorporated by reference herein. Other methods of exiting the standby state and returning radio 118 to normal operating mode are possible in combination or in the alternative. In various embodiments, a control on the hearing assistance device 110 is operated to return the radio 118 to normal operating mode. For example, a control 122 can be used to sense one or more manual operations (including but not limited to one or more button press, touch sense, or proximity sense) to exit standby mode. Control 122 in various embodiments is a touch or proximity sensor. In various embodiments a return to normal operating mode is performed by opening and closing the battery compartment of the device 110 . In various embodiments radio 118 returns to a normal operating mode upon certain triggering occurrences, such as a programmable timer reaching a setpoint, or multiple power cycles. In various embodiments a voice command can be detected to change modes of radio 118 . Another remote control approach is set forth in the following commonly owned patent application which is incorporated by reference in its entirety: U.S. Provisional Patent Application Ser. No. 61/220,994, filed Jun. 25, 2009, titled REMOTE CONTROL FOR A HEARING ASSISTANCE DEVICE. Other triggering occurrences are possible without departing from the scope of the present subject matter.
[0031] 3. DTMF Commands to Change Modes
[0032] In various embodiments dual tone multifunction (DTMF) tones are received by the hearing assistance device 110 and operating modes of radio 118 are changed based on the DTMF tones. Such tones can be received acoustically by microphone 112 from any audio source capable of generating such tones. The DTMF tones can also be send via a radio frequency message, received by radio 118 , decoded and processed by processor 116 to perform mode changes. It is understood that various tone sequences and combinations can be used to change modes from normal operating mode to standby mode or vice versa. Thus, it is understood that a single tone, pair of tones, or sequence if tones can be employed without departing from the scope of the present subject matter.
[0033] In one embodiment a unique DTMF tone or sequence is used to enter standby mode and another unique tone or sequence is used to enter normal operating mode. In further embodiments, the same message could be used to toggle between the modes. In various embodiments, the duration of a tone is used to change modes of the radio 118 .
[0034] In various embodiments, the DTMF tones or sequence of tones is generated by a cellular phone or other telephone device. The cellular phone may include a software or firmware application downloaded to it to convert the cellphone into a multi-function remote that includes the capability of producing the necessary DTMF tones. Other platforms such as personal digital assistants PDA's, computers, or dedicated DTMF hardware equipped with audio outputs may be used to perform the remote control function. When two hearing aids are worn by a user, to ensure that both aids are enabled or disabled via DTMF it may be necessary to relay that information from one aid to the other via wireless transmissions prior to disabling the transmitter.
[0035] In one embodiment the hearing assistance device 110 may use the DTMF detection approach set forth in the following commonly owned patent application: U.S. Provisional Patent Application Ser. No. 61/176,734, filed May 8, 2009, titled CELL PHONE DETECTION FOR HEARING AIDS. Other DTMF approaches may be used without departing from the scope of the present subject matter.
[0036] In various embodiments, a voice activation algorithm is used to disable or re-enable the wireless transmissions or standby mode of a hearing aid. The wearer can disable wireless transmissions by using a voice command such as “deactivate wireless” or “wireless off” or conversely “Activate wireless” or “wireless on.” Similar commands may used for entering or exiting standby mode. The commands may be processed and interpreted by a digital signal processing unit (DSP), central processing unit (CPU), or other hardware on the hearing aid. Upon processing, the CPU carries out the command to disable/enable the functions present in voice command.
[0037] The following commonly owned patent documents are each hereby incorporated by reference in their entirety: U.S. patent application Ser. No. 12/643,540, filed Dec. 21, 2009, titled LOW POWER INTERMITTENT MESSAGING FOR HEARING ASSISTANCE DEVICES; U.S. Patent Application Ser. No. 60/687,707 filed Jun. 5, 2005, titled COMMUNICATION SYSTEM FOR WIRELESS AUDIO DEVICES; U.S. patent application Ser. No. 11/447,617, titled COMMUNICATION SYSTEM FOR WIRELESS AUDIO DEVICES; U.S. Provisional Patent Application Ser. No. 61/176,734, filed May 8, 2009, titled CELL PHONE DETECTION FOR HEARING AIDS; and U.S. Provisional Patent Application Ser. No. 61/220,994, filed Jun. 25, 2009, titled REMOTE CONTROL FOR A HEARING ASSISTANCE DEVICE.
[0038] The present subject matter can be used for a variety of hearing assistance devices, including but not limited to, tinnitus masking devices, cochlear implant type hearing devices, hearing aids, such as behind-the-ear (BTE), in-the-ear (ITE), in-the-canal (ITC), or completely-in-the-canal (CIC) type hearing aids. It is understood that behind-the-ear type hearing aids may include devices that reside substantially behind the ear or over the ear. Such devices may include hearing aids with receivers associated with the electronics portion of the behind-the-ear device, or hearing aids of the type having receivers in the ear canal of the user, such as receiver-in-the-canal (RIC) or receiver-in-the-ear (RITE) designs. It is understood that other hearing assistance devices not expressly stated herein may fall within the scope of the present subject matter.
[0039] This application is intended to cover adaptations or variations of the present subject matter. It is to be understood that the above description is intended to be illustrative, and not restrictive. The scope of the present subject matter should be determined with reference to the appended claims, along with the full scope of legal equivalents to which such claims are entitled. | Disclosed herein, among other things, are apparatus and methods to provide improved control of hearing aids and hearing aid applications. In one embodiment, a hearing assistance device includes a microphone, a receiver for playing sound to a wearer, a processor connected to the microphone and the receiver, and a radio connected to the processor. The processor is adapted to enter a low power or standby mode upon receipt of a predetermined command from one or more of the microphone or the radio. The processor is further adapted to exit a low power or standby mode upon receipt of a predetermined command from one or more of the microphone or the radio. Other embodiments are possible without departing from the scope of the present subject matter. | 7 |
CROSS REFERENCE TO RELATED APPLICATION
This is a continuation application of application Ser. No. 725,836, filed Sept. 23, 1976, and now abandoned.
BACKGROUND OF THE INVENTION
The invention relates to an apparatus for filtering the air used in spinning machines and installations as well as other textile industries to clean it from fibers, dust etc. The filtering system includes a rotating filtering drum which is mounted to rotate about a horizontal axis and through which air flows from the outside to the interior.
Filter systems of this type are often used in the textile industry, for example to filter the exhaust air from machine rooms in a continuous manner, especially to filter out fibers and dust such as enter the air in large quantities in such factories, although other applications are possible. Generally such filtering drums are relatively large and heavy because the quantities of air which must be cleaned are very large. Thus it is not a simple matter to construct bearings for such drums which can stand up to the very large weight and the possibility of soiling and which produce a problem of positioning due to the fact that at least one end of the drum is usually open.
In a known apparatus of this type (German Offenlengungsschrift No. 1,607,728) the filtering drum has a shaft affixed to the center of the closed end of the drum and mounted in an associated bearing and provided with a gear for rotary driving while the open end of the drum is carried on two rollers at its circumference. The bearing for the shaft as well as the carrier rolls are all located external to the drum itself, i.e., in a space which is filled with uncleaned air so that the mechanical devices, i.e., the carrier rollers and the bearings, etc., are exposed to the presence of fibers, dust, etc., and thus are subject to soiling and the associated wear and tear and must be cleaned very often or will begin to offer great resistance to the motion. While it would be possible to mount the bearing at the closed end of the drum within a housing having a rotary seal, this would increase the constructional expense and would make it difficult to cool the motor if the motor was also included in the housing.
In another known apparatus (French Pat. No. 1,231,871,) the drum is also carried on external bearing and carrier rolls. However, in this case, the electrical motor is located in the cleaned air current and drives the drum by means of a pinion which engages an internal rack at the open end of the drum. Thus the electric motor may be cooled with clean air but the very large circular rack which must be machined to exact tolerances is very expensive and thus substantially increases the total expense of the filtering system. Furthermore, the external bearings are subject to the soiling alluded to hereabove and all of the disadvantages resulting therefrom.
OBJECT AND SUMMARY OF THE INVENTION
It is a principal object of the invention to provide a filtering drum for air flow of the general type described above of such construction as to have bearings and drive means arranged to be protected against soiling and wear and tear while maintaining a simple construction and reliable operation. This and other objects are attained, according to the invention, by providing carrier rollers for the drum which are disposed in the interior space of the filtering drum.
By placing the carrier rollers of the filtering drum within the interior volume, these rollers and their bearings are surrounded only by air already cleaned by the filtering drum and thus are no longer exposed to rapid and heavy soiling. Furthermore, these bearings need not be additionally protected against soiling and are thus less expensive to produce. Cleaning of the bearings and the rollers can be performed at longer intervals and may be dispensed with altogether. Furthermore, the disposition of the carrier roller in the interior of the drum also permits locating the drive motor within the cleaned air without requiring the above-mentioned circular rack. Thus, in a preferred exemplary embodiment, at least one of the carrier rollers, and possibly all of them, are at the same time the driving rollers for the drum and may themselves be driven by a drive motor also preferably located within the interior of the drum. The considerable weight of the filtering drum makes it possible to embody the drive rollers as friction rollers not requiring gear teeth. The cooling of the electric motor is enchanced by the fact that the cooling air is clean. Another advantage of the novel location of the bearings for the filtering drum is that it is space-saving because it is located entirely within the drum so that the overall frame of the system and thus the overall length of the construction can be substantially of the same size as the drum itself.
The invention will be better understood as well as further objects and advantages thereof become more apparent from the ensuring detailed description of two exemplary embodiments of the invention taken in conjunction with the drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a schematic and partially sectional side view of one exemplary embodiment of the apparatus according to the invention;
FIG. 2 is a schematic representation of a section along the line 2--2 in FIG. 1;
FIG. 3 illustrates a variant of the axial securing means in the embodiment of FIG. 1; and
FIG. 4 is an axial sectional view of a second embodiment of the apparatus according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The filtering system 10 illustrated in FIGS. 1 and 2 for the purpose of filtering air and removing therefrom fibers, dust, etc., includes a filtering drum 11 and a very simple, narrow frame 12 in which are mounted carrier rollers 13, 14 and support rollers 15 for providing rotary bearing means for the filtering drum 11. The frame also supports a drive motor 16 for driving the drum 11 and a motorized suction mechanism 17 for continuously cleaning the filtering surface 19 of the filtering drum 11. The carrier rollers 13 and 14, as well as the support rollers 15, are located entirely within the interior volume defined by the cylindrical surface of the filtering drum 11 and are thus located in the cleaned air stream.
The filtering surface 19, which defines a right circular cylinder, extends nearly over the entire length of the filtering drum 11 and may be, for example, a perforated screen, a sieve, a metal mesh, a filtering cloth or the like, as required for the particular application. On both axial ends of this filtering surface 19, the drum 11 is provided with two metal rings 20, 21 which may have U profiles as shown, open to the outside, whose interior surfaces provide the tracks 23, 24 for the two carrier rollers 13, 14 and for the four alignment or support rollers 15. The left end of the filtering drum 11 as seen in FIG. 1 is closed off by a flat face plate 25 which is perforated in the center through which extends a horizontal beam member 26 included as a part of the frame 12. As shown, the beam 26 may be hollow and have a quadratic cross section. A rotary seal 27 provides an air seal between the face plate 25 and the beam 26. At both ends, the beam 26 is supported by two vertical hollow pedestals or standards 28,29 which are, in turn, fastened on a floor plate 30 or on the floor itself and thus are located outside of the filtering drum 11. The right end of the filtering drum 11 as seen in FIG. 1 remains substantially open for the passage of air and is aligned with an air flow aperture 31 in a wall 32 which separates the chamber or room 33 in which the drum 11 is located and which receives the air to be filtered from the clean air channel 34 which conducts the clean air to further locations, not shown. In a manner not shown, the air may be transported by a suction mechanism located within the clean air channel 34.
The weight of the filtering drum 11 is supported entirely by the two carrier rollers 13, 14 whose point of contact is the top (zenith) C of the carrier tracks 23, 24 FIG. 2 and which are fastened on a common shaft 35 to rotate in unison. The rollers are embodied as friction rollers and do not have teeth but may be covered with a friction surface. The shaft 35 may be carried in two locally fixed bearings, either sleeve bearings or roller bearings, which are disposed in radial arm means 37, 38 whose lower ends are fastened on the top of the beam 26. The shaft 35 carries a sprocket wheel 39 which cooperates with a pinion 40 of the electric motor 16 via a chain 41 and thus provides a drive means for driving the shaft 35 and the carrier rollers 13, 14. The carrier rollers 13, 14 are the only drive means for the drum 11 whose own great weight provides the necessary friction between the rollers and the tracks 23, 24. The geared electric motor 16 is preferably disposed near the closed face of the filtering drum 11 and close to its rotational axis because the air velocity is lowest in that location, so that only minimum amounts of dust which may still be present even in the cleaned air can reach the motor and the gear train 39, 40, 41.
Fastened to the bottom of the beam 26 are two plates 33' on each of which are mounted two arms 42, 43 extending radially with respect to the drum and located in mutually symmetric manner to extend below the central horizontal plane 45 of the drum 11. At their free ends, the arms 42, 43 are provided with alignment rollers 15 which complement the rotary mounting of the filtering drum 11 in such a manner as to define its center of rotation to be the central long axis of the beam and which prevent a change of the position of the drum in space, other than rotation. Preferably, the angle between each pair of arms 42, 43 is approximately 120° so that the alignment rollers and the carrier rollers 13, 14 are evenly distributed about the interior track 23, 24. The load on the alignment rollers 15 is very small since the carrier rollers 13, 14 substantially support the drum 11 by themselves which means that only the carrier rollers 13, 14 need to be constructed to carry high loads, thus saving expense. An annular seal 46 is disposed between the edge of the filtering drum 11 at its open end and the wall 32.
In the exemplary embodiment illustrated in FIG. 1, the face plate 25 and the outer wall of the beam 23 constitute a flange 47 both of whose sides represent guide tracks to insure the axial positioning of the drum 11. For this purpose, both of these sides are contacted by guide rollers 49, 50 whose vertical axes of rotation are defined in an extension 51 at the pedestal 28. In the exemplary embodiment shown, the guide rollers 49, 50 are outside of the drum but, since they absorb only small forces, they may be very small and thus may be easily sealed against contamination.
It is possible, however, to provide axial securing of the drum 11 in such a manner that it takes place within the drum and thus within the cleaned air, for example by means of special guide rollers which would cooperate with guide surfaces in the inside of the drum. Such guide surfaces could be, for example, the mutually facing surfaces 52, 53 of the rings 20, 21. However, in a variant embodiment, it may be provided, as illustrated in FIG. 4, that the carrier rollers 13, 14 and/or the alignment rollers themselves provide the axial positioning by suitable embodiment with circumferential collars 54 cooperating with the associated guide surfaces 52, 53 on the drum 11.
The suction device 17 which provides the continuous cleaning of the filtering surface 19 of the drum 11 is of per se known construction including a carriage 57 continuously running back and forth on tracks 56 and carrying a suction nozzle 59 with an attached hose 60 which may be attached to a suitable suction device so that the nozzle continuously removes contaminations from the filtering surface and transports it to a collection point.
The second embodiment of the invention, illustrated in the axial view of FIG. 3, is differentiated from the embodiment of FIGS. 1 and 2 substantially in that the function of each of the carrier rollers 13, 14 is taken over by two carrier rollers 13', 13" although FIG. 3 shows only the pair of rollers 13', 13" which associates with the track 23. The other pair of rollers, which would cooperate with the second track 24, may be embodied in an identical manner. The shafts of each pair of rollers which are congruent in the illustration of FIG. 4 are connected by a common shaft 35', 35" as was the case for the carrier rollers 13, 14 in the embodiment of FIG. 1. Preferably, it may be provided that all four carrier rollers, i.e., the two pairs of rollers each of which has a roller 13', 13", are individually driven, which is accomplished in the illustrated example by providing a sprocket wheel 39 on each of the shafts 35', 35" and a chain 41 which envelops both sprocket wheels 39 as well as the pinion 40 of the electric motor 16, whereby the electric motor 16 drives both shafts 39 and thus drives all four carrier rollers in common. The pairs of rollers lying in the same diametral plane and thus associated with the same track 23 or 24 are displaced by an angle of approximately 120° and located symmetrically with respect to the vertical plane 44 of the drum 11. They are mounted at the upper free ends of radial arms 37', 37" which radiate from a carrier plate mounted on the beam 26 and they are located generally above the horizontal longitudinal plane 45 of the drum 11.
The embodiment 10' of FIG. 3 does not include alignment rollers such as were present in the embodiment of FIGS. 1 and 2 because the carrier rollers 13', 13" are so disposed as not only to support the drum but also to prevent any lateral displacement of their axes of rotation, i.e., they serve at the same time as alignment rollers. Furthermore, these rollers are also drive rollers and are suitably embodied as friction rollers. Any details of the embodiment of FIG. 3 not shown may be identical to those illustrated in FIGS. 1 and 2; in particular, the elements 11, 12, 16 and 17 may be exactly the same as those shown in FIGS. 1 and 2.
While it is preferably provided that one face of the filtering drum 11 is closed, the invention is easily applicable to drums in which both ends are open, because the apparatus according to the invention does not require a central bearing shaft mounted on one face of the drum. In the case where both ends are open, an especially large capacity and a great air flow is achieved, which may be useful in certain applications. The two open ends of the drum could be in mirror symmetry and each could be flush with an associated wall.
While it is advantageous to provide the chain drive 39, 40, 41, other suitable drive mechanisms are, of course, possible; in particular, the drive motor 16 may provide its power via a drive shaft and via at least one bevel gear train connected to at least one of the shafts 35, 35', 35". In another possible embodiment, not shown, a geared motor could be coupled directly to one of the shafts 35, 35', or 35". Other possibilities for applying motive power exist.
In many cases, it may be suitable to provide axial positioning of the drum 11 at the places where the rotary axis penetrates the drum, for example by means of axial thrust bearings, and especially suitably in the vicinity of the annlar seal 27.
The foregoing relates to preferred exemplary embodiments of the invention, it being understood that other embodiments and variants are possible within the spirit and scope of the invention, the latter being defined by the appended claims. | An air filtering system for large installations such as spinning machine rooms, textile factories, etc., has a rotating drum with permeable walls through which air is aspirated to the interior of the drum while the accumulated contaminants are removed during the rotation of the drum by a reciprocating vacuum cleaner. In order to protect the bearings of the drum and the drive mechanism from contact with uncleaned air, the drum is carried by rollers which contact only the interior surface of the drum. The drive motor and transmission are also placed inside the drum. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of British Patent Application No. 0623237.5 filed 22 Nov. 2006 and which is hereby incorporated by reference.
BACKGROUND
1. Field of the Invention
The present invention relates to the field of data processing and database technologies, and, more specifically, to issuing syncpoints during the execution of a batch application.
2. Description of the Related Art
In very complex data processing systems such as global banking networks run on mainframe systems, a transaction processing system (e.g., Customer Information Control System (CICS) from IBM) manages the interface between application programs and database records. If an application wishes to access a record (i.e., a customer's bank account balance stored on a database), then the transaction processing system will mediate the transaction. The transaction processing system will recall the record from the database, and will place a lock on the record so that no other application can access or update that specific record. Any read or write data requests relating to the record are then processed. Once the application program has finished with the record, a syncpoint is issued to the transaction processing system which results in the lock being removed from the record. No other application can access the record while the lock exists.
In addition to application programs accessing records via a transaction processing system, batch applications are also used to update records. A batch application executes a set of updates which can include very large sets that can consume computing resources of transaction processing systems for an execution period. In the context of a banking system, a batch application may relate to a series of over the counter transactions that need to be applied to the computerized records representing the various bank account details of the customers.
Conventional transaction processing systems impose a lock on all batch records while the batch is processing. Locking the records to prevent other applications from accessing or manipulating the locked records permits the systems to “roll-back” batch manipulations whenever a batch execution fails or whenever an authorized administrator wishes to cancel or reverse an active batch process for any reason. The roll-back removes all changes occurring after the syncpoint so that a data processing system state and record content is the same as it was when the syncpoint was established.
In other words, before a batch application is started, a syncpoint is established. Once a batch application is started, each update is processed in turn. This involves accessing each record to be updated, locking the record and then performing the necessary update. Once all of the records referred to in a batch application have been processed, then a new syncpoint can be issued and all of the locked records can be unlocked and therefore made available to other applications. If a problem occurs during the batch, the pre-batch syncpoint can be used to reverse changes resulting from the aborted batch execution.
Historically, batch processes were executed at times when real-time updates were disallowed. For example, real-time updates occurred during workday hours and batch processes were executed at night when no real-time accesses occurred. Consequently, batch applications did not interfere with other processing since a system could be taken “offline” during a time in which real-time accesses are blocked. All batch applications could be executed at this time. However, with the globalization of markets, integration of databases with remote computing systems, data center consolidation, Web database access capabilities for users (i.e., online banking), remote workplace software tools (e.g., CITRIX, PCANYWHERE, etc.), flexible work hours, and other factors have minimized or eliminated acceptable times for placing a system offline. That is, today's database systems often need to be available for real-time accesses twenty four hours a day. Any downtime can result in significant loss of service to key customers, and/or a loss of revenue to a data processing system owner.
Businesses wish to achieve this capability without expensive changes to their data processing infrastructure. For example, businesses do not wish to replace or re-code batch processing applications which are working properly, yet which have an unfortunate side effect of preventing database access when executing. At the same time, businesses are compelled to provide competitive services which can include 24/7 Internet access to customer records and/or data availability to business partners and their computing systems at all times.
No solutions without significant drawbacks currently exist for handling batch processing while providing increased data availability. For example, data processing centers have implemented partial solutions that are mainly based on tools that minimize the impact of the unavailability of data: either by careful scheduling or by limiting either the scope (i.e., number of data sets included in a batch) of batch related “outages” or their duration. The inadequate solutions that do exist often limit the ability of users to stay current and adopt new technologies since the partial solutions impose limitations that conflict with implementation requirements of emerging technologies, system upgrades, and new data processing or data interfacing techniques. To date, no solution has attempted to eliminate batch related downtime or outages entirely.
SUMMARY OF THE INVENTION
The present invention discloses a solution that automatically decomposes a batch process into multiple units of work without changing code of a pre-existing batch application. In the solution, the batch application is first analyzed to identify a set of processing segments or units of work, where each unit of work is of a size that minimizes interference with other data accesses. That is, each unit of work is designed so that a set of records involved in the unit of work will be locked for an acceptably low period of time. Configurable parameters and/or automated system monitoring tools can be used to define the acceptable period of record locking, which in turn is used to define a set of records included in each unit of work. Once each unit of work is defined, these units can execute one at a time. A syncpoint can be established for each unit before it is executed, which locks the records included in the unit. After the unit of work executes, the record lock can be released and a new syncpoint can be established for the next unit. If an execution problem occurs, execution for the unit of work can be terminated and changes can be “rolled back” to the syncpoint. Thus, changes made by the terminated execution of the unit can be discarded and restored to a pre-execution state.
The present invention can be implemented in accordance with numerous aspects consistent with the material presented herein. For example, one aspect of the present invention can include a method of increasing database record availability during a batch process execution. In the method, a batch process of a batch application can be identified. The batch process can be associated with a batch set of database records which are accessed by the batch process as the batch process executes. The batch process can be analyzed to determine multiple units-of-work. Each unit-of-work can be associated with a unit set of the database records, wherein the unit set can be a smaller subset of the batch set. A next one of the units-of-work can be determined. A syncpoint can be established for the determined unit-of-work. Records in the unit set associated with the determined unit-of-work can be locked so that applications other than the batch application are unable to modify the records while locked. The records in the unit can be batch processed in accordance with programmatic instructions of the batch application. Upon success of the processing step, the records in the unit set can be unlocked. The method steps can be repeated until each unit-of-work is processed.
Another aspect of the present invention can include a method of operating a data processing system. The method can execute a batch application. The batch application can read one or more inputs from one or more data files, can perform updates on one or more records according to the inputs, and can issue a new syncpoint when each of the updates are completed. The method can monitor the inputs read from the data file. A predefined algorithm can operate based upon the monitored inputs. Output of the predefined algorithm can cause new syncpoints to be periodically issued during the execution of the batch application. Issuing a new syncpoint can commit record updates of a previous partial batch processing step. User intervention can occur whenever syndication feed updates are obtained by the feed reader.
Still another aspect of the present invention can include a data processing system that includes a processing function arranged to execute a batch application. This processing function can execute to reading one or more inputs from one or more data files, to perform updates on one or more records according to the inputs, and to issue a syncpoint when said updates are completed. The processing function can monitor the inputs to operate a predefined algorithm based upon the monitored inputs. A syncpoint can be periodically issued during the execution of the batch application according to an output of the predefined algorithm.
It should be noted that various aspects of the invention can be implemented as a program for controlling computing equipment to implement the functions described herein, or as a program for enabling computing equipment to perform processes corresponding to the steps disclosed herein. This program may be provided by storing the program in a magnetic disk, an optical disk, a semiconductor memory, or any other recording medium. The program can also be provided as a digitally encoded signal conveyed via a carrier wave. The described program can be a single program or can be implemented as multiple subprograms, each of which interact within a single computing device or interact in a distributed fashion across a network space.
It should also be noted that the methods detailed herein can also be methods performed at least in part by a service agent and/or a machine manipulated by a service agent in response to a service request.
BRIEF DESCRIPTION OF THE DRAWINGS
There are shown in the drawings, embodiments which are presently preferred, it being understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown.
FIG. 1 is a schematic diagram of a data processing system that decomposes a single batch execution into multiple units of work, each having its own syncpoint.
FIG. 2 is a further schematic diagram of the data processing system in accordance with an embodiment of the inventive arrangements disclosed herein.
FIG. 3 is a flow diagram of a method of operating a data processing system that decomposes a single batch execution into multiple units of work, each having its own syncpoint.
FIG. 4 is a schematic diagram of embodiment of the data processing system in accordance with an embodiment of the inventive arrangements disclosed herein.
DETAILED DESCRIPTION OF THE INVENTION
The invention provides a solution permitting transparent file sharing for existing batch applications. The solution allows transaction processing systems (e.g., Customer information Control System (CICS) and batch applications) to make updates to the same records (e.g., Virtual Storage Access Method (VSAM) files) at the same time. The solution provides a mechanism to break up the existing batch applications into multiple units-of-work by issuing syncpoints on behalf of the batch application for each unit-of-work. Each unit-of-work can be processed individually which locks records for that unit only during unit processing. When processing errors occur, the system can restore itself back to the syncpoint associated with the unit, thus restoring system information to a pre-processing state. Thus, unlike traditional batch processes that lock large sets of records during a batch process, the present solution only locks small sets of records at a time. The solution is able to execute batch functions of unmodified batch applications without requiring a processing system to enter an online state.
More specifically, many batch application systems read input from one or more very large sequential files. The batch application processes the data from a set of these input records and then performs an update or multiple updates to a set of records. Appropriately, at that point a syncpoint would be issued because a set of logically connected updates has been performed. The data processing system can base the positioning of syncpoints on information in the records in the sequential input files that are input to the batch application. For example, in one situation each record in a sequential input file will start a new unit of work. Alternatively, batches of records in the input file are processed as a single unit of work in the batch application. A user would have the capability of influencing which records in the input stream would signal that a new unit of work is starting.
Another way in which the system may decide on the issuing of syncpoints is that there might be, in a particular application, a certain fixed number of input records that would be processed as a single unit of work. If that number were one, then the system would know that each record read from the input stream would be starting a new unit of work. Not only would each update be starting a new unit of work, it would be terminating the previous unit of work. Thus this would be an appropriate place to take a syncpoint.
In a different system, each unit of work would process, for example, four input records. The data processing system would then count the input records and when the fifth input record is read the system would know that a new unit of work was starting and the old unit of work was finished and the system would issue a syncpoint. In other cases, certain data in an input record might signify the start of a new unit of work. for example, when byte 1 of a record contains ‘S’, then that might indicate the start of a new unit of work. Thus every time the batch application reads a record with an ‘S’ in the first byte, the system would note that a new unit of work was starting and the old unit of work had finished and a syncpoint would be issued. The information in the record would already exist but the system provides an interface for the user to tell the system which information to look for in a record update. By these techniques the data processing would be able to issue syncpoints at appropriate points on behalf of the batch application and there would therefore be recoverable data records without any need to change the batch application.
FIG. 1 shows a data processing system 10 which includes a computer 12 which can be a mainframe computer that provides a processing function. The mainframe 12 can include a batch application 14 that can have its own address space within the mainframe 12 . The mainframe 12 can also include a transaction processing system 16 . The transaction processing system 16 can be any hardware/software/firmware configured to process database records. In one embodiment, the transaction processing system 16 can be a CICS region within the mainframe 12 .
When the batch application 14 is being executed, the application 14 communicates with one or more data files 18 and applies updates to records 20 being stored by databases 22 . The execution of the batch application 14 comprises reading one or more inputs from the data files 18 , performing updates on one or more records 20 according to the inputs read from the data files 18 , and ultimately issuing a syncpoint when the updates are completed. As each record 20 is accessed by the batch application 14 during the execution of the batch, then that record 20 is locked until the completion of the batch application 14 where the syncpoint releases the locks on all of the records 20 accessed by the batch application 14 . In contrast, system 10 permits the records 20 to be updated while region 16 remains online. System 10 can operate without modifying batch application 14 .
In the known conventional arrangement, while the batch application 14 is being executed, the CICS region 16 is not part of the batch process and is either taken offline while the batch application 14 is executing or will be unable to access any records 20 that have had locks placed on them by the batch application 14 .
FIG. 2 shows the data processing system 10 of FIG. 1 adapted according to an embodiment of the invention. An application program 24 is written into the same address space as the batch application 14 (without any amendment needed to the batch application 14 ). This application program 24 is configured to monitor the inputs read from the data files 18 and operates a predefined algorithm 26 based upon the monitored inputs.
The predefined algorithm 26 can be simple and, for example, can be arranged to generate an output following a fixed number of inputs being read from a data file 18 . The data processing system 10 of FIG. 2 is arranged periodically to issue a syncpoint during the execution of the batch application 14 , according to the output of the predefined algorithm 26 . This is achieved by intercepting data requests from the batch application 14 to the records 20 and routing the intercepted data requests through the transaction processing system 16 (the CICS region). This intercepting of the data requests from the batch application 14 to the records 20 can comprise intercepting internal communications within the batch application 14 . In effect, the application program 24 monitors calls within the batch application 14 , and internal communications to the output interface of the batch application 14 are intercepted by the program 24 and rerouted through the CICS region 16 .
In this configuration, the step of periodically issuing a syncpoint during the execution of the batch application 14 , is carried out by the transaction processing system 16 . The system of FIG. 2 is arranged, effectively, to break up the batch defined by the data files 18 into a series of much smaller units of work. A syncpoint is issued after each of these smaller units of work is completed. This ensures that large numbers of records 20 are not held by locks and the CICS region 16 can mediate access to records 20 required by other application programs. If CICS receives a data request from another application in respect of a record 20 for which a lock is being applied for the current unit of work that the batch application 14 is processing, then this is handled in the normal manner and CICS will hold that data request until the lock is released.
The algorithm 26 is monitoring the input to the batch application 14 and is defining a break up of the inputs into separate units of work. An output is generated that triggers the issuing of a syncpoint when a unit of work completes, according to the rules of the algorithm 26 . The predefined algorithm 26 can be operated to generate an output following detection of a data flag in an input being read from a data file 18 . This data flag can be selected by a user, and can be as simple as looking for a stated character at a specific bit position in an input received from the file 18 .
FIG. 3 summarizes the methodology used in the data processing system 10 of FIG. 2 . The method of operating the data processing system 10 comprises the step S 1 of executing the batch application 14 , the step S 2 of monitoring the inputs read from the data files 18 , the step S 3 of operating the predefined algorithm 26 based upon the monitored inputs, and finally the step S 4 of periodically issuing a syncpoint during the execution of the batch application 14 , according to an output of the predefined algorithm 26 .
FIG. 4 shows another embodiment of the data processing system 10 , which uses an application program 28 “CICS Anytime” to mediate between the batch application 14 and the transaction processing system 16 , a standard implementation of the CICS. The batch application 14 includes a shared Virtual Storage Access Method (VSAM) file request/response unit which interfaces with CICS Anytime. CICS Anytime is responsible for the issuing of syncpoints, and for restarting (auto and manual) the system and request mapping. CICS Anytime is connected to a restart database 30 , a checkpoint database 32 , a Multiple Virtual Storage Resource Recovery Services (MVS RRS) unit 34 and an external CICS interface (EXCI) unit 36 . CICS connects to the shared records stored as VSAM datasets in a database 38 .
The primary objective of CICS Anytime is to eliminate completely CICS application outages caused by the inability of CICS to share its VSAM file data. CICS Anytime enables non-CICS programs to access VSAM file data through CICS, so that CICS appears to treat each batch application 14 as just another transactional user. In return for getting access to CICS's file data on behalf of batch applications, CICS Anytime has to ensure that the client's non-CICS applications are operating as if they were well-designed transactional applications. This requires short duration units of work, changes being hardened when committed, changes able to be backed out upon failure of units of work, the proper handling of error conditions, coordinated with CICS handling, and able to restart from a recent point in time and back out failures, following any catastrophic failure.
CICS Anytime has to be applicable to existing batch applications 14 without requiring them to be modified. Many existing batch applications, by their structure, are unable to operate as well-designed transactional applications. If they were run as is, many batch applications 14 would hold CICS locks for the duration of the batch job, which could be a very long time. This would result in CICS online transactions suffering long delays due to waits for locks, or being aborted due to timeouts or, in the worst case, deadlocks.
Rather than requiring compliance of non-CICS client programs, such as the batch application 14 , through redesign, CICS Anytime provides for these applications the infrastructure to achieve compliance. In practice, CICS Anytime takes control by intercepting VSAM requests that the batch applications make, and creating granularity, both in the stream of data requests in normal operation and in the sequence of events in restart and recovery in the event of job or system failure.
This role is crucial when working with unchanged, legacy, batch applications 14 . These aged applications 14 are usually unsophisticated, with simple error handling and little, if any, recovery and restart capability. CICS Anytime addresses these problems by issuing syncpoints on behalf of the batch application 14 , and tracks and manages status and restart processing in the event of any failure.
In summary, the functions of CICS Anytime include intercepting and redirecting file requests from z/OS batch applications, where the files are being managed by CICS, dynamically splitting up large batch jobs, presenting them to CICS as a series of small units of work, and working with MVS Resource Recovery Services and CICS Recovery Manager to coordinate commitment or rollback of file changes. CICS Anytime also automatically inserts syncpoints at appropriate places in the job stream, with user defined syncpoint frequency by, for example, time or number of updates and can dynamically split up large batch jobs into checkpoint restartable units with user defined checkpoint frequency by, for example, time or number of updates. CICS Anytime can handle communication failures such that they are transparent to the batch applications and do not require a restart, where possible, can ensure back-out of all changes to all shared files to last successful syncpoint, and can provide restart from the last successful checkpoint.
The use of the system of FIG. 4 with the CICS Anytime eliminates the batch window for virtually all batch applications without requiring any batch application code changes, with minimal job control language (JCL) or procedure changes and without having any significant negative impact on CICS transaction response time, service levels or availability.
CICS Anytime operates without having a significant effect on batch application performance. In particular, elapsed time remains acceptable. Depending on the nature of the application there are likely to be user requirements to have certain batch jobs complete within a certain time frame. For example, check clearing has to be completed by a statutory time every day so banks can settle financial positions between themselves. The current quantification of acceptable is no more than a doubling of batch job elapsed time. In this embodiment, the backing up of data files before and after the batch job are no longer required.
The system of FIG. 4 has a mechanism to provide basic file data sharing between multiple MVS address spaces. This is provided by the reuse of CICS file sharing, based on MRO Function Shipping and the CICS mirror transactions. Although this is currently limited to sharing between CICS Address Spaces, the EXCI capability, which provides Distributed Program Link (DPL) between a non-CICS MVS address space and a CICS Server address Space, can be used. The CICS Anytime solution is based on enhancements to EXCI to support shipping of File Control requests.
With a basic file sharing mechanism, the system is able to provide a way to intercept application file requests without requiring any program changes to the batch application 14 . This function also maps the VSAM request issued by the batch application 14 to a CICS format that can be shipped by EXCI to the CICS system that owns the files. This must all be done in a way that is transparent to the existing batch application 14 , such that it appears to the batch application 14 that the batch application 14 is still accessing a non-shared file under exclusive control.
This means that, for example, new errors that could arise due to the fact that there are new components being used must be handled within CICS Anytime and not exposed to the batch application 14 in any way. Locking is fundamental to a shared environment but is totally absent from the exclusive control environment in which the batch application 14 thinks it is running. Therefore locking, timeouts, and deadly embrace situations all need to be catered for transparency with respect to the batch application 14 .
With the capabilities provided above, the system provides a solution which provides transparent file sharing for existing batch jobs. However, with no other changes, the existing batch job would run as a single long running unit-of-work (UOW). This means that the batch job would potentially hold thousands of locks in CICS and the online CICS regions would grind to a halt and potentially fail.
Therefore, there is provided a mechanism to break the existing batch job up into multiple UOWs by issuing syncpoints on behalf of the batch application 14 . CICS Anytime has to issue the syncpoints at appropriate places and the syncpoints are handled by MVS Resource Recovery Services unit 34 which acts as the syncpoint coordinator.
The system also needs to provide checkpoint restart and positional recovery. The capabilities described above (of issuing periodic syncpoints) result in a break up of the batch job and stop it having a significant impact on online CICS transaction response times. However, should the batch job fail, there needs to be a mechanism which will allow the system to be restarted either automatically or manually from the point of failure. What is possible is the ability to create restart checkpoints at periodic intervals, not too often (less frequently than the syncpoints mentioned above) as they are expensive to create (Elapsed Time, CPU and I/O) and then to restart from the most recent checkpoint.
The system is running transactionally and therefore CICS will back-out of any uncommitted units of work to the most recent syncpoint in cases of failure. What is provided is the ability for the batch job which is restarted at the most recent checkpoint to “catch-up” with the state of the data as backed out to the most recent syncpoint. This is achieved by use of the Restart Dataset which is created by CICS Anytime and contains a record of all the VSAM requests and responses since the most recent checkpoint.
The present invention may be realized in hardware, software or a combination of hardware and software. The present invention may be realized in a centralized fashion in one computer system or in a distributed fashion where different elements are spread across several interconnected computer systems. Any kind of computer system or other apparatus adapted for a carrying out methods described herein is suited. A typical combination of hardware and software may be a general purpose computer system with a computer program that, when being loaded and executed, controls the computer system such that it carries out the methods described herein.
The present invention also may be embedded in a computer program product, which comprises all the features enabling the implementation of the methods described herein, and which when loaded in a computer system is able to carry out these methods. Computer program in the present context means any expression, in any language, code or notation, of a set of instructions intended to cause a system having an information processing capability to perform a particular function either directly or after either or both of the following: a) conversion to another language, code or notation; b) reproduction in a different material form.
This invention may be embodied in other forms without departing from the spirit or essential attributes thereof. Accordingly, reference should be made to the following claims, rather than foregoing the specification, as indicating the scope of the invention. | The present invention discloses a solution that automatically decomposes a batch process into multiple units of work without changing code of a pre-existing batch application. In the solution, the batch application is first analyzed to identify a set of processing segments or units of work, where each unit of work is of a size that minimizes interference with other data accesses. Once each unit of work is defined, these units can execute one at a time. A syncpoint can be established for each unit before it is executed, which locks the records included in the unit. After the unit of work executes, the record lock can be released and a new syncpoint can be established for the next unit. If an execution problem occurs, execution for the unit of work can be terminated and chances can be restored to the syncpoint. | 6 |
[0001] This is a continuation-in-part of PCT Application Serial No. 2006014939 filed on Apr. 20, 2006, which claimed the benefit of a prior provisional application U.S. Ser. No. 60/674,826 filed on Apr. 26, 2005.
FIELD OF THE INVENTION
[0002] This invention relates to composite warp knitted and braided constructs, each comprising two types of yarns having significantly different absorption/biodegradation and strength retention profiles to produce warp-knitted meshes and braided sutures exhibiting bimodular changes in their properties when used as surgical implants.
BACKGROUND OF THE INVENTION
[0003] Blending of non-absorbable fibers having distinctly different individual physicochemical properties is a well-established practice in the textile industry and is directed toward achieving unique properties based on the constituent fibers in such blends. The most commonly acknowledged examples of these blends include combinations of (1) wool staple yarn and polyethylene terephthalate (PET) continuous multifilament yarn to produce textile fabrics which benefit from the insulating quality of wool and high tensile strength of the polyester; (2) cotton staple yarn and PET continuous multifilament yarn to produce water-absorbing, comfortable (due to cotton), strong (due to PET) fabrics; (3) nylon continuous multifilament yarn and cotton staple yarn to achieve strength and hydrophilicity; and (4) cotton staple yarn and polyurethane continuous monofilament yarn to yield water-absorbing, comfortable elastic fabrics. The concept of blending non-absorbable and absorbable fibers was addressed to a very limited extent in the prior art relative to combining polypropylene (PP) with an absorbable polyester fiber in a few fibrous constructs, such as hernial meshes, to permit tissue ingrowth in the PP component of these meshes and reducing long-term implant mass, as the absorbable fibers lose mass with time. However, the use of totally absorbable/biodegradable blends of two or more yarns to yield fibrous properties that combine those of the constituent yarns is heretofore unknown in the prior art. This provided the incentive to pursue this invention, which deals with totally absorbable/biodegradable composite yarns having at least two fibrous components and their conversion to medical devices, such as sutures and meshes, with modulated, integrated physicochemical and biological properties derived from the constituent yarns and which can be further modified to exhibit specific clinically desired properties.
[0004] A key feature of having an absorbable/biodegradable surgical implant comprising at least two differing fibrous components, which, in turn exhibit different absorption and strength retention profiles has been disclosed in the present parent application PCT Serial No. 2006014939. However, these applications did not describe any specifically new construct design of devices such as surgical sutures and hernial meshes, which are responsible for achieving novel clinical properties. Accordingly, this invention is directed to novel construct designs made of fully absorbable/biodegradable surgical sutures, especially those used in slow-healing tissues and surgical meshes such as those used in hernial repair and vaginal tissue reconstruction.
SUMMARY OF THE INVENTION
[0005] Generally, the present invention is directed to warp knitted composite meshes and braided composite sutures comprising slow-absorbable/biodegradable and fast-absorbable/biodegradable components, specially sized and constructed to produce surgical devices having unique properties.
[0006] One major aspect of this invention is directed to a warp-knitted composite mesh with a minimum area density of 50 g/m 2 , which includes (a) a slow absorbing/biodegradable multifilament yarn component having individual filament diameter of less than 20 micron; and (b) a fast-absorbing multifilament yarn component having individual filament diameter exceeding 20 micron, wherein the slow-absorbing/biodegradable multifilament component is a segmented copolymer made of molecular chains comprising at least 80 percent of l-lactide-based sequences and the fast-absorbing multifilament component is a segmented polyaxial copolymer made of molecular chains comprising at least 70 percent of glycolide-derived sequences, and wherein the slow-absorbing multifilament component is knitted in a 2-bar sand-fly net pattern and the fast-absorbing multifilament component is knitted in a standard 2-bar marquisette pattern, with all guide bars threaded 1-in and 1-out, using a warp knitting machine. Alternatively, the slow-absorbing multifilament component is knitted in 2-bar full tricot pattern and the fast-absorbing multifilament component yarn is knitted in a standard 2-bar marquisette pattern with all guide bars threaded 1-in and 1-out, using a warp knitting machine.
[0007] A clinically important aspect of this invention is the provision of a composite mesh having an area weight of about 130 g/m 2 and exhibiting a maximum burst force of at least 250 N and a maximum elongation of less than 10 percent under a 16 N force per cm of mesh width, and when incubated in buffered solution at pH 7.2 and 50° C. for about 2 weeks retains more than 20 percent of its maximum burst force and undergoes at least 12 percent elongation under a force of 16 N per cm of mesh width.
[0008] Alternatively, the slow-absorbing/biodegradable multifilament yarn component of the mesh comprises a poly-3-hydroxyalkanoate made of molecular chains consisting of at least 50 percent of 3-hydroxybutyric acid-derived sequences.
[0009] This invention also deals with a warp-knitted composite mesh with a minimum area density of 50 g/m 2 , comprising (a) a slow absorbing/biodegradable multifilament yarn component having individual filament diameter of less than 20 micron; and (b) a fast-absorbing multifilament yarn component having individual filament diameter exceeding 20 micron, wherein said mesh is coated with an absorbable polymer at a coating add-on of at least 0.1 percent based on the uncoated mesh weight. Optionally, the coating comprises a polyaxial copolyester made of molecular chains comprising about 95/5ε-caprolactone-/glycolide-derived sequences, wherein the coating contains at least 1 bioactive agent selected from those groups known for their antineoplastic, anti-inflammatory, antimicrobial, anesthetic and cell growth-promoting activities.
[0010] Another major aspect of this invention deals with a braided composite suture comprising (a) a slow-absorbing/biodegradable multifilament yarn component having individual filament diameter of less than 20 micron, and capable of retaining at least 20 percent of its initial breaking strength when tested individually as a braid and incubated in a phosphate buffer at pH 7.2 and 50° C. for about 2 weeks; and (b) a fast-absorbing/biodegradable multifilament yarn component capable of retaining at least 20 percent of its initial breaking strength when tested individually as a braid and incubated in a phosphate buffer at pH 7.2 and 50° C. for about 1 day. In one embodiment the slow-absorbing/biodegradable and fast-absorbing/biodegradable multifilament components constitute the core and sheath of the braid, respectively. Alternatively, the slow-absorbing/biodegradable and fast-absorbing/biodegradable multifilament components constitute the sheath and core of the braid, respectively.
[0011] In terms of the chemical composition of the composite suture, in one embodiment the slow-absorbing/biodegradable multifilament component comprises a segmented copolymer made of the molecular chains consisting of at least 80 percent of l-lactide-derived sequences and the fast-absorbing/biodegradable multifilament component comprises a segmented polyaxial copolymer made of molecular chains consisting of at least 70 percent of glycolide-derived sequences. Alternatively, the slow absorbable/biodegradable multifilament component comprises silk, or a poly-3-hydroxyalkanoate made of a molecular chain consisting of at least 50 percent of 3-hydroxybutyric acid-derived sequences.
[0012] Additional aspects of this invention deal with a braided composite suture as described above coated with an absorbable polymer at a coating add-on of at least 0.1 percent based on the uncoated suture weight. Optionally, the coating comprises a polyaxial copolyester made of molecular chains comprising about 95/5ε-caprolactone-/glycolide-derived sequences, wherein the coating contains at least one bioactive agent selected from those groups known for their antineoplastic, anti-inflammatory, antimicrobial, anesthetic and cell growth-promoting activities.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0013] During the first one to two days of introducing an implant in living tissue, an acute inflammation prevails at the implant site. This is manifested as redness, heat, swelling and pain. After about day three, any persistent local inflammatory response to the implant subsides. When a non-absorbable material is implanted, the acute inflammation persists for less than a week and the development of a fibrous connective tissue around the implant progresses for about a month, leading to a generally static, fibrous capsule. A long-term separation of the non-absorbable implant from surrounding tissues by the capsule can lead to complications. Depending on the type of implant site, these complications may (1) increase the risk of infection and (2) interfere with the integration of the implant components with surrounding tissue leading to mechanical instability, as in the case of hernial meshes. On the other hand, if the implant material biodegrades/absorbs over time, the inflammation can be restimulated, incrementally, during the implant residence time period at the site, a feature which can be most desirable in certain applications. These include surgical meshes used in hernial repair, where an incremental restimulation of inflammation can result in controlled and persistent collagen deposition and mechanical integration with the fibrous components of the mesh leading to critically needed mechanical stability. Obviously, one should not expect this to terminate after the first three or four weeks following implantation leading to catastrophic mechanical failure of the mesh. Additionally, the incremental restimulation of inflammation and controlled collagen deposition can be achieved through (1) movement of the mesh components and/or at the mesh-tissue interface; (2) providing continually increased porosity in the mesh to permit progressively increasing facile fibroblast migration; and (3) having structurally stable mesh construction that resists tear and unraveling under dynamic mechanical stresses. And, optimally, the mesh components should be designed to (I) exhibit at least two absorption/strength retention profiles, one that prevails during the first two to four weeks and a second which will be responsible for continued restimulation beyond four weeks; (2) display sufficient mechanical strength and stiffness in the first three to four weeks during which collagen is deposited and the mechanical load at the site commences to be shared between the mesh and surrounding tissue without experiencing premature deformation; (3) accommodate the biomechanical events associated with wound healing and tissue shrinkage, as well as incremental dynamic stresses due to regular motions of active patients, through an incremental increase in the engineering compliance of the mesh; and (4) have a carefully warp-knitted construction that accommodates mechanical changes at the implant site while resisting tearing and breaking/unraveling at the tissue-mesh interface and/or within the mesh construct itself.
[0014] In concert with the aforementioned discussion, the present invention addresses the requirements set forth for an optimal mesh. Similarly, it addresses the requirements of an optimum suture that is expected to provide an effective ligation for three to four weeks as well as up to a few months following implantation, as would be required for wound repairs of compromised and slow-healing tissues.
[0015] A key general aspect of this invention is directed to a warp-knitted composite mesh with minimum density of 50 g/m 2 to ensure having adequate mass and strength to allow anchoring to the natural tissue, using a suture and/or absorbable adhesive, without tearing, unraveling, and/or breaking immediately after placement and during the first few weeks of functional performance. This is to prevent mechanical failure at the tissue-mesh interface or within the mesh components. For anchoring the mesh to the biological site, an absorbable suture of choice will be expected to maintain a strength retention profile that parallels that of a long-lasting component of the composite mesh. Meanwhile, the composite mesh is expected to comprise (1) a slow-absorbing/biodegradable, multifilament yarn component having individual filament diameter of less than 20 micron and preferably less than 15 micron as the main, relatively more flexible matrix of the mesh, which retains a measurable breaking strength for at least six weeks and preferably for more than eight weeks; (2) a fast-absorbing/biodegradable, multifilament yarn component having individual filament diameter of more than 20 micron and preferably exceeding 25 micron, as the minor, relatively less flexible component of the mesh that will be responsible for providing adequate initial rigidity of the mesh, and facile anchoring to the surrounding tissues, while exhibiting a brief breaking strength profile of about two to four weeks—this is to allow the slow-absorbing flexible matrix to become progressively more extensible at about two to four weeks following implantation; and (3) a slow- and fast-absorbing multifilament components in specially designed warp-knitted construction to ensure their mechanical interdependence in terms of load-bearing contributions and ability to anchor to the surrounding tissue using an absorbable tissue adhesive, absorbable suture, or a combination, for example, of an absorbable cyanoacrylate-based adhesive and an absorbable suture—a useful illustration of such warp-knit construction entails knitting the slow-absorbing multifilament component in a 2-bar, sand-fly net pattern and the fast-absorbing component in a standard 2-bar marquisette pattern, with all guide bars threaded 1-in and 1-out in 18 gauge using preferably a Raschel or tricot knitting machine. An alternative composite mesh construction entails knitting the slow-absorbing component using a 2-bar full tricot pattern and the fast-absorbing component using a standard 2-bar marquisette pattern, with all guide bars threaded 1-in and 1-out in 18 gauge. The warp construction can be achieved using other patterns. To improve the initial burst strength of the composite mesh through minimizing the fiber-to-fiber friction coefficient and hence minimize the fraying of the mesh structure, a lubricant coating is applied to the mesh at a level of 0.1 to 10 percent based on the mesh uncoated weight. The absorbable coating can also be used as a carrier for the controlled release of one or more bioactive agents belonging to one or more group of drugs known for their antimicrobial, anti-adhesion, and growth-promoting agents. The ideal coating system can be a crystalline, easy-to-apply, lubricious polymeric system that provides surface lubricity and its composition can be controlled to assist in modulating the absorption/biodegradation profile of the fast-absorbing component at least in the first two weeks following implantation.
[0016] Although slow- and fast-absorbable/biodegradable components of the composite are, so far, described as multifilament yarns, which are warped independently, other alternative approaches can be used entailing (1) plying the fast- with the slow-absorbable/biodegradable yarns prior to warping; (2) using one or more additional yarns with a moderate or fast absorption/biodegradation profile; (3) using the fast-absorbing component as a single or two-ply monofilament; (4) using a yarn component based on an elastomeric polymer—this can be in the form of a fast-, moderate- or faster-absorbing monofilament, 2-ply monofilament or multifilament. The use of elastomeric components is expected to accommodate any transient change in stress at the application site at the initial period of implantation when inflammation-induced swelling is encountered. To further modulate the performance of the composite mesh, enzymatically biodegradable, multifilament yarn can be used as the slow-biodegrading component. Such yarns include those based on silk fibroin, poly-4-hydroxyalkanoate, casein, chitosan, soy protein, and similar naturally derived materials with or without chemical modification to modulate their biodegradation and breaking strength retention profiles.
[0017] Another key general aspect of this invention is directed to a braided suture comprising at least two absorbable/biodegradable monofilament and/or multifilament yarn components having a range of absorption/biodegradation and breaking strength retention profiles. The rationale for invoking such a diversity in the components constituting the composite braid is practically similar to that noted above for composite mesh, with the exception of the fact that in constructing the braid, there is an additional degree of freedom, namely, having a core and sheath as the basic structural components of the braid. Meanwhile, the braid construction may entail (1) using variable ratios of the core-to-sheath without encountering core popping; (2) having slow-absorbable/biodegradable, multifilament yarn as the core or sheath with the balance of braid consisting of a fast-absorbable/biodegradable multifilament yarn; (3) using elastomeric monofilament, plied monofilament or multifilament yarn as part of the braid construct and preferably in the core at variable levels to impart a controlled level of elasticity—this is to accommodate site swelling during the first few days following suture implantation. The composite suture can be coated to (1) improve its tie-down and handling properties; (2) possibly prolong the breaking strength retention profile; and (3) function as an absorbable carrier for the controlled release of one or more bioagent selected from the groups known for their antimicrobial, anti-adhesion, antithrombogenic, antiproliferative, antineoplastic, anti-inflammatory, and cell growth-promoting activities. The coating can also be used to allow the controlled and timely delivery of anesthetic agents to mediate pains following surgery. A useful feature of using a coating with an antineoplastic agent allows the use of the composite suture in cancer patients to minimize the likelihood of metastasis. Another useful feature is the use of the composite suture in anchoring synthetic vascular graft and perivascular wrap where (1) having two or more absorption/biodegradation profiles can allow accommodating physicomechanical changes at the suture line due to prevailing biological events; and (2) using antithrombogenic and/or antiproliferative agents can be beneficial in maintaining the long-term patency of the graft.
[0018] A clinically important aspect of this invention deals with bioactive meshes comprising a coating containing an antineoplastic, anti-inflammatory, and/or antiproliferative agent that allows the use of the composite mesh as vascular wrap in the management of vascular embolism.
[0019] Further illustrations of the present invention are provided by the following examples:
Example 1
Preparation of Yarns I and II for Composite Mesh Construction
[0020] A segmented l-lactide copolymer (P1) prepared by the copolymerization of a mixture of an 88/12 (molar) l-lactide/trimethylene carbonate [following the general polymerization methods described in U.S. Pat. No. 6,342,065 (2002)] was melt-spun using a 20-hole die to produce multifilament Yarn I—this is used as the slow-absorbable/biodegradable component of certain composite meshes. The extruded multifilament yarn was further oriented using a one-stage drawing over a heated Godet at about 100-120° C. prior to its use for knitted mesh construction. Typical properties of Yarn I are shown below. For producing Yarn II, the fast-absorbing/biodegradable component of the composite mesh, a polyaxial, segmented glycolide copolymer (P2), made by ring-opening polymerization of a combination of an 88/7/5 (weight) glycolide/trimethylene carbonate/l-lactide [using the general polymerization method described in U.S. Pat. No. 7,129,319 (2006)] was melt-spun using a 10-hole die and oriented by in-line drawing. Typical properties of Yarn II and the form used in knitting are shown below.
[0021] Key Properties of Yarns I and II:
[0022] Yarn I (2-Ply Natural Yarn)
Fiber Count: 43 Denier Range: 80-100 g/9000 m Tenacity Range: 1.8 to 4.5 g/denier Ultimate Elongation: 20-30%
[0027] Yarn II (1-Ply Natural Yarn)
Fiber Count: 10 Denier Range: 120-170 g/9000 m Tenacity Range: 3.5-5.5 g/denier Ultimate Elongation: 40-70%
Example 2
General Method for Composite Mesh Construction
[0032] Compositions consisting of Yarns I and II which possess different degradation profiles (one relatively fast degrading and one slow degrading) were constructed using various knitting patterns to construct the desired warp-knitted meshes. Knit constructions were produced using a two-step process of warping yarn onto beams and constructing meshes using a typical Raschel or tricot knitting machine. Various knitting patterns and weight ratios of I to II can and were varied to modulate mechanical properties of the specific mesh. Knit constructions can be made from multifilament yarn, monofilament yarn, or combinations thereof. Knit mesh was heat set or annealed at 120° C. for 1 hour while under constant strain in the wale and course directions. Coating can be applied following annealing to modify the in vivo and/or in vitro characteristics.
Example 3
Knitting Process of Mesh Pattern A
[0033] The knitting process utilized two warped beams of Yarn I, threaded on bars 1 and 2, and two warped beams of Yarn II threaded on bars 3 and 4. The knitting machine was equipped with 18-gauge needles. Yarn II was knitted in a 2-bar marquisette pattern and Yarn I was knitted in a 2-bar sand-fly net pattern with all guide bars for each pattern threaded 1-in and 1-out in 18 gauge.
[0034] Pattern a (28 Courses Per Inch)
[0035] Bar 1—1-0/1-2/2-3/2-1//2x (1-in, 1-out)
[0036] Bar 2—2-3/2-1/1-0/1-2//2x (1-in, 1-out)
[0037] Bar 3—1-0/0-1/14x (1-in, 1-out)
[0038] Bar 4—0-0/3-3//4x (1-in, 1-out)
Example 4
Knitting Process of Mesh Pattern-B
[0039] The knitting process utilized two warped beams of Yarn I threaded on bars 1 and 2 and two warped beams of Yarn II, threaded on bars 3 and 4. The knitting machine was equipped with 18-gauge needles. Yarn II was knitted in a 2-bar marquisette pattern and Yarn I was knitted in a 2-bar full tricot pattern with all guide bars for each pattern threaded 1-in and 1-out in 18 gauge.
[0040] Pattern B (19 Courses Per Inch)
[0041] Bar 1—1-0/2-3//4x (1-in, 1-out)
[0042] Bar 2—2-3/1-0//4x (1-in, 1-out)
[0043] Bar 3—1-0/0-1//4x (1-in, 1-out)
[0044] Bar 4—0-0/3-3//4x (1-in, 1-out)
Example 5
Characterization and In Vitro Evaluation of Typical Composite Meshes from Example 3
[0045] Testing Methods for Meshes from Example 3
[0046] Mechanical properties were characterized using the ball burst testing apparatus with physical characteristics based on the ASTM D3787-01 guideline for the fixture geometry (25.4 mm polished steel ball, 44.45 mm diameter inside opening). The mesh was clamped in the fixture without any applied tension and the ball was positioned in the center of the 44.45 mm diameter opening. The ball is then brought down to a position on the mesh such that a 0.1N force is applied. The test is initiated and the ball travels at 2.54 cm/min until failure characterized by the point of maximum load. For each test the following three characteristics were recorded with standard deviation values for n=4 sample sizes:
[0000] 1) Maximum burst force obtained during the test (N)
2) The extension at the maximum load (mm)
3) The extension at 71N load (mm)
[0047] The extension at 71N is used to determine the 16N/cm elongation. The value of 71N is derived from the diameter of the opening (4.445 cm×16N/cm=71N). Initially the mesh has a 44.45 mm diameter and is all in one plane. As the test progresses the ball pushes the mesh downward and creates a cone like shape with the radius of the ball as the tip. Using CAD and curve fitting software a mathematical expression which relates the linear travel of the ball to the change in length of a line that passes under the center of the ball and up to the original 44.45 mm diameter (radial distension) was developed. From this information the percent elongation was determined
[0048] In vitro conditioned burst strength retention [BSR=(max. load at time point/initial max. load)*100] was conducted using a MTS MiniBionix Universal Tester (model 858) equipped with a burst test apparatus as detailed in ASTM D3787-01. Samples were tested initially, after in vitro conditioning using a 0.1M solution of buffered sodium phosphate at a 12.0 pH in 50 mL tubes for 10 days, and after conditioning using a 0.1M solution of buffered sodium phosphate at a 7.2 pH in 50 mL tubes for multiple time points of interest. Tubes were placed in racks and incubated at 50° C. under constant orbital-agitation. Samples were removed at predetermined time points for mechanical properties testing (n=3).
[0000] Physical Properties of a Typical Warp-Knit Composite Mesh from Example 3
[0000] TABLE I Pattern A Warp Knit Composite Mesh Physical Properties Knitting Area Weight Yarn II Content Pattern (g/m 2 ) (weight %) Pattern A 132 40
Mechanical Properties of Meshes from Example 3
[0000]
TABLE II
Pattern-A Warp Knit Composite Mesh Initial Burst Properties
Elongation
Elongation
Sample
Max. Burst
at Max
at 71 N
Elongation at
Description
Force (N)
Force (mm)
Force (mm)
16 N/cm (%)
Pattern A
356
14.6
6.8
5.2
[0000]
TABLE III
Properties of Pattern A Warp Knit Composite Mesh Following
Accelerated In Vitro Conditioning (12 pH, 50° C., 10 days)
Elongation
Elongation
Sample
Max. Burst
at Max
at 71 N
Elongation at
Description
Force (N)
Force (mm)
Force (mm)
16 N/cm (%)
Pattern A
194
21.5
15.8
25.6
[0000]
TABLE IV
Properties of Pattern A Warp Knit Composite Mesh Due to Accelerated
In Vitro Aging (7.2 pH, 50° C.)
Max.
Burst
Elongation at
Elongation at
Elongation at
In Vitro
BSR
Force
Max Force
71 N Force
16 N/cm Force
Duration
(%)
(N)
(mm)
(mm)
(%)
0 days
—
352
14.29
6.52
4.76
3 days
106.3
374
14.71
6.84
5.28
7 days
44.9
158
14.24
7.92
7.14
11 days
59.1
208
18.89
13.13
18.38
14 days
55.7
196
19.63
14.31
21.46
18 days
52.6
185
17.98
13.20
18.56
21 days
55.4
195
18.44
13.21
18.59
35 days
51.4
181
17.88
13.54
19.43
56 days
36.9
130
16.37
14.01
20.66
Example 6
Characterization and In Vitro Evaluation of Typical Composite Meshes from Example 4
[0049] Testing Methods for Meshes from Example 4
[0050] Mechanical properties testing was conducted using a MTS MiniBionix Universal Tester (model 858) equipped with a burst test apparatus as detailed in ASTM Q3787-01. Samples were tested initially and after being conditioned using a 0.1M solution of buffered sodium phosphate at a 12.0 pH in 50 mL tubes for 10 days. Tubes were placed in racks and incubated at 50° C. under constant orbital-agitation. Samples were removed at predetermined time points for mechanical properties testing (n=3).
[0000] Physical Properties of a Typical Warp-Knit Composite Mesh from Example 4
[0000] TABLE V Pattern B Warp Knit Composite Mesh Tabulated Physical Properties Knitting Yarn B Content Pattern Area Weight (g/m 2 ) (weight %) Pattern B 135 31
Mesh Resultant Mechanical Properties from Example 4
[0000]
TABLE VI
Pattern B Warp Knit Composite Mesh Initial Burst Properties
Elongation
Elongation
Sample
Max. Burst
at Max
at 71 N
Elongation at
Description
Force (N)
Force (mm)
Force (mm)
16 N/cm (%)
Pattern B
436
16.3
7.1
5.7
[0000]
TABLE VII
Properties of Pattern B Warp Knit Composite Mesh Following
Accelerated In Vitro Conditioning (12 pH, 50° C., 10 days)
Elongation
Elongation
Sample
Max. Burst
at Max
at 71 N
Elongation at
Description
Force (N)
Force (mm)
Force (mm)
16 N/cm (%)
Pattern B
240
19.4
13.2
18.5
Example 7
Preparation of Yarn III for Composite Braid Construction
[0051] The same polymer precursor, P2, described in Example 1 was used in preparing multifilament Yarn III. The polymer was melt-spun using a 20-hole die to produce multifilament Yarn III, which was further oriented using one-stage drawing over a heated Godet at about 100-120° C., prior to its use in braid construction.
Example 8
Construction of Composite Braid SM1-1 Comprising a Yarn I-Core and Yarn III-Sheath
[0052] Braid SM1-1 was prepared using a 4-carrier core of Yarn I as single ply and 8-carrier Yarn III as 3-ply. The braid was hot-stretched to about 5-10 percent of its initial length using heated air at about 90° C. to tighten the braid construction. The strained braid was then annealed at 110° C. for 1 hour to yield a braided suture having about 110 ppi and a diameter of about 0.35 mm.
Example 9
Construction of Composite Braid SM1-2 Comprising a Yarn III-Core and Yarn I-Sheath
[0053] Braid SM1-2 was prepared using a 6-carrier core of Yarn III as single ply and 16-carrier sheath of Yarn I as single ply. The braid was hot stretched and annealed as described in Example 8 to yield a braided suture having about 50 ppi and a diameter of about 0.36.
Example 10
In Vitro and In Vivo Evaluation of Braids SM1-1 and SM1-2 Suture Properties
[0054] The braids were sterilized with ethylene oxides and tested for their (1) initial physical properties; (2) accelerated in vitro breaking strength retention profile at pH 7.2 and 50° C.; and (3) in vivo breaking strength retention using a subcutaneous rat model. The results of the in vitro and in vivo evaluation are summarized in Table VIII.
[0000]
TABLE VIII
In Vitro and In Vivo Properties of Composite Braids SMI-1 and SMI-2
Experiment
Braid SMI-1
Braid SMI-2
Physical Properties:
Diameter, mm
0.35
0.36
Initial Strength, Kpsi (N)
54.4 (36.1)
52.4 (36.7)
Elongation, %
45
41
Knot Max. Load, N
24.7
23.7
In vitro Breaking Strength Retention (BSR)
at pH 7.2/50° C. Percent at
Days 1, 2, and 3
85, 50, 24
81, 80, —
Weeks 1 and 2
21, 19
76, 76
In-Vivo BSR at Percent at Weeks 2 and 3
43, 25
81, 77
[0055] Preferred embodiments of the invention have been described using specific terms and devices. The words and terms used are for illustrative purposes only. The words and terms are words and terms of description, rather than of limitation. It is to be understood that changes and variations may be made by those of ordinary skill art without departing from the spirit or scope of the invention, which is set forth in the following claims. In addition it should be understood that aspects of the various embodiments may be interchanged in whole or in part. Therefore, the spirit and scope of the appended claims should not be limited to descriptions and examples herein. | Absorbable composite medical devices such as surgical meshes and braided sutures, which display two or more absorption/biodegradation and breaking strength retention profiles and exhibit unique properties in different clinical settings, are made using combinations of at least two types of yarns having distinctly different physicochemical and biological properties and incorporate in the subject construct special designs to provide a range of unique properties as clinically useful implants. | 3 |
BACKGROUND
1. The Field of the Invention
The invention pertains to the field of continuous positive airway pressure apparatus and methods and more particularly to portable systems for active adult users during travel.
2. The Background Art
Continuous positive airway pressure (CPAP) therapy is often used to treat obstructive sleep apnea as well as certain other disorders. In a CPAP apparatus and method, pressurized air is delivered through a mask to a patient's airway. Air may be introduced through the nostrils or through a mask that covers the nostrils and mouth. Typically, such systems are set on a night stand or other support beside a bed, and operate from wall current or a battery power source. Typically, a fan in a “generator” blows ambient air to create a pressurized supply having a pressure of from about five to fifteen centimeters of water. The mask or interface portion of the apparatus may be oral, oral-nasal, or simply nasal in its introduction of air.
Typically, such systems are treated as a medical devices and are engineered to be efficient movers of air through the various passages. Accordingly, such devices typically have a very box-like aspect ratio in which the height, width, and the depth (or thickness, width and length), are typically sized to be of the same order of magnitude. Thus, the aspect ratio is approximately one to one to one (1:1:1). In the prior art, many such systems have aesthetically pleasing lines developed to make the device seem less rectangular or box-like, yet the overall principal dimensions are about the same.
One of the particular difficulties is the unwieldy size and shape of CPAP systems during travel. Accordingly, each requires a large fraction of the space within a person's luggage. Even supposedly compact or portable CPAP units, when ultimately designed, still have sufficient bulk in all three dimensions as to require a packing system that requires either another piece of luggage or a sizeable portion of the space in other large luggage.
What is needed is an apparatus that can meet several criteria for traveling. The apparatus should fit within luggage configured to hold a laptop computer. If a CPAP system were configured to take on more of the aspect ratios of a laptop computer, then it could be carried as part of carry-on luggage, could be opened for inspection, and could be readily evaluated by conventional security mechanisms in airports. Thus, traveling professionals would not be required to carry such large luggage, or an additional piece of luggage, especially checked luggage, specifically to accommodate the CPAP system.
BRIEF SUMMARY OF THE INVENTION
In view of the foregoing, in accordance with the invention as embodied and broadly described herein, a method and apparatus are disclosed in one embodiment of the present invention as including a housing sized and shaped to fit the space requirements and power requirements typical of a lap top computer.
In accordance with certain embodiments of an apparatus and method in accordance with the invention, a CPAP unit may include a housing, sized and shaped to fit in luggage designed to accommodate conventional laptop computers and their supporting peripherals. The system may typically include a drive system for generating a pressurized air stream at a volume and pressure in accordance with the therapy for which CPAP systems are designed. Likewise, an apparatus and method may include a delivery system of fittings, tubing (hose), and masks in order to deliver the pressurized stream of air into the breathing system of a user.
In certain embodiments, an apparatus in accordance with invention may include various electrical and electronic control systems in order to turn the machine on and off, control the air flow rate or motor speed, and the like. Other systems may be incorporated to accommodate the valving of air flows to and from the lungs of a user. That is, any of the valving systems whereby air may be relieved or expelled from a mask or the delivery system, or the like may be incorporated in a system in accordance with the invention.
The power system may rely on wall power, converted DC power from a wall outlet through a DC power supply, a battery, a computer battery, or the like.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing features of the present invention will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only typical embodiments of the invention and are, therefore, not to be considered limiting of its scope, the invention will be described with additional specificity and detail through use of the accompanying drawings in which:
FIG. 1 is a perspective view of one embodiment of an apparatus in accordance with the invention, in which tubing or a delivery hose for the pressurized air supply may be stowed in a spooled configuration within the housing of the apparatus;
FIG. 2 is a perspective view of one embodiment of the spool center and the fan system of the apparatus of figure one, having the lid and upper console portions removed;
FIG. 3 is a perspective view of one embodiment of the apparatus of FIG. 1 in a closed configuration with the tubing stowed therein;
FIG. 4 is perspective view of an alternative embodiment of an apparatus in which a cavity is available to stow the tubing and mask completely within an outer case, to be not visible when the case is closed;
FIG. 5 is a perspective view of the apparatus of FIG. 4 illustrating the stowed mask and tubing with associated fittings;
FIG. 6 is a perspective view of one embodiment of a motor and fan system suitable for implementation in an apparatus in accordance with the invention;
FIG. 7 is perspective view of an alternative embodiment of a fan and motor system suitable for pressurizing air in an apparatus in accordance with the invention;
FIG. 8 is a perspective view of an alternative embodiment of a fan suitable for developing a flow of pressurized air in an apparatus in accordance with the invention;
FIG. 9 is a perspective view of an alternative embodiment of a fan, designed to provide an axial flow of pressurized air in an apparatus in accordance with the invention;
FIG. 10 is a perspective view of an alternative embodiment of an apparatus in accordance with the invention, having a capability to expand a plenum for development of a larger supply of pressurized air;
FIG. 11 is a perspective view of the apparatus of FIG. 10 with the tubing removed from the case for deployment;
FIG. 12 is a perspective view of the apparatus of FIGS. 10 and 11 illustrating the position of the aperture and connector feeding the tubing and mask of the apparatus from the lid side of the plenum chamber;
FIG. 13 is a perspective view of one embodiment of a power supply suitable for powering an apparatus in accordance with the invention;
FIG. 14 is a perspective view of an alternative embodiment of a power supply suitable for portability and for powering the apparatus in accordance with the invention;
FIG. 15 is a perspective view of one alternative embodiment of a rechargeable battery suitable for use to power an apparatus in accordance with the invention, or suitable for recharging a computer battery for use in both a laptop computer and a CPAP system in accordance with the invention;
FIG. 16 is a perspective view of one embodiment of a carrying case suitable for packing an apparatus in accordance with the invention;
FIG. 17 is a perspective view of an alternative embodiment of a luggage system accommodating an apparatus in accordance with the invention; and
FIG. 18 is a perspective view of yet another alternative embodiment of a carrying case suitable for packing an apparatus in accordance with the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1 , in one embodiment of an apparatus and method in accordance with the invention, a system 10 or device 10 may be configured to provide a continuous positive airway pressure to a user. In the illustrated embodiment, a housing 12 may contain the basic elements required to drive the air to an elevated pressure. In typical usage, a fraction of a pound per square inch or a fraction of a kilogram per square centimeter will be provided by the system 10 , to the airway of a user.
Typically, a drive system 14 provides the prime mover of air. The drive system 14 may draw air from the environment, through a filter, or without a filter, and pressurize it sufficiently to maintain a positive pressure against which a user breathes during sleep. From the drive system 14 , a delivery system 16 provides passageways to carry the air to an interface for delivery into the nostrils or mouth of a user, or both.
Typically, a control system 18 may be designed to be as simple or sophisticated as desired for the appropriate therapy. At a rudimentary level the system may be turned off and on. In a more sophisticated embodiment, a selection of the pressure, the net air flow, the profile of the increase of pressure of the air flow, or the like may be controlled in order to provide for the comfort and therapy of a user.
A power system 20 provides a power source to drive the drive system 14 . In certain embodiments, a pneumatic power system may be provided. A convenient power system may rely on either wall current or battery power instead. To provide completely self-contained power, a power system 20 may be as simple as a rechargeable battery built into the system 10 . Alternatively, a power supply that connects to a wall outlet may service the system equally well. In yet another alternative embodiment, both may be provided in order that a system may be recharged when the wall current is available, but may still be used when wall current is not available.
Referring to FIG. 1 , the system 10 may include a base 22 to which to mount the other components of the system 10 . A console 23 may be provided in order to accommodate controls, user interface, and other access to the system during operation. The console 24 or console layer 24 may be positioned opposite the base 22 , each effectively forming a flange of a spool. Thus, the base 22 and console 24 may actually act as flanges of a spool to receive therebetween the delivery system 16 .
In certain embodiments, whether for protection, or simply for purposes of convenience, securement, or closing a display of information or the like, a cover 26 may be provided to close the console layer 24 .
In certain embodiments the drive system 14 may be protected by a grid 28 in order to prevent entry of fingers or other small objects into the drive system 14 .
Downstream from the drive system 14 an aperture 30 may be provided to discharge air from the drive system into the delivery system 16 . A fitting 31 may be provided about the aperture 30 in order to accommodate connection and disconnection of the delivery system 16 .
In certain embodiments, storage space 32 may be provided for a mask 34 or interface 34 . The storage space 32 may be formed as a recess in the console 24 of the apparatus. In other embodiments the recess 32 may be dispensed with in order to simply store the mask elsewhere. Soft masks may be folded up or otherwise placed in a small space. In certain embodiments, it is desired that the mask 34 be of a substantially stiffer quality, in order to assure a firm seal against the face. Thus, a mask 34 may need storage space 32 within the apparatus 10 .
A storage space 36 for a power supply 38 may be provided in the console 24 as well. In the illustrated embodiment, a simple DC power supply 38 may provide the conversion of wall power (alternating current) to be converted to direct current to drive the drive system 14 .
A recess 40 or space 40 may be provided between the base 22 and console 24 in order to wrap a hose 42 or tube there around. The hose 42 may be formed in any suitable manner. A convoluted hose may actually provide a very flexible, light, and still comparatively compact system for delivering air from the apparatus 10 to a user. In particular, the hose 42 will connect to the fitting 31 of the aperture 30 to receive air driven by the fan 50 .
The fan 50 may be protected by the grid 28 at the inlet where air is received. Accordingly, the fan 50 may blow air to a higher pressure and discharge it through the aperture 30 into the hose 42 for delivery to a mask 34 and ultimately to a user.
In certain embodiments, a cord 52 may deliver power from a power supply or wall current into a plug 54 . The plug 54 may fit into a jack 55 formed within the base 22 , console 24 , or other part of the housing 12 in order to access the drive system 14 and power it. In embodiments where an internal battery is powering the apparatus 10 , the cord 52 and plug 54 may simply operate to power the battery during recharging.
In certain embodiments, various buttons 56 or switches 56 may be provided for the system 10 . In the illustrated embodiment, various buttons 56 a , 56 b , 56 c , 56 d are shown. For example, a button 56 a may be a switch to turn the drive system 14 on and off. Other buttons 56 c , 56 d may control the increase and decrease of the speed of the fan 50 .
Other buttons 56 d may control other factors, including the display 60 . A display 60 may include instructions, may provide feedback information regarding pressure, fan speed, or the like, and may include interactive selections for controlling the apparatus 10 by the user. In general, information and instructions by way of warning and basic set up may also be included in a label 58 simply printed and adhered to a portion of the apparatus 10 .
In the illustrated embodiment, deployment of the apparatus 10 may include unwrapping the delivery system 16 including the hose 42 with its fittings 44 , 46 from the apparatus 10 , such as from a spooled location between the console layer 24 and the base layer 22 acting as flanges of a spool. Accordingly, the fitting 44 may be connected to the output fitting 31 , and the fitting 46 to the mask 34 . A mask 34 may be formed in any suitable manner, typically of a flexible material in contact with the skin in order to form a good seal, with straps or other secure mechanisms to secure it to the face of a user. The mask 34 may cover only the nostrils, the nostrils and the mouth, or only the mouth. Accordingly, the drive system 14 , and the fan 50 in particular, provides pressurized air through the aperture 30 into the tubing 42 for delivery into the mask 34 at an increased pressure above ambient pressure.
Meanwhile, the power supply 38 may be removed from its storage location 36 and plugged into outlet power in order feed the cord 52 and the plug 54 connected to power the motor driving the fan 50 .
Upon waking, a user may stow the system 10 by removing the fitting 44 from the aperture 30 with its retaining fitting 31 and removing the mask 34 , optionally, from the mask fitting 46 . In some embodiments, a more compact system may have a foldable or very flexible mask 34 . The mask fitting 46 may also be formed integrally between the tubing 42 and the mask 34 making removal of the mask 34 from the tubing 42 unnecessary. Likewise, the fitting 31 , 44 need not be readily separable, nor separable at all, nor distinct from one another.
In either mode, the tubing 42 , whether or not removed from the fitting 31 or mask 34 may be spooled around the space 40 between the base 22 and console 24 to stow it. Detents may be provided by way of bosses, tabs, or simply a closer proximity to one another of the edges of the base 22 and console 24 in order to retain the tubing 42 therebetween. After final stowage of the power supply 38 in its storage location 36 , the lid 26 or cover 26 may be closed on hinges 48 against the console 24 in order to close the system up for travel.
Referring to FIG. 2 , a view of the apparatus 10 of FIG. 1 is illustrated showing only the base 22 with selected components located below the console 24 . In the illustration, a spool portion 62 or mandrel 62 for receiving the tubing 42 may be located between the base 22 and the console 24 . Within the periphery of this spool portion 62 , or mandrel 62 , the fan 50 may operate.
In the illustrated embodiment, the fan 70 represents a generic fan 50 of FIG. 1 . In the illustrated embodiment, the fan 70 is a squirrel-cage type fan and the motor 68 is embedded within the confines of the fan 70 . A shroud 64 surrounds the fan 70 to direct the air to an output duct 66 .
The spinning of the fan 70 about the motor 68 (by the motor 68 ) causes the air to move radially away from the fan 70 , while also moving the air circumferentially with respect to the outer circumference of the fan 70 . Accordingly, the duct 66 is filled with pressurized air, while the region within the circumference of the fan 70 is decreasing in pressure as it draws air through the grid 28 and through the fan 70 .
Referring to FIG. 3 , the apparatus 10 in the illustrated embodiment may fold up with the cover 26 against the console 24 , forming a compact package between the base 22 and the cover 26 . Meanwhile, the hose 42 or tubing 42 is spooled around the mandrel 62 in order to fit within the overall envelope defined by the juxtaposed base 22 and cover 26 .
Referring to FIG. 4 , an apparatus 10 may have a housing 12 formed of a base 22 and a cover 26 . The base 22 and cover 26 may be connected by a hinge 48 pivotable between a closed and an open position. In FIG. 4 , the apparatus 10 is shown in an open position with the tubing 42 removed from stowage along with the power supply 38 for use. In the illustrated embodiment, the delivery system 16 is constituted by the tubing 42 with its associated fittings 44 , 46 and mask 34 , having a strap 35 for securement to the face of a user.
Meanwhile, the drive system 14 is enclosed within a shroud 64 and the fan 50 is behind the grid 28 provided for protection. The aperture 30 is connectable to the fitting 44 to direct pressurized air from the duct 66 provided as an outlet from the shroud 64 delivering pressurized air from the fan 50 into the tubing 42 . In the illustrated embodiment, the control buttons 56 may be provided on the case 12 or housing 12 in any suitable location. In the illustration, the control buttons 56 are positioned on the base 22 . Likewise, the jack 55 for receiving the plug 54 from the power supply 38 and cord 52 is located on the front face of the base 22 .
Accordingly, the power can be converted from wall power to DC current by the power supply 38 and delivered through the plug 54 and jack 55 to the motor 50 inside the shroud 64 . Controls 56 may be used for controlling on, off, pressure, power, speed, or the like. The display 60 may provide instructions for monitoring of the operation of the apparatus 10 .
Referring to FIG. 5 , the apparatus 10 of FIG. 4 may be placed in a stowed configuration by wrapping the tubing 42 about the drive system 14 containing the fan 50 and shroud 64 . The fitting 44 may be disconnected from the aperture 30 or remain in it. Likewise, the fitting 46 may be removed from the mask 34 or remain connected. The mask 34 in the illustrated embodiment may be stowed within the base 22 just as the tubing 42 or hose 42 . Thus, closure of the lid 26 or cover 26 against the base 12 provides an envelope that is approximately that of a laptop computer and encloses the accompanying supporting peripheral elements of the apparatus 10 in a compact and easily transportable unit. Various types of sealing mechanisms such as bosses, knobs, ridges or other detents within the hinge 48 , or between the cover 26 and base 22 may be implemented in accordance with principles or devices known in the art.
Referring to FIG. 6 , an apparatus 10 in accordance with the invention may include a fan 50 connected directly to a motor 68 , or connected indirectly as illustrated. In the illustrated embodiment of FIG. 6 the motor 68 is connected to the fan 50 by a set of pulleys 74 , 76 and corresponding shafts 75 , 77 . A belt 72 connects the pulleys 74 , 76 in order to drive the fan shaft 77 from the motor shaft 75 .
In the illustrated embodiment, the axial direction 80 represents the direction of intake, while the radial directions 82 represent the direction that air moves in response the spinning of the fan 50 . A shroud 64 around the fan 50 may restrict the flow of air and directly into a particular duct 66 as described hereinabove. In response to the rotation of the fan, the space in the center of the fan 50 is evacuated or rather contains air at reduced pressure, while the area around the circumference of the fan represents air being driven in a radial 82 and a circumferential 84 direction. The shrouding 64 prevents air from escaping the fan 50 , while the ducting 66 provides a location or plenum for the air to accumulate at elevated pressure in order to be driven out the aperture 30 to the tubing 42 .
Referring to FIG. 7 , in an alternative embodiment, a motor 68 may be embedded within the fan 50 in order to reduce the overall size of the system 10 . However, if the fan 50 is formed to be of a comparatively thin profile, then the motor may need additional space. Meanwhile, the vanes 78 tend to drive the air in a circumferential direction 84 , resulting in acceleration in a radial direction 82 . As the air escapes from the vanes 78 or blades 78 of the fan 50 , it may have both a circumferential 84 and a radial 82 component of velocity. Accordingly, it may be ducted as described hereinabove.
In typical embodiments, the fan 50 may be formed of vanes 78 projecting (for example, at right angles) from a disk 79 or base 79 . Typically, the base 79 will include a hub for receiving a shaft 77 on the motor 68 . Any suitable attachment mechanism including keys, set-screws, friction, splines, and the like may be used to secure the shaft 77 to the fan 50 .
Referring to FIG. 8 , in one embodiment of an apparatus 10 in accordance with invention, the fan 50 may actually be configured with vanes that taper toward the center hub 86 , having their greatest height from the frame 79 or disk 79 near the outer periphery thereof. Accordingly, the vane 78 may actually act as trapezoidal or triangular vanes that are very short axially with respect to the disk 79 near the hub 86 , and very tall near the outer periphery of the disk 79 .
Thus, the air flow in 88 will be drawn in an axial direction into the fan while the blades 78 or vanes 78 rotate, the air moves in a circumferential direction 84 . A response of the air is to flow outwardly in a radial direction 82 such as the flow illustrated as flow 90 b . Ultimately, however, the shroud 64 and duct 66 will permit escape of the air only in a circumferential direction 84 illustrated as the airflow 90 a exiting the fan 50 .
The squirrel cage fan of 57 , and the vane fan of FIG. 8 both tend to be centripetal or centrifugal fans. That is, the pressure comes as a result of the spinning of the air, and its tendency to want to escape radially 82 from the circumferential motion 84 . That is, any motion in a circumferential direction 84 is actually an acceleration toward the center shaft 77 , and the air preferentially migrates radially 82 .
Referring to FIG. 9 , another embodiment of the fan 50 may include a shaft 77 and hub 86 from which various vanes 78 extend outward. In the embodiment of FIG. 9 , air is actually inducted from one side of the fan 50 in an axial direction 80 , and is discharged out the other side in the same axial direction 80 . Of course, in the illustrated embodiment, the direction of rotation in the circumferential direction 84 determines which direction or sense the air flow will actually take in the axial direction 80 .
One of the advantages of a squirrel cage fan 50 or a vane fan 50 is a comparatively thin profile on the order of from about one half inch to about an inch and a half, or perhaps up to two inches. On a substantially larger radius of from about one and half to about four inches, the fan may provide a comparatively large flow rate (e.g. 0.1 to about 2 cfm), large pressure increase (e.g. 5 to 30 cm of water), or the like, into a comparatively smaller duct, such as the duct 66 , and the tube 42 . One benefit of the fan 50 illustrated in FIG. 9 is that a comparatively quite fan with a minimal direction change may be implemented. Many pancake fans 50 may actually include a motor within the hub 86 in the fan 50 of FIG. 9 , thus forming a comparatively compact, axial drive system 14 .
Referring to FIG. 10 , an apparatus 10 may include a housing 12 having a base 22 , console 24 , and cover 26 . Likewise, a drive system 16 may include a fan 50 under a grid 28 to drive airflow into a tube 42 . In the illustrated embodiments, the console portion 24 actually becomes the bottom of the housing 12 , when stowed. Nevertheless, the control buttons 56 may be provided on a panel 92 associated with the console layer 24 of the apparatus 10 . Likewise, some type of power line 52 with its associated plug 54 may provide power into the system by any of the mechanisms discussed above or known in the art. Meanwhile, the mask 34 may be stowed with the tubing 42 and its associated fittings 44 , 46 within the space available in the base 22 .
In the illustrated embodiment of FIGS. 10-12 , retainers 94 may provide flexible or rigid restraints in order to hold the tubing 42 in place during stowage. In one embodiment, the retainers 94 may be formed of a flexible plastic or stiff rubber such that they may be easily deflected in order to place the tubing behind them. The retainers 94 may be replaced by belts, straps, or the like, securing to the base 22 in certain embodiments.
By either means, the tubing 42 may be wrapped for stowage within the base 26 . Meanwhile, the grid 28 covering the fan 50 may cover a squirrel cage fan 50 , a vane fan 50 , an axial fan 50 , or any other suitable mechanism. In the illustrated embodiment, an optional bellows 96 is included. The bellows provides an expansion space between the base 22 and the lid 26 in order to provide a plenum or expanse of space or volume in which a volume of air under pressure can be collected.
The value of a plenum is that pressures are moderated somewhat in response to the breathing of an individual, or changes in output. For example, whenever an individual is breathing against the pressure of air within the tubing 42 , pressure rises behind the fan 50 . This effect may be somewhat ameliorated by providing a plenum that tends to have sufficient volume to absorb the instantaneous fluctuations in pressure and volume of air.
Any suitable support including the bellows alone, or flexible joints, struts, or the like may be used to support the cover 26 with respect to the base 22 . In such an embodiment, the system may actually expand to a larger size than its stowed size in order to create a plenum within the bellows 96 and the lid 26 .
Referring to FIG. 12 , the apparatus of FIGS. 10 and 11 is illustrated in a stowed configuration. For clarity, the hose 42 has been removed from the housing 12 in order to illustrate an embodiment of how the fitting 44 may fit onto the cover 26 in the aperture 30 . When the fitting 44 is removed from the aperture 30 , and its associated fitting 31 , a cap 101 fitted to the fitting 31 may be inserted to prevent damage, dirt, and the like. In the illustrated embodiment, the lid closes against the bellows 96 , but may close over the bellows, in order to close up against the console 24 , which forms the outer shell of the housing 12 . Meanwhile, the base 22 is fit down into the console portion 24 .
In general, the hose 42 may be connected in any suitable manner. In the illustrated embodiment, the mask 34 may be secured permanently or temporarily to the hose 42 . The fitting 44 , typically permanently attached to the hose 42 , may include both a securement 100 and a stop 102 . The purpose of the securement 100 is as a detent to engage the fitting 31 . The purpose of the stop 102 is to prevent the fitting 44 penetrating further into the aperture 30 . Any suitable mechanism may be used including threads, quick release couplings, interfering “o” rings, or the like.
In general, the space 98 for storage of the hose 42 may actually be used as a plenum in certain embodiments. That is, for example, the space 98 may be configured on the opposite side of the base 22 , between the base 22 and the cover 26 in order to form a plenum after the hose 42 is removed therefrom. Accordingly, the surface defined by the edges of the base 22 closest to the console 24 may be a solid surface except for the opening for the grid 28 .
The bellows 96 is not required. Thus, the illustration of FIG. 12 shows the housing 12 in substantially the stowed configuration, but with the cap 101 removed. Meanwhile, the hose 42 is illustrated in order to show its positioning and sealing with respect to the aperture 30 .
Referring to FIG. 13 , the power system 20 for the apparatus 10 in accordance with the invention may be one of several possible configurations. For example, a power supply 38 may include the appropriate hardware to convert alternating current to direct current for convenience, and safety. Thus, a cord 104 may come from wall power through a plug 106 to be connected by the adapter 108 to the power supply 38 . Wall current may be converted from alternating current, at a comparatively higher voltage, to direct current, at a comparatively lower voltage, delivered through the cord 52 and subsequently the plug 54 into the apparatus 10 . Typically, a plate 110 commonly called a rating plate or “boiler plate” may contain information concerning safety, ratings, instructions, warnings, connection requirements, and the like.
Referring to FIG. 14 , a compact power supply may be used in many situations requiring comparatively lower power (e.g. a few amps or less). The apparatus 10 does not require large amounts of power (e.g. typically less than an amp down to tenths of an amp). A simple adapter 38 or power supply 38 may provide a plug 112 directly into a wall socket, feeding direct current through a cord 52 and a plug 54 into the apparatus 10 .
In an alternative embodiment the apparatus 10 may have no battery and rely solely on power from a power supply 38 , 110 for the computer. This sharing may be done in several ways. For example, the apparatus 10 may be adapted to accept the voltage and jack of the power supply 38 , 110 of a laptop computer of a user. Likewise, the apparatus 10 may have a power supply 38 , 110 sized to have the voltage and plug 54 required by a laptop computer of a user, and be rated at a current required by the more demanding of the laptop and the apparatus 10 . Thus, the power supply 38 , 110 may replace that of the laptop, requiring only one to be carried for travel. Interchangeable plugs 54 may be provided for the power supply 38 , 110 to easily adapt to power jacks as required by a laptop and the apparatus 10 .
Referring to FIG. 15 , in one embodiment, an apparatus 10 in accordance with the invention may use a battery 120 . The battery 120 may be identical to, or may be the same battery 120 as that of a laptop computer. Accordingly, a charger 118 or cradle 118 may be used to charge the battery 120 , or the battery 120 may be charged within a laptop computer.
A CPAP apparatus 10 may be carried with a computer and may share the same battery 120 . In the illustrated embodiment, a battery 120 may be fitted into a cradle 118 connected to wall power or a power supply by a cord 114 , and secured electrically by a plug 116 in the cradle 118 . In the illustrated embodiment, the output cord 52 and the plug 54 may actually be connected to the apparatus 10 .
In an alternative embodiment, a computer battery 120 may be embedded within the envelope of the apparatus 10 , and included in the space near the fan 50 of the drive system 14 within the housing 12 . A rating plate 110 or instruction plate 110 may provide the similar warnings, instructions, and connection details as discussed above.
Referring to FIG. 16 , a case 130 for an apparatus 10 may include a region for holding the apparatus 10 , divided into compartments 137 . For example, a compartment 137 a may hold the apparatus 10 , while a compartment 137 b may hold a power supply 38 , a folded cord 104 , and the like. A closure 132 , or lid 132 may be secured to the case 130 by a zipper 134 or other suitable mechanism.
Typically, a handle 136 for carrying may be adapted to a hand of a user, a shoulder strap, or the like. In the illustrated embodiment, the case 130 may be a conventional case, borrowed from the laptop computer market, may be or a specially designed case adapted to the apparatus 10 . For example, the divider 136 may be moveable, and thus may be positionable within the case 130 in order to securely stow the apparatus 10 , and still accommodate the power supply 38 , cord 136 , or other accoutrements associated with the apparatus 10 .
In certain embodiments, the cord 104 may actually be wrapped around a spooling mechanism before the tubing 42 . Likewise, the power supply 38 may be replaced with a battery 120 actually embedded in the apparatus 10 . Thus, not all embodiments of an apparatus in accordance with the invention will require separate storage for a power supply 38 and cord 104 .
Referring to FIG. 17 , a case 130 suitable for holding the apparatus 10 may be a simple compartment 130 associated with other luggage 140 , such as a briefcase. For example, certain suitcases, briefcases, and the like may be configured as a separate piece of luggage 140 having a pocket 130 interior or exterior thereto for receiving a laptop computer or the like. Accordingly, an apparatus 10 in accordance with the invention may be placed within the compartment 130 and closed by an appropriate lid 132 or cover 132 sealed by any appropriate mechanism.
In the illustrated embodiment, hook-and-loop fasteners may be formed as a securement mechanism 142 on the flap 144 and the outer portion of the case 130 or compartment 130 in order to form a proper securement keeping the lid 132 closed on the apparatus 10 . Zipper closures 134 may be formed as appropriate in any particular location, including as the sealing mechanism for the lid 132 of the compartment 130 . Any suitable system of handles, shoulder straps, and the like may be associated with the luggage 140 as known in the art.
Referring to FIG. 18 , one embodiment of an apparatus 10 in accordance with the invention may be fitted into a case 130 having a closure 132 sealed by a zipper 134 , or the like. Typically, a zipper pull 135 or more than one, may secure the zipper 134 to itself in order to close the cover 132 over the apparatus 10 . Similarly, a variety of carrying straps 138 or handles 136 may be secured on various sides in order to promote convenient carrying. Meanwhile, the apparatus 10 may be fitted within the case 130 to be easily stowed, opened, inspected, and otherwise travel just as a laptop computer would.
In certain embodiments, the tubing 42 may be configured to fit on a reel. The reel may be operated by a crank in order to wind up the tubing 42 into the housing 12 . In an alternative embodiment, the tubing 42 may be of a length selected to exactly fit with a single wrap or a few wraps about a spooling center portion 62 . The shape of a laptop computer may actually contain four or five feet of hose along its periphery. Accordingly, in one method and apparatus in accordance with the invention, the system 10 may include a simple clip system around the outer periphery of the CPAP apparatus 10 suitable for holding the tubing 42 therearound.
In yet another embodiment, a computer battery may be fitted to the apparatus 10 in accordance with the invention. The power conditioning or the motor 50 may be sized to match the battery of an individual's laptop computer. Alternatively, a power supply, such as a battery of generic configuration having power conditioning for current, voltage, and the like may be adapted to power a laptop computer, the apparatus 10 , or both. Thus, a computer battery may be matched to a user's apparatus 10 , or vice versa.
In yet another alternative embodiment, the housing 12 may be configured as a “clam shell” configuration, having a hinge 42 at the back of two substantially identical halves. The drive system 14 may be configured near the center of the housing 12 , with the delivery system 16 , principally the hose 42 or tubing 42 wrapped therearound.
The present invention may be embodied in other specific forms without departing from its basic operational principles or essential characteristics. The described embodiments are to be considered in all respects only as illustrative, and not restrictive. The scope of the invention is, therefore, indicated by the appended claims, rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope. | A compact continuous positive airway pressure apparatus and method provide a flatter profile and more compact thickness, including a larger lateral dimension in order to be accommodated in conventional luggage designed to stow laptop computers having a smaller aspect ratio of thickness to length or thickness to width. Air tubing may be coiled within a case or coiled as about a spool-like configuration in the base unit of the device. | 0 |
CROSS-REFERENCE TO A RELATED APPLICATION
[0001] This application is a National Phase Patent Application of International Patent Application Number PCT/EP2011/064452, filed on Aug. 23, 2011, which claims priority of German Utility Model Application Number 20 2010 012 567.7, filed on Sep. 8, 2010.
BACKGROUND
[0002] The invention relates to a cable deflecting piece for a cable operated window lifter which comprises at least one guide rail wherein the cable deflecting piece is to be fastened to the rail head or rail foot thereof.
[0003] From DE 38 05 576 C2 an attachment for a cable deflecting piece on a guide rail of a cable window lifter is known, whereat the guide rail is provided with a recess, into which a grip protrusion projecting from the cable deflecting piece with a nose projecting across to the longitudinal direction of the guide rail from the grip protrusion is inserted, which overlaps an edge section of the recess on the external side of the guide rail facing away from the cable deflecting piece. By a pivoting movement of the cable deflecting piece about the edge section into the mounting position with a pivoting axis parallel to the longitudinal direction of the guide rail the latching protrusion overlaps a terminal edge section of the guide rail for a locking abutment against the external side of the guide rail. For securing the cable deflecting piece in the mounting position the latching protrusion provided on the cable deflecting piece engages into a latching counter area of the guide rail when the stop protrusion is inserted into the recess, wherein a spring tongue formed in the latching protrusion blocks a pivoting movement out of the mounting position.
[0004] From DE 80 32 764 U1 a cable deflecting piece for a Bowden cable window lifter is known, which is attached to an end of the guide rail for connecting to a guide rail of the window lifter and comprises an undercut latching protrusion on the side thereof facing the guide rail, wherein between said protrusion and the cable deflecting piece a free gap is obtained, which corresponds to the material thickness of the guide rail. The latching protrusion comprises on the end of its inner side a protrusion, which engages into a recess of a guide rail when attaching the cable deflecting piece to the guide rail and secures thereby the cable deflecting piece against a removal from the guide rail. In addition an undercut nose arranged on the cable deflecting piece with a distance from the latching protrusion engages with the recess of the guide rail when attaching the cable deflecting piece and secures thus the cable deflecting piece against a tilting after attachment to the guide rail.
SUMMARY
[0005] Object of the present invention is to provide a cable deflecting piece, which allows fora simple and fast assembly when mounting the cable deflecting piece on the rail head or rail foot of a guide rail and guarantees a high stability of the connection between the cable deflecting piece and the guide rail.
[0006] The solution according to the invention allows for an insertion of the cable deflecting piece with a rotary and bearing pin projecting from the base body into a rotary and bearing opening of the rail head or rail foot in a position tilted in relation to the longitudinal extension of a guide rail and performs thus an exact prepositioning without that a readjustment of the cable deflecting piece for the mounting thereof on the rail head or rail foot is required. By subsequent rotation or pivoting of the cable deflecting piece about the mounting rotation axis formed by the rotary and bearing pin projecting from the base body and the rotary and bearing opening on the rail head or rail foot a rotation prevention means is activated in a final mounting position, which secures the connection of the cable deflecting piece to the rail head or rail foot against an undesired rotation of the cable deflecting piece about the mounting rotation axis, and a secure, stable abutment of the base body against the rail head or rail foot perpendicular to the longitudinal extension of the guide rail, that means in X-direction as well as also in particular in Y-direction of a motor vehicle with a cable window lifter installed in a motor vehicle door is guaranteed by the device formed on the base body for securing the abutment.
[0007] Due to the form fitting connection of the rotary and bearing pin projecting from the base body to the rotary and bearing opening formed in the rail head or rail foot the cable deflecting piece is secured against a removal from the rail head or rail foot, the assembly thereof is alleviated due to an exact guidance of the cable deflecting piece by the formation of the mounting rotation axis, an unintended deassembly of the cable deflecting piece from the guide rail via back rotation is prevented by the rotation prevention and due to the device formed on the base body for securing the abutment of the base body against the rail head or rail foot a tilting of the cable deflecting piece perpendicular to the longitudinal extension of the guide rail that means perpendicular to the guiding plane of the guide rail is prevented. Due to this multiple securing of the cable deflecting piece, which is affected by a simple mounting with an inserting and pivoting movement, a secure connection of the cable deflecting piece to the rail head or rail foot of a guide rail is also guaranteed under load.
[0008] Alternatively or in addition to a corresponding design of the rotation prevention means and the device for securing the abutment of the base body against the rail head or rail foot a stop area can be formed on the base body of the cable deflecting piece for a further alleviation of the mounting, which abuts in the final mounting position against a part of the terminal edge of the rail head or rail foot and prevents thus a further rotation or pivoting of the cable deflecting piece about the mounting rotation axis.
[0009] The rotation prevention means comprises advantageously at least one latching element integrated into the base body which snaps after a pivoting of the cable deflecting piece about the mounting rotation axis in the final mounting position into a latching recess on the rail head or rail foot.
[0010] This design of the rotation prevention means prevents with a simple constructive means a back rotation of the cable deflecting piece into the starting mounting position and secures in combination with the stop area formed on the base body the cable deflecting means against a rotation about the mounting rotation axis in both rotation directions.
[0011] A first latching element consists of a latching nose projecting from the base body with a lead-in chamfer and a latching edge, which abuts in the final mounting position of the cable deflecting piece against a latching edge of a recess formed as a latching receptacle in the rail head or rail foot of the guide rail.
[0012] Alternatively, but preferably in addition to the first latching element, a second latching element is provided which consists of an elastic, bendable latching hook projecting from the base body, which when mounting the cable deflecting piece on the rail head or rail foot of the guide rail by pivoting the cable deflecting piece about the mounting rotation axis slides at least partially on a first side arm of the guide rail in an elastic relentless manner and abuts in the final mounting position against a latching stop on rail head or rail foot of the guide rail.
[0013] Due to the arrangement of in particular two latching elements a high degree of rotation security of the cable deflecting piece is provided such that also large cable forces occurring when operating the cable window lifter do not cause a rotation of the cable deflecting piece out of the final mounting position or operating position and thus the danger of an undesired release of the connection of the cable deflecting piece to the rail head or rail foot of the guide rail occurs.
[0014] The device for securing the abutment of the base body against the rail head or rail foot consists preferably of at least one rear grip originating from the base body and encompassing at least partially a terminal edge of the rail head or rail foot.
[0015] The rear grip is effective in connection with the stop area against a tilting of the cable deflecting piece in X-direction of a motor vehicle and against a removal or tilting of the cable deflecting piece in Y-direction of a motor vehicle.
[0016] The rear grip is thereby formed such that it is distanced after the insertion of the rotary and bearing pin into the rotary and bearing opening in position of the cable deflecting piece tilted in relation to the longitudinal extension of the guide rail and before rotating or pivoting the cable deflecting piece about the mounting rotation axis from the terminal edge of the rail head or rail foot and encompasses the terminal edge in the final mounting position.
[0017] Also the device formed as a rear grip for securing the abutment of the base body against rail head or rail foot can be formed as one piece or in multiple pieces, wherein in particular a multi-piece formation of the rear grip prevents a release of the base body from the abutment against the rail head or rail foot against a tilting in different directions in relation to the stop area of the rail head or rail foot and guarantees thereby the secure abutment of the cable deflecting piece in X- and in particular in Y-direction of the cable window lifter assembled into a motor vehicle door.
[0018] A first rear grip formed on the base body encompasses the terminal edge of a central arm of the guide rail and abuts with a section continuing parallel to the terminal edge of the central arm in the final mounting position against the side of the rail head or rail foot of the guide rail opposing the base body, wherein in between the first rear grip and the base body a slot for inserting the terminal edge of the central arm of the guide rail is provided.
[0019] The first rear grip secures a tight and lasting abutment of the base body and thus of the cable deflecting piece against the rail head or rail foot of the guide rail in Y-direction of a motor vehicle by encompassing the terminal edge of the central arm of the guide rail wherein the slot between the base body and the front side of the strip-like first rear grip receives the terminal edge.
[0020] As an alternative or preferably in addition to the first rear grip a second rear grip can be provided, which is formed as an arm projecting from the base body, which encompasses in the final mounting position a chamfer continuing from the terminal edge of the central arm to the latching stop of the first side arm at an obtuse angle to the terminal edge of the central arm and abuts in the final mounting position with a flat section against the side of the rail head or rail foot of the guide rail opposing the base body.
[0021] Since the second rear grip encompasses the terminal edge of the rail head or rail foot of the guide rail in the area of the chamfer it secures the abutment of the cable deflecting piece in Y-direction as well as the embedding of the base body of the cable deflecting piece into the U-profile of the guide rail and thus also in X-direction of the motor vehicle.
[0022] In order to prevent a collision of the second rear grip with the guide rail when inserting the rotation and bearing pin into the rotation and bearing opening in tilted position of the cable deflecting piece the second rear grip comprises an inclined edge corresponding to the obtuse angle of the chamfer such that when inserting the rotary and bearing pin of the cable deflecting piece into the rotary and bearing opening on the rail head or rail foot of the guide rail the inclined edge continues essentially parallel to the chamfer.
[0023] Altogether this guarantees that in a starting mounting position in which the cable deflecting piece is positioned on the guide rail in a tilted position in respect to the longitudinal extension of the guide rail and the rotary and bearing pin projecting from the base body of the cable deflecting pin is inserted into the rotary and bearing opening of the rail head or rail foot of the guide rail the rear grip collides with the guide rail. Only when pivoting the cable deflecting piece about the mounting rotation axis formed by the rotary and bearing pin and the rotary and bearing opening into the final mounting position the rear grip comes to an abutment against the side of the rail head or rail foot opposing the base body and secures thus the base body against a removal or tilting perpendicular to the guiding area of the guide rail.
[0024] For alleviating the insertion of the rotary and bearing pin projecting from the base body of the cable deflecting piece into the rotary and bearing opening on the rail head or rail foot the rotary and bearing pin is provided on the terminal side with a circumferential lead-in chamfer.
[0025] Besides the rotary and bearing pins serving as mounting aid and being effective as part of a position securing as well as latching and locking elements securing the connection of the cable deflecting piece to the rail head or rail foot of the guide rail the cable deflecting piece comprises as functional elements a carrier stop, which abuts against the terminal edges of an edge arm and a second side arm of the guide rail consisting of ZU-profile for a carrier of the cable window lifter adjustable along the guide rail, which is preferably arranged adjacent to the stop area, which is formed on the base body and abuts in the final mounting position against a part of the terminal edge of the rail head or rail foot, as well as a bended tubular guiding channel for a window lifter cable, which contains a Bowden support on the opening thereof directed away from the guide rail.
[0026] The cable deflecting piece is formed in one piece as injection moulding piece for a simple manufacturing and precise formation of the rotary and bearing pin and the latching and locking elements.
[0027] Alternatively the base body and the latching and locking elements can consist of one singular injection moulding piece, into which the rotary and bearing pin is inserted, in particular injected, as separate metal part, preferably made of steel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The idea on which the invention is based on and the different variants of the solution according to the invention shall be indicated and explained by the means of the embodiments illustrated in the Drawings.
[0029] FIG. 1 shows a schematic isometric illustration of a rail head and a cable deflecting piece before mounting the cable deflecting piece on the rail head.
[0030] FIGS. 2 to 4 show isometric views of the front and back side of the cable deflecting piece.
[0031] FIGS. 5 and 6 show schematic illustrations of a cable deflecting piece and a rail foot of a guide rail in a mounting starting position and an mounting final position or operating position of the cable deflecting piece.
[0032] FIGS. 7 to 10 show isometric illustrations of the front and back side of the rail head of a guide rail with a cable deflecting piece attached to the rail head in tilted position in the mounting starting position and fastening the cable deflecting piece to the rail head in the mounting final position.
[0033] FIG. 11 shows a schematic isometric illustration of the cable deflecting piece connected to the rail head of a guide rail in the mounting final position.
[0034] FIG. 12 shows an enlarged isometric illustration of a part of a cable deflecting piece connected to the rail head.
DETAILED DESCRIPTION
[0035] In FIGS. 1 to 12 the upper end of a guide rail designated as rail head 17 or the lower end of a guide rail 1 designated as rail foot 18 of an otherwise not illustrated single or double stranded cable window lifter is illustrated within a motor vehicle door. A carrier, which is also not illustrated, is movably arranged on the guide rail 1 in longitudinal direction of the guide rail, which is connected to a window pane, which is lifted and lowered according to the moving direction of the carrier. For this purpose the carrier is connected to a window lifter cable, which is guided in a closed loop and is guided by a manual or motored window lifter drive to a cable deflecting piece 3 illustrated in FIGS. 1 to 12 on the rail head 17 along the guide rail 1 to a corresponding cable deflecting piece on the rail foot 18 back to the window lifter drive. Between the two cable deflecting pieces 3 on rail head 17 and rail foot 18 the window lifter cable is connected to the carrier, for instance via a cable nipple supported in a nipple chamber of the carrier.
[0036] The window lifter cable can be guided in a Bowden cable cover between the cable deflecting pieces 3 and the cable lifter drive, which is supported by a Bowden support 34 according to FIGS. 1 to 4 .
[0037] As deducible from the isometric illustration of FIG. 1 the guide rail 1 comprises a ZUprofile, which consists of a U-profile with a centre arm 10 , wherein side arms 11 , 12 vertically project from the ends thereof, and an edge arm 13 projecting vertically outwards from the side arm 12 .
[0038] The rail head 17 or rail foot 18 comprise for mounting the cable deflecting piece 3 according to FIGS. 1 and 5 to 12 in the centre arm 10 a preferably rectangular recess 21 and a continuous rotary and bearing opening 23 . A chamfer 15 continues from the terminal edge 14 of the centre arm 10 to the side arm 11 , which is not connected to the edge arm 13 , wherein on the side arm sided end of said chamfer a latching stop 16 is provided.
[0039] The cable deflecting piece 3 consists of a base body 30 , which is arranged after connect ing the cable deflecting piece 3 to the rail head 17 or rail foot 18 in the mounting final position or operating position on the inner side of the ZU-profile of the guide rail 1 in the area of the U-profile between the side arms 11 , 12 . As in particular deducible from the isometric illustrations of FIGS. 2 to 4 , a rotary and bearing pin 4 projects from the base body 30 , wherein said pin comprises a circumferential chamfer 40 on its end facing away from the base body 30 .
[0040] The rotary and bearing pin 4 is inserted—as explained in more detail in the following—in the mounting starting position in a, in respect to the mounting final position or operating position of the cable deflecting piece 3 into the rotary and bearing opening 23 on the rail head 17 or rail foot 18 such that the base body 30 comes to abutment against the inner side of the rail head 17 or rail foot 18 .
[0041] The base body 30 contains a bended tubular cable channel 33 , which comprises on one end thereof a Bowden support 34 and which passes on its other end into a sliding channel 35 for the window lifter cable. In the mounting final position or operating position of the cable deflecting piece 3 the sliding channel 35 is directed to the longitudinal extension of the guide rail 1 , while the opening provided on the opposite end of the cable channel 33 points with the Bowden support 34 to the window lifter drive.
[0042] In the mounting final position or operating position a stop area 31 formed on the base body 30 abuts against the terminal edges 19 of the side arm 12 and edge arm 13 of the rail head 17 or rail foot 18 as terminal stop. Adjacent to the stop area 31 a stop 32 is formed stepwise for the carrier guided in a longitudinally adjustable manner on the guide rail 1 .
[0043] Multiple latching and locking elements are integrated into the base body 30 of the cable deflecting piece 3 , which serve in different functions for rotation prevention or for securing the abutment of the cable deflecting piece 3 in Y direction on the rail head 17 or rail foot 18 . For rotation prevention a latching element integrated into the base body 30 is provided according to FIGS. 2 to 4 , which is formed as latching nose 5 with a lead-in chamfer 50 and a latching edge 51 and snaps in the mounting final position into the recess 21 on the rail head 17 or rail foot 18 such that the latching edge 51 of the latching nose 5 abuts against a latching edge 22 of the recess 21 and thus a back rotation of the cable deflecting piece 3 out of the mounting final position or operating position into the mounting starting position is prevented.
[0044] In the same manner a second latching element acts, which is formed as latching hook 6 and comprises an elastic bar 60 and a latching head with a latching edge 61 , which abuts in the mounting final position against the latching stop 16 on the terminal edge of the side arm 11 and also prevents a back rotation of the cable deflecting piece 3 out of the mounting final position into the mounting starting position.
[0045] For securing the abutment of the base body 30 against the inner side of the rail head 17 or rail foot 18 and thus for securing the cable deflecting piece 3 in direction vertical to the area of the guide rail, that means for securing the cable deflecting piece 3 in Y direction of the motor vehicle in case of a cable window lifter inserted into a motor vehicle door adjacent to the latching nose 5 a first strip-like rear grip 7 is provided, which encompasses the terminal edge 14 of the centre arm 10 of the rail head 17 or rail foot 18 and abuts against the section of the external side of the rail head 17 or rail foot 18 adjacent to the terminal edge 14 . For receiving the terminal edge 14 and the sections following the terminal edge 14 an insertion slot 36 is provided on the internal side and external side of the rail head 17 or rail foot 18 according to FIG. 4 .
[0046] A second rear grip 8 is provided adjacent to the first strip-like rear grip 7 , which encompasses the chamfer 15 between the terminal edge 14 of the centre arm 10 and the latching stop 16 of the side arm 11 and abuts also against the external side of the rail head 17 or rail foot 18 . The second rear grip 8 comprises an inclined edge 80 , which faces in the mounting starting position the chamfer 15 and thus allows the insertion of the rotary and bearing pin 4 into the rotary and bearing opening 23 .
[0047] FIGS. 5 and 6 show in a schematic top view the previously, by the means of FIGS. 1 to 4 described mounting, latching and locking elements of the cable deflecting piece 3 and the rail head 17 or rail foot 18 of the guide rail 1 for aligning and mounting the cable deflecting piece 3 to the rail foot 18 of the guide rail 1 as well as the mounting steps starting from an mounting starting position illustrated in FIG. 5 into an mounting final position or operating position of the cable deflecting piece 3 in respect to the guide rail illustrated in FIG. 6 .
[0048] FIG. 5 shows schematically the cable deflecting piece 3 in the mounting starting position, in which it is tilted in respect to the longitudinal extension of the guide rail 1 such that the inclined edge 80 of the second rear grip 8 is aligned almost parallel to the chamfer 15 on the rail foot 18 and the strip-like first rear grip 7 serving as Y protection is opposite to the crossing of the terminal edge 14 of the centre arm 10 to the chamfer 15 and the latching head of the latching hook 6 is opposite to the internal side of the side arm 11 . In this tilted position of the cable deflecting piece 3 the rotary and bearing pin 4 is inserted into the rotary and bearing opening 23 of the rail foot 18 , wherein the circumferential chamfer of the rotary and bearing pin 4 allows for the insertion into the rotary and bearing opening 23 .
[0049] After inserting the rotary and bearing pin 4 into the rotary and bearing opening 23 until abutment of the base body 30 against the internal side of the rail foot 18 the cable deflecting piece 3 is pivoted in direction of arrow A about the mounting rotary axis formed by the rotary and bearing pin 4 and the rotary and bearing opening 23 , wherein the latching head of the latching hook 6 slides along the internal side of the side arm 11 and the second rear grip 8 slides with its inner face along the external side of the centre arm 10 and the latching nose 5 slides along the internal side of the centre arm 10 . The insertion slot 36 formed between the strip-like first rear grip 7 and the base body 30 moves thereby over the terminal edge 14 of the centre arm 10 .
[0050] The rotation of the cable deflecting piece 3 is continued until the stop area 31 abuts against the terminal edge 19 of the side arm 12 and edge arm 13 , the latching nose 5 snaps into the recess 21 of the rail foot 18 and the latching edge 61 engages at the latching head of the latching hook 6 with the latching stop 16 at the end of the side arm 11 . In this mounting final position or operating position of the cable deflecting piece 3 illustrated in FIG. 6 the second rear grip 8 abuts with its inner face against the external side of the centre arm 10 and the strip-like first rear grip 7 abuts for Y-protection of the cable deflecting piece 3 against the section of the external side of the rail foot 18 being adjacent to the terminal edge 14 of the centre arm 10 , while the insertion slot 36 encompasses the terminal edge 14 of the centre arm 10 . Herewith the cable deflecting piece 3 is secured against a removal of the base body 30 from the internal side of the rail foot 18 and against a tilting in Y-direction as well as against a rotation of the cable deflecting piece 3 by engagement of the latching nose 5 into the recess 21 and abutment of the latching edge 51 of the latching nose 5 against the latching edge 22 of the recess 21 as well as of the latching edge 61 of the latching hook 6 against the latching stop 16 of the side arm 11 .
[0051] After inserting the rotary and bearing pin 4 in tilted position of the cable deflecting piece 3 into the rotary and bearing opening 23 on the rail foot 18 a simple pivoting movement of the cable deflecting piece 3 about the mounting rotation axis formed by the rotary and bearing pin 4 as well as the rotary and bearing opening 23 provides a locking of the cable deflecting piece 3 in the mounting final position with a rotarion protection and protection in X-, Y- and Z-direction or protection against a tilting or removal of the base body 30 from the internal side of the rail foot 18 such that the cable forces acting during the operation of the cable window lifter onto the cable deflecting piece 3 can be received steadily without changing the position of the cable deflecting piece 3 in respect to the rail foot 18 of the guide rail 1 .
[0052] In FIGS. 7 and 8 there are illustrated in isometric views of the internal side of the rail head 17 and in FIGS. 9 and 10 —with schematically transparent illustration of the rail head 17 —there are illustrated in isometric views of the external side of the rail head 17 the mounting of the cable deflecting piece 3 on the rail head 17 in the mounting starting position ( FIGS. 7 and 9 ) as well as in the mounting final position or operating position ( FIGS. 8 and 10 ).
[0053] FIGS. 7 and 9 show in isometric view of the internal side and external side of the rail head 17 of the guide rail 1 the mounting starting position, in which the cable deflecting piece 3 is positioned in a tilted position in respect to the mounting final position on the rail head 17 and the rotary and bearing pin 4 is inserted into the rotary and bearing opening 23 , wherein the inclined surface 80 of the rear grip 8 is directed almost parallel to the chamfer 15 of the terminal edge of the rail head 17 and opposes the latching hook 6 of the internal side of the side arm 11 .
[0054] By pivoting the cable defecting piece 3 about the mounting rotation axis formed by the rotary and bearing pin 4 and the rotary and bearing opening 23 the latching hook 6 is guided along the internal side of the side arm 11 and the latching nose 5 is guided in a circular arc to the recess 21 . Shortly before approaching the mounting final position the inserting slot 36 is moved over the terminal edge 14 of the centre arm 10 until the stop area 31 comes to abutment against the terminal edge 19 of the side arm 12 and edge arm 13 in the mounting final position illustrated in FIGS. 8 and 10 , the latching nose 4 snaps into the recess 31 and the latching edge 51 of the latch nose 5 abuts against the latching edge 22 of the latching opening 21 . Simultaneously, the latching edge 61 of the latching hook 6 engages via the latching stop 16 at the end of the side arm 11 and secures together with the latching nose 5 the cable deflecting piece 3 against a rotation about the mounting rotation axis.
[0055] Thereby, the strip-like first rear grip 7 comes to an abutment against the section of the external side of the rail head 17 being adjacent to the terminal edge 14 of the centre arm 10 and secures in interaction with the second rear grip 8 the cable deflecting piece in Y-direction as well as the abutment of the base body 30 of the cable deflecting piece 3 against the internal side of the rail head 17 , which is formed by the U-profile of the centre arm 10 and the two side arms 11 , 12 .
[0056] FIG. 11 shows the mounting final position or operating position of the cable deflecting piece 3 and FIG. 12 shows an enlarged section of the illustration according to FIG. 11 with a transparent illustration of the rail head 17 of the guide rail, respectively.
[0057] In the mounting final position the sliding channel 35 of the cable deflecting piece 3 is aligned in longitudinal direction of the guide rail 1 , while the cable channel 33 is directed in an inclined manner away from the rail head 17 . The stop are 31 of the cable deflecting piece 3 abuts against the terminal edges 19 of the side arm 12 and the edge arm 13 . The rotary and bearing pin 4 with its chamfer 40 projects through the rotary and bearing opening 23 and the latching nose 5 serving the rotation protection is snapped in to the recess 21 and abuts against the latching edge 22 of the recess 21 with its latching edge 51 . The first strip-like rear grip 7 encompasses the terminal edge 14 of the centre arm 10 and abuts against the sections of the external and internal side of the centre arm 10 of the rail head 17 , which flank the terminal edge 14 , wherein the inserting slot 36 on the cable deflecting piece 3 receives the terminal edge 14 .
[0058] FIG. 12 shows as a dashed line the chamfer 15 of the rail head 17 encompassed by the second rear grip 8 as well as the inclined edge 80 of the second rear grip 8 , which encompasses diagonally this section of the rail head 17 . | A cable deflecting piece, which is fastened on a rail head or rail foot of a guide rail and is intended for a cable operated window lifter, contains a base body which during mounting and following fastening of the cable deflecting piece, abuts against the guide rail on one side of the rail head or rail foot, also contains a rotary and bearing pin, which projects from the base body, can be inserted in a position in which it is tilted in relation to the longitudinal extension of the guide rail, into a rotary and bearing opening of the rail head or rail foot and can be pivoted about a cable deflecting piece, further contains a rotation prevention means which, in a final mounting position, once the cable deflecting piece has been pivoted about the mounting axis of rotation, secures the connection of the cable deflection piece to the rail head or rail foot such that the cable deflecting piece cannot rotate and additionally contains a device which is formed on the basic body and is intended for securing the abutment of the base body against the rail head or rail foot perpendicular to the longitudinal extension of the guide rail. | 4 |
This application is a continuation of now abandoned application, Ser. No. 865,024 filed on May 20, 1986 now abandoned.
BACKGROUND OF THE INVENTION
This invention relates to a controling method for a photographic system which is capable of detecting and controlling photographic characteristics which are subject to chronological changes (e.g. development process characteristics, printing condition characteristics, etc.) with a high precision. It further relates to a normalization method for photographically measured data of three primary colors.
The factors which should be taken into consideration for controlling a photographic system involve not only the factors which can be learned by simple measurement (for instance, changes of the light source in a photographic printer) but also complicated factors which are subject to interaction of various conditions (development process characteristics, printing condition characteristics and image reproduction characteristics, etc.). For instance, the data on the development process characteristics contain variation in the performance of photographic photo-sensitive materials (usually the control film) used in detection, the chronological changes thereof and variation in densitometers besides the characteristics of the developing agents per se. Photographic printing conditions similarly involve the variations in characteristics of the printing film, objects, light sources and/or printers besides the above development process characteritics which should be comprehensively considered and judged for optimum control or administration. Such control or administration usually needs manipulation of a device or experience or skill of an operator and even with these contributions of men, it cannot always be performed at a high precision. The control or administration of these sytems are preferably conducted automatically without need for human contribution, and it needs a method and system which are capable of quantitatively measuring the conditions.
Since all of these variables in photographic characteristics are difficult to separately measure and control, the control should be based on a small amount of data with which conditions can be comprehensively grasped or a small amount of data which have high correlation with such variations.
When gray images of an original film are measured photographically as they are printed in three primary colors of RGB by a photographic color printer, the photographic values obtained for RGB are neither identical in image density at the same exposure amount nor in the ratio of image densities of the three colors against a series of exposure amounts as shown in FIG. 1. They are subject to variations depending on the development process and/or the photo-sensitive materials. This is partly because optimally reproduced images can be obtained by a combination of a negative film sheet as an original film which should be printed and a photographic paper which is a printing material, usages are different for each type of photosensitive materials, design concepts differ depending on the manufacturer, and it involves variations in the development process characteristics and the photometric fiber characteristics of the original film. When the photometric values for three primary colors do not have the same characteristics, the film densities and colors may often fluctuate for the same object. More specifically, a blue sky may be reproduced with a density similar to a gray clouded sky, which greatly affects subsequent processing such as the determination of exposure amount or color correction. Since the sensitivity of RGB or gradation balance is varied depending on the photographic paper types or the developing processes, the color or the density of a negative film may often be erroneously judged in detection or control. It is desirable that the same object be photographed on a negative film sheet at a constant density and in color irrespective of the types of the photographic paper or the developing processes. In the prior art, the photometric values in RGB are normalized as shown in FIG. 2. The nomalization method, however, is detrimental in the following aspects.
Japanese Patent Laid Open No. 145620/1978 discloses a hue extraction device comprising a means for correcting the sensitivity by adding a given constant to the density signals of blue, green and red, and a nomalization means having a means for γ-correction by amplifying density signals. The application does not refer to the method for obtaining the correction amount in sensitivity and the γ-correction amount, and requires in practice preparation of reference negative film sheets for various types of the photographic materials at suitable interval to be used in obtaining the correction amount. The method therefore is cumbersome as it must decide which a reference film should be used and it needs preparation thereof and determination of the correction amount. The photographic printing conditions can be determined based on the sensitivity of a film and γ-value aiming at the same effect as the normalization of the film. The prior art photographic printing conditions, however, include the characteristics of a photographic paper and a photographic printer, which makes the γ-value of a film difficult to be obtained from the slope control values related thereto. The determination of printing conditions and the administration thereof present formidable difficulties in practice. The method, therefore, can not quite achieve the above mentioned effect.
Japanese Patent Laid Open No. 30121/1981 discloses a method which sequentially corrects the deviation of the average of a large number of frames from a reference value in the large area transmittance density (LATD). The method is used to correct the correction coefficients of the photographic values by using the average of normalized densities and not to obtain the correction coefficients thereof. Since the method sequentially corrects the data, it can correct the normalization conditions only very slowly and it may not converge to a value. The prior application does not mention any process for the correction of gradation.
Japanese Patent Publication No. 10730/1975 discloses a decision formula for detecting the subjective color failures which uses a constant proportional to the reciprocals of the average density and gradation of the reference negative film. The method aims at checking the presence/absence of the difference in RGB densities between the reference negative film and a negative film to be printed, which also involves the use of the reference negative film.
There has long been desired by many a method which is capable of automatic controlling of the film characteristics (i.e. densities or gradation balance, etc.) which are subject to variation depending on the developing process for the optimum exposure control.
SUMMARY OF THE INVENTION
This invention was conceived in order to eliminate aforementioned troubles encountered in the prior art and aims at providing a controlling method for photographic systems which can assume the current conditions of the chronologically variable photographic characteristics by processing data up to the time point so as to optimally control and administer the system with suitably up-dated data.
Another object of this invention is to provide a method which can normalize the data in RGB at a high precision in a color photographic printer.
Stil another object of this invention is to provide a method for normalization of data in photographic printing systems which allows automatic adjustment of a photographic printer to variations in developing process, notifies an operator when a predetermined quality can not be sustained any more so that high quality operation can be constantly maintained by replacement of developing agents and can be easily used by unskilled operators.
According to one aspect of this invention, for achieving the objects described above, there is provided a controlling method for a photographic system which is characterized in that photographic characteristics of the system are measured and stored chronologically, the importance of said photographic characteristics are varied as time functions to obtain weighted average characteristics, and said photographic system is controlled based on such weighted average characteristics in an analogical manner.
According to another aspect of this invention, there is provided a normalization method for measured data in a photographic system of the type where printing exposure is determined based on the photographic data obtained from measurement of an original film roll in three primary colors and said original film is printed with thus determined exposure, in which correction coefficients are obtained based upon uncorrected data accumulated for said original film, and said measured data are normalized based on said corrction coefficients.
Furthermore, according to still another aspect of this invention, there is provided a normalization method for measured data in a photographic system of the type where printing exposure amunt is determined based on the photographic data obtained from measurement of an original film roll in three primary colors and said original film is printed with thus determined exposure amount, in which a conversion table is prepared when predetermined conditions are met, by transforming frame characteristics on a large number of original film rolls into predetermined reference values based upon stored data and normalizing said measured data in accordance with the conversion table.
The nature, principle and utility of the invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings:
FIGS. 1 and 2 are graphs for explanation of the prior art normalization;
FIGS. 3 through 5 are graphs which respectively describe one example of this invention control method;
FIG. 6 is a flow chart to obtain average characteristics of a film according to this invention;
FIG. 7 is a flow chart to show one example of addition and initialization according to this invention;
FIGS. 8A and 8B are explanatory graphs of application of this invention method to the determination of photographic printing conditions;
FIG. 9 is a block diagram which shows one example of a device to realize this invention normalization method;
FIGS. 10A through 10C are graphs to describe normalization according to this invention;
FIG. 11 is a block diagram of another embodiment of this invention;
FIG. 12 is an explanatory graph to show how to determine density divisions;
FIG. 13 is a block diagram which shows a device to realize still another embodiment of the normalization method according to this invention;
FIGS. 14 and 15 are graphs which explain the normalization; and
FIG. 16 is a block diagram to show still another embodiment of the normalization according to this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
This invention attempts to control a photographic system which is subject to chronological changes by sequentially storing the photographic characteristics of the system, using the same as a chronological function to modify the importance of each characteristic to obtain a weighted average photographic characteristic. More particularly, positive weights are added to the photographic characteristics of predetermined time (e.g. one day or ten days) or a predetermined amount (e.g. 1,000 frames) consecutively in a manner that the weight becomes smaller as the data goes retrogressively afar from the current time point, and the control is conducted based on the weighted moving average photographic characteristics. The photographic characteristics of a predetermined time or amount may be determined as an average of individual photographic characteristics within a predetermined scope (e.g. time or amount), and that may be stored to obtain the weighted average photographic characteristics. Weight may be varied for each storage. The photographic characteristics of a predetermined time or amount may be weighted to sequentially renew the average or sum thereof and to change weight for each time as shown in FIG. 3. In the case shown in the figure, the weighted average up to M is multiplied with a weight coefficient W (W <1.0) and added to the average of (M +1) to renew the weight.
Alternatively, as shown in FIG. 4, a stored number N of the photographic characteristics is set in relation to time within the scope not above the limit N u and not below the limit N l and when the data number has reached the upper limit N u , it is transformed to the lower limit N L to start from the value anew. If the sum and the data number are stored, when the data number has reached the upper limit N u , the process starts anew from the value obtained by multiplying the sum and the data number with n (n<1 and n≠0). Alternatively, an average value may be stored in place of the sum. More particularly, if the average A, the data number is N and the photographic characteristics at the current time point is A o , the equation below holds in storage;
A=(A·N+A.sub.o)/(N+1)
=N+1
and when the number N has reached the upper limit N u , as N=N l , the process starts again anew.
It is assumed that N L =N u ·n, and n is a positive number smaller than 1 (for instance 1/2, 2/3. . . ).
FIG. 5 shows another method to determine the weighting coefficient. In this weighted moving average method, the data in the past is weighted relatively less than the data closer to the current time point to estimate the current situation.
FIG. 6 shows an example to obtain the average characteristic of film sheets. A sheet of film is photometrically measured (1) by an image sensor and so on, the type of the film is classified (2) as (A, B, .....N) based on the class information and the photographic characteristics Dare stored. When the stored number N is smaller than 2,000, it is operated and processed (3) with the average D x obtained from the stored data on all the film sheets, and when the data number is larger than 2,000, the stored average D x is not used, but the average characteristics obtained from the stored data on individual film sheets is sued for the control (4) for photographic printing. More specifically, if 100 film rolls are processed per day for one type of film (in other words, ca. 2,000 data/day), and if the range is limited at 4,000 at the ceiling and at 20,000 at the bottom, the weight is modified once in a 10-day cycle. The upper and bottom limits are preferably changed for each type of the film rolls depending on the amount of process. The changes in film development and seasonal variation are sequentially traced to detect the amount thereof and control is conducted based thereon. In the control based on the average of a large number of data, the contribution of a data of the 1,000th frame to the control differs from that of a data of the 100,000th frame. Although the precision as an average of the data of 100,000 frames is higher, it is contradictorily less efficient as the data to estimate the current conditions. In other words, although it takes a long time to store a large amount of data, the farther past the data concerns, the less it reflects the current situation. This invention solved such a contradictory problem by using a weighted moving average.
In FIG. 6 in the control of the printing conditions, for example, the average characteristics is expressed in the average LATD (Large Area Tansmittance Density) and the operational processing is conducted on the difference between the reference LATD and an obtained averag LATD. It represents that the developing characteristics deviate from the reference value by the LATD difference and the printing conditions are corrected or adjusted to eliminate such a deviation. The operational processing needed for normalization of a characteristic curve which is variable depending on the type of film is the calculation of normalization conditions. If the data number is 2,000 or less, it may use the initial value which has been stored in advance and the system may include initial input means therefor.
FIG. 7 shows a flow chart to describe an example of addition and initialization.
More particularly, the data Di'on each frame is obtained by the photometric measuring with an image sensor and so on (Step S1); the density D'is added and the number N is added (Step S2); and the above measuring steps are repeated for one roll of the film (Step S3). After such a photometric measurement is conducted for a predetermined number times, it is processed by addition of the average A and the number N stored in a memory (Step S4). If the number N has not reached a predetermined upper limit N u , the average and the number thereof are stored in a memory as they are (Steps S5 and S8), and if it has reached the upper limit N u , the number is returned and stored as the bottom limit N L (Steps S6 and S8). Above steps are repeated until the suspension of the measurement (Step S7). The data stored in the memory should be erased when the developing agent is replaced, the type of film is switched to another type, or the photographic system or the printer fails. it is desirable to include a means which can erase the stored data or return the data to an initial value with an external input.
This invention method may be applied in various manners other than above in the photographic printing condition determination; for instance, it can be utilized in determination of a coordinate point, a coordinate region or correction amount on a color coordinate system of a film which has been exposed with tungsten light. It is also applicable to the determination of the tendency of density correction or color correction to obtain the most suitable conditions. It may be aplied to the detection and correction of the chronological deterioration or the various changes in measurement device of the image, display unit or output device. FIG. 8A shows the clipping of data in relation to time while FIG. 8B exemplifies the weighting coefficients of the past data.
Although the photographic characteristics are variables of time, since they are weighted with the data up until the current time point by estimating the current conditions in this invention method, suitable and precise control and administration thus becomes possible.
FIG. 9 is a block diagram of the system which realizes this invention normalization method wherein a color negative film as an original film is photometrically measured (10) in the three primary colors of RGB with photodiodes or an image sensor, the characteristics 15 (e.g. average density, the maximum density, the minimum density) for exposure control are obtained from the density values due to the data obtained in the measurement, the exposure amunt is calculated (16) with the characteristics 15 in accordance with a predetermined formula, and a photographic printer is controlled (17) in exposure with the obtained exposure amount. Simultaneously, the characteristics 11 (such as average density on the whole or portions of a frame, the maximum or the minimum density, density histogram or hues, etc.) on a frame are obtained, and the characteristics 11 are stored in a memory 14. From the data stored in the memory 14, the correction coefficients (or constants) 13 are obtained to correct (12) the density values obtained from the measurement 10 and the characteristics 15 for the exposure control are calculated based upon the result of the above correction.
The characteristics 11 obtained from the photometric measuring 10 are compared with predetermined density divisional values, the average of frames having the characteristics larger than the division are expressed as A j while the average data of frames having the characteristics smaller than it are expressed as B j . As j=1, 2, 3 or R, G, B, the correction coefficient 13 to normalize the measured data is obtained by A j and B j or combination thereof. For instance, if it is assumed that the measured data is Dij and the correction value is D' ij , the correction coefficients for gradation and the correciton coefficients for density balance may be respectively obtained by a combination of A j and B j . When normalization is conducted based on the data G out of the measured data on the three primary colors, it may be obtained by the following calculation. ##EQU1## when the measured data on RGB should be normalized based upon a predetermined film characteristic curve, it may be calculated according to the following equation (2). ##EQU2##
K in the former equation (1) may be B 2 or it may be calculated based on B 1 or A 1 . S j and G j in the above equation (2) are reference values. Correction with B 1 , B 2 and B 3 may be conducted after the gradient on D ij is normalized in the above equations (1) and (2). In place of D i1 , D i2 and D i3 , a color difference value comprising a combination of two or three colors thereof may be obtained. The normalization method of this invention is by no means limited to the above equations (1) and (2). For instance, a predetermined and present value may be used to replace the gradation correction value in the equation (1).
FIGS. 10A through 10C show the states of RGB-normalization of the meaured data for G and R based on G according to the equation (1). FIG.10A illustrates actual data obtained from the photometric mesurement. Gains are corrected in order to make B 1 =B 2 by means of the equations R'=R-B 1 and G'=G-B 2 (FIG.10B). The data are further normalized by γ-correction to achieve the relation R'=(R-B 1 )·{(A 2 B 2 )/(A 1 -B 1 )}+B 2 and G"=G. The state illustrated in FIG. 10C is thus obtained. The same object can be reproduced at the same density and in the same color by transforming the density values at the normalization conditions obtained respectively for each type of the film. This enables the exposure amount to be calculated at the same and constant conditions irrespective of variation of the film types or the processing changes. Only one kind software will suffice for the arithmetic operation on the exposure control.
The characteristics 15 for the exposure control may be obtained by correcting the density values 12 obtained from the measured data with the correction coefficients 13. A frame average density is used as the frame characteristics or DL j which will be calculated in accordance with the following equation (3). ##EQU3## In determining the printing conditions, if a section for setting the film characteristics is separated from a prior art system, the exposure may be controlled with the density value normalized by this invention method to automatically determine and administer the printing conditions.
FIG. 11 shows another embodiment of the normalization method according to this invention wherein the density values obtained from the photometric measurement 20 is normalized (21) thereby to obtain the characteristic 22 on a frame. The exposure amount 23 is calculated in correspondence to the characteristics 22 for the exposure control 24. The normalization steps comprise transforming the characteristic 22 into a nonnormalized frame characteristics 25, storing the transformed data in a memory 26 to obtain the normalized coefficients (or constants) 27, normalizing the density data obtained by the photometric measuring 20 in accordance with the above values and correcting the transformed data 25. The steps of coverting the measured data into the density data by logarithmic transformation and of normalizing the density data can be conducted simultaneously.
The number of the density divisions mentioned above may be more than two. If it is two, the averages of the characteristics can be obtained in the number of three to form two pairs of the correction coefficients each for the low density zone and the high density zone. Moreover, the divisions may be set at X 1 through X 4 as shown in FIG. 12 to make the density regions overlap continuously to be divided into the regions less than X 2 , from X 1 to X 4 , and more than X 3 . By setting a large number of density divisions, it becomes possible to estimate the shapes of the film characteristic curve, from which overexposed portion or underexposed portion can be controlled suitably. A density division may be a predetermined constant or an average of the characteristics obtained from the measured data, and preferaby set at a value to make the nhumber of data above and below the division substantially equal in number. It is desirable to be able to select or correct the data by eliminating abnormal values (such as low density, high density or data extremely out of the color balance) or setting a limit to obviate them so as to enable convergence of a small number of data into an average. An upper and a lower limits may be provided for stored data numbers (frame numbers (so that when it reaches the upper limit, average processing of the data should be started again from the beginning, and until it reaches the lower limit, the initially set value may be used rather than corrected value or the average of all the negative films including all types of the film may be used as a correction value. The correction value may be obtained for each type of the photographic materials (or onr as chosen to cover several types), averaging of data may be stored so that averaging process may be conducted once an order or once a day. Alternatively, the sum of characteristics may be stored in place of averages. The averaging process may be taken in this case at the time of switching printer channels at the beginning of an order.
FIG. 13 is a block diagram to show still another embodiment of the device to realize this invention normalization method in correspondence with the block diagram shown in FIG. 9. A conversion talbe 18 is prepared for normalization by using the data stored in the memory 14, the data in density obtained from the photometric measuring 10 are corrected (12), and the characteristics 15 for the exposure control are obtained based upon the correction. The photometric measuring 10 may be conducted twice; one each for calculation of the characteristics 11 on a frame and for correction (12) of the density values. Or the density values may be stored in a memory and corrected the stored data in the memory.
The effect of storage of frame characteristics at the memory 14 will now be described. As is widely known, almost all the frames of film are gray with slightly yellow greenish tint. It is possible to precisely produce the color by obtaining an average in LATD of a large number of film rolls. The result of experiments revealed, however, the values not necessarily in LATD but of other frame characteristics. Moreover, it was revealed that even if the area is divided into two; i.e. the densities more than the average and the densities less than the average, and the average is obtained once each for two frame characteristics, they show the same color. From such a finding, it was deducted that the film density may be normalized with the average of the frame characteristics of the two density areas. Frame characteristics are added (accumulated) at the data of the memory 14 and an average is obtained at the time of preparing the conversion table 18.
The conversion table 18 may be prepared as follows. The characteristics 11 obtained from the photometric measuring 10 are compared with the density division value which is preset, the accumulated data on a large number of frames having the characteristics larger than the value are designated as A j while those having the characteristics smaller than it are designated as B j . Using the relationship that j=1, 2, 3 or R, G, B, A j , B j or a combination thereof, the conversion table 18 may be prepared for data normalization. For example, if the measured data is D ij (i =number of measuring spots) and the corrected value as D' ij , a value for the optimum density balance and the gradation correction will be obtained by combining A j and B j . When the conversion table 18 is prepared for the normalization based on G out of the measured data on three primary colors, the values of D' i1 and D' i3 obtained by calculating D i1 and D i3 for "0" through "255" by the above formula (1) should be stored in the conversion table 18. When the conversion table 18 is prepared for normalizing the data on RGB based on a predetermined characteristic curve of the film, the above formula (2) should be relied.
As FIG. 14 shows, a curve is plotted for the average obtained from the stored data of R and B by referring to the reference or the average obtained from the stored data of G, from which is prepared a conversion table to transform the measured data on R and B into the measured data on G for normalization. The measured data on G do not have to be transformed by the conversion table, but are used as they are. By these normalization processing, the same object can be imaged on a negative film irrespective of the types of the photographic materials or developing processes.
The reference may be the measured data of (R+G+B)/3 as shown in FIG. 15. It may also be the data of (0.3X R+0.6X G+0.1X B )/10. Two or more of the RGB measured data may be combined suitably to be used as the reference. The cross marks in FIGS. 14 and 15 represent respective averages which are obtained by shifting R and B or R, G and B by a predetermined amount for the relationship between the color of the average and neutral color in the frame characteristics. The relation between the above two is not limited to the above, but may be otherwise included in calculation.
The conversion table 18 may be prepared in advance in the form of a table by calculating reference values for "0" through "255". In case the density division value is set at one point, the stored data larger or smaller than the point are obtained. This is a linear transformation. For instance, when a large number of measured data should be transformed, it may take lots of time if one of the equations of linear transformation (1) and (2) is to be applied to each of the measured data for two or three colors. Time can be shortened remarkably by using a conversion table. When the density division value is two or more in number, the transformation is nonlinear, and the conversion table may be prepared by linear interpolation or polyominal interpolation between the stored data. It is advantageous to use the conversion table rather than using a transformation formula in the speed of operation or degree of freedom allowable to non-linearity type.
Such a conversion table may be prepared at the time when a type of film is switched to another (channel switching), for one film roll, or for a predetermined amount of the stored data. It may also be prepared at the start of a work day for the channels to be used for the data based on the data accumulated by the preceding day. A magnification n (n= product by multiplication with 0.5-2.0) for each type of the film may be used as the reference value. The value of n is determined in advance. For example, n is set at 1.0 for the film of ASA 100 made by a manufacturer A while it is set at 1.12 for the film of ASA 100 by the manufacturer B. This enables elimination of the influence by the gradation of the film (γ-value). Further, a conversion table may be prepared by plotting "the data before conversion" -"reference value" at the vertical axis.
The density values 12 obtained from the measured data are corrected by referring to thus mae convesion table 18 to obtain the characteristics 15 for the exposure control. For obtaining the average density, a frame is divided into 12 cells each of which comprises the measurement points of 6×6=36. The average of a cell may be used as an average density data for storage. When the amount of data is small, this method is preferable as it achieves a higher precision over a wider density area than the case where a whole frame is processed as a single data. If the whole frame is treated as one data, it can not have a high density as it has been averaged and the number of densities is small. Each of the measured point may be stored in a memory, but this is not very effective as the averages do not become uniform even for a large number of data.
FIG. 16 shows another embodiment of this invention in correspondence with the one shown in FIG. 11. A conversion table 28 is prepared for normalization by storing in a memory 26 the data for transformation into frame characteristics before normalization. Density values of the photometric measuring 20 are normalized (21) in a manner mentioned above in accordance with the conversion table 28 and the converted data 25 are corrected at the same time.
The above statement was given in relation to the normalization process for the measured data or density data, but the process may naturally be applied for the frame characteristics or the exposure conrol characteristics. This invention method is remarkable in processing speed as respective meaured points do not need to be transformed.
The frame characteristics to be used for averaging may be the average density(s) of a whole frame or portions of a frame, weighted average, average density at selected point(s), the mean value between the maximum and the minimum densities, the average density of a main object or of background or a combination thereof. The abnormality or deviation detected at the development processing or the photometric meaurement device from the changes in averages or normalization coefficients may be displayed or outputted as an alarm to automatically correct or replace the developing agents and/or modify the printing conditions. Moreover, the difference in averages between photographic materials is used to detect the difference in the printing conditions between the photo-sensitive materials to automatically correct and control the exposure amount. Although description is given to the case of a negative film in the above statement, other types of film such as the reversal film or printed photographic paper may be used in this invention. This invention method is applicable to other types of copying materials (thermal, magnetic, or other types) or to an image display device.
This invention normalization method enables automatic normalization at a high speed for various types of film to be printed withput need for any reference film. This invention method can be applied to non-linear type of normalization to precisely conduct normalization for low density portions. This invention method further makes correct judgement of colors in objects imaged with an artificial light which often causes the under-exposed images to thereby enable highly precise control over the exposure. This invention method is further applicable to automatic control of variation in the developing process conditions, the emulsion numbers, the seasons or the devices.
It should be understood that may modifications and adaptations of the invention will become apparent to those skilled in the art and it is intended to encompass such obvious modifications and changes in the scope of the claims appended hereto. | The factors necessary for controlling photographic systems involve the photographic characteristics such as developing process characteristics which are subject to complicated interaction among various factors. Since it is difficult to measure and control such variable factor independently, situations involving such variations are preferably grasped comprehensively by a small number of criteria or values and controlled with a small number of values having high correlation with the variations. When gray image of an original film is photometrically measured at printing in three primary colors, the image densities in the colors are not uniform even with the same exposure and image density ratio is not uniform, either. This invention method enables optimum control of the photographic system by estimating the current photographic characteristics with the data up until the current spot, and further enables normalization of measured data at a high precision. | 6 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This is a divisional of application Ser. No. 10/899,979, filed Jul. 27, 2004 now U.S. Pat. No. 7,584,513, the entirety of which is incorporated herein by reference.
FIELD OF THE INVENTION
The present invention pertains to general cleaning devices and more specifically to snake and grapple devices for retrieving and cleaning hair clogs from sanitary drainpipes in sewer lines.
DESCRIPTION OF THE PRIOR ART
Many devices exist in the field of the present invention that fulfill countless objectives with respect to cleaning sewer lines and drainpipes. None however fulfill the need for a safe and inexpensive device that is compact and effective in retrieving hair clogs from the upper portions of drainpipes found in the average home which are connected to sinks, tubs and showers.
A common problem that plagues people that use modern plumbing is the inevitable development of clogs that develop in the drainpipes connected to sinks, bathtubs and showers. These clogs may result from objects accidentally being dropped down a drain, but more typically are the result of a build-up of the soaps, oils, greases, hair and other organic material that is washed down the drain. Individuals skilled in the art and even the average homeowner are familiar with devices and methods used to try to open clogged drains. These include flexible plungers, metal plumber's snakes and numerous chemical and biological substances readily available in supermarkets and hardware stores. Plungers use air and water pressure to push and pull at the clog to dislodge it and allow it to freely flow out of the pipe and into the sewer system. Snakes are typically coils of flattened metal with a spiral wire on the end that are inserted into the drain to break through a clog by forcibly pushing, pulling and twisting to mechanically degrade the clog and allow it to flow freely into the sewer system. Chemical liquids and crystalline sodas chemically react with the clog, degrading or liquefying it until it flows freely into the sewer system.
These devices are often effective in freeing clogged drains but do not offer a consistent solution to opening clogged drains that are largely a result of an accumulation of hair that typically occurs in the trap and especially hair that becomes entangled in the drain pop-up lever arm assembly just below the drain pop-up in the opening of the drain. The current invention departs from concepts and designs of the prior art by embodying a device that is compact and capable of reliably and effectively removing such hair clogs from the upper portions of drains.
Each device of the current art is seen to be deficient in providing a solution for these upper-drain hair clogs upon examination. Plungers that utilize air or water pressure to dislodge clogs in drains do not reliably dislodge hair clogs because the pressurized air or water force is not great enough to break hair away from solid, fixed protrusions within the drainpipe. The hair that is entangled around a fixed object primarily the drain pop-up lever arm is a case in point. In addition, the hair that has become embedded in encrustment or build-up that has accumulated within the pipe in the drain trap or along the pipe wall are additional examples.
The common plumber's snake is another device of the prior art that is effective in breaking up drain clogs by repeated forcible insertion and retrieval of the device in the drain. These however have the drawbacks of being large and unwieldy for the average homeowner and often cannot be used for upper-drain clogs or those occurring from the drain opening to the trap because the drain opening around the peripheral area of the drain pop-up of a sink is not large enough to accommodate the metal spiral end of the snake. Smaller spiral-tipped sink snakes are available but still very unwieldy and not adept at snagging hair entangled around the drain pop-up lever arm. In addition, most of these devices are metal and subject to rust and corrosion. Specialized upper-drain snake devices do currently exist in the prior art, and in the marketplace, which are designed to be small enough to fit past the drain stopper in the drain opening of the typical sink. These devices each have disadvantages not present in the present invention. They are either unsafe for the user because of sharp edges, or have wire hooks which can get hooked on the pop-up lever arm, or they are not compact making them inconvenient to store or transport. These devices usually have length and cannot be coiled in a stationary fashion, which means a homeowner cannot store them in a drawer or the artisan cannot transport then in a toolbox due to their length. This is also a disadvantage in commercial sale since these devices cannot readily be packaged with the shelf size drain products that they work hand-in-hand with to provide a complete drain cleaning solution. These devices also have fewer hair-snagging elements than the present invention reducing their ability to snag, and hold, drain hair by comparison.
Homeowners typically resort to caustic chemical products to open clogged drains. These are often effective in chemically “burning away” drain clogs but have the disadvantages of being dangerous to people, pets and the environment. The caustic ingredients in these remedies often contain sodium hypochlorite (bleach), sodium hydroxide (lye) or acid. These chemicals are responsible for a multitude of human poisonings annually as well as eye, lung and flesh injuries from their use and existence in the household. These chemicals are readily available in most all grocery and hardware stores and are the easiest for the homeowner to use. Consequently the large, cumulative volume that enters our sewage systems represents a hazard to the environment as the chemicals are not readily broken down in sewage treatment plants and flow out into the environment adding unwanted and detrimental pollutants. In addition, the chemical solutions often flow by hair clogs that are wrapped around the drain pop-up lever arm and are suspended in the center of the drainpipe where the liquids cannot effectively work on them.
Biological drain opening products are also readily available to homeowners in stores and also represent an easy-to-use drain maintenance solution for homeowners. They typically come in a liquid or powder form that the homeowner simply washes down the drain similar to chemical products. These solutions have the benefit of ease of use without the danger of injury to people, pets and the environment. They work by utilizing natural and harmless live bacteria and enzymes that feed on the organic drain refuse and break it down to base elements in the same way that nature recycles refuse in the environment. These types of products hold out the hope of effective drain maintenance for the individual diligent in home maintenance and family safety. They also represent a benefit to society by replacing the chemicals that cause injury to people and damage to the environment. Unfortunately one drawback of biological products is that they are less effective for rapid treatment of hair-clogged drains. By not being able to readily free slow flowing drains due to hair clogs, biological drain products are less popular in the marketplace and consequently consumers more frequently purchase the dangerous and harmful chemical products to open drains to the detriment of society in general.
The present invention plays a vital role in solving the societal problem of using injurious caustic chemical drain opener products. It fulfills the need for a compact device for effectively clearing drain hair clogs. As a stand-alone device it fulfills the need for a safe, effective and easily stowable device for a homeowner to immediately and easily open up a slow-running, hair-clogged drain by retrieving the hair clogs that often occur in them.
The present invention also fills a void that currently exists in the prior art by representing a device that enhances and facilitates the use of people-friendly and environment-friendly biological drain maintenance products. By providing a compact and inexpensive device for clearing the hair clogs that biological products do not effectively eliminate, the present invention can readily be packaged with these products making them a more effective and attractive solution to opening clogged drains without the societal problem of exposing people to dangerous chemicals and harming the environment. Nothing found in the prior art or the marketplace combines the attributes of compactness, safety to the user and hair-snagging effectiveness like that of the present invention.
Consequently, the present invention represents a substantial departure from all the current concepts and designs in the prior art and includes many novel features and embodiments resulting in a new device for cleaning hair clogs from drains.
OBJECTS AND ADVANTAGES
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially those skilled in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.
Accordingly, there are several objects and advantages of the present invention.
(a) It is an object of the present invention to provide a device for removing drain clogs that consist primarily of hair and other fibrous matter from the upper portions of drains from the drain opening to the trap where they typically form.
(b) It is another object of the present invention to provide a new and novel device for removing hair and other fibrous clogs from the upper portions of drains which combines attributes in a fashion that has not previously been anticipated, rendered obvious or even been previously implied by any of the crowded prior art of drain cleaning devices.
(c) It is also an object of the present invention to provide a device for removing hair and fibrous clogs that is easy and safe to use for both the average homeowner or artisan and which is inexpensive and affordable, and easily manufactured from existing products and materials.
(d) It is another object of the present invention to provide a device for removing hair and fibrous clogs from a drain that does not harm the environment or present a health hazard in the household or for the artisan.
(e) Another object of the present invention is to provide a device for removing hair and fibrous clogs that has a hair-snagging element at the distal end of an elongate shaft that is in the form of a pad which has width and thickness dimensions that allow it to fit into the drain opening through one of the four pie-shaped openings at the peripheral area of the drain pop-up stopper. This pad is not limited in shape but in the preferred embodiment of the device is manifested in the shape of a modified rectangle and made from readily available and inexpensive sections of the polymeric hook portion of hook-and-loop fastener material. The rectangular surface area of the hair-snagging pad has the end result of presenting the maximum number of hair-snagging hook elements on both the front and back side of the pad that the drain opening can accommodate. Hook-and-loop material is well known for its tenacious ability to snag and hold the loop portion of the fastener, providing the significant sheer strength or pull strength needed to pull loose and retrieve an entangled hair clog in a drain. Fibrous drain-hair clogs are similar in nature to this loop material and consequently also snag and hold tenaciously to the hair-snagging pad at the distal end of the present invention. The distinctive, rectangular shape of the pad has a wide sweeping range to snag hair when maneuvered and rotated within the drain. The hair-snagging pad in the preferred embodiment of the present invention utilizes the width of the flattened pad to present more hair-snagging hook elements against the clog and has an advantage over the prior art as stated in U.S. Pat. No. 5,836,032 issued to Hondo on Nov. 17, 1998. That device is not compact and is limited in the number of hooking elements presented to the clog since they are arranged radially around the elongate shaft which itself is limited in diameter to fit the largest circular dimension of the pie-shaped opening of the drain around the peripheral area of the drain pop-up stopper. The flattened hair-snagging pad of the present invention maximizes use of the widest lateral dimension of the drain opening rather than its smaller circular dimension. This consequently represents an advantage not contemplated in prior art providing a very effective device for removing hair clogs from drains while utilizing existing, inexpensive, tried-and-proven materials used in a new and novel way.
(f) Another object of the present invention is to provide a device for removing hair and fibrous clogs that is compact by having a construction that is capable of easily being bent and formed into pocket-sized, fixed shapes such as a coil. This has a distinct advantage in the field of specialized, upper-drain snake devices of being more easily stored, transported and packaged for sale either alone, in multiple quantities, or in combination with other related drain care products.
(g) It is another object of the present invention to provide a device for removing hair and fibrous clogs from a drain that can reduce the use of dangerous chemical drain openers and enhance the use of safe, biological drain cleaning products by being of such a compact size that it may be easily packaged with these safer types of off-the-shelf products.
(h) Yet another object of the present invention in its preferred embodiment is to provide a device for removing hair and fibrous clogs that has all exposed parts made from plastic materials and not subject to rust or corrosion like metal snakes, and which is capable of either being cleaned and reused or simply disposed of due to its low cost.
(i) Another object of the present invention is to provide a device for removing hair and fibrous clogs that due to its construction can be bent and remain fixed into many shapes. For the grasping, proximal end it may be formed for example into a circular, T-shaped or Z-shaped configuration to facilitate the pushing, pulling and rotating motion that is required to maneuver the hair-snagging distal end of the device into the drain and down to the fibrous clog.
(j) Another object of the present invention is to provide a device for removing hair and fibrous clogs that has exterior surfaces made from plastic materials which are free of sharp edges making it safe for the untrained user or artisan.
(k) Another object of the invention is to provide a device for removing hair and fibrous clogs that has effective hair-snagging ability without using metal hooks which tend to get snagged onto the drain pop-up apparatus within the drain when attempting to maneuver the device to snag hair clogs. Also, by utilizing polymeric hook-and-loop type material, the present invention is safer for the user than wire hook devices.
Further objects and advantages of the present invention will become apparent from a consideration of the drawings and ensuing description.
SUMMARY OF THE INVENTION
The present invention is a device for quickly retrieving hair and other fibrous waste from a drain without dismantling the drain and without using dangerous chemicals in the drain and which comprises an elongate shaft, which flexes into fixed bent positions, having a proximal end portion for grasping and a distal end portion for insertion into a drain. In the preferred embodiment, the shaft is comprised of a plastic sheathed metal wire, which maintains a fixed position when bent allowing the device to be shaped into compact designs for ease of storage, transport and packaging as well as allowing various shapes to be bent at the proximal end to serve as a grasping and rotating handle. The device also includes a hair-snagging member which is securely attached at the distal end of the elongate shaft which is a flat, double-faced pad or pouch made from attaching two strips of the hook portion of common hook-and-loop material back-to-back. The resulting pad or pouch may be of various sizes and shapes but, in the preferred embodiment, has a predetermined length and width, which is determined by the longest lateral dimension of the pie-shaped opening created along the side of the drain pop-up stopper. By exploiting the thinner but wider dimension of the drain opening, the present invention departs from devices of the prior art which typically provide hooking materials disposed radially from the smaller dimensioned circular shaft of the device. This novel use of common hook-and-loop material in a double-sided, modified rectangular shape maximizes the hooking member surface area allowing over 300 hooking members per vertical inch of pad to be presented against the drain hair-clog and creating a larger sweep circumference within the drain when the shaft and pad are rotated via twisting the grasping proximal end of the shaft. This multitude of hooking members efficiently snag drain hair and fibrous material since those elements are very similar in nature to the loop portion of hook-and-loop material, creating entanglement on contact with the clog and having the increased holding strength that is necessary to withdraw drain hair and fibrous matter which becomes tenaciously entangled around the drain pop-up mechanism and in the drain trap.
The objects and advantages of the invention will appear more fully from the following detailed description of the preferred embodiment of the invention made in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description. The description makes reference to the attached drawings wherein:
FIG. 1A is a perspective view of the preferred embodiment of this invention.
FIG. 1B is a perspective view of the preferred embodiment bent into a fixed coil shape showing its compact handheld size for storage and packaging.
FIGS. 1C-1E are top elevations showing the method of use of the preferred embodiment of FIG. 1A of the invention. The embodiments of FIGS. 2 , 3 , 4 A and 5 A would be operated in a similar fashion.
FIG. 1F is a perspective top view of a typical drain opening and pop-up stopper showing the pie-shaped drain openings and the optimum insertion angle for the invention.
FIG. 1G is a side sectional view of a typical drain and trap showing where hair clogs typically accumulate.
FIG. 1H is a cross-sectional close-up view of the elongated shaft of the preferred embodiment of this invention.
FIG. 1J is a close-up view of the plastic plug, which is inserted in the proximal end of the sheath covering of the elongated shaft of the preferred embodiment of this invention.
FIG. 1K is a close-up side elevation view of the hair-snagging pad showing the hooking members disposed at the distal end of the elongated shaft of all the embodiments of this invention.
FIG. 1L is a perspective view of another embodiment of this invention, which shows how the device may be made with an all-plastic shaft.
FIG. 2 is a perspective view of another embodiment of this invention, which shows how a quick-release catch mechanism is used to create a removable and disposable hair-snagging pad.
FIG. 3 is a perspective view of another very basic embodiment of this invention, which is simply a wire with a hair-snagging pad at the end.
FIG. 4A is a perspective view of yet another embodiment of this invention in which the basic wire version of FIG. 3 has a plastic-coated wire instead of a bare wire and the grasping end has a circular bend.
FIG. 4B is a close-up view of the proximal, grasping end of the embodiment shown in FIG. 4A , showing the method of operation utilizing the circular bend as a finger spin ring.
FIG. 5A is a perspective view of yet another embodiment of this invention showing the hair-snagging pad and wire shaft as disposable members with a removable handle.
FIG. 5B is a close-up end view of the embodiment of FIG. 5A showing the method of inserting and removing the disposable wire with pad member into the removable handle.
FIG. 5C is a close-up end view of the removable handle of the embodiment shown in FIG. 5A displaying the opening for inserting the wire shaft, and also showing the release button used for inserting and removing the wire shaft with pad.
FIG. 5D also shows the embodiment of 5 A but as a close-up sectional view of the end of the removable handle revealing the release mechanism inside in the locked position when the release button is not pushed.
FIG. 5E is also a close-up end view of the removable handle embodiment of FIG. 5A except with the release button pushed into the release position.
DETAILED DESCRIPTION OF THE INVENTION
The invention for removing hair and fibrous clogs from drainpipes is best understood by reference to the attached drawings.
Preferred Embodiment
FIG. 1 A
FIG. 1A shows a perspective view of the preferred embodiment of the invention. The shaft 10 of the device consists of a plastic sheath 16 made from common 3/16″ OD PVC plastic tubing with a 90 Shore A durometer hardness with a #16 galvanized wire 14 inserted inside. FIG. 1H is a sectional view of the shaft 10 perpendicular to the longitudinal axis of the shaft 10 . The shaft 10 may be of any length but in the preferred embodiment is approximately 61 cm or 24 inches to reach past the typical drain trap. The wire 14 is sealed inside the sheath 16 with a readily available plastic, barbed plug 18 in FIG. 1J that is inserted into the grasping, proximal end of the shaft. The wire 14 shown if FIG. 1H gives the device enough rigidity for pushing into drains. The distal end of the sheath 16 is heat-sealed into a flattened, bell shape (not shown) and inserted into the hair-snagging pad 12 shown in FIG. 1A . The hair-snagging pad 12 consists of two matching pieces of the hook portion of common hook-and-loop fastener material. The two pieces are fastened at the edges back-to-back into a pad or pouch 12 . The two pieces of hook material may be thermally attached, attached with adhesive or mechanically attached together with eyelets, rivets or similar fasteners (not shown). The flattened, distal end of sheath 16 is inserted into the pouch 12 and the pouch 12 is then sealed around the flattened, bell-shaped distal end (not shown) of the sheath 16 resulting in a pad 12 . The resulting pad 12 has hooking members 38 on both exposed, substantially flat surfaces of the pad 12 as seen in the side elevation view in FIG. 1K . The pad 12 may be many different shapes, colors and sizes but in the preferred embodiment is 15.88 mm by 25.4 mm or ⅝″ by 1″ and approximately shaped into a modified rectangle with approximately 300 hooking members 38 total on both sides of the pad 12 . This width dimension is maximized to fit the typical sink drain opening 26 which is often restricted by a pop-up stopper 28 as shown in FIGS. 1F and 1G , which is installed at the opening of the drain. As seen in FIGS. 1F and 1G , the pop-up 28 body segments the drain opening into 4 smaller, pie-shaped openings 30 . By designing the invention with a substantially flat, rectangular shaped snagging pad 12 , it is able to slide past the pop-up stopper 28 at an oblique insertion angle 32 with respect to the circumference of the drain opening as shown by the diagram in FIG. 1F .
Additional Embodiments
FIG. 1 L
FIG. 1L shows another, simplified embodiment of the present invention. This version maintains the novel features of being a compact device, and having a shaft 10 capable of being coiled along with a hair-snagging pad 12 , but is made even more inexpensively by having a molded plastic shaft 10 with grasping member 58 located at the proximal, grasping end, and the same unique hair-snagging pad 12 disposed at the distal end of the device. The hair-snagging pad 12 consists of two matching pieces of the hook portion of common hook-and-loop fastener material. The two pieces are fastened at the edges back-to-back into a pad or pouch 12 . The two pieces of hook material may be thermally attached, attached with adhesive or mechanically attached together with eyelets, rivets or similar fasteners (not shown). The molded plastic shaft has a T-shape (not shown) at the distal end, which is inserted into the hair-snagging pad 12 . This T-shape provides pull-out resistance from within the sealed pad or pouch 12 . The device in this embodiment is designed to be disposable after use and may be purchased economically in quantities for the home, institutional, or artisan user. The device as represented in this embodiment does not have a metal or wire core to maintain the fixed, coiled position necessary for ease of storage, transport and packaging. Consequently, it may also have a piece of the loop portion of common hook-and-loop material attached to the grasping member 58 to create a coiling fastener pad 60 such that when coiled by inserting through the grasping member 58 , and specifically through the coiling slot 62 , after 2 loops, the pad 12 wraps around and sticks to the attached piece of loop material and the device maintains a coiled configuration. The invention as represented in this embodiment may also be made from metal, however only for high volume, non-consumer users who are properly equipped with protective gloves due to the possibility of sharp edges and injury to the user.
Additional Embodiments
FIG. 2
FIG. 2 shows another embodiment of the present invention. This variation of the inventive device maintains the novel features of the preferred embodiment including a substantially flat, hair-snagging pad 12 and also a flexible shaft 10 which may be bent into compact fixed positions such as a pocket-sized coil. In this embodiment, the shaft 10 is made from molded plastic which may or may not have a wire core, and the hair-snagging pad 12 is sealed around the distal end of the male member of a catch mechanism 24 resulting in a pad 12 and catch 24 combined unit. The proximal end of the male catch 24 is snapped into a mating female member of the catch mechanism 22 which is molded into or attached to the distal end of the shaft 10 of the invention. The purpose of the mating catch mechanisms 22 and 24 is to provide a device for cleaning hair-clogs 36 ( FIG. 1G ) and other fibrous debris from a drain in which the hair-snagging pad 12 may be used and discarded with the retrieved debris. By releasing the catch 24 , the combined pad 12 and male catch 24 unit are freed from the device for disposal and ready for another new pad 12 and catch 24 unit to be snapped into place. It will be apparent after examining the drawing in FIG. 2 that equivalent functionality may easily be envisioned and implemented to serve the same purpose for the female catch 22 and male catch 24 . The depiction of these in the drawings shows a common buckle type snap-fit mechanism for illustrative purposes only to display the principle of the removable hair-snagging pad 12 , and are not intended to limit the invention to the exact construction and operation shown. It is the intent of the present invention to encompass other equivalent functioning embodiments of the female catch 22 and male catch 24 that satisfy the purpose of their functionality of easy removal of the pad 12 within the context of the present, novel invention.
Additional Embodiments
FIG. 3
FIG. 3 shows an additional embodiment of the invention. This embodiment is a stripped down version of the preferred embodiment, which may be manufactured even less expensively and may be desirable to the institutional user with many drains or the artisan who cleans drains professionally and has more interest in pure functionality than visual appeal. This embodiment consists of simply a #12, #14 or #16 size wire 14 or a plastic coated wire 14 with the attached hair-snagging pad 12 . The distal end of the wire 14 is bent into some shape that has shoulders perpendicular to the wire 10 shaft, such as an oblong O-shape or a T-shape (not shown) and is then sealed inside the pad 12 pouch thermally, mechanically or with adhesives. By bending the end of wire 14 , a shoulder is created which is perpendicular to the longitudinal axis of the wire 14 and which creates pull-out resistance of the wire 14 from the pouch 12 . The proximal end of the wire 14 is left unbent for the user to insert into a drill or to manually bend into various grasping shapes such as a crank, O-shape or T-shape.
Additional Embodiments FIGS. 4 A- 4 B
The embodiment of the invention shown in FIG. 4A is the same as described above in FIG. 3 except that the proximal grasping end of the wire 14 shaft is bent into a finger spin ring 46 loop which may act either as a grasping handle or a means to rotate the shaft by insertion of the finger in a stirring motion as noted below in the operational description of this embodiment and depicted in FIG. 4B . The finger spin ring 46 is created by bending wire 14 on the proximal end into an O-shape while leaving a length of extra wire at the proximal end for twisting back around the wire 14 shaft at the base of the finger spin ring 46 and then covering the lapped extra length of wire 14 (not shown) and wire 14 shaft with a wire lap cover 52 made from a piece of heat-shrink PVC plastic approximately 3.81 cm or 1.5 inches long.
Additional Embodiments
FIGS. 5 A- 5 E
FIGS. 5A-5E show another embodiment of the invention. In this form, the embodiment of FIG. 4 is taken one additional step by adding a removable handle 40 to the device as shown in FIG. 5A and utilizing a loop bend 56 as seen in FIG. 5B at the proximal end of the wire 14 for preventing the wire 14 with pad 12 combined member from pulling out of the handle 40 . The wire 14 may also be plastic coated. Once again this embodiment is targeted toward the professional artisan or institutional user who desires the same functionality of the preferred embodiment of the device, but regards per-use, reduced cost and utility of greatest importance. This embodiment retains the novel and effective double-sided snagging pad 12 and bendable memory of the wire 14 to coil the replaceable wire 14 with pad 12 combined members into a compact size for portability and packaging along with the handle 40 . The waterproof PVC sheath 16 and plug 18 of the preferred embodiment are not found in this version of the device since it will not optionally be cleaned and reused, but rather the wire 14 with pad 12 will simply be disposed of after use. The removable handle 40 is preferably made of molded plastic with a handle release mechanism 42 as shown in FIGS. 5C-5E into which the wire 14 is slid and automatically locked in place. The wire 14 receiving end of the handle 40 has a vertical lock slot 54 as viewed in FIG. 5C into which the looped end of the wire 14 is inserted after pushing release button 48 . FIG. 5C shows and end view of the handle 40 with the release button 48 in the out position. FIG. 5D shows a sectional end view of the handle 40 revealing the internal handle release mechanism 42 with the release button 48 in the out position. In this locked position, the loop bend 56 shown in FIG. 5B is unable to pull out through the smaller horizontal opening of the lock slot 54 . FIG. 5E is a sectional view of the handle 40 with the release button 48 in the pushed-in position. With the release button 48 pushed in as shown in FIG. 5E , the vertical opening of the lock slot 54 is revealed, allowing the loop bend 56 end portion of wire 14 to be inserted or withdrawn from the handle 40 . The wire 14 with pad 12 can be discarded after use.
The loop bend 56 in the wire 14 shown in FIG. 5B prevents the wire 14 shaft from spinning inside the handle 40 upon rotation of the device via the handle 40 . It will be apparent after examining the drawing in FIG. 5 that equivalent functionality may easily be envisioned and implemented to serve the same purpose for the removable handle 40 and handle release mechanism 42 . The depiction of these in the drawings are for illustrative purposes only to show the principle of the removable handle 40 and handle release mechanism 42 and not intended to limit the invention to the exact construction and operation shown. It is the intent of the present invention to encompass other equivalent functioning embodiments of the handle 40 and handle release mechanism 42 that satisfy the purpose of their functionality of a removable handle 40 and handle release mechanism 42 within the context of the present, novel invention.
Operation Common to All Embodiments
The device in its various embodiments as illustrated in FIGS. 1A , 1 L, 2 , 3 , 4 A and 5 A is used to retrieve hair-clogs 36 shown in FIG. 1G and other fibrous debris from the upper portions of drains from the drain opening to the U-shaped trap. The flexible shaft 10 allows the device to be bent into many shapes that aid in grasping, pushing, pulling and rotating the device to navigate the drainpipe and snag clogs. For example, if the device comes to the user packaged in a coil, the user may simply uncoil the needed length to reach the hair-clog and grasp the remaining O-shaped uncoiled shaft as a handle as viewed in FIGS. 1C-1D . The proximal end of the shaft may also be bent into a T-shape handle for the same grasping convenience. A third option might be to bend the grasping proximal end into a Z-shape crank (not shown) and use both hands to crank the device, rotating the pad 12 within the drain like a rectangular paddle, sweeping and entangling the drain hair and other fibrous clogs. The 300 odd hooking members 38 on both sides of the hair-snagging pad 12 will aggressively entangle and hold the hair for retrieval of the clog.
Additional Operation of Embodiment in FIG. 1 L
The embodiment of the device as represented in FIG. 1L operates in a very similar fashion to the other embodiments. The distal end of the device with the hair-snagging pad 12 is inserted into the drain and manipulated in an up and down or rotating motion to snag hair clogs 36 ( FIG. 1G ) suspended over the drain pop-up lever arm 34 or in the drain trap. This version of the device is simply held by the enlarged, molded plastic handle grasping member 58 located at the proximal end of the device while manipulating the device, or else the user's finger may be inserted in the hole of the grasping member 58 for pulling or rotation of the device.
Additional Operation of Embodiment in FIG. 2
The embodiment of the device as shown in FIG. 2 operates significantly the same as the embodiments illustrated in FIGS. 1A , 3 , 4 A and 5 A as noted above with the exception that this embodiment has a removable pad 12 with male catch 24 . After inserting, maneuvering, and withdrawing the device from the drain as stated above under operation common to embodiments in FIGS. 1A , 2 , 3 , 4 A and 5 A, the user simply pinches together the release arms of the male catch 24 to free the catch 24 and pad 12 for disposal along with the hair and fibrous waste retrieved from the drain. The user can then simply snap in a new, clean catch 24 with pad 12 unit. The shaft 10 with attached female catch 22 mechanism is purchased only once so that the user may buy the smaller and less expensive male catch 24 with pad 12 units in quantity for future drain maintenance.
Additional Operation of Embodiment in FIG. 3
In addition to the functionality described above under operation common to embodiments in FIGS. 1A , 2 , 3 , 4 A and 5 A, the embodiment of the invention as shown in FIG. 3 is designed to be purchased in quantities and disposable after each use. An optional mode of operation for this embodiment is to insert the proximal end of wire 14 into an electric drill for creating an automatic rotation motion of the hair-snagging pad 12 in the drain.
Additional Operation of Embodiment in FIG. 4 A
In addition to the functionality described above under operation common to embodiments in FIGS. 1A , 2 , 3 , 4 A and 5 A, the embodiment of the invention as shown in FIGS. 4A and 4B is designed to be purchased in quantities and disposable after each use. An optional mode of operation for this embodiment is to rotate the shaft 10 with pad 12 by use of the finger spin ring 46 . This allows the user to grasp the wire 14 lightly in one hand while inserting the index finger of the other hand into the ring 46 and rotating the whole device with a stirring motion of the finger along the inside surface of the ring 46 as shown in FIG. 4B .
Operation of Embodiment in FIG. 5 A
The embodiment of the device as shown in FIG. 5A is used to retrieve hair-clogs and other fibrous debris from the upper portions of drains from the drain opening to the U-shaped trap. As shown in FIG. 5A , this embodiment of the invention has a removable handle 40 that aids in grasping, pushing, pulling and rotating the device to navigate the drainpipe and snag clogs. The wire 14 and snagging pad 12 are slid into the removable handle 40 and locked into place with the handle release mechanism 42 shown in FIGS. 5D-5E . The handle is then grasped for the inserting, pushing and pulling of the device required to navigate the drain and snag and remove hair and other fibrous clogs. The rotating pad 12 within the drain acts like a rectangular paddle, sweeping and entangling the drain hair and other fibrous clogs encountered within the drainpipe. The 300 odd hooking members 38 as shown in FIG. 1K , on both sides of the hair-snagging pad 12 will aggressively entangle and hold the hair for retrieval of the clog. After use, the release button 48 on the handle 40 is pressed allowing the wire 14 with attached pad 12 to slide out and be thrown in the trash with the accompanying hair and other fibrous waste that is snagged. The user is then ready to insert a new, clean wire 14 with pad 12 into the reusable handle 40 . The handle is purchased only once and then the user need only buy the replacement wire 14 with attached pad 12 units in quantities for an inexpensive and convenient way to maintain drains on a regular basis. The operation of the handle release mechanism 42 will be apparent from viewing the drawings in FIGS. 5C-5E .
It is understood that the invention is not confined to the particular construction and arrangement of parts herein illustrated and described, but embraces such modified forms thereof as come within the scope of the following claims.
As can be seen from reviewing the drawings and descriptions above, the present invention in its various embodiments represent a new and novel device for retrieving hair-clogs and other fibrous debris from the upper portions of drains in the common household. Its advantages include:
Being hand-held in size due to its coiling capability making it compact for packaging, storing and transporting; Unique hair-snagging surfaces made from the hook portion of common hook-and-loop material which maximizes the number of hooking members due to its 2-sided substantially rectangular-shaped pad configuration; Safe for the user since it has no sharp edges or metal hooks; Safe for people, pets and the environment by opening hair-clogged drains without the use of caustic chemical drain openers; Compact enough to be packaged with off-the-shelf biological, drain-opener products creating a totally new combined product offering that is a complete drain maintenance solution without the environmental and safety issues of chemical drain products; Inexpensive to manufacture from commonly available materials; Inexpensive to buy due to low cost of manufacture; Made from corrosion-resistance materials.
As to a further discussion of the manner of usage and operation of the present invention, the same should be apparent from the above description. Accordingly, no further discussion relating to the manner of usage and operation will be provided.
With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.
Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention. | A compact, smooth surfaced, flexible and formable, elongate apparatus that has a hair-clog snagging end portion for insertion into drains for snagging and removing the common hair clogs that exist in the upper portion of drains typically around the drain pop-up mechanism and drain trap. The elongate shaft ( 10 ) may be bent along its complete length into any shape and remain fixed in that shape to accommodate compact storage as well as forming a grasping and twisting handle for the shaft while it is in the drain or bending the hair-snagging end of the shaft for easier insertion and navigation within the drain. The hair-clog snagging portion, which is at the distal end of the shaft, is in the form of a pad ( 12 ), which maximizes the surface area of hair hooking members ( 38 ). The hair-snagging pad consists of the hook portion of hook-and-loop fasteners and contains a multitude of miniature, hook formed, polymeric elements which aggressively entangle hair-clogs for quick retrieval from the drain without dismantling the drain and without using dangerous chemicals in the drain. | 4 |
FIELD OF THE INVENTION
[0001] This invention is in the field of pipeline construction safety devices and in particular the field of pipeline alignment instrumentation platforms for underground pipeline construction.
BACKGROUND OF THE INVENTION
[0002] The construction of underground pipelines, and in particular the construction of pipelines for the non-pressurized, gravity flow of wastewater with suspended solids, such as sanitary sewers and storm sewers, requires tight alignment and slope control. Such pipelines are typically constructed with a uniform pipe diameter, uniform slope and uniform alignment between manholes, with slope changes and alignment changes occurring at manholes only. The manholes are used for access for inspection, maintenance and cleaning of the pipeline. The uniform slope and alignment between manholes provides for the free flow of the waste water with the solids remaining in suspension and not settling out in the pipeline.
[0003] Modern construction techniques for such pipelines utilize a construction laser which emits a pinpoint laser beam on a selected alignment and slope for alignment and slope control as the pipeline is laid. The laser is simply mounted in the bottom of the manhole from which the next segment of pipeline is to be constructed. The laser must be adjusted to emit the laser beam on the alignment and with the slope desired for the construction of the next segment of pipeline which connects to the manhole. The horizontal alignment of the laser beam must be set based on reference to survey markers in place on the surface of the ground. While the construction lasers are self-leveling and therefore provide for simply dialing in the desired slope, the alignment of the laser must be surveyed in by reference to survey markers on the surface. The most commonly used method for aligning the laser is to position a surveying instrument known as a transit directly over the laser with the transit being above the surface of the ground with the survey markers in view. The transit can then be set on the proper alignment for the pipeline. With the pipeline trench dug away from the manhole a few feet thereby allowing the laser beam to be directed roughly in the direction of the desired pipeline alignment, the transit is rotated vertically from the desired alignment and the laser beam alignment is adjusted to match the alignment established by the transit. Thereafter, depending upon the soil conditions, the alignment can be checked as the pipe sections are laid and minor adjustments can be made to the laser alignment as the pipeline construction proceeds further away from the manhole. This can continue only so long as the pipe trench is not back filled as trench back filling will obstruct the view of the laser beam through the transit.
[0004] The manholes for sanitary sewer and storm sewer lines are generally constructed from pre-formed circular manhole sections which have an inside diameter of 4 feet, 5 feet or more. These manhole sections, which are usually several feet in height are stacked one upon the other on top of a manhole base. The number of manhole sections is dependent upon the depth of the pipeline at the manhole location. On top of the circular manhole sections, a manhole cone narrows the diameter of the manhole down to 2 ½ or 3 feet typically. On top of the cone, manhole rings are used to bring the manhole to the desired finish elevation, where the manhole cover is installed.
[0005] During the pipeline construction, typically the manhole sections are placed for a manhole up to the level where the cone would be installed. At this point, the transit that is used to align the laser for the next section of pipe is perched on tope of the manhole sections. This is accomplished by spreading the legs of the transit tripod placing them on top of the top manhole section, or placing a board or some other standing surface on top of the top manhole section, leaving an opening for the proper positioning of the transit over the laser. The transit operator is standing on some board on top of the manhole section at great safety risk to himself and others including particularly the workmen inside the manhole to adjust the laser.
[0006] An apparatus is needed that will improve efficiency and safety of the construction laser alignment procedure. Despite the inefficiency and obvious safety deficiencies of commonly used procedures, Applicant has found no prior art devices that are designed to address this need. U.S. Pat. No. 5,787,955 and U.S. Pat. No. 5,265,974 to Dargie disclose a safety net for a ground level hatch frame opening. U.S. Pat. No. 4,960,150 discloses a safety cover movable deck on tracks and rollers.
[0007] The objective of the present invention is to provide a movable platform which is mountable on the top of a manhole pipe section, providing a safer working surface for workmen for accessing the manhole to set up a pipeline construction laser and for setting up and operating surveying instruments for aligning the construction laser with the desired pipeline alignment.
SUMMARY OF THE INVENTION
[0008] The present invention is a safety platform for which a preferred embodiment comprises a platform deck, one set of four internal anchor pedestals for anchoring to the inside wall of a small diameter manhole section, another set of four external anchor pedestals for anchoring to the outside wall of a larger diameter manhole section, two opposing pairs of folding handrails with handrail anchor brackets securing the handrail sections to the platform deck, and four sets of safety barrier chains. For preferred embodiments, the platform deck is constructed of grating trimmed with structural angle. However, the platform deck can be constructed of plate material. Grating or plate material can be metallic, such as steel or aluminum, or non-metallic, such as fiberglass. The platform deck has an access opening which is likewise trimmed with structural angle to provide smooth edges for persons using the access opening. The access opening is positioned in the platform deck such that when the platform is positioned on the manhole the access opening outside edge is over the manhole inside wall and the manhole rungs, if there are any. This promotes easy access to the manhole from the platform deck and easy exit from the manhole to the platform deck. A pair of access cover rails is attached to the platform deck bottom, the access cover rail length typically being approximately twice the width of the access opening to allow for the access opening cover to be slid completely under the platform deck to an access position which provides for the access opening to be completely opened. Rail stop plates on each ends of the access cover rails confines the access cover to the access cover rails. Alternatively, tabs or other mechanisms can be used to confine the access cover to the rails. The distance between the access cover rails will generally be approximately equal to the length of the access opening since the length and width of the access cover will generally be approximately equal to the length and width of the access opening. This provides for a complete closure of the access opening when the access cover is in the closed position. A lock pin inserted through an upper lock pin opening in an upper lock pin collar, through the access cover and through a lower lock and opening in the lower lock pin collar secures the access cover in the fully closed or partially closed position. The upper lock panel collar and lower lock pin collar are welded to the top and bottom respectively of the access opening frame. A first handrail section and a second handrail section are anchored on opposing sides of the platform deck. The first handrail section is anchored to the platform deck by a pair of first handrail anchor brackets and the second handrail section is anchored to the platform deck by a pair of second handrail anchor brackets. The first handrail section and the second handrail section respectfully are secured in the upright position by a handrail lock pin inserted in anchor bracket lock pin holes in opposing anchor bracket side walls and handrail lock pin holes in opposing sides of each handrail post, the anchor bracket lock pin holes and the handrail lock pin holes have been aligned when the handrail is in the upright position a kick tab on the inside face of each anchor bracket prevents each bottom of each handrail post from rotating inward and hence the top of the handrail from rotating outward, hence providing stability to the handrail in the upright position with the locking pins in place.
[0009] The third handrail section and a fourth handrail section are likewise anchored on opposing sides respectively of the platform deck. The third handrail section and fourth handrail section are perpendicular to the first handrail section and the second handrail section. Handrail sections three and four lay flat on top of handrail sections one and two when the handrail sections are retracted to the transport position.
[0010] With the handrail sections all in the upright position the perimeter safety chains are connected between the respective handrail sections thereby creating a safety barrier completely around the perimeter of the platform deck. The perimeter safety chains are connected at each end to the outside edge of the handrail section by a chain bracket. Generally for enhanced safety, an upper perimeter safety chain and a lower perimeter safety chain are used between adjacent handrail sections.
[0011] The platform may also be equipped with optional features such as the lifting chain storage box built into the platform deck and typically equipped with a hinged cover. A section of the hinged lifting chain storage box cover may also be equipped with a battery anchor bracket which allows a battery to be secured to the platform deck for use in powering the pipeline construction laser as well as lighting or ventilation for use in the manhole or on the platform.
[0012] The present invention shown has two sets of anchor pedestals, a set of four interior anchor pedestals and a set of four exterior anchor pedestals. The two sets of anchor pedestals provide for the utilization of the platform on two different sizes of manholes. Screw anchors extend from the anchor pedestals to secure the platform to the manhole.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] [0013]FIG. 1 is a perspective top view of a preferred embodiment of the safety platform of the present invention with handrail sections in the upright position.
[0014] [0014]FIG. 2 is a perspective top view of a preferred embodiment of the safety platform of the present invention with handrail sections in the transport position.
[0015] [0015]FIG. 3 is a perspective top view of the access opening with access cover in the partially open, laser alinement position.
[0016] [0016]FIG. 4 is a perspective top view of the access opening with access cover in the open, access position and secured with lock pin in lock pin bracket.
[0017] [0017]FIG. 5 is a perspective top view of the access opening with access cover in the closed, safety position and secured with lock pin in lock pin bracket.
[0018] [0018]FIG. 6 is a top view of a preferred embodiment of the platform deck of the present invention, with anchor pedestal layout.
[0019] [0019]FIG. 7 is a perspective detail of first handrail anchor bracket.
[0020] [0020]FIG. 8 is a perspective detail of a third handrail anchor bracket with handrail in the upright position.
[0021] [0021]FIG. 9 is a perspective detail of a third handrail anchor bracket with handrail in the transport position..
[0022] [0022]FIG. 10 is a perspective top view of an embodiment of the chain storage box and storage box cover with battery bracket.
[0023] [0023]FIG. 11 is an elevation detail of inside anchor pedestals of the present invention.
[0024] [0024]FIG. 12 is an elevation detail of outside anchor pedestals of the present invention.
[0025] [0025]FIG. 13 is perspective top view of a chain storage box extended above the platform deck with battery bracket mounted in the chain storage box.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0026] Referring first to FIG. 1, this preferred embodiment of the safety platform 1 of the present invention shown comprises a platform deck 2 , two opposing pairs of folding handrails 5 affixed to the platform deck by handrail anchor brackets 6 , four sets of safety barrier chains 7 , and, referring now also to FIG. 6, one set of four internal anchor pedestals 3 , for anchoring to the inside wall 77 of a smaller diameter manhole section 78 , another set of four external anchor pedestals 4 for anchoring to the outside wall 79 of a larger diameter manhole section 80 . For the embodiment shown in FIG. 1 the platform deck is constructed of grating 8 trimmed with structural angle 9 . However, for other embodiments, the platform deck may be constructed of plate material. For those embodiments, the plate will likewise preferably be trimmed with structural angle to improve structural stability. The grating or plate may be made of steel, aluminum, fiberglass or other common structural materials.
[0027] The platform deck has an access opening 10 which for this preferred embodiment is likewise trimmed with structural angle 81 to provide smooth edges for those using the access opening. Referring again to FIG. 6, for this embodiment the access opening is positioned in the platform deck so that when the platform is placed on the manhole section, the access opening outside edge 11 is over the manhole inside wall 12 and the manhole rungs 13 , if there are any. This promotes easy access to the manhole from the platform deck and easy exit from the manhole to the platform deck. The access opening width 14 and access opening length 15 are selected to allow ease of access to and from the manhole. A pair of access cover rails 16 is attached to the platform deck bottom 17 . For this embodiment the access cover rails are constructed of structural angle. Referring also to FIG. 4, the access cover rail length is typically approximately twice the width of the access opening to allow for the access opening cover 18 to be slid mostly or completely under the platform deck to the access position 19 which provides for the access opening to be open. Rail stop plates 20 on each end 21 of the access cover rails confines the access cover to the access cover rails. Alternatively, tabs or other mechanisms can be used to confine the access cover to the rails. The distance 22 between the access cover rails will generally be approximately equal to the length of the access opening since the length 23 and width 24 of the access cover will generally be approximately equal to the length and width of the access opening. This provides for a complete closure of the access opening when the access cover is in the closed position 25 .
[0028] Referring to FIG. 4 and FIG. 5, a lock pin 26 inserted through a first lock pin opening 27 in first lock pin collar 28 and into the access cover grating secures the access cover in the closed position 25 . A lock pin inserted through a second lock pin opening 29 in a second lock pin collar 30 and into the access cover grating secures the access cover in the access position 19 . A lock pin inserted through the second lock pin opening in the second lock pin collar and into the access cover grating with the access cover in a partially open, laser alignment position 31 as shown in FIG. 3. The first lock pin collar and the second lock pin collar, are welded to the the access opening frame 33 . A lock pin tether 34 , as shown in FIG. 4 and FIG. 5, may be used to keep the lock pin handy for use at all times.
[0029] Referring again to FIG. 1, a first handrail section 35 and a second handrail section 36 are anchored on opposing sides of the platform deck. The first handrail section is anchored to the platform deck by a pair of first handrail anchor brackets 37 and the second handrail section is anchored to the platform deck by a pair of second handrail anchor brackets 38 . Referring now to FIG. 7 and FIG. 8, the first handrail section and the second handrail section respectfully are secured in the upright position 39 by a handrail lock pin 40 inserted in anchor bracket lock pin holes 41 in opposing anchor bracket side walls 42 and handrail lock pin holes 43 in opposing sides of each handrail post 44 , the anchor bracket lock pin holes and the handrail lock pin holes being aligned for the insertion of the handrail lock pin as shown in FIG. 8. When the handrail is in the upright position the bottom 45 of each handrail post extends downward into the anchor bracket recess 46 , which prevents the bottom of the handrail post from rotating inward 47 and hence the top 48 of the handrail from rotating outward 49 , thereby providing stability to the handrail in the upright position with the handrail lock pins in place.
[0030] A third handrail section 51 and a fourth handrail section 52 likewise are anchored on opposing sides respectively of the platform deck. The third handrail section and fourth handrail section are perpendicular to the first handrail section and the second handrail section for the embodiment shown in FIG. 1. A pair of third handrail anchor brackets 53 secures the third handrail section and a pair of fourth handrail anchor brackets 54 secures the fourth handrail section to the platform deck. For the embodiment shown in FIG. 1, the third handrail anchor brackets and the fourth handrail anchor brackets, which are shown in FIG. 9, are identical and the only difference between these handrail anchor brackets and the first or second handrail anchor brackets is that the third and fourth anchor brackets have bracket tabs 50 in the front face 55 of the brackets. For the embodiment shown in FIG. 1, when the handrail locking pins are removed and the handrail is lowered to the handrail transport position 56 as shown in FIG. 2 and in FIG. 7 and FIG. 9, the bracket tabs on the third and fourth handrail anchor brackets provide that, the handrail sections three and four will lay flat on top of handrail sections one and two, the height of the bracket tab being equal to the thickness 57 of the handrail.
[0031] Referring again to FIG. 1, with the handrail sections one, two, three and four in the upright position, the safety barrier chains 7 are connected between the respective handrail sections thereby creating a safety barrier 58 completely around the perimeter 59 of the platform deck. The safety barrier chains are connected at each end 60 to the outside edge 61 of a handrail section by a chain bracket 62 . Generally for enhanced safety, an upper safety chain 63 and a lower safety chain 64 are used between adjacent handrail sections. Other types of removable barrier elements may also be used between the handrail sections which will be known by persons skilled in the art.
[0032] The safety platform of the present invention may also be equipped with optional features such as a lifting chain storage box 65 shown in FIG. 1 and FIG. 2, which may inset into the platform deck, and lift rings 71 which are attached to the platform deck at the perimeter. The storage box may be equipped with a hinged chain storage box cover 66 as shown in FIG. 10. A section of the chain storage box cover may also be equipped with a battery anchor bracket 67 which allows a battery 68 to be secured to the platform deck for use in powering the pipeline construction laser as well as lighting or ventilation in the manhole or lighting for the platform. Alternatively, the top 82 of the chain storage box may extend above the top 83 of the platform deck as shown in FIG. 13, the depth of the chain storage box providing for the battery to be mounted and stored in the chain storage box with the battery anchor bracket 67 secured to the bottom 84 of the chain storage box. The lift rings are preferably equally spaced around the perimeter of the platform deck. The embodiment shown in FIG. 1 and FIG. 2 has four lift rings. At least three lift rings are ordinarily used in order to provide for stability in handling the safety platform.
[0033] Referring again to FIG. 6, the embodiment of the present invention shown has two sets of anchor pedestals, a set of four interior anchor pedestals 3 and a set of four exterior anchor pedestals 4 . The two sets of anchor pedestals provide for the utilization of the platform on two different sizes of manholes. For instance, the common inside diameter for sanitary sewer manholes is four feet. A less common but occasionally used inside diameter for sanitary sewers is six feet. The configuration of anchor pedestals shown in FIG. 6 works well for four foot and six foot diameter manhole combination. The interior set of four anchor pedestals fit inside of and provide for the centering of the platform on a four foot diameter manhole. Screw anchors 69 are extended from two of the interior pedestals to the inside wall 77 of the smaller diameter manhole 78 to secure the platform to the manhole. For the larger diameter manhole 80 , screw anchors are extended from two of the exterior pedestals to the outside wall 79 of the manhole.
[0034] For this embodiment the set of four exterior anchor pedestals 4 , which are illustrated in FIG. 12, are longer than the four interior anchor pedestals 3 , which are illustrated in FIG. 11, because the exterior anchor pedestals must fit on the outside 81 of the manhole section. Since the manhole sections typically have the side with the exterior joint groove oriented up, the anchor pedestals must extend below the exterior groove 70 as shown in FIG. 12. The screw anchors extend inwardly from two of the exterior anchor pedestals to the exterior surface of the manhole section below the joint groove in the top of the manhole section. While the embodiment shown utilizes four pedestals to position and secure the safety platform to a manhole, a three pedestal set could be used effectively, with only one of the pedestals having a screw anchor.
[0035] Other embodiments of the invention and other variations and modifications of the embodiments described above will be obvious to a person skilled in the art. Therefore, the foregoing is intended to be merely illustrative of the invention and the invention is limited only by the following claims. | A buried pipeline construction laser alignment survey platform mountable on manhole sections. The platform has a platform deck and two opposing sets of foldable handrail mounted on the perimeter of the platform deck which are inter-connected by safety chains to complete a safety perimeter. A manhole access in the platform deck has a slideable access cover providing for a closed set-up position, an open access position, and a partially open laser alignment position. One or more sets of anchor pedestals on the bottom of the platform deck provide for securing the platform to manhole sections of one or more diameters. | 4 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to object-shape coding apparatuses for coding a binary image representing an object shape by the unit of one rectangular block where the binary image is divided into a plurality of rectangular blocks, and particularly relates to an object-shape coding apparatus for coding rectangular blocks which includes both the pixels of the interior of the object shape and the pixels of the exterior of the object shape.
2. Description of the Related Art
In recent years, interest has been high in object-based coding schemes such as ISO/IEC 14496-2: “Information Technology-Generic Coding of Audio-Visual Objects-Part2: Visual.” The object-based coding divides an original image into the images of objects such as people or the like in the foreground and objects in the background, and attends to image coding with respect to each object image separately. The object-based coding can achieve a higher coding efficiency than coding schemes based on the coding of image frame units such as the MPEG-2 video coding standard (ISO/IEC 13818-2: “Information Technology-Generic Coding of Moving Pictures and Associated Audio Information: Video”). Further, use of object-based coding provides a basis for making of a video by combining objects.
An object image is comprised of texture images and object-shape data. In the object-base coding, therefore, both the texture coding and the shape coding are performed. Shape data includes binary data of shape information that only represents shape, and further includes multi-level data of shape information that represents object transparency. The present invention relates to the binary data of shape information.
In the following, related-art methods for binary shape coding will be described.
There are two types of methods for representing object shapes. One is to use a bit pattern image that has binary values representing whether pixels are inside or outside the object boundary, and the other is to show only the object boundaries. Accordingly, object-based coding apparatuses can also be classified into two groups, one for coding binary bit pattern images and the other for coding contour data.
Methods for coding binary bit pattern images attend to binary information coding by following the order of image scanning. Typical coding methods include the JBIG standard (ISO/IEC 11544: “Progressive Bi-level Compression”) and the MMR (modified modified read) coding standard (ITU-T T.6: “Facsimile Coding Schemes and Coding Control Functions for Group 4 Facsimile Apparatus”). The JBIG standard encodes binary data in a hierarchical manner by following the order of image scanning. The MMR standard encodes positions where binary pixels undergo changes in values, which is performed by following the order of image scanning. Both of these two coding methods are loss-less processes.
Methods for coding contour information attends to coding by following the order of points that make up the contour. Such methods include one that encodes directions of points that constitute the contour, and include one that reversibly encodes the coordinates of points that constitutes the contour. Among these, a chain coding scheme (Makoto Nagao, “Digital Image Processing,” Kindaikagaku, pp.384-385, 1987) assigns integers 1 through 8 to directions of connections relating the points that constitute the contour, and attends to reversible coding. Further, there is a method that carries out hierarchical coding by using the chain coding scheme (Tohru Kaneko, “Hierarchical Coding Scheme for Line Drawings Described by Chain Code Series,” The Transactions of the Institute of Electronics, Information and Communication Engineers, Vol. J69-D, No. 5, 1986).
Further, methods for coding contour information include approximating for the contour by using the Spline function (Myron Flickner, et al., “Periodic Quasi-Orthogonal Spline Bases and Applications to Least-Squares Curve Fitting of Digital Images,” IEEE Transaction on Image Processing, vol. 5, No. 1, pp. 71-88, January. 1996), and also include a method using Wavelet descriptors (George Muller, et al., “Progressive Transmission of Line Drawings Using the Wavelet Transform,” IEEE Transaction on Image Processing, vol. 5, No. 4, pp. 666-672, April 1996). Also included is a method that uses Wavelet descriptors for contour direction vectors (Japanese Patent Laid-open Application No. 11-255420).
All the binary shape coding methods as described above encode object shapes by the unit of one frame.
In general, texture coding is conducted by the unit of one rectangular block after an original image is divided into a plurality of rectangular blocks. Among texture information within a given rectangular block, information is useful where it corresponds to the area of the object defined by the shape data. In order to keep consistency between the texture coding and the shape coding, some shape coding schemes employ division of an image into a plurality of rectangular blocks, and attend to block-specific coding.
The binary shape coding of the MPEG-4 standard divides a binary shape image into a plurality of rectangular blocks (macro blocks) of 16×16 pixels where the binary shape image is comprised of shape interior pixels and shape exterior pixels, and attends to coding on the block-specific basis. The MPEG-4 standard is applicable to intra-frame coding as well as inter-frame coding. In the following, the intra-frame coding will be described.
In the intra-frame coding, a coding mode is selected based on the conditions of the rectangular block, i.e., based on whether all the pixels of the rectangular block are those of the shape interior, whether all the pixels are those of the shape exterior, and whether the shape interior pixels and the shape exterior pixels are both present inside the rectangular block. When all the pixels are shape interior pixels, or are shape exterior pixels, only the coding mode is transferred, without coding of each pixel. When the shape interior pixels and the shape exterior pixels are both present, a coded word is assigned to each pixel through arithmetic coding.
The arithmetic coding is a type of a variable length coding scheme that reduces the quantity of information by utilizing disparity of symbol occurrence probabilities. In this coding scheme, a probability line segment is segmented according to the probabilities of occurrences of a symbol series, and a binary decimal value indicative of a position within a segmented section is used as a code for the symbol series (Hiroshi Harashima, “Image Information Compression,” Ohm, pp. 153-161, 1992.7). In the arithmetic coding, segmentation of a probability line based on probabilities of occurrences of a symbol series can be consecutively made through arithmetic operations, which achieves a compression efficiency that is close to the entropy limit of the symbol series.
The Huffman coding is known as a variable length coding scheme that reduces the quantity of information by utilizing inequality of symbol occurrence probabilities in the same manner as in the arithmetic coding (Hiroshi Yasuda, Hiroshi Watanabe, “Basics of Digital Image Compression,” Nikkei BP Publishing Center, pp. 32-35, 1996). In the Huffman coding, one coded word is assigned to one symbol. Since the Huffman coding only requires reading a coded word for a given symbol from the coded word table stored in memory, a coding apparatus can be implemented as a small size apparatus.
As described above, the MPEG-4 arithmetic coding has macro blocks of 16×16 pixels as input thereto, and attends to consecutive segmentation of a probability line segment for 256 pixel symbols. In general, coding efficiency increases as the processing block becomes bigger, but an increase in the processing block size entails needs for increased computation and increased memory. This is one of the factors that make it difficult to develop a real-time coding apparatus for an image of a large size such as an HDTV image.
In order to reduce the computation load and the memory volume, input data may be coded by the unit of a small data size. Since real-time processing is performed by use of hardware, however, correlation within the data cannot be fully utilized if the coding is performed by the unit of a small data size. In order to obviate this problem, it is desirable to provide a coding apparatus that can achieve efficient coding while avoiding an increase in the size of hardware for code assigning process.
Accordingly, there is a need for an object-shape coding apparatus that can achieve efficient coding while avoiding an increase in the size of hardware for code assigning processing where the object-shape coding apparatus divides a binary image representing an object shape into a plurality of rectangular blocks, and encodes each of the rectangular blocks separately, including a rectangular block which includes both object interior pixels and object exterior pixels.
SUMMARY OF THE INVENTION
It is a general object of the present invention to provide a coding apparatus and a coding method that substantially obviate one or more of the problems caused by the limitations and disadvantages of the related art.
Features and advantages of the present invention will be set forth in the description which follows, and in part will become apparent from the description and the accompanying drawings, or may be learned by practice of the invention according to the teachings provided in the description. Objects as well as other features and advantages of the present invention will be realized and attained by a coding apparatus and a coding method particularly pointed out in the specification in such full, clear, concise, and exact terms as to enable a person having ordinary skill in the art to practice the invention.
To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides an apparatus for coding a binary image representing an object shape, the apparatus including an inferior symbol detecting unit which decides which one of binary zero and binary one is an inferior symbol that is of smaller occurrence within a given area of the binary image, a divided portion generating unit which divides a rectangular block of the given area into divided portions, a map information generating unit which generates map information for each one of the divided portions, the map information indicating whether a corresponding one of the divided portions has the inferior symbol included therein, and a coding unit which encodes only the divided portions that have the inferior symbol included therein, wherein an identification of the inferior symbol, the map information, and the encoded divided portions are output from the apparatus.
The coding apparatus as described above divides a binary rectangular block that includes object interior pixels and object exterior pixels, one of which is inferior to the other in terms of frequency of occurrence, and the divided portions are encoded only when there is an inferior symbol included therein, thereby achieving efficient coding of the binary image representing an object shape.
Further, the coding apparatus as described above reduces the load of the coding process while avoiding an efficiency reduction caused by data division, thereby making possible the real-time coding of a large shape image such as an image having the size of an HDTV image.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of an object-shape coding apparatus according to the present invention;
FIG. 2 is an illustrative drawing showing a macro block having both inferior symbols and superior symbols and divided in half in both the vertical direction and the horizontal direction;
FIG. 3 is a block diagram of another embodiment of the object-shape coding apparatus according to the present invention, which includes a unit that identifies an inferior symbol for each small block;
FIG. 4 is an illustrative drawing showing an example of a bit pattern of a small block;
FIG. 5 is an illustrative drawing showing a bit pattern of a small block in which pixels are circularly shifted in the horizontal direction relative to the bit pattern of FIG. 4 ; and
FIG. 6 is an illustrative drawing showing pixel line map information having bits M 1 through M 8 that correspond to the horizontal direction pixel lines L 1 through L 8 of FIG. 5 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the following, embodiments of the present invention will be described with reference to the accompanying drawings.
Before engaging in the describing of embodiments, the principle of the present invention will be described briefly.
In the description that follows, pixels that are either interior pixels within the object boundary or exterior pixels outside the object boundary are defined as inferior symbols if they are those of smaller occurrence between the two types of pixels within the macro block, whereas the pixels of greater occurrence between the two types of pixels are referred to as superior symbols.
Pixels that represent an object shape have relatively high correlation therebetween, so that the inferior symbols or the superior symbols tend to be concentrated. Since the superior symbols are defined as those outnumbering the inferior symbols, there may be a case in which all the data within a divided portion are superior symbols. In the present invention, data indicative of whether at least one inferior symbol exists within the divided portion or indicative of whether all the data within the divided portion are superior symbols is transferred as a structural representation. (Hereinafter, this data is referred to as map information.) Use of map information as a structural representation makes it possible to eliminate a need for coding a divided portion comprised only of the superior symbols. This achieves an improved coding efficiency.
In the present invention, a macro block is divided into a plurality of smaller blocks according to a predetermined procedure, and the obtained smaller blocks are further divided into pixel lines (lines of pixels) in the horizontal or vertical direction, thereby providing two stage data division. At each stage of data division, map information for divided data is transferred. The second stage division is not performed if the divided data obtained at the first stage include only superior symbols.
A coded word is assigned to a bit pattern of a divided pixel line by using a variable length coding. In the present invention, pixels are rearranged first according to a predetermined rearrangement procedure such as placing inferior symbols at the beginning of a pixel line, and, then, the rearranged bit pattern is coded and transferred. In this case, information about the data rearrangement needs to be additionally transmitted. Since the rearrangement improves the efficiency of variable length coding, however, the overall coding efficiency is also improved.
In this manner, the present invention divides shape data along with use of structural representations, and assigns coded words. Namely, data division provides a basis for a simplified coding process, and use of the structural representation achieves highly efficient coding.
FIG. 1 is a block diagram of an object-shape coding apparatus according to the present invention.
In FIG. 1 , the object-shape coding apparatus includes an inferior symbol detecting unit 1 , a small block generating unit 2 , a block map detecting unit 3 , a pixel-line direction checking unit 4 , a pixel-line generating unit 5 , an in-line-pixel rearranging unit 6 , a pixel-line map coding unit 7 , a pixel-line coding unit 8 .
In the following, operations of the object-shape coding apparatus will be described.
As input signals to the coding apparatus, the inferior symbol detecting unit 1 receives a rectangular macro block which includes object interior pixels as well as object exterior pixels. The inferior symbol detecting unit 1 outputs a macro block bit pattern that represents an image by two statuses, i.e., the inferior symbol defined as that of lesser occurrence between the interior pixels and the superior pixels in the macro block and the superior symbol defined as that of greater occurrence in the macro block. Further, the inferior symbol detecting unit 1 supplies information about the inferior symbol, which is transmitted along with coded data.
Each pixel of the macro block input to the apparatus of the present invention is either an object interior pixel or an object exterior pixel. In the following description, blocks and pixel lines are described as being a bit pattern having two statuses, i.e., the inferior symbol status and the superior symbol status.
The macro block bit pattern supplied from the inferior symbol detecting unit 1 is input to the small block generating unit 2 , which outputs a plurality of small blocks of bit patterns generated by dividing the macro block. The present invention is not limited to a particular method of dividing a macro block into small blocks. As an example, as shown in FIG. 2 , a macro block having both inferior symbols and superior symbols may be divided in half in both the vertical direction and the horizontal direction, thereby generating four small blocks.
The plurality of small blocks of bit patterns supplied from the small block generating unit 2 are input to the block map detecting unit 3 , which outputs block map information indicative of whether an inferior symbol is present in each small block. This block map information is transmitted along with coded data. If there is an inferior symbol in a given small block, the bit pattern of this given small block is also output from the block map detecting unit 3 .
FIG. 3 is a block diagram of another embodiment of the object-shape coding apparatus according to the present invention which includes a unit that detects the inferior symbol for each small block.
When the configuration of FIG. 3 is compared with the configuration of FIG. 1 , the configuration of FIG. 3 has a small-block-inferior-symbol detecting unit 9 newly added between the block map detecting unit 3 and the pixel-line direction checking unit 4 . Other elements are identical to those shown in FIG. 1 . In FIG. 3 , the same elements as those of FIG. 1 are referred by the same numerals, and a description thereof will be omitted.
The small-block-inferior-symbol detecting unit 9 receives the bit pattern of a small block from the block map detecting unit 3 , and outputs information about the inferior symbol of the small block and the bit pattern of the small block that is represented by two statuses, i.e., the inferior symbol of the small block and the superior symbol of the small block. These outputs are supplied to the pixel-line direction checking unit 4 .
In what follows, the operation of the small-block-inferior-symbol detecting unit 9 will be described with reference to the four small blocks shown in FIG. 2 .
Small blocks B 1 and B 4 shown in FIG. 2 have an inferior symbol of the small block that is identical to the inferior symbol of the macro block. With respect to these two blocks, the small-block-inferior-symbol detecting unit 9 thus outputs the bit pattern of the small block as it was received, without any change, together with the inferior symbol information of the small block. In small block B 3 , the inferior symbol of the small block is the superior symbol of the macro block. With respect to the small block B 3 , therefore, the small-block-inferior-symbol detecting unit 9 outputs the inferior symbol information of the small block, and outputs a bit pattern in which the inferior symbols and the superior symbols are switched within the small block B 3 .
The bit pattern of the small block, which is output from the block map detecting unit 3 in FIG. 1 or supplied from the small-block-inferior-symbol detecting unit 9 , is input to the pixel-line direction checking unit 4 . The pixel-line direction checking unit 4 outputs information indicative of a direction of a pixel line, i.e., either the vertical direction or the horizontal direction, which is transmitted together with the coded data. The information indicative of a pixel-line direction may be defined and provided for each macro block, or may be defined and provided for each small block.
Controlling factors as to which one of the vertical direction or the horizontal direction is selected as a pixel-line direction are not limited to particular implementation in the present invention. In this embodiment, the controlling factor is the number of lines in which an inferior symbol is present, and the direction is selected such as to make the number of lines smaller than otherwise. In the case of a bit pattern of a small block as shown in FIG. 4 , for example, there are five horizontal pixel lines that include an inferior symbol, whereas eight vertical pixel lines (all the vertical lines) include an inferior symbol. The horizontal direction that has the smaller number of lines is thus selected.
The bit pattern of the small block and the information indicative of a pixel-line direction are supplied from the pixel-line direction checking unit 4 to the pixel-line generating unit 5 . The pixel-line generating unit 5 outputs a plurality of pixel lines of bit patterns generated by dividing the small block into the pixel lines. The bit patterns of the pixel lines are supplied to the in-line-pixel rearranging unit 6 , which outputs pixel rearrangement information and the bit patterns of pixel lines in which pixels are rearranged as specified by the pixel rearrangement information. The pixel rearrangement information is transmitted together with the coded data. The pixel rearrangement information may be defined and provided for each macro block, or may be defined and provided for each small block.
In the following, the rearrangement operation of the in-line-pixel rearranging unit 6 will be described.
In this embodiment, a bit pattern of a pixel line is circularly shifted by the rearrangement processing, and the shift length is used as the rearrangement information. This aspect of the present invention will be described with reference to FIG. 4 and FIG. 5 .
For the sake of explanation, it is assumed that the bit pattern of the small block shown in FIG. 4 (the pixel lines as indicated as Y 1 through Y 8 ) is input to the in-line-pixel rearranging unit 6 . The pixels lines in the horizontal direction are subjected to circular shifting to the left by two samples, so that the order of columns X 1 , X 2 , X 3 , X 4 , X 5 , X 6 , X 7 , and X 8 are changed to X 3 , X 4 , X 5 , X 6 , X 7 , X 8 , X 1 , and X 2 . This produces a bit pattern as shown in FIG. 5 . Pixel lines L 1 through L 8 in the horizontal direction shown in FIG. 5 respectively correspond to the pixel lines Y 1 through Y 8 in the horizontal direction shown in FIG. 4 .
In FIG. 5 , the inferior symbols concentrate on the left-hand side in each horizontal pixel lines. In this embodiment, variable length codes are structured by assuming the situations in which inferior symbols concentrate near the beginning of each pixel line (i.e., the left portion of a horizontal pixel line or the top portion of a vertical pixel line). If such rearrangement processing results in a decrease in the volume of codes generated by coding, the shift length “2” indicating the shift by 2 samples is transmitted as the rearrangement information together with the coded data. Further, the bit pattern of FIG. 5 after the rearrangement processing is supplied to the pixel-line map coding unit 7 .
If the intended rearrangement processing results in an increase in the volume of codes generated by coding, the rearrangement processing is not actually performed, and the shift length “0” is transmitted as the rearrangement information together with the coded data. Further, the bit pattern of FIG. 4 as it is as received as input signals is supplied to the pixel-line map coding unit 7 .
The pixel-line map coding unit 7 receives the pit patterns of bit lines from the in-line-pixel rearranging unit 6 , and outputs pixel line map information that indicates pixel lines in which an inferior symbol is present. Further, the pixel-line map coding unit 7 outputs the bit pattern of a pixel line with respect to each pixel line that has an inferior symbol included therein. The pixel line map information is a series of bits that are provided as many as there are pixel lines, and indicate whether an inferior symbol is present in respective pixel lines. This information is coded by variable length codes such as Huffman codes.
In what follows, the operation of the pixel-line map coding unit 7 according to this embodiment will be described.
For the sake of explanation, it is assumed that the bit patterns of the horizontal direction pixel lines L 1 through L 8 as shown in FIG. 5 are supplied to the pixel-line map coding unit 7 . FIG. 6 shows pixel line map information having bits M 1 through M 8 that correspond to the horizontal direction pixel lines L 1 through L 8 of FIG. 5 . In this embodiment, the bits M 1 through M 3 of FIG. 6 indicate that the respective pixel lines L 1 through L 3 include only superior symbols, and the bits M 4 through M 8 of FIG. 6 indicate that the respective pixel lines L 4 through L 8 each include at least one inferior symbol. In this manner, the pixel-line map coding unit 7 according to this embodiment outputs the pixel line map information as shown in FIG. 6 and the bit patterns of the horizontal pixel lines L 4 through L 8 as shown in FIG. 5 in which at least one inferior symbol is present.
The pixel line map information and the bit patterns of horizontal pixel lines having an inferior symbol included therein are input to the pixel-line coding unit 8 . The pixel-line coding unit 8 assigns codes to the bit patterns, and the obtained coded data is transmitted to a decoder side.
As described above, the apparatus of this embodiment receives the small block of FIG. 4 representing a partial object shape, and assigns codes to the line bit patterns M 4 through M 8 of FIG. 6 .
According to the present invention described above, a binary rectangular block in which object interior pixels and object exterior pixels are both present are easily and efficiently coded.
Further, the present invention reduces the load of the coding process while avoiding an efficiency reduction caused by data division, thereby making possible the real-time coding of a large shape image such as an image having the size of an HDTV image.
Further, the present invention is not limited to these embodiments, but various variations and modifications may be made without departing from the scope of the present invention.
The present application is based on Japanese priority application No. 2000-322696 filed on Oct. 23, 2000, with the Japanese Patent Office, the entire contents of which are hereby incorporated by reference. | An apparatus for coding a binary image representing an object shape includes an inferior symbol detecting unit which decides which one of binary zero and binary one is an inferior symbol that is of smaller occurrence within a given area of the binary image, a divided portion generating unit which divides a rectangular block of the given area into divided portions, a map information generating unit which generates map information for each one of the divided portions, the map information indicating whether a corresponding one of the divided portions has the inferior symbol included therein, and a coding unit which encodes only the divided portions that have the inferior symbol included therein, wherein an identification of the inferior symbol, the map information, and the encoded divided portions are output from the apparatus. | 6 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an improved Universal Multiple Angle Work Piece Holder which is capable of setting an object at any desired compound angle so that the object may be machined at any desired location. The invention further relates to an apparatus which can be securely adjusted in a manner that provides a firm support for the object to be machined and provides an angle adjustment design which allows the object to be machined to be adjacent the center lines of the Universal Multiple Angle Work Piece Holder. The present invention also relates to a tool which can easily be converted into other useful tools such as an indexing head to set a work piece at standard angles, a collet holder for use with machines such as a vertical milling machine or a surface grinder, or a dresser for use with a grinding wheel.
2. Description of the Prior Art
In general, the present invention relates to tools which are commonly known as swivel vises. A swivel vise is a tool which is capable of being rotated through a series of pivotally connected members such that the object which is held by the tool can be set at any desired compound angle. Since the general coordinates which are set by this tool are spherical coordinates, the tool is also known as a 3-way angle vise.
The general concept of the swivel vise or 3-way angle vise is known in the prior art. U.S. Pat. No. 2,432,058 issued to Wiken et al. for a Machine Tool discloses a tool holder which comprises a base member adapted to be adjustably clamped on the work table of a conventional surface grinder; a vise unit or tool clamp proper, adapted to present the work to the wheel; and a plurality of intermediate support units or swivel members which provide a universally adjustable mount for the tool holder. By reason of the number of units employed, it is possible to set up any compound angle by adjusting the members individually to the components of the angle or to the individual angles locating the surface to be ground. Although the general concept of the swivel vise or 3-way angle vise is disclosed in the Wiken patent, the elements of the tool are fit together in a fashion such that they form cantilever arms. As a result, the object which is held and worked on is well off center. This presents several major problems. First, the presence of the grinding wheel or other machine tool working on the object sets up a substantial bending moment on the plurality of intermediate support units which are connected to each other in a pivot or beam like fashion. As a result, it is very easy for the tool to break in one of several locations under normal stress conditions created by the grinding wheel or other operating machine. Second, since the object to be operated on is held well off center, any slight change in any of the intermediate support elements throws the entire set angle off and the entire set of intermediate support elements must be readjusted to achieve the new desired compound angle. This results in a time consuming operation. In addition to the above mentioned defects, the tool disclosed in the Wiken patent has thin bolts interconnecting each part. This, accompanied by the substantial beam like interconnecting design, makes the vise design inherently weak, resulting in a tool which can easily break at numerous different points.
U.S. Pat. No. 2,444,727 issued to Bush discloses a tool whose principal object is to provide a support for a vise, clamp or other work holding medium, adapted to be affixed to a table or bench and which consists of superimposed, cylindrical elements, the upper of which constitutes or carries the work holding means and is capable of rotative and oscillative displacement with respect to the lower and supporting cylindrical element, in different positions thereon throughout a range of 180 degrees about a horizontal axis and 360 degrees on an axis perpendicular to said horizontal axis. As disclosed in FIG. 1, the design of the moving elements are inherently very weak. In both the upper and lower cylinders, the 180 degree movement is achieved by loosening one set screw and rotating the cylinder by the desired amount. This is an extremely weak adjustment and can easily slip if any transverse force is imparted to the object being machined. Since one small screw has to hold all of the cylinders and take the compound force from the machine, this tool can easily break or become bent at numerous locations along the length of the one screw.
U.S. Pat. No. 2,390,428 to Disse discloses a swivel vise which once again enables a piece of work supported by the vise to be presented in substantially any position to a cutting element. As shown in the various figures, especially FIGS. 1, 4, and 6, the design has many of the same inherently weak features as the Wiken patent. The moving elements are locked by small screws and are separated by significant lengths such that forces imparted to one end of an element are multiplied by the bending moment along the length of a member. It is therefore extremely easy for a screw to slip under the heavy pressure imparted to the object held and being worked on by the operating machine such as a milling machine. This could necessitate costly reworking of a part. The inherently weak design also has a lot of areas where parts of the tool can break.
U.S. Pat. No. 3,680,268 issued to Lorton discloses a swivel vise tool which has many of the same inherently weak features of previous swivel vise designs discussed above. As shown in FIGS. 6, 7 and 8, each element is locked in place by a small screw and has a significant length along which a bending moment from a transverse force at one end can be multiplied. As with the Wiken design, the object to be worked on is off center and a slight movement in one element necessitates readjusting all of the elements. Therefore, as with the other prior art tools, it is easy for an element to move during operation thereby ruining the object being worked on. Further, due to this inherently weak design, there are numerous areas where a part of the tool can break under stress.
A more primitive form of multiple angle vise is disclosed in U.S. Pat. No. 1,414,970 issued to Nelson. An example of a very complex universally adjustable multi-angle tool for workholders is disclosed in U.S. Pat. No. 2,509,338 issued to Elliott et al. This is an extreme example of a tool with multiple shaft elements which provide numerous weak areas at the multiple joints where the tool can break under stress. Once again, the object being held is well off center and any slight adjustment requires readjusting most of the elements of the tool. Both of these patents disclose movement performed by means of a crank.
Finally, U.S. Pat. No. 4,140,307 issued to Dalmau et al. is another example of a multiple angle vise wherein rotation to different compound angles is achieved through a multiplicity of ball and socket arrangements.
Therefore, all of the prior art designs for swivel vises or 3-way angle vises have weak interconnecting means which can cause an adjustment to slip thereby ruining the part being held and worked on. All of the prior art designs also have inherently weak designs because of the beam like interconnections which serve to set up numerous high stress areas resulting from the force imparted to the object being worked on.
In addition to the above enumerated common defects, the prior art tools also disclose arrangements wherein each desired element of the compound angle must be individually set, with no rapid adjustment to set commonly used angles such as 30 degrees, 45 degrees, 60 degrees and 90 degrees. Further, the designs disclose an arrangement wherein the part being worked on is substantially off center. Therefore, a minor adjustment in one of the elements usually necessitates readjusting everything. Therefore, the designs in the prior art necessitate a time consuming adjustment process to achieve the desired compound angle and a time consuming readjustment process if any modification in a setting is required.
In addition to the above common defects, the prior art tools do not disclose any features which would enable the tool to be converted into any other tool such as an indexing head, a collet holder or a dresser.
SUMMARY OF THE PRESENT INVENTION
The present invention incorporates a novel and nonobvious design for a Universal Multiple Angle Work Piece Holder which creates a very strong tool that can withstand a substantial transverse, vertical, or multidirectional force imparted to the object being held by the work piece holder from a tool such as a vertical milling machine, a surface grinding machine or a drill press. The present invention also incorporates a novel design for a multiple angle work piece holder which permits the object or work piece being held and worked on to be substantially along the three axis centerlines of the work piece holder and adjacent the center of gravity of the work piece holder so that a required angle adjustment can be made with ease and not require time consuming resetting of all of the movable elements of the tool. This feature in conjunction with the unique design of the rotating shafts of the work piece holder assures that substantial transverse forces applied to the work piece will not be multiplied by any long distance to a joint or other area of the work piece holder to create a bending moment. The present invention also incorporates a novel means for rapidly setting commonly used angles such as 30 degrees, 45 degrees, 60 degrees and 90 degrees so that the desired compound angle can be rapidly produced. The present invention also incorporates a novel design which permits the tool to be converted from a multiple angle work piece holder to several other useful tools such as an indexing head, a collet holder for use with machines such as a vertical milling machine or a surface grinder, or a dresser for use with a grinding wheel.
It has been discovered, according to the present invention, that if the cylindrical shafts along which the Universal Multiple Angle Work Piece Holder rotates are thick relative to the length and the entire diameter of the swivel member being rotated, the inherent design of the tool is such that no swivel member is substantially off center. As a result, no swivel member is formed as a beam along which a substantial bending moment can be imparted from the forces generated by the operating tool such as a surface grinder. This design crates a tool of superior strength which is able to withstand substantial forces from any compound angle direction.
It has also been discovered, according to the present invention, that if the rotating swivel members of the Universal Multiple Angle Work Piece Holder are designed such that the object being held is adjacent the three axis centerlines of the tool and also in line with or adjacent the center of gravity of the tool, minor changes in compound angles can be easily achieved without the necessity of resetting all of the angles in great detail. This design also lends strength to the tool and enables it to withstand substantial forces from the operating tool since the forces are concentrated adjacent the center of gravity of the Universal Multiple Angle Work Piece Holder.
It has further been discovered, according to the present invention, that if the base of the Universal Multiple Angle Work Piece Holder is designed so as to incorporate a vertical member which acts as the tool's main support, the tool can easily be converted into a multiplicity of other useful tools such as an indexing head, a collet holder, or a dresser.
It is therefore an object of the present invention to provide a Universal Multiple Angle Work Piece Holder which is capable of setting an object at any desired compound angle so that the object may be machined at any desired location.
It is another object of the present invention to provide a Universal Multiple Angle Work Piece Holder which has an inherently strong design that avoids having any of the rotating or swiveling members substantially off center to thereby avoid a substantial bending moment to occur which would allow the tool to break at numerous locations.
It is a further object of the present invention to provide a Universal Multiple Angle Work Piece Holder which is designed so that the object being held is substantially along the three axis centerlines of the tool and also in line with or adjacent the tool's center of gravity, to thereby allow for a firm support to withstand substantial forces and to also permit easy adjustment to alternative compound angle settings.
It is still another object of the present invention to provide a tool which can rapidly and easily be converted into a multiplicity of other useful tools such as an indexing head, a collet holder and a dresser.
Further novel features and other objects of the present invention will become apparent from the following detailed description, discussion and the appended claims, taken in conjunction with the drawings.
DRAWING SUMMARY
Referring particularly to the drawings for the purpose of illustration only and not limitation there is illustrated:
FIG. 1 is a perspective view of the Universal Multiple Angle Work Piece Holder looking from the left side.
FIG. 2 is a partial cross-sectional view taken along line 2--2 of FIG. 1.
FIG. 3 is a perspective view of the first swivel member of the Universal Multiple Angle Work Piece Holder looking from the left.
FIG. 4 is a perspective view of the second swivel member of the Universal Multiple Angle Work Piece Holder looking from the left.
FIG. 5 is a partial rear view of the first swivel member looking from line 5--5 of FIG. 3.
FIG. 6 is a cross-sectional view taken along line 6--6 of FIG. 1.
FIG. 7 is a cross-sectional view taken along line 7--7 of FIG. 1.
FIG. 8 is a perspective view of the present invention looking from the left side after it has been converted into an indexing head, collect holder and dresser.
FIG. 9 is a partial cross-sectional view taken along line 9--9 of FIG. 8.
FIG. 10 is a cross-sectional view taken along line 10--10 of FIG. 8.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to the drawings of the invention in detail and more particularly to FIG. 1, there is shown at 10 the preferred embodiment of the Universal Multiple Angle Work Piece Holder. As shown in the perspective view looking from the left of FIG. 1, the tool consists of four interconnected components which are movably and rotatably interconnected. The first component is a base member 20. The base member 20 has two lengthwise edges 21 and 23 respectively and two widthwise edges 25 and 27. The base member 20 also contains an upper surface 29. The base member 20 includes means through which the base member 20 can be removably attached to a surface such as a bench, table, or the worktable of a machine such as a vertical milling machine, surface grinding machine, or drill press. As shown in FIG. 1, the attachment means are recesses 22 and 24 on opposite sides 21 and 23 of the lengthwise edges of the base member 20. The recesses 22 and 24 extend through the entire thickness of the base member 20. Attachment members such as bolts (not shown) can be passed through recesses 22 and 24 and used to attach the base member 20 to a bench, table, or worktable of a vertical milling machine, or drill press.
Rigidly attached to the upper surface 29 of the base member 20 and integral therewith is a support member 30. Referring to FIG. 6 as well as FIG. 1, the support member 30 has an upper portion 32 and a lower portion 34. Both portions have a common vertically disposed flat forward face 36 and a vertically disposed rearward face 38 as shown in FIG. 6. This rearward face 38 extends radially outward. The upper portion 32 has a curved upper surface 31 in the shape of a 180 degree arc. The lower portion 34 has two substantially vertically disposed sides 33 and 35 respectively. The support member 30 is designed to be short, compact and thick relative to the base 20, in order to provide a strong supporting means. The lower portion of rear face 38 of support member 30 is substantially parallel to the rear widthwise edge 25 of the base 20, and is positioned so as to be approximately centered along that widthwise edge. The support member 30 contains a transverse cylindrical hole 40 which extends through the entire thickness of support member 30 and having its axis disposed in a substantially horizontal direction. The horizontally disposed cylindrical hole 40 is located at approximately the midpoint of the upper section 32.
Located along one vertically disposed side 33 is a horizontally disposed recess 42. As shown in FIG. 1, the recess 42 extends through rearward face 38 but does not extend as far as the forward face 36. The lower portion 34 also contains a horizontally disposed cylindrical hole 44 which is substantially parallel to recess 42 but spaced apart from it by a portion of the support member 30. The partial cross-sectional view of FIG. 2 shows the relationship of the horizontally disposed cylindrical hole 44 to the recess 42. The horizontally disposed cylindrical hole 44 accommodates a movable rod 46 which can slide within the hole 44. The hole 44 extends through the entire thickness of the support member 30 and therefore the rod 46 can protrude through the forward face 36 or the rearward face 38. The rod 46 is tightened by means of a transverse headed bolt 48. The tip 50 of the transverse headed bolt 48 passes through a channel 52 between the cylindrical hole 44 and the recess 42, and abuts the rod 46 to thereby tighten it in place. The rod 46 can therefore be permitted to move in a horizontal direction so that its forward position can protrude through the forward face 36 of the support member 30 and its rearward portion can protrude through the rearward face 38 of the support member 30. The diameter of the rear portion of rod 46 is reduced so that it can fit into holes in an indexing head.
The upper surface 29 of the base member 20 contains a groove 28 which extends inwardly from its forward face 27 and is spaced apart from the forward face 36 of support member 30.
The curved upper surface 31 of support member 30 contains a degree scale 37 of 180 degrees, with 0 at the uppermost portion of upper section 32 and the scale extending for 90 degrees in either direction.
A perspective view of the first swivel member 60 is shown in FIG. 3. First swivel member 60 is of one piece construction but contains four very distinct sections; first section 62, second section 70, third section 80 and fourth section 90. The first section 62 is a horizontally disposed solid cylinder containing a flat rear face 64 and a flat front face 66 (not shown). As shown in FIG. 6, first section 62 contains a threaded internal cylindrical opening 68 which extends inwardly from rear face 64. The threaded internal cylindrical opening 68 can accommodate the threaded shaft of a bolt.
The second section 70 is a horizontally disposed solid cylinder whose diameter is greater than the first section 62 but whose thickness is substantially less than the first section 62. Second section 70 has a rear face 72 and a front face 74. The rear face 72 of second section 70 is integral with the front face 66 of first section 62 such that both sections share a common horizontal axis. As shown in FIG. 6, central transverse hole 40 in support member 30 is designed to accomodate first section 62 of first swivel member 60. When so inserted, the circumference 71 of second section 70 is parallel to the upper arc surface 31 of support member 30. The central portion of front face 74 contains a concave surface 73 while the balance of front face 74 is substantially flat. First swivel member 60 is locked inside support member 30 by a threaded bolt 78. The bolt 78 is screwed into a disc 76 which abuts the outwardmost portions of rear face 38 of support member 30. The threaded bolt is screwed into threaded internal cylindrical opening 68 of first section 62. A gap 77 is left between the disc 76 and the rear face 64 of first section 62. This gap 77 is required in order to assure that first swivel member 60 can be tightened properly.
As shown in FIG. 5, the rear face 72 of said second section 70 contains a multiplicity of inwardly extending holes 75 positioned at various degrees from the horizontal such as 30 degrees, 45 degrees, 60 degrees and 90 degrees. The holes are designed to be aligned with and accommodate the protruding forward end of rod 46. Through this combination, the first swivel member 60 can be quickly rotated relative to the support member 30 to a commonly used angle such as 30, 45, 60 or 90 degrees and quickly locked in place by use of the headed bolt 48 sliding the forwardly protruding end of rod 46 into the appropriate hole.
Third section 80 is also a solid cylinder whose axis is substantially perpendicular to the common axis of first section 62 and second section 70. One portion of the circumference 82 of third section 80 is rigidly attached to the concave portion 73 of front face 74 of second section 70. The cylindrical third section 80 contains a substantially flat front face 84 and a substantially flat rear face 86. Third section 80 is attached to second section 70 such that rear face 86 is substantially parallel to one portion of the circumference 71 of second section 70.
Fourth section 90 is also a solid cylinder which extends from the front face 84 of third section 80. Fourth section 90 and third section 80 share a common axis. The fourth section 90 contains a front face 94 and a rear face 96. The rear face 96 is attached to front face 84 of third section 80. The front face 94 contains a threaded cylindrical opening 92 which can accommodate the threaded shaft of a bolt.
In an alternative embodiment, first swivel member 60 can be made of two piece construction. In this embodiment, first section 62 and second section 70 are of one piece construction and third section 80 and fourth section 90 are of one piece construction, and they are joined at the locations of the second section 70 to the third section 80 as described above by means 91 shown in phantom in FIG. 4.
A perspective view of second swivel member 100 is shown in FIG. 4. Second swivel member 100 is of one piece construction but contains three distinct sections; fifth section 102, sixth section 110, and seventh section 120. Fifth section 102 is a torroidal cylinder whose outer diameter is substantially the same as the outer diameter of third section 80. The interior of fifth section 102 contains a central opening 103 which is designed to accommodate the cylindrical fourth section 90 of first swivel member 60. In the embodiment shown, the front face 104 of fifth section 102 contains a recess 105. This recess accommodates a disc 107 (shown in FIG. 7). The disc 107 contains a central opening 109. As shown in FIG. 7, fifth section 102 is movably connected to fourth section 90 by threaded bolt 108 which is passed through cylindrical opening 109 in disc 107 and thread through threaded cylindrical opening 92 in fourth section 90. When so joined, the rearward face 106 of fifth section 102 abuts the front face 84 of third section 80 and also encircles fourth section 90 which is thereby contained within fifth section 102. Bolt 108 abuts the forward portion of disc 107 which is parallel to the front face 104 of fifth section 102. The circumference 111 of fifth section 102 contains a degree scale 113 adjacent its rear face 106. The scale is divided into 360 degrees with 0 located at the upper portion when the axis of fifth section 102 is horizontal. In an alternative embodiment, the disc 107 can be eliminated and that portion is contained within a solid portion of fifth section 102.
Rigidly attached to the circumference 111 of fifth section 102 and adjacent its front face 104 is sixth section 110. Sixth section 110 is a mating member which joins fifth cylindrical section 102 to seventh cylindrical section 120.
Seventh section 120 is a solid cylinder whose axis is approximately perpendicular to the axis of third section 80 and fifth section 102. When the axes of the latter two sections are horizontally disposed, the axis of seventh section 120 is vertically disposed. Seventh section 120 contains a substantially flat lower face 122 and a substantially flat upper face 124. Fifth section 102 and seventh section 120 are joined by sixth section 110 such that a portion of the circumference 126 of seventh section 120 is substantially parallel to the front face 104 of fifth section 102. Seventh section 120 extends over all of fifth section 102 and a portion of third section 80. Seventh section 120 contains a deep cylindrical recess 128 which begins at upper face 124 and extends through most of the thickness of seventh section 120.
As shown in FIG. 1, FIG. 6 and FIG. 7, third swivel member 130 is a solid cylinder which contains an upper face 132 and a lower face 134. Integral with lower face 134 and extending from it is a substantially cylindrical stem 136 which flares slightly outwardly along its lower portion. The cylindrical stem 136 is accomodated by the deep recess 128 in seventh section 120. Lower face 134 in eighth section 130 thereby abuts upper face 124 in seventh section 120. The outer diameter of both sections is substantially the same. The circumference 133 of third swivel member 130 contains a degree scale 155 which has 360 degrees marked on it. Third swivel member 130 can thereby rotate within seventh section 120. Third swivel member 130 can be held rigid by means of a transverse screw 138 which extends through a threaded opening 139 in seventh section 120. The tip of the transverse screw abuts the surface 131 of cylindrical stem 136.
The holding member 140 which grips the object being worked on is rigidly attached to the upper face 132 of third swivel member 130 by means of screws (not shown) or other comparable means. In FIG. 1, the holding member 140 shown is a slide table. This can be replaced by numerous other gripping members such as a vise.
The above description is very detailed. Described in more general terms, the present invention is a Universal Multiple Angle Work Piece Holder 10 for positioning a work piece holding member 140 and work piece held therein above a flat supporting surface at any selected angular position in each of three planes. The work piece holder 10 comprises a flat base member 20 adapted to rest upon a flat supporting surface and a support member 30 fixedly secured to one edge of said base member 20 and extending vertically upward therefrom. The work piece holder 10 further comprises a first swivel member 60 positioned beside said support member 30 and containing a first shaft or cylinder 62 extending parallel to said base member 20 and rotatably supporting the first swivel member 60 from the support member 30. The first swivel member 60 is spaced a sufficient distance above the base member 20 so as not to directly engage the base member 20 when rotated upon first shaft 62. The work piece holder 10 further comprises a second swivel member 100 disposed partially along a parallel plane with said first swivel member 60 and partially extending above said first swivel member 60 and substantially above the horizontal center of said base member 20. The first swivel member 60 further contains a second shaft or cylinder 90 perpendicular to said first shaft 62 and rotatably supporting said second swivel member 100. A third swivel member 130 is secured to the outer extremity of said second swivel member 100 which is remote from said first swivel member 60. Said third swivel member 130 also contains a shaft 136 extending perpendicular to said second shaft 90 and within said second swivel member 100 such that said second swivel member 100 rotatably supports said third swivel member 130 from said second swivel member 100. There are circular scale markings associated with said support member 30 and with said second and third swivel members respectively for indicating the respective position settings thereof.
Finally, there are means carried by the outer extremity of the third swivel member 130 for securely supporting the work piece holding member 140 and associated work piece contained therein, whereby the work piece holding member 140 and work piece contained therein may be selectively supported at any three-dimensional angular position relative to said base member 20 and when thus supported is positioned above the approximate center of gravity of the work piece holder 10.
The present invention incorporates a unique design wherein the shafts or cylinders about which the various components rotate are relatively thick in diameter as compared to their length. This provides a very strong rotating support which does not have the inherent weaknesses of prior art multiple angle tools. There are no relatively long dimensions between rotating joints (where two rotating components come together) which permits a bending moment force to be imparted to a joint by means of the force imparted to the workpiece held by the work piece holding member 140 by the tool such as a vertical milling machine, surface grinding wheel, or drill press.
Another unique feature of the design of the present invention is that the rotating members, namely the first, second and third swivel members are aligned relative to each other such that the workpiece held by the work piece holding member 140 is positioned at or near the centerlines of the Universal Multiple Angle Work Piece Holder 10 and above the approximate center of gravity of the work piece holder 10. Therefore, the present invention can easily absorb far greater forces imparted from the moving tool. Furthermore, it can readily accommodate adjustments of one rotating element without the necessity for extensive realigning of all three swivel members. For example, in Wiken U.S. Pat. No. 2,432,058, the entire tool is hinged off center. Any change requires extensive changes in all components. In the present invention, the object being worked on is adjacent the tool's centerlines, so a change of one component doesn't require extensive changes in all of the angular components.
In the preferred embodiment, the dimensions of the various components of the Universal Multiple Angle Work Piece Holder 10 are as follows. It is emphasized that these are approximate dimensions and furthermore are for illustrative purposes and in no way are intended to limit or restrict the spirit or scope of the present invention. In the preferred embodiment, the outer diameter of the main cylinders will all be the same and will be approximately three and one-quarter (31/4) inches. The main cylinders and diameters are: the diameter of the upper section 32 of support member 30, and the diameter of second section 70 and third section 80 of first swivel member 60, the diameter of fifth section 102 and seventh section 120 of second swivel member 100, and the diameter of third swivel member 130. As previously pointed out, the diameters of the rotating shafts will be relatively thick compared to their lengths. For first section 62 of first swivel member 60, the outer diameter will be approximately one and three-quarter (13/4) inches while its length will be approximately one and five-eighths (15/8) inches. For fourth section 90 of first swivel member 60, the outer diameter will be approximately one and one-half (11/2) inches while its length will be approximately one and one-eighth (11/8) inches. The outermost diameter of stem 136 will be approximately two (2) inches while its thickness or height will be approximately three-quarters (3/4) of an inch. The height of support member 30 from the base 20 will be approximately three and five-eighths (35/8) inches. The depth groove 28 in base 20 will be approximately two hundred thousands (200/1000) of an inch. The height of sixth section 110 at the shortest distance between the fifth section 102 and seventh section 120 will be approximately three-eighths (3/8) of an inch. By way of example only, the base 20 can be three-quarters (3/4) of an inch thick and six (6) inches square.
In operation, the work piece is held by work piece holding member 140 which is fixed to the upper surface 124 of third swivel member 130. Any desired compound angle for spherical coordinates can be set so that the work piece can be presented to the machine at the desired angle. With standard X-Y-Z coordinates, one vertical or Z-X coordinate is set by rotating second section 70 the desired amount as indicated on the degree scale 37 along surface 31 of support member 30. As previously mentioned, commonly used angles such as 30, 45, 60, or 90 degrees can be set by using the holes 75 in second section 70 and rod 46 in the support member 30. Also, the dimensions are such that third section 80 and fifth section 100 will pass within groove 28 of the base member 20 at their maximum extension. The first section 62 of first swivel member 60 is then tightened by bolt 78.
The second vertical or Z-Y coordinate is set by rotating fifth section 100 relative to third section 80. The rotating cylinder which is fourth section 90 is loosened by means of bolt 108 and after the desired angle is achieved, the bolt 108 is then tightened. The measurement is taken along degree scale 113 along surface 111 of fifth section 100. A "0" marker is positioned on the surface 82 of third section 80 to indicate relative rotational movement.
Finally, the horizontal or X-Y coordinate is set by rotating third swivel member 130 by the desired amount. This section is permitted to rotate by loosening transverse screw 138 and then tightening it after the desired rotation has been achieved.
Due to the inherent design exemplified by the dimensions previously set forth, the work piece held by the work piece holding member 140 can be positioned at any angle but still is positioned close to the centerlines or axes of the Universal Multiple Angle Work Piece Holder 10 and also adjacent its center of gravity lines. Further, the dimensions of having a substantial diameter rotating member (sections 62, 90 and 136) and large diameter relative to their length provides a very strong tool since there are no elongated sections along which a substantial bending moment can be set up from the force generated by the working tool on the work piece. Further, the compact design with abutting sections approximates a sphere and further increases the strength and durability of the Universal Multiple Angle Work Piece Holder. The present invention can be manufactured out of steel or any other strong metal such as titanium, or any other durable alloy.
The Universal Multiple Angle Work Piece Holder 10 can be used in conjunction with a multiplicity of tools such as a vise. The vise would be supported by the third swivel member 130 and would be in place of the slide table 140 shown in FIG. 1. In terms of rotational movement, the tool can be used to rotate the vise to any desired compound angle. By way of example, the rotation in the Z-X axis could be one-half of a sphere, the rotation in the X-Y axis could be one-half of a sphere, and the rotation in the Z-Y axis could be one-quarter of a sphere. The vise, in turn, would be used to grip the product being worked on and presented to the operating machine.
The Universal Multiple Angle Work Piece Holder is also a tool holder and is designed to hold tools for grinding down a grinding wheel, or to shape a tool for cuts on a milling machine. The slide table 140 in FIG. 1 can be replaced with many different types of tool holders.
Another unique feature of the present invention is the ability to quickly and efficiently convert the tool 10 from a multiple angle work piece holder into several other useful tools such as an indexing head, a collet holder and a dresser. Examples of this conversion feature are shown in FIG. 8, FIG. 9 and FIG. 10.
The tool is converted by removal of first swivel member 60 from support member 30. This automatically removes second swivel member 100 and third swivel member 130, thereby leaving only the base 20 and the attached first support member 30. The tool can be converted into an indexing head 144 as follows. A hollow shaft 146 is placed through hole 40 in support member 30. The front end of the shaft contains a wider diameter collar 148 which abuts the front face 36 of support member 30. The rear end of the shaft 146 can be threaded to accommodate a threaded indexing wheel 150. The indexing wheel 150 can abut the outwardly protruding portion of rear face 38 of support member 30. The indexing wheel 150 has a multiplicity of holes 152 which correspond to all of the standard degrees such as 15, 30, 45, 60, 75, 90 etc. The object to be worked on is held within the shaft 146 and can be quickly rotated to any of the desired degree angles corresponding to the holes 152 in the indexing wheel 150. For convenience, handle member 160 can be attached to the indexing wheel 150, to assist in ease of turning the object to the desired degree. As shown in FIG. 8 and in the detailed cross-sectional view of FIG. 9, rod 46 in support member 30 can now be used to protrude through rear face 38 in support member 30 and to fit into a corresponding one of the holes 152 so that the object to be worked on is set at the appropriate angle. The rod is once again moved into place by transverse headed bolt 48. This assures rapid indexing at appropriate angles for work pieces held in this manner.
The tool can also be used as a collet holder 170 by insertion of the collet or chuck 172 into hollow shaft 146. A rear face plate 174 is screwed onto the threaded end 171 of the collet 170 to hold it firmly in place. For convenience, the indexing wheel 150 and handle member 160 can be used in conjunction with the collet holder 170, as shown in FIG. 8. Through this combination, the indexing wheel 150 can be used in conjunction with the collet or chuck 172 so that the collet holder 170 can be rapidly rotated to the desired preset angles and then quickly set by use of rod 46 placed into the appropriate one of holes 152. The gripping end 173 of collet or chuck 172 protrudes through the front face 147 of wider diameter collar 148. The collet holder 170 can be used to preset any desired object to be held within the collet 172 to any machine such as a vertical milling machine, a surface grinding machine or a drill press.
Finally, the above tool can be converted into a dresser for use in grinding or sharpening tools such as a grinding wheel. The dresser 180 consists of dresser shaft 182 which is held within collet 172 and a diamond cutter 184, held at the protruding end of dresser shaft 182. The grinding wheel is thereby placed against the diamond cutter 184 to thereby sharpen it.
The unique design of the base 20 and support member 30 therefore permit easy conversion of the tool 10 into a multiplicity of other useful tools for use with machinery commonly found in a machine shop.
Of course, the present invention is not intended to be restricted in any particular form or arrangement, or any specific embodiment disclosed herein, or any specific use, since the same may be modified in various particulars or relations without departing from the spirit or scope of the claimed invention hereinabove shown and described of which the apparatus and methods shown are intended only for illustration and for disclosure of an operative embodiment and method of manufacture and not to show all of the various forms of modification in which the invention might be embodied or manufactured.
The invention has been described in considerable detail in order to comply with the patent laws by providing a full public disclosure of at least one of its forms. However, such detailed description is not intended in any way to limit the broad features or principles of the invention, or the scope of patent monopoly to be granted. | The present invention relates to an improved universal multiple angle work piece holder which is capable of setting an object at any desired compound angle so that the object may be machined at any desired location. The invention further relates to an apparatus which can be securely adjusted in a manner that provides a firm support for the object to be machined and provides an angle adjustment design which allows the object to be machined to be adjacent the center lines of the universal multiple angle work piece holder. The present invention also relates to a tool which can easily be converted into other useful tools such as an indexing head to set a work piece at standard angles, a collet holder for use with machines such as a vertical milling machine or a surface grinder, or a dresser for use with a grinding wheel. | 1 |
TECHNICAL FIELD
This invention relates to the production of tiles from synthetic plastics material, for example, floor tiles.
DISCUSSION OF PRIOR ART
Some plastics floor tiles are at present manufactured by using slugs, that is pieces of plastics material, which are bonded to a plastics back ply leaving gaps between the slugs through which the back ply is visible. In this way a tile can be manufactured which carries a pattern created by the arrangement of the slugs and the area of each slug in this pattern is clearly shown by the gap surrounding it and separating it from other slugs and in which the material of the back ply is visible. Such a manufacturing procedure is particularly useful in producing tiles carrying a pattern which simulates wooden parquet flooring.
A disadvantage of tiles produced in this way is that the gaps between slugs, essential to achieve the pattern effect desired, are receptacles for dirt particles and are difficult to clean. This can render such tiles unacceptable or undesirable for use in some situations such as hospitals, food stores or kitchens since the dirt retained can be a reservoir for bacteria. It can also be disfiguring and may render the tile unattractive.
OBJECT OF THE INVENTION
The object of the present invention is to provide a method of manufacturing tiles which can enable a similar patterned appearance to that described above to be achieved but without the disadvantage of leaving gaps between the slugs which can collect dirt but which also enables new pattern effects to be achieved, especially if hygiene requirements are set no higher than with previous tiles.
SUMMARY OF THE INVENTION
According to the invention, a method of making a plastic tile comprises molding a back ply for the tile having raised areas on one surface defining at least one recess for reception of at least one slug, inserting a slug or slugs into the recess or recesses and subjecting the back ply and slug or slugs to a treatment to bond them together.
The invention includes a plastics tile comprising a back ply having raised areas on one surface defining at least one recess, and one or more slugs received in the said recess or recesses and bonded to the back ply.
BRIEF DESCRIPTION OF THE DRAWING
The invention will be further described, by way of example, with reference to the accompanying drawing in which:
FIG. 1 is a plan of part of a tile according to the invention,
FIG. 2 is a plan of part of another tile according to the invention,
FIG. 3 is a cross-section through part of a mold for use in the production of tiles according to the invention,
FIG. 4 is a cross-section through part of a back ply for the tile of FIG. 1, and
FIG. 5 is a cross-section through part of the tile of FIG. 1 taken on the line V--V of FIG. 1.
DESCRIPTION OF PREFERRED EMBODIMENTS
The tile 10 of FIGS. 1 and 5 is a floor tile made of polyvinyl chloride (PVC), a thermoplastic material, and has a pattern which simulates wooden parquet flooring. The tile 10 comprises a back ply 11 of black PVC (FIG. 4) which is formed with raised areas 12 on one surface 13. The raised areas 12 define a number of recesses 14 on the surface 13 and in the embodiment shown comprise series of parallel, narrow ribs, the ribs of adjacent series being arranged at right angles to one another in such a way that each recess 14 has a rectangular shape, each series of recesses 14 comprises four parallel rectangles and each tile 10 has four series of recesses 14. Around the perimeter of each tile 10 are four recesses 14, one along each side of the tile, which are bounded by raised areas 12 only on their inner edges and at each end.
The tile of FIG. 1 is made in a platen press constructed according to known principles and adapted to receive several molds at one time. To make back plies for tiles, each mold is placed on a platen in the press with a sheet of PVC on top of the mold, and the platens originally spaced apart vertically, are pushed together by a ram and are heated. Thus each mold is pressed towards the platen immediately above it by the platen immediately below it and each sheet of PVC is compressed between the associated mold and the platen immediately above it. Each sheet of PVC is thus embossed with the pattern on the mold.
Part of a mold 15 for the back ply of a tile according to the present embodiment of the invention is shown in FIG. 3 and comprises a metal platen 16 formed with grooves 17 for molding the ribs 12.
When the back ply 11 has been molded, it is inserted into another press on a flat mold after slugs 18 of PVC have been inserted, one into each recess 14. Each slug 18 is shaped to fit snugly into a corresponding recess 14 with close tolerance and in the case of the present rectangular recesses 14 and slugs 18, all the rectangular recesses and slugs are the same size and shape.
After insertion in the press, as mentioned, the slugs 18 and back ply 11 are bonded to one another by a treatment comprising applying heat and pressure to them in the press. This softens the thermoplastics material of each and causes them to adhere together. The tile is then complete except that normally sheets of PVC large enough to provide the back plies of a number of individual tiles, and correspondingly large molds and presses, will be used so that after bonding of the slugs to a sheet of PVC constituting a number of back plies, the sheet of PVC will require to be cut to divide it into individual tiles.
The raised areas 12 are advantageously, after bonding of the back ply 11 to the slugs 18, flush with or slightly recessed with respect to the outer surfaces of the slugs (but not so recessed as to provide a channel which will retain any substantial quantity of dirt, which is difficult to clean out). In the embodiment just described, using a black PVC for the back ply 11 and slugs which carry a pattern simulating a wooden surface, the resulting tiles simulate parquet flooring but the spaces between the individual slugs, being filled with the ribs constituted by the raised areas 12, do not harbour significant quantities of dirt in use and the whole surface of the tile being flush and without substantial recesses is easy to clean and can be maintained to standards of hygiene which make it more acceptable for use in some applications for which previous tiles with parquet floor patterning were not acceptable.
Tiles according to the invention are not restricted to parquet floor patterns or to other geometrically regular patterns or to raised areas constituted by narrow ribs such as the raised areas 12 (FIGS. 1, 4 and 5). The invention thus extends to a plastics tile including a plurality of recesses filled by a plurality of slugs producing a patterned effect at the surface of the tile.
FIG. 2, for example shows part of a tile 21 in which raised areas 22 on a back ply of the tile are continuous with one another (as are the ribs constituting the raised areas 12) and define irregularly shaped recesses which receive correspondingly shaped slugs 23 to a close tolerance, so that the surfaces of the slugs 23 are flush, or approximately flush, with the raised areas 22 and there are substantially no gaps between the slugs and the raised areas. By choosing the material of the back ply and raised areas 22 of one color and the slugs 23 of another color, or several different colors, attractive patterns can be achieved.
If desired, more than one slug may be located in a recess on the back ply to further diversify the types of pattern achievable. Of course, if pattern is the primary object and hygienic considerations need not be taken into account any more than with previous tiles, some gaps may be left between slugs and raised or other recesses may be left on the tile surface to achieve particular relief effects.
Materials other than thermoplastics may be used to manufacture tiles according to the invention and the slugs may be bonded to the back ply by separate adhesives. Tiles according to the invention may be used for purposes other than flooring.
The invention is not limited to the specific methods or designs described with reference to the drawings, since modifications of these methods or designs are clearly possible within the spirit and scope of the following claims. | A plastics tile has a back ply having raised areas on one face which define at least one recess and a slug of facing material bonded in the or each recess. The slug or slugs are desirably either flush with or slightly proud of the raised areas of the back ply. | 4 |
TECHNICAL FIELD
[0001] The present invention pertains to a nonwoven fabric and especially to a nonwoven fabric in which a fiber density is gradually distributed in the nonwoven fabric.
BACKGROUND ART
[0002] Patent Literature 1 discloses a nonwoven fabric including first projection portions projecting to the first surface side which is on the side observed in planar view of the sheet-like nonwoven fabric, and second projection portions projecting to the second surface side which is on the opposite side to the first surface, the first projection portions and the second projection portions alternately extending in two directions of the first direction and the second direction in planer view of the nonwoven fabric, and the fiber density in the first surface side at the protruding surface portion of each of the first projection portions being lower than the fiber density in the second surface side thereof.
CITATION LIST
Patent Literature
[0003] PTL 1: Japanese Unexamined Patent Publication No. 2012-144835
SUMMARY OF INVENTION
Technical Problem
[0004] However, in the nonwoven fabric according to the invention disclosed in Patent Literature 1, the fiber density of fibers configuring the nonwoven fabric is not formed so as to be approximately even, when the nonwoven fabric is observed in planar view, and thus the direction in which absorbed liquid permeates the nonwoven fabric cannot be controlled. Accordingly, when such a nonwoven fabric is used for a top sheet of an absorbent article, for example, body fluids such as urine or menstrual blood excreted on the nonwoven fabric may permeate the nonwoven fabric from the position at which the body fluid is excreted to the surroundings by extending without directivity. As a result, the body fluids may permeate outward of the absorbent article, and thus the body fluids may reach the outside of the absorbent article, which causes leakage.
[0005] The object of the present invention is therefore to provide a nonwoven fabric that allows absorbed liquid to permeate therethrough in a desired direction.
Solution to Problem
[0006] To solve the above described problem, the present invention provides a nonwoven fabric comprising a base portion which extends in a planar shape and a plurality of protruding portions which protrude in a thickness direction from the base portion, wherein
[0007] each of the protruding portions has a protruding surface portion, and
[0008] the each protruding surface portion is configured so that a fiber density of the each protruding surface portion is gradually distributed in a predetermined direction in a planar direction of the nonwoven fabric.
Advantageous Effects of Invention
[0009] According to the nonwoven fabric of the present invention, the fiber density of the each protruding surface portion of the protruding portions is gradually distributed in a predetermined direction, whereby the absorbed liquid can permeate the nonwoven fabric in a desired direction.
BRIEF DESCRIPTION OF DRAWING
[0010] FIG. 1 is a planar view of a nonwoven fabric according to a first embodiment of the present invention.
[0011] FIG. 2 is a partial end surface view along a cross-section II-II of FIG. 1 .
[0012] FIG. 3 is an explanatory diagram of a distribution of a fiber density of a protruding surface portion of a protruding portion in a nonwoven fabric 1 shown in FIG. 1 .
[0013] FIG. 4 is a photo which is photographed in a planar view of the nonwoven fabric shown in FIG. 1 .
[0014] FIG. 5 is a photo of a cross-section in which portion V of FIG. 2 is enlarged.
[0015] FIG. 6 is an explanatory diagram of a distribution of a fiber density of a protruding surface portion of a protruding portion in a nonwoven fabric according to a second embodiment.
[0016] FIG. 7 is an explanatory diagram of distributions of a fiber density of a protruding surface portion of a protruding portion, and a fiber density of a base portion positioned in a state of surrounding the protruding portion, in a nonwoven fabric according to a third embodiment.
[0017] FIG. 8 is an explanatory diagram of distributions of a fiber density of a protruding surface portion of a protruding portion, and a fiber density of a base portion positioned in a state of surrounding the protruding portion, in a nonwoven fabric according to a fourth embodiment.
[0018] FIG. 9 is a schematic view showing a general outline of manufacturing equipment to manufacture the nonwoven fabric according to the embodiment of the present invention.
[0019] FIG. 10 is an enlarged view of portion X in FIG. 9 .
[0020] FIG. 11 is an explanatory diagram of measurement points to measure a fiber density of a protruding surface portion of a protruding portion of the nonwoven fabric according to the first to the third examples.
DESCRIPTION OF EMBODIMENTS
First Embodiment
[0021] Hereinbelow, a nonwoven fabric 1 according to a first embodiment of the present invention is described with reference to FIG. 1 to FIG. 5 .
[0022] FIG. 1 is a planar view of a nonwoven fabric according to the first embodiment, and FIG. 2 is a partial end surface view along a cross-section II-II of FIG. 1 . The nonwoven fabric 1 according to the first embodiment extends in a plane of the nonwoven fabric 1 defined by a longitudinal direction Lo and a transverse direction Tr, and has the first surface FF which can be observed in a planar view of FIG. 1 and a second surface FS which is positioned at the opposite side of the first surface FF.
[0023] As shown in FIG. 1 and FIG. 2 , the nonwoven fabric 1 is formed by a base portion 10 which extends in an approximately planar shape, and a plurality of protruding portions 12 which protrude from the base portion 10 in a thickness direction Th, and to the side of the first surface FF in the first embodiment. Each of the protruding portions 12 includes a protruding surface portion 12 T which is distant from the base portion 10 in the thickness direction Th of the nonwoven fabric 1 . Here, the protruding surface portion 12 T is referred to as a portion of the protruding portion 12 positioned on a side where an apex portion of the protruding portion 12 is present, the apex portion being most distant from the base portion 10 in the thickness direction Th, with respect to the middle point in the thickness direction Th between the base portion 10 and the apex portion of the protruding portion 12 , and the portion further forming a certain surface facing the protruding direction of the protruding portion 12 from the base portion 10 .
[0024] In the first embodiment, each of the protruding surface portions 12 T is approximately flat. However, each of the protruding surface portions 12 T need not be made into a completely flat surface, and may include a certain inclined surface or a curved surface.
[0025] Further, in the first embodiment, each of the protruding portions 12 has an approximately cylinder-like shape with a diameter of approximately 10 mm in appearance. In another embodiment, each of the protruding portions 12 may take the shape of, for example a truncated cone, an elliptic or a polygonal cylinder, or an elliptic or a polygonal truncated cone, etc., each having a protruding surface portion with a certain area.
[0026] FIG. 3 is an explanatory diagram of a distribution of a fiber density of the protruding surface portion 12 T of the protruding portion 12 in the nonwoven fabric 1 shown in FIG. 1 . Incidentally, FIG. 3 gives an explanation by focusing on one protruding portion 12 , and describes the distribution of the fiber density of the protruding surface portion 12 T, by the amount of the density of (the number of) the sign “X”.
[0027] As shown in FIG. 3 , each of the protruding surface portions 12 T is configured so that the fiber density of each of the protruding surface portions 12 T is gradually distributed in a longitudinal direction Lo of the nonwoven fabric 1 , among the planar direction of the nonwoven fabric 1 . That is to say, the protruding surface portion 12 T has, on a certain segment extending in the longitudinal direction Lo, portions in which the fiber density on one side of the longitudinal direction Lo is higher, and the fiber density on the other side of the longitudinal direction Lo is lower.
[0028] Further, in other words, in the nonwoven fabric 1 according to the first embodiment, when each of the protruding surface portions 12 T is divided into two hemi-protruding surface portions 121 T, 122 T, each having the same areas, by a virtual line VL which extends in a direction perpendicular to the longitudinal direction Lo of the nonwoven fabric 1 in a planar view of the nonwoven fabric 1 , that is to say, in a transverse direction Tr, the fiber density of one hemi-protruding surface portion 121 T is higher than the fiber density of the other hemi-protruding surface portion 122 T. Here, “the fiber density of a hemi-protruding surface portion” is generally referred to as an average of the fiber densities in the entire hemi-protruding surface portions 121 T and 122 T, however, when measuring the fiber densities as described later, it is referred to as an average of the fiber densities obtained by cutting each of the hemi-protruding surface portions 121 T and 122 T in a direction vertical to the direction in which the fibers are gradually distributed, that is to say, in the transverse direction Tr in the case of the first embodiment, then dividing each of the hemi-protruding surface portions 121 T and 122 T into three parts in a direction in which the fibers are gradually distributed, that is to say, in the longitudinal direction Lo of the nonwoven fabric 1 in the case of the first embodiment, and thus the fiber densities are measured in the center portions in the transverse direction Tr at these cutting planes.
[0029] FIG. 4 is a photo which is obtained by photographing the nonwoven fabric shown in FIG. 1 in a planar view of the nonwoven fabric, on a black stand. In the photo shown in FIG. 4 , the shades of colors show how high or low the fiber densities are. That is to say, the darker the black is in the photo shown in FIG. 4 , the color of the photographing stand can be easily observed therethrough, and thus indicating that the fiber density is low, whereas the darker the white is, the color of the photographing stand can be less easily observed therethrough, and thus indicating that the fiber density is high. The photo of FIG. 4 also supports that at a planar view of the nonwoven fabric 1 in the nonwoven fabric 1 according to the first embodiment, the fiber density of the protruding surface portion 12 T of the protruding portion 12 is gradually distributed in the longitudinal direction Lo among the planar direction of the nonwoven fabric 1 . This is because, when the protruding surface portion 12 T in FIG. 4 is observed, it shows a tendency that one side in the longitudinal direction Lo is darker in black, and the other side in the longitudinal direction Lo is darker in white.
[0030] In the present invention, when measuring “the fiber density”, an index of the number of portions FC at which fibers are cut per 1 mm 2 , in the cutting plane of the nonwoven fabric 1 is used. To be more specific, a cutting plane of a certain area (for example, approximately 2.0 mm 2 ) is observed by using an electron scanning microscope (for example, “Real Surface View Microscope VE-7800” manufactured by Keyence Corporation), with the magnification being adjusted to approximately 50 to 100 times, and the number of portions FC at which the fibers are cut (as shown in FIG. 5 ) is counted. The cutting plane to be observed includes the entirety throughout the thickness direction Th from the first surface FF to the second surface FS. Then, the number of cut portions is converted to the number of portions per 1 mm 2 , and thus the converted number is obtained as the index of “the fiber density”.
[0031] The fibers used for the nonwoven fabric 1 in the first embodiment are fibers having a sheath-core structure, in which the material of the sheath is high density polyethylene (HDPE), and the material of the core is polyethylene terephthalate (PET).
[0032] The fibers to be used in the nonwoven fabric may be natural fibers, regenerated fibers (rayon, acetate, etc.), thermoplastic resin fibers (polyolefins such as polyethylene, polypropylene, polybutylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, or ionomer resin; polyesters such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, or polylactic acid; polyamides such as nylon, etc.) or their surface modified fibers. Among these fibers, the thermoplastic resin fibers or their surface modified fibers are preferable. Further, these fibers may be composite fibers such as sheath-core type fibers, side-by-side type fibers, island-sea type fibers; hollow type fibers; atypical fibers such as flat, Y-type or C-type fibers; solid crimp fibers such as latent crimped or actual crimped fibers; split fibers split by physical load by water flow, heat or embossing; etc. Incidentally, these fibers may be hydrophilic fibers, or may be hydrophobic fibers. However, when using hydrophobic fibers, an application of hydrophilic oil solution to the fibers, etc., are additionally required.
[0033] Further, as shown in FIG. 1 , in the nonwoven fabric 1 according to the first embodiment, the protruding portions 12 are aligned along a first direction D 1 and along a second direction D 2 , respectively in a linear manner. Here, the first direction D 1 is the same as the transverse direction Tr, and the second direction D 2 is tilted from the first direction D 1 by 60°. Further, in the nonwoven fabric 1 according to the first embodiment, by disposing the protruding portions 12 with an equal interval, the base portions 10 and the protruding portions 12 are disposed evenly. Accordingly, when the nonwoven fabric 1 is used as a top sheet of an absorbent article such as a disposable diaper, a sanitary napkin, or the like, for example, with the first surface FF placed as an exterior surface thereof, the base portions 10 which allow the body fluids excreted on the nonwoven fabric 1 to permeate inside where an absorbent body and the like of the absorbent article are positioned, and the protruding portions 12 which allow the body fluids to permeate therethrough in a desired direction, can be disposed with a preferable distribution.
[0034] Further, as shown in FIG. 1 , in the nonwoven fabric 1 according to the first embodiment, the protruding portions 12 which are adjacent to each other in the first direction D 1 and in the second direction D 2 are respectively provided intermittently with the base portion 10 placed in between. As a result, the body fluids excreted on the first surface FF permeates therethrough toward a direction in which the fiber density is gradually distributed, whereby the body fluids can be moved from the protruding surface portion 12 T of the protruding portion 12 to the adjacent base portion 10 . Accordingly, for example, when the nonwoven fabric 1 is used as a top sheet of an absorbent article, liquids can effectively permeate inside the absorbent article from the base portions 10 .
[0035] Hereinbelow, functions of the nonwoven fabric according to the first embodiment are described. In the nonwoven fabric 1 according to the first embodiment, as described above, each of the protruding surface portions 12 T are configured so that the fiber density of the protruding surface portions 12 T is gradually distributed in the longitudinal direction Lo among the planar direction of the nonwoven fabric 1 . Accordingly, the liquids absorbed by the fibers configuring the protruding portions 12 can easily permeate therethrough from a side where the fiber density is lower to a side where the fiber density is higher by the capillary phenomenon, and thus the liquids can be easily moved to the side where the fiber density is higher in the longitudinal direction Lo. Accordingly, by providing the nonwoven fabric so that the side with higher fiber density is disposed in the direction in which liquids preferably permeate therethrough, the absorbed liquids can permeate therethrough in a desired direction. Incidentally, in the present specification, it should be noted that “liquids can permeate therethrough in a desired direction” is referred not to as the liquids permeating therethrough only in the desired direction, but is referred to as the liquids permeating therethrough in the desired direction being increased.
[0036] Incidentally, the fiber density of the protruding surface portions 12 T is gradually distributed in the longitudinal direction Lo in the nonwoven fabric 1 according to the first embodiment, however, the fiber density of the protruding surface portions 12 T may alternately be gradually distributed in any direction among the planar direction of the nonwoven fabric 1 . That is to say, the protruding surface portions 12 T may be configured so that the fiber density of the protruding surface portions 12 T is gradually distributed in a predetermined direction among the planar direction of the nonwoven fabric 1 . Further, the side at which the fiber density is higher is disposed toward the direction to which liquids preferably permeate, whereby the liquids can permeate therethrough in the desired direction.
[0037] Further, in FIG. 3 , the fiber distribution in the protruding surface portion 12 T of one protruding portion 12 has been described, however, in the nonwoven fabric 1 according to the first embodiment, each of the protruding surface portions 12 T of each of the protruding portions 12 has the fiber distribution which is similar to that shown in FIG. 3 . However, the fiber densities of the protruding surface portions 12 T of the entire protruding portions 12 are not necessarily gradually distributed, and the nonwoven fabric 1 in which a fiber density of the protruding surface portion 12 T of the protruding portion 12 for at least a part of the protruding portions 12 is gradually distributed can be regarded as a nonwoven fabric which is within the scope of the present invention. This is because, such nonwoven fabric can still cause advantageous effects of the nonwoven fabric 1 according to the present invention, which is to allow the liquids absorbed by the nonwoven fabric 1 to permeate therethrough in the desired direction.
[0038] Further, the degree of the uneven distribution of the fiber density in the protruding surface portion 12 T may be as uneven as the one that allows the liquids absorbed by the nonwoven fabric 1 to permeate therethrough in the desired direction.
[0039] In the nonwoven fabric 1 according to the first embodiment, as described above, the protruding portions 12 are aligned along the first direction D 1 and along the second direction D 2 which is tilted from the first direction D 1 by 60°, respectively in a linear manner. In another embodiment, the second direction D 2 is tilted from the first direction D 1 by an angle other than 60°. In still another embodiment, the protruding portions 12 are aligned along only one direction in a linear manner. In still another embodiment, the protruding portions 12 are not aligned along a particular direction, and are disposed at arbitrary positions.
[0040] Further, in the nonwoven fabric 1 according to the first embodiment, as described above, by disposing the protruding portions 12 with an equal interval, the base portions 10 and the protruding portions 12 are disposed evenly. In another embodiment, the intervals of the protruding portions 12 are not even.
[0041] In another embodiment, the protruding portions 12 are aligned along either one of the first direction D 1 and the second direction D 2 in a linear manner, and in still another embodiment, the protruding portions 12 are not aligned along a particular direction, and are disposed randomly.
Second Embodiment
[0042] Hereinbelow, a nonwoven fabric 1 according to a second embodiment of the present invention is described with reference to FIG. 6 . As for the second embodiment, aspects that are different from those in the first embodiment are mainly described.
[0043] FIG. 6 is an explanatory diagram of the distribution of the fiber density of the protruding surface portion 12 T of the protruding portion 12 in the nonwoven fabric 1 according to the second embodiment. As shown in FIG. 6 , in each of the protruding portions 12 , the edge portion 12 TE of the protruding surface portion 12 T has a higher fiber density than the center portion 12 TC of the protruding surface portion 12 T. By configuring the fiber density of the edge portion 12 TE of the protruding surface portion 12 T to be high, the rigidity of the edge portion 12 TE increases, whereby when an external force is added to the protruding portions 12 , the protruding portions 12 can maintain the shapes thereof. Accordingly, for example, when the nonwoven fabric 1 is packaged to be sold, the shape of the nonwoven fabric 1 can be suppressed from being collapsed, when being added with an external force to the protruding portions 12 . As a result, such nonwoven fabric is preferable in that the nonwoven fabric 1 can cause functions and advantageous effects of the superiority in reforming or keeping the shapes thereof even after the nonwoven fabric 1 is packaged and thereafter is opened from the package. Further, the nonwoven fabric 1 according to the second embodiment is also preferable in the appearance thereof, since the nonwoven fabric 1 can keep the shapes of the protruding portions 12 at the time of manufacturing even after the nonwoven fabric 1 is packaged and is opened.
[0044] Incidentally, the edge portion 12 TE is in the region of the protruding surface portion 12 T, which is along the edge 12 TEE of the protruding surface portion 12 T and has a certain width in the direction toward the center portion 12 TC, as wide as to confirm the fiber density of the edge portion 12 TE. Further, the center portion 12 TC is a portion which is more distant from the edge 12 TEE than the edge portion 12 TE. Incidentally, when the identification of the edge portion 12 TE and the center portion 12 TC is difficult, a certain range around the center of gravity of the geometric shape of the protruding surface portion 12 T in a planar view of the nonwoven fabric 1 is set as the center portion 12 TC. Further, in the case of the second embodiment, the width of the edge portion 12 TE is approximately 1 mm with respect to the protruding surface portion 12 T having the diameter of approximately 10 mm, that is, the length of approximately 10% of the diameter (or the stretching length of the protruding surface portion 12 T).
[0045] Incidentally, also in the second embodiment, in the same manner as the nonwoven fabric 1 according to the first embodiment, each of the protruding surface portions 12 T is configured so that the fiber density of each of the protruding surface portions 12 T is gradually distributed in a longitudinal direction Lo of the nonwoven fabric 1 , among the planar direction of the nonwoven fabric 1 . That is to say, in the second embodiment, on a certain segment extending in the longitudinal direction Lo at the center portion 12 TC of the protruding surface portion 12 T, portions in which the fiber density on one side of the longitudinal direction Lo is higher, and the fiber density on the other side of the longitudinal direction Lo is lower are present.
Third Embodiment
[0046] Hereinbelow, a nonwoven fabric 1 according to a third embodiment of the present invention is described with reference to FIG. 7 . As for the third embodiment, aspects that are different from those in the first embodiment are mainly described.
[0047] FIG. 7 is an explanatory diagram of distributions of the fiber density of the protruding surface portion 12 T of the protruding portion 12 , and the fiber density of the base portion 10 positioned in a state of surrounding the protruding portion 12 , in the nonwoven fabric 1 according to the third embodiment. Referring to FIG. 7 , in the third embodiment, in the planar view of the nonwoven fabric 1 , in the portion 10 L of the base portion 10 which is positioned close to the portion 12 TH at which the fiber density of the fibers configuring the protruding surface portion 12 T of the protruding portion 12 is high, the fiber density is lower than the other portions in the base portion 10 . That is to say, the fiber density of the base portion 10 surrounding the protruding portion 12 decreases as the portion 12 TH at which the fiber density of the protruding portion 12 is high is located closer therefrom.
[0048] As a result, a portion in which the fiber density is lower than the other portions is formed in the base portion 10 . Accordingly, for example, when the nonwoven fabric 1 according to the third embodiment is used as a top sheet of an absorbent article, the liquids which have moved to the portion 12 TH at which the fiber density of the protruding portion 12 is high can be allowed to permeate therethrough quickly at the portion 10 L at which the fiber density of the base portion 10 is low which is positioned nearby, as described above. As a result, it is preferable because the liquids excreted on the nonwoven fabric 1 can be allowed to permeate inside of the absorbent article in which the absorbent body and the like are provided.
Fourth Embodiment
[0049] Hereinbelow, a nonwoven fabric 1 according to a fourth embodiment of the present invention is described with reference to FIG. 8 . As for the fourth embodiment, aspects that are different from those in the third embodiment are mainly described.
[0050] FIG. 8 is an explanatory diagram of distributions of the fiber density of the protruding surface portion 12 T of the protruding portion 12 , and the fiber density of the base portion 10 positioned in a state of surrounding the protruding portion 12 , in the nonwoven fabric 1 according to the fourth embodiment. In the nonwoven fabric according to the fourth embodiment, in the same manner as the nonwoven fabric according to the second embodiment, in each of the protruding portions 12 , the edge portion 12 TE of the protruding surface portion 12 T has a higher fiber density than the center portion 12 TC of the protruding surface portion 12 T. That is to say, the nonwoven fabric 1 according to the fourth embodiment is a nonwoven fabric having the functions and advantageous effects of both the nonwoven fabrics 1 according to the second and the third embodiments. These effects are the same as the functions and the advantageous effects of the nonwoven fabrics 1 according to the second and the third embodiments, and thus the description thereof is omitted.
(Manufacturing Method of a Nonwoven Fabric)
[0051] Hereinbelow, the manufacturing method of the nonwoven fabric 1 according to the fourth embodiment is described. FIG. 9 is a schematic view showing the general outline of the manufacturing equipment 3 to manufacture the nonwoven fabric 1 according to the embodiment of the present invention. and FIG. 10 is an enlarged view of portion X in FIG. 9 . The manufacturing equipment 3 is provided with a carding machine 20 which opens and adjusts the basis weight of the fibers F 1 , a suction drum 22 and an air jet nozzle 26 which form the fibers F 2 so as to be the shape of the nonwoven fabric 1 , and a heat processing machine 28 which performs heat processing for the fiber F 3 so that the shape formed into the fibers F 3 is fixed. Incidentally, in FIG. 9 , the later described fibers F 1 to F 3 and the nonwoven fabric 1 are conveyed in the direction shown in the arrow MD, and the conveying direction MD matches with the longitudinal direction Lo of the nonwoven fabric 1 .
[0052] The manufacturing method of the nonwoven fabric 1 is briefly described as follows. First, the fibers F 1 is opened and the basis weight thereof is adjusted by the carding machine 20 , and then the opened fibers F 2 are supplied to the suction drum 22 . Next, the fibers F 2 are sucked onto the exterior surface of the suction drum 22 at which a pattern plate 24 is provided, and are blown with warm air by the air jet nozzle 26 while being moved, and thus the fibers F 2 are formed so as to be the shape of the nonwoven fabric 1 according to the above described embodiment. Next, the formed fibers F 3 are subjected to heat processing in the heat processing machine 28 , and the shape of the fibers F 3 which have been formed in the previous step is fixed, whereby the nonwoven fabric 1 is completed.
[0053] Hereinbelow, the manufacturing method of the nonwoven fabric 1 is described in detail. In the manufacturing steps of the nonwoven fabric 1 , the opened fibers F 1 are first supplied to the carding machine 20 . In the carding machine 20 , the fibers F 1 are further opened, and the basis weight (mass per unit area) of the fibers F 1 is adjusted to a desirable value.
[0054] The fibers F 2 having passed through the carding machine 20 are then supplied to the suction drum 22 . The interior of the suction drum 22 is formed to be hollow, and the interior of the suction drum 22 has negative pressure, due to the air being sucked by suction means such as a blower, etc. A plurality of suction holes 22 t are provided on the exterior surface of the suction drum 22 , whereby the outside air can be sucked. Incidentally, the size of the suction holes of the suction drum 22 is very small, and thus the fibers F 2 are not sucked into the interior of the suction drum 22 .
[0055] The exterior surface of the suction drum 22 is covered by the pattern plate 24 in the entire circumference thereof, and to be more specific, the fibers F 2 are supplied onto the pattern plate 24 . In the present manufacturing method, the pattern plate 24 is a perforated plate in which through holes 24 t each having a complementary shape to each of the protruding portions 12 of the nonwoven fabric 1 are provided with the distribution of the protruding portions 12 .
[0056] According to such configuration, the suction holes of the suction drum 22 exposed at the through holes 24 t of the pattern plate 24 suck the fibers F 2 supplied onto the pattern plate 24 . Incidentally, in the nonwoven fabric 1 according to the present embodiment, the positional difference of the height of the first surface FF in the thickness direction Th of the nonwoven fabric 1 between the base portion 10 and the protruding surface portion 12 T of each of the protruding portions 12 is approximately equal to the thickness of the pattern plate 24 .
[0057] Incidentally, in the present manufacturing method, the suction drum 22 is configured so that on the exterior surface thereof, the suction is performed for the fibers F 2 within the area AS from the point SS at which the fibers F 2 are passed from the upstream belt conveyor UB to the point SE at which the fibers F 2 are passed on to the downstream belt conveyor DB, and the suction is not performed in the other areas AN. Such configuration is adopted so as to improve the efficiency of the suction function by the suction drum 22 .
[0058] The fibers F 2 sucked onto the exterior surface of the suction drum 22 are blown with warm air by the air jet nozzle 26 . Here, the air jet nozzle 26 has a mechanism which uniformly jets a predetermined amount of the warm air in a uniform width in the width direction. By adjusting the width of the blowing ports, the distance between the blowing ports and the fibers F 2 , etc., the air jet nozzle 26 is configured so that the warm air is substantially uniformly jetted over the entire width of the laminate formed by the fibers F 2 . The fibers F 2 can be formed so as to be the shape of the nonwoven fabric 1 according to the present embodiment, by the suction function and the jetting function by the suction drum 22 and the air jet nozzle 26 .
[0059] The temperature of the warm air jetted from the air jet nozzle 26 is higher than the melting point of the fibers F 2 , however, the temperature of the warm air is adjusted not to be too high, in order to prevent the nonwoven fabric 1 from being too stiff after the nonwoven fabric 1 is completed. Further, the velocity of the warm air is determined so as to form the fibers F 2 into a desired shape. Generally, the temperature and the velocity of the warm air jetted from the air jet nozzle 26 differ according to the material of the fibers to be used, the basis weight, the shape of the nonwoven fabric 1 after completion, etc. However, the optimal temperature and velocity are preferably determined for example by experiments, etc. For example, the temperature of the warm air jetted from the air jet nozzle 26 ranges preferably from 80 [° C.] to 400 [° C.], and the velocity thereof ranges preferably from 10 to 200 [m/sec]. In the present manufacturing method, the temperature of the warm air jetted from the air jet nozzle 26 is 180 [° C.], and the velocity thereof is 38.9 [m/sec]. Incidentally, at this stage, the fibers F 2 can be formed, and at the same time, the shape thereof can be fixed to a certain degree, by jetting the warm air to the fibers F 2 with a temperature higher than the melting point thereof.
[0060] Incidentally, in the manufacturing equipment 3 according to the present embodiment, the surface of the laminate formed by the fibers F 2 facing the suction drum 22 and the pattern plate 24 is to be the first surface FF of the nonwoven fabric 1 , and the surface of the laminate facing the air jet nozzle 26 is to be the second surface FS of the nonwoven fabric 1 .
[0061] When the fibers F 2 are jetted by the air jet nozzle 26 , the fibers F 2 are blown and are moved to the surroundings. As a result, the amount of fibers at the jetted portion is decreased, and whereby the fiber density at the jetted portion is decreased. On the other hand, since the air jet nozzle 26 is disposed in a fixed state, the fibers F 2 located inside the through holes 24 t of the pattern plate 24 are eventually jetted with warm air at the portion F 2 tu which is positioned in the upstream side of the conveying direction MD, whereby the fiber density thereof is lowered. Subsequently, the fibers F 2 moved by the jetting function of the air jet nozzle 26 are fixed to the position after movement by the suction function of the suction drum 22 . To be more specific, first, warm air is jetted to the portion F 2 td at the downstream side of the conveying direction MD of the fibers F 2 located inside the through holes 24 t, and the fibers located at the portion F 2 td are blown and are moved to the downstream side of the conveying direction MD. However, subsequently, warm air is jetted to the portion F 2 tu at the upstream side of the conveying direction MD of the fibers F 2 located inside the through holes 24 t, and the fibers are moved to the downstream side of the conveying direction MD. Then, the fibers F 2 located inside the through holes 24 t of the pattern plate 24 are continuously sucked by the suction drum 22 , whereby the fibers F 2 are conveyed to the subsequent processing with the movement of the fibers being suppressed. As a result, eventually, the fiber density of the portion F 2 td at the downstream side of the conveying direction MD of the fibers F 2 is made higher, and oppositely, the fiber density of the portion F 2 tu at the upstream side of the conveying direction MD of the fibers F 2 which are jetted at the final stage is made lower. Accordingly, in the nonwoven fabric 1 , in each of the protruding portions 12 , the protruding surface portion 12 T is configured so that the fiber density of the protruding surface portion 12 T is gradually distributed in a predetermined direction, which is the longitudinal direction Lo of the nonwoven fabric 1 matching with the conveying direction MD in the above described embodiment.
[0062] Further, the same can be said for the portion F 2 su which is positioned at the upstream side of the conveying direction MD, among the fibers F 2 located on the exterior surface 24 s which is positioned in between the through holes 24 t of the pattern plate 24 . That is to say, warm air is jetted to the portion F 2 su, whereby the fibers F 2 are blown and are moved to the surroundings. At this time, the fibers F 2 also move inside the through holes 24 t. Subsequently, warm air is jetted to the portion F 2 tu at the upstream side of the conveying direction of the fibers F 2 located inside the through holes 24 t, among the fibers F 2 , however, once the fibers F 2 are moved inside the through holes 24 t, the fibers F 2 do not come back to the exterior surface 24 s from inside the through holes 24 t, whereby the fiber density at the portion F 2 su is lowered. On the other hand, the fiber density at the portion F 2 tu at the upstream side of the conveying direction of the fibers F 2 inside the through holes 24 t is made higher. As a result, as in the nonwoven fabric 1 according to the third embodiment, the fiber density of the base portion 10 surrounding the protruding portion 12 decreases as the portion 12 TH at which the fiber density of the protruding portion 12 is high is located closer therefrom.
[0063] Further, it is difficult for a corner portion Co which is formed at the portion where the side walls 24 w forming the through holes 24 t of the pattern plate 24 and the exterior surface of the suction drum 22 are connected to each other to receive warm air, and it is difficult for the fibers to move from the corner portion Co. On the other hand, the fibers are blown from the surroundings of the corner portion Co by the warm air jetted from the air jet nozzle 26 and are moved to the corner portion Co. Then, the corner portion Co corresponds to the edge portion 12 TE of the protruding portion 12 in the nonwoven fabric 1 . As described above, in the above manufacturing method, the amount of the fibers at the corner portion Co is increased, and as a result, as in the nonwoven fabric 1 according to the second embodiment, the edge portion 12 TE of the protruding portion 12 has a higher fiber density than the center portion 12 TC of the protruding portion.
[0064] The shape of the protruding portion 12 is eventually determined by the shape of the through holes 24 t of the pattern plate 24 , the temperature and the velocity of the warm air jetted from the air jet nozzle 26 , and the like.
[0065] As shown in FIG. 9 , the fibers F 3 formed by the above described suction and jetting functions are then transferred to the heat processing machine 28 . Fibers F 3 are subjected to heat processing in the heat processing machine 28 , and the shape formed in the prior stages is fixed. In the heat processing machine 28 , by performing the heat processing for the fibers F 3 at a relatively low temperature with respect to the melting point of the fibers and with the warm air of low velocity for long hours, the shape of the fibers F 3 formed at the prior stages are fixed, and can also provide flexibility to the nonwoven fabric 1 . Generally, the temperature and the velocity of the warm air in the heat processing machine 28 , the processing time, etc., differ according to the material of the fibers to be used, the basis weight, etc. However, the optimal temperature and velocity are preferably determined for example by experiments, etc.
[0066] When the heat processing of the fibers F 3 by the heat processing machine 28 is terminated, the nonwoven fabric 1 is completed. The completed nonwoven fabric 1 is cut to a desired size, and is used.
[0067] The manufacturing method of the nonwoven fabric 1 according to the fourth embodiment has been described, however, by suitably changing shape of the pattern plate 24 , the temperature and the velocity of the warm air jetted from the air jet nozzle 26 , etc., the nonwoven fabrics 1 according to the first to the third embodiment can also be manufactured.
EXAMPLES
[0068] In the present examples, a liquid diffusion length test was performed with respect to the nonwoven fabrics set with various conditions. The liquid diffusion length test is a test to confirm that the liquid absorbed by a nonwoven fabric permeates therethrough with directivity.
[0069] Hereinbelow, the Examples 1 to 3 and the Comparative Example are described.
Examples 1 to 3
[0070] The nonwoven fabrics according to Examples 1 to 3 are the nonwoven fabrics manufactured by the above described manufacturing method. The temperature and the velocity of the warm air jetted from the air jet nozzle 26 when manufacturing these nonwoven fabrics, and the temperature and the velocity of the heat processing performed inside the heat processing machine 28 are shown in the later described Table 1. Further, the uneven distribution of the fiber density of the protruding surface portion in the protruding portion was measured according to the above described measuring method of the fiber density in the surroundings of the two measurement points PH, PL shown in FIG. 11 . One measurement point PH is the midpoint between the center point C of the protruding surface portion 12 T in the planar view of the nonwoven fabric 1 and the edge 12 TEE positioned at the side where the fiber density is higher along the longitudinal direction Lo form the center point C. Further, the other measurement point PL is the midpoint between the center point C of the protruding surface portion 12 T and the edge 12 TEE positioned at the side where the fiber density is lower along the longitudinal direction Lo form the center point C. When the difference of the fiber densities measured at these measurement points are large, the fiber density of the protruding surface portion can be evaluated as being more gradually distributed. Referring to the later described Table 1, the fiber density of the protruding surface portion of the nonwoven fabric according to the second embodiment is more gradually distributed than that according to the first embodiment. Further, the fiber density of the protruding surface portion of the nonwoven fabric according to the third embodiment is more gradually distributed than that according to the second embodiment.
Comparative Example
[0071] The nonwoven fabric according to the Comparative Example was formed in which the fibers opened by the carding machine were not sucked by the suction drum, were not jetted with warm air by the air jet nozzle, and were formed into a planar shape so that the fiber density was even by the heat processing machine. The temperature and the velocity of the heat processing performed inside the heat processing machine at this time are shown in the later described Table 1.
[0072] Next, the testing method of the test performed in the present Examples is described. The liquid diffusion length test was performed by disposing the samples of the nonwoven fabrics according to the Examples and the Comparative Example which were cut into the width of 150 mm and the length of 300 mm, on a stainless plate having a width of 250 mm and a length of 450 mm, and by dropping 20 cc of simulated artificial urine onto one protruding portion by 2.5 seconds. At this time, the lengthwise direction of the samples was the direction in which the fiber density of the fibers configuring the protruding surface portion of the protruding portion was gradually distributed, and the direction in which the fiber density of the protruding surface portion was higher along the lengthwise direction was set as DH direction, and the direction in which the fiber density of the protruding surface portion was lower was set as the DL direction. Further, the lengths dh and dl from the dropping point of the artificial urine at which the artificial urine permeated therethrough and reached in the DH direction and in the DL direction were respectively measured. The amount obtained by subtracting the length dl from the length dh was regarded as the liquid diffusion length. The above described liquid diffusion length test was performed for three times, and the amount obtained as the average of each of the measurement values was calculated as the liquid diffusion length.
[0073] Incidentally, the artificial urine used in the liquid diffusion length test was prepared by dissolving 200 g of urea, 80 g of sodium chloride, 8 g of magnesium sulfate, 3 g of calcium chloride and approximately 1 g of a pigment (Blue No. 1) in 10 L of an ion exchanged water.
[0074] Table 1 is shown below. In Table 1, the basis weight, the thickness, the manufacturing conditions of the nonwoven fabrics according to the Examples 1 to 3 and the Comparative Example, the fiber density in the protruding surface portion at the surroundings of each of the measurement points PH, PL, and the results of the liquid diffusion length test are shown. Incidentally, the “thickness” shown in Table 1 is the average value of the thicknesses measured three times under the pressure of 3 gf/cm 2 , and in the nonwoven fabrics according to the Examples 1 to 3, the thickness of the protruding portion was measured.
[0000]
TABLE 1
Example 1
Example 2
Example 3
Comparative Example
Basis Weight
(g/m2)
25
25
25
30
Thickness
(mm)
1.9
1.3
1.2
2.3
Air Jet
Temperature
(° C.)
180
180
170
—
Warm Air
Velocity
(m/sec)
38.9
44.4
50.0
—
Heat Processing Machine
Temperature
(° C.)
135
135
135
133
Warm Air
Velocity
(m/sec)
0.9
0.9
0.9
0.9
Fiber Density (PH)
(numbers)
44
40
48
—
Fiber Density (PL)
(numbers)
36
25
28
—
Liquid Diffusion Length
(mm)
11
23
31
−1
[0075] As shown in the results of the liquid diffusion length test of Table 1, the more gradually distributed the fiber density of the protruding surface portion is, the longer the liquid diffusion length is. Accordingly, the more gradually distributed the fiber density is, the liquid absorbed in the nonwoven fabric can be permeated therethrough in the direction toward which the fiber density of the fibers configuring the protruded surface portion is gradually distributed.
[0076] All the features which can be understood by those skilled in the art from the description of the specification, drawings and the claims can be applied independently or can be applied in optional combination with another one or a plurality of features disclosed herein to be bound together, as long as such features are explicitly excluded or its technical aspect becomes an impossible or a meaningless combination, even when such features are described only in combination with another specific feature in this specification.
[0077] For example, in the nonwoven fabric 1 according to another embodiment, the edge portion 12 TE of the protruding surface portion 12 T has a higher fiber density than the center portion 12 TC of the protruding surface portion 12 T as in the second embodiment, and at the same time, the fiber density of the base portion 10 surrounding the protruding portion 12 decreases as the portion 12 TH at which the fiber density of the protruding portion 12 is high is located closer therefrom, as in the third embodiment.
[0078] The present invention is defined as follows.
[0079] (1) A nonwoven fabric comprising a base portion which extends in a planar shape and a plurality of protruding portions which protrude in a thickness direction from the base portion, wherein
[0080] each of the protruding portions has a protruding surface portion, and
[0081] the each protruding surface portion is configured so that a fiber density of the each protruding surface portion is gradually distributed in a predetermined direction in a planar direction of the nonwoven fabric.
[0082] (2) The nonwoven fabric according to (1), wherein
[0083] in each of the protruding portions, an edge portion of the each protruding surface portion has a higher fiber density than a center portion of the each protruding surface portion.
[0084] (3) The nonwoven fabric according to (1) Or (2), wherein
[0085] a fiber density of the base portion surrounding the protruding portions decreases as a fiber density of the protruding portions increases.
[0086] (4) The nonwoven fabric according to any one of (1) to (3), wherein
[0087] when the each protruding surface portion is divided into two hemi-protruding surface portions by a virtual line which extends in a direction perpendicular to the predetermined direction in a planar view of the nonwoven fabric, the two hemi-protruding surface portions having the same areas, a fiber density of one hemi-protruding surface portion is higher than a fiber density of the other hemi-protruding surface portion.
[0088] (5) The nonwoven fabric according to any one of (1) to (4), wherein
[0089] the protruding portions are aligned along a first direction and along a second direction which is different from the first direction.
[0090] (6) The nonwoven fabric according to (5), wherein
[0091] each of the protruding portions is arranged with equal intervals in the first direction and in the second direction, with the base portion disposed in between.
[0092] (7) The nonwoven fabric according to (5) or (6), wherein
[0093] the predetermined direction matches the first direction or the second direction.
[0094] (8) The nonwoven fabric according to any one of (1) to (7), wherein
[0095] the predetermined direction matches a conveyance direction when manufacturing the nonwoven fabric.
REFERENCE SIGNS LIST
[0000]
1 nonwoven fabric
10 base portion
12 protruding portion
12 T protruding surface portion | The present disclosure relates to a non-woven fabric that is formed from a base part that spreads out in a planar shape and from a plurality of projecting parts that protrude in a thickness direction (Th) from the base part. Each of the projecting parts has a projecting surface part. Each of the projecting surface parts is configured such that the fiber density of the projecting surface part increases toward one side in a prescribed direction that is a surface direction of the non-woven fabric. | 3 |
BACKGROUND OF THE INVENTION
[0001] The header for a pacemaker and method to replace a pacemaker relate generally to medical devices for the heart and more specifically to the header of a pacemaker. A human heart has four chambers that operate in a sequence to both pump oxygenated blood throughout the body and to pump deoxygenated blood to the lungs. The heart musculature provides the compression of the chambers to expel and to collect blood in a pumping action. Electrical signals regulate and time the sequence of heart muscle contractions. The electrical signals operate upon direct current created by the body. As a heart ages, suffers from certain degenerative diseases, or endures trauma, the electrical signals become interrupted or cease completely. Interrupted signals manifest as dizziness or black outs and cessation of signals may appear as a heart attack. Interrupted or ceased signals can cause severe complications to a person.
[0002] As a remedy, medicine has developed the pacemaker. The pacemaker supplements and in some cases replaces the natural electrical signals to the heart muscle. Following diagnosis of a diseased heart suitable for pacing, a surgeon schedules a patient for installation of a pacemaker. A pacemaker has a body, commonly called a can, and a header atop the body. The header has one or more holes designed to receive a wire lead. Silicone coated wires, called leads, have sufficient length to connect the pacemaker to the heart. Commonly, the pacemaker is surgically implanted under the skin directly adjacent to one of the clavicles on the pectoral muscle.
[0003] Two different electrical circuits are programmable into the pacemaker: bipolar and unipolar. A bipolar circuit involves depolarizing the heart by current flow from the negatively charged lead tip to a proximal ring electrode located approximately one centimeter from the negative tip. A unipolar circuit depolarizes the heart as the current flows from the lead tip back to the can. The surgeon inserts the leads into the holes following the pacemaker manufacturer's instructions. The leads pass through channels and reach setscrews in the header. With a lead through a setscrew, a surgeon turns the setscrew with a surgical hex head wrench. After securing all leads to the pacemaker, the surgeon tests the pacemaker and places the pacemaker in final position within a patient. The surgeon then closes the incision.
[0004] Like other artificial devices, pacemakers have a limited lifespan. From time to time, a pacemaker requires adjustment, power source changing, or replacement. In those situations, a surgeon opens a patient and manipulates the leads, the can, the header, and the pacemaker. A patient may lose consciousness, suffer a seizure, endure brain damage, or perish if the heart muscle lacks more than approximately five seconds of electrical signaling. During installation or adjustment of a cardiac pacemaker in a patient or over time, the patient may become pacemaker dependent where the heart can not function without the pacemaker. Surgeons remain conscious of this time interval and risk of dependency as they manipulate the leads and pacemaker. Inserting and removing leads in channels and turning setscrews in a short time heightens the stress upon surgeons and their teams and the risks to the patient.
DESCRIPTION OF THE PRIOR ART
[0005] The prevalence of cardiovascular disease increases demand for pacemakers and spurs their development. With heightened pacemaker demand, the frequency and numbers of patients depending on their pacemakers also rises. Surgeons hone their skills at pacemaker installation and maintenance, and manufacturers develop pacemakers constantly. Modification of pacemakers and their methods of use are known in the prior art.
[0006] The patent to Stutz, U.S. Pat. No. 4,764,132, shows a pair of set screws connecting both the tip and ring electrodes of a lead to a pacemaker header. Similar to the present invention, this patent discloses a single lead connection to a pacemaker header. However, this patent lacks a hole at the end of the lead chamber, a removable cap upon the hole, and a stiff wire to assist in changing a pacemaker.
[0007] The patent to Osypka, U.S. Pat. No. 4,774,951, shows a pacemaker with a silicone like membrane for a needle or tube to access an installed pacemaker lead. Similar to the present invention, this patent has wires inserted through an opening in a pacemaker header. In contrast to the present invention, this patent does not describe end holes with caps nor a method to changeover a pacemaker.
[0008] The patent to Crawford, U.S. Pat. No. 4,848,346, has circular springs that grasp bi-polar leads. Similar to the present invention and Stutz's '132 patent, this patent discloses a pacemaker head with a chamber for a lead. Different from the present invention, this patent focuses upon the connection of the lead to the pacemaker. Buttons that deform the springs allow quick installation of leads.
[0009] The patent to Saell et al., U.S. Pat. No. 4,840,580, shows another connection of leads to a pacemaker. The connection is tangential to a lead. The present invention shares a chamber in the pacemaker header with this patent. However, this patent emphasizes the connection of a lead to a pacemaker with a screw. The screw may have an eccentric cam or a deformable sleeve to grasp a lead.
[0010] Then the patent to Stutz, U.S. Pat. No. 5,007,864, shows how an adapter occupies the chamber in a pacemaker header and receives leads of lesser diameter. Unlike the present invention, a tubular adapter with a set screw distinguishes this patent from the present invention. Further, this patent omits a stiff wire and a hole with a cap at the other chamber end.
[0011] The patent to Wiklund et al., U.S. Pat. No. 5,431,695, shows a pacemaker with a lid surrounded by a shroud with internal pacemaker circuitry. Similar to the present invention, this patent has an entry near the head of the pacemaker for leads. In contrast to the present invention, this patent has a two piece housing with circuitry made separately, no hole opposite the entry and no cap upon the hole.
[0012] The patent to Byland et al., U.S. Pat. No. 5,456,698, has a lid upon a shield forming a pacemaker. Like Wiklund's '695 patent and the present invention, a chamber accepts a lead. Unlike the present invention, the pacemaker has a lid less than the width of the shield, a single chamber, no cap upon the chamber, no discussion of a method to bypass the pacemaker, and the lead gets tied off by sutures.
[0013] The patent to Bemurat, U.S. Pat. No. 5,480,419, describes a specially constructed lead with a branch. This patent describes dependent patients as the recipients of the patented lead much like the present invention. However, this patent has a lead alone and does not mention a hole in the pacemaker header nor a stiff wire bypass of the lead.
[0014] The patent to Reuben et al., U.S. Pat. No. 5,535,097, has the same specification, as Wiklund's '695 patent. Unlike the present invention, a feedthrough admits wire and a single entrance admits leads into the pacemaker.
[0015] Then the patent to Fain et al., U.S. Pat. No. 5,679,026, has an adapter, holding multiple leads in a gang, that mates with a header upon a pacemaker. Like the present invention, this patent has multiple holes. However, the multiple holes are on one side, and the patent omits a stiff wire and a bypass method.
[0016] The patent to Flynn et al., U.S. Pat. No. 5,899,930 has a pacemaker header that receives three or more leads. Akin to the present invention, this patent adapts a pacemaker header for a lead condition: the number of leads. In contrast to the present invention, this patent has holes on one side without caps, side mounted chambers for electrical connections, and no separate wire and method to bypass the pacemaker.
[0017] The second patent to Flynn et al., U.S. Pat. No. 5,906,634 shows a pacemaker that lacks a header but has a special coupling. Like the present invention, this patent seeks a simple connection of the lead to the pacemaker. Unlike the present invention, this patent omits the header and through chamber with opposite holes upon the header, and does not discuss a wire bypass method.
[0018] The patent application to Pasternak, No. 2003/0,040,784, describes an adapter that stores and electrically isolates the ends of leads outside a patient. Like the present invention, this application tackles the delay problem with handling cardiac leads, and in addition reduces the risk of electrocution and confusion from leads upon the skin surface. Differing from the present invention, this adapter has no pacemaker like header and no channel with opposing holes.
[0019] The present invention overcomes the difficulties of installation and manipulation of leads in existing pacemakers and their headers and allows no more than five seconds without a heart beat in a patient.
SUMMARY OF THE INVENTION
[0020] Generally, the present invention provides a modified header to a conventional pacemaker and a method to replace a pacemaker so modified without interrupting pacing. The pacemaker with a modified header starts with a conventional pacemaker having a power source, control circuitry, and a case containing the power source and the control circuitry commonly called a can. The header atop the case has one or more bores upon one end as in a conventional header and one or more hollow wire leads entering the holes and advancing through setscrews. Here, the pacemaker with a modified header has additional holes, caps upon the additional holes, and a separate stiff wire. The additional holes are located opposite the conventional bores. The caps form a watertight seal upon the additional holes. The stiff wire has a diameter suitable for insertion in the core of a wire lead and no beaded end. Using the pacemaker with a modified header and the present method, a surgeon opens a patient having the pacemaker, removes the cap, inserts the stiff wire through the additional hole into the hollow center of a lead, connects an alternate pacing device, and then removes the pacemaker without significant interruption of pacing to the patient.
[0021] There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood and that the present contribution to the art may be better appreciated. Additional features of the invention will be described hereinafter and which will form the subject matter of the claims attached.
[0022] Numerous objects, features and advantages of the present invention will be readily apparent to those of ordinary skill in the art upon a reading of the following detailed description of the presently preferred, but nonetheless illustrative, embodiment of the present invention when taken in conjunction with the accompanying drawings. Before explaining the current embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
[0023] One object of the present invention is to provide a new and improved header for a pacemaker and method to replace a pacemaker.
[0024] Another object is to provide such a pacemaker header that is easy to assemble and to connect to leads.
[0025] Another object is to provide such a method that is swiftly performed with minimal error by a surgeon.
[0026] Another object is to provide such a method that maintains cardiac pacing without significant interruption.
[0027] These together with other objects of the invention, along with the various features of novelty that characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated a preferred embodiment of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 shows a front view of the preferred embodiment of the pacemaker header constructed in accordance with the principles of the present invention attached to a bipolar lead;
[0029] FIG. 2 shows a side view of the preferred embodiment of the pacemaker header;
[0030] FIG. 3 shows a front view of the pacemaker header with the plug removed and the stiff wire inserted into the lead;
[0031] FIG. 4 illustrates the connection of an analyzer to the stiff wire away from the pacemaker header;
[0032] FIG. 5 shows an analyzer wire moved forward of the pacemaker and connected to the stiff wire in preparation for pacemaker removal;
[0033] FIG. 6 shows an analyzer connected to the stiff wire and to the body assuming pacing with the pacemaker removed;
[0034] FIG. 7 shows a front view of an alternate embodiment of the pacemaker header for atrial and ventricular leads constructed in accordance with the principles of the present invention;
[0035] FIG. 8 shows a side view of the alternate embodiment of the pacemaker header;
[0036] FIG. 9 shows a front view of the pacemaker header with the plug removed and the stiff wire inserted into the ventricular lead and a second analyzer connected to the atrial lead;
[0037] FIG. 10 illustrates the connection of an analyzer to the stiff wire upon the ventricular lead away from the pacemaker header with the second analyzer connected to the atrial lead;
[0038] FIG. 11 shows an analyzer wire moved forward of the pacemaker and connected to the stiff wire on the ventricular lead in preparation for pacemaker removal with the second analyzer connected to the atrial lead; and,
[0039] FIG. 12 shows an analyzer connected to the stiff wire upon the ventricular lead and to the body and a second analyzer connected to the atrial lead and assuming pacing with the pacemaker removed.
[0040] The same reference numerals refer to the same parts throughout the various figures.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0041] The present art overcomes the prior art limitations by providing a hole in the header primarily for the ventricle lead opposite the existing bore and a stiff wire for continuing pacing during manipulation of the pacemaker. Beginning on FIG. 1 , the preferred embodiment of the pacemaker 1 header 3 connects with a single bipolar lead 6 . The pacemaker 1 has a can 2 with a power source, control circuitry, and wiring. Upon the top of the can 2 , the header 3 has a generally rectangular shape of cross section similar to the can 2 . The header 3 has an entrance bore 4 to admit a lead 6 into a channel 11 . The channel 11 follows the longitudinal axis of the header 3 through the setscrew 7 . The setscrew 7 is perpendicular to the channel 11 and has a head accessible upon the exterior of the pacemaker 1 . The head of the setscrew 7 has a hexagonal depression to receive an Allen wrench for turning. The setscrew 7 has a hole that receives the lead 6 . The lead 6 has an exposed tip that completes an electrical circuit with the setscrew 7 . The setscrew 7 has an electrical connection with the remainder of the pacemaker 1 . Beyond the setscrew 7 , the channel 11 extends through the header 3 terminating in the hole 8 of the present invention. A cap 9 seals the hole 8 until needed. The hole 8 has sufficient diameter to admit the tip of the lead 6 but not the outer diameter of the lead 6 .
[0042] Turning a pacemaker 1 in FIG. 2 , the present invention has a centered hole 8 in the header 3 opposite the entrance bore 4 . The entrance bore 4 and the centered hole 8 form a channel 11 between them for a lead 6 . The centered hole 8 is generally round with a removable cap 9 filling the hole 8 .
[0043] FIG. 3 shows the first step in using the present invention with the replacement method. To install or to replace a pacemaker 1 , a surgeon opens the patient and ascertains the pacemaker 1 . The surgeon lifts the pacemaker 1 with connected leads 6 outside of the patient. The surgeon places the pacemaker 1 upon the patient's chest and pulls the removable cap 9 to open the channel 11 to the lead 6 . Typically a lead 6 has a hollow cross section encased in a sheath. The surgeon then inserts a straight stiff wire 10 through the centered hole 8 and the setscrew 7 and into the lead 6 . The stiff wire 10 lacks beads to allow use of either end. With the stiff wire 10 into the lead 6 , the surgeon reaches FIG. 3 .
[0044] In addition to pacemakers 1 , cardiac medicine has analyzers 12 that test and monitor pacemaker 1 operations. Analyzers 12 function as temporary pacemakers 1 while a surgeon manipulates a pacemaker 1 for a patient. An analyzer 12 is fixed equipment with a display and wires 12 a , 12 c to connect with a pacemaker 1 and patient. Next, in FIG. 4 , the surgeon clips one analyzer wire 12 a to the end 12 b of the stiff wire 10 away from the pacemaker 1 and a second analyzer wire 12 c to the patient's tissue 12 d . The clips are of the alligator type, operable by a squeeze of the surgeon's fingers and thumb. Thus the surgeon forms a parallel circuit with the operating pacemaker 1 .
[0045] Then the surgeon moves the pacemaker 1 off the lead 6 and onto the stiff wire 10 . The surgeon unclips and moves the first analyzer wire 12 a ahead of the pacemaker 1 . The surgeon then clips the first analyzer wire 12 a to the stiff wire 10 again while the second analyzer wire 12 c remains in place as shown in FIG. 5 . Squeezing the alligator clip, the surgeon readily moves the first analyzer wire 12 a in less than five seconds with minimal risk to the patient.
[0046] In FIG. 6 , the surgeon leaves the analyzer 12 and its two wires 12 a , 12 c in place to assume pacing of a patient's heart. The surgeon then removes the pacemaker 1 and replaces it with another pacemaker 1 by reversing these steps. The analyzer 12 provides pacing without interruption to the patient.
[0047] The preceding FIGS. have described a single lead 6 connecting to a pacemaker 1 header 3 and method to manipulate that lead 6 . Later FIGS. show two leads 6 , 6 A connected to the header 3 : a ventricular lead 6 and an atrial lead 6 A. As in FIG. 1 , the pacemaker 1 of FIG. 7 has a can 2 with a power source, control circuitry, and appurtenant wiring. Upon the top of the can 2 , the header 3 has a generally rectangular shape of cross section similar to the can 2 . The header 3 has two entrance bores 4 to admit the leads 6 , 6 A into two parallel Channels 11 . The channels 11 follow the longitudinal axis of the header 3 through two setscrews 7 . The setscrews 7 are perpendicular to the channels 11 and have heads accessible upon the exterior of the pacemaker 1 . The head of a setscrew 7 has a hexagonal depression to receive a wrench for turning. The setscrew 7 has a hole that receives the lead 6 , 6 A. The lead 6 , 6 A has an exposed tip that completes an electrical circuit with the setscrew 7 . The setscrew 7 connects electrically with the remainder of the pacemaker 1 . Beyond the setscrew 7 , the channel 11 for the ventricular lead 6 extends through the header 3 terminating in the hole 8 of the present invention. A cap 9 seals the hole 8 until needed. The hole 8 has sufficient diameter to admit the tip of the lead 6 but not the outer diameter of the lead 6 . The channel 11 for the atrial lead 6 A proceeds slightly past the setscrew 7 and stops.
[0048] Turning to FIG. 8 , the present invention has a centered hole 8 in the header 3 opposite the entrance bore 4 and beneath the channel 11 for the atrial lead 6 A. The centered hole 8 and ventricular channel 11 are closer to the center of the pacemaker 1 than the atrial channel 11 . The entrance bore 4 and centered hole 8 form a channel 11 between them for the ventricular lead 6 . The centered hole 8 is generally round with a removable cap 9 filling the hole 8 .
[0049] FIG. 9 shows the first step in using the present invention with the replacement method for a two lead 6 pacemaker 1 . To install or to replace a pacemaker 1 , a surgeon opens the patient and finds the pacemaker 1 . The surgeon lifts the pacemaker 1 with connected leads 6 outside of the patient. The surgeon places the pacemaker 1 upon the patient's chest and connects an analyzer 13 to the atrial lead 6 A. The first wire 13 a of the analyzer 13 connects to the tip 13 b of the atrial lead 6 A and the second wire 13 c of the analyzer 13 connects to the proximal ring electrode 13 d of the atrial lead 6 A. The analyzer 13 now provides pacing for the atria of the patient's heart. Meanwhile, the surgeon pulls the removable cap 9 to open the channel 11 to the ventricular lead 6 . The surgeon then inserts a stiff wire 10 through the centered hole 8 and the setscrew 7 and into the ventricular lead 6 . The stiff wire 10 lacks beads to allow use of either end. With the stiff wire 10 into the lead 6 , the surgeon attains FIG. 9 .
[0050] Next, in FIG. 10 , the surgeon clips a third analyzer wire 12 a to the end 12 b of the stiff wire 10 away from the pacemaker 1 and a fourth analyzer wire 12 c to the patient's tissue 12 d . The clips are of the alligator type, operable by a squeeze of the surgeon's fingers and thumb. Thus the surgeon forms a parallel circuit with the operating pacemaker 1 and provides pacing for the ventricles of the patient's heart using an analyzer 12 .
[0051] Then the surgeon moves the pacemaker 1 off the ventricular lead 6 and onto the stiff wire 10 . The surgeon unclips and moves the third analyzer wire 12 a ahead of the pacemaker 1 . The surgeon then clips 12 b the third analyzer wire 12 a to the stiff wire 10 again while the fourth analyzer wire 12 c remains in place as shown in FIG. 11 . Squeezing the alligator clip, the surgeon relocates the third analyzer wire 12 a in less than five seconds with minimal effect upon the patient. The first analyzer 13 provides pacing for the patient's atria and the second analyzer 12 provides pacing for the patient's ventricles.
[0052] In FIG. 12 , the surgeon leaves the analyzers 12 , 13 and their four wires 12 a , 12 c , 13 a , 13 c in place to assume pacing of a patient's heart. The surgeon then removes the pacemaker 1 and replaces it with another pacemaker 1 by reversing these steps. The analyzers 12 , 13 pace the patient's heart without interruption of cardiac signals during the present method.
[0053] From the aforementioned description, a pacemaker header and method to replace same have been described. The pacemaker header is uniquely capable of providing a channel open on both ends to receive cardiac leads and a stiff straight non-beaded wire to assist in changing pacemakers without interruption of electrical signals to the cardiac musculature. The pacemaker header and its various components may be manufactured from many materials including but not limited to stainless steel, polymers, high density polyethylene HDPE, polypropylene PP, polyvinyl chloride PVC, nylon, ferrous and non-ferrous metals, their alloys, and composites.
[0054] As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. Therefore, the claims include such equivalent constructions insofar as they do not depart from the spirit and the scope of the present invention. | A pacemaker with a header and method to replace the header has a can containing a power source and control circuitry and a header to connect with leads. The leads connect to the cardiac musculature and provide electrical signals to pace heart beats properly. The header has a bore through which to admit a lead into a channel. The channel passes through the header to a centered hole opposite the bore. A removable plug closes the hole until a surgeon seeks to open it. To replace a pacemaker, a surgeon finds the pacemaker and removes the plug. The surgeon inserts a stiff wire through the hole and into the lead. After connecting an analyzer to the lead, the surgeon removes the pacemaker without an interruption of cardiac signaling to the patient. The centered hole and stiff wire for replacement also apply to pacemakers with two or more leads. | 0 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The field of the invention is devices utilized in toilet water reservoir tanks which allow for a partial or full flush of the toilet, the partial flush achieved by limiting the water draining from the reservoir tank into the toilet bowl.
2. Description of the Related Art
Inasmuch as many parts of the United States, and especially the West and the Southwest regions, experience water supply shortages, it has now become very popular to conserve water by reducing water usage. To this end, the toilets found in residences and businesses are being modified to provide for a smaller flush, i.e., the water reservoir tank is being reduced from a five gallon capacity to a two to three gallon capacity. In addition, many devices and inventions are coming forth which permit the user to effect a partial or "mini" flush wherein only a portion of the water held in the reservoir tank is utilized. Experience tends to indicate that a partial flush operates satisfactory for liquid wastes, however, in most cases, a partial or "mini" flush is not satisfactory to remove solid wastes. Accordingly, many of the devices which provide for a partial or "mini" flush also provide for a full flush, the choice being made at the time of use.
One such device is shown in the U.S. Pat. No. 4,149,283 to Knudtson. Here a rather complicated mechanism allows selective manipulation of the toilet tank handle to vary the time that a buoyant drain valve takes to re-seat after the flush is first begun, thus allowing only a part of the contained water to exit the tank.
Another device is shown in the U.S. Pat. No. 3,955,218 to Ramsey, wherein a partial or mini flush is provided for utilizing an air venting hole in the upper region of a bell shaped flapper valve but below its annularly shaped sealing flange. As the outside handle is pushed down, the flapper valve is pulled upward, the flapper valve is pulled upward and pivoted off the valve seat, entrapped air within an inverted bell shaped cavity of the flapper valve is allowed to escape through the air venting hole. It is this entrapped air within the bell shaped cavity that renders the flapper valve buoyant and keeps it from re-seating immediately upon the valve seat. The bell shaped cavity has an opening at its lower end. As air escapes from the cavity, a point is reached where the flapper valve is no longer buoyant in the water, and it returns to the valve seat. The size of the hole is adjusted to regulate the rate of release of air from the contained cavity or plenum over time so that not all the water exits the reservoir tank. A full flush may be accomplished by continuing to hold the outside handle down so that the lever arm attached to the handle continually holds up the flapper valve by a connecting chain.
It is noted that the air vent hole in the flapper valve is placed below the annular flange of the flapper valve which actually seals to the valve seat, otherwise, the vent hole would allow continual escape of water from the reservoir tank.
Lastly, Sullivan, in U.S. Pat. No. 4,145,774 provides for a limited or mini flush by providing the handle of the flush mechanism so constructed that if a limited or mini flush is desired, the handle, after being pushed down, must be manually returned to its pre-flush position by the operator. By such action, the interior flapper valve is freed from action upon it by the lever arm in order that it may return to its seated position after a specified time. Return of the flapper valve to its seated position is accomplished by substantially utilizing the invention of Ramsey wherein air entrapped in the interior plenum or cavity of the bell shaped flapper valve may progressively escape. To effect a normal full flush in Sullivan's device, the operator pushes the handle down at the beginning of the operation. The handle returns to its normal pre-flush position after all the water in the tank has drained.
The above devices certainly accomplish their desired purposes; however, the device of Knudtson incorporates rather extensive, complicated, and costly equipment while Sullivan incorporates a rather complicated handle. The device of Ramsey, which appears to be the simpler of the devices, provides for a mini or partial flush, however, the amount of water which is allowed to drain into the toilet bowl is not controlled with precision, it only being a function of how long it takes for sufficient air to escape from the cavity of the flapper valve non-buoyant so that it returns to its seated position terminating the outflow of water. Such operation of the invention is largely controlled by the size of the air vent hole and whether or not it becomes clogged.
In view of the foregoing, it would be useful to provide a simple device which allows for a full flush or a partial flush of a toilet at the option of the user at the time of use. In particular, it would be particularly useful if the amount of water which is to be incorporated in the partial flush be determined with relative precision and repeatable from flush to flush.
SUMMARY OF THE INVENTION
The embodiment of the invention describes consists of a conventional bell type flexible rubber flapper valve used commonly in connection with toilets, the flapper valve modified to permit the air normally entrapped in the cavity or plenum of the flapper valve to escape under controlled conditions. The escape of air from the flapper valve bell shaped internal cavity is controlled in the invention as a function of the level of water in the toilet reservoir tank rather than how fast the air can escape from a vent hole in the flapper valve.
More particularly, one end of a piece of flexible tubing operably connects to the bell shaped flapper valve to place the air passageway of the tubing in communication with the interior cavity which the other end of the flexible tubing connects to the one closed end of a cylinder with its open end residing downward in the water of the reservoir tank. The cylinder may be wholly or partially in the water. The cylinder, being open at its lower end, allows for entrance of water into its cavity. The water level in the cylinder maintains the same height as the level in the reservoir tank which means that the cylinder may be wholly full of water (depending upon its location). The flexible tubing must, however, rise out of the water at some point between its connection with the flapper valve and the cylinder.
When the toilet flush handle lever arm, connected by chain to the flapper valve, lifts the flapper valve as the toilet is being flushed, the flapper valve pivots upward to a position over the valve seat, terminating the seal between the flapper valve flange and the valve seat, and thus allows the water entrapped in the reservoir tank to exit the tank through the central opening of the valve seat and into the toilet bowl.
Under normal conditions and prior to application of the invention to the toilet, the flapper valve remains above the valve seat by virtue of the fact that air entrapped in the bell shaped plenum central to the flapper valve renders the valve buoyant. Then, as the water level drops, the flapper valve returns to seat on the valve seat, the flapper valve sealing its flange around the valve seat as the water level is at or about the valve seat height.
In the invention, air entrapped in the bell shaped plenum of the flapper valve is allowed to controllably escape through the flexible tubing into the upper portion of the cavity of the cylinder. The water level in the cylinder drops consonant with the water level in the reservoir tank, thus pulling or sucking the air from the bell shaped plenum of the flapper valve, making the flapper valve less and less buoyant. Of course, water is under pressure to enter the bottom opening of the inverted bell shaped cavity of the flapper valve and thereby helps push the air out of the cavity. When sufficient air has been sucked and pushed from the flapper valve cavity to render the flapper valve non-buoyant, the flapper valve returns to its position on the valve seat and terminates the flow of water.
The level at which the flapper valve returns to the valve seat is determined by a number of factors which can work together or independently of each other. The first is the position of the cylinder in the tank relative to the water level such that as the water level in the cylinder falls with the water level in the tank, the point at which the flapper valve closes is carefully controlled. The second factor is the volume of the contained cavity of the cylinder. Lastly, the location of the rim of the open end of cylinder factors into the operation of the device. Through use of these factors, control of the volume of water used in the partial flush is repeatedly achieved.
Concerning the second factor and third factor, if the volume of the cylinder is too small to receive sufficient air from the flapper valve to render it non-buoyant, the cylinder is positioned such that the flapper valve will drop to the valve seat first as the water level clears the bottom rim of the cylinder open end by virtue of the fact that the air in the flapper valve can now rush out of the bottom of the cylinder.
Other embodiments include attaching a sharpened piece of rigid tubing to the first end of the flexible tubing, the sharpened end of the rigid tubing used to puncture the rubber flapper valve much like a hypodermic needle. In a case such as this, the need to form an opening in the upper portions of the flapper valve to receive the rubber tubing is avoided or the need to form a protruding tube in the flapper valve which mates with the flexible tubing.
In addition, a still further embodiment avoids the use of a cylinder whereby the second end of the flexible tubing becomes the cylinder itself. In such a case, the air in the flapper valve cavity exits the flexible tubing when the water level in the tank has passed just below the open end of the flexible tubing.
Lastly, a holder is provided to secure the flexible tubing at a point between the flapper valve and the cylinder, preferably proximate its second end joining the cylinder. The holder may rest upon the top lip of the tank, securing the flexible tubing at a point out of the water.
In the event that a full flush is desired, all the operator need do is to keep the flush handle continually depressed for the whole flush, thus causing all the water in the reservoir tank to run out. In doing so, the lever arm connected by the chain to the flapper valve holds the flapper valve above the valve seat so that, even though the flapper valve becomes non-buoyant, it is still forcibly held above the valve seat.
Accordingly, it is an object of the present invention to provide a simple device which permits for a partial flush of a toilet.
It is another object of the subject invention to provide a simple device which provides for a specific volume of water to be used in a partial flush of a toilet, and which operation is repeatable.
It is still another object of the subject invention to provide a simple device for effecting a partial flush of a toilet wherein the present existing elements of the toilet are employed with minor modifications.
Other objects of the invention will in part be obvious and will in part appear hereinafter. The invention accordingly comprises the apparatus possessing the construction, combination of elements, and arrangement of parts which are exemplified in the following detailed disclosure and the scope of the application which will be indicated in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
For further understanding of the features and objects of the subject invention, reference should be made to the following detailed description taken in combination with the accompanying drawings wherein:
FIG. 1 is a partial cross sectional view of a typical toilet reservoir tank with the invention in place;
FIG. 2 is a partial cross sectional view of a typical toilet reservoir tank with the invention in use;
FIG. 3 is a partial cross sectional view of an alternate embodiment of the invention;
FIG. 4 is a perspective view of the device of the invention prior to installation in a toilet; and
FIG. 5 is a partial cross sectional view of another alternate embodiment of a portion of the device of the invention.
In various views, like index numbers refer to like elements.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, a cross sectional view of a portion of toilet water reservoir tank 8 with the invention in place is shown. Central to bottom 14 of the tank 8 is valve seat 16 through which the water in the tank drains when float or flapper valve 18 is raised by chain 20 attached to the end of lever 22. Lever 22 is attached to flush handle 23. Water is shown in the tank having a level 24, being the normal full level. The above described elements are common in toilet tanks and control the flow of water through the outlet 26 and into the bowl (not shown) of the whole toilet assembly when the toilet is flushed. To effect a flush of the standard usual toilet, lever 22 is raised by rotation of handle 23 (on the outside of the toilet tank), Chain 20 attached to lever 22 pulls flapper valve 18 off seat 16 by pivoting it upwards. With flapper valve 18 off seat 16, water flows through the center opening of seat 16 and out outlet 26. Flapper valve 18, once lifted off seat 16, is buoyant and is suspended in the water above seat 16 by virtue of air trapped inside an inverted bell shaped interior cavity of valve 18.
As the water level 24 subsides in the unmodified standard toilet, flapper valve 18 eventually falls and reclaims its original position with its annular flange 21 sealing to seat 16 and thus terminates the flow of water through seat 16 and outlet 26.
During the flush operation, a float operated valve (not shown) allows new water to flow into toilet reservoir tank 8 so that even during discharge of the present water in the tank, new water is being introduced, although at a slower rate. When flapper valve 18 is re-sealed on seat 16, incoming water begins to fill reservoir tank 8 until the water reaches its usual level, i.e., the level shown by level 24. At that time, the float operated valve (not shown) cuts off the flow of incoming water.
The invention, a device used to effect a partial flush and shown by numeral 10, resides in the water tank and incorporate flapper valve 18. More specifically, partial flush device 10 comprises modified flapper valve 18, flexible plastic or rubber tubing 30, plastic or metal cylinder 32 and plastic or metal tubing holder 34. The air passageway interior to flexible tubing 30 communicates the interior cavity or plenum of the bell shaped portion of flapper valve 18 to the top closed end of cylinder 32, the bottom end of cylinder 32 being open. To enable flexible tubing 32 to communicate with the interior of flapper valve 18, opening 17 has been made through the top wall of flapper valve 18 above flange 21, preferably in the front portion of the cavity since, as it will be seen later, air within the interior cavity of flapper valve 18 is evacuated. To assure that sufficient air is evacuated to render the flange valve non-buoyant, it may be necessary to remove substantially all of the air. Placing hole or opening 17 in the portion of the wall of flapper valve 18 farthest away from the hinged portion 19 is recommended since the last remaining air interior to flapper valve 18 accumulates there during the time the flapper valve is buoyant.
Penetration through opening 17 in the top wall of flapper valve 18 may be made by flexible tubing 30 inserted into the opening. A proper adhesive should be used to make the connection air tight, or a short piece of rigid plastic tubing may be inserted through the formed opening in flapper valve 18 and then flexible tubing 30 secured on the outside of that rigid tubing. It is recommended that an adhesive be used to render all joints air tight.
Alternately, a short stem with an air passageway may be molded into flapper valve 18 during manufacture. In such case, flexible tubing 30 is attached to the stem by any one of a number of obvious methods.
Flexible tubing 30 then rises up and out of the water, above water level 24, is secured to holder 34, and then enters closed end 36 of cylinder 32. Flexible tubing 30 may be attached to cylinder 32 by similar methods used to attach the tubing to flapper valve 18, i.e., tubing 30 may protrude just slightly interiorly to cylinder 32 through an opening formed in top end 36. A proper adhesive should be used to assure that the connection is air tight. Alternately, a short piece of rigid tubing having an air passageway may extend outward from top end 36 of cylinder 32, flexible tubing 30 then encompassing that short piece of rigid tubing. The bottom of cylinder 32 is open in order that water from the tank may enter the cylinder.
Flexible tube holder 34 secures the tubing in such a way to secure cylinder 32 in the position shown and such that cylinder 32 does not move as a water level 24 moves up and down. Alternately, cylinder 32 may be made of heavy material, such as a metal or thick walled plastic, so that it is not buoyant in water and continually pulls down on tubing holder 34 by pulling on flexible tubing 30. Lastly, the position of cylinder 32 is adjusted up or down in the toilet tank by positioning flexible tubing 30 on holder 34. Holder 34 may be a piece of metal or plastic sheet, formed as shown to cup over the top of the vertical wall 12 of tank 8, having an outstanding horizontal plate with an opening therethrough to receive the flexible tubing. If the opening through holder 34 is only slightly smaller than the tubing, there will be sufficient friction to secure the tubing in place and to suspend cylinder 34.
The toilet flush in a standard or regular toilet is initiated when lever 22 is raised by rotating downward handle 23 on the outside of the toilet tank. This causes flapper valve 18 to pivot upward and off valve seat 16. Water stored in the tank reservoir then commences to flow through the center opening of seat 16 and out outlet 26. If lever 22 is continually held up, all the water in the toilet tank above valve seat 16 will flow through outlet 26, including water incoming into the tank. Releasing lever 22 permits annular flange 21 of flapper valve 18 to return to its sealing position atop valve seat 16 and water then begins to refill the tank. This is the standard full flush.
The invention works in conjunction with flushing mechanism as follows. If lever 22 is raised causing flapper valve 18 to pivot off seat 16 and handle 23 is released, lever 22 falls to its original at rest position. Flapper valve 18, however, is buoyant and floats in the water above valve seat 16. Buoyancy of flapper valve 18 is due to the air entrapped inside the interior cavity or plenum of the bell shaped portion of the flapper valve. The bottom of flapper valve 18 is open which allows water to enter the interior cavity of flapper valve 18 as the air is removed. By removing air interiorly to flapper valve 18, flapper valve 18 will reach the point where it is no longer buoyant and then it will settle back upon seat 16 to terminate flow of water through outlet 26.
The next task is to regulate the point in the flushing process where flapper valve 18 is no longer buoyant and returns to its seated position. By doing so, the flush is terminated resulting in a partial flush. This is accomplished by means of the flexible tubing 30 communicating the interior cavity of flapper valve 18 to the interior cavity of cylinder 32.
Firstly, as water fills tank 24 after a flush operation, water will enter the open bottom of cylinder 32 and rise to the same level as that of water level 24. As shown in FIG. 1, the water would rise in cylinder 32, completely filling it, and then rise to level 25 in flexible tubing 30 attached to the top end 36 of cylinder 32. Water enters cylinder 32 because the air which was inside cylinder 32 bleeds out and down through flexible tubing 30 into the interior of flapper valve 18 and into outlet 26. Thus, there is no impediment to the filling of cylinder 32 by water as the water level rises in the toilet tank reservoir.
Note the requirement that flexible tubing 30 must rise out of the top end of cylinder 32 and above water lever 24 before it re-enters the water for its attachment to flapper valve 18. If tubing 30 did not rise above water level 24, water inside cylinder 32 would continually drain through tubing 30 into the cavity of flapper valve 18 and out outlet 26.
When a partial flush is desired, handle 23 is pushed downward resulting in lever 22 raised to lift flapper valve 18 off seat 16. Handle 23 is allowed to return to its prior position which lowers lever 22. Flapper valve 18, however, being buoyant, remains above seat 16 and the water in the tank reservoir proceeds to enter the central opening of seat 16 and exit outlet 26. As water level 24 falls, water level 25 interiorly to cylinder 32 will also fall, the two levels falling substantially together, any slight difference being due to surface tension of the water around the interior walls of cylinder 32. As the water interiorly to cylinder 32 drops, air must replace it in the top of cylinder 32 and that air is obtained from the interior cavity of flapper valve 18. Thus, cylinder 32 acts as a "suction pump" to pull air from the interior of flapper valve 18.
When water level 24 has fallen sufficiently that enough air has transferred from the cavity of flapper valve 18 to the top of cylinder 32 to render flapper valve 18 non-buoyant, it then returns to its sealing position atop seat 16. Depending upon the diameter of cylinder 32 and its length, i.e., its volume, water level 24 may or may not fall to the bottom rim of cylinder 32 before flapper valve 18 re-seats. If cylinder 32 is particularly short in length and not great in diameter, then once level 24 has fallen below the rim of cylinder 32, air interiorly to the cavity of flapper valve 18 will then rush out at an increased rate through the open end of cylinder 32. It is to be remembered that helping to evacuate air from the upper portion of the cavity of flapper valve 18 is water attempting to enter the bottom opening of flapper valve 18. Thus, in addition to the falling water level in cylinder 32 pulling air from the top of the cavity of flapper valve 18, water entering the bottom opening of flapper valve 18 is also pushing air out.
Referring now to FIG. 2, a second partial cross sectional view of toilet reservoir tank 8 with the invention in place is shown. Here, the flapper valve is elevated in its buoyant position allowing the water in tank reservoir 8 to escape through the central opening of valve seat 16 and outlet 26 into the bowl of the toilet (not shown). It is apparent in FIG. 2 that the new water level 24' is below the former water level 24 (FIG. 1), bringing down water level 25' interiorly to cylinder 32. By the falling of water level 25' in cylinder 32, air is transferred from interiorly flapper valve 18 through flexible tubing 30 into the top of cylinder 32. Thus, the falling of water level 25' in cylinder 32 acts as a "suction pump" to extract the air from the interior plenum of flapper valve 18. Of course, water is always attempting to enter the bottom opening of flapper valve 18 so the combined effect of water sucking and pushing the air out is operating.
Falling water level 24' (and also water level 25') will reach a level at which sufficient air from the interior cavity of flapper valve 18 has been transferred to cylinder 32 so that flapper valve 18 is no longer buoyant. At that point in time, flapper valve 18 will pivot down, re-seating itself on seat 16 and thus terminate the flow of water from tank reservoir 8 out the outlet 26. That point may occur prior to water level 24' falling below the lower circular rim or edge of the open end of cylinder 32. However, if water level falls below the lower circular edge of cylinder 32 and flapper valve 18 has not yet returned to seat 16, the air interiorly to flapper valve 18 will be pushed out by the incoming water and flapper valve 18 will immediately return to seat 16. The air escapes out the bottom of cylinder 32.
Thus, the point at which it is desired the flapper valve 18 to return to its seat vis-a-vis the falling water level in the tank may be easily determined by one of two ways. The first is to control the interior volume of cylinder 32 (i.e., size of cylinder 32) and its relative placement in the tank such that as water level 24' falls taking with it water level 25 interiorly to cylinder 32, the interior volume of cylinder 32 which receives air from flapper valve 18 is sufficient to receive enough air to render flapper valve 18 non-buoyant.
The second method is to use a smaller cylinder 32, but to locate the lower open mouth of cylinder 32 below water at a point in the tank reservoir such that when water level 24' drops below the opening of cylinder 32, contained air in the interior plenum of flapper valve 18 will rush out of cylinder 32 and thus render the flapper valve no longer buoyant, permitting it to return to valve seat 16.
Accordingly, it is apparently obvious that another embodiment of the invention is possible wherein use of cylinder 32 is avoided, and the open end of flexible tubing 30 is merely positioned in the toilet tank below water level 24', but at the appropriate level when the partial flush is to terminate.
More particularly, shown in FIG. 3 is the alternate embodiment above spoken wherein flexible tubing 30 has been extended and secured down into the water below the standing water level 24. Shown in FIG. 3 is fallen water level 24' (in dotted form) to which the water has fallen, now below the open end of flexible tubing 30. At this point, air now may exit the interior plenum of flapper valve 18 (caused by the in-rushing water, FIG. 2) through flexible tubing 30 so that nearly all of the air in the plenum escapes and flapper valve 18 pivots down onto seat 16 wherein flow of water through outlet 26 is terminated. It is noted that in FIG. 3, tubing holder 34 is shown securing tubing 30 at a point above standing water level 24 (tubing holder 34 need not to be above the water, however, flexible tubing 30 must have some portion above the water).
FIG. 4 shows a perspective view of the elements of the invention separated from the reservoir of toilet tank 8. In FIG. 4, shown is flapper valve 18 consisting of an annular flap 21 which actually makes the circular seal around seat 16 (not shown) with pivot arm 52 attached to flapper valve annular flange 21, pivot arm 52 pivotally secured to an upright member situated in the toilet tank (not shown). Flapper valve 18 pivots about an opening in pivot arm 52 through which protrudes a pin attached to the upright member (not shown), flapper valve 18 pivoting above seat 16 and thereby opens the tank reservoir to the exiting water. The upper portion of flapper valve 18 comprises a hemispherical top and the lower portion consists of a bottom cone or inverted bell shaped portion which, when seated on seat 16, resides interiorly to the central opening of valve seat 16. At the lower part of bell shaped portion 56 is opening 58 by which entrance to the interior cavity may be gained. Interiorly to bell shaped portion 56 and hemispherical top 54 is the bell shaped plenum or cavity which contains air to render flapper valve 18 buoyant above seat 16 after it has been lifted off seat 16 by chain 20 attached to lever 22 (not shown).
Protruding interiorly through an opening in the top hemisphere of flapper valve 18 is flexible tubing 30, the interior passageway of which communicates with the plenum interiorly to flapper valve 18. At the other end of flexible tubing 30 is connected the single closed end of open ended cylinder 32, top end 36 being penetrated by tubing 30. Here again, the open passageway of flexible tubing 30 communicates with the plenum interiorly to cylinder 32.
It becomes very apparent that flapper valves 18 commonly available may be utilized for the subject invention without modification if entrance into the interior cavity may be easily gained. Access to the interior cavity is afforded if one end of flexible tubing 30 is connected to a sharpened piece of rigid tubing. Referring now to FIG. 5, to one end of flexible tubing 30 has been added a short piece of rigid tubing 60 which has been provided with a sharpened point, much like a hypodermic needle. This sharpened point is pushed through the soft rubber of flapper valve 18 so as to communicate with the plenum therein. By such means, already existing flapper valves may be utilized to comprise a portion of the invention.
It is also apparent that by adjustment of the relative height position of cylinder 32 (FIGS. 1 and 2) in the toilet reservoir tank, the water used for a partial flush may be varied. For example, locating cylinder 32 at a relatively high elevation in the reservoir tank will result in a partial flush using a relatively small volume of water, such as one gallon. Locating cylinder 32 at a deeper or lower position in the reservoir tank will result in more water utilized in the partial flush, for example, two gallons. It is therefore apparent that the volume of water utilized in a partial flush may be varied from almost no water to all the water in the reservoir tank, i.e., a full flush.
It is also noted that once a full flush has started and the water level passes the partial flush level, the full flush may be terminated by releasing the flush handle since by that time all air has been evacuated from the flapper valve cavity and it is now non-buoyant and will return to the valve seat.
While a preferred embodiment of the device has been shown and described together with alternate embodiments, it will be understood there is no intent to limit the invention by such disclosure, but rather it is intended to cover all modifications and alternate constructions falling with in the spirit and the scope of the invention as defined in the appended claims. | A water saving device for toilets providing both partial flush and full flush capability is disclosed wherein for the partial flush, air is controllably removed from the interior cavity of a flapper valve to render the flapper valve non-buoyant to return it to its sealing position on the valve seat and terminate flow of water out of the reservoir tank. Removal of air from the flapper valve cavity is rendered a function of the dropping water level in the reservoir tank by attachment of one end of flexible tubing to the flapper valve contained air cavity, the other end of the flexible tubing communicating with the interior cavity of a cylinder, the cylinder having one closed end and one open end, the open end residing downward in the water. As water drops in the toilet tank, it also drops in the cylinder and air is sucked from the flapper valve cavity. When the water level drops sufficiently, enough air is removed from flapper valve cavity to render the flapper valve non-buoyant, and the flapper valve returns to its seat, closing off the flow of water out of the tank and into the toilet bowl. Thus a partial flush is effected. A full flush is effected by continually holding up the flapper valve. | 4 |
TECHNICAL FIELD
[0001] This disclosure relates generally to exterior badges for motor vehicles. More particularly, the disclosure relates to an illuminated exterior badge for a vehicle, which illuminates in particular patterns according to particular vehicle functions or signals to be given.
BACKGROUND
[0002] While it is known to provide illuminated exterior badges for vehicles, typically there are regulations dictating particular ways that a badge may be illuminated. For example, conventionally regulations require that anterior (forward) vehicle lighting be a white color, while posterior (rear) lighting is typically red or yellow. Thus, indicating vehicle functions or conditions using a vehicle exterior badge can be hampered by such regulations.
SUMMARY
[0003] In accordance with the purposes and benefits described herein, in one aspect the present disclosure provides an illuminated exterior badge assembly for a vehicle, including a vehicle body surface-mounted badge and a circuit board comprising a plurality of independently actuable sets of light sources. A controller operatively connected to the circuit board is configured to control one or more of an activation sequence or an illumination intensity of the plurality of independently actuable sets of light sources. Typically, the circuit board is disposed beneath the surface-mounted badge. In embodiments, the circuit board includes a first set of light sources emitting a first light color, intensity, and pattern, a second set of light sources emitting a second light color, intensity, and pattern, and a third set of light sources emitting a third light color, intensity, and pattern. In embodiments, the first light color, the second light color, and the third light color may be the same or different. In embodiments, the first light intensity, the second light intensity, and the third light intensity may be the same or different. In embodiments, the first light pattern, the second light pattern, and the third light pattern may be the same or different.
[0004] In another aspect, the present disclosure provides an illuminated exterior badge assembly for a vehicle, including a vehicle body surface-mounted badge and a circuit board underlying the badge and comprising three independently actuable sets of light sources. A controller is operatively connected to the circuit board and configured to control one or more of an activation sequence or an illumination intensity of the three independently actuable sets of light sources.
[0005] In embodiments, on detecting a vehicle start-up condition the controller is configured to incrementally actuate the set of light sources beginning with one or more light sources associated with a center portion of the circuit board and proceeding to a plurality of light sources associated with a perimeter of the circuit board. Conversely, on detecting a vehicle power-down condition the controller is configured to incrementally extinguish the set of light sources beginning with the plurality of light sources associated with the perimeter of the circuit board and proceeding to the one or more light sources disposed in the center portion of the circuit board.
[0006] In other embodiments, the controller is configured to intermittently actuate a second set of light sources on detection of a vehicle malfunction condition, to alternately actuate the second set of light sources and a third set of light sources on receipt of a signal such as from a vehicle key fob, and/or to intermittently actuate the second set of light sources on actuation of a vehicle emergency flasher system.
[0007] In yet another aspect, the present disclosure provides an illuminated exterior badge assembly for a vehicle including a vehicle body surface-mounted badge, a circuit board underlying the badge and comprising a plurality of independently actuable sets of light sources; and a controller. The controller is operatively connected to the circuit board and configured to control one or more of an activation sequence or an illumination intensity of the plurality of independently actuable sets of light sources. In turn, the controller is configured to actuate or extinguish a set of light sources in a predetermined incremental pattern on detecting a vehicle start-up or power-down condition.
[0008] In embodiments, on detecting the vehicle start-up the controller is configured to incrementally actuate the set of light sources beginning with one or more light sources associated with a center portion of the circuit board and proceeding to a plurality of light sources associated with a perimeter of the circuit board. Conversely, on detecting the vehicle power-down condition the controller is configured to incrementally extinguish the set of light sources beginning with the plurality of light sources associated with the perimeter of the circuit board and proceeding to the one or more light sources disposed in the center portion of the circuit board. In embodiments, the controller is configured to incrementally actuate the set of light sources beginning with the one or more light sources associated with the center portion of the circuit board and proceeding to incrementally illuminate light sources in a badge-vertical and a badge-horizontal direction providing a cross-shaped illumination pattern, and then to illuminate the plurality of light sources associated with a perimeter of the circuit board. Conversely, the controller is configured to incrementally extinguish the set of light sources beginning with the plurality of light sources associated with the perimeter of the circuit board and proceeding in the badge-vertical and a badge-horizontal direction to extinguish the one or more light sources disposed in the center portion of the circuit board.
[0009] In the following description, there are shown and described embodiments of the disclosed vehicle illuminated exterior badge. As it should be realized, the device is capable of other, different embodiments and its several details are capable of modification in various, obvious aspects all without departing from the devices and methods as set forth and described in the following claims. Accordingly, the drawings and descriptions should be regarded as illustrative in nature and not as restrictive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The accompanying drawing figures incorporated herein and forming a part of the specification, illustrate several aspects of the disclosed illuminated exterior badge, and together with the description serve to explain certain principles thereof. In the drawing:
[0011] FIG. 1 depicts a vehicle including an exterior badge:
[0012] FIG. 2 depicts an illuminated exterior badge assembly according to the present disclosure;
[0013] FIG. 3 illustrates a representative control schematic for the badge of FIG. 2 ;
[0014] FIG. 4A illustrates a representative activation pattern of the badge assembly of FIG. 2 ;
[0015] FIG. 4B illustrates continued activation of the badge assembly of FIG. 2 ;
[0016] FIG. 4C illustrates continued activation of the badge assembly of FIG. 2 ; and
[0017] FIG. 4D illustrates continued activation of the badge assembly of FIG. 2 .
[0018] Reference will now be made in detail to embodiments of the disclosed illuminated exterior badge, examples of which are illustrated in the accompanying drawing figures.
DETAILED DESCRIPTION
[0019] With reference to FIG. 1 as is known a vehicle badge 10 may be mounted on various vehicle V surfaces, including at a rear end 12 of the vehicle. As shown, the badge 10 is mounted on a rear door 14 of the vehicle V, between a set of running/brake lights 16 . In other embodiments, the badge 10 may be mounted on a front end 18 of the vehicle V, on a side 20 of the vehicle, etc. All such placements are contemplated for the exterior badge assembly disclosed herein.
[0020] As shown in FIG. 2 , the present disclosure describes an illuminated exterior badge 100 including an underlying circuit board 102 including a series of associated light sources. In embodiments, the circuit board 102 is a printed circuit board (PCB). The exterior badge 100 includes an outer shell 101 which in use overlays the circuit board 102 and which may be configured in any desired shape, such as for example an emblem or logo associated with a particular vehicle and/or vehicle manufacturer. As is known, the outer shell 101 may be fabricated of any of a number of suitable materials, may be partially vacuum metalized on an outer surface thereof, may be deadfronted (i.e. of an opaque or semi-opaque plastic), etc. One or more controllers 104 operatively associated with the circuit board 102 in turn control illumination patterns of the light sources.
[0021] The badge 100 and controller 104 are further associated with a power source 105 for providing current to the circuit board 102 and light sources. As will be appreciated, that power source 105 may be a vehicle power source such as a battery, or may be an independent power source associated with the badge 100 . This is shown in greater detail in FIG. 3 , illustrating a control schematic for an exterior illuminated badge 100 including a controller 104 that in the depicted embodiment is a microprocessor including a memory M and at least one processor P. As shown, the controller 104 is further operatively associated with a vehicle control module such as a basic control module (BCM) by way of which certain functions of the illuminated exterior badge 100 as discussed below may be controlled and implemented.
[0022] A variety of light sources may be disposed on the circuit board 102 , in accordance with the light pattern to be displayed and/or the function to be indicated by the illuminated exterior badge 100 . The light sources may be provided by means of a plurality of light-emitting diodes (LEDs) arrayed on the circuit board 102 . Advantageously, this eliminates a need for more complex methods for causing emission of light under and/or through the shell 101 , such as for example light pipes or similar devices, while still providing a controlled, even illumination pattern.
[0023] In an embodiment, a first set of LEDs 106 of a first color and intensity may be arrayed along a perimeter of the circuit board 102 , and also in an interior of the circuit board 102 . As shown, the LEDs 106 are arrayed in a cross-shaped pattern in an interior of the circuit board 102 , and then along the perimeter of the board as described. In turn, additional LEDs may be arrayed in other portions of the circuit board 102 . In the depicted embodiment, a second set of LEDs 108 of a second color and/or a second intensity and a third set of LEDs 110 of a third color and/or a third intensity are disposed in the interior of the circuit board 102 . As will be appreciated, multiple combinations of LED number, color and intensity are possible. In the depicted embodiment, LEDs 106 and 108 emit a same color (white) at a different intensity, while LEDs 108 and 110 emit a different color (red) at a same intensity. Of course, different combinations of LED color and/or intensity are possible and contemplated for use herein. For example, additional LED sets could be included emitting an amber color for a different warning or alert signal.
[0024] In the depicted embodiment LEDs 106 are relatively smaller and/or less intense LEDs emitting white light, and illuminate in a predetermined desired pattern on vehicle start-up as an indicator to the operator that the vehicle (not shown) and its various systems are powering up/powered up. For example (see FIGS. 4A-4D ), on vehicle start-up the controller 104 may cause the LEDs 106 to illuminate in an incremental “inside-out” pattern (see arrows) wherein the illumination of LEDs 106 begins at a center of the LED 106 array ( FIG. 4A ) and proceeds sequentially ( FIGS. 4A-4C ) to provide an X-shaped illumination pattern ( FIG. 4C ). The controller 104 then proceeds to illuminate the perimeter LEDs 106 ( FIG. 4D ). In turn, the LEDs 106 may be extinguished in an incremental “outside-in” pattern from the perimeter LEDs 106 to the interior LEDs 106 on vehicle power-down.
[0025] In turn, LEDs 108 may be provided in the interior of the circuit board 102 that also emit a white light but are capable of emitting an increased wattage compared to LEDs 106 . When the illuminated exterior badge 100 is provided as a rear vehicle badge, such LEDs 108 may illuminate when an operator places the vehicle in reverse, i.e. as auxiliary “backup” lights.
[0026] Still more, LEDs 110 that are of a similar intensity but a different color than LEDs 108 may be provided. In the depicted example, LEDs 110 emit a red color. When used in a badge 100 disposed at a front and/or rear of a vehicle, the red LEDs 110 may serve as auxiliary running lights during vehicle operation, to increase vehicle visibility. For badges 100 disposed both at a front and a rear of a vehicle, the controller 105 may cause LEDs 110 to illuminate intermittently on or after vehicle start-up to indicate a vehicle malfunction or “trouble” condition detected by one or more vehicle sensors, for example a low tire pressure condition, a low oil pressure condition, a high engine temperature condition, a “check engine” code, and others. This is accomplished by an operative association of controller 104 with a vehicle control module such as the BCM. Thus, as the owner starts the vehicle or approaches the vehicle after a remote start-up, she is immediately made aware that there is a potentially problematic vehicle condition that should be investigated.
[0027] Various safeguards may be implemented to guard against excessive heat generation by the badge 100 . For example, on or before illumination of LEDs 108 , LEDs 106 may be extinguished to prevent excessive heat buildup. To further reduce excess heat generation, LEDs 106 , 108 , and/or 110 may be serially connected. Still more, a temperature sensor associated with the microprocessor 104 may be used to determine a temperature of the illuminated exterior badge 100 and/or an ambient temperature adjacent to the vehicle, to prevent excessive heat generation by the badge. As will be appreciated, this arrangement allows a determination of ambient temperature to be factored into calculations determining an amount of current passed to the badge 100 , number of LEDs illuminated, etc. For example, in very high ambient temperatures and/or if the vehicle engine is generating significant heat, less current is passed to the badge 100 and/or fewer LEDs are illuminated, thus reducing the amount of heat generated.
[0028] Of course, additional functions may be implemented by use of the above-described LED arrangement. For example, the controller 104 may cause the LEDs 110 to flash intermittently when the vehicle emergency flashers are actuated, thus further enhancing vehicle visibility. Still more, the illuminated badge 100 may be used as a vehicle finding tool, for example in a crowded parking lot. This may be accomplished by causing the LEDs 108 and/or LEDs 110 to illuminate intermittently when a vehicle operator actuates a “panic” button on, e.g. a key fob or the like, or when a “smart” key is in sufficient proximity to the owner's vehicle. This will draw the operator's attention to his car. As non-limiting examples, under the control of controller 104 the LEDs 108 may flash intermittently, LEDs 110 may flash intermittently, or LEDs 108 and LEDs 110 may alternate flashing intermittently for even more visibility.
[0029] Obvious modifications and variations are possible in light of the above teachings. For example, alternative sequences for activation of one or more of the described sets of LEDs 106 , 108 , 110 by microprocessor 104 are possible. In turn, additional or fewer sets of LEDs of the same or differing colors/intensities may be provide to create alternative illumination patterns and/or intensities. All such modifications and variations are within the scope of the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled. | An illuminated exterior badge assembly for a vehicle includes a vehicle body surface-mounted badge and a circuit board underlying the badge and comprising three independently actuable sets of light sources. A controller is operatively connected to the circuit board and configured to control one or more of an activation sequence or an illumination intensity of the three independently actuable sets of light sources. On detecting a vehicle start-up condition, the controller incrementally actuates the set of light sources beginning with one or more light sources associated with a center portion of the circuit board and proceeding to a plurality of light sources associated with a perimeter of the circuit board. The converse actuation pattern is observed on vehicle power-down. | 6 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority to U.S. Provisional Application Ser. No. 61/102,463, filed Oct. 3, 2008.
FIELD OF THE INVENTION
The present invention generally relates to the production of a fire-resistant cellulose insulation product, and more particularly to the manufacture of fire-resistant cellulose insulation materials using a process which exclusively involves liquid fire retardant compositions.
BACKGROUND OF THE INVENTION
Cellulose compositions combined with fire retardant materials are widely used in the construction industry. Specifically, fire-resistant cellulose materials are traditionally used for thermal insulation in the walls and attic spaces of homes and commercial buildings. Insulation products of this type are designed to prevent heat loss and correspondingly insulate building structures from the outside environment. Raw materials used to produce cellulose insulation products may involve many different paper compositions ranging from recycled newspaper to cardboard, paperboard, and fiberboard. These materials are physically processed to produce a finely-divided material having a low bulk density.
To achieve an approved level of flame and smolder resistance, the selected cellulose materials are combined with fire retardant compositions during the production process. Many different fire retardants may be used for this purpose, which are traditionally applied in powder form. Exemplary fire retardant compositions include but are not limited to monoammonium phosphate, diammonium phosphate, boric acid, ammonium sulfate, sodium tetraborate and mixtures thereof. These materials, as well as other fire retardant compositions and additional information regarding the production of cellulose insulation products are discussed in U.S. Pat. No. 4,168,175 to Shutt and U.S. Pat. No. 4,595,414 to Shutt, the disclosures of which are incorporated herein by reference.
After combining the selected fire retardant compositions and cellulose materials, the resulting product is physically processed using conventional mechanical devices (e.g. hammermill systems known in the art) to produce a pulverized, finely divided insulation product. In accordance with traditional processing technology, fire-resistant cellulose insulation products are specifically prepared using one of two basic methods. In a first method, the selected cellulose materials (e.g. recycled/used paper products) are subjected to multi-stage size reduction by grinding or other conventional processes using standard equipment including but not limited to hammermill systems. At selected stages during the size reduction process, a fire retardant composition in powder (dry) form is combined/mixed with the cellulose materials. In a preferred embodiment, mixing of these ingredients is undertaken at or near the final grinding/shredding stages of the system.
Alternative “hybrid-type” systems have been developed which involve addition of fire retardant compositions in powder (dry) form at or near the final size-reduction stages of the system in combination with the use of a liquid fire retardant composition in the initial stages of production. However, both of these systems require the use of powdered (dry) fire retardant compositions which present numerous disadvantages. These disadvantages include but are not limited to (1) the generation of substantial amounts of dust which requires elaborate safety and environmental control systems; (2) the need to use large amounts of chemicals (e.g. fire retardants) due to production inefficiencies associated with powder-type systems; and (3) increased material costs associated with the need to use large quantities of powdered chemicals.
SUMMARY OF THE INVENTION
The present invention involves a unique and distinctive all-liquid fire retardant system that entirely avoids the use of any fire retardants in powdered (dry) form and produces a low-dust fire retardant cellulose insulation material. The present system includes a combination of process steps which efficiently produces a cellulose insulation product in a highly effective manner while avoiding the problems described above. Furthermore, processes of the invention provide numerous important and substantial advantages not attainable by powder-based systems, including but not limited to (1) the substantial elimination of dust problems and the safety considerations/control equipment associated therewith; (2) a substantial reduction in chemical (e.g. fire retardant) use; and (3) a corresponding reduction in material costs due to decreased chemical use. In addition to the foregoing benefits, the final insulation products manufactured in accordance with the invention readily meet all applicable government requirements, and have a lower average bulk density compared with materials produced using powdered fire retardants.
The term “bulk density” as used herein is defined to encompass the weight (traditionally in lbs.ft 3 ) of the final settled insulation product. A final product with a low bulk density is desired because it imparts less weight to the building structure in which it is used. In addition, a final product with low bulk density is more free-flowing, easier to handle, and more readily installed. In addition, since cellulose insulation is typically sold by coverage (i.e., volume), an insulation material with a lower bulk density enables a manufacturer to sell less weight without diminishing performance. Furthermore, the fiber materials in the final or completed product have a higher degree of rigidity which results in less settling of the product when used in a building structure compared with insulation products that are conventionally-prepared using fire retardants in powdered (dry) form. Minimal settling of the insulation product is beneficial because it enables less of the product to be used, thereby providing significant cost savings. The completed insulation product is also characterized by a substantial absence of detached fibrous residue which, if present, can increase its density. Accordingly, the present invention represents an advance in the art of cellulose insulation manufacture, and provides many economic, safety, quality-control, and other benefits compared with powder-based systems as further discussed below.
The invention provides methods for producing a low-dust cellulose fiber material useful in producing insulation and other such products. In embodiments of a method of the invention, a liquid comprising a solvent and at least one fire-retarding material soluble in the solvent, is applied to a cellulose source material. The liquid is allowed to permeate into the cellulose source material. The liquid permeated material is dried to remove the solvent while the fire-retardant material remains in the cellulose source material. The dried cellulose source material is then reduced in size to produce a fire-retardant cellulose fiber material. The fire-retardant cellulose fiber material is then de-dusted to produce a low-dust fire-retardant cellulose fiber material that has functionally equivalent fire-retardant properties as the fire-retardant cellulose fiber material before de-dusting.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention are described below with reference to the following accompanying drawings, which are for illustrative purposes only. Throughout the following views, the reference numerals will be used in the drawings, and the same reference numerals will be used throughout the several views and in the description to indicate same or like parts.
FIG. 1 is a schematic illustration of an embodiment of a conventional processing system for producing a fire-resistant cellulose insulation material through the application of liquid fire-retardant compositions to cellulose materials.
FIG. 2 is a schematic illustration of process steps, materials, and procedures following the process illustrated in FIG. 1 , associated with the production of a de-dusted, fire-resistant cellulose insulation material according to an embodiment of the present disclosure.
FIG. 3 illustrates an embodiment of a de-dusting apparatus composed of a screen unit.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The following description with reference to the drawings provides illustrative examples of de-dusted fire-resistant cellulose insulation material and methods according to embodiments of the invention. Such description is for illustrative purposes only and not for purposes of limiting the same.
The present invention provides a unique and highly efficient method for producing a de-dusted, fire-resistant cellulose (e.g., paper-based) insulation product. The present methods achieve the above-described benefits, at least in part, through the use of fire retardant compositions that are exclusively liquid with a total absence of a powder-type fire retardant, for example, conventional powder-type fire retardants such as those described in U.S. Pat. No. 4,168,175 and U.S. Pat. No. 4,595,414 (Shutt). As such, the present methods avoid the use of powdered (dry) fire retardant compositions.
To manufacture a fire-resistant cellulose insulation product utilizing an all-liquid system, embodiments of the present invention are characterized by a combination of unique processing steps which enable the correct amount of liquid fire retardant compositions to be diffused within the selected cellulose materials, permit complete drying of the cellulose materials while producing minimal amounts of fine fibrous residue and removal of a majority to substantially all dust from the dried and size-reduced fire-resistant cellulose insulation product.
Processes for applying liquid fire-retardant compositions to cellulose materials are known in the art. FIG. 1 provides a schematic illustration of an embodiment of a processing system 10 with process steps and equipment for producing a fire-resistant cellulose insulation product through the application of a liquid fire-retardant composition to cellulose material as described in U.S. Pat. No. 5,534,301, the disclosure of which is incorporated in its entirety herein.
As illustrated, a supply of cellulose material 14 is initially provided. The cellulose material 14 will basically involve vegetable fiber materials, wood fiber compositions, or any other cellulosic substrates which are known in the art for producing insulation materials. Preferably, the supply of cellulose material 14 will consist of virgin (unused) or recycled (used) paper, with the term “paper” encompassing commercial products derived from wood or other plant materials ranging from newspaper to cardboard, fiberboard, and paperboard. However, the present invention shall not be limited to any particular paper or cellulose compositions, with a variety of different materials being suitable for use in the system 10 . In a preferred embodiment, paper is used as the supply of cellulose material. The term “paper” as used herein shall encompass a wide variety of vegetable or wood-based fiber materials ranging from conventional paper products to cardboard, fiberboard, and the like. Furthermore, the selected paper materials can include virgin (unused) products or, in a preferred embodiment, recycled paper. An exemplary and preferred product suitable for processing in accordance with the invention involves recycled (used) newspaper (optimally “grade 8” newspaper).
The selected supply of cellulose material 14 (e.g. recycled newspaper, Kraft paper, etc.) is then loaded onto a platform such as a feed table 18 where the material 14 is sorted and separated from non-cellulose materials and other materials. The cellulose material 14 can then be routed via a conveyer belt system 22 , for example, into a shredding and/or grinding apparatus 26 to physically reduce the size of the material to a desired level and produce a plurality of individual pieces of paper 30 which, in a preferred embodiment, have an average width and length of about 2-6 inches (about 5-15 cm). While these numerical values are preferred for use in the claimed process, the present invention shall not be limited to the foregoing numerical parameters which are provided solely as an example. The precise paper size to be used at this stage of the process can be determined in accordance with preliminary pilot studies on the paper material being processed and treated.
The individual pieces of paper 30 are then transferred from the shredding apparatus 26 into an air transport system 34 as known and used in the art for material transfer, which uses an air flow to move the pieces of paper to the next stage of the system 10 , i.e., a spraying system 42 . A conventional spraying apparatus such as a standard spray booth 50 can be utilized. The spraying system is designed to deliver at least one liquid fire retardant composition 46 to the pieces of paper 30 , and can include one or more spraying nozzles 54 connected to a tank 58 containing the selected liquid fire retardant composition. Within the spraying system 42 (e.g., spray booth 50 ), the pieces of paper 30 are converted into a fire retardant-soaked paper product 32 , which comprises the initial pieces of paper 30 soaked with the liquid fire retardant composition 46 .
To ensure proper and complete diffusion of the liquid fire retardant composition within the paper, the liquid fire retardant composition 46 is optimally delivered to the paper materials 30 in the form of a fine mist comprising a plurality of droplets each having a diameter of about 40-200 microns. Using this approach, the selected fire retardant composition 46 can adequately and completely diffuse into the fibrous matrix of the paper 30 . Spraying of the liquid fire retardant composition 46 in a fine mist provides many benefits including but not limited to (1) a reduction in the amount of liquid fire retardant composition 46 that is needed; (2) greater dispersion of the composition 46 within the internal fibrous matrix of the paper 30 ; and (3) a lack of chemical fire retardant dust in the final product as discussed below.
Any liquid-soluble fire retardant chemical can be used which is capable of imparting fire resistance to the selected cellulose materials. For example, a variety of fire retardant compounds which may be used in solution form as the liquid fire retardant composition 46 are listed in U.S. Pat. No. 4,595,414 and U.S. Pat. No. 4,168,175 (Shutt), the disclosure of which is incorporated herein by reference. For example, aqueous solutions of the following compounds may be used as the liquid fire retardant composition: ammonium sulfate, monoammonium phosphate, diammonium phosphate, boric acid, sodium tetraborate, ferrous sulfate, zinc sulfate, and mixtures thereof. Examples of fire retardant materials/mixtures include ammonium sulfate (alone), a mixture of about 93.7% wt. ammonium sulfate and about 6.3% wt. boric acid, and a mixture of about 40% wt. monoammonium phosphate and about 60% wt diammonium phosphate, which are ultimately combined with water to produce aqueous solutions.
Solutions of many different fire retardant chemicals can be used in the described process, with the present invention not being limited to any particular agents or combinations thereof. The selected fire retardant composition 46 will typically be formulated as an aqueous solution, preferably having about 35-42% by weight total of one or more fire retardant compounds dissolved therein. Application of the liquid fire retardant composition 46 will typically produce a fire retardant-soaked paper product 32 which (prior to drying) will contain about 12.5-30% by weight fire retardant composition 46 . Upon drying, the dried insulation product will typically contain about 5-12% by weight of the selected fire retardant compound(s) which were applied in solution form. The compositions 46 can further include one or more optional additives such as a wetting agent.
Additionally, fire-retardants in which the solvent is not water (e.g., an organic solvent), are considered within the scope of this invention. Of course, non-aqueous solvents will require suitable equipment and safety measures.
Referring to FIG. 1 , the fire retardant-soaked paper product 32 is then transferred into a drying chamber 88 along with a stream of heated air (designated by arrows 94 ). However, between the application of a selected liquid fire retardant composition to the paper and passage of the fire retardant-soaked paper product into the drying chamber 88 , a given amount of “dwell” (delay) time period is allowed to lapse. A sufficient amount of dwell time ensures complete diffusion of the liquid fire retardant composition 46 into the interior regions of the pieces of paper 30 . In a preferred embodiment, a dwell time period of about 45-120 seconds will be allowed to lapse after application of the liquid fire retardant composition 46 to the paper materials, with the exact time period depending on the type of paper being employed and other experimentally-determined factors.
The imposition of dwell time at this stage in the system can be accomplished in many ways, with the present invention not being limited to any particular method. For example, prior to passage of the fire retardant-soaked paper product 32 into the drying chamber 88 , the paper product 32 can be allowed to reside in one or more stationary hoppers 80 or containment vessels for a selected amount of time. Likewise, after production of the fire retardant-soaked paper product 32 , the paper product can be conveyed to subsequent parts of the processing system 10 using conventional transfer systems (e.g., feed screws, conveyor belts, and the like) which are operated at a controlled rate of speed to impart a delay in moving the paper product 32 through the system 10 . This procedure may be employed with or without the use of stationary hoppers 80 to provide a sufficient degree of dwell time.
Prior to or simultaneously with the entry of paper product 32 into the drying chamber 88 , a stream of heated air (designated by arrows 94 ) is passed into and through the drying chamber 88 . The stream of heated air 94 is designed to simultaneously move and dry the paper product 32 within the chamber 88 . In a preferred embodiment, the drying chamber 88 is circular in cross-section and tubular in design with a longitudinal axis X 1 therethrough.
To achieve optimum drying of the fire retardant-soaked paper product 32 within the drying chamber 88 , it is preferred that the stream of heated air 94 is introduced (delivered) into the drying chamber in an angled and non-parallel orientation relative to the longitudinal axis X 1 of the drying chamber 88 , designed as A 1 in FIG. 1 . The angle A 1 of air introduction will preferably be about 90° relative to the longitudinal axis X 1 of the drying chamber 88 so that the stream of heated air 94 enters the drying chamber 88 in a direction which is perpendicular to the longitudinal axis X 1 of the chamber 88 . However, depending on the particular configuration of the system 10 , the angle A 1 of air introduction relative to the longitudinal axis X 1 of the drying chamber 88 can range from about 60°-90°, with about 90° being preferred. It is also preferred that the stream of heated air 94 be introduced in a manner wherein the stream is laterally offset from (e.g. to the side of) the longitudinal axis X 1 of the drying chamber 88 . As a result, the stream of heated air 94 entering the drying chamber 88 will travel in a substantially helical pathway around and along the circular interior surface of the chamber wall which slows the movement of paper product 32 passing through the chamber 88 . In a preferred embodiment, the stream of heated air 94 is introduced into the chamber at a flow rate of about 2500-3500 ft./min. (which may be varied as necessary in accordance with preliminary pilot studies on the materials being processed).
The fire retardant-soaked paper product 32 is passed into and through the drying chamber 88 in combination with the stream of heated air 94 after completion of the dwell time period. The stream of heated air 94 is designed to simultaneously move the paper product 32 through the drying chamber 88 to achieve complete drying of the paper product 32 within the chamber. However, to properly implement the all-liquid fire retardant system of the present invention, an additional amount of dwell time can be imparted to the paper product 32 within the drying chamber 88 to ensure that the paper product 32 is completely dried. If the paper product 32 is allowed to flow through the drying chamber 88 with the stream of heated air 94 in an uninterrupted manner, the paper product 32 may not be completely dry upon leaving the chamber 88 . Although introduction of the heated air 94 in a helical flow path causes the paper product 32 to pass through the chamber 88 at a slower rate (compared with a linear flow path), additional dwell time may be needed to ensure complete drying.
To completely dry the fire retardant-soaked paper product 32 , the process involves temporarily interrupting passage of the fire retardant-soaked paper product and heated air 94 through the drying chamber 88 periodically (e.g., at least once and preferably multiple times) during movement of these components through the drying chamber 88 . This step slows the flow of the paper product 32 and heated air 94 through the drying chamber 88 , which enables greater contact between the heated air 94 and paper product 32 . Since interruption of these components is temporary and periodic (e.g., at selected intervals), once the paper product 32 and air 94 begin moving again after being interrupted, the stream of air 94 accelerates faster than the paper product 32 . This occurs because the air 94 is lighter and less dense than the paper product 32 . As a result, the stream of heated air 94 flows over the surface of the slower-moving paper product 32 , causing more intimate contact and increased drying of the paper product. In this regard, the more interruptions of the foregoing paper product 32 and the air 94 , the greater the drying capacity of the system 10 . Without temporarily and periodically interrupting (e.g. slowing) the foregoing components as they move through the drying chamber 88 , an inadequately-dried material would be generated. As a result of the above-described process, a dried fire-resistant cellulose insulation product is generated within the drying chamber 88 .
There are numerous ways to temporarily and periodically interrupt the flow path of the fire retardant-soaked paper product 32 and the stream of heated air 94 as they pass through the drying chamber 88 . Accordingly, the present invention shall not be limited to any particular method or apparatus for this purpose. In a preferred embodiment, temporary interruption of the paper product 32 and air 94 as they flow through the drying chamber 88 can be accomplished through the use of a chamber which includes one or more stationary or movable baffle members 170 therein. In a preferred embodiment, the drying chamber 88 includes moveable (e.g. rotatable) baffle members that are continuously moved within the drying chamber during passage of the heated air and paper product therethrough. As a result, the paper product 32 passing through the drying chamber 88 comes in contact with (e.g. physically engages) at least one and preferably multiple baffle members during movement of the baffle members within the chamber. Engagement of the paper product 32 with the baffle members temporarily interrupts the transportation and flow of the paper product 32 through the drying chamber. The same situation occurs regarding the stream of heated air 94 as it moves through the drying chamber 88 . As a result, passage of the paper product 32 through the drying chamber 88 is substantially slowed (compared with a chamber which lacks any baffle members therein). While a delay also occurs regarding the stream of air 94 as it encounters the baffle members and moves through the chamber 88 , this delay is less compared with the paper product 32 due to the minimal weight and density of air 94 . This process in which the paper product 32 experiences a greater degree of delay or “dwell” (delay) time within the chamber 88 compared with the stream of heated air 94 enables a more continuous and sustained level of air flow over and in contact with the paper product 32 . As a result, the paper product 32 is completely dried so that an adequately dried fire-resistant cellulose insulation product can be produced within the drying chamber.
After passage of the paper product 32 through the drying chamber 88 , it exits the chamber 88 via outlet port 126 ( FIG. 1 ). Within the chamber 88 , drying of the paper product 32 produces a dried fire-resistant cellulose insulation product 250 which is collected from the chamber 88 and further processed as desired to create a final product with additional size reduction and specific size characteristics. Size reduction can be accomplished, for example, using one or more hammermill units 254 , 284 , or other comparable systems known in the art for this purpose, to produce a size-reduced insulation product 280 , e.g., in which each piece of paper in the product 280 has a length and width of about 0.25-1 inch (about 0.6-2.5 cm), and ‘completed’ insulation product 300 having the desired size of the product, e.g., in which each piece of paper in the product 300 has a length and width of about 0.01-0.2 inch (about 0.025-0.5 cm).
The size reduction processing to produce the dried fire-resistant cellulose insulation product 300 typically produces a substantial quantity of dust (i.e., material with very small particle size), which contains residues and chemicals that can be easily inhaled. Although the dust that is generated is generally about 10% less than the amount produced in powder-type fire-retardant systems, the amount of dust associated with the dried product 300 can pose significant problems such as lack of visibility and personal nuisance due to a high amount of air-borne dust particles when the material is applied as an insulation, particularly for people with sinus, asthma and other respiratory problems. The inventor has discovered that, unlike known processes in this art, the current material can be processed to eliminate a major amount (i.e., at least 50% by volume or more) to substantially all (i.e., about 90-100% by volume) of the dust.
Referring now to FIGS. 2-3 , according to the invention, after processing to reduce the size of the dried paper material, the completed, size reduced insulation product 300 is subjected to a dust removal (de-dusting) process 310 . The de-dusting can be performed by any suitable process, for example, by screening, air classification, or other known separation techniques. Preferably, the de-dusting is performed by a screening technique or screening in combination with another separation technique.
In embodiments of a de-dusting process 310 , the dried insulation product 300 can be conveyed, for example by means of a conduit or chute 320 to a screening apparatus 330 . The screening apparatus 330 is composed of one or more screen (sieve) units 340 a,b and structured to process a desired quantity of the dried insulation product 300 .
Preferably, the screening apparatus 330 is operable to maintain movement of the dried insulation product 300 on and across the mesh screen 350 of the screen unit 340 a,b to increase the percentage of dust that is removed. The screening apparatus can be structured and operable to provide such movement of the material on the screen, for example, by rotating, vibrating, or other motion mechanism (arrow ‘A’) as shown in FIG. 3 , or by use of an air supply to apply pulsed air or a gentle air stream underneath the material on the screen (arrow “B”) to sweep, brush or vibrate the material 300 .
The contact parts of the screen unit 340 , including the mesh screen 350 , are composed of a material that is chemically compatible with the dried insulation product 300 , for example, a stainless steel or nylon. The screen 350 has a mesh size that is suitable for effectively separating a sufficient amount of dust from the dried insulation product 300 , preferably to produce a substantially dust-free material by removing at least about 50% by volume of the dust content of the dried insulation product 300 , more preferably at least about 70-100% by volume of the dust, and more preferably about 90-100% by volume of the dust. The mesh of the screen can range from about 200 mesh to about 10 mesh, and is preferably about 40 mesh to about 14 mesh, more preferably about 30 mesh to about 20 mesh.
The screen units 340 are structured to provide a high throughput rate and process a high capacity or volume of dried insulation product 300 in a suitable time period, preferably at about 1000 lbs/hour per unit, and more preferably at about 2000 lbs/hour per unit. Depending on the volume and the character of the material 300 being processed, one or more screen units 340 can be used. For example, as depicted in FIG. 2 , two or more screen units 340 a,b can be set up in a side-by-side arrangement, or in a spoke-type arrangement, etc., with each screen unit connected to a conduit 320 a,b for transfer of the dried insulation product 300 into the screen unit. In addition, to process a high volume of dried insulation product 300 , a wide diameter screen can be used, for example, having a diameter ranging from about 30″ (76 cm) to about 60″ (152 cm) or greater. Screen units 340 can used singly or can be stacked.
An example of a suitable screening apparatus 330 for use in the de-dusting process 310 of the invention is a gyratory (vibratory), high capacity, production separator or sieve (e.g., Models VS0048 (single deck) and VS0060 (double deck)), available commercially from VORTI-SIV®, a division of Industries, Inc., Salem, Ohio U.S.A.
As depicted in FIG. 3 , the waste dust material 360 will pass through the open mesh screening 350 of the screening unit and into a collection unit 370 (e.g., a bin, etc.) for disposal.
In general, dust material is finely divided solid particles that can be readily suspended in the air and/or remain suspended in the air for a time after the bulk material has substantially settled. Typically, in a cellulose insulation product that has been processed using a dry powder fire-retardant chemical, the reduced size dry product will contain about 14-26% by weight dust based on the total weight of the material, composed of about 10-20% by weight of cellulose-based (e.g., paper) dust and about 4-6% by weight of fire-retardant dry chemical dust. Consequently, de-dusting of a reduced-size cellulose insulation product processed using a dry powder fire-retardant chemical removes a significant amount of fire-retardant chemical material from the product resulting in a product that does not meet federal or industry standards for a fire-retardant material.
By comparison, the inventor has found that for a cellulose insulation product that has been processed using a liquid fire-retardant chemical, the reduced-size dry product will typically contain about 8-15% by weight dust composed of about 7.5-15% by weight cellulose-based (e.g., paper) dust with about 0.5-1.5% by weight of fire-retardant chemical adhered to the dust, and de-dusting according to the invention can remove a substantial amount of dust (up to 100% of the dust) from the reduced-size dry product with substantially no loss of fire-retardant properties.
Following dust removal, the de-dusted, fire retardant dried insulation product 380 , can then be conveyed from the screening apparatus 330 , for example, through a conduit or chute 390 to a bale press or baler 400 or to a bagging apparatus 410 , as known and used in the art, and packaged for transport and future use. In use, the de-dusted, fire retardant dried insulation product 380 can be placed into a hopper and mechanically fluffed up, and then “blown” in place directly into an attic, into stud spaces in an existing wall, and other applications.
Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement which is calculated to achieve the same purpose may be substituted for the specific embodiments shown. This application is intended to cover any adaptations or variations that operate according to the principles of the invention as described. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof. The disclosures of patents, references and publications cited in the application are incorporated by reference herein. | A method of producing a low-dust, fire retardant cellulose fiber material useful in producing insulation and other such products is provided. A liquid, comprising a solvent and at least one fire-retarding material soluble in that solvent, is applied to a cellulose source material, and the liquid is allowed to permeate into the cellulose source material. The liquid permeated material is dried to remove the solvent while the fire-retardant material remains in the cellulose source material. The dried fire-retardant cellulose source material is reduced in size and then de-dusted to produce a low to no dust, fire-retardant cellulose fiber material that has functionally equivalent fire-retardant properties as the dried fire-retardant cellulose source material before de-dusting. | 3 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0000]
U.S. Utility patent application Ser. No. 10/820,930; and
U.S. Utility Provisional Patent Application 60/517,130,
to which this patent application claims priority under 35 USC 119(e)
BACKGROUND
[0004] 1. Field of the Invention
[0005] The present invention relates to a light emitting diode (LED) illumination device and method and more specifically to a light emitting diode, integrated with electronic circuitry that enables both an illumination function as well as a decorative function that can be varied by the user.
[0006] 2. Description of Related Art
[0007] Currently lighting applications are dominated by incandescent lighting products. Because they use hot filaments, these products produce considerable heat, which is wasted, in addition to visible light that is desired. Halogen based lighting enables filaments to operate at a higher temperature without premature failure, but again considerable non-visible infrared light is emitted that must be disposed of. This is conventionally done by using a dichroic reflector shade that preferentially passes the infrared as well as a portion of the visible light. The nature of this dichroic reflector is such that it passes several different visible colors as well as the infrared radiation, giving a somewhat pleasing appearance. This has lead to numerous applications for the halogen lights in which the entire light is used for decorative purposes. These lights consume substantial current and dissipate considerable unwanted heat. These bulbs are designed to operate at a variety of voltages between 12 Volts to as high 115 Volts or greater.
[0008] Light emitting diodes have operating advantages compared to ordinary incandescent as well as halogen lights. LEDs can emit in a narrow range of wavelengths so that their entire radiant energy is comprised within a predetermined range of wavelengths, eliminating, to a large degree, wasted energy. By combining light colors white can be created. Because such LEDs can now emit in the ultraviolet, the emitted radiation can also be used to excite a phosphor to create white light and other hues.
[0009] LEDs have an extremely long life compared to incandescent and halogen bulbs. Whereas incandescent and halogen bulbs may have a life expectancy of 2000 hours before the filament fails, LEDs may last as long as 100,000 hours, and 5,000 hours is fairly typical. Moreover, unlike incandescent and halogen bulbs, LEDs are not shock-sensitive and can withstand large forces without failure, while the hot filament of an incandescent or halogen bulb is prone to rupture.
[0010] Halogen bulbs, incandescent bulbs, and LEDs all require a fixed operating voltage and current for optimal performance. Too high an operating voltage causes premature failure, while too low an operating voltage or current reduces light output. Also, the color of incandescent and halogen lights shifts toward the red end of the visible spectrum as current and voltage are reduced. This is in contrast to LEDs, in which only the intensity of the light is reduced. Furthermore, as the voltage to an incandescent and halogen light is reduced, its temperature drops, and so its internal resistance decreases, leading to higher current consumption, but without commensurate light output. In cases where batteries are used as the source of energy, they can be drained without producing visible light.
[0011] Incandescent and halogen bulbs require a substantial volume of space to contain the vacuum required to prevent air from destroying the filament and to keep the glass or silica envelope from overheating and to insulate nearby objects from the damaging heat. In contrast, LEDs, being solid state devices, require much less space and generate much less heat. If the volume of an incandescent or halogen bulb is allocated to a solid state LED light, considerably more functions can be incorporated into the lighting product.
[0012] Unlike incandescent and halogen lights, LEDs ordinarily produce light in a narrow, well defined beam. While this is desirable for many applications, the broad area illumination afforded by incandescent and halogen lights is also often preferred. This is not easily accomplished using LEDs. The light produced by incandescent and halogen lights that is not directed towards the target performs a useful function by providing ancillary illumination and a decorative function. Halogen lights with their dichroic reflectors do this unintentionally, but ordinary incandescent lights employ external shades, not part of the light bulb, in a variety of artistic designs to make use of this otherwise misdirected light.
SUMMARY OF THE INVENTION
[0013] The present invention overcomes the limitations of halogen or incandescent light sources, and combines their desirable properties with the advantages afforded by LEDs into a unique system and product intended for general illumination purposes.
[0014] An embodiment of the present invention may therefore comprise an LED lamp that is capable of replacing standard incandescent and halogen bulbs for a wide variety of purposes. The functionality of this lighting system will go well beyond what is available in ordinary incandescent and halogen lights. Note that standard bulbs frequently are used in fixtures which provide two functions: direct lighting and decorative lighting. The decorative lighting in particular is often associated with a shade, which may alter various properties of some or all the illumination, some of which may be superfluous to the direct illumination function.
[0015] This embodiment will contain an electrical connector or base the same as or equivalent to the standard bulb base, a printed circuit board (or other circuit substrate or module) electrically connected to the base, a driving circuit that is mounted on or embodied by the printed circuit board, and one or more LEDs of one or more colors attached to the printed circuit board. The driving circuit comprises a solid state circuit that regulates the voltage and current available from the source and regulates the output to the constant value required for the LEDs. The available source voltage be either above or below that required by the LEDs.
[0016] An additional embodiment to the present invention may also comprise an LED lamp that replaces incandescent and halogen lamps as well as their decorative shades by including LEDs on both sides of the printed circuit (PC) board, where the LEDs are on the opposite side of that intended for direct illumination and where they provide the decorative function. These LEDs may provide a decorative function by illuminating the built-in envelope or shade around the lamp.
[0017] An additional embodiment to the present invention may include additional circuitry occupying the volume available. This circuitry may include the following: circuitry to allow remote control of lighting functions via an infrared or wireless device; circuitry to change the color of either or both of the (decorative) shade illumination and the direct illumination LEDs; circuitry that causes a time variant color and or intensity to the (decorative) shade illumination and/or the direct illumination; circuitry that allows the external switching via mechanical action of color, pattern or intensity on either the shade or direct illumination; circuitry that enables the switching of the various functions of color, intensity, pattern by interrupting the power to the circuit within a predetermined time interval.
[0018] An additional embodiment to the present invention may include mechanical actuators that alter the pattern and color of light to the shade for the purpose of decorative illumination. This may include a mechanical method such as a shadow screen, multi-faceted mirror or other reflective or diffractive optical component or components either fixed within the envelope of the lighting unit, or provided with a means of moving the internal components to vary the pattern and or color of the resulting light for decorative or functional purposes.
[0019] An additional embodiment of the present invention may comprise the method or methods for accomplishing the above-mentioned attributes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 illustrates an example of the current state-of-the-art halogen illumination device referred to commonly as an MR-16.
[0021] FIG. 2 illustrates an embodiment of the present invention that can retrofit the halogen illumination device and contains LEDs for illumination on one side and LEDs for direct illumination on the other. Circuitry to enable regulation and other features is also shown.
[0022] FIG. 3 illustrates an embodiment of the present invention in which high intensity LEDs are placed on both sides to produce shade illumination and direct illumination. A switch and circuitry for changing the attributes of the lighting is also shown.
[0023] FIG. 4 illustrates another embodiment of the present invention in which a movable, multifaceted mirror is included on the shade side of the illumination unit to provide a variable pattern on the shade.
[0024] FIG. 5 illustrates another embodiment of the present invention in which an internal fixture containing apertures is included to pattern illumination to the shade.
[0025] FIG. 6 illustrates a means for producing a series/parallel circuit comprised of individual LED semiconductor chips on a circuit board that results in a high density lighting array.
[0026] FIG. 7 shows and embodiment of the high density LED array in which it is coupled with an integrated lens array that is movable to produce variable directional lighting.
[0027] FIG. 8 is a constant current implementation of a compact dc/dc boost converter with a feature that enables current regulation of the LEDs based on the thermal environment.
[0028] FIG. 9 is a compact constant current buck/boost circuit in which several methods that enable current regulation based on the thermal environment are illustrated.
DETAILED DESCRIPTION OF THE INVENTION
[0029] While this invention is susceptible to embodiment in many different forms, there are shown in the drawings, and will be described herein in detail, specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not to be limited to the specific embodiments described.
[0030] FIG. 1 illustrates an incandescent halogen type bulb commonly available. The features of this bulb have been derived from the operating characteristics implicit in the operation of these type illumination devices: they operate at high temperatures; they require an evacuated envelope separated from the hot filament; they emit large quantities of infrared radiation experienced by the user as heat; and they consume large quantities of electrical power. Nonetheless these devices are in common usage and fixtures and appliances have been constructed to accommodate the form, fit, and function of these bulbs. This particular unit is a model MR-16.
[0031] FIG. 1 illustrates the incandescent halogen bulb and its essential components. These are a connector 101 that attaches to a standard source of electrical power which has a mating adapter; an evacuated transparent capsule 102 containing the hot filament 105 ; an envelope 103 that acts as a shade and filter to allow infrared radiation to pass, while reflecting a portion of the desirable visible light to the objects below; a transparent front cover 104 that allows the radiation to pass, while protecting the evacuated capsule 102 from breakage.
[0032] In contrast to incandescent lights, LEDs consume less power, emit in a narrow beam, emit less heat, and can be formulated in a wide variety of colors both inside and outside the spectrum visible to humans. Because of these implicit differences, the use of LEDs creates opportunities to add operation features to light bulbs, which heretofore were considered simple illumination devices. It is the object of this disclosure to enumerate unique features that will improve the usefulness of the lighting devices based on LEDs.
[0033] FIG. 2 illustrates the first embodiment of the current invention. This illuminating device is intended to have the same form fit and function as the incandescent illumination device of FIG. 1 and as such has a similar electrical connector 201 and similarly shaped transparent or translucent envelope 202 . The envelope 202 will act to scatter light emitted from inside the envelope and be visible from the outside. As such, the envelope 202 can serve as a screen onto which are projected and displayed images, colors or other decorative or information-containing light either visible to humans or at shorter or longer wavelengths. The content of this information is formulated by circuitry contained on one or more circuit boards 206 contained within the envelope of the bulb 202 . This circuit 206 in its simplest form controls other illumination devices such as the LEDs 207 also located on the back of the circuit board 204 . Another circuit 205 can be used to control high power LEDs 209 in an array 208 located on the opposite side for direct illumination of objects outside the envelope of the lighting device. However, this circuit or circuits may enable several useful features. These are:
1. A timer to adjust the color and illumination level according to some preset or user-adjustable schedule. 2. A photocell to turn on or off the light depending on the ambient light level and or a proximity sensor. 3. A signaling function that communicates with other lights 4. A switch that is user accessible that allows a switching of illumination characteristics such intensity, color, continuous or flashing illumination modes.
[0038] Also located on circuit board 204 is a power conditioning circuit 205 that regulates power to the high intensity LEDs 208 located on the underside of the board. This circuit adapts and controls the power available via the connector 201 and conducted to the board via wires 203 . The circuit 205 may contain storage features including a battery to enable the lighting device to act as an emergency light source in the event of a power failure. The circuit may rectify ac power to dc to suit the desired current and voltage required by the series and/or parallel array of LEDs and provide power to other on-board circuitry.
[0039] In this embodiment, the LEDs 207 on the backside of the PC board 204 can serve the function of communication and or decoration. For decorative purposes, the shade 202 will be made of a colored or white transparent or preferably translucent material such as plastic or glass which is textured so as to scatter light. In this manner light from the LEDs 207 impinge on this surface and are made more visible to the user, and can serve the function of decoration. The shade 202 may also contain penetrations 210 to allow heat to exit the LED enclosure.
[0040] FIG. 3 illustrates a similar incandescent replacement product. This product also contains an electrical connector 301 , a shaped translucent or transparent envelope 302 with holes 310 to remove heat, one or more printed circuit boards 304 within the enclosure, means such as wires 303 to conduct electrical power to these board(s), The product now has high intensity illumination LEDs 307 on the top surface and other high intensity LEDs 309 in an array 308 on the bottom surface. Unlike the product of FIG. 2 which had small LEDs with a narrow exit beam and low intensity, these high intensity LEDs 309 and 307 have a higher light output generally greater than 10 lumens and the exit angle of the light may range from a narrow angle to a very broad beam as desired. To control these LEDs additional circuitry may be required as shown in the figure. In addition to the power transforming circuit 305 , and the control circuits 306 , additional power handling circuits 311 may be necessary. These high power LEDs may have one or more colored light outputs other than white, and have different orientations other than vertical to provide decorative illumination above the lighting product. A switch 311 that is accessible by the user can be used to control characteristics of operation of the lighting product.
[0041] FIG. 4 illustrates another embodiment of the product. Unlike the previous examples in which modification of the color, intensity and pattern took place by electrically controlling the electrical power to individual devices of one or more orientations and color, this product contains a mechanical method for varying the intensity, and pattern with time. This is accomplished for example using a multi-faceted mirror 420 , operated by a miniature electric motor 421 that changes the orientation and position of the mirror. In this way light is reflected or diffracted to form a pattern of shapes and color on the translucent or transparent envelope 402 .
[0042] FIG. 5 illustrates another embodiment in which is added the feature of a patterned mask 520 that casts a shadow or other optical means a predetermined pattern by blocking or otherwise modifying the pattern of light emanating from the internal LEDs 507 located on the back side of the circuit board 504 . Other features from other embodiments discussed already may also be incorporated.
[0043] It may be appreciated from these descriptions that the LEDs used in these embodiments, though small, occupy considerable space that limits the overall light output of the product. This is due to the need to provide electrical connections to each of the semiconductor light emitting chips that are housed in large packages that provide both electrical connections and a means for removing heat and permit the exiting of useful light. The packages also often contain a lens or mirror for shaping and directing this light. While these packages allow some freedom of use, they also limit the density and eliminate the means to provide the integration of the functions of heat dissipation, light direction and electrical connection by independent means. Many of these functions could be accommodated within a printed circuit board of appropriate design for a group of devices at the same time and within the circuit as it is formed.
[0044] One means of improving the light density of the overall product is to incorporate the light emitting dies onto a suitable patterned circuit board that contains the external circuitry needed to power and connect the LED devices without the excess baggage of a package. FIG. 6 illustrates such an arrangement. The embodiment consists of a printed circuit board comprised of at least a middle portion 601 that may be the usual fiberglass core or one that contains metals, ceramics or other materials to enhance thermal conductivity, a top metal clad layer 603 and a bottom cladding layer 602 . It should be well understood that these top and bottom layers can easily be patterned by such processes as etching. A light emitting assembly can be attached to the patterned surface of cladding 603 by cementing with a thermally and electrically conducting compound or by welding or some other method. Then the cladding 603 may act as either or both a thermal and electrical conducting pathway. The light emitting assembly consists of a metal base 604 to which is bonded a semiconductor light emitting chip 605 . This light emitting chip contains a pn junction that emits light and conducting top and bottom surface layers for electrical and thermal contact. A conducting wire or tab connects the top conducting member of the junction to the opposite conducting pad on the next assembly, thus building up a circuit that is in series. Using a different connection scheme, but the same general method, a parallel connection can be assembled. By doing this, a relatively dense build-up of light emitting chips can be assembled using the thermal and electrical transfer characteristics of the printed circuit board. Furthermore, heat sinking, cooling or other components can be attached to the board, improving performance, for example on the back side 602 of the printed circuit board. Although not shown, it should be understood that this connection method can be extended in the two dimensions of the plane of the board.
[0045] Such chips as illustrated in FIG. 6 will emit light in all directions. Such a distribution of light may not be desired for any lighting applications. Therefore, a matching array of lens that is positioned over the light emitting chips would be desirable. This separation of the top lens array from the LEDs is desirable as it allows the lens array to be positioned independently, allowing the light directed by the lens to be moved and/or focused by moving the lens array in the three dimensions. The movement can be controlled via a variety of methods such as stepper motors or piezoelectric activated motion controllers whose support electronics is also contained on the printed circuit board. The array of lenses can be molded from a transparent clear or colored material with a variety of spherical or hemi-spherical shapes.
[0046] FIG. 7 illustrates such an arrangement. The PC board 701 containing patterned metal traces 703 has located on its surface light emitting portions consisting of semiconductor light emitting devices 705 that are mounted on bases 704 . These areas are bonded together with electrically conducting wires or strips to form a series/parallel circuit. Positioned over the top of these light emitting regions is a lens array 710 into which have been formed by a method such molding, a matching series of optical elements. Three such elements of two different shapes labeled 711 and 712 are shown. This lens array 710 is spaced apart from the semiconductor array and mounted in such a manner that it can be externally manipulated in one or more of the three dimensions as shown by the opposing pairs of arrows. Hence, by moving the lens array, the light emitted from the matching LED array can be directed and focused as required, in essence steering the light beam. This can be controlled by onboard electronics, and via remote control or such other means as required such as proximity sensors, timers and the like.
[0047] These lighting products require a source of alternating (ac) or direct current (dc). Although LEDs utilize direct current, it is possible to use the LEDs to rectify ac power provided the number of LEDs is chosen to match the ac voltage. It is well understood how to transform ac power to dc via a variety of well-established methods. The use of dc power as supplied by batteries however, presents some problems because as the battery voltage declines under load, the current drawn by the LEDs rapidly declines, owing to the extremely non-linear current-voltage characteristic inherent in a diode. Since the light output of a LED is directly proportional to current, this means the light output rapidly declines. On the other hand, if battery voltage exceeds a predetermined level, heating of the semiconductor junction that comprises the LED is excessive and can destroy the device. Moreover, excess heat in the LED junction causes a condition called thermal runaway, in which the heat raises the current drawn at a given voltage, leading to further heating, which in turn leads to greater current draw and quickly destroys the device. This is especially a problem with high power LEDs and requires careful thermal management.
[0048] In order to help avoid this problem it is useful to fix the current through the LEDs rather than the voltage. Using a battery as the source of current however presents a problem because of the differing voltage and current behavior of the battery power source and the LED load. Therefore, a circuit is desired to regulate and fix the current independent of the voltage supplied by the battery. In the case where the battery voltage is less than the load voltage required by the series and/or parallel LED circuit, a boost circuit can be used as pictured in FIGS. 8 a and 8 b . In this circuit an integrated circuit device, IC 1 801 is used to control the charging and discharging of an inductor L 1 803 . This integrated circuit may be one of several that are available such as the Texas Instruments TPS61040. After a charging cycle, the IC switches the circuit so that the inductor L 1 803 is permitted to discharge through the load, which in this case is the light emitting diodes 805 . The current is controlled via a feedback resistor R 1 806 . The value of the resistor is chosen to fix the maximum current that is permitted to flow through the load, which in this case, is one or more LEDs (LED 1 , LED 2 ) shown as 805 . This manner of control occurs because the voltage drop across R 1 806 is compared to an internally generated reference voltage at pin FB of IC 1 801 . When the two voltages are equal the current is considered fixed and will be controlled to that predetermined value. A diode D 3 802 is used to ensure protection of the IC 1 801 in case the battery source (not shown) is connected backwards. The diode 804 allows current flow through the LEDs 805 in only the forward, or light emitting direction. In this invention, such a circuit would be enclosed within the envelope of the bulb.
[0049] FIG. 8 b differs from FIG. 8 a in that it builds into the circuit an easy and inexpensive means of protecting the LEDs from excessive current flow and the runaway that results from high temperatures. In this circuit a resistor with a positive resistance rate of change with temperature, R 2 807 is placed in series with a fixed resistor. Resistor R 2 is physically located on the circuit board so as to be placed in the thermal pathway of heat emanating from the LEDs 805 . Therefore, when the temperature of the LEDs 805 increases, the resistance of R 2 807 also increases, and its resistance is added to that of R 1 806 . Since the voltage drop across these combined resistances appears on the feedback pin FB of IC 1 801 , the increased voltage is interpreted as a request for decreased current. Hence, the natural tendency of the LEDs 805 to draw more current that would ordinarily lead to the failure of the part is averted by introducing a self-limiting control function.
[0050] This circuit has the advantage of being very efficient and compact and having built into it a temperature regulation that allows the resulting system to automatically adapt to the thermal environment in which it is placed. Because of these attributes, it can, for example be put into a miniature lamp base of the kind used for flashlights (PR type flange base).
[0051] However, the remaining limitation of the circuit is that it can only boost voltage from a lower value to a higher value required by the LED load. Therefore, in situations where only one LED is required, but a higher input voltage is all that is available, the excess voltage will appear across the LED even if the circuits in FIG. 8 are used. This will cause an excessive current to be drawn, leading to premature failure of the LED and premature draining of the battery. To solve this problem we require a circuit that is still compact enough to fit into a bulb or bulb base, and that is capable of either raising or lowering the output voltage above or below the voltage of the incoming battery or other dc supply in order to maintain the desired current through the LED load. Hence this circuit would either boost the voltage if the input voltage were lower than required by the LED or reduce the voltage if it were higher than that required to sustain the necessary constant current through the LED. It is understood that LED here may refer to one or more LEDs in a series, parallel or series/parallel circuit. Furthermore, because of the deleterious effects of temperature, this circuit must have the ability to regulate the current through the LED depending on the ambient temperature. The ambient temperature may be determined by the environment as well as heat dissipated by the circuit and the LED.
[0052] Such a circuit is disclosed in FIG. 9 . This circuit utilizes a so-called Cuk converter that is ordinarily used as an inverting switching voltage regulator. Such a device inverts the polarity of the source voltage and regulates the output voltage depending on the values of a resistor bridge. In this invention, the inverter circuit has been altered in a unique fashion so that it acts to boost the voltage output or buck the voltage input in order to maintain a constant current through the load represented by one or more LEDs 905 . The circuit incorporates an integrated circuit IC 1 901 such as the National Semiconductor LM2611 Cuk Converter or equivalent. In this circuit, IC 1 's internal transistor is closed during the first cycle charging the inductor L 1 902 from the battery source indicated as Vbat. At the same time the capacitor C 2 904 charges inductor L 2 903 , while the output current to the LEDs 905 is supplied by inductor L 2 903 . In the next cycle the IC 1 901 changes state to permit the inductor L 1 902 to charge capacitor C 2 904 and L 2 903 to discharge through the LEDs 905 . The control of the charging power and current through the load is performed by the resistor network consisting of R 2 906 a and R 3 907 a . The overall value of these resistors together with the current passing through the LEDs 905 from ground, sets a voltage that appears on the feedback pin (FB) of IC 1 901 . Resistor 907 a has a positive temperature coefficient so that its resistance increases with temperature.
[0053] Because of thermal effects such as heat dissipation by the LEDs, heat produced by the IC 1 or other circuit components and the ambient environmental conditions, the current must also be altered to accommodate these changes. This is affected by a temperature dependent resistor R 3 . In FIG. 9 a , resistor R 3 907 a has a positive temperature coefficient in which the resistance increases with temperature. The additive effect of the series circuit with R 2 906 a means that as temperature rises, the overall resistance of the combination does also, leading to an increase in voltage drop. This in turn causes IC 1 to decrease the output current to the LEDs 905 . In FIG. 9 b the resistor network is comprised of resistors in parallel and series. In this instance, resistors R 2 and R 4 906 b , 908 are fixed and resistor R 3 907 b is temperature dependent with a positive temperature coefficient. The use of a parallel arrangement allows a greater freedom of choice of temperature dependence than a simple series arrangement. | The invention is a replacement for a conventional incandescent or halogen light bulb. Besides providing regular illumination, it has advantages over a conventional bulb while maintaining the bulb's decorative function, such as visual effects associated with the bulb's envelope or shade. The invention comprises a connector equivalent to a standard light bulb base, at least one light emitting diode (LED), and a driving circuit hosted on a module such as a printed circuit board and adapting the supply voltage to the requirements of the LED. Compensation for the effects of temperature may be included. The invention may also include other circuitry to support various enhanced features such as novel decorative features or control over the brightness, color, or other characteristics—all potentially varying over time or being controlled remotely. | 5 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit under 35 U.S.C. §119 of Korean Application No. 10-2008-0128659, filed Dec. 17, 2008, which is hereby incorporated by reference in its entirety.
BACKGROUND
[0002] The present disclosure relates to a structure including a spindle motor and a printed circuit board. An optical device is a device optically inputting data into an optical disk and outputting data from the optical disk, where the optical device includes an optical pickup accessing data of the optical disk, a spindle motor rotating the optical disk and a feeding motor moving the optical pickup toward inner and outer peripheries of the optical disk. A spindle motor performs the function of rotating a disk to enable an optical pickup which linearly reciprocates in an optical disk drive (ODD) to read data recorded on the disk. A spindle motor structure defines an assembled structure including a spindle motor and a printed circuit board driving the spindle motor.
BRIEF SUMMARY
[0003] The present disclosure intends to provide a spindle motor structure capable of easily coupling and separating a spindle motor from a printed circuit board.
[0004] The spindle motor structure according to one aspect of the present disclosure comprises: a spindle motor including a stator having a core wound with a coil and a rotor rotating about the stator; and a driving substrate aligned at an outer periphery of the rotor and soldered with driving control parts of the spindle motor including a plurality of circuit parts including a driving integrated circuit and the like; and a base on which the spindle motor and the driving substrate are installed, wherein the spindle motor is assembled with or dissembled from the base independently from the driving substrate.
[0005] The spindle motor structure according to another aspect of the present disclosure comprises: a spindle motor including a stator having a core wound with a coil and a rotor rotating about the stator; a driving substrate aligned at an outer periphery of the rotor and soldered with driving control parts of the spindle motor including a plurality of circuit parts including a driving integrated circuit and the like; a core substrate aligned at an inner side of the rotor and installed with the core and to which the coil is soldered and connected to the driving substrate; and a base on which the spindle motor, the driving substrate and the core substrate are installed, wherein the spindle motor or the core substrate is assembled with or dissembled from the base independently from the driving substrate.
BRIEF DESCRIPTION OF DRAWINGS
[0006] FIG. 1 is a perspective view illustrating an imaginary comparative exemplary embodiment for comparing with exemplary embodiments of the present disclosure.
[0007] FIG. 2 is a cross-sectional view illustrating a spindle motor and a printed circuit board according to a first exemplary embodiment of the present disclosure.
[0008] FIG. 3 is a perspective view illustrating a spindle motor structure of FIG. 2 .
[0009] FIG. 4 is a perspective view illustrating a spindle motor structure according to a second exemplary embodiment of the present disclosure.
[0010] FIG. 5 is a perspective view illustrating a spindle motor structure according to a third exemplary embodiment of the present disclosure.
[0011] FIG. 6 is a perspective view illustrating a spindle motor structure according to a fourth exemplary embodiment of the present disclosure.
DETAILED DESCRIPTION
[0012] FIG. 1 is a perspective view illustrating an imaginary comparative exemplary embodiment for comparing with exemplary embodiments of the present disclosure, where an assembled structure of a spindle motor and a printed circuit board is shown.
[0013] Referring to FIG. 1 , a spindle motor 10 is formed with a bearing housing (not shown) press-fitted by a bearing (not shown), and the bearing is supportively and rotatably installed by a lower portion of the rotation shaft 11 .
[0014] A stator including a core 13 a and a coil 13 b is coupled to an outer periphery of the bearing housing, and a rotor including a rotor yoke 15 a and a magnet (not shown) is coupled to an outer periphery at an upper side of the rotation shaft 11 .
[0015] The bearing housing is vertically installed with a metallic base 20 on which a printed circuit board (substrate 30 ) mounted with a plurality of parts is installed.
[0016] The substrate 30 is connected with a lead wire 13 bb of the coil 13 b by way of soldering and is supportively soldered by one side of the core 13 a . The substrate 30 also serves to insulate the coil 13 b and the base 20 . If the substrate 30 fails to insulate the coil 13 b and the base 20 , a separate insulator may be installed.
[0017] The spindle motor structure as illustrated in FIG. 1 is coupled by the stator at an area of the substrate 30 at an inner side of the rotor yoke 15 a , whereby it makes it difficult to separate the substrate 30 from the spindle motor 10 in a case the substrate 30 is to be replaced for changing the characteristic of the spindle motor 10 or for being compatible with the product side.
[0018] Another drawback is that the stator is coupled at an area of the substrate 30 inside the rotor yoke 15 a , which makes it difficult to perform the coupling process of the spindle motor 10 and the substrate 30 .
[0019] Thus, the present disclosure intends to solve the aforementioned conventional drawbacks and exemplary embodiments of the present disclosure to improve the drawbacks will be described in the following.
[0020] FIG. 2 is a cross-sectional view illustrating a spindle motor and a printed circuit board according to a first exemplary embodiment of the present disclosure, and FIG. 3 is a perspective view illustrating a spindle motor structure of FIG. 2 .
[0021] Referring to FIGS. 2 and 3 , a spindle motor 100 and a driving printed circuit board (substrate 210 ) are coupled to a metallic base 310 .
[0022] Hereinafter, in the description of directions and surfaces of constituent elements including the base 310 , a surface and a direction facing a vertical upper side of the base 310 are referred to as ‘upper surface and upper side’ and a surface and a direction facing a lower side of the base 310 are referred to as ‘lower surface and lower side’.
[0023] The spindle motor 100 includes a bearing housing 110 which in turn is provided in a cylindrical shape with an open bottom, where a lower end open surface of the bearing housing 120 is insertedly coupled with a coupling hole 312 formed at the base 310 .
[0024] The bearing housing 110 is press-fitted by a bearing 120 which in turn is rotatably and supportively installed by a lower outer periphery of rotation shaft 130 . The opened lower surface of the bearing housing 110 is coupled with a thrust stopper 141 that prevents the rotation shaft 130 from disengaging toward downstream of the bearing housing 110 .
[0025] A stator 150 has a core 151 coupled to the outer periphery of the bearing housing 110 , and a coil 155 wound on the core 151 . A rotor 160 includes a rotor yoke 161 supported on the rotation shaft 130 exposed to the outside of the bearing housing 110 , and a magnet 165 coupled to the rotor yoke 161 in opposition to the stator 150 .
[0026] Accordingly, when a current is applied to the coil 155 , the rotor 160 and the rotation shaft 130 are rotated through electromagnetic fields formed between the coil 155 and the magnet 165 .
[0027] The rotor yoke 161 also serves to function as a turn table on which a disk 50 is mounted. A felt 181 is installed at an upper perimeter of the rotor yoke 161 for inhibiting the mounted disk 50 from slipping.
[0028] A clamp device 170 elastically supporting the disk 50 and inhibiting the disk 50 from disengaging upward of the rotor yoke 161 is installed on the outer perimeter of the rotor yoke 161 coupled to the rotation shaft 130 , in order to align the center of the mounted disk 50 with the center of the rotation shaft 130 . The coil 155 of the spindle motor 100 is connected to the driving substrate 210 to receive an external electric power.
[0029] The present exemplary embodiment of the present invention is so provided as to easily connect the coil 155 of the spindle motor 100 and the driving substrate 210 , which is described in the following.
[0030] Referring to FIGS. 2 and 3 , the driving substrate 210 is provided at the outer periphery of the rotor yoke 161 and is coupled at the lower surface thereof to an upper surface of the base 310 using an adhesive or a two-sided tape.
[0031] To this end, an area of the driving substrate 210 corresponding to an upper surface area of the base 310 for mounting the rotor yoke 161 is formed thereinside with a sink 210 a . The driving substrate 210 is formed with a connection pattern 211 to which a lead wire 155 a of the coil 155 is connected using solder, and is also installed with a plurality of circuit parts including a driving integrate circuit (IC. 213 ) and the like.
[0032] An adhesive 410 is coated on an upper surface of the base 310 inside the rotor yoke 161 . The adhesive 410 supports one side of the core 151 and simultaneously insulates the metallic base 310 and the coil 155 . An area of the adhesive 410 for supporting the core 151 is formed with a protrusion 410 a toward the core 151 side.
[0033] In the first exemplary embodiment of the present invention, the driving substrate 210 is aligned at the outer periphery of the spindle motor 100 to enable the lead wire 155 a of the coil 155 to be easily connected to the driving substrate 210 .
[0034] In a case of separating the driving substrate 210 and the spindle motor 100 for replacing the driving substrate 210 , the only procedure is to simply detach the lead wire 155 a of the coil 155 from the driving substrate 210 .
[0035] Unexplained reference numeral 145 in FIGS. 2 and 3 defines a thrust plate for inhibiting the rotation shaft 130 and the thrust stopper 141 from being worn out by supporting the lower portion of the rotation shaft 130 .
[0036] Now, a second exemplary embodiment of the present invention will be described.
[0037] FIG. 4 is a perspective view illustrating a spindle motor structure according to a second exemplary embodiment of the present disclosure, from which a structure alone which is different from that of the first exemplary embodiment will be described.
[0038] Referring to FIG. 4 , an upper surface of the base 310 inside the rotor yoke 161 is coupled to the lower surface of a core substrate 420 using an adhesive or a two-sided tape. The core substrate 420 serves to insulate the metallic base 310 and the coil 155 , and to support one side of the core 151 . The core 151 is supported at one side thereof by the core substrate 420 by a solder 422 .
[0039] The coil 155 and a driving substrate 220 are interconnected via a flexible flat cable 510 , an electric line or other electrically connecting means.
[0040] To be more specific, one side of the flexible flat cable 510 is fixedly coupled to the core substrate 420 to allow the lead wire 155 a of the coil 155 being connected using solder, while the other side of the flexible flat cable 510 is exposed to the outside of the rotor yoke 161 to be connected using solder to a connection pattern 223 formed at the driving substrate 220 .
[0041] A tip end of the driving substrate 220 formed at the connection pattern 223 is formed with a support groove 220 aa into which a center of the flexible flat cable 510 is supportively inserted, in order to facilitate the soldering of the flexible flat cable 510 and the driving substrate 220 .
[0042] When the driving substrate 220 and the core substrate 420 are coupled to the base 310 , an upper surface of the driving substrate 220 and an upper surface of the core substrate 420 may be positioned on the same planar surface, in order to facilitate the soldering of the flexible flat cable 510 and the driving substrate 220 .
[0043] In the second exemplary embodiment of the present invention, the driving substrate 220 is arranged on an outer periphery of the spindle motor 100 , and an area of the flexible flat cable 510 connected to the driving substrate 220 is exposed outside of the rotor yoke 161 . Accordingly, it is easy to connect the flexible flat cable 510 to the driving substrate 220 and to separate the driving substrate 220 from the flexible flat cable 510 . A flexible substrate may be used instead of the flexible flat cable 510 .
[0044] Now, a third exemplary embodiment of the present invention will be described.
[0045] FIG. 5 is a perspective view illustrating a spindle motor structure according to a third exemplary embodiment of the present disclosure, from which a structure alone which is different from that of the second exemplary embodiment will be described.
[0046] Referring to FIG. 5 , a core substrate 420 coupled to an upper surface of the base 310 is connected to a connector 520 . The connector 520 includes a coupling unit 521 coupled to an outer periphery of the core substrate 420 , and a support unit 525 bent from an upper end of the coupling unit 521 toward a driving substrate 230 side.
[0047] The support unit 525 is embedded with a connection terminal 520 a , and one side of the connection terminal 520 a is exposed toward the core substrate 420 side, where the lead wire 155 a of the coil 155 is connected using solder. The driving substrate 230 is formed with a connection terminal 235 inserted into the other side of the connector 520 and connected to the connection terminal 520 a . A tip end of the driving substrate 230 formed with the connection terminal 235 is formed with a support groove 230 aa into which the support unit 525 of the connector 520 is supportively inserted.
[0048] In the third exemplary embodiment of the present invention, the driving substrate 230 is arranged on an outer periphery of the spindle motor 100 , and an area of the connector 520 connected to the driving substrate 230 is exposed outside of the rotor yoke 161 . Accordingly, it is easy to connect the connector 520 to the driving substrate 230 and to separate the driving substrate 220 from the connector 520 .
[0049] Now, a fourth exemplary embodiment of the present invention will be described.
[0050] FIG. 6 is a perspective view illustrating a spindle motor structure according to a fourth exemplary embodiment of the present disclosure, from which a structure alone which is different from that of the third exemplary embodiment will be described.
[0051] Referring to FIG. 6 , an upper surface of a base 320 inside the rotor yoke 161 is coupled to the lower surface of a core substrate 430 using an adhesive or a two-sided tape. The core substrate 430 serves to insulate the metallic base 310 and the coil 155 , and to support one side of the core 151 . The core 151 is supported at one side thereof by the core substrate 430 by a solder 432 .
[0052] The core substrate 430 is connected to a substrate 24 . To this end, the core substrate 430 and the driving substrate 240 are respectively connected to a connection pattern 434 and an access pattern 241 , where the connection pattern 434 is connected to a lead wire 155 a of the coil 155 by a soldering process.
[0053] The connection pattern 434 is formed at an upper surface of a protruding piece 436 protruding outside from an outer periphery of the core substrate 430 , and a tip end of a driving substrate 240 formed with the connection pattern 241 is formed with a support groove 240 aa into which the protruding piece 436 is supportively inserted, in order to facilitate the connection between the connection pattern 434 and the access pattern 241 .
[0054] When the core substrate 430 and the driving substrate 240 are coupled to a base 320 , an upper surface of the core substrate 430 and an upper surface of the driving substrate 240 may be positioned on the same planar surface, in order to facilitate the connection of the connection pattern 434 and the access pattern 241 .
[0055] A gap may exist between a tip end of the protruding piece 436 and that of the driving substrate 240 when the protruding piece 436 is inserted into the support groove 240 aa . If the solder that has been introduced into the gap exceeds more than a predetermined amount, the solder may flow backward to an upper surface of the protruding piece 436 and to that of the driving substrate 240 to flow over the upper surface of the protruding piece 436 and that of the driving substrate 240 . This may cause generation of short-circuit.
[0056] In order to inhibit the backward flow of the solder, a discharge hole 322 is formed at an area between the connection pattern 434 and the access pattern 241 , i.e., an area of the base 320 corresponding to a gap between a tip end of the protruding piece 436 and a cross-section of the driving substrate 240 . As a result, the solder that has introduced into the gap comes into the discharge hole 322 to be attached to the discharge hole 322 by tension, or to be discharged outside via the discharge hole 322 , thereby inhibiting the generation of short-circuit.
[0057] In the fourth exemplary embodiment of the present invention, the driving substrate 240 is arranged on an outer periphery of the spindle motor 100 , and an area of the connection pattern 434 of the core substrate 430 connected to the driving substrate 240 is exposed outside of the rotor yoke 161 . Accordingly, it is easy to connect the core substrate 430 to the driving substrate 220 and to separate the driving substrate 240 from the core substrate 430 .
[0058] In the spindle motor structure according to the present invention, a substrate is arranged on an outer periphery of a rotor of the spindle motor, and an area connected to a coil of the spindle motor is exposed outside of the spindle motor to be connected to the substrate. Accordingly, it is easy to connect the spindle motor to the substrate and to separate the substrate from the spindle motor, whereby only the substrate may be replaced to standardize and common-use the spindle motor.
[0059] Any reference in this specification to “one embodiment,” “an embodiment,” “exemplary embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the disclosure. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to affect such feature, structure, or characteristic in connection with others of the embodiments.
[0060] Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this invention. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawing and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art. | A spindle motor structure is disclosed wherein the spindle motor structure comprises a spindle motor including a stator having a core wound with a coil and a rotor rotating about the stator; and a driving substrate aligned at an outer periphery of the rotor and soldered with driving control parts of the spindle motor including a plurality of circuit parts including a driving integrated circuit and the like; and a base on which the spindle motor and the driving substrate are installed, wherein the spindle motor is assembled with or dissembled from the base independently from the driving substrate. | 6 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention generally relates to exploration for hydrocarbons involving electrical investigations of a borehole penetrating an earth formation. More specifically, this invention relates to highly localized borehole investigations employing the introduction and measuring of individual survey currents injected into the wall of a borehole by capacitive coupling of electrodes on a tool moved along the borehole with the earth formation.
[0003] 2. Background of the Art
[0004] Electrical earth borehole logging is well known and various devices and various techniques have been described for this purpose. Broadly speaking, there are two categories of devices used in electrical logging devices. In the first category, a measure electrode (current source or sink) are used in conjunction with a diffuse return electrode (such as the tool body). A measure current flows in a circuit that connects a current source to the measure electrode, through the earth formation to the return electrode and back to the current source in the tool. In inductive measuring tools, an antenna within the measuring instrument induces a current flow within the earth formation. The magnitude of the induced current is detected using either the same antenna or a separate receiver antenna. The present invention is a hybrid of the two.
[0005] There are several modes of operation of prior art devices: in one, the current at the measuring electrode is maintained constant and a voltage is measured while in the second mode, the voltage of the electrode is fixed and the current flowing from the electrode is measured. Ideally, it is desirable that if the current is varied to maintain constant the voltage measured at a monitor electrode, the current is inversely proportional to the resistivity of the earth formation being investigated. Conversely, it is desirable that if this current is maintained constant, the voltage measured at a monitor electrode is proportional to the resistivity of the earth formation being investigated. Ohm's law teaches that if both current and voltage vary, the resistivity of the earth formation is proportional to the ratio of the voltage to the current.
[0006] Techniques for investigating the earth formation with arrays of measuring electrodes have been proposed. See, for example, the U.S. Pat. No. 2,930,969 to Baker, Canadian Patent No. 685727 to Mann et al., U.S. Pat. No. 4,468,623 to Gianzero, and U.S. Pat. No. 5,502,686 to Dory et al. and U.S. Pat. No. 6,714,014 to Evans et al, each of which provide additional background information to this disclosure.
[0007] In the prior art devices, current is actively focused in the direction perpendicular to the borehole wall. There is a technical challenge to provide stable focusing conditions during the logging if the borehole walls are rough or the mud is very conductive. As soon as the focusing conditions are not met, the measurements are responsive to a considerable extent to the properties of the mud. The prior art devices do not specifically address the problems due to irregularities in the wall surface of the wellbore. If the wall of the wellbore is irregular, the measuring current path becomes distorted and the relationship between measured impedance and earth formation resistivity changed as result.
SUMMARY OF THE INVENTION
[0008] One embodiment of the invention is an apparatus for evaluating an earth formation. The apparatus includes at least one coil on a logging tool conveyed in a borehole in the earth formation. Passage of a current through the coil induces an electrical current in the earth formation. At least two electrodes associated with the logging tool and in proximity to a wall of the borehole have a potential difference that is indicative of a property of the earth formation. The at least one coil may be mounted on a mandrel of a downhole assembly. The at least one coil may include at least three planar coils with their normals distributed azimuthally about an axis of the logging tool. At least one of the three coils may operate at a different frequency from another one of the at least three coils. The electrodes may be positioned on a first pad extendable from a mandrel of the downhole assembly. A second pad may be provided on an opposite side of the mandrel from the first pad. The two electrodes may further include three pairs of electrodes, each pair being at a different azimuthal position on the pad. The apparatus may further include a processor which uses the difference to estimate a resistivity property of the earth formation. The logging tool may be conveyed into the borehole using a wireline, a drilling tubular and/or a slickline. The difference may be in quadrature with the current in the coil.
[0009] Another embodiment of the invention is a method of evaluating an earth formation. A current is passed through at least one coil on a logging tool conveyed in a borehole in the earth formation so as to induce an electrical current in the formation. A difference in electrical potential between at least two electrodes in proximity to a wall of the borehole is detected.
[0010] Another embodiment of the invention is a computer-readable medium for use with an apparatus for evaluating an earth formation. The apparatus includes at least one coil on a logging tool conveyed in a borehole in the earth formation. Passage of current through the coil induces an electrical current in the earth formation. The apparatus also includes two electrodes in proximity to a wall of the borehole. The medium includes instructions which enable a processor to determine from a difference in electrical potential between the two electrodes a property of the earth formation. The medium may include a RAM, a ROM, an EPROM, an EAROM, a flash memory, and/or an optical disk.
BRIEF DESCRIPTION OF THE FIGURES
[0011] The present invention is best understood with reference to the accompanying figures in which like numerals refer to like elements and in which:
[0012] FIG. 1 shows an exemplary logging tool suspended in a borehole;
[0013] FIG. 2 is a mechanical schematic view of an exemplary imaging tool;
[0014] FIG. 3 a is a schematic illustration of three coils on a tool of the present invention;
[0015] FIG. 3 b illustrates an embodiment of the present invention showing a single coil on a mandrel and pad mounted electrodes;
[0016] FIG. 3 c is an equivalent circuit diagram of a resistivity imaging tool;
[0017] FIGS. 4 a and 4 b shows an arrangement of pad mounted electrodes and a pad mounted coil;
[0018] FIGS. 5 and 6 show exemplary models used for evaluation of the tool configuration of FIG. 3 b;
[0019] FIG. 7 shows the response at different azimuths for the model of FIG. 5 with no rugosity;
[0020] FIG. 8 shows the K-factor for the curves of FIG. 7 for azimuths of 10° and 20°;
[0021] FIG. 9 shows the results of applying the K-factor to the 10° and 20° azimuth curves;
[0022] FIG. 10 shows the response at different standoffs for the model of FIG. 5 ; and
[0023] FIG. 11 shows the effect of rugosity on measurements made by an exemplary tool. of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0024] FIG. 1 shows an imaging tool 10 suspended in a borehole 12 , that penetrates earth formations such as 13 , from a suitable cable 14 that passes over a sheave 16 mounted on drilling rig 18 . The cable 14 includes a stress member and seven conductors for transmitting commands to the tool and for receiving data back from the tool as well as power for the tool. The tool 10 is raised and lowered by draw works 20 . Electronic module 22 , on the surface 23 , transmits the required operating commands downhole and in return, receives data back which may be recorded on an archival storage medium of any desired type for concurrent or later processing. The data may be transmitted in analog or digital form. Data processors such as a suitable computer 24 , may be provided for performing data analysis in the field in real time or the recorded data may be sent to a processing center or both for post processing of the data.
[0025] FIG. 2 a is a schematic external view of a borehole sidewall imager system. The tool 10 comprising the imager system includes resistivity arrays 26 . Optionally, the imager system may include other sensors, such as a mud cell 30 or a circumferential acoustic televiewer 32 . Electronics modules 28 and 38 may be located at suitable locations in the system and not necessarily in the locations indicated. The components may be mounted on a mandrel 34 in a conventional well-known manner. The outer diameter of the assembly may be about 5 inches and about fifteen feet long. An orientation module 36 including a magnetometer and an accelerometer or inertial guidance system may be mounted above the imaging assemblies 26 and 32 . The upper portion 38 of the tool 10 contains a telemetry module for sampling, digitizing and transmission of the data samples from the various components uphole to surface electronics 22 in a conventional manner. If acoustic data are acquired, they are preferably digitized, although in an alternate arrangement, the data may be retained in analog form for transmission to the surface where it is later digitized by surface electronics 22 . Also shown in FIG. 2A are three resistivity arrays 26 (a fourth array is hidden in this view.
[0026] Turning to FIG. 3 a , a simplified exemplary diagram of three vertical coils 101 , 103 , 105 of the present invention on a mandrel (not shown) of the present invention is shown. FIG. 3 b show one of the coils 103 mounted inside or on the surface of mandrel 121 . Arms depicted schematically by 131 , 137 extend a pad 133 radially outward from the mandrel to make contact with the borehole wall (not shown). Disposed on the pad 133 are electrodes depicted schematically by 135 a , 135 b . Another pad (not shown) may be positioned on the opposite side of the coil 103 from the pad 133 . In an alternate embodiment of the invention, a single coil may be mounted on the mandrel with its axis along the tool axis.
[0027] This tool may be referred to as a “mixed mode” tool in that an inductive source is used and galvanic currents are detected by the electrodes. Specifically, a plurality of long transversal rectangular coils with the magnetic moment perpendicular to the axis of the borehole are used. Each transmitter loop is centered in the borehole and electrode pairs are placed on the pad attached to the borehole wall. This is a generic design and further variants are identified below. In a practical design each transmitted coil serves two pads with a number of electrode pairs on each pad. Each transmitter coil may have its own operating frequency to avoid the interference of the neighboring induction coils. By using an induction transmitter, an electric current can be injected into the formation.
[0028] (1),
[0000] At a low frequency and relatively close to the induction loop, the electric field does not depend on the conductivity of the formation and can be increased simply by increasing the operating frequency ω. In the case of a galvanic injection and non-conductive mud the injection current must go through quite a large capacitive resistance. This can be better understood from the simplified schematics in FIG. 3 c where the capacitor C m represents the capacitance between the injection electrodes and the formation, and R f corresponds to the resistivity of the formation. The current I f injected into the formation can then be expressed as
[0000]
I
f
=
U
ab
2
X
c
+
R
f
,
X
c
=
1
i
ω
C
m
,
C
m
≈
ɛ
S
d
,
(
2
)
[0000] where S is the area of the electrode, U ab is the applied potential difference between the injection electrodes a and b. Because C m is inversely proportional to the distance d between the current electrode and the formation, the amount of the current injected into the formation will drop with increasing standoff. A long induction transmitter is free of such high sensitivity to the standoff value and well suited to the nonconductive environment.
[0029] If only electric field is measured, the measurements will be very sensitive to a relative variation of resistivity in the adjacent formation. To derive the absolute resistivity of the formation, some additional induction measurements and their combination with the galvanic readings are helpful.
[0030] The response of the tool design of FIG. 3 b was tested on a number of different models. One of these is illustrated in FIG. 5 . Shown therein is a borehole 151 with a diameter of 8.5 inches (21.6 cm). The mandrel is shown as 121 , a pad by 132 and an arm on which the pad is carried by 131 . The tool has a variable standoff 133 . The formation comprises beds of thickness 0.5 inches, 1 inch, 2 inches, 3 inches and 4 inches (1.27 cm, 2.54 cm, 5.08 cm, 7.62 cm and 10.16 cm respectively). The layers had resistivities ρ and relative dielectric constant ∈ of (10 Ω-m, 10) and (1 Ω-m, 20) respectively.
[0031] In a second model shown in FIG. 6 , the formation had a uniform ρ=1Ω-m, ε=20, The standoff was fixed at ⅛ inches (3.18 mm). However, the borehole was rugose, with a depth of rugosity varied between ¼ inches and ¾ inches (6.35 mm and 19.1 mm). Response to other models which represented a combination of the features of the models of FIGS. 5 and 6 were also simulated.
[0032] In the modeling, a 0.914-m long transmitter with a width of 0.1524 m was used. The operating frequency was 100 kHz. In the case of lower or higher frequencies (up to several MHz), the response can be approximately derived simply by linear resealing of the signal corresponding to 100 kHz frequency. A transmitter loop is placed in the nonconductive borehole environment with the radius of the borehole 10.795 cm. An electrode spacing of 0.25 inches or 0.5 inches (0.63 cm and 1.27 cm) was used to measure a potential drop U z in the vertical direction parallel to the borehole axis.
[0033] The typical behavior of the electrical signal to the model is presented in FIG. 7 . The three curves 201 , 203 and 205 in this figure correspond to azimuths of 0°, 10° and 20° of the receiver's electrode pairs. The abscissa in the figure is the logging depth in inches and the ordinate is the signal (the voltage difference between the button electrodes). The 10° and 20° deg. azimuth curves can be shifted to the 0° deg. curve by applying a K-factor that is about 1.07 for the 10° curve and 1.27 for the 20-degree curve. The division result of 10° and 20° curves by the 0°. curve is presented in FIG. 8 as the curves 221 and 223 , while the result of K-factor application to the original curves from FIG. 7 is presented in FIG. 9. 241 is the original 0° azimuth response to the model from FIG. 7. 243 is the corrected 10° azimuth response to the model while 245 is the corrected 20° azimuth response. From FIG. 9 we it can be seen that it is possible to cover an azimuth range of 40° (from −20° to +20°) by having additional columns of electrodes on the pad of FIG. 3 b.
[0034] The dynamic range, which is the ratio between the maximum and minimum reading along the logging depth, is changing between 5 and 6 considering layers 1 in. and larger. We define a Normalized Dynamic Range (NDR) as a ratio of a signal dynamic range to a resistivity contrast of the corresponding media. In the model of FIG. 5 the resistivity contrast of the neighboring layers is 10, so that the NDR of the mixed mode arrangement is approximately 0.55.
[0035] Next, examples showing the influence of the distance between the receiver electrodes and the borehole wall are presented. The results of mathematical modeling for the same benchmark model of FIG. 5 are presented in FIG. 10 . The electrode spacing is 0.25 inches (6.35 mm). For the ⅛ inch (3.18 mm) standoff 263 the NDR drops to 0.3 in the 1 inch (2.54 cm) thick layer and decreases to 0.2 and 0.13 for the ¼ in (6.35 mm) 265 and ½ in (1.27 cm) 267 standoff, correspondingly. For the 2 in (5.08 cm) layer thickness the NDR parameter is as much as twice larger than for 1 in (2.54 cm) layers. The imperfections due to standoff are more noticeable in the conductive layers, and there is no signal imperfection in the resistive layers thicker than 2 in (5.08 cm).
[0036] Turning next to FIG. 11 , the sensitivity of the measured electric field for the model of FIG. 6 as a function of borehole rugosity is shown. The curves 281 , 283 and 285 correspond to rugosity of ¼ inch (6.3 mm), ½ inc (1.27 cm) and ¾ inches (1.91 cm) respectively. This is a model with no resistivity contrasts, but the signal from the rugose wall has all the features of a structure—boundaries and resistivity contrast. Of course, these artifacts are more pronounced for the ½ inc (1.27 cm) and ¾ inches (1.91 cm) rugosity than for the ¼ inch (6.3 mm) rugosity. Based on extensive modeling results (not shown), we have concluded that in the case of a 0.25-in. rugosity depth, all 1-in. beds are well resolved (NDR>0.2) and the presence of the rugosity in some beds does not destroy the readings in front of neighboring beds. The situation deteriorates as the rugosity is increased to 0.5 in. and 0.75 in.
[0037] The processing of the data may be done with the use of a computer program implemented on a suitable machine readable medium that enables the processor to perform the control and processing. The term processor as used in this application is used in its traditionally-broad sense and is intended to include such devices as single-core computers, multiple-core computers, distributed computing systems, field programmable gate arrays (FPGAs) and the like. The machine readable medium referenced in this disclosure is any medium that may be read by a machine and may include magnetic media, RAM, ROM, EPROM, EAROM, flash memory and optical disks. The processing may be done downhole or at the surface. In an alternative embodiment, part of the processing may be done downhole with the remainder conducted at the surface.
[0038] The invention has been described with reference to a wireline conveyed logging tool. The principles discussed above may also be used in a measurement-while-drilling (MWD) implementation in which the logging tool is part of a bottomhole assembly (BHA) conveyed on a drilling tubular. The method may also be used with the logging tool conveyed on a slickline. For the purposes of the present invention, the term “downhole assembly” may be used to describe a BHA as well as configurations in which the logging tool is part of an assembly conveyed on a wireline or slickline.
[0039] The following definitions are helpful in understanding the present invention.
[0000] coil: one or more turns, possibly circular or cylindrical, of a current-carrying conductor capable of producing a magnetic field;
EAROM: electrically alterable ROM; EPROM: erasable programmable ROM; flash memory: a nonvolatile memory that is rewritable; induction: based on a relationship between a changing magnetic field and the electric field created by the change; machine readable medium: something on which information may be stored in a form that can be understood by a computer or a processor; mandrel: A bar, shaft or spindle around which other components are arranged or assembled. The term has been extended in oil and gas well terminology to include specialized tubular components that are key parts of an assembly or system; misalignment: the condition of being out of line or improperly adjusted; Optical disk: a disc shaped medium in which optical methods are used for storing and retrieving information; Position: an act of placing or arranging; the point or area occupied by a physical object ROM: Read-only memory; Resistivity: electrical resistance of a conductor of unit cross-sectional area and unit length. Determination of resistivity is equivalent to determination of its inverse (conductivity); Rugosity: A qualitative description of the roughness of a borehole wall. Alternatively, the term pertains to a borehole whose diameter changes rapidly with depth.
[0052] While the foregoing disclosure is directed to the preferred embodiments of the invention, various modifications will be apparent to those skilled in the art. It is intended that all variations within the scope and spirit of the appended claims be embraced by the foregoing disclosure. | A mixed mode tool uses an inductive source and detects galvanic currents and/or potentials at electrodes in proximity to a borehole wall to produce a resistivity image of the earth formation. | 6 |
RELATED APPLICATION
This application is a continuation-in-part of U.S. patent application Ser. No. 09/034,720, filed Mar. 4, 1998, entitled Secure Content Distribution System, and incorporates by reference U.S. patent application Ser. No. 09/168,080 entitled Digital Rights Management System, filed on even date herewith and assigned to the same assignee as the present invention.
FIELD OF THE INVENTION
The present invention relates to generation, management and replacement of encryption keys, and more particularly relates to methods for generation, management and replacement of encryption keys in connection with the distribution and management of digital rights in encrypted text or other data.
BACKGROUND OF THE INVENTION
The ubiquitous nature of the Internet in the business community, and the increasing penetration of the Internet into homes, has generated a new era in the distribution of information to interested recipients. The ease with which volumes of information can be disseminated around the world over the Internet has been demonstrated and documented.
While this ease of distribution is valuable and desirable, in many instances, the information—whether text, data, code, graphics or some other form—is valuable and its owners prefer that this information not be distributed freely. In such circumstances, the need for a suitable form of protection for the information becomes critical. A conventional approach has been the use of encryption, typically using a combination of a public key and a private key. Such techniques are well known and offer significant security when used properly.
One difficulty with conventional applications of such techniques, however, is that the protected information is, at some point, decrypted for viewing or other use in an insecure environment. At that point, the information is able to be disseminated contrary to the wishes of the owner of the information—an undesirable result.
U.S. patent application Ser. No. 09/034,720 describes a secure reader for such information, typically though not necessarily for use with text, in which a unique private key is associated with each reader and a public key associated with that reader is available to the owner of the protected information. The owner of the information encrypts the information with the public key, and the information is thereafter downloaded to the associated reader. The reader then decrypts the information with the internally-maintained private key, allowing the user to view the decrypted information.
While this approach offers many advantages, it is important that the public and private security keys not be readily available together during the manufacturing process to avoid potential abuse such as theft or hacking. While there are numerous techniques for attempting to maintain security for encryption keys in a manufacturing environment, most currently available techniques involve both public and private keys (i.e., key pairs) being jointly available at some point during the manufacturing process. One approach is for a remote source (for example, the information owner) to generate the key pairs and to send the private keys to the factory during production. This has the obvious disadvantage that the private keys are, at some point, known to the factory.
Another approach is for the factory to be allowed to generate the key pairs, in which case the public keys will be provided to the owner of the information for use in subsequent downloads of protected information. This, too, suffers from the problem that the key pairs are both available at the factory, and therefore unacceptably subject to theft or other abuse.
Beyond just the manufacturing issues, additional issues exist with secure systems when the reader requires service, is lost, or is otherwise replaced. In most instances, the reader will include significant amounts of purchased content, such that the user will want to have transferred to the new reader all titles or other digital rights that existed in information maintained on the prior reader. With conventional techniques, this again requires that the key pair be available during the manufacturing process; this is, in general, an unacceptable security risk.
SUMMARY OF THE INVENTION
The present invention overcomes many of the limitations of the prior art and, more particularly, provides a secure system and method for generating and distributing encryption keys both during manufacturing and thereafter, and for transferring existing digital rights in data from a first device to a replacement or other device.
In particular, the system and method for generating key pairs during the manufacturing process makes it possible to generate the key pairs without both keys in the key pair existing in an insecure environment at any time. More specifically, the present invention permits distributed generation of the public and private keys, with the factory installing secure versions of the key pair in the reading device. The reading device, or reader, is then used to transport the public key in a secure way to an authentication server.
To implement the present invention, the factory public key must be registered with the authentication server, and the authentication server public key must be registered with the factory server or other equipment. The factory equipment automatically generates an encrypted form of the public/private key pair and further generates an appropriate, unique indicia indicative of the associated device. This indicia can also be read directly from the device if the device has an unique indicia built into the hardware, such as a “silicon serial number” available in many CPU and peripheral integrated circuits. The indicia and the new public key of the device is then encrypted with the public key of the authentication server, and appends to the indicia the authentication server public key. The indicia and appended public key are then hashed and signed with the factory private key to generate a device certificate, which is sent to the electronic reader.
The electronic reader receives the device certificate, authenticates it and, if authentic, compares a portion of the indicia to ensure the certificate is truly intended for the recipient reader. If so, the device private key is installed as well as the authentication server public key; the remainder of the indicia and the encrypted device public key are stored and the reader is ready to ship.
Once the reader is received by the user, the user registers the reader with an appropriate entity having certificate authority such as the authentication server. This is accomplished by the device uploading the encrypted indicia and encrypted device public key, either directly or through another computer connected to the Internet. Once uploaded, the authentication server decrypts the device public key and authenticates the package using the factory public key. If authentic, it registers the device public key in the database. Additional user-specific information is typically encoded by the authentication server to generate a user certificate, which is encrypted with the device public key and signed by the private key of the certificate authority. The User Certificate contains a different public/private key pair that will be used for decrypting content. The public key is registered in the authentication server database, and the private key is put into a secure archive. The sequence number of the certificate is set to a low number. The user certificate is then provided to and installed by the reader. The user certificate is then decrypted and authenticated with the device private key and the authentication server public key both installed at the factory, and the result of the authentication process is provided to the authentication server. If successful, the user certificate is now associated with the specific electronic reader and the process completes.
If at some later time the electronic reader needs to be serviced or replaced for any reason, the user initiates a certificate movement which causes the authentication server to start a revocation process. The revocation process generates a revocation certificate. The certificate is sent to the first device where it is decrypted and authenticated. The device responds back to the authentication server or other appropriate certificating authority with a revocation acknowledge, and the authentication server authenticates the response. If authenticated, the revocation is recorded as successful and the first reader is no longer authorized to view the protected information.
The authentication server or other certificating authority then generates a new user certificate using the old public and private keys This is done by looking up the user's public key in the key database, and retrieving the private key from the secure archive. It also looks up the sequence number of the user certificate and increases the value. The new sequence number is built into the customer certificate. The new user certificate is then sent to and installed by the second device, after which the second device sends a confirmation to the authentication server. This permits the user to continue to exercise all rights he had with the first unit, including reading, downloading or otherwise using the protected information in any permissible way.
The foregoing summary of the present invention may be better appreciated from the following Detailed Description of the Invention, taken together with the attached Figures.
FIGURES
FIG. 1 shows generally a secure distribution system for management of digital rights in accordance with the present invention.
FIG. 2 shows in flow diagram form an exemplary implementation of a secure key pair generation and installation system and method in accordance with the present invention.
FIG. 3 shows in flow diagram form the registration of an electronic reader and the certificate generation associated therewith.
FIGS. 4A-4B shows in flow diagram form an implementation of the steps for generating and authenticating a user certificate as part of the registration process of FIG. 3 .
FIG. 5 shows in flow diagram form the movement of a user certificate and associated key pair from a first user device to a second user device.
FIG. 6 shows in flow diagram form the details of the revocation process included in the overall process of FIG. 5 .
DETAILED DESCRIPTION OF THE INVENTION
By way of example only, the invention described hereinafter may be used with the secure content distribution system shown and described in U.S. patent application Ser. No. 09/034,720, entitled Secure Content Distribution System, filed Mar. 4, 1998, and U.S. patent application Ser. No. 09/168,000, entitled Digital Rights Management System, filed on even date herewith both of which are assigned to the same assignee as the present application.
Referring first to FIG. 1, a distribution system 10 in accordance with the present invention can be better appreciated. A publisher server 100 contains thereon one or more files of protected information 105 such as the text of books, databases, code, graphics, or other information considered valuable by the owner. The files 105 are typically maintained in an unencrypted form on the publisher server 100 , although in some embodiments the files of content may be maintained in encrypted form. In other embodiments the publisher server 100 may include an encryption process for securing content files before such files are transmitted in the manner described hereinafter. Although it is to be understood that the certificate process described herein may be used with virtually any type of information, for purposes of example and simplification in the aid of understanding, the present invention will be described in the context of a text distribution system.
A user PC 110 , typically configured with Internet access and suitable front-end software 112 such as a Web browser (for example, NETSCAPE™ or MICROSOFT EXPLORER™, communicates with an electronic reader 115 as well as a retailer server 120 . As described in greater detail hereinafter, the reader 115 is typically identified by a unique indicia such as a serial number 117 and in a typical embodiment also includes a private encryption key 119 which may be uniquely associated with either a specific reader or a specific customer. In addition to the browser 112 , the user PC typically has installed application software such as a Java applet or a helper application 125 which cooperates with a browser by querying the reader 115 to extract the reader serial number or other customer ID 117 . The PC 110 may be rendered unnecessary in some embodiments by including in the reader 115 browser software and the ability to access the Internet. Alternatively, for some types of protected information, the functionality of the reader may be incorporated into a secure portion of a more generic device such as a PC.
The customer then browses a retailer's server 120 (for example, Amazon.com) and identifies selected books or text that the user wishes to purchase in electronic form. Once the customer begins the purchase transaction for the identified books (which typically includes providing ISBN numbers or other sufficient information to uniquely identify the book), the applet or helper application 125 provides the customer or reader specific indicia 117 to the retailer's server. Alternatively, this information can be entered manually, or could be stored as a cookie or on the server 120 . Still further, the helper application 125 could be implemented as a plug-in, although plug-ins tend to be browser-specific and more complicated as a result. Regardless of the specific implementation, the retailer's server 120 is supplied with customer-specific indicia which permits subsequent authentication of the purchase and verification of the purchaser. In some, though not all, the IP address of the user's PC may also be provided to the retailer server as part of the transaction. In addition, the user supplies appropriate payment information which may be, for example, a credit card number or other Internet-capable payment scheme.
The retailer server 120 , which may be any form of Internet-connected server, responds to a purchase request from a user by executing payment with an associated financial institution 130 such as a bank or other credit clearing house. In addition, the ID of the reader and the indicia of the requested publication (e.g., ISBN number) is supplied to an authentication server 135 . In a presently preferred embodiment, the authentication server 135 provides several key functions including maintenance of a database of the electronic IDs, or keys, of the various readers. Also, the server 135 maintains a database identifying the publisher for a given ISBN number, including country in which the customer's reader is located. In addition, the authentication server 135 authenticates requests from those readers by ensuring that the ID received as part of a particular transaction matches the user maintained in the database. Further, the authentication server maintains a database of all purchases and related accounting information for each of the readers. One advantage of such an arrangement is that, if a reader 115 fails or the content stored therein is erased, the database maintained by the server 135 can automatically arrange for replacement of the downloaded text in a manner described hereinafter. In addition, in at least some embodiments, the authentication server will execute a financial transaction with a bank 140 or other clearing house. The authentication server 135 typically passes to the publisher server 100 a confirmed request for a file 105 which represents the electronic version of the book requested by the user.
At this point the transaction is complete but for supplying the electronic file to the customer's reader. In some instances, the customer may not wish to immediately download the file; in others, the customer may want an immediate download. If no download is requested, the process essentially terminates until a download is requested. Once a download is requested—which may come hours, days, weeks or more later—the request is acknowledged by the publisher server 100 . At that point, the publisher server downloads the encrypted file 105 to the user's PC 110 , via the plug-in or helper application 125 ; a web browser may also be used in at least some embodiments. The encryption is typically customized for the electronic ID of the particular reader 115 , typically using the key or ID uniquely associated with that reader, so that the encrypted file can only be displayed as clear text on the requesting reader 115 . In addition, in a currently preferred embodiment, the user's PC is not capable of decrypting the file, so that no clear text version of the book exists anywhere but the publisher's server. In this manner, copyright violations are avoided and the rights of the publisher are protected. In some instances, such as for works in the public domain, it may be desirable not to use encryption, in which case the encryption/decryption steps are simply eliminated.
With the aid of the helper application 125 , the user's PC stores the encrypted file 105 until the associated reader 115 establishes a communications link through any suitable protocol, including serial, parallel, USB, twisted pair, or infrared. The file is then downloaded to the reader 115 , where appropriate decryption occurs and permits the file to be displayed as clear text.
In an important feature, the distribution scheme of the present invention never requires that the content represented by the file 105 be licensed to any intermediate holder; that is, neither the retailer server nor the authentication server need have any control over or custody of the content, which passes solely between the publisher server 100 (or the server of any other information owner) and the user PC 110 . In a presently preferred embodiment, the file 105 is maintained in encrypted form, although such encryption may not be required for all files 105 . Nevertheless, for those files that are encrypted, the publisher or other copyright holder can be assured that unauthorized copies will not exist. In some embodiments, it may also be desirable to configure the reader 115 to decrypt only a page of text currently being displayed, so that the remaining text is maintained in fully encrypted form even within the reader 115 .
Referring next to FIG. 2, an exemplary system and method for secure generation and installation of a key pair is shown in flow diagram form. The “factory equipment” portion 700 shown in dotted lines at the left of the diagram represents the functions performed by the manufacturing equipment; the “electronic reader” portion 705 shown at the right in FIG. 2 is performed at the reader level.
The process of FIG. 2 begins at step 710 with the generation of a public/private key pair for the specific device, or reader 115 . The process then advances to step 715 where the time/date, factory ID, and device external and internal serial numbers are appended to the key pair. At step 720 , a “Reg Ticket” is built that includes the Device Public Key, the date/time stamp, and the aforementioned serial numbers. That “Reg Ticket” is then encrypted at step 725 , using the Authentication Server Public Key. The “Reg Ticket” is then amended at step 730 by appending to it the Authentication Server Public Key. At step 735 , the amended Reg Ticket is then hashed and signed with the Factory Private Key to form a Device Certificate. The Device Certificate is then sent, at step 740 , to the “electronic reader” portion 705 , which in part of the reader 115 and the process advances to step 745 to await a response from the reader.
When the electronic reader 115 receives the Device Certificate at step 750 , it authenticates the Device Certificate using the Factory Public Key at step 755 . If the authentication fails, a security violation message is set at step 760 and the process halts. However, if the authentication succeeds, the actual serial number is compared with the Device Certificate internal serial number at step 765 . If the authentication fails, an error is set at 770 and the process halts. If, as will more often be the case, the authentication succeeds, the reader installs the device private key at step 775 . The reader thereafter installs the authentication server public key at step 780 , and at 785 stores the encrypted Reg Ticket for later uplink to an authentication server, after which the device is deemed ready to ship at step 790 . At that point the process sends a pass/fail status message back to the factory equipment, and the processes complete.
Thereafter, the reader 115 is provided to a user, and the user will at some point desire to acquire protected information viewable on the reader. At that point the user connects to the distribution system described in U.S. patent application Ser. No. 09/034,720 filed Mar. 4, 1998, incorporated herein by reference, via the Internet or other appropriate connection, and initiates a registration process on the first use. Thus, with reference to FIG. 3, the initiation of the registration process by the user is shown at step 800 . The process is then carried forward in the electronic reader 115 and the authentication server, with each portion shown in FIG. 3 respectively in dashed boxes 705 and 805 .
The process advances in the electronic reader portion 705 by the reader sending its Reg Ticket to an associated Certificate Authority at step 810 . The Certificate Authority may, in an exemplary embodiment, be the authentication server 135 , although it could be implemented in any convenient way. For purposes of clarity, the certificate authority in this case will be assumed to be the authentication server 135 . Upon receipt of the Reg Ticket from the reader in step 810 , at step 815 the authentication server authenticates the Reg Ticket, decrypts it using the authentication server private key and saves the Device Public Key. The authentication server then, at step 820 , sends to the reader a request for such user-specific information as specified by the certificate authority or other appropriate authority. This data can be entered directly with the authentication server over a Web interface. The reader replies (or the Web form is submitted) at step 825 once the user inputs the necessary data, after which the authentication server 805 verifies and saves the customer information at step 830 . At this point, step 835 , the authentication server creates a new public/private key pair for the User Certificate. The Public key is recorded in the Authentication Server database, and the private key is moved to a secure archive. The User Certificate contains information about the user, the private user key, and sequence number for this user. The Certificate is then encrypted using the Device Public Key and signed using the Certificate Authority Private Key. The User Certificate is then sent to the reader at step 840 .
Once the reader receives the User Certificate at step 845 , it is installed in the reader and the process advances to step 850 where the User Private Key is then decrypted, authenticated and installed. Whether the authentication and installation step is successful or not, the process advances to step 855 where the results are reported to the authentication server at step 860 . The server receives and stores the success/fail status, and the process completes at steps 865 and 870 , respectively, with the reader having an installed User Certificate and the authentication server portion of the process being done.
Referring next to FIGS. 4A-4B, the authentication steps in the registration process of FIG. 3 may be better appreciated. In particular, FIG. 4A, which occurs in the authentication server, shows the process of generating a User Certificate, while FIG. 4B, which occurs in the electronic reader, shows the process of authenticating the User Certificate received from the authentication server. The User Certificate is generated by, at step 900 , authenticating the Reg Ticket using the Factory Public Key. If the authentication is not successful, the process halts at step 905 . However, in the more common instance of the authentication succeeding, at step 910 the Reg Ticket is decrypted using the Certificate Authority Private Key. This provides the Device Public Key, which is saved to a database at step 915 .
At step 920 , the Public/Private Keys are generated for the User Certificate, and saved to a database. The User Certificate is then amended at step 925 by adding the time and date revision, a sequence number, a customer ID and a header. The resultant User Certificate is then encrypted at step 930 using the Device Public Key, with the encrypted result being signed by using the Authentication Server Private Key at step 935 . The User Certificate is then ready for sending to the reader, so the process completes at step 940 .
On the reader side, shown in FIG. 4B, step 850 (FIG. 3) of authenticating and installing the User Certificate begins at step 945 with the authentication of the User Certificate using the Authentication Server Public Key. If authentication fails, the process halts at step 950 ; but if successful, the process advances to step 955 and the User Certificate is decrypted using the Device Private Key. At step 960 a check is performed to determine whether the sequence number portion of the user certificate is greater than an existing user certificate (if any—in new registrations there will not be an existing certificate). If the sequence number is not greater, the process fails at step 965 .
In most instances, as discussed hereinafter in connection with FIGS. 5 and 6, the sequence number will be greater and the process will advance to step 965 . At that step the reader install the User Public Key and Customer information, uniquely associating that reader with a particular user. The process then completes at step 970 .
At this point, the user is free to acquire protected information and view it in any permissible manner, all as described in U.S. patent application Ser. No. 09/034,720, discussed above. However, at future time a user may lose a reader or simply desire to upgrade to a newer model. At that time, the typical user is likely to have a substantial investment in the digital rights to the protected information, and is unlikely to want to incur any significant costs in having to reacquire those rights. At the same time, the owner of the protected information needs assurances that the rights will not be abused, while the operator of the authentication server needs a simple method by which rights can be appropriately transferred to a new reader.
These concerns are met by the certificate move process shown in FIGS. 5 and 6, which provide for movement of a certificate and the associated keys from a first device to a second device. In a typical scenario, the user receives a second device and desires to transfer his rights from the first device to the second device, and initiates the process by linking to the distribution system and more particularly to the authentication server, as shown at step 1010 of FIG. 5 . The authentication server responds at step 1015 by developing a revocation certificate to be sent to the first reader, which is then sent at step 1020 . The first device, if available, responds at step 1025 by revoking that reader's User Certificate, and sends back confirmation to the authentication server. In the event the first reader is lost or stolen, and therefore unavailable, the step 1025 may be held for later implementation in the event the reader does attempt to make contact at some point. For purposes of clarity, however, it will be assumed in this example that both devices are available.
At step 1030 , the authentication server receives confirmation of the revocation which occurred at step 1025 , and at step 1035 the authentication server generates a new User Certificate with the old public and private keys, but with a higher sequence number. The process then advances to step 1040 where the new User Certificate is sent to the second device/reader. The new certificate is then installed in the second device at step 1045 and confirmation is returned to the server. The server receives the confirmation at step 1050 , and completes with the second device being fully authorized to view any of the titles or other information acquired by the user of the first device. Simply put, the User certificate and associated public and private keys has been moved from the first device to the second device.
Referring next to FIG. 6, however, details of steps 1015 through 1030 shown generally in FIG. 5 —the revocation steps—may be better appreciated. As shown generally in FIG. 5, the subprocess begins with the user initiating key movement from the first to the second device at step 1010 . This causes, at step 1110 , the authentication server to create and save a Revocation Token of random numbers. Although random numbers are generally preferred for security reasons, non-random numbers or other indicia may be acceptable in some embodiments. The Revocation Token is then encrypted at step 1105 using the Authentication Server Private Key, after which the result is encrypted using the Device Public Key at step 1110 . The double encrypted result is then signed at step 1115 with the Authentication Server Private Key and sent (at step 1120 ) to the first device as a Revocation Certificate.
The first device, assuming it is available, receives the Revocation Certificate at step 1125 , which it attempts to authenticate at step 1130 . If the authentication fails, the process halts at step 1135 . However, if successful, the process advances to step 1140 where the Revocation Token is decrypted from the Revocation Certificate using the Device Private Key. A revocation acknowledge token is then sent to the Authentication Server at step 1145 .
The authentication server receives the acknowledge token and decrypts it using the Authentication Server Private Key, and compares the result to the saved to the authentication server. In the event the first reader is lost or stolen, and therefore unavailable, the step 1025 may be held for later implementation in the event the reader does attempt to make contact at some point. For purposes of clarity, however, it will be assumed in this example that both devices are available.
At step 1030 , the authentication server receives confirmation of the revocation which occurred at step 1025 , and at step 1035 the authentication server generates a new User Certificate with the old public and private keys, but with a higher sequence number. The process then advances to step 1040 where the new User Certificate is sent to the second device/reader. The new certificate is then installed in the second device at step 1045 and confirmation is returned to the server. The server receives the confirmation at step 1050 , and completes with the second device being fully authorized to view any of the titles or other information acquired by the user of the first device. Simply put, the User certificate and associated public and private keys has been moved from the first device to the second device.
Referring next to FIG. 6, however, details of steps 1015 through 1030 shown generally in FIG. 5 —the revocation steps—may be better appreciated. As shown generally in FIG. 5, the subprocess begins with the user initiating key movement from the first to the second device at step 1010 . This causes, at step 1110 , the authentication server to create and save a Revocation Token of random numbers. Although random numbers are generally preferred for security reasons, non-random numbers or other indicia may be acceptable in some embodiments. The Revocation Token is then encrypted at step 1105 using the Authentication Server Private Key, after which the result is encrypted using the Device Public Key at step 1110 . The double encrypted result is then signed at step 1115 with the Authentication Server Private Key and sent (at step 1120 ) to the first device as a Revocation Certificate.
The first device, assuming it is available, receives the Revocation Certificate at step 1125 , which it attempts to authenticate at step 1130 . If the authentication fails, the process halts at step 1135 . However, if successful, the process advances to step 1140 where the Revocation Token is decrypted from the Revocation Certificate using the Device Private Key. A revocation acknowledge token is then sent to the Authentication Server at step 1145 .
The authentication server receives the acknowledge token and decrypts it using the Authentication Server Private Key, and compares the result to the saved token number at step 1160 . If the token does not match, the process halts at step 1165 ; but if a match exists, the revocation is deemed a success and is recorded in a database. At that point the step can advance to generating a new user certificate, as shown at step 1035 in FIG. 5 .
It can thus be appreciated that an effective method for secure generation of public and private keys has been shown, together with a method for transferring those keys and the associated rights. Having fully described a preferred embodiment of the invention and various alternatives, those skilled in the art will recognize, given the teachings herein, that numerous alternatives and equivalents exist which do not depart from the invention. It is therefore intended that the invention not be limited by the foregoing description, but only by the appended claims. | A delivery system for managing security keys uses three key pairs to establish, register, move and revoke rights in a device to view protected information. The first and second key pairs cooperate to establish a secure certificate containing a device public and private key, and the pairs of keys are manipulated to install the appropriate keys in the device and the associated authentication server without ever exposing the keys. Thereafter, in the event of a need to authorize a new device to view content associated with a prior, authorized device, the key pairs are used to revoke the rights of an old device and establish identical viewing rights in the new device. | 6 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to self-defense devices, and specifically to self-defense flashlights.
2. Description of the Prior Art
Pen lights have been described for several decades with the earliest documents dating back to the early 1920's. Several inventions described pen-shaped lights with or without a writing instrument. However, none of these documents appear to describe the further function of the device as an instrument for self-defense. Devices combining a pen light with other applications such as USB drives, pen fans, projectors, barcode readers and scanners also exist. Inventions relating to pen-shaped laser pointers, pen-shaped styluses, and pen-shaped devices using infra-red for input to computers also exist. Other inventions describe portable lights or flash lights combined with stun guns, marksmen trainers and knives to be used as weapons.
U.S. Pat. No. 5,673,996 for “Pen with LED Indicator” describes a pen which includes a light assembly comprising of a lamp, battery and a switch in the upper portion of the barrel. The invention further includes a switch-on and off position to control the LED lamp.
U.S. Publication 2010/0104350 for “LED Luminous Pen” describes a LED luminous pen comprising of a pen-core, battery, circuit board and a LED with the battery in the upper portion of the penholder and the LED in the lower portion of the penholder. The invention further includes a rotary assembly comprising of a metallic connecting casing.
U.S. Publication 2006/0285317 for “Pen with Light Source” describes a pen with light source comprising a case with press-on turning device and a lower case containing a pen-refill. The invention further describes a lighting device inserted inside the upper and lower cases. The lighting device comprises of a battery socket, batteries, a lamp socket and a lamp.
U.S. Pat. No. 6,161,936 for “Portable Lighting Device” describes a pen-type portable lighting device with a battery casing and a miniature lamp holder near the end of the battery casing. The invention further describes a miniature lamp mounted on the lamp holder which surrounds the light emitting portion.
U.S. Pat. No. 6,948,827 for “LED Flashlight Construction” describes an LED flashlight construction comprising of a molded plastic housing. The invention further includes a hollow tubular section comprising of a semi-cylindrical tube with a connected battery chamber. The device may also be pen-shaped.
SUMMARY OF THE INVENTION
The present invention relates to self-defense devices.
It is an object of this invention to provide a self-defense light source.
Yet another object of this invention to provide to provide a self-defense light source with a tissue sampler.
A further object of this invention is to provide a self-defense light source with a tissue sampler and a writing instrument.
Accordingly, a broad embodiment of this invention is directed to a flashlight with a weapon end, tissue-abrading features, and a writing instrument.
These and other aspects of the present invention will become apparent to those skilled in the art after a reading of the following description of the preferred embodiment when considered with the drawings, as they support the claimed invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a drawing of one embodiment of the invention.
FIG. 2 is an exploded drawing of the embodiment of FIG. 1 .
FIG. 3 is a close-up drawing of the tip of an embodiment of the invention.
FIG. 4 show example embodiments A and B of the invention.
DETAILED DESCRIPTION
U.S. Provisional Application 61/414,203 and U.S. application Ser. No. 13/296,657 are hereby incorporated by reference in their entirety.
Referring now to the drawings in general, the illustrations are for the purpose of describing a preferred embodiment of the invention and are not intended to limit the invention thereto.
The present invention provides for a generally tubular-shaped, multifunctional self-defense device, generally described as 100 in FIG. 1 . The multifunctional self-defense device includes a blunt end 10 and a sharp end 20 . The device is designed to be used as a self-defense striking object. As such, the device is designed to be gripped and preferably contains one or more non-slip sections 30 to prevent slipping when striking. The device is also preferably made from hard, impact-resistant material that can be used to break glass and is also preferably lightweight for ease of carrying. For example, the tubular shape is preferably composed of aluminum, titanium or similar materials. More preferably, the tubular shape is composed of anodized aircraft aluminum or any similar strong material.
The device is composed of first section 40 and a second section 50 that are joined together. The two sections preferably are threaded to screw together. As shown in FIG. 2 , the blunt section 40 is further separable to permit the exchange of a battery 60 contained inside the device and the two sections preferably screw together to turn a light on and off. Alternatively, a switch (not shown) can be used to activate the light. The two sections are generally described as a blunt section 40 and a sharp section 50 .
The two sections preferably can operate independently of each other. For example, if the blunt section contains a light and the sharp section contains a pen, once the parts are separated the light can still be operated and the sharp section can still be used as a pen or a self-defense weapon. In these cases, the switch to operate the light is completely incorporated in the blunt section. Thus, the device is operable to provide lighting to the user when the user is using the writing device.
The blunt section 40 contains a light source 90 configured so that the device functions as a flashlight. Preferably, the light is a light-emitting diode (LED). As such, the light contained in the blunt section is recessed and/or the blunt end has a lens (not shown) and/or a shield 110 protecting the light. Preferably, blunt end is designed and configured so that the light emitted is not visible laterally. For example, a protective shield xx is solid, rather than perforated.
The blunt section further includes sections housing electronic circuit boards 92 and 94 for controlling an LED light.
All the sections are preferably threaded together. The sections that do not need to be opened or manipulated by a user are preferably locked together using a threadlocking adhesive, such as Loctite adhesives.
The end of the blunt section is smooth to prevent a user from hurting his/her thumb or other digit that is holding the end while striking an object with the device.
The pointed section of the device is pointed such that it will puncture tissue and clothing when struck against these. The pointed section includes large grooves 160 , shown in FIG. 3 , herein called “blood channels”, to facilitate bleeding upon stabbing.
The pointed section preferably includes a bulbous feature 170 to facilitate bleeding upon stabbing. The bulbous feature 170 is generally shaped like a spear tip or arrowhead.
The pointed section preferably includes tissue-capturing elements for obtaining tissues samples for biological identification. The pointed section preferably includes barbs 180 to capture tissue from an assailant when the sharp end of the device penetrates the assailant's tissue. Deep, narrow grooves 200 are preferably included in the pointed section. The grooves are sufficiently deep and narrow such that they are difficult to clean by merely rinsing and wiping. Thus, the deep narrow grooves make it difficult for an assailant to quickly clean away any tissue samples collected on the device.
The tubular shape preferably includes a writing device 210 , such as an ink pen cartridge, that extends from the internal end of the pointed section. The ink pen cartridge is enclosed to prevent damage when the pointed section is being used for self-defense or otherwise to strike an object. Refill pen cartridges are also contained within the pointed section of the pen. In another embodiment (not shown), the pen is reversed, extending out the pointed end, and retractable.
The pointed section also preferably includes threads (not shown), such that accessory devices can be mounted on the flashlight. For example, a firestarter, knife sharpener, hammer head, wrench, and any tool that needs a handle can be mounted on the device. Different sizes of the present invention are possible, as shown in FIG. 4 . Smaller versions of the present invention, shown as embodiment A, use a single battery 220 and are sized such that they can be attached to a key chain and not cause an inconvenience. A larger version, shown in embodiment B, uses a larger battery or multiple batteries and is sized more as a writing instrument.
Certain modifications and improvements will occur to those skilled in the art upon a reading of the foregoing description. The above-mentioned examples are provided to serve the purpose of clarifying the aspects of the invention and it will be apparent to one skilled in the art that they do not serve to limit the scope of the invention. All modifications and improvements have been deleted herein for the sake of conciseness and readability but are properly within the scope of the present invention. | A self-defense device that includes a flashlight with a weapon end, tissue-abrading and tissue-collecting features, and with or without a writing instrument. | 5 |
This is a continuation of application Ser. No. 07/069,040 filed 07/01/87, now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to irradiated polypropylene articles, such as fibers, films, and nonwoven fabrics and to a method for preparing such articles.
2. Background Information
Polypropylene is often a material of choice for articles such as fiber, films and molded articles due to its various properties such as non-toxicity and inertness as well as its low cost and the ease with which it can be extruded, molded, and formed into articles. It is often desirable to graft-polymerize monomers onto polypropylene substrates using ionizing radiation, e.g., electron beam radiation, to provide such properties as hydrophilicity, hydrophobicity, increased adhesion to adhesives, surfaces on which secondary reactions can occur, and ion exchange capacity. However, polypropylene treated with ionizing radiation is subject to degradation, e.g., embrittlement, discoloration, and thermal sensitivity, during or subsequent to irradiation.
The addition of various stabilizers, e.g., antioxidants, to the polypropylene material has been suggested to prevent discoloration and degradation.
U.S. Pat. No. 4,110,185 (Williams et al.) discloses irradiation sterilized articles of polypropylene which have incorporated therein a mobilizer which increases the free volume of the polymer and, therefore, lowers the density of the polymer. Suitable mobilizers mentioned include hydrocarbon oils, halogenated hydrocarbon oils, phthalic ester oils, vegetable oils, silicone oils, and polymer greases.
U.S. Pat. No. 4,113,595 (Hagiwara et al.) discloses irradiated crosslinked polyolefin molded products of a blend of polyolefin, a compound having acetylenic linkage, and an aromatic hydrocarbon-substituted organic amine or an aromatic secondary amino compound.
U.S. Pat. Nos. 4,274,932 and 4,467,065 (Williams et al.) disclose polypropylene stabilized for irradiation sterilization. The polypropylene has a narrow molecular weight distribution and has incorporated therein a mobilizer, as used in U.S. Pat. No. 4,110,185, described hereinabove.
U.S. Pat. No. 4,432,497 (Rekers) discloses radiation-stable polyolefin compositions containing a benzhydrol or benzhydrol derivative stabilizer.
U.S. Pat. No. 4,460,445 (Rekers) discloses radiation-stable polyolefin compositions containing a hindered phenolic stabilizer and a benzaldehyde acetal stabilizer.
European Patent Application No. 0,068,555 (Lenzi) discloses irradiation-sterilizable polypropylene articles, the polypropylene having one to eight weight percent low density polyethylene added thereto.
U.S. Pat. No. 3,987,001 (Wedel et al.) discloses an ultraviolet protectorant composition for surface application by aerosol to polyolefins, which composition contains a 2-hydroxy benzophenone and benzoate ester ultraviolet protectorant, a polymethacrylate binder, a solvent, and propellant.
Although the addition of the various stabilizers to polypropylene serves to diminish degradation by radiation, the use of additives increases costs, some additives may pose toxicological problems when contacted with pharmaceuticals, and some additives may adversely affect the physical properties of the polypropylene. Also, when the polypropylene is subjected to high temperatures during processing, e.g., such as occurs during blown microfiber web extrusion, the additives, especially antioxidants, are often destroyed, i.e., decomposed. The present invention overcomes these problems without addition of radiation stabilizing additives as required in the afore-mentioned Williams et al. '185, '932, and '065, Hagiwara et al. '595, Rekers '497 and '445, Lenzi '555, and Wedel '001 patents, and provides low cost polypropylene articles having graft-polymerized monomers thereon and a method for preparing irradiated polypropylene articles, with the articles retaining useful tensile properties even after prolonged storage periods.
SUMMARY OF THE INVENTION
The present invention provides polypropylene articles of non-crystalline mesomorphous polypropylene, which polypropylene need not contain radiation stabilizing additives, and the polypropylene having olefinic unsaturation-containing monomers graft-polymerized thereon by ionizing radiation in a dosage sufficient to degrade crystalline polypropylene. The irradiated articles such as films retain useful tensile properties after storage periods of as long as at least four months. For example, films of the invention generally retain an elongation at break of at least 200 percent, preferably at least 300 percent, after irradiation, and blown microfiber webs of the elongation at break that they exhibited prior to irradiation. Blown microfiber webs generally retain a modulus of resilience of at least about 20 N-m/cm 3 , preferably 30 N-m/cm 3 .
The invention further provides a method for preparing irradiated polypropylene articles, the steps of which include: extruding polypropylene, which polypropylene need not contain radiation stabilizing additives; quenching the extruded polypropylene immediately after extrusion to provide non-crystalline mesomorphous polypropylene; coating at least a portion of the surface of non-crystalline mesomorphous polypropylene with an ionizing radiation graft-polymerizable monomer; and irradiating the non-crystalline mesomorphous polypropylene with a dosage of ionizing radiation that would degrade crystalline polypropylene and is sufficient to effect graft-polymerization of the monomer. The irradiated articles, after six months storage, are substantially undegraded.
Although non-crystalline, mesomorphous polypropylene is known (Natta, G., et al. Structure and Properties of Isotactic Polypropylene, Del Nuovo Cimento, Supplemento Al, Volume XV, Serie X, N.1, 1960, pp. 40-51) the present invention for the first time, insofar as known, applies a dose of ionizing radiation to non-crystalline, mesomorphous polypropylene to achieve non-degraded polypropylene products having monomer graft-polymerized thereto or a coating cured in situ thereon. In fact, it has been thought that crystalline regions in polypropylene provide oxygen-impermeable regions which limit the extent of oxidation and reduce the maximum oxidation rate, and that readily-accessible amorphous regions were preferentially attacked (Pimer, S. H., ed., Weathering and Degradation of Plastics, Gordon and Breach, Science Publishers Inc., New York, 1966, pp. 104-107).
It is suspected that the radiation stability of the non-crystalline mesomorphous polypropylene is related to control of the morphology. The non-crystalline mesomorphous polypropylene has been described as a non-spherulitic structure by P. H. Geil (Polymer Single Crystals, Interscience, N.Y., 1963, p. 270). Crystalline polypropylene may have "chain-folds", i.e., crystalline/amorphous folds, in the structure which provide areas for radical attack because of their higher energy. In contrast, the non-crystalline mesomorphous structure is believed to have ordering as in a Fringed Micelle model with no chain-fold defects. It is suspected that this lack of chain fold defects minimizes the number of sites for radical attack and thereby provides the resistance to radiation degradation.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is the X-ray diffraction pattern of the non-crystalline mesomorphous polypropylene film of Example 1.
FIG. 2 is the X-ray diffraction pattern of the crystalline polypropylene film of Comparative Example 2.
FIG. 3 is a photograph of water soluble ink applied to the surface of the film of Example 1 prior to graft polymerization.
FIG. 4 is a photograph of water soluble ink applied to the surface of the film of Example 1 after graft polymerization.
FIG. 5 is the X-ray diffraction pattern of the non-crystalline mesomorphous polypropylene blown microfiber web of Example 7.
FIG. 6 is the X-ray diffraction pattern of the crystalline polypropylene blown microfiber web of Comparative Example C9.
DETAILED DESCRIPTION OF THE INVENTION
Polypropylene to be used in products of the invention can be extruded from polymer melt in any shape which can be rapidly cooled throughout after extrusion to obtain non-crystalline mesomorphous polypropylene. The shape and/or thickness of the extruded material will be dependent on the efficiency of the quenching systems utilized. Generally, films, fibers, and blown microfiber webs are the preferred extruded materials. The extruded polypropylene should not be subjected to any treatment at temperatures above about 140° F. (60° C.), such as annealing, orientation, or stretching, prior to irradiation as such treatment can change the non-crystalline mesomorphous polypropylene structure to a predominantely crystalline structure. After irradiation, the polypropylene can be annealed, stretched, or oriented, if properties provided by such treatments are desired.
The polypropylene may contain conventional additives such as antistatic materials, dyes, plasticizers, ultraviolet absorbers, nucleating agents, surfactants, and the like. The amount of additives is typically less than ten weight percent of the polymer component, preferably less than two percent by weight.
To obtain the non-crystalline mesomorphous phase polypropylene, the extruded material must be quenched immediately after extrusion before the material reaches the crystalline state. The presence of the non-crystalline mesomorphous phase polypropylene can be confirmed by X-ray diffraction. FIGS. 1 and 5 are X-ray diffraction patterns for mesomorphous polypropylene and FIGS. 2 and 6 are X-ray diffraction patterns for crystalline polypropylene. Although the term "non-crystalline mesomorphous" or "mesomorphous" is used to describe the polypropylene useful in the present invention, the material contains some crystalline phase polypropylene as determined by density measurements using a gradient column. Generally, the percent crystallinity of the non-crystalline mesomorphous polypropylene is below about 45 percent.
Various known methods of quenching can be used to obtain the non-crystalline mesomorphous structure including plunging the extruded material into a cold liquid, e.g., ice water bath, spraying the extruded material with a liquid such as water, and/or running the extruded material over a cooled roll or drum.
Extruded polypropylene film is preferably quenched by contact with a quench roll or by plunging the film into a quench bath, such as an ice-water bath as disclosed by R. L. Miller ("On the Existence of Near-range Order in Isotactic Polypropylenes", Polymer, 1, 135 (1960). Where a quench roll is used, the roll temperature is preferably maintained at a temperature below about 75° F. (24° C.) and the film is generally in contact with the roll until solidified. The quench roll should be positioned relatively close to the extruder die, the distance being dependent on the roll temperature, the extrusion rate, the film thickness, and the roll speed. Generally, the distance from the die to the roll is about 0.1 in (0.25 cm) to 2 in (5 cm). Where a quench bath is used, the bath temperature is preferably maintained at a temperature below about 40° F. (40° C.). The bath should be positioned relatively close to the die, generally about 0.1 in (0.25 cm) to 5 in (13 cm) from the die to the bath.
Polypropylene melt blown microfibers are produced by extruding molten polymer through a die into a high velocity hot air stream to produce fibers having an average fiber diameter of less than about 10 microns. The fibers are generally collected on a drum in the form of a web. The preparation of microfiber webs is described in Report No. 4364 of the Naval Research Laboratories, published May 25, 1954, entitled "Manufacture of Superfine Organic Fibers," by Wente, Van A. et al. and in Wente, Van A., "Superfine Thermoplastic Fibers" in Industrial Engineering Chemistry, Vol. 48, No. 8, August, 1956, pp. 1342-1346.
To achieve non-crystalline, mesomorphous polypropylene webs, the blown microfiber web is preferably quenched by spraying with a liquid such as water or by cooling the collector drum onto which the microfiber web is collected. Optimum quenching can be achieved by spraying the fiber web near the die, then collecting the web on a cooled drum. The water spray is preferably at a temperature of less than about 50° F. (10° C.) and less than about 1 inch (2.5 cm) from the die and the collector drum is preferably about 2 in (5 cm) to 4 in (10 cm) from the die, but can be as much as 8 in (20 cm) to 10 in (25 cm) depending on extrusion rates.
The non-crystalline mesomorphous phase polypropylene can have graft-polymerized thereto monomers which are commonly used to modify surface characteristics of polyolefin substrates such as those described in Hsiue et al., Preirradiation Grafting of Acrylic and Methacrylic Acid onto Polyethylene Films:Preparation and Properties. J. of Applied Polymer Science, 30, 1023-×(1985) and Shkolnik et al., Radiation-Induced Grafting of Sulfonates On Polyethylene. J. of Applied Polymer Science, 27, 2189-2196 (1982) and U.S Pat. No. 3,634,218 (Gotohda) which are incorporated herein by reference for that purpose. For example, adhesion promoting primers such as N,N-dimethylacrylamide, glycidyl acrylate and diisopropylacrylamide for use with acrylate adhesives, glycidyl acrylate, trimethylolpropane triacrylate, and hydroxyethyl acrylate for use with epoxy adhesives, and N,N-dimethylaminoethylacrylate, N-vinyl-2-pyrrolidone and 2-vinyl-pyridine for use with cyanoacrylate adhesives can be graft-polymerized onto the surface of the non-crystalline mesomorphous phase polypropylene. Monomers which provide hydrophilicity to the surface of the polypropylene substrate such as acrylic acid, N-vinyl-2-pyrrolidone and sulfoethyl methacrylate can be graft-polymerized onto the polypropylene substrate.
The following non-limiting examples are provided to further illustrate the invention. In these examples, the following tests were used to characterize the polypropylene films and microfiber webs:
Tensile properties (film): Samples of film 1/2 in (1.25 cm) wide were tested for yield stress and elongation at break using an Instron™ model no. 1122 at a gauge length of 2 in (5 cm) and a crosshead speed of 2 in/min (5 cm/min).
Tensile properties (microfiber web) One-inch wide samples were tested for energy required to stretch to yield point using an Instron™ model no. 1122 at a gauge length of 0.08 in (2 mm), a crosshead speed of 2 in/min (5 cm/min), chart speed of 50 in/min (125 cm/min), and full scale of 2 kg. The modulus of resilience is calculated as described in Higdon, A., Mechanics of Materials, John Wiley & Sons, Inc., N.Y., 1976, pgs 104-106.
180° Peel adhesion:
A 2.5 cm wide, 20.3 cm long strip of pressure-sensitive adhesive tape (Scotch™ brand tape no. is adhered to a 10.1 cm wide, 15.2 cm long sheet of test substrate with a free end of the tape extending beyond the end of the test substrate. The sample is rolled twice with a 1.35 kg hard rubber roller to ensure contact between the adhesive and the test substrate. The sample is aged at room temperature (22° C.) for 24 hours. The free end of the tape is removed from the text substrate at a rate of 6 inches/minute using a Slip/Peel Tester, available from Instrumentors, Inc.
EXAMPLE 1 AND COMPARATIVE EXAMPLE C1
Polypropylene films were prepared from Cosden 8670 polypropylene polymer (melt flow index 4; average molecular weight, by GPC-204,000) using a 11/4 in (3.2 cm) Brabender™ extruder with a 12 in (30.5 cm) wide film die at a thickness of about 1.5 mil (0.04 mm) under the following conditions:
______________________________________Melt temperature (°C.) 206Screw speed (rpm) 47Polymer flow rate (kg/hr) 4.7Die temerature (°C.) 204______________________________________
The films were extruded onto a chrome-plated 3 in (7.6 cm) diameter casting roll spaced one-inch (2.5 cm) from the die. The film was in contact with the roll for about 2.5 seconds The roll was maintained at 44° F. (6.7° C.) and 150° F. (65.5° C.) to provide non-crystalline mesomorphous film (Example 1) and crystalline film (Comparative Example 1), respectively.
Each film was coated with a solution containing 99.9 weight percent acrylic acid and 0.1 weight percent wetting agent (FC-430, available from 3M Company). The films were irradiated using an electron beam at a dosage of 5 Mrad in an inert (nitrogen) atmosphere to effect graft polymerization of the acrylic acid onto the polypropylene films. Control films without the acrylic acid coating were also exposed to 5 Mrad electron beam irradiation. Non-irradiated, graft-polymerized, and control films were tested for yield stress and elongation at break after 4 months storage at 70° F. (21° C.). The results are shown in Table I.
TABLE I______________________________________ Yield Stress Elongation (kg/cm.sup.2) at break (%)______________________________________Example 1Non-irradiated 160 730Irradiated/acrylic acid graft 134 660Irradiated/no graft 151 640Comparative Example 1Non-irradiated 229 880Irradiated/acrylic acid graft 250 280Irradiated/no graft 223 520______________________________________
The data in Table I shows that the non-crystalline mesomorphous film of Example 1 loses very little elongation at break (9.6%) after graft polymerization and storage, while the crystalline film of Comparative Example 1 exhibits a significant loss in elongation at break (68%) after graft polymerization and storage.
Samples of the film of Example 1 before and after graft polymerization of the acrylic acid on the surface of the film were tested for hydrophilicity by applying a water-based ink on the film. FIG. 3 shows the lack of hydrophilicity of the film prior to graft polymerization of the acrylic acid as evidenced by the beads of ink formed on the surface of the film. FIG. 4 shows the hydrophilicity of the film after graft polymerization of the acrylic acid as evidenced by the sharp lines of ink on the film surface.
EXAMPLES 2-4 AND COMPARATIVE EXAMPLES C2-C6
Polypropylene films were extruded and quenched as in Example 1 and Comparative Example 1 to provide non-crystalline mesomorphous polypropylene film (Examples 2-4 and Comparative Example C2) and crystalline polypropylene film (Comparative Examples C3-C6). The films of Examples 2-4 and Comparative Examples C4-C6 were coated with a solution containing 99.9 weight percent N,N-dimethylacrylamide and 0.1 weight percent FC-430 wetting agent. The N,N-dimethylacrylamide was grafted to the films using electron beam radiation at a dose of 0.5, 2, and 5 Mrad. Comparative Examples C2 and C3 were untreated. The films were tested for 180° peel adhesion when prepared (initial) and after 2 years storage at 70° F. (21° C.) with the results set forth in Table III. The tensile properties of the untreated films and those treated with 5 Mrad dose were tested when prepared (initial) and after 4 months and 2 years storage at 70° F. (21° C.) with the results set forth in Table IV.
TABLE III______________________________________ Peel adhesion (g/cm)Example Dose (Mrad) Initial 2 Years______________________________________C2 0 102 1432 0.5 169 2043 2 377 3924 5 384 375C3 0 127 163C4 0.5 150 225C5 2 257 380C6 5 392 484______________________________________
TABLE IV______________________________________ Yield stress ElongationExample Dose (Mrad) Time (kg/cm.sup.2) at break (%)______________________________________C2 0 Initial 164 700C2 0 4 mo 154 655C2 0 2 yr 172 6204 5 Initial 164 7004 5 4 mo 161 6304 5 2 yr 181 610C3 0 Initial 241 800C3 0 4 mo 252 750C3 0 2 yr 266 620C6 5 Initial 241 800C6 5 4 mo 246 255C6 5 2 yr * *______________________________________ *too brittle to test
As can be seen from the peel adhesion values in Table III, enhanced peel adhesion results from the grafting of the N,N-dimethylacrylamide on the polypropylene films with higher peel adhesion values resulting from higher doses of radiation. The data in Table IV shows that the crystalline irradiated film, Comparative Example C6, has a significant loss in elongation at break after 4 months storage and is too brittle to test after 2 years storage, while the irradiated mesomorphous- polypropylene, Example 4; substantially retains its ability to elongate under stress even after a 2-year storage period.
EXAMPLE 5 AND COMPARATIVE EXAMPLE C7
Polypropylene films were extruded and quenched as in Example 1 and Comparative Example C1 to provide non-crystalline mesomorphous polypropylene film (Example 7) and crystalline polypropylene film (Comparative Example C7). Each film was coated with a solution containing 90 weight percent N-vinyl-2-pyrrolidone, 9.9 weight percent trimethylolpropane triacrylate, and 0.1 weight percent FC-430 wetting agent. The N-vinyl-2-pyrrolidone and trimethylolpropane triacrylate were grafted to the films using 5 Mrad electron beam radiation. Grafting was confirmed by iodine uptake. After a period of 1 year, the film of Comparative Example C7 had become brittle and had reduced elongation while the film of Example 5 substantially retained its tensile properties.
EXAMPLE 6 AND COMPARATIVE EXAMPLE C8
Polypropylene films were extruded and quenched as in Example 1 and Comparative Example C1 except that the polypropylene used was Exxon polypropylene 3014 (melt flow index - 12; average molecular weight, by GPC - 161,000) to provide non-crystalline mesomorphous polypropylene film (Example 6) and crystalline polypropylene film (Comparative Example C8). Each film was treated with a solution containing 90 weight percent N-vinyl-2-pyrrolidone, 9.9 weight percent trimethylolpropane triacrylate, and 0.1 weight percent FC-430 wetting agent. The N-vinyl-2-pyrrolidone and trimethylolpropane triacrylate were grafted to the films using 5 Mrad electron beam radiation. Grafting was confirmed by iodine uptake. After a period of one year, the film of Comparative Example C8 had become brittle with reduced elongation, while the film of Example 5 substantially retained its tensile properties.
EXAMPLE 7-9 AND COMPARATIVE EXAMPLES C9-C12
Melt blown polypropylene microfiber webs having a weight of 50 g/m 2 were extruded, as described in Wente, Van A., "Superfine Thermoplastic Fibers", supra, using Escorene PP 3085 polypropylene polymer (available from Exxon Chemical Americas.) The fiber diameter in the webs was about 5 microns. The extruder conditions were:
______________________________________Polymer rate (kg/hr/die inch) 0.45Polymer melt temperature (°C.) 388Air temperature (°C.) 382Air pressure (kPa) 55______________________________________
The webs of Examples 7-9 were quenched with water at a temperature of 40° F. (4° C.) and at a rate of 5 gal/hr (19 1/hr) with the spray located 6 inches (15 cm) above the die and directed at the fibers as they exited the die.
The quenched web of Example 7 was analyzed by wide angle X-ray diffraction as shown in FIG. 5 and found to be non-crystalline mesomorphous in structure.
The webs of Comparative Example C9-C12 were not quenched, producing crystalline polypropylene webs. The unquenched web of Comparative Example C9 was analyzed by wide angle X-ray diffraction as shown in FIG. 6, confirming the crystalline structure of the fibers in the web.
The webs of Examples 7-9 and Comparative Examples C10-C12 were treated with a solution containing 15 weight percent acrylic acid, 5 weight percent dichloroethane and 80 weight percent ethyl alcohol to achieve about 10 weight percent solution on the webs. The acrylic acid was grafted to the polypropylene by electron beam radiation at the dose set forth in Table V. The webs were evaluated for energy to stretch to the yield point after two weeks, four weeks, and four months. The results are set forth in Table V.
TABLE V______________________________________ Energy (N-m/cm.sup.3)Example (Mrad) 2 week 4 week 4 mo______________________________________7 1 0.94 0.77 0.488 2 0.85 0.64 0.429 5 0.50 0.39 0.22C9 0 0.43 0.37 0.34C10 1 0.37 0.51 0.28C11 2 0.21 0.28 0.11C12 5 0.10 0.10 0.04______________________________________
As can be seen from the data in Table V, the energy required to stretch the microfiber webs of Comparative Examples C11 and C12 had substantially decreased after four months storage, with the webs of Comparative Examples C11 and C12 not retaining useful tensile properties as evidence by the energy required to stretch the webs to their yield points of 0.11 N-m/cm 3 and 0.04 N-m/cm 3 , respectively. The microfiber webs of Examples 7-9 retained sufficient useful strength after four months storage as evidenced by the energy required to the webs to their yield points of 0.47 N-m/cm 3 , 0.42 N-m/cm 3 , and 0.22 N-m/cm 3 , respectively. | Polypropylene articles are provided. The polypropylene articles comprise non-crystalline mesomorphous polypropylene having olefinic unsaturation-containing monomers graft-polymerized thereon by ionizing radiation in a dosage sufficient to degrade crystalline polypropylene. The irradiated polypropylene articles retain useful tensile properties after storage periods of as long as at least about four months. Further provided is a method for preparing irradiated polypropylene articles having olefinic unsaturation-containing monomers graft-polymerized thereon comprising the steps of melt extruding polypropylene; quenching the extruded polypropylene immediately after extrusion to provide non-crystalline mesomorphous polypropylene; coating the non-crystalline mesomorphous polypropylene with an ionizing radiation graft-polymerizable monomer; and irradiating the coated non-crystalline mesomorphous polypropylene with a dosage of ionizing radiation sufficient to degrade crystalline polypropylene and sufficient to effect graft-polymerization of the monomer onto the surface of the polypropylene. | 3 |
FIELD
[0001] Embodiments of the invention relate to the treatment of pain, including neuropathic pain, in mammals.
BACKGROUND
Neuropathic Pain
[0002] Pain is the most common symptom for which patients seek medical help, and can be classified as either acute or chronic. Acute pain is precipitated by immediate tissue injury (e.g., a burn or a cut), and is usually self-limited. This form of pain is a natural defense mechanism in response to immediate tissue injury, preventing further use of the injured body part, and withdrawal from the painful stimulus. It is amenable to traditional pain therapeutics, including non-steroidal anti-inflammatory drugs (NSAIDs) and opioids. In contrast, chronic pain is present for an extended period, e.g., for 3 or more months, persisting after an injury has resolved, and can lead to significant changes in a patient's life (e.g., functional ability and quality of life) (Foley, Pain, In: Cecil Textbook of Medicine, pp. 100-107, Bennett and Plum eds., 20th ed., 1996).
[0003] Chronic debilitating pain represents a significant medical dilemma. Pain can be classified as either “nociceptive” or “neuropathic”. “Nociceptive pain” results from activation of pain sensitive nerve fibers, either somatic or visceral. Nociceptive pain is generally a response to direct tissue damage. The term “neuropathic pain” refers to pain that is due to injury or disease of the central or peripheral nervous system. In contrast to the immediate pain caused by tissue injury, neuropathic pain can develop days or months after a traumatic injury. Furthermore, while pain caused by tissue injury is usually limited in duration to the period of tissue repair, neuropathic pain frequently is long lasting or chronic. Moreover, neuropathic pain can occur spontaneously or as a result of stimulation that normally is not painful. Neuropathic pain is common in the following conditions: postherpetic neuralgia, trigeminal neuralgia, AIDS-related neuropathy, causalgia, diabetic neuropathy, chronic low back pain, back and neck pain with neuropathic involvement, phantom limb pain, atypical facial pain and cancer neuropathy (Berger et al., 2004, J. Pain 5:143-149).
[0004] Unfortunately, neuropathic pain is often resistant to available drug therapies; a hallmark of neuropathic pain is its intractability. Typical non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin, indomethecin, and ibuprofen do not relieve neuropathic pain. The neuropathic pain observed in animal models predictive of human clinical outcome does not respond to NSAIDs. Treatments for neuropathic pain include opioids, anti-epileptics, NMDA antagonists, topical Lidocaine, topical Capsaicin and tricyclic anti-depressants. Current therapies have limited efficacy and may have serious side effects such as abuse potential, cognitive changes, sedation, and nausea. Many patients suffering from neuropathic pain have limited tolerance of such side effects. Accordingly, there is a need for additional neuropathic pain therapies.
PPAR Gamma Signaling Pathway and Modulators Thereof
[0005] The peroxisome proliferator-activated receptors (PPARs: α β/δ and γ) are a subfamily of ligand-inducible nuclear hormone transcription factors with roles in a range of physiological processes and disease states. PPARγ is widely expressed, particularly in tissues important for insulin action such as adipose tissue, skeletal muscle and liver. In the treatment of diabetes, activation of PPARγ improves glycemic control by improving insulin sensitivity, via activation of genes involved in the control of glucose production, transport and utilization.
[0006] PPARα is localized in tissues of the heart, liver and muscle, where it plays an important role in lipid metabolism by controlling genes relating to cellular free fatty acid metabolism and cholesterol trafficking PPARα activation decreases serum triglycerides (TGs) and increases levels of serum high-density lipoprotein (HDL)-cholesterol. Hypertriglyceridemia and low serum HDL-cholesterol are characteristic of both diabetic dyslipidemia and insulin resistance syndrome.
[0007] PPARγ has been identified as a potential target for neuropathic pain therapeutics, but the mechanism of neuropathic pain treatment through modulation of PPARγ has not been elucidated and is not understood. The Inventor's previously published PCT Patent Application WO 2008/063842 teaches PPARγ agonists as therapeutic agents for treating neuropathic pain. Other publications suggest antagonism of PPARγ for neuropathic pain therapy. In Published PCT Patent Application WO2006085686 , Remedy for Neurogenic Pain , Tanabe & Tsutomu, Tokyo Medical & Dental University state: “ . . . it is intended to provide a remedy for neurogenic pain which contains, as the active ingredient, a PPARgamma antagonist (such as 2-chloro-5-nitro-N-phenylbenzamide) . . . a medicinal composition for treating neurogenic pain which contains, as the active ingredient, a PPAR antagonist . . . ” Tanabe and Tsutomu demonstrate that GW9662, a PPARγ antagonist demonstrates activity in a neurogenic pain model. Accordingly it is not clear whether agonism or antagonism of PPARγ results in therapeutic effects on neuropathic pain.
[0008] Even among the PPARγ agonists specifically taught by Published PCT Patent Application WO 2008/063842 (Tesaglitazar, Muraglitazar, Peliglitazar, Farglitazar, Reglitazar, Naveglitazar, Oxeglitazar, Edaglitazone, Imiglitazar and Sipoglitazar), further animal model testing has revealed a diversity of results. For instance, neither of Muraglitazar or Tesaglitazar showed any statistically significant difference from a vehicle control in the Bennett neuropathic pain animal model described below. See FIG. 1 for results. Therefore, it is not predictable whether any particular agonist or antagonist will or will not therapeutically reduce neuropathic pain.
[0009] Published PCT Applications WO 97/24334 and WO 00/29383 to Noritsugu Yamasaki et al., and related U.S. Pat. Nos. 6,166,219, 6,352,985, 6,703,410 and EP Patent 0882718 B1 teach benzimidazole derivatives having hypoglycemic or PPARγ agonist activity. Each of these patents and patent applications is incorporated herein by reference. Yamasaki et al. teach PPARγ agonist benzimidazole derivatives of Formula I:
[0000]
wherein
R 1 represents a hydrogen atom, an arylsulfonyl group, or a lower alkyl group; said lower alkyl group may be substituted by an aryl group or an aryl group substituted by one or two substituents selected from a halogen atom, a haloaryl group, a lower alkyl group, a halo-lower alkyl group, a lower alkoxy group, a nitro group, an amino group, a cyano group, an aryl group, an aryl-lower alkyloxy group, an arylsulfonyl-lower alkyl group, an aryl-lower alkyl group, a haloaryl-lower alkyloxy group, an arylsulfonylamino group, an arylcarbonylamino group, an arylcarbonyl group, an arylalkenyl group, a cyanoaryl group, and a heterocyclic group, or by a heterocyclic group;
R 2 represents a hydrogen atom, a lower cycloalkyl group, a hydroxyl group, a hydroxy-lower alkyl group, a lower alkoxy group, a mercapto group, a lower alkylthio group, an amino group, a lower alkylamino group, a carboxyl group, an aryl group, or a lower alkyl group; said lower alkyl group may be substituted by a halogen atom, a lower alkoxy group, a cyano group, a halocarbonyl group, an aryl group, or a heterocyclic group;
R 25 represents an alkyl group having up to 8 carbon atoms, a lower cycloalkyl group, a halo-lower alkyl group, a tri-lower alkylsilyl-lower alkyl group, a lower alkoxy-lower alkyl group, a lower alkylthio-lower alkyl group, an aryl group, a heterocyclic group, an aryl-lower alkyl group, or a hydroxy-lower alkyl group; said aryl group may be substituted by a halogen atom, a lower alkyl group, a halo-lower alkyl group, a lower alkoxy group, or a nitro group;
R 26 represents a hydrogen atom or a lower alkyl group; provided that, when R 25 and R 26 are both lower alkyl groups, they may be bonded together to form a ring;
Y represents a carbonyl group or a lower alkylene group;
A represents a single bond, or a lower alkylene or alkenylene group;
R 4 ′ represents a hydrocarbon group or a halogenated hydrocarbon group; and
n means an integer from 0 to 3;
wherein
the arylsulfonyl group is selected from a benzenesulfonyl group, a toluenesulfonyl group, and a naphthalenesulfonyl group;
the term “lower” indicates that the group has from 1 to 6 carbon atoms, unless otherwise specifically indicated;
the aryl group is selected from a phenyl group and a naphthyl group, which may optionally be substituted by one or more substituents selected from a halogen atom, a lower alkyl group, a cyano group, a nitro group and a trifluoromethyl group;
the halo-lower alkyl group is a linear or branched alkyl group having up to 8 carbon atoms, which is substituted with one or more halogen atoms;
the heterocyclic group is selected from a pyridyl group, a quinolyl group, an isoquiriolyl group, a thiazolyl group, a thiadiazolyl group, a benzofuranyl group, a dibenzofuranyl group, a thianaphthalenyl group, a 1H-1,2,3-triazolyl group, a 1,2,4-triazolyl group, a tetrazolyl group, a furyl group, a thienyl group, a pyrrolyl group, an imidazolyl group, a pyrimidinyl group, an indolyl group, a benzimidazolyl group, which groups may optionally be substituted by one or more substituents of halogen atoms and lower alkyl groups; and
the lower cycloalkyl group is a cycloalkyl group having from 3 to 7 carbon atoms
or a pharmaceutically acceptable salt thereof.
[0027] Yamasaki et al. further teach PPARγ agonist benzimidazole derivatives of Formula II:
[0000]
wherein:
R 27 represents a hydrogen atom, a lower alkyl group, an arylsulfonyl group or an aryl-lower alkyl group; wherein the aromatic ring moiety in said aryl-lower alkyl group may be substituted by one or two substituents selected from a halogen atom, a lower alkyl group, a halo-lower alkyl group, a cyanoaryl group, an amino group, a lower alkoxy group, a nitro group, a cyano group, an aryl group, a haloaryl group, an arylsulfonyl-lower alkyl group, an arylsulfonylamino group, an aryl-lower alkyloxy group, an aryl-lower alkyl group, a heterocyclic group, an arylcarbonyl group, an arylcarbonylamino group, and an aryl-lower alkyloxy group substituted by one or two halogen atoms;
R 28 represents a hydrogen atom, a lower alkyl group, a halo-lower alkyl group, a lower alkoxy-lower alkyl group, a lower cycloalkyl group, an aryl group, an aryl-lower alkyl group, a lower alkylamino group, a lower alkoxy group, a lower alkylthio group, a hydroxyl group, a mercapto group, an amino group, or a carboxyl group;
R 25 represents an alkyl group having up to 8 carbon atoms, a halo-lower alkyl group, a tri-lower alkylsilyl-lower alkyl group, a lower alkoxy-lower alkyl group, a lower alkylthio-lower alkyl group, an aryl group, a heterocyclic group, an aryl-lower alkyl group, or a hydroxy-lower alkyl group; said aryl group may be substituted by a halogen atom, a lower alkyl group, a halo-lower alkyl group, a lower alkoxy group, or a nitro group;
R 26 represents a hydrogen atom or a lower alkyl group; provided that, when R 25 and R 26 are both lower alkyl groups, they may be bonded together to form a ring;
Y represents a carbonyl group or a lower alkylene group;
A represents a single bond, or a lower alkylene or alkenylene group; and
R 29 represents a hydrogen atom or a lower alkyl group
or a pharmaceutically acceptable salt thereof.
[0037] Yamasaki et al. further teach PPARγ agonist benzimidazole derivatives of Formula II, wherein all groups are as given above, except:
R 27 represents an aryl lower alkyl group whose aryl moiety may be substituted by one or two substituents selected from the group consisting of a halogen atom, a lower alkyl group, a halo-lower alkyl group, a cyanoaryl group, an amino group, a lower alkoxy group, a nitro group, a cyano group, an aryl group, a haloaryl group, an arylsulfonyl-lower alkyl group, an arylsulfonylamino group, an aryl-lower alkyloxy group, an aryl-lower alkyl group, a heterocyclic group, an arylcarbonyl group, an arylcarbonylamino group, and an aryl-lower alkyloxy group substituted by one or two halogen atoms; Y represents a carbonyl group; and A represents a single bond.
[0041] Yamasaki et al. further teach PPARγ agonist benzimidazole derivatives of Formula II, wherein all groups are as given above, except:
R 27 represents an aryl lower alkyl group whose aryl moiety may be substituted by one or two substituents selected from a halogen atom or an aryl group; R 28 represents a lower alkyl group or a lower cycloalkyl group; R 25 represents an alkyl group having up to 8 carbon atoms or an aryl group; Y represents a carbonyl group; and A represents a single bond.
[0047] All chemical groups recited herein are defined according to the disclosure of Yamasaki et al. in EP 0882718 B1.
[0048] Particular PPARγ agonist benzimidazole derivatives taught by Yamasaki et al. include 3-(2,4-dichlorobenzyl)-2-methyl-N-(pentylsulfonyl)-3H-benzimidazole-5-carboxamide, 6-benzenesulfonylcarbamoyl-1-(2-chlorobenzyl)-2-methylbenzimidazole, 1-(biphenyl-4-ylmethyl)-6-(1-butanesulfonylcarbamoyl)-2-methylbenzimidazole, 1-(biphenyl-4-ylmethyl)-6-(1-butanesulfonylcarbamoyl)-2-ethylbenzimidazole, 6-benzenesulfonylcarbamoyl-2-cyclopropyl-1-(2-fluorobenzyl)-benzimidazole, 6-benzenesulfonylcarbamoyl-1-(2,4-dichlorobenzyl)-2-methylbenzimidazole, 6-benzenesulfonylcarbamoyl-1-(2,4-difluorobenzyl)-2-methylbenzimidazole, 6-(1-butanesulfonylcarbamoyl)-1-[(3-fluorobiphenyl-4-yl)methyl]-2-methylbenzimidazole, 1-(2,4-dichlorobenzyl)-2-methyl-6-(1-pentanesulfonylcarbamoyl)benzimidazole, 1-(4-biphenylmethyl)-2-ethyl-6-(1-pentanesulfonylcarbamoyl)benzimidazole, and pharmaceutically acceptable salts thereof.
[0049] Yamasaki et al. also teach methods of making the above PPARγ agonist benzimidazole derivatives, formulating them into pharmaceutical compositions and administering them in doses from 0.1 to 100 mg/kg, one to four times a day.
[0050] The benzimidazole derivative 3-(2,4-dichlorobenzyl)-2-methyl-N-(pentylsulfonyl)-3H-benzimidazole-5-carboxamide completed a Phase I clinical trial for Astellas Pharma Inc., and was entered into a Phase II clinical trial for type 2 diabeties (see clinicaltrials.gov, trial identifier NCT00036192). “While [3-(2,4-dichlorobenzyl)-2-methyl-N-(pentylsulfonyl)-3H-benzimidazole-5-carboxamide] advanced to Phase II clinical trials, its development was recently discontinued when no advantage [for type 2 diabetes] was demonstrated in clinical trials,” Meinke, Peter T., et al., “Nuclear Hormone Receptor Modulators for the Treatment of Diabetes and Dyslipidemia”, Annual Reports in Medicinal Chemistry (2006) 141:99-126, p. 109.
SUMMARY
[0051] Neuropathic pain in mammals is treated by the administration of a therapeutically effective amount of an agonist of Peroxisome Proliferator-Activated Receptor gamma (PPARγ), wherein the agonist is a compound of Formula I or Formula II.
[0052] An embodiment of the invention is a composition for the treatment of neuropathic pain comprising at least one agonist of the PPARγ or a salt, ester, hydrate, solvate, prodrug or polymorph thereof, incorporated in a pharmaceutically acceptable adjuvant, excipient, diluent or carrier composition, wherein the agonist is a compound of Formula I or Formula II.
[0053] An embodiment of the invention is a method of treating neuropathic pain in a mammal in need of such treatment, comprising administering a therapeutically effective amount of an agonist of PPARγ or a salt, ester, hydrate, solvate, prodrug or polymorph thereof, wherein the agonist is a compound of Formula I or Formula II.
[0054] An embodiment of the invention is a method of treating neuropathic pain in a mammal in need of such treatment comprising administering a therapeutically effective amount of a compound selected from the group consisting of 3-(2,4-dichlorobenzyl)-2-methyl-N-(pentylsulfonyl)-3H-benzimidazole-5-carboxamide, 6-benzenesulfonylcarbamoyl-1-(2-chlorobenzyl)-2-methylbenzimidazole, 1-(biphenyl-4-ylmethyl)-6-(1-butanesulfonylcarbamoyl)-2-methylbenzimidazole, 1-(biphenyl-4-ylmethyl)-6-(1-butanesulfonylcarbamoyl)-2-ethylbenzimidazole, 6-benzenesulfonylcarbamoyl-2-cyclopropyl-1-(2-fluorobenzyl)-benzimidazole, 6-benzenesulfonylcarbamoyl-1-(2,4-dichlorobenzyl)-2-methylbenzimidazole, 6-benzenesulfonylcarbamoyl-1-(2,4-difluorobenzyl)-2-methylbenzimidazole, 6-(1-butanesulfonylcarbamoyl)-1-[(3-fluorobiphenyl-4-yl)methyl]-2-methylbenzimidazole, 1-(2,4-dichlorobenzyl)-2-methyl-6-(1-pentanesulfonylcarbamoyl)benzimidazole, 1-(4-biphenylmethyl)-2-ethyl-6-(1-pentanesulfonylcarbamoyl)benzimidazole and salts, hydrates, solvates, esters, prodrugs, and polymorphs thereof.
[0055] Another embodiment of the invention comprises compositions used for treating neuropathic pain comprising at least one compound selected from the group consisting of 3-(2,4-dichlorobenzyl)-2-methyl-N-(pentylsulfonyl)-3H-benzimidazole-5-carboxamide, 6-benzenesulfonylcarbamoyl-1-(2-chlorobenzyl)-2-methylbenzimidazole, 1-(biphenyl-4-ylmethyl)-6-(1-butanesulfonylcarbamoyl)-2-methylbenzimidazole, 1-(biphenyl-4-ylmethyl)-6-(1-butanesulfonylcarbamoyl)-2-ethylbenzimidazole, 6-benzenesulfonylcarbamoyl-2-cyclopropyl-1-(2-fluorobenzyl)-benzimidazole, 6-benzenesulfonylcarbamoyl-1-(2,4-dichlorobenzyl)-2-methylbenzimidazole, 6-benzenesulfonylcarbamoyl-1-(2,4-difluorobenzyl)-2-methylbenzimidazole, 6-(1-butanesulfonylcarbamoyl)-1-[(3-fluorobiphenyl-4-yl)methyl]-2-methylbenzimidazole, 1-(2,4-dichlorobenzyl)-2-methyl-6-(1-pentanesulfonylcarbamoyl)benzimidazole, 1-(4-biphenylmethyl)-2-ethyl-6-(1-pentanesulfonylcarbamoyl)benzimidazole and salts, hydrates, solvates, esters, prodrugs, and polymorphs thereof, incorporated in a pharmaceutically acceptable adjuvant, excipient, diluent, or carrier composition.
[0056] To apply the benzimidazole derivatives according to the present invention, they may be formulated into pharmaceutical compositions of ordinary forms, which comprise, as an active ingredient, any of the derivatives along with pharmaceutically acceptable carriers, such as organic or inorganic solid or liquid vehicles, and which are suitable for per oral administration, parenteral administration or external application. The pharmaceutical compositions may be of any solid form of tablets, granules, powders, capsules, etc., or may be of any liquid form of solutions, suspensions, syrups, emulsions, lemonades, etc.
[0057] If desired, the pharmaceutical compositions may further contain a pharmaceutical aid, a stabilizer, a wetting agent, and also any ordinary additive of, for example, lactose, citric acid, tartaric acid, stearic acid, magnesium stearate, terra alba, sucrose, corn starch, talc, gelatin, agar, pectin, peanut oil, olive oil, cacao butter, ethylene glycol, etc.
[0058] The amount of the above-mentioned derivative of the present invention to be used shall vary, depending on the age and the condition of patients, the type and the condition of diseases or disorders, and the type of the derivative to be used. In general, for peroral administration, the dose of the derivative may be from 0.01 to 1 mg/kg; and for intramuscular injection or intravenous injection, it may be from 1 to 100 μg/kg. Such a unit dose may be applied to a patient once to four times a day.
DESCRIPTION OF THE FIGURES
[0059] FIG. 1 —Efficacy of PPARγ agonists Muraglitizar and Tesaglitizar in Bennett animal model for neuropathic pain. PPAR agonist compounds and positive control carbamazepine were dosed orally at 100 mg/kg, and pain behavior was measured one hour later with the cold allodynia test, as the latency time to removal of the affected paw from a cold plate. Statistical analysis of raw data was performed by analysis of variance (ANOVA), with significance threshold set at p<0.05. Analgesic activity was determined as a statistically significant increase in latency time to paw withdrawal in treated animals as compared to vehicle-treated animals. Comparisons for statistically significant differences in latency times were made between PPAR agonist compound-treated animals and vehicle controls, between carbamazepine-treated animals and vehicle controls, and between PPAR agonist compound-treated animals and carbamazepine-treated animals from the same experiment. All statistically significant differences between compared groups are indicated by the brackets, with *=p<0.05, and **=p<0.001.
[0060] FIG. 2 —Effect of carbamazepine (+control) and 3-(2,4-dichlorobenzyl)-2-methyl-N-(pentylsulfonyl)-3H-benzimidazole-5-carboxamide (“Atx” in Figure) on the latency to lift paw from the cold plate at different time points following administration of 100 mg/kg PO in the Bennett model. Statistical analysis of data as for FIG. 1 ; *=p, 0.05 and ˜=p<0.1 compared to vehicle control.
[0061] FIG. 3 —Effect of carbamazepine (+control) and 3-(2,4-dichlorobenzyl)-2-methyl-N-(pentylsulfonyl)-3H-benzimidazole-5-carboxamide (“Atx” in Figure) on the latency to lift paw from the cold plate 60 min following compound injection, in rats with the Bennett model of neuropathic pain. Data represent mean±SEM. Statistical analysis of data as for FIG. 1 ; *=p<0.05. Note that ATx-treated animals show analgesic activity which is significantly greater than vehicle alone, and not significantly different from carbamazepine.
[0062] FIG. 4 —Dose response of 3-(2,4-dichlorobenzyl)-2-methyl-N-(pentylsulfonyl)-3H-benzimidazole-5-carboxamide (“Atx” in Figure) and carbamazepine (+control) on the latency to lift paw from the cold plate in rats with the Bennett neuropathic pain model. Paw latency times were measured at 1 hour following administration of compounds at different doses PO. Statistical analysis of data as for FIG. 1 ; *=p<0.05.
DETAILED DESCRIPTION
[0063] Embodiments of the invention provide methods for treating neuropathic pain by the administration of a therapeutically effective amount of an agonist of PPARγ of Formula I or Formula II.
[0064] According to embodiments of the invention, a therapeutically effective amount of a compound of Formula I or Formula II that agonizes PPARγ is administered to a subject to treat neuropathic pain. In one embodiment of the invention, the therapeutically effective amount of a compound of Formula I or Formula II that agonizes PPARγ is administered to a subject to treat pain in a subject with postherpetic neuralgia, trigeminal neuralgia, AIDS-related neuropathy, diabetic neuropathy, chronic low back pain, or cancer neuropathy. In another embodiment of the invention, the therapeutically effective amount of a compound of Formula I or Formula II that agonizes PPARγ is administered to a subject to treat pain in a subject with postherpetic neuralgia, trigeminal neuralgia, AIDS-related neuropathy, chronic low back pain, or cancer neuropathy. In another embodiment of the invention, the therapeutically effective amount of a compound of Formula I or Formula II that agonizes PPARγ is administered to a subject to treat neuropathic pain, wherein the subject does not have diabetic neuropathy. A compound useful in carrying out a therapeutic method embodiment of the invention is advantageously formulated in a pharmaceutical composition in combination with a pharmaceutically acceptable carrier. The amount of compound in the pharmaceutical composition depends on the desired dosage and route of administration. In one embodiment, suitable dose ranges of the active ingredient are from about 1 μg/kg to about 100 mg/kg of body weight taken at necessary intervals (e.g., daily, every 12 hours, etc.). In another embodiment, a suitable dosage range of the active ingredient is from about 2 μg/kg to about 200 μg/kg of body weight taken at necessary intervals. In another embodiment, a suitable dosage range of the active ingredient is from about 20 μg/kg to about 125 μg/kg of body weight taken at necessary intervals.
[0065] In one embodiment of the method of treating neuropathic pain, the dosage and administration are such that PPARγ is only partially inhibited so as to avoid any unacceptably deleterious effects.
[0066] A therapeutically effective compound can be provided to the subject in a standard formulation that includes one or more pharmaceutically acceptable additives, such as excipients, lubricants, diluents, flavorants, colorants, buffers, and disintegrants. The formulation may be produced in unit dosage from for administration by oral, parenteral, transmucosal, intranasal, rectal, vaginal, or transdermal routes. Parenteral routes include intravenous, intra-arterial, intramuscular, intradermal subcutaneous, intraperitoneal, intraventricular, intrathecal, and intracranial administration.
[0067] The pharmaceutical composition can be added to a retained physiological fluid such as blood or synovial fluid. In one embodiment, for example, to target the peripheral nervous system (PNS), the pharmaceutical composition has a restricted ability to cross the blood brain barrier and can be administered using techniques known in the art.
[0068] In another embodiment of the method of treating neuropathic pain, the agonist of PPARγ is delivered in a vesicle, particularly a liposome. In one embodiment, the agonist of PPARγ is delivered topically (e.g., in a cream) to the site of pain (or related disorder) to avoid the systemic effects of agonizing PPARγ in non-target cells or tissues.
[0069] In another embodiment of the method of treating neuropathic pain, the therapeutic agent is delivered in a controlled release manner. For example, a therapeutic agent can be administered using intravenous infusion with a continuous pump, or in a polymer matrix such as poly-lactic/glutamic acid (PLGA), or in a pellet containing a mixture of cholesterol and the active ingredient, or by subcutaneous implantation, or by transdermal patch.
[0070] Specific examples of methods of treating neuropathic pain according to the invention include administration of therapeutically effective amounts of a PPARγ agonist of Formula II selected from the group consisting of: 6-benzenesulfonylcarbamoyl-1-(2-chlorobenzyl)-2-methylbenzimidazole, 6-benzenesulfonylcarbamoyl-1-(biphenyl-4-ylmethyl)-2-ethylbenzimidazole, 5-benzenesulfonylcarbamoyl-1-(2-chlorobenzyl)-2-methylbenzimidazole, 5-(4-chlorobenzenesulfonylcarbamoyl)-1-(2-chlorobenzyl)-2-methylbenzimidazole, 1-(2-chlorobenzyl)-2-methyl-5-(2-naphthalenesulfonylcarbamoyl)-benzimidazole, 1-(2-chlorobenzyl)-6-methanesulfonylcarbamoyl-2-methylbenzimidazole, 6-(1-butanesulfonylcarbamoyl)-1-(2-chlorobenzyl)-2-methylbenzimidazole, 1-(2-chlorobenzyl)-2-methyl-6-(1-octanesulfonylcarbamoyl)benzimidazole, 1-(2-chlorobenzyl)-2-methyl-6-(2-propanesulfonylcarbamoyl)benzimidazole, 1-(biphenyl-4-ylmethyl)-6-(1-butanesulfonylcarbamoyl)-2-methylbenzimidazole, 6-(1-butanesulfonylcarbamoyl)-1-(2,4-dichlorobenzyl)-2-methylbenzimidazole, 1-(biphenyl-4-ylmethyl)-6-(1-butanesulfonylcarbamoyl)-2-ethylbenzimidazole, 6-benzenesulfonylcarbamoyl-1-(biphenyl-4-ylmethyl)-2-trifluoromethylbenzimidazole, 5-benzenesulfonylcarbamoyl-1-(biphenyl-4-ylmethyl)-2-trifluoromethylbenzimidazole, 6-benzenesulfonylcarbamoyl-2-cyclopropyl-1-(2-fluorobenzyl)benzimidazole, Nbenzenesulfonyl-3-[1-(2-chlorobenzyl)-2-methylbenzimidazol-6-yl]acrylamide, N-benzenesulfonyl-2-[1-(2-chlorobenzyl)-2-methylbenzimidazol-6-yl]acetamide, 1-(2-chlorobenzyl)-2-methyl-6-(2-naphthalenesulfonylcarbamoyl)benzimidazole, 1-(2-chlorobenzyl)-2-methyl-6-(1-naphthalenesulfonylcarbamoyl)benzimidazole, 6-(4-chlorobenzenesulfonylcarbamoyl)-1-(2-chlorobenzyl)-2-methylbenzimidazole, 6-(3-chlorobenzenesulfonylcarbamoyl)-1-(2-chlorobenzyl)-2-methylbenzimidazole, 5-benzenesulfonylcarbamoyl-2-benzyl-1-(2-chlorobenzyl)benzimidazole, 6-benzenesulfonylcarbamoyl-2-benzyl-1-(2-chlorobenzyl)benzimidazole, 6-benzenesulfonylcarbamoyl-1-(biphenyl-4-ylmethyl)-2-methylbenzimidazole, 1-(2-chlorobenzyl)-2-methyl-6-trifluoromethanesulfonylcarbamoylbenzimidazole, 6-benzenesulfonylcarbamoyl-1-(2,4-dichlorobenzyl)-2-methylbenzimidazole, 1-(2-chlorobenzyl)-6-(4-methoxybenzenesulfonylcarbamoyl)-2-methylbenzimidazole, 1-(2-chlorobenzyl)-2-methyl-6-(a-toluenesulfonylcarbamoyl)benzimidazole, 1-(2-chlorobenzyl)-6-(2,5-dimethylbenzenesulfonylcarbamoyl)-2-methylbenzimidazole, 1-(2-chlorobenzyl)-2-methyl-6-(4-nitrobenzenesulfonylcarbamoyl)-benzimidazole, 1-(2-chlorobenzyl)-2-methyl-6-[4-(trifluoromethyl)benzenesulfonylcarbamoyl]benzimidazole, 6-(2-chlorobenzenesulfonylcarbamoyl)-1-(2-chlorobenzyl)-2-methylbenzimidazole, 6-benzenesulfonylcarbamoyl-2-benzyl-1-(2,4-dichlorobenzyl)benzimidazole, 5-benzenesulfonylcarbamoyl-2-benzyl-1-(2,4-dichlorobenzyl)benzimidazole, 6-benzenesulfonylcarbamoyl-1-(biphenyl-4-ylmethyl)-2-hydroxybenzimidazole, 6-benzenesulfonylcarbamoyl-1-(biphenyl-4-ylmethyl)-2-mercaptobenzimidazole, 6-benzenesulfonylcarbamoyl-1-(biphenyl-4-ylmethyl)-2-methoxybenzimidazole, 6-benzenesulfonylcarbamoyl-1-(biphenyl-4-ylmethyl)-2-carboxybenzimidazole, 6-benzenesulfonylcarbamoyl-1-(biphenyl-4-ylmethyl)-2-methylaminobenzimidazole, 2-amino-6-benzenesulfonylcarbamoyl-1-(biphenyl-4-ylmethyl)-benzimidazole, 6-benzenesulfonylcarbamoyl-1-(biphenyl-4-ylmethyl)-2-n-propylbenzimidazole, 6-benzenesulfonylcarbamoyl-1-(biphenyl-4-ylmethyl)-2-n-heptylbenzimidazole, 6-benzenesulfonylcarbamoyl-1-(biphenyl-4-ylmethyl)-2-chloromethylbenzimidazole, 6-benzenesulfonylcarbamoyl-1-(biphenyl-4-ylmethyl)-2-methoxymethylbenzimidazole, 6-benzenesulfonylcarbamoyl-1-(biphenyl-4-ylmethyl)-2-i-propylbenzimidazole, 6-benzenesulfonylcarbamoyl-1-(biphenyl-4-ylmethyl)-2-methylthiobenzimidazole, 6-benzenesulfonylcarbamoyl-1-(biphenyl-4-ylmethyl)-2-ethylthiobenzimidazole, 6-benzenesulfonylcarbamoyl-1-(biphenyl-4-ylmethyl)-2-npropylthiobenzimidazole, 6-benzenesulfonylcarbamoyl-1-(biphenyl-4-ylmethyl)-2-n-hexylthiobenzimidazole, 6-benzenesulfonylcarbamoyl-1-(biphenyl-4-ylmethyl)benzimidazole, 6-benzenesulfonylcarbamoyl-1-(2,4-difluorobenzyl)-2-methylbenzimidazole, 6-benzenesulfonylcarbamoyl-1-(biphenyl-4-ylmethyl)-2-phenylbenzimidazole, 6-benzenesulfonylcarbamoyl-2-methyl-1-(2-nitrobenzyl)-benzimidazole, 6-benzenesulfonylcarbamoyl-2-methyl-1-benzylbenzimidazole, 6-benzenesulfonylcarbamoyl-2-methyl-1-(4-nitrobenzyl)benzimidazole, 6-benzenesulfonylcarbamoyl-1-(4-benzyloxybenzyl)-2-methylbenzimidazole, 6-benzenesulfonylamino-methyl-1-(2-chlorobenzyl)-2-methylbenzimidazole, N-benzenesulfonyl-3-[1-(2-chlorobenzyl)-2-methylbenzimidazol-6-yl]propionamide, 6-benzenesulfonylcarbamoyl-2-methyl-1-[4-(1,2,3-thiadiazol-4-yl)benzyl]benzimidazole, 1-(2-chlorobenzyl)-2-methyl-6-(8-quinolinesulfonylcarbamoyl)benzimidazole, 6-(4-t-butylbenzenesulfonylcarbamoyl)-1-(2-chlorobenzyl)-2-methylbenzimidazole, 6-benzenesulfonylcarbamoyl-2-methyl-1-[4-(trifluoromethyl)benzyl]benzimidazole, 5-benzenesulfonylcarbamoyl-2-methylbenzimidazole, 1-(biphenyl-4-ylmethyl)-6-(1-butanesulfonylcarbamoyl)-2-methoxymethylbenzimidazole, 1-(4-benzyloxybenzyl)-6-(1-butanesulfonylcarbamoyl)-2-methoxymethylbenzimidazole, 6-(1-butanesulfonylcarbamoyl)-1-(2,4-dichlorobenzyl)-2-methoxymethylbenzimidazole, 1-(2-chlorobenzyl)-2-methyl-6-(1-propanesulfonylcarbamoyl)benzimidazole, 6-ethanesulfonylcarbamoyl-1-(2-chlorobenzyl)-2-methylbenzimidazole, 6-(propanesultam-1-ylcarbonyl)-1-(2-chlorobenzyl)-2-methylbenzimidazole, 6-benzenesulfonylcarbamoyl-1-(biphenyl-4-ylmethyl)-2-cyclopropylbenzimidazole, 1-(2-chlorobenzyl)-2-methyl-6-(1-pentanesulfonylcarbamoyl)benzimidazole, 1-(2-chlorobenzyl)-2-methyl-6-[(3-methylbutane)sulfonylcarbamoyl]-benzimidazole, 1-(2-chlorobenzyl)-6-(1-hexanesulfonylcarbamoyl)-2-methylbenzimidazole, 7-(1-butanesulfonylcarbamoyl)-1-(2,4-dichlorobenzyl)-2-methylbenzimidazole, 1-(2-chlorobenzyl)-2-methyl-6-[1-[3-(trimethylsilyl)propane]sulfonylcarbamoyl]-benzimidazole, 4-(1-butanesulfonylcarbamoyl)-1-(2,4-dichlorobenzyl)-2-methylbenzimidazole, 1-(4-benzyloxybenzyl)-6-(1-butanesulfonylcarbamoyl)-2-methylbenzimidazole, 6-(1-butanesulfonylcarbamoyl)-1-[(2′-cyanobiphenyl-4-yl)methyl]-2-methylbenzimidazole, 6-(1-ethanesulfonylcarbamoyl)-1-[(2′-fluorobiphenyl-4-yl)methyl]-2-methylbenzimidazole, 6-(1-butanesulfonylcarbamoyl)-1-[(3-fluorobiphenyl-4-yl)methyl]-2-methylbenzimidazole, 1-(2-chlorobenzyl)-6-[(2-methoxyethane)-sulfonylcarbamoyl]-2-methylbenzimidazole, 1-(2-chlorobenzyl)-6-(1-hexanesulfonylcarbamoyl)-2-methylbenzimidazole, 1-(2,4-dichlorobenzyl)-2-methyl(1-pentanesulfonylcarbamoyl)-benzimidazole, 1-(biphenyl-4-ylmethyl)-2-ethyl-6-[1-[3-(methylthio)propane]sulfonylcarbamoyl]benzimidazole, 1-(4-biphenylmethyl)-2-ethyl-6-(1-pentanesulfonylcarbamoyl)benzimidazole, 6-(1-butanesulfonylcarbamoyl)-1-(2,4-dichlorobenzyl)-2-ethylbenzimidazole, 1-(4-biphenylmethyl)-2-ethyl-6-[1-(3-methyl)-butanesulfonylcarbamoyl]benzimidazole, 5-(1-butanesulfonylcarbamoyl)-1-(2,4-dichlorobenzyl)-2-methylbenzimidazole, 1-(4-biphenylmethyl)-5-(1-butanesulfonylcarbamoyl)-2-ethylbenzimidazole, 1-(4-biphenylmethyl)-2-ethyl-6-(2-methoxy-ethanesulfonylcarbamoyl)benzimidazole, 6-(1-butanesulfonylcarbamoyl)-2-ethyl-1-[4-(4-fluorobenzyloxy)benzyl]benzimidazole, 6-(1-butanesulfonylcarbamoyl)-1-[4-(3,4-dichlorobenzyloxy)-benzyl]-2-ethylbenzimidazole, 6-(1-butanesulfonylcarbamoyl)-1-[sec-(2,4-dichlorophenethyl)]-2-methylbenzimidazole, 6-(1-butanesulfonylcarbamoyl)-1-[4-(2-pyridyl)benzyl]-2-methylbenzimidazole, 6-(1-butanesulfonylcarbamoyl)-1-(2,4-dichlorobenzyl)-2,4-dimethylbenzimidazole, 6-(1-butanesulfonylcarbamoyl)-2-methyl-1-(4-phenoxybenzyl)benzimidazole, 6-(butanesulfonylcarbamoyl)-2-methyl-1-(2-pyridylmethyl)benzimidazole, 1-[(4-benzoylamino)benzyl]-6-(1-butanesulfonylcarbamoyl)-2-methylbenzimidazole, 6-(1-butanesulfonylcarbamoyl)-2-methyl-[4-(2-phenylethyl)benzyl]benzimidazole, 1-[(4-benzoyl)benzyl]-6-(1-butanesulfonylcarbamoyl)-2-methylbenzimidazole, 6-(1-butanesulfonylcarbamoyl)-2-methyl-[4-(2-phenylethenyl)benzyl]-benzimidazole, 1-(dibenzofuran-2-ylmethyl)-6-(1-butanesulfonylcarbamoyl)-2-methylbenzimidazole, 6-(1-butanesulfonylcarbamoyl)-1-(2,4-dichlorobenzyl)-2-hydroxybenzimidazole, 6-(1-butanesulfonylcarbamoyl)-2-methyl-1-(2-quinolylmethyl)benzimidazole, and 6-(1-butanesulfonylcarbamoyl)-2-methyl-1-[3-(4-bromoisoquinolyl)methyl]benzimidazole.
[0071] Experimental Protocol
[0072] Three neuropathic pain models in rats have been shown to correlate well to clinical outcome both with respect to the rank order of active (Gabapentin, Pregabalin, Amitriptyline, Carbamazepine and N-type Ca++ blockers) and inactive (SSRI and NSAIDs) substances, and also between experimental and effective therapeutic doses. These models are based on three surgical procedures: (i) the spinal nerve ligation (SNL) [Kim, S, and J. Chung, An experimental model for peripheral neuropathy produced by segmental spinal nerve ligation in the rat. Pain, 1992. 50: p. 355-363]; (ii) the partial sciatic nerve lesion (Seltzer) [Seltzer, Z., R. Dubner, and Y. Shir, A novel behavioral model of neuropathic pain disorders produced in rats by partial sciatic nerve injury. Pain, 1990. 43: p. 205-218]; (iii) and the chronic constriction injury [Bennett, G. and Y. Xie, A peripheral mononeuropathy in rat that produces disorders of pain sensation like those seen in man. Pain, 1988. 33: p. 87-107]. The Bennett model was used, as described below.
[0000] Animals: Young adult, male Sprague Dawley rats (200-250 g) from Harlan were used. Upon receipt, animals were assigned unique identification numbers (tail marked) and housed 2-3 per cage in suspended polycarbonate rat cages with filter paper covering mesh shelf. Rats were acclimated for up to 7 days prior to surgery. During the period of acclimation, rats were examined on a regular basis, handled, and weighed to assure adequate health and suitability. Animals were maintained on a 12/12 light/dark cycle. The room temperature was maintained between 20 and 23 C with a relative humidity maintained between 30% and 70%. Chow and water were provided ad libitum for the duration of the study. In each test, animals were randomly assigned across treatment groups. Each treatment group contained at least ten animals. All animals were euthanized after the completion of the study.
Drugs: All compounds were suspended in 5% Tween80, 5% PEG in saline and administered orally at a dose volume of 1 ml/kg. In all experiments carbamazepine, per oral, was used as a positive control.
Apparatus: The apparatus consists of a cold plate (Ugo Basile Hot/Cold Plate) measuring 25 (w)×37 (d)×16 (h) cm with a 10 cm thick aluminum circular plate. Additionally, a clear Plexiglas cylinder measuring 20 (d)×25 (h) cm is placed on top of the plate. Neuropathic rats (7-8 days after surgical sciatic nerve ligation) were habituated to the testing room for at least 1 hr. Baseline responses were measured on the day prior to drug administration. Each animal was tested by placing it on the cold plate (set to 4 C) and the latency of paw withdrawal was recorded.
Surgery: Chronic constrictive nerve injury of the sciatic nerve was performed according to Bennett and Xie (1988). Specifically, rats were anesthetized with isoflurane (2% in air). The left hind flank was shaved and sterilized and the rat positioned on its side. The pelvic bone ridge was palpated and a vertical incision was made perpendicular to the long axis of the spine. The first layer of muscle was cut to expose the sciatic nerve. Retractors were used to open incision, centering the portion of the sciatic nerve to be ligated. The exposed nerve was carefully teased apart from the second layer of muscle, removing fascia lining. Once the nerve was freed, hooked forceps were carefully passed underneath the nerve in order to pass 5 cm lengths of 4.0 chromic gut suture under the nerve (sutures were pre-soaked in saline to ensure softness). Sutures were positioned superior to the point where the nerve branches. Each length of suture was used to make a loose ligation around the nerve (only tight enough to elicit a twitch). All sutures were within a 0.5 cm range of each other. The incision was closed in layers, using 4.0 silk sutures, and the skin was closed using sterile autoclips. Topical antibiotic ointment was applied to the sutured incision. All subjects received buprenorphine (0.05 mg/kg in a volume of 1 ml/kg, i.p) immediately before and after surgery. Each subject was monitored until it was awake and moving freely around the recovery chamber. Animals were then single-housed for the duration of the study.
Experimental Results
[0073] Experimental results for a representative compound of Formula I and Formula II, 3-(2,4-dichlorobenzyl)-2-methyl-N-(pentylsulfonyl)-3H-benzimidazole-5-carboxamide, are shown in FIGS. 1-4 .
[0074] All chemical groups recited herein are defined according to the disclosure of Yamasaki et al. in EP 0882718 B1.
[0075] Any of the compounds described herein can be administered as a prodrug to increase the activity, bioavailability, stability or otherwise alter the properties of the selected compound. A number of prodrug ligands are known.
[0076] The term “medicament” means a substance used in a method of treatment and/or prophylaxis of a subject in need thereof, wherein the substance includes, but is not limited to, a composition, a formulation, a dosage from, and the like, comprising a compound of Formula I or Formula II. It is contemplated that the use of a compound of a method of the invention in the manufacture of a medicament for the treatment of any of the conditions disclosed herein can be any of the compounds contemplated in any of the aspects of the invention, either alone or in combination with other compounds of the methods of the present invention.
[0077] The term “therapeutically effective amount” as used herein means an amount required to reduce symptoms of neuropathic pain in an individual. The dose will be adjusted to the individual requirements in each particular case. That dosage can vary within wide limits depending upon numerous factors such as the severity of the condition to be treated, the age and general health condition of the patient, other medicaments with which the patient is being treated, the route and form of administration and the preferences and experience of the medical practitioner involved. For oral administration, a daily or twice daily dosage of between about 0.1 and about 10 mg, including all values in between, such as 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, and 9.5, per day should be appropriate in monotherapy and/or in combination therapy. One twice daily dosage embodiment is between about 0.5 and about 7.5 mg twice per day. Another twice daily dosage embodiment is between 1.0 and about 6.0 mg twice per day. One of ordinary skill in treating conditions described herein will be able, without undue experimentation and in reliance on personal knowledge, experience, and the disclosures of this application, to ascertain a therapeutically effective amount of the compounds of the methods of the present invention for a given condition and patient. | Embodiments of the invention relate to the treatment of neuropathic pain in mammals. Embodiments of the invention include methods for treating neuropathic pain with benzimidazole derivatives with PPARgamma agonist activity, as well as methods for preparing medicaments used in such treatments of mammalian pain. | 2 |
FIELD OF THE INVENTION
[0001] The present invention relates generally to scooters, and more particularly to a body weight-activated scooter utilizing the principle of an overrunning clutch drive for generating forward motion.
BACKGROUND OF THE INVENTION
[0002] The world population, especially in Western societies, resides more and more in flat, smooth places (due to paving). Localities and areas that are not smooth and flat can be improved and developed into areas more suitable to the use of “wheeled feet”, to ease the task of the feet.
[0003] Lightweight, relatively inexpensive, small-wheeled, foot-operated devices for individual transport, recreation, and sports activity--exclusive of pedaled vehicles, such as bicycles—generally include scooters, skateboards, roller skates, and roller blades which are generally used by young children and youth. While the former two devices are operated with a foot action, pushing with a foot against a hard surface to create an opposing forward motion, the latter two devices are strapped directly to the feet of a user and are operated by combinations of foot and body action, similar to rapid walking performed with a swaying motion of the upper portion of the body, an activity generally unsuitable for older adults and elderly people with reduced physical abilities.
[0004] Thus there is a need for a relatively inexpensive, lightweight, yet sturdy-construction scooter which can support an adult user without undue physical exertion and which is activated by the use of body-weight force.
SUMMARY OF THE INVENTION
[0005] Accordingly, it is a principal object of the present invention to overcome the disadvantages of the prior art and to provide a body weight-activated scooter having at least one front wheel and at least one rear wheel attached on a frame, the scooter comprising:
at least one foot-rest pivotally attached at its forward portion to a fixed point on the frame and fixedly attached at its heelward portion to one end of a linking means so that a heelward portion of the at least one foot-rest is free to pivot up and down, and at least one drive train mounted on the frame for operation of the scooter, the at least one drive train comprising: at least one weight-vector wheel for controlled timing of forward motion of the scooter, and at least one overrunning clutch-drive connected to the at least one weight-vector wheel, the at least one overrunning clutch-drive providing sustained forward thrust, wherein when the at least one foot-rest is depressed by the body-weight force of a rider, the at least one drive train is activated via the linking means to produce the forward motion, the at least one overrunning clutch-drive being mechanically connected to the at least one rear wheel, the at least one linking means being firmly attached at its other end to at least one return tension means attached to the frame to enable continuous repetition of the operation of the at least one drive-train.
[0011] The scooter of the present invention, in a preferred embodiment thereof, is operated by the weight of the body through small, controlled, foot movements, either individually or together, which, when applied to at least one foot-rest or foot-supporting belt, moves the scooter forward. In effect, the scooter exploits the weight of the body while “walking” in place to generate a forward motion. When a user pauses between “steps”, the scooter coasts freely. To lengthen coasting motion, the user simply resumes the “walking” action and it is not necessary to use a push with a free foot against the ground or surface to regain momentum as is done with a children's scooter. The scooter is especially suited for use on flat, paved areas, such as city streets, sidewalks, broad plazas, and shopping and recreational centers since it is not motorized.
[0012] In a preferred embodiment of the invention, one side of a link-chain is connected to the heel portion of a foot-rest or foot-supporting belt; the second side of the link-chain is connected to an overrunning clutch, which operates at least one rear-drive wheel. The purpose of the overrunning clutch is to operate the drive-train which is automatically engaged in one direction, but freewheels in the other. A return spring returns the link-chain to its initial starting position.
[0013] Alternatively, a V-belt is used in place of a link-chain to operate the overrunning clutch. The tightness of the V-belt or link-chain allows a twofold pull and consequent saving of energy in the propulsion of the scooter. This allows for a higher speed of operation and reduced weight of the frame. In a preferred embodiment of the invention, the foot-rests are provided with skid-proof surfaces for greater traction. Alternatively, lighter-weight foot-supporting belts are provided instead of foot-rests for operating the scooter and resting the feet.
[0014] The system of the invention is adaptable for application in a four-wheeled chassis having two drive-wheels for the convenience of adults and people with physical limitations. It can also be used as a sports or recreational vehicle having two wheels, mounted at opposing ends of the dual foot-rest, one of which is a drive fitted with two overrunning clutches mounted one on each side of the drive-wheel and the other a freely-turning wheel to provide steering. In one embodiment of the invention, the device fits under a foot much like a skate shoe with an open heel. With the aid of intermediate wheels one can align a linking means, such as a link-chain above and behind the heels of the feet.
[0015] The invention is adaptable to accommodate add-ons to assist easy and correct movement of a link-chain in a number of ways, such as the addition of an idler wheel to reduce slack in the link-chain. Other add-ons, such as front and rear lights, warning lights and alarms, a speedometer, and an odometer are easily fitted to the scooter of the invention. Furthermore, small, relatively quiet, electric drives or motors can be added, for example, to automatically and more comfortably adjust the height of either the handlebars or the weight-vector wheels for different users and for different applications of the scooter of the invention.
[0016] An appropriate frame, as lightweight as possible, is necessary to optimize the stepping action of a user to drive the scooter forward. In a preferred embodiment of the invention, the scooter is constructed of a relatively lightweight material, such as plastic, aluminum, leather, and any similar lightweight structural material so it is convenient to use and saves exertion effort of a user.
[0017] The stepping action can be extended or shortened as needed by changing the height of the weight-vector wheel in relation to the ground and thus optimizing the placement of the body weight for maximizing either the power or speed of the scooter. The low center of gravity of the scooter provides for greater stability and control for users.
[0018] The scooter is intended for smooth, flat surfaces which will help people who have walking difficulties; only a small lifting of the heel of the foot is sufficient to create a driving “pulse”. The device of the invention, being simple in design, does not require a motor and is therefore relatively inexpensive to produce. It is also quiet in operation and pollution-free to the environment.
[0019] The key element of locomotion is the requirement that the pushing vector is optimized in relation to the gravitational vector so as to utilize the lowest center of gravity. The power of the foot pressure is applied as close as possible to the pressure vector. In a sports model embodiment of the invention, the pressing cycle is longer than in other applications.
[0020] The present invention, in a preferred embodiment thereof, optimizes the placement of the foot-rest close to the ground, thus providing the added advantage that it is easier for elderly users to alight or mount the scooter.
[0021] Other features and advantages of the invention will become apparent from the following drawings and descriptions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] For a better understanding of the invention in -regard to the embodiments thereof, reference is made to the following drawings, not shown to scale, in which numerals designate corresponding sections or objects throughout, and in which:
[0023] FIG. 1 is a schematic drawing of the initial stage of operation of components of the power train system of the invention in a preferred embodiment thereof,
[0024] FIG. 2 is a schematic drawing of the return stage of operation of the power train system from FIG. 1 ;
[0025] FIG. 3 is a top, schematic view of the layout, in accordance with a preferred embodiment of the invention, of the major components of a two-wheeled scooter adapted for sport users;
[0026] FIG. 4 is an exploded, detailed view of the embodiment of the two-wheeled scooter of FIG. 3 ;
[0027] FIG. 5 is top, schematic view of the layout, in accordance with another embodiment of the invention, of the major components of a four-wheeled scooter suitable for adult and recreational use;
[0028] FIG. 6 is an exploded, diagrammatic view of the embodiment of the four-wheeled scooter of FIG. 5 ; and
[0029] FIGS. 7 a and 7 b are side views illustrating the initial and return stages, respectively, in the operation of yet another embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0030] FIG. 1 is a schematic drawing of the initial stage of operation of components of the power train system of the invention in a preferred embodiment thereof. Since FIG. 1 is intended to illustrate only the power train system of the invention, the wheels, frame, and steering mechanisms of a scooter, which are known to those skilled in the art, are not shown (see FIG. 4 ).
[0031] One end of a linking means 12 , such as a bicycle-type link-chain or, alternatively, a V-belt, is attached at a node 16 to a foot-rest 18 which is rotatably attached at a forward node 28 of foot-rest 18 , such as by a hinge, so that the heelward portion of foot-rest 18 near node 16 is free to move up and down with the corresponding movement of link-chain 12 .
[0032] For convenience of description and for illustration purposes, linking means 12 is hereinafter referred to as link-chain 12 .
[0033] Link-chain 12 is linked to a weight-vector wheel 14 disposed above foot-rest 18 , then passes around and connects to an overrunning clutch 10 , and finally is secured at node 20 to return spring 22 which itself is fixedly connected at node 24 to a scooter frame (not shown). Forward node 28 is also mechanically connected to another part of the same frame. An overrunning clutch will automatically engage in one direction, but will freewheel in the other. In a preferred embodiment of the invention and by way of example, the overrunning clutch 10 is of the roller bearing type. The general symbols 9 represent a sampling of one of a number of roller bearings and ramps which are housed in an inner hub of overrunning clutch 10 and which allow movement of the roller bearings in only one direction (up the ramp), but acts as a stop in the other direction causing the clutch to freewheel.
[0034] Body-weight force of a user, represented by shoe 26 , operates the power train system of the invention to produce forward motion. Stepping action on foot-rest 18 creates “pulses” which rotate overrunning clutch 10 and moves link-chain 12 , as shown in FIG. 1 by arrows. The drive pulse is transmitted to at least one rear-drive wheel, indicated by the common axle 21 , when an incremental downward movement of the heel of a rider standing on at least one foot-rest 18 exerts foot pressure on the drive train. Thus, a downward pressure (indicated by arrow P 1 ) at the heel of shoe 26 on foot-rest 18 causes link-chain 12 to also move downward and counter-clockwise (arrow Q 1 ) around weight-vector wheel 14 thus rotating (arrow R 1 ) overrunning clutch 10 and providing thrust to at least one rear-drive wheel (not shown) attached to it through the common axle 21 , providing a forward motion to propel the scooter.
[0035] The counter-clockwise motion about weight-vector wheel 14 and overrunning clutch 10 of link-chain 12 pulls and extends return spring 22 creating a tension force. When foot-rest 18 reaches a pre-determined arc of motion d, it comes to rest at stopping position 29 . This arc of motion d is adjustable in accordance with the optimal functioning of the system of the invention and releases the pressure on overrunning clutch 10 which then freewheels, as explained heretofore.
[0036] FIG. 2 is a schematic drawing of the return stage of operation of the power train system shown in FIG. 1 . Overrunning clutch 10 is forced by the tension of return spring 22 to freewheel in a reverse, clockwise direction R 2 , thus returning return spring 22 to a state of rest while not producing any forward motion. Link-chain 12 , however, is drawn upward (as indicated by arrow P 2 ) at node 16 to wind clockwise (arrow Q 2 ) around weight-vector wheel 14 , thus lifting the heelward portion of foot-rest 18 upward into a ready position for another cycle of operation of the power train.
[0037] FIG. 3 is a top, schematic view of the layout of the major components of a two-wheeled scooter adapted for sport users and constructed in accordance with a preferred embodiment of the invention. The scooter 37 is shown in a schematic type view without reference to a frame or steering means to emphasize the inventive features.
[0038] One rear-drive wheel 30 is disposed on the same axle, represented by center line 21 , as a pair of overrunning clutches 10 which are mounted on both sides of rear wheel 30 and linked by link-chain 12 to a pair of weight-vector wheels 14 mounted on a common axis 15 supported by a vertical frame shaft (not shown) above twin foot-rests 18 . A steerable front wheel 32 is shown in FIG. 3 only for reference purposes in relation to the other described features in the layout of the invention.
[0039] FIG. 4 is an exploded, detailed view of the embodiment of the two-wheeled scooter of FIG. 3 . The scooter 37 is guided by handlebars 34 and turning post 36 connected by a height adjustment shaft 38 to front wheel 32 . A tightening means 40 is provided to hold the handlebars 34 at a designated height suitable for the user. The entire steering mechanism 36 , from handlebars 34 to front wheel 32 can be disassembled as shown in FIG. 4 for convenient storage of the scooter using standard mechanical fasteners, such as are well-known to those skilled in the art. Dot-and-dash lines are used to indicate re-assembly points and directions for attachment of the various components shown.
[0040] To provide maximum body-weight vector force, a T-bar 44 is connected to the scooter frame 46 via a vertical frame shaft 45 which can be varied in height to provide for differences in body-weight vector forces and optimize scooter performance by altering the center of gravity in relation to the body weight of a user. Controlled timing, by adjusting the gravity vector of the weight vector-wheel 14 , affects a change in the speed of travel and power of motion of a scooter.
[0041] Forward motion is optimized when the foot pressure applied by a user is as close as possible to the pressure vector in relation to a gravitational vector. The weight-vector wheels 14 are mounted on either side of T-bar 44 and linked by link-chain 12 to their respective overrunning clutches 10 disposed on the outer sides of rear drive-wheel 30 .
[0042] FIG. 5 is top, schematic view of the layout, in accordance with another embodiment of the invention, of the major components of a four-wheeled scooter suitable for adult and recreational use. (Additional features and further details are shown in FIG. 6 .)
[0043] The four-wheeled scooter 39 is provided with two overrunning clutches 10 , which are mounted on a common axle 29 with two fixed rear-drive wheels 30 to which they are mechanically connected. A pair of linking means, such as link-chains 12 are fixedly connected at nodes 16 to respective foot-platforms 18 and engage a pair of weight-vector wheels 14 , which are mounted on a supporting frame structure (not shown) above each respective foot-rest 18 and further linked to corresponding overrunning clutches 10 . After being partially wound around their respective overrunning clutches 10 , each of the other ends of each link-chain 12 are fixedly attached to return tension means, such as tension springs (not shown) which are anchored in the underside of the frame (not shown) of scooter 39 . The principle of operation of scooter 39 is as shown in FIGS. 1 and 2 and described hereinbefore. Two, steerable front wheels 32 for steering are controlled by handlebars 34 attached to a steering means 42 (see FIG. 6 ).
[0044] FIG. 6 is an exploded, detailed view of the embodiment of the four-wheeled scooter of FIG. 5 . In most respects, scooter 39 operates similarly to the embodiment of the invention of FIGS. 3 and 4 except for the distinctive feature of additional wheels and a more sophisticated steering mechanism 42 , including a turn-bar mechanism 48 as is known to those skilled in the art for operating both front wheels 32 in tandem when making a turn with scooter 39 . It should be noted that in actual assembly, the weight-vector wheels 14 are aligned above their respective rear-drive wheels 30 so that each, respective link-chain 12 is linked without slack around their respective overrunning clutches 10 to apply maximum torque to rear-drive wheels 30 when scooter 39 is operated. Due to the exploded view shown in FIG. 6 , the two link-chains 12 are not shown in full, but only partially shown at their respective ends where they are fixed at nodes 16 and 20 and arrows A-A and B-B indicate general continuations from end to end. A full, detailed layout of the link-chain connections is as shown in FIGS. 1 and 2 for each rear-drive wheel 30 .
[0045] FIGS. 7 a and 7 b are side views illustrating the initial and return stages, respectively, in the operation of yet another embodiment of the invention.
[0046] The overrunning clutch principle is applied to a self-propelled roller-skate type device 35 attached by a foot strap 50 to each shoe 26 of a user. In another embodiment of the invention (not shown), a shoe-like platform is an oversized, fixed feature which conveniently accommodates and holds a variety of user shoe sizes. In either embodiment, the foot of the user is strapped tightly to a shoe platform 54 or, alternatively, to a wide, foot-supporting belt (not shown) which replaces platform 54 . The belt embodiment of the invention is provided with a small-diameter rod or wheel disposed at the heel end of shoe 26 to maintain tension in the belt and control slack.
[0047] In operation, as shown in FIG. 7 a , the user's foot in shoe 26 presses down so that the heel of shoe 26 moves in a short arc downward as shown by the double-headed arrow. The link-chain 12 is thus pulled in a downward direction by body weight force applied via link-chain 12 to weight-vector wheel 14 which rotates counter-clockwise. Since weight-vector wheel 12 is linked to overrunning clutch 10 mounted on the axle of rear-drive wheel 52 , the overrunning clutch 10 also rotates counter-clockwise and causes rear-drive wheel 52 to also turn, moving device 35 forward. When the foot of a user comes to rest at the lowest point of the arc designated in FIG. 7 a by the double-headed arrow, the return tension spring 22 is fully stretched and begins to exert a counter-pulling force on link-chain 12 . Since this force causes overrunning clutch 10 to rotate in a clock-wise direction, it becomes disengaged from rear-drive wheel 52 and freewheels. When the heel of a user is raised away from shoe platform 54 at the downward end of a “walking” cycle as indicated in FIG. 7 b , shoe platform 54 becomes free to rise at its heelward end due to the reverse pull on link-chain 12 generated by tension spring 22 on link-chain 12 and this prepares the roller-skate type device 35 for another cycle of operation.
[0048] A rigid structure 56 both supports weight-vector wheel 14 disposed at an optimal height above shoe platform 54 to maximize body-weight force and provides a frame for the roller-skate type device 35 . Rigid structure 56 is made of rigid plastic although other suitable materials may be used. Notice the cutaway view of rigid structure 56 in FIG. 7 a which shows a metal support 58 embedded in the frame to provide greater safety and strength.
[0049] Having described the invention with regard to certain specific embodiments, it is to be understood that the description is not meant as a limitation, since further modifications may now suggest themselves to those skilled in the art, and it is intended to cover such modifications as fall within the scope of the appended claims. | A body weight-activated scooter operated by the weight of the body through small, controlled, foot movements. The scooter has at least one front wheel and at least one rear wheel attached on a frame, with a foot-rest pivotally attached at its forward portion to a fixed point on the frame and fixedly attached at its heelward portion to one end of a linking means so that the heelward portion of the foot-rest is free to pivot up and down. The scooter has a drive train mounted on the frame comprising a weight-vector wheel connected to an overrunning clutch-drive which is mechanically connected to the rear wheel, the overrunning clutch-drive providing sustained forward thrust when the foot-rest is depressed, thus activating the drive train via the linking means to produce forward motion. The linking means is firmly attached at its other end to a return tension means attached to the frame, enabling continuous, repetitive scooter operation. | 1 |
FIELD OF THE INVENTION
[0001] The invention relates to catalyst systems that include triple-decker bimetallic complexes having a delocalized dianionic ligand. The catalysts are useful for polymerizing olefins.
BACKGROUND OF THE INVENTION
[0002] While Ziegler-Natta catalysts are a mainstay for polyolefin manufacture, single-site (metallocene and non-metallocene) catalysts represent the industry's future. These catalysts are often more reactive than Ziegler-Natta catalysts, and they often produce polymers with improved physical properties.
[0003] Since the mid-1980s, scientists have become increasingly interested in bimetallic metallocenes, and in particular, how two metal centers communicate with each other via electronic and through-space interactions (see, e.g., Reddy et al. Organometallics 8 (1989) 2107). Cooperative effects are most likely when the two metal centers are electronically coupled through a conjugated pi-electron system. Ultimately, understanding cooperative effects should let polyolefin manufacturers fine-tune polymer properties by varying catalyst structure.
[0004] U.S. Pat. No. 6,414,162 describes bimetallic complexes that derive from dianionic indenoindolyl ligands. These complexes can include two metals bonded to the dianionic indenoindolyl ligand. While one of the anions is delocalized and provides pi bonding to a metal, the other is on the nitrogen atom and provides sigma bonding to the second metal. Pending application Ser. No. 10/308,842, filed Dec. 3, 2002, discloses a bimetallic complex with two linked indenoindolyl groups.
[0005] Triple-decker complexes, where two metals have a ligand between them that can provide pi bonding, have been known since the late 1970s (see, e.g., J. Am. Chem. Soc . 98 (1976) 3219 ; J. Am. Chem. Soc . 100 (1978) 999 ; J. Am. Chem. Soc . 100 (1978) 7429 and Angew. Chem., Int. Ed. Engl . 16 (1977) 1), but there has been no indication that these complexes might be suitable for polymerizing olefins.
[0006] Delocalized dianionic ligands are known. In J. Am. Chem. Soc . 122 (2000) 5278, a series of various porphyrins are synthesized. Trimethylenemethane based ligands have been used ( J. Am. Chem. Soc . 119 (1997) 343) to prepare monometallic zirconium complexes and it was demonstrated that these complexes could be used to polymerize ethylene. Other delocalized dianionic ligands are reported in J. Am. Chem. Soc . 122 (2000) 5278 ; J. Am. Chem. Soc . 119 (1997) 343 ; J. Am. Chem. Soc . 82 (1960) 3784 ; J. Chem. Soc. Part B (1971) 904 ; J. Am. Chem. Soc . 87 (1965) 128; ibid., 5508 and Chem. Ber . 117(1984) 1069.
[0007] Despite the considerable work that has been done in the area of olefin polymerization, there is a need for improved catalysts. Because of the wide variety of polyolefin end uses, there is also a need for catalysts that can be easily modified to give polyolefins with different property profiles.
SUMMARY OF THE INVENTION
[0008] The invention relates to catalysts which comprise an activator and a triple-decker bimetallic complex. The complex includes two Group 3-10 transition metals and a delocalized dianionic ligand pi-bonded to each of the metals. Finally, the complex includes two or more ancillary ligands bonded to each metal that satisfy the valence of the metals.
[0009] Catalysts of the invention are versatile. The use of two metals gives an extra dimension for modification of the catalysts. The behavior of the catalysts can be modified by choice of each metal, by the choice of the dianionic ligand or by choice of the ancillary ligands. The invention provides a new way to make a large variety of catalyst systems. As end uses continue to evolve that require new and different polyolefins, it is valuable to have a catalyst system that can be easily modified.
DETAILED DESCRIPTION OF THE INVENTION
[0010] Catalysts of the invention comprise an activator and a bimetallic complex. The complex includes two metal atoms, which may be the same or different, from Groups 3-10. Preferably, the complexes include two Group 4-6 transition metals. Most preferred are complexes that include two Group 4 transition metal atoms, such as titanium or zirconium.
[0011] The bimetallic complex also includes a delocalized dianionic ligand pi bonded to each of the metals and two or more ancillary ligands bonded to each metal that satisfy the valence of the metals. The two metals are bonded to, and separated from each other by, the delocalized dianionic ligand. One route to catalyst deactivation can be the interaction of the metals. This separation of the two metals by the dianionic ligand helps to prevent intramolecular deactivation.
[0012] The dianionic ligand is delocalized. By “delocalized,” we mean that the two negative charges of the dianion are distributed over a planar or substantially planar system of several or many atoms, preferably a conjugated system of pi-electrons. Exemplary delocalized dianionic ligands are:
[0013] Preferred dianions include the trimethylenemethane dianion, cyclobutadiene dianion, cyclooctatetraene dianion, porphyrin dianion, biphenylene dianion, tetraphenylene dianion, [12]annulene dianion, and phthalocyanine dianion. The trimethylenemethane dianion and cyclobutadiene dianion are especially preferred (see modeling calculations, Tables 1 and 2).
[0014] Delocalized dianionic ligands can be made by well-known synthetic paths. In J. Am. Chem. Soc . 122 (2000) 5278, a series of various porphyrins are synthesized. Trimethylenemethane-based ligands have been used ( J. Am. Chem. Soc . 119 (1997) 343) to prepare monometallic zirconium complexes. Boat-shaped cyclooctatetraene is readily converted to a planar 10-pi electron dianion by a two-electron reduction with an alkali metal ( J. Am. Chem. Soc . 82 (1960) 3784). Similarly, the planar 14-pi electron dianion from [12]annulene has been reported ( J. Chem. Soc. Part B (1971) 904). The biphenylene dianion has also been generated ( J. Am. Chem. Soc . 87 (1965) 128; ibid., 5508 ; Chem. Ber . 117 (1984) 1069). Cyclobutadiene, a short-lived compound at best, can nonetheless be generated by exposing cyclobutadieneiron tricarbonyl (see Org. Synth . 50 (1970) 21, 37) to lead tetraacetate or ceric ammonium nitrate (see J. Am. Chem. Soc . 87 (1965) 131, 3253; 89 (1967) 3080).
[0015] In addition to the delocalized dianionic ligand, the bimetallic complex includes ancillary ligands that are bonded to each metal. Each metal has two or more neutral or anionic ancillary ligands that satisfy the valence of the metals. The ancillary ligands can be labile or polymerization-stable, but usually at least one labile ligand (such as halides, alkoxys, aryloxys, alkyls, alkaryls, aryls, dialkylaminos, or the like) is present. Particularly preferred labile ligands are halides, alkyls, and alkaryls (e.g., chloride, methyl, benzyl). Suitable polymerization-stable ligands include cyclopentadienyl, indenyl, fluorenyl, boraaryl, pyrrolyl, indenoindolyl, and the like.
[0016] Preferably, the bimetallic complex has the structure:
[0017] wherein each M is independently a Group 3 to 10 transition metal; each L is independently selected from the group consisting of halide, alkoxy, siloxy, alkylamino, and C 1 -C 30 hydrocarbyl; each L′ is selected from the group consisting of substituted or unsubstituted cyclopentadienyl, fluorenyl, indenyl, boraaryl, pyrrolyl, azaborolinyl, and indenoindolyl; L″ is a delocalized dianionic ligand; y is 0 or 1; and (x+y)−1 satisfies the valence of M.
[0018] Exemplary structures:
[0019] Any convenient source of the transition metal can be used to make the bimetallic complex. The transition metal source conveniently has labile ligands such as halide or dialkylamino groups that are easily displaced by indenoindolyl anions. Examples are halides (e.g., TiCl 4 , ZrCl 4 ), alkoxides, amides, and the like. In order to make a bimetallic complex, preferably, two or more equivalents of transition metal source are reacted with 1 equivalent of dianion. When the complex is to include additional polymerization-stable ligands, it is convenient if they are already present on the transition metal source. For example, cylopentadienylzirconium trichloride or fluorenyltitanium trichloride could be used as the transition metal source and reacted with the dianion if a cyclopentadienyl or fluorenyl ligand were desired in the bimetallic complex.
[0020] Catalysts of the invention include, in addition to the bimetallic complex, an activator. The activator helps to ionize the bimetallic complex and activate the catalyst. Suitable activators are well known in the art. Examples include alumoxanes (methyl alumoxane (MAO), PMAO, ethyl alumoxane, diisobutyl alumoxane), alkylaluminum compounds (triethylaluminum, diethyl aluminum chloride, trimethyl-aluminum, triisobutyl aluminum), and the like. Suitable activators include acid salts that contain non-nucleophilic anions. These compounds generally consist of bulky ligands attached to boron or aluminum. Examples include lithium tetrakis(pentafluorophenyl)-borate, lithium tetrakis(pentafluorophenyl)aluminate, anilinium tetrakis(pentafluorophenyl)borate, and the like. Suitable activators also include organoboranes, which include boron and one or more alkyl, aryl, or aralkyl groups. Suitable activators include substituted and unsubstituted trialkyl and triarylboranes such as tris(pentafluorophenyl)borane, triphenylborane, tri-n-octylborane, and the like. These and other suitable boron-containing activators are described in U.S. Pat. Nos. 5,153,157, 5,198,401, and 5,241,025, the teachings of which are incorporated herein by reference. Suitable activators also include aluminoboronates—reaction products of alkyl aluminum compounds and organoboronic acids—as described in U.S. Pat. Nos. 5,414,180 and 5,648,440, the teachings of which are incorporated herein by reference. Alumoxane activators, such as MAO, are preferred.
[0021] The optimum amount of activator needed relative to the amount of bimetallic complex depends on many factors, including the nature of the complex and activator, the desired reaction rate, the kind of polyolefin product, the reaction conditions, and other factors. Generally, however, when the activator is an alumoxane or an alkyl aluminum compound, the amount used will be within the range of about 0.01 to about 5000 moles, preferably from about 10 to about 500 moles, and more preferably from about 10 to about 200 moles, of aluminum per total moles of transition metal, M. When the activator is an organoborane or an ionic borate or aluminate, the amount used will be within the range of about 0.01 to about 5000 moles, preferably from about 0.1 to about 500 moles, of activator per mole of M. The activator can be combined with the complex and added to the reactor as a mixture, or the components can be added to the reactor separately.
[0022] The catalyst can be used with a support such as silica, alumina, titania, or the like. Silica is preferred. The support is preferably treated thermally, chemically, or both prior to use to reduce the concentration of surface hydroxyl groups. Thermal treatment consists of heating (or “calcining”) the support in a dry atmosphere at elevated temperature, preferably greater than about 100° C., and more preferably from about 150 to about 600° C., prior to use. A variety of different chemical treatments can be used, including reaction with organo-aluminum, -magnesium, -silicon, or -boron compounds. See, for example, the techniques described in U.S. Pat. No. 6,211,311, the teachings of which are incorporated herein by reference.
[0023] The catalyst is particularly valuable for polymerizing olefins. Preferred olefins are ethylene and C 3 -C 20 α-olefins such as propylene, 1-butene, 1-hexene, 1-octene, and the like. Mixtures of olefins can be used. Ethylene and mixtures of ethylene with C 3 -C 10 α-olefins are especially preferred.
[0024] A wide variety of olefin polymerization processes can be used. Preferred processes are slurry, bulk, solution, and gas-phase proceses. A slurry or gas-phase process is preferably used. Suitable methods for polymerizing olefins using the catalysts of the invention are described, for example, in U.S. Pat. Nos. 5,902,866, 5,637,659, and 5,539,124, the teachings of which are incorporated herein by reference.
[0025] The polymerizations can be performed over a wide temperature range, such as about −30° C. to about 280° C. A more preferred range is from about 30° C. to about 180° C.; most preferred is the range from about 60° C. to about 100° C. Olefin partial pressures normally range from about 0.1 MPa to about 350 MPa. More preferred is the range from about 0.1 MPa to about 7 MPa.
[0026] Catalyst concentrations used for the olefin polymerization depend on many factors. Preferably, however, the concentration ranges from about 0.01 micromoles per liter to about 100 micromoles per liter. Polymerization times depend on the type of process, the catalyst concentration, and other factors. Generally, polymerizations are complete within several seconds to several hours.
[0027] The following examples merely illustrate the invention. Those skilled in the art will recognize many variations that are within the spirit of the invention and scope of the claims.
EXAMPLE 1
[0028] Lithium metal (13.9 mg; 2 mmol) is added to 10 mL of dry hexane in a round bottom flask equipped with dry ice condenser. The solution is cooled with a dry ice bath and 104 mg (1 mmol) cyclooctatetraene is added to the stirring solution. The mixture is stirred for 6 hours and warmed to room temperature. It is then added via cannula to a stirring mixture of 525 mg (2 mmol) of cyclopentadienylzirconium trichloride in tetrahydrofuran. The mixture is stirred 6 hours at room temperature and volatiles removed in vacuo. The residue is extracted with toluene to give a solution of the organometallic complex. This solution can be used “as is” for polymerizing olefins. The expected product is the bimetallic complex 1.
EXAMPLE 2
Ethylene Polymerization
[0029] A one-liter, stainless-steel reactor is charged with toluene (500 mL) and polymethalumoxane (2.2 mL of 4.14 M solution of PMAO in toluene, Al/Ti=2000). The reactor is charged with ethylene to 350 psig, and the contents are heated to 70° C. An aliquot of the toluene solution of the bimetallic complex 1 (containing 1.0 mg of complex) from Example 1 is injected into the reactor to start the polymerization. Ethylene is supplied on demand to keep the reactor pressure constant at 350 psig. After about 1 hour, the reactor is vented. The resulting product should be polyethylene.
Molecular Modeling Study
[0030] Additional evidence for the suitability of triple-decker bimetallic complexes with delocalized dianions as ligands for catalysts comes from molecular modeling studies. All calculations have been performed with complete geometry optimization using the DFT model B3LYP with the LACVP** pseudopotential basis set as incorporated into the TITAN™ software package.
[0031] To estimate the effect of ligands (L and L′) on the relative stability of the zirconocenium active sites, we are using the relative enthalpy (ΔΔH f ) of the reaction:
[0032] compared with the enthalpy of a standard process in which the zirconium is bonded to two cyclopentadienyl ligands:
[0033] According to these estimates (Table 1), the cyclobutadienyl, cyclooctatatetraenyl and trimethylenemethyl dianionic ligands should stabilize an electrophilic active site more effectively compared with a cyclopentadienyl ligand.
TABLE 1 Complex ΔΔH f , kcal/mole Cp 2 ZrMeEt 0 L″ = cyclobutadienyl dianion −3 L″ = cyclooctatetraenyl dianion −10 L″ = trimethylenemethyl dianion −5
[0034] The increased stability of the active site for the bimetallic complexes with dianionic ligands permits a high concentration of active sites in the polymerization process, which should result in a more active catalyst at low levels of expensive activator such as MAO.
[0035] The increased stability of the zirconocenium cation in the triple-decker complexes should have relatively little impact on its reactivity toward ethylene as characterized by the calculated heat of interaction upon pi-complexation (Table 2). The calculations predict about the same reactivity as the bis(Cp) control case for both the cyclobutadienyl dianion and the trimethylenemethyl dianion. Bimetallic complexes from the dianionic cyclooctatetraene ligand should be somewhat less reactive (8 kcal/mol) compared with the control case.
TABLE 2 Relative heat of interaction of Active site active site with ethylene, kcal/mol Cp 2 ZrEt+ 0 L″ = cyclobutadienyl dianion −1 L″ = cyclooctatetraenyl dianion 8 L″ = trimethylenemethyl dianion 0
[0036] The preceding examples are meant only as illustrations. The following claims define the invention. | Catalysts useful for polymerizing olefins are disclosed. The catalysts comprise an activator and a triple-decker bimetallic complex. The complex includes two Group 3-10 transition metals and a delocalized dianionic ligand that is pi-bonded to each of the metals. The behavior of the catalysts can be modified by choice of each metal, by the choice of the dianionic ligand, or by choice of the ancillary ligands. The invention provides a new way to make a large variety of catalyst systems. | 2 |
This application is a continuation-in-part application of 09/020,231 filed on Feb. 6, 1998 now abandoned and claims the benefit under 35 USC §119(e) of U.S. Provisional Application for Patent No. 60/037,517 filed Feb. 10, 1997 and U.S. Provisional Application for Patent No. 60/055,153, filed Aug. 8, 1997, the entire contents of which are hereby incorporated by reference.
TECHNICAL FIELD
This invention relates to the field of antivirals and in particular to derivatives of acyclic nucleosides useful against herpes and retroviral infections and methods for their manufacture and novel intermediates.
BACKGROUND OF THE INVENTION
The practical utility of many acyclic nucleosides is limited by their relatively modest pharmacokinetics. A number of prodrug approaches have been explored in an effort to improve the bioavailability of acyclic nucleosides in general. One of these approaches involves the preparation of ester derivatives, particularly aliphatic esters, of one or more of the hydroxy groups on the acyclic side chain.
European patent EP 165 289 describes the promising antiherpes agent 9-[4-hydroxy-(2-hydroxymethyl)butyl]guanine, otherwise known as H2G. European patent EP 186 640 discloses 6-deoxy H2G. European patent EP 343 133 discloses that these compounds, particularly the R-(−) enantiomer, are additionally active against retroviral infections such as HIV. Various derivatives of H2G, such as phosphonates, aliphatic esters (for example, the diacetate and the dipropionate) and ethers of the hydroxy groups on the acyclic side chain are disclosed in EP 343 133. This patent also discloses methods for the preparation of these derivatives comprising the condensation of the acyclic side chain to the N-9 position of a typically 6-halogenated purine moiety or, alternatively, the imidazole ring closure of a pyrimidine or furazano-[3,4-d]-pyrimidine moeity or the pyrimidine ring closure of an imidazole moiety, where the acyclic side chain is already present in the precursor pyrimidine or imidazole moiety, respectively. In the broadest description of each of these methods the acyclic side chain is pre-derivatised but individual examples also show a one-step diacylation of H2G with acetic or proprionic anhydride and DMF.
Harnden, et al., J. Med. Chem. 32, 1738 (1989) investigated a number of short chain aliphatic esters of the acyclic nucleoside 9-[4-hydroxy-(3-hydroxymethyl)butyl]guanine, otherwise known as penciclovir, and its 6-deoxy analog. Famciclovir, a marketed antiviral agent, is the diacetyl derivative of 6-deoxy penciclovir.
Benjamin, et al., Pharm. Res. 4 No. 2, 120 (1987) discloses short chain aliphatic esters of 9-[(1,3-dihydroxy-2-propoxy)-methyl]guanine, otherwise known as ganciclovir. The dipropionate ester is disclosed to be the preferred ester.
Lake-Bakaar, et al., discloses in Antimicrob. Agents Chemother. 33 No. 1, 110-112 (1989) diacetate and dipropionate derivatives of H2G and monoacetate and diacetate derivatives of 6-deoxy H2G. The diacetate and dipropionate derivatives of H2G are reported to result in only modest improvements in bioavailability relative to H2G.
International patent application WO94/24134, published Oct. 27, 1994, discloses aliphatic ester prodrugs of the 6-deoxy N-7 analog of ganciclovir, including the di-pivaloyl, di-valeroyl, mono-valeroyl, mono-oleoyl and mono-stearoyl esters.
International patent application WO93/07163, published Apr. 15, 1993 and International patent application WO94/22887, published Oct. 13, 1994, both disclose mono-ester derivatives of nucleoside analogs derived from mono-unsaturated C18 or C20 fatty acids. U.S. Pat. No. 5,216,142, issued Jun. 1, 1993, also discloses long chain fatty acid mono-ester derivatives of nucleoside analogs.
A second approach to providing prodrugs of acyclic nucleosides involves the preparation of amino acid esters of one or more of the hydroxy groups on the acyclic side chain. European patent EP 99 493 discloses generally amino acid esters of acyclovir and European patent application EP 308 065, published Mar. 22, 1989, discloses the valine and isoleucine esters of acyclovir.
European patent application EP 375 329, published Jun. 27, 1990, discloses amino acid ester derivatives of ganciclovir, including the di-valine, di-isoleucine, di-glycine and di-alanine ester derivatives. International patent application WO95/09855, published Apr. 13, 1995, discloses amino acid ester derivatives of penciclovir, including the mono-valine and di-valine ester derivatives.
DE 19526163, published Feb. 1, 1996 and U.S. Pat. No. 5,543,414 issued Aug. 6, 1996, disclose achiral amino acid esters of ganciclovir.
European patent application EP 694 547, published Jan. 31, 1996, discloses the mono-L-valine ester of ganciclovir and its preparation from di-valyl-ganciclovir.
European patent application EP 654 473, published May 24, 1995, discloses various bis amino acid ester derivatives of 9-[(1′,2′-bishydroxymethyl)-cyclopropan-1′yl]methylguanine.
International patent application WO95/22330, published Aug. 24, 1995, discloses aliphatic esters, amino acid esters and mixed acetate/valinate esters of the acyclic nucleoside 9-[3,3-dihydroxymethyl-4-hydroxy-but-1-yl]guanine. This reference discloses that bioavailability is reduced when one of the valine esters of the trivaline ester derivative is replaced with an acetate ester.
BRIEF DESCRIPTION OF THE INVENTION
We have found that diester derivatives of H2G bearing specific combinations of an amino acid ester and a fatty acid ester are able to provide significantly improved oral bioavailability relative to the parent compound (H2G). In accordance with a first aspect of the invention there is thus provided novel compounds of the formula I
wherein
a) R 1 is —C(O)CH(CH(CH 3 ) 2 )NH 2 or —C(O)CH(CH(CH 3 )CH 2 CH 3 )NH 2 and R 2 is —C(O)C 3 -C 21 saturated or monounsaturated, optionally substituted alkyl; or
b) R 1 is —C(O)C 3 -C 21 saturated or monounsaturated, optionally substituted alkyl and R 2 is —C(O)CH(CH(CH 3 ) 2 )NH 2 or —C(O)CH(CH(CH 3 )CH 2 CH 3 )NH 2 ; and R 3 is OH or H;
or a pharmaceutically acceptable salt thereof.
The advantageous effect on oral bioavailability of the mixed fatty acid and amino acid esters of the invention is particularly unexpected in comparison to the oral bioavailability of the corresponding fatty acid esters. Based on the results using a urinary recovery assay (Table 1A) or a plasma drug assay (Table 1B) of H2G from rats, neither the mono or di-fatty acid esters of H2G provide any improvement in oral bioavailability relative to the parent compound H2G. Indeed the di-stearate derivative provided significantly lower bioavailability than the parent, indicating that a stearate ester may be detrimental for improving oral bioavailability of H2G. Converting one or both of the hydroxyls in certain other acyclic nucleoside analogues to the corresponding valine or di-valine ester has been reported to improve bioavailability. Conversion of H2G to the coresponding mono- or di-valyl ester derivatives produced similar improvement in bioavailability relative to the parent compound. Given that fatty acid derivatives of H2G are shown to be detrimental for improving bioavailability, it was unexpected that a mixed amino acid/fatty acid diester derivative of H2G would provide improved or comparable oral bioavailability to that of the valine diester derivative of H2G, based on urine recovery and plasma drug assays, respectively.
TABLE 1A
R 1 group
R 2 group
Bioavailability*
hydrogen
hydrogen
8%
hydrogen
stearoyl
12%
stearoyl
stearoyl
1%
valyl
hydrogen
29%
valyl
valyl
36%
valyl
stearoyl
56%
*see Biological Example 1 below for details
TABLE 1B
R 1 group
R 2 group
Bioavailability #
hydrogen
hydrogen
3.8%
hydrogen
stearoyl
1.9%
stearoyl
stearoyl
0%
valyl
hydrogen
31.3%
valyl
valyl
35.0%
valyl
stearoyl
29%
#see Biological Example 2 below for details
The invention also provides pharmaceutical compositions comprising the compounds of Formula I and their pharmaceutically acceptable salts in conjunction with a pharmaceutically acceptable carrier or diluent. Further aspects of the invention include the compounds of Formula I and their pharmaceutically acceptable salts for use in therapy and the use of these compounds and salts in the preparation of a medicament for the treatment or prophylaxis of viral infection in humans or animals.
The compounds of the invention are potent antivirals, especially against herpes infections, such as those caused by Varicella zoster virus, Herpes simplex virus types 1 & 2, Epstein-Barr virus, Herpes type 6 (HHV-6) and type 8 (HHV-8). The compounds are particularly useful against Varicella zoster virus infections such as shingles in the elderly including post herpetic neuralgia or chicken pox in the young where the duration and severity of the disease can be reduced by several days. Epstein Barr virus infections amenable to treatment with the compounds include infectious mononucleosis/glandular fever which has previously not been treatable but which can cause many months of scholastic incapacity amongst adolescents.
The compounds of the invention are also active against certain retroviral infections, notably SIV, HIV-1 and HIV-2, and against infections where a transactivating virus is indicated.
Accordingly a further aspect of the invention provides a method for the prophylaxis or treatment of a viral infection in humans or animals comprising the administration of an effective amount of a compound of Formula I or its pharmaceutically acceptable salt to the human or animal.
Advantageously group R 3 is hydroxy or its tautomer ═O so that the base portion of the compounds of the invention is the naturally occuring guanine, for instance in the event that the side chain is cleaved in vivo. Alternatively, R 3 may be hydrogen thus defining the generally more soluble 6-deoxy derivative which can be oxidised in vivo (e.g. by xanthine oxidase) to the guanine form.
The compound of formula I may be present in racemic form, that is a mixture of the 2R and 2S isomers. Preferably, however, the compound of formula I has at least 70%, preferably at least 90% R form, for example greater than 95%. Most preferably the compound of formula I is enantiomerically pure R form.
Preferably the amino acid of group R 1 /R 2 is derived from an L-amino acid.
Preferably the fatty acid of group R 1 /R 2 has in total an even number of carbon atoms, in particular, decanoyl (C 10 ), lauryl (C 12 ), myristoyl (C 14 ), palmitoyl (C 16 ), stearoyl (C 18 ) or eicosanoyl (C 20 ). Other useful R 1 /R 2 groups include butyryl, hexanoyl, octanoyl or behenoyl (C 22 ). Further useful R 1 /R 2 groups include those derived from myristoleic, myristelaidic, palmitoleic, palmitelaidic, n6-octadecenoic, oleic, elaidic, gandoic, erucic or brassidic acids. Monounsaturated fatty acid esters typically have the double bond in the trans configuration, preferably in the ω-6, ω-9 or ω11 position, dependent upon their length. Preferably the R 1 /R 2 group is derived from a fatty acid which comprises a C 9 to C 17 saturated, or n:9 monounsaturated, alkyl.
The saturated or unsaturated fatty acid or R 1 /R 2 may optionally be substituted with up to five similar or different substituents independently selected from the group consisting of such as hydroxy, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, C 1 -C 6 alkoxy C 1 -C 6 alkyl, C 1 -C 6 alkanoyl, amino, halo, cyano, azido, oxo, mercapto and nitro, and the like.
Most preferred compounds of the formula I are those where R 1 is —C(O)CH(CH(CH 3 ) 2 )NH 2 or —C(O)CH(CH(CH 3 )CH 2 CH 3 )NH 2 and R 2 is —C(O)C 9 -C 17 saturated alkyl.
The term “lower alkyl” as used herein refers to straight or branched chain alkyl radicals containing from 1 to 7 carbon atoms including, but not limited to, methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, t-butyl, n-pentyl, 1-methylbutyl, 2,2-dimethylbutyl, 2-methylpentyl, 2,2-dimethylpropyl, n-hexyl and the like.
The term “alkanoyl” as used herein refers to R 20 C(O)— wherein R 20 is a loweralkyl group.
The term “alkoxy” as used herein refers to R 21 O— wherein R 21 is a loweralkyl group.
The term “alkoxyalkyl” as used herein refers to an alkoxy group appended to a loweralkyl radical.
The term “N-protecting group” or “N-protected” as used herein refers to those groups intended to protect the N-terminus of an amino acid or peptide or to protect an amino group against undesirable reactions during synthetic procedures. Commonly used N-protecting groups are disclosed in Greene, “Protective Groups in Organic Synthesis” (John Wiley & Sons, New York, 1981), which is hereby incorporated by reference. N-protecting groups include acyl groups such as formyl, acetyl, propionyl, pivaloyl, t-butylacetyl, 2-chloroacetyl, 2-bromoacetyl, trifluoracetyl, trichloroacetyl, phthalyl, o-nitrophenoxyacetyl, α-chlorobutyryl, benzoyl, 4-chlorobenzoyl, 4-bromobenzoyl, 4-nitrobenzoyl, and the like; sulfonyl groups such as benzenesulfonyl, p-toluenesulfonyl, and the like, carbamate forming groups such as benzyloxycarbonyl, p-chlorobenzyloxycarbonyl, p-methoxybenzyloxycarbonyl, p-nitrobenzyloxycarbonyl, 2-nitrobenzyloxycarbonyl, p-bromobenzyloxycarbonyl, 3,4-dimethoxybenzyloxycarbonyl, 4-methoxybenzyloxycarbonyl, 2-nitro-4,5-dimethoxybenzyloxycarbonyl, 3,4,5-trimethoxybenzyloxycarbonyl, 1-(p-biphenylyl)-1-methylethoxycarbonyl, α,α-dimethyl-3,5-dimethoxybenzyloxycarbonyl, benzhydryloxycarbonyl, t-butoxycarbonyl, diisopropylmethoxycarbonyl, isopropyloxycarbonyl, ethoxycarbonyl, methoxycarbonyl, allyloxycarbonyl, 2,2,2-trichloroethoxycarbonyl, phenoxycarbonyl, 4-nitrophenoxycarbonyl, fluorenyl-9-methoxycarbonyl, cyclopentyloxycarbonyl, adamantyloxycarbonyl, cyclohexyloxycarbonyl, phenylthiocarbonyl, and the like; alkyl groups such as benzyl, triphenylmethyl, benzyloxymethyl and the like; and silyl groups such as trimethylsilyl and the like. Favoured N-protecting groups include formyl, acetyl, benzoyl, pivaloyl, t-butylacetyl, phenylsulfonyl, benzyl, t-butoxycarbonyl (BOC) and benzyloxycarbonyl (Cbz).
The term “O-protecting group” or “hydroxy-protecting group” or “—OH protecting group” as used herein refers to a substituent which protects hydroxyl groups against undesirable reactions during synthetic procedures such as those O-protecting groups disclosed in Greene, “Protective Groups In Organic Synthesis,” (John Wiley & Sons, New York (1981)). O-protecting groups comprise substituted methyl ethers, for example, methoxymethyl, benzyloxymethyl, 2-methoxyethoxymethyl, 2-(trimethylsilyl)ethoxymethyl, t-butyl, benzyl and triphenylmethyl; tetrahydropyranyl ethers; substituted ethyl ethers, for example, 2,2,2-trichloroethyl; silyl ethers, for example, trimethylsilyl, t-butyldimethylsilyl and t-butyldiphenylsilyl; and esters prepared by reacting the hydroxyl group with a carboxylic acid, for example, acetate, propionate, benzoate and the like.
The term “activated ester derivative” as used herein refers to acid halides such as acid chlorides, and activated esters including, but not limited to, formic and acetic acid derived anhydrides, anhydrides derived from alkoxycarbonyl halides such as isobutyloxycarbonylchloride and the like, N-hydroxysuccinimide derived esters, N-hydroxyphthalimide derived esters, N-hydroxybenzotriazole derived esters, N-hydroxy-5-norbornene-2,3-dicarboxamide derived esters, 2,4,5-trichlorophenyl derived esters, sulfonic acid derived anhydrides (for example, p-toluenesulonic acid derived anhydrides and the like) and the like.
Preferred compounds of formula I include:
(R)-9-[2-(butyryloxymethyl)-4-(L-isoleucyloxy)butyl]guanine,
(R)-9-[2-(4-acetylbutyryloxymethyl)-4-(L-isoleucyloxy)butyl]guanine,
(R)-9-[2-(hexanoyloxymethyl)-4-(L-isoleucyloxy)butyl]guanine,
(R)-9-[4-(L-isoleucyloxy)-2-(octanoyloxymethyl)butyl]guanine,
(R)-9-[4-(L-isoleucyloxy)-2-(decanoyloxymethyl)butyl]guanine,
(R)-9-[4-(L-isoleucyloxy)-2-(dodecanoyloxymethyl)butyl]guanine,
(R)-9-[4-(L-isoleucyloxy)-2-(tetradecanoyloxymethyl)butyl]guanine,
(R)-9-[4-(L-isoleucyloxy)-2-(hexadecanoyloxymethyl)butyl]guanine,
(R)-9-[4-(L-isoleucyloxy)-2-(octadecanoyloxymethyl)butyl]guanine,
(R)-9-[2-(eicosanoyloxymethyl)-4-(L-isoleucyloxy)butyl]guanine,
(R)-9-[2-(docosanoyloxymethyl)-4-(L-isoleucyloxy)butyl]guanine,
(R)-9-[4-(L-isoleucyloxy)-2-((9-tetradecenoyl)oxymethyl)butyl]guanine,
(R)-9-[2-((9-hexadecenoyl)oxymethyl)-4-(L-isoleucyloxy)butyl]guanine,
(R)-9-[4-(L-isoleucyloxy)-2-((6-octadecenoyl)oxymethyl)butyl]guanine,
(R)-9-[4-(L-isoleucyloxy)-2-((9-octadecenoyl)oxymethyl)-butyl]guanine,
(R)-9-[2-((11-eicosanoyl)-oxymethyl)-4-(L-isoleucyloxy)butyl]guanine,
(R)-9-[2-((13-docosenoyl)-oxymethyl)-4-(L-isoleucyloxy)butyl]guanine,
(R)-2-amino-9-[2-(butyryloxymethyl)-4-(L-isoleucyloxy)butyl]purine,
(R)-2-amino-9-[2-(4-acetylbutyryloxymethyl)-4-(L-isoleucyloxy)butyl]purine,
(R)-2-amino-9-[2-(hexanoyloxymethyl)-4-(L-isoleucyloxy)butyl]purine,
(R)-2-amino-9-[4-(L-isoleucyloxy)-2-(octanoyloxymethyl)butyl]purine,
(R)-2-amino-9-[4-(L-isoleucyloxy)-2-(decanoyloxymethyl)butyl]purine,
(R)-2-amino-9-[4-(L-isoleucyloxy)-2-(dodecanoyloxymethyl)butyl]purine,
(R)-2-amino-9-[4-(L-isoleucyloxy)-2-(tetradecanoyloxymethyl)butyl]purine,
(R)-2-amino-9-[4-(L-isoleucyloxy)-2-(hexadecanoyloxymethyl)butyl]purine,
(R)-2-amino-9-[4-(L-isoleucyloxy)-2-(octadecanoyloxymethyl)butyl]purine,
(R)-2-amino-9-[4-(L-isoleucyloxy)-2-(eicosanoyloxymethyl)butyl]purine,
(R)-2-amino-9-[2-(eicosanoyloxymethyl)-4-(L-isoleucyloxy)butyl]purine,
(R)-2-amino-9-[2-(docosanoyloxymethyl)-4-(L-isoleucyloxy)butyl]purine,
(R)-2-amino-9-[4-(L-isoleucyloxy)-2-((9-tetradecenoyl)oxymethyl)butyl]purine,
(R)-2-amino-9-[2-((9-hexadecenoyl)oxymethyl)-4-(L-isoleucyloxy)butyl]purine,
(R)-2-amino-9-[4-(L-isoleucyloxy)-2-((6-octadecenoyl)oxymethyl)butyl]purine,
(R)-2-amino-9-[4-(L-isoleucyloxy)-2-((9-octadecenoyl)oxymethyl)butyl]purine,
(R)-2-amino-9-[2-((11-eicosanoyl)oxymethyl)-4-(L-isoleucyloxy)butyl]purine, or
(R)-2-amino-9-[2-((13-docosenoyl)oxymethyl)-4-(L-isoleucyloxy)butyl]purine,
or a pharmaceutically accepable salt thereof.
Further preferred compounds include:
(R)-9-[2-(butyryloxymethyl)-4-(L-valyloxy)butyl]guanine,
(R)-9-[2-(4-acetylbutyryloxymethyl)-4-(L-valyloxy)butyl]guanine,
(R)-9-[2-(hexanoyloxymethyl)-4-(L-valyloxy)butyl]guanine,
(R)-9-[2-(octanoyloxymethyl)-4-(L-valyloxy)butyl]guanine,
(R)-9-[2-(decanoyloxymethyl)-4-(L-valyloxy)butyl]guanine,
(R)-9-[2-(dodecanoyloxymethyl)-4-(L-valyloxy)butyl]guanine,
(R)-9-[2-(tetradecanoyloxymethyl-4-(L-valyloxy)butyl]guanine,
(R)-9-[2-hexadecanoyloxymethyl)-4-(L-valyloxy)butyl]guanine,
(R)-9-[2-(octadecanoyloxymethyl)-4-(L-valyloxy)butyl]guanine,
(R)-9-[2-(eicosanoyloxymethyl)-4-(L-valyloxy)butyl]guanine,
(R)-9-[2-(eicosanoyloxymethyl)-4-(L-valyloxy)butyl]guanine,
(R)-9-[2-(docosanoyloxymethyl)-4-(L-valyloxy)butyl]guanine,
(R)-9-[2-((9-tetradecenoyl)oxymethyl)-4-(L-valyloxy)butyl]guanine,
(R)-9-[2-((9-hexadecenoyl)oxymethyl)-4-(L-valyloxy)butyl]guanine,
(R)-9-[2-((6-octadecenoyl)oxymethyl)-4-(L-valyloxy)butyl]guanine,
(R)-9-[2-((9-octadecenoyl)oxymethyl)-4-(L-valyloxy)-butyl]guanine,
(R)-9-[2-((11-eicosanoyl)oxymethyl)-4-(L-valyloxy)butyl]guanine,
(R)-9-[2-((13-docosenoyl)oxymethyl)4-(L-valyloxy)butyl]guanine,
(R)-2-amino-9-[2-(butyryloxymethyl)-4-(L-valyloxy)butyl]purine,
(R)-2-amino-9-[2-(4-acetylbutyryloxymethyl)-4-(L-valyloxy)butyl]purine,
(R)-2-amino-9-[2-(hexanoyloxymethyl)-4-(L-valyloxy)butyl]purine,
(R)-2-amino-9-[2-(octanoyloxymethyl)-4-(L-valyloxy)butyl]purine,
(R)-2-amino-9-[2-(decanoyloxymethyl)-4-(L-valyloxy)butyl]purine,
(R)-2-amino-9-[2-(dodecanoyloxymethyl)-4-(L-valyloxy)butyl]purine,
(R)-2-amino-9-[2-(tetradecanoyloxymethyl)-4-(L-valyloxy)butyl]purine,
(R)-2-amino-9-[2-(hexadecanoyloxymethyl)-4-(L-valyloxy)butyl]purine,
(R)-2-amino-9-[2-(octadecanoyloxymethyl)-4-(L-valyloxy)-butyl]purine,
(R)-2-amino-9-[2-(eicosanoyloxymethyl)-4-(L-valyloxy)butyl]purine,
(R)-2-amino-9-[2-(docosanoyloxymethyl)-4-(L-valyloxy)butyl]purine,
(R)-2-amino-9-[2-((9-tetradecenoyl)oxymethyl)-4-(L-valyloxy)butyl]purine,
(R)-2-amino-9-[2-((9-hexadecenoyl)oxymethyl)-4-(L-valyloxy)butyl]purine,
(R)-2-amino-9-[2-((6-octadecenoyl)oxymethyl)-4-(L-valyloxy)butyl]purine,
(R)-2-amino-9-[2-((9-octadecenoyl)oxymethyl)-4-(L-valyloxy)-butyl]purine,
(R)-2-amino-9-[2-((11-eicosenoyl)-oxymethyl)-4-(L-valyloxy)butyl]purine, or
(R)-2-amino-9-[2-((13-docosenoyl)-oxymethyl)-4-(L-valyloxy)butyl]purine;
or a pharmaceutically acceptable salt thereof.
Other preferred compounds of formula I include:
(R)-9-[4-(butyryloxy)-2-(L-valyloxymethyl)butyl]guanine,
(R)-9-[4-(4-acetylbutyryloxy)-2-(L-valyloxymethyl)butyl]guanine,
(R)-9-[4-(hexanoyloxy)-2-(L-valyloxymethyl)butyl]guanine,
(R)-9-[4-(octanoyloxy)-2-(L-valyloxymethyl)butyl]guanine,
(R)-9-[4-(decanoyloxy)-2-(L-valyloxymethyl)butyl]guanine,
(R)-9-[4-(dodecanoyloxy)-2-(L-valyloxymethyl)butyl]guanine,
(R)-9-[4-(tetradecanoyloxy)-2-(L-valyloxymethyl)butyl]guanine,
(R)-9-[4-hexadecanoyloxy)-2-(L-valyloxymethyl)butyl]guanine,
(R)-9-[4-(octadecanoyloxy)-2-(L-valyloxymethyl)butyl]guanine,
(R)-9-[4-(eicosanoyloxy)-2-(L-valyloxymethyl)butyl]guanine,
(R)-9-[4-(docosanoyloxy)-2-(L-valyloxymethyl)butyl]guanine,
(R)-9-[4-((9-tetradecenoyl)oxy)-2-(L-valyloxymethyl)butyl]guanine,
(R)-9-[4-((9-hexadecenoyl)oxy)-2-(L-valyloxymethyl)butyl]guanine,
(R)-9-[4-((6-octadecenoyl)oxy)-2-(L-valyloxymethyl)butyl]guanine,
(R)-9-[4-((9-octadecenoyl)oxy)-2-(L-valyloxymethyl)-butyl]guanine,
(R)-9-[4-((11-eicosenoyl)oxy)-2-(L-valyloxymethyl)butyl]guanine,
(R)-9-[4-((13-docosenoyl)-oxy)-2-(L-valyloxymethyl)butyl]guanine,
(R)-2-amino-9-[4-(butyryloxy)-2-(L-valyloxymethyl)butyl]purine,
(R)-2-amino-9-[4-(4-acetylbutyryloxy)-2-(L-valyloxymethyl)butyl]purine,
(R)-2-amino-9-[4-(hexanoyloxy)-2-(L-valyloxymethyl)butyl]purine,
(R)-2-amino-9-[4-(octanoyloxy)-2-(L-valyloxymethyl)butyl]purine,
(R)-2-amino-9-[4-(decanoyloxy)-2-(L-valyloxymethyl)butyl]purine,
(R)-2-amino-9-[4-(dodecanoyloxy)-2-(L-valyloxymethyl)butyl]purine,
(R)-2-amino-9-[4-(tetradecanoyloxy)-2-(L-valyloxymethyl)butyl]purine,
(R)-2-amino-9-[4-(hexadecanoyloxy)-2-(L-valyloxymethyl)butyl]purine,
(R)-2-amino-9-[4-(octadecanoyloxy)-2-(L-valyloxymethyl)-butyl]purine,
(R)-2-amino-9-[4-(eicosanoyloxy)-2-(L-valyloxymethyl)butyl]purine,
(R)-2-amino-9-[4-(docosanoyloxy)-2-(L-valyloxymethyl)butyl]purine,
(R)-2-amino-9-[4-((9-tetradecenoyl)oxy)-2-(L-valyloxymethyl)butyl]purine,
(R)-2-amino-9-[4-((9-hexadecenoyl)oxy)-2-(L-valyloxymethyl)butyl]purine,
(R)-2-amino-9-[4-((6-octadecenoyl)oxy)-2-(L-valyloxymethyl)butyl]purine,
(R)-2-amino-9-[4-((9-octadecenoyl)oxy)-2-(L-valyloxymethyl)butyl]purine,
(R)-2-amino-9-[4-((11-eicosenoyl)oxy)-2-(L-valyloxymethyl)butyl]purine, or
(R)-2-amino-9-[4-((13-docosenoyl)oxy)-2-(L-valyloxymethyl)butyl]purine,
or a pharmaceutically acceptable salt thereof.
The compounds of formula I can form salts which form an additional aspect of the invention. Appropriate pharmaceutically acceptable salts of the compounds of formula I include salts of organic acids, especially carboxylic acids, including but not limited to acetate, trifluoroacetate, lactate, gluconate, citrate, tartrate, maleate, malate, pantothenate, isethionate, adipate, alginate, aspartate, benzoate, butyrate, digluconate, cyclopentanate, glucoheptanate, glycerophosphate, oxalate, heptanoate, hexanoate, fumarate, nicotinate, palmoate, pectinate, 3-phenylpropionate, picrate, pivalate, proprionate, tartrate, lactobionate, pivolate, camphorate, undecanoate and succinate, organic sulphonic acids such as methanesulphonate, ethanesulphonate, 2-hydroxyethane sulphonate, camphorsulphonate, 2-napthalenesulphonate, benzenesulphonate, p-chlorobenzenesulphonate and p-toluenesulphonate; and inorganic acids such as hydrochloride, hydrobromide, hydroiodide, sulphate, bisulphate, hemisulphate, thiocyanate, persulphate, phosphoric and sulphonic acids. Hydrochloric acid salts are convenient.
The compounds of Formula I may be isolated as the hydrate. The compounds of the invention may be isolated in crystal form, preferably homogenous crystals, and thus an additional aspect of the invention provides the compounds of Formula I in substantially pure crystalline form, comprising >70%, preferably >90% homogeneous crystalline material, for example >95% homogeneous crystalline material.
The compounds of the invention are particularly suited to oral administration, but may also be administered rectally, vaginally, nasally, topically, transdermally or parenterally, for instance intramuscularly, intravenously or epidurally. The compounds may be administered alone, for instance in a capsule, but will generally be administered in conjunction with a pharmaceutically acceptable carrier or diluent. The invention extends to methods for preparing a pharmaceutical composition comprising bringing a compound of Formula I or its pharmaceutically acceptable salt in conjunction or association with a pharmaceutically acceptable carrier or vehicle.
Oral formulations are conveniently prepared in unit dosage form, such as capsules or tablets, employing conventional carriers or binders such as magnesium stearate, chalk, starch, lactose, wax, gum or gelatin. Liposomes or synthetic or natural polymers such as HPMC or PVP may be used to afford a sustained release formulation. Alternatively the formulation may be presented as a nasal or eye drop, syrup, gel or cream comprising a solution, suspension, emulsion, oil-in-water or water-in-oil preparation in conventional vehicles such as water, saline, ethanol, vegetable oil or glycerine, optionally with flavourant and/or preservative and/or emulsifier.
The compounds of the invention may be administered at a daily dose generally in the range 0.1 to 200 mg/kg/day, advantageously, 0.5 to 100 mg/kg/day, more preferably 10 to 50 mg/kg/day, such as 10 to 25 mg/kg/day. A typical dosage rate for a normal adult will be around 50 to 500 mg, for example 300 mg, once or twice per day for herpes infections and 2 to 10 times this dosage for HIV infections.
As is prudent in antiviral therapy, the compounds of the invention can be administered in combination with other antiviral agents, such as acyclovir, valcyclovir, penciclovir, famciclovir, ganciclovir and its prodrugs, cidofovir, foscarnet and the like for herpes indications and AZT, ddl, ddC, d4T, 3TC, foscarnet, ritonavir, indinavir, saquinavir, delaviridine, Vertex VX 478, Agouron AG1343 and the like for retroviral indications.
The compounds of the invention can be prepared de novo or by esterification of the H2G parent compound which is prepared, for example, by the synthesis methodology disclosed in European Patent EP 343 133, which is incorporated herein by reference.
A typical reaction scheme for the preparation of H2G is depicted below:
The condensation in step 1 is typically carried out with a base catalyst such as NaOH or Na 2 CO 3 in a solvent such as DMF. Step 2 involves a reduction which can be performed with LiBH 4 /tetrahydrofuran in a solvent such as t-BuOH. The substitution in step 3 of the chlorine with an amino group can be performed under pressure with ammonia. Step 4 employs adenosine deaminase which can be conveniently immobilized on a solid support. Cooling the reaction mixture allows unreacted isomeric precursor to remain in solution thereby enhancing purity.
Starting materials for compounds of the invention in which R 3 is hydrogen may be prepared as shown in European Patent EP 186 640, the contents of which are incorporated herein by reference. These starting materials may be acylated as described for H2G below, optionally after protecting the purine 2-amino group with a conventional N-protecting group as defined above, especially BOC (t—BuO—CO—), Z (BnO—CO—) or Ph 3 C—.
The compounds of the invention may be prepared from H2G as described below in Schemes A and B.
A. Direct Acylation Method
Scheme A depicts the preparation of compounds in which R 1 is derived from the amino acid and R 2 is derived from the fatty acid, but the converse scheme is applicable to compounds where R 1 is derived from the fatty acid and R 2 is derived from the amino acid ester. In the variant specifically depicted in scheme A above, G is guanine or 6-deoxyguanine, PG is an optional N-protecting group or hydrogen, R 1 * is the valine or isoleucine side chain and R 2 * is the fatty acid chain. H2G is depicted above as a starting material but this of course may be optionally protected at R 3 or the 2 position of the purine with conventional N-protecting groups (not shown). The H2G (derivative) reacts in the first step with an activated R 1 α-amino acid derivative, as further described below, in a solvent such as dimethylformamide or pyridine, to give a monoacylated product. The R 1 α-amino acid may be suitably N-protected with N-BOC or N-CBz or the like. Under controlled conditions, the first acylation can be made to predominantly take place at the side chain 4-hydroxy group on the side chain of H2G. These controlled conditions can be achieved, for example, by manipulating the reagent concentrations or rate of addition, especially of the acylating agent, by lowering the temperature or by the choice of solvent. The reaction can be followed by TLC to monitor the controlled conditions.
After purification, the R 1 monoacylated compounds are further acylated on the side chain 2-CH 2 OH group with the appropriate activated fatty acid derivative to give diacylated products using similar procedures as for the first esterification step. The diester products are subsequently subjected to a conventional deprotection treatment using for example trifluoroacetic acid, HCl(aq)/dioxane or hydrogenation in the presence of catalyst to give the desired compound of Formula I. The compound may be in salt form depending on the deprotection conditions.
The activated R 1 /R 2 acid derivative used in the various acylations may comprise e.g. the acid halide, acid anhydride, activated acid ester or the acid in the presence of coupling reagent, for example dicyclohexylcarbodiimide, where “acid” in each case represents the corresponding R 1 /R 2 amino acid or the R 1 /R 2 fatty acid. Representative activated acid derivatives include the acid chloride, formic and acetic acid derived mixed anhydrides, anhydrides derived from alkoxycarbonyl halides such as isobutyloxycarbonylchloride and the like, N-hydroxysuccinamide derived esters, N-hydroxyphthalimide derived esters, N-hydroxy-5-norbornene-2,3-dicarboxamide derived esters, 2,4,5-trichlorophenol derived esters, sulfonic acid derived anhydrides (for example, p-toluenesulonic acid derived anhydrides and the like) and the like.
B. Via Protection of the Chain 4-hydroxy Group
wherein G, PG, R 1 * and R 2 * are as described for scheme A.
Scheme B has been exemplified with reference to the preparation of a compound where R 1 is derived from an amino acid and R 2 is derived from the fatty acid ester, but a converse scheme will be applicable to compounds where R 2 is derived from the amino acid and R 1 is derived from the fatty acid. This scheme relies on regioselective protection of the H2G side chain 4-hydroxy group with a bulky protecting group. In scheme B above this is depicted as t-butyldiphenylsilyl, but other regioselective protecting groups such as trityl, 9-(9-phenyl)xanthenyl, 1,1-bis(4-methylphenyl)-1′-pyrenylmethyl may also be appropriate. The resulting product is acylated at the side chain 2-hydroxymethyl group using analogous reagents and procedures as described in scheme A above, but wherein the activated acid derivative is the R 2 fatty acid, for example, myristic, stearic, oleic, elaidic acid chloride and the like. The thus monoacylated compounds are subjected to appropriate deprotection treatment to remove the side chain 4-hydroxy protecting group which can be done in a highly selective manner with such reagents, depending on the regioselective protecting group, as HF/pyridine and the like and manipulation of the reaction conditions, viz reagent concentration, speed of addition, temperature and solvent etc, as elaborated above. The then free side chain 4-hydroxy group is acylated with the activated α-amino acid in a similar way as described in scheme A above.
Additional techniques for introducing the amino acid ester of R 1 /R 2 , for instance in schemes A, B, C, D or E herein include the 2-oxa-4-aza-cycloalkane-1,3-dione method described in International patent application No. WO 94/29311.
Additional techniques for introducing the fatty acid ester of R 1 /R 2 , for instance in schemes A, B, C, D or E herein include the enzymatic route described in Preparative Biotransformations 1.11.8 (Ed S M Roberts, J Wiley and Son, NY, 1995) with a lipase such as SP 435 immobilized Candida antarcticus (Novo Nordisk), porcine pancreatic lipase or Candida rugosa lipase. Enzymatic acylation is especially convenient where it is desired to avoid N-protection and deprotection steps on the other acyl group or the purine 2-amine.
An alternative route to compounds of Formula I in which R 3 is hydrogen is to 6-activate the correponding guanine compound of Formula I (wherein the amino acid ester moiety of R 1 /R 2 is optionally protected with conventional N-protecting groups such as BOC) with an activating group such as halo. The thus activated 6-purine is subsequently reduced to purine, for instance with a palladium catalyst and deprotected to the desired 6-deoxy H2G di-ester.
A further aspect of the invention thus provides a method for the preparation of the compounds of formula I comprising
a) optionally N-protecting the purine 2 and/or 6 positions of a compound of formula I wherein R 1 and R 2 are each hydrogen;
b) regioselectively acylating the compound of Formula I at the side chain 4-hydroxy group with either
i) an optionally N-protected valine or isoleucine group,
ii) an optionally substituted, saturated or monounsaturated C 3 -C 21 COOH derivative, or
iii) a regioselective protecting group;
c) acylating at the side chain 2-hydroxymethyl group with
i) an optionally N-protected valine or isoleucine derivative, or
ii) an optionally substituted, saturated or monounsaturated C 3 -C 21 COOH derivative;
d) replacing the regioselective protecting group at R 1 , if present, with
i) an optionally N-protected valine or isoleucine derivative; or
ii) an optionally substituted, saturated or monounsaturated C 3 -C 21 COOH derivative; and
e) deprotecting the resulting compound as necessary.
Schemes A and B above employ selective acylation to stepwise add the amino acid and fatty acid esters. An alternative process for the preparation of the compounds of formula I starts with a diacylated H2G derivative, wherein both the acyl groups are the same, and employs selective removal of one of the acyl groups to obtain a monoacyl intermediate which is then acylated with the second, differing, acyl group in the same manner as Schemes A and B above.
Accordingly a further aspect of the invention provides a method for the preparation of a compound of the formula I, as defined above, which method comprises
A) the monodeacylation of a diacylated compound corresponding to formula I wherein R 1 and R 2 are both a valyl or isoleucyl ester (which is optionally N-protected) or wherein R 1 and R 2 are both —C(═O)C 3 -C 21 saturated or monounsaturated, optionally substituted alkyl; and
B) acylating the thus liberated side chain 4-hydroxy or side chain 2-hydroxymethyl group with the corresponding valyl, isoleucyl or —C(═O)C 3 -C 21 saturated or monounsaturated, optionally substituted alkyl; and
C) deprotecting as necessary.
This alternative process has the advantage that the preparation of the diacylated H2G derivative is facile and requires little or no purification steps. Selective removal of one only of the acyl groups of a diacylated H2G derivative can be achieved by manipulating the reaction conditions, in particular the temperature, rate of reactant addition and choice of base.
Compounds amenable to this alternative synthesis route are thus of the formula:
wherein R 1 and R 2 are valyl or isoleucyl (which are optionally N-protected) or a —C(═O)C 3 -C 21 saturated or monounsaturated, optionally substituted alkyl; and R 3 is OH or H.
For ease of synthesis in this alternative route, it is preferred that R 1 and R 2 are both initially identical and are most preferably the same amino acid ester. Such a di-amino acid ester will generally be N-protected during its preparation and may be used directly in this condition in the selective deacylation step. Alternatively, such an N-protected di-aminoacylated H2G derivative may be deprotected and optionally reprotected, as described below. The unprotected di-aminoacyl H2G derivative thus comprises one of the following compounds:
(R)-9-[2-(L-isoleucyloxymethyl)-4-(L-isoleucyloxy)butyl]guanine,
(R)-9-[2-(L-valyloxymethyl)-4-(L-valyloxy)butyl]guanine,
(R)-2-amino-9-[4-(L-isoleucyloxy)-2-(L-isoleucyloxymethyl)butyl]purine, and
(R)-2-amino-9-[4-(L-valyloxy)-2-(L-valyloxymethyl)butyl]purine.
These unprotected H2G diacylated derivatives can be directly subject to selective deacylation of one of the acyl groups (typically the side chain 4-position acyl) followed by enzymatic acylation of the liberated 4-hydroxy as described above. Alternatively, the unprotected H2G diacylated derivative can be re-protected and then subjected to the selective deacylation, followed in turn by conventional acylation with the fatty acid ester, as described in Schemes A and B. Conveniently, such a reprotection step is done with a different N-protecting group, having properties appropriate to the subsequent acylation. For example, it is convenient to employ a lipophilic N-protecting group, such as Fmoc when preparing a di-amino acid H2G derivative, as the lipophilic nature of the protecting group assists with separation of the acylated products. On the other hand, the lipophilic nature of Fmoc is of less utility when conducting an acylation with a fatty acid, and thus it is convenient to reprotect a diacylated H2G with an alternative N-protecting group such as BOC.
It will also be apparent that the preparation of the compounds of formula I can commence with the novel monoacylated intermediates of step b i), ii) or iii) in the above defined first method aspect of the invention. These compounds are thus of the formula:
wherein one of R 1 and R 2 is
i) —C(O)CH(CH(CH 3 ) 2 )NH 2 or —C(O)CH(CH(CH 3 )CH 2 CH 3 )NH 2 ,
ii) a —C(═O)C 3 -C 21 saturated or monounsaturated, optionally substituted alkyl, or
iii) a regioselective protecting group; the other of R 1 and R 2 is hydrogen; and R 3 is OH or H.
Useful compounds thus include:
(R)-9-[2-hydroxymethyl-4-(t-butyldiphenylsilyl)butyl]guanine,
(R)-9-[2-hydroxymethyl-4-(trityloxy)butyl]guanine,
(R)-9-[2-hydroxymethyl-4-(9-(9-phenyl)xanthenyloxy)butyl]guanine,
(R)-9-[2-hydroxymethyl-4-(1,1-bis(4-methylphenyl)-1′-pyrenylmethyloxy)butyl]guanine,
(R)-9-[2-hydroxymethyl-4-(decanoyloxy)butyl]guanine,
(R)-9-[2-hydroxymethyl)-4-(dodecanoyloxy)butyl]guanine,
(R)-9-[2-hydroxymethyl-4-(tetradecanoyloxy)butyl]guanine,
(R)-9-[2-hydroxymethyl)-4-(hexadecanoyloxy)butyl]guanine,
(R)-9-[2-hydroxymethyl-4-(octadecanoyloxy)butyl]guanine,
(R)-9-[2-hydroxymethyl)-4-(eicosanoyloxy)butyl]guanine,
(R)-9-[2-hydroxymethyl-4-(docosanoyloxy)butyl]guanine,
(R)-9-[4-hydroxy-2-(decanoyloxymethyl)butyl]guanine,
(R)-9-[4-hydroxy-2-(dodecanoyloxymethyl) butyl]guanine,
(R)-9-[4-hydroxy-2-(tetradecanoyloxymethyl)butyl]guanine,
(R)-9-[4-hydroxy-2-(hexadecanoyloxymethyl)butyl]guanine,
(R)-9-[4-hydroxy-2-(octadecanoyloxymethyl)butyl]guanine,
(R)-9-[4-hydroxy-2-(eicosanoyloxymethyl)butyl]guanine,
(R)-9-[4-hydroxy-2-(docosanoyloxymethyl)butyl]guanine,
(R)-9-[2-hydroxymethyl-4-(L-valyloxy)butyl]guanine,
(R)-9-[2-hydroxymethyl)-4-(L-isoleucyloxy)butyl]guanine,
(R)-9-[4-hydroxy-2-(L-isoleucyloxymethyl)butyl]guanine,
(R)-9-[4-hydroxy-2-(L-valyloxymethyl) butyl]guanine.
(R)-2-amino-9-[2-hydroxymethyl-4-(L-valyloxy)butyl]purine,
(R)-2-amino-9-[2-hydroxymethyl)-4-(L-isoleucyloxy)butyl]purine,
(R)-2-amino-9-[4-hydroxy-2-(L-isoleucyloxymethyl)butyl]purine, and
(R)-2-amino-9-[4-hydroxy-2-(L-valyloxymethyl)butyl]purine.
Regioselectively protected, sidechain 4-hydroxy intermediates from step c) of the above described first method aspect of the invention are also novel compounds. Useful compounds thus include:
(R)-9-[2-decanoyloxymethyl-4-(t-butyldiphenylsilyl)butyl]guanine,
(R)-9-[2-dodecanoyloxymethyl-4-(t-butyldiphenylsilyl)butyl]guanine,
(R)-9-[2-tetradecanoyloxymethyl-4-(t-butyldiphenylsilyl)butyl]guanine,
(R)-9-[2-hexadecanoyloxymethyl-4-(t-butyldiphenylchlorosilane)butyl]guanine,
(R)-9-[2-octadecanoyloxymethyl-4-(t-butyldiphenylsilyl)butyl]guanine,
(R)-9-[2-eicosanoyloxymethyl-4-(t-butyldiphenylsilyl)butyl]guanine, and
(R)-9-[2-docosanoyloxymethyl-4-(t-butyldiphenylsilyl)butyl]guanine.
An alternative process for the preparation of compounds of the invention of the formula I wherein R 3 is —OH is shown in Scheme C.
Referring to Scheme C, malonate 1 (R 4 and R 5 are lower alkyl or benzyl or the like) is alkylated by reaction with from about 0.5 to about 2.0 molar equivalents of acetal 2 (R 6 and R 7 are lower alkyl or benzyl and the like or R 6 and R 7 taken together are —CH 2 CH 2 — or —CH 2 CH 2 CH 2 — or —CH 2 CH 2 CH 2 CH 2 — and X 1 is a leaving group (for example, Cl, Br or l, or a sulfonate such as methanesulfonate, triflate, p-toluenesulfonate, benzenesulfonate and the like)) in the presence of from about 0.5 to about 2.0 molar equivalents of a base (for example, potassium t-butoxide or sodium ethoxide or NaH or KH and the like) in an inert solvent (for example, DMF or THF or dioxane or dioxolane or N-methylpyrrolidone and the like) at a temperature of from about −40° C. to about 190° C. to provide alkylated malonate 3. Alkylated malonate 3 can be purified by distillation or by first treating the crude alkylated malonate with dilute aqueous base (for example, 7% aqueous KOH), followed by removal of volatile impurities by distillation.
Reduction of 3 with from about 0.5 to about 4.0 molar equivalents of an ester to alcohol reducing agent (for example, LiBH 4 or Ca(BH 4 ) 2 or NaBH 4 or LiAlH 4 and the like) in an inert solvent (for example, THF or methyl t-butyl ether or t-BuOH and the like) at a temperature of from about −20° C. to about 100° C. provides diol 4. Enzymatic esterification of 4 by reaction with from about 1.0 to about 20.0 molar equivalents of a vinyl ester 5 (R 8 is C 1 -C 21 saturated or monounsaturated, optionally substituted alkyl) in the presence of a lipase (for example, Lipase PS-30 or Lipase PPL or Lipase CCL and the like) or a phospholipase (for example phospholipase D and the like) provides the desired stereoisomer of ester 6. This reaction can be carried out in the absence of solvent or in the presence of an inert solvent (for example, methyl t-butyl ether or toluene or hexane and the like). The reaction is carried out at a temperature of from about −20° C. to about 80° C.
The alcohol substituent of 6 is converted to a leaving group (for example, a halogen or a sulfonate) by reaction with a halogenating agent (for example NBS/P(Ph) 3 or NCS/P(Ph) 3 or POCl 3 or NCS/P(Ph) 3 /Nal in acetone and like) in an inert solvent (for example, methylene chloride or toluene or ethylacetate and the like) or by reaction with from about 0.8 molar equivalents to about 2.0 molar equivalents of a sulfonyl halide (for example, benzenesulfonylchloride, toluenesulfonylchloride or methane sulfonylchloride and the like) in the presence of from about 1.0 to about 4.0 molar equivalents of a base (for example, triethylamine or potassium carbonate or pyridine or dimethylaminopyridine or ethyldiisopropylamine and the like) in an inert solvent (for example methylene chloride or toluene or ethylacetate or pyridine or methyl t-butyl ether and the like) at a temperature of from about −25° C. to about 100° C. to provide ester 7 (X 2 is a halogen or sulfonate leaving group).
Reaction of 7 with from about 0.9 to about 2.0 molar equivalents of 2-amino-6-chloropurine 8 in the presence of from about 1.0 to about 6.0 molar equivalents of a base (for example, potassium carbonate or LiH or NaH or KH or NaOH or KOH or lithium diisopropylamide or LiN(Si(CH 3 ) 3 ) 2 and the like) in an inert solvent (for example, DMF or THF or acetonitrile or N-methylpyrrolidone or ethanol or DMSO and the like) at a temperature of from about −25° C. to about 140° C. provides substituted purine 9.
Alternatively, the base can be a sterically bulky amine base (for example, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,4-diazabicyclo[2.2.2]octane (Dabco), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), tetramethylguanidine, N,N-diisopropylethylamine and the like) or a sterically bulky phosphazine base (for example, tert-butylimino-tri(pyrrolidino)-phosphorane, tert-butylimino-tri(dimethylamino)phosphorane, tert-octylimino-tri(dimethylamino)phosphorane and the like) in an inert solvent (for example, THF or DMF or DMSO and the like).
Alternatively Mitsunobu coupling (for example P(Ph) 3 /diethyl azidocarboxylate) of alcohol 6 with 2-amino-6-chloropurine 8 provides 9.
Reaction of 9 with from about 2.0 to about 20 molar equivalents of an alcohol R 9 OH (R 9 is an alcohol protecting group such as benzyl or diphenylmethyl and the like) in the presence of from about 1.0 to about 6.0 molar equivalents of a base (for example, potassium t-butoxide or potassium carbonate or NaH or KH or lithium diisopropylamide and the like) in an inert solvent (for example, THF or DMF and the like) at a temperature of from about −25° C. to about 150° C. provides alcohol 10.
Removal of the alcohol protecting group R 9 of 10 (for example, by catalytic hydrogenation in an inert solvent such as ethanol or benzyl alcohol or methanol or THF and the like in the presence of an hydrogenation catalyst such as Pd/C or Pd(OH) 2 and the like) provides substituted guanine 11.
Esterification of 11 by reaction with a) from about 0.8 to about 2.0 molar equivalents of R 10 COOH and a coupling agent (for example DCC/DMAP) and the like in an inert solvent (for example THF or DMF and the like) or b) from about 0.8 to about 2.0 molar equivalents of an activated derivative of R 10 COOH (for example, the acid chloride or N-hydroxysuccinimide ester or R 10 C(O)OS(O) 2 R 30 (R 30 is loweralkyl, phenyl or toluyl) or R 10 C(O)OC(O)R 10 or R 10 C(O)OC(O)R 10a (R 10a is loweralkyl and the like) in the presence of from about 0 to about 3.0 molar equivalents of a base (for example, pyridine or dimethylaminopyridine or triethylamine or ethyldiisopropylamine or N-methylmorpholine or DBU or potassium carbonate and the like) in an inert solvent (for example, methylene chloride or THF or pyridine or acetonitrile or DMF and the like) at a temperature of from about −25° C. to about 100° C. provides ester 12. R 10 is C 3 -C 21 saturated or monounsaturated, optionally substituted alkyl.
The acetal substituent of 12 is deprotected and the resulting aldehyde is reduced by first reacting 12 with from about 0.1 to about 10.0 molar equivalents of an acid (for example, triflic acid or HCl or formic acid or acetic acid/formic acid or sulfuric acid and the like) in an inert solvent (for example, THF/H 2 O or methylene chloride/H 2 O or ethylacetate/H 2 O or ethanol/H 2 O or methanol/H 2 O or water and the like) at a temperature of from about −25° C. to about 100° C. To the crude reaction mixture is added from about 0.1 to about 10.0 molar equivalents of a base (for example, sodium bicarbonate or potassium carbonate or triethylamine or pyridine or KOH and the like), (optionally, additional inert solvent (for example, THF and or methylene chloride or ethylacetate or methyl t-butyl ether or isopropoanol and the like) is added) and from about 0.3 to about 5.0 molar equivalents of an aldehyde reducing agent (for example, sodium borohydride or RaNi/H 2 or borane t-butylamine complex and the like) at a temperature of from about −25 ° C. to about 100° C. to provide alcohol 13. The optical purity of compound 13 can be enhanced by reaction with optically active oraganic sulfonic acids such as (S)-(+)-camphorsulfonic acid and the like. A preferred sulfonic acid for this purpose is (S)-(+)-camphorsulfonic acid.
Alternatively, the acetal substituent of 12 can be hydrolyzed by reaction in an inert solvent with an acid resin (for example, Amberlyst 15 resin, Nafion NR50 resin, Dowex 50WX4-200R resin or Amerlite 120 resin and the like) to provide the corresponding aldehyde. The aldehyde can be isolated prior to reduction to the alcohol 13 as described above or the crude aldehyde can be reduced directly in situ.
Reaction of 13 with from about 0.8 to about 3.0 molar equivalents of N-protected amino acid P 1 NHCH(R 11 )COOH or an activated derivative thereof (P 1 is an N-protecting group (for example, benzyloxycarbonyl, t-butyloxycarbonyl, allyloxycarbonyl and the like) and R 11 is isopropyl or isobutyl) in an inert solvent (for example, THF or dioxane or dioxolane or DMF or methylene chloride and the like) at a temperature of from about 25° C. to about 100° C. provides alcohol 14.
N-deprotection of 14 provides the compound of the invention of formula I wherein R 3 is —OH. For example, when the protecting group can be removed by hydrogenation, such as when the protecting group is Cbz, hydrogenation in the presence of Pd/C in ethanol or Pd/BaCO 3 or Pd/BaSO 4 and the like in THF or isopropanol/THF and the like is preferred.
Alternatively, compound 13 can be reacted with the symmetrical anhydride derived from P 1 NHCH(R 11 )COOH (i.e., P 1 NHCH(R 11 )C(O)O—C(O)CH(R 11 )NHP 1 ) to provide 14. The anhydride can be prepared in situ or can be separately prepared prior to reaction with 13.
Alternatively, 11 can be prepared by hydrolysis of the ester of 9 to an alcohol (for example, by reaction with a base such as K 2 CO 3 , Li 2 CO 3 , Na 2 CO 3 , KHCO 3 , LiOH, NaOH or KOH and the like in an inert solvent such as methanol, ethanol, isopropanol, THF, water or mixtures thereof and the like, most prefereably with K 2 CO 3 in MeOH/H 2 O and the like), followed by direct conversion of the chloro group to an —OH (for example, by reaction with an inorganic base such as KOH or NaOH and the like in H 2 O with heating and the like).
In another alternative method, 11 can be prepared directly by hydrolysis of the chloro-ester 9 (for example, by reaction with an inorganic base such as KOH or NaOH and the like in H 2 O with heating and the like).
In another alternative, the ester of 9 can be hydrolyzed by an esterase in water or an aqueous buffer, with or without the presence of an added organic solvent such as an alcohol (for example, ethanol or isopropanol and the like), THF, DMF or DMSO and the like.
In another alternative method, 11 can be prepared from 9 (or from the hydroxy compound resulting from the hydrolysis of the ester in 9) by reaction with an inorganic base (for example, NaOH, LiOH, KOH and the like, preferably, NaOH) and trimethylamine in an aqueous solvent.
In yet another alternative method, 11 can be prepared directly by hydrolysis of the chloro-ester 9 (for example, by reaction with 1-3 equivalents of a base such as sodium methoxide (and the like) in the presence of mercaptoethanol in a mixed solvent of water and methanol or dioxane (and the like) at a temperature of from about 20° C. to about relfux and the like).
In yet another alternative method, prior to conversion of 9 to 10 or 11, the ester of 9 can be hydrolyzed to the alcohol as described above. The alcohol can then be reesterified and purified (for example, from methyl t-butyl ether and the like). This process leads to an increase in the enantiomeric excess (i.e., purity) of the resulting ester 9. Preferably, the alcohol is reesterified to provide the acetate, which is purified from methyl t-butyl ether.
In yet another alternative method, 13 can be prepared by reaction of 9 (wherein R 8 ═R 10 )with formic acid, optionally with heating, followed by reduction of the aldehyde to give 13.
In yet another alternative, 13 can be prepared from 11 without isolation of intermediates and with in situ generation of the esterification agent, thus increasing purity of the resulting product and allowing increased throughput in the process.
Another alternative process for the preparation of compounds of Formula I wherein R 3 is —OH is shown in Scheme D.
Malonate 1 (R 4 and R 5 are lower alkyl or benzyl and the like) is alkylated with from about 0.5 to about 2.0 molar equivalents of ether 15 wherein X 1 is a leaving group (for example Cl, Br or I, or a sulfonate such as methane sulfonate, triflate, p-toluenesulfonate, benzenesulfonate and the like) and R 12 is —CH(Ph) 2 , —C(Ph) 3 or —Si(t-Bu)(Me) 2 and the like (Ph=phenyl) in the presence of from about 0.5 to about 2.0 molar equivalents of a base (for example potassium t-butoxide or sodium ethoxide or NaH or KH and the like) in an inert solvent (for example DMF or THF or dioxane or dioxolane or N-methyl pyrrolidinone and the like) at a temperature of from about −40° C. to about 190° C. to provide alkylated malonate 16.
Reduction of 16 with from about 0.5 to about 4.0 molar equivalents of an ester to alcohol reducing agent (for example LiBH 4 or Ca(BH 4 ) 2 or NaBH 4 or LiAlH 4 and the like) in an inert solvent (for example, THF or methyl t-butyl ether or ethanol or t-butanol and the like) at a temperature of from about −20° C. to about 100° C. provides diol 17. Enzymatic esterification of 17 by reaction with from about 1.0 to about 20.0 molar equivalents of a vinyl ester 5 (R 8 is C 1 -C 21 saturated or monounsaturated, optionally substituted alkyl) in the presence of a lipase (for example, Lipase PS-30 or Lipase PPL or Lipase CCL and the like) or a phospholipase (for example phospholipase D and the like) provides the desired stereoisomer of ester 18. The reaction can be carried out in the absence of solvent or in the presence of an inert solvent (for example methyl t-butyl ether or toluene or hexane or the like). The reaction is carried out at a temperature of from about −20° C. to about 80° C.
The alcohol substituent of 18 is converted to a leaving group (for example a halogen or sulfonate) by reaction with a halogenating agent (for example NBS/P(Ph) 3 or NCS/P(Ph) 3 or POCl 3 or NCS/P(Ph) 3 /Nal in acetone and the like) in an inert solvent (for example methylene chloride or toluene or ethylacetate and the like) or by reaction with from about 0.8 molar equivalents to about 2.0 molar equivalents of a sulfonyl halide (for example benzenesulfonylchloride, toluenesulfonylchloride or methane sulfonylchloride and the like) in the presence of from about 1.0 to about 4.0 molar equivalents of a base (for example triethylamine or potassium carbonate or pyridine and the like) in an inert solvent (for example, methylene chloride or toluene or ethyl acetate or methyl t-butyl ether and the like) at a temperature of from about −25° C. to about 100° C. to provide ester 19 (X 2 is a halogen or sulfonate leaving group).
Reaction of 19 with from about 0.9 to about 2.0 molar equivalents of 2-amino-4-chloropurine 8 in the presence of from about 1.0 to about 6.0 molar equivalents of a base (for example potassium carbonate or LiH or NaH or KH or NaOH or KOH or lithium diisopropylamide or LiN(Si(CH 3 ) 3 ) 2 and the like) in an inert solvent (for example DMF or THF or acetonitrile or N-methylpyrrolidone or ethanol and the like) at a temperature of from about −25° C. to about 140° C. provides substituted purine 20.
Alternatively, Mitsunobu coupling (for example, P(PH) 3 /diethyl azidocarboxylate) of alcohol 18 with 2-amino-4-chloropurine 8 provides 20.
Reaction of 20 with from about 2.0 to about 20.0 molar equivalents of an alcohol R 9 OH (R 9 is an alcohol protecting group such as benzyl or diphenylmethyl and the like) in the presence of from about 1.0 to about 6.0 molar equivalents of a base (for example, potassium t-butoxide or potassium carbonate or NaH or KH or lithium diisopropylamide and the like in an inert solvent (for example, THF or DMF and the like) at a temperature of from about −25° C. to about 150° C. provides alcohol 21.
Removal of the alcohol protecting group R 9 of 21 (for example by catalytic hydrogenation in an inert solvent such as ethanol or benzyl alcohol or methanol or THF and the like in the presence of an hydrogenation catalyst such as Pd/C or Pd(OH) 2 and the like) provides substituted guanine 22, which can be esterified as described in Scheme C (i.e., 11 to 12) to provide 23.
The ether substitutent of 23 is deprotected by reaction with a) a reducing agent (for example, HCO 2 H and Pd/C and the like) wherein R 12 is —CH(Ph) 2 or —C(Ph) 3 , or b) a desilylating agent (for example Bu 4 NF and the like) wherein R 12 is —Si(t-Bu)(Me) 2 and the like to provide 13.
Alcohol 13 can be converted to I as outlined in Scheme C.
Alternatively, 22 can be prepared by hydrolysis of the ester of 20 to an alcohol (for example, by reaction with K 2 CO 3 in MeOH/H 2 O and the like), followed by direct conversion of the chloro group to an —OH (for example, by reaction with KOH in H 2 O with heating and the like).
In another alternative method, 22 can be prepared directly by hydrolysis of the chloro-ester 20 (for example, by reaction with KOH in H 2 O with heating and the like).
In another alternative method, 22 can be prepared from 20 (or from the hydroxy compound resulting from the hydrolysis of the ester in 20) by reaction with an inorganic base (for example, NaOH, LiOH, KOH and the like, preferably, NaOH) and trimethylamine in an aqueous solvent.
In yet another alternative method, 22 can be prepared directly by hydrolysis of the chloro-ester 20 (for example, by reaction with 1-3 equivalents of a base such as sodium methoxide (and the like) in the presence of mercaptoethanol in a mixed solvent of water and methanol or dioxane (and the like) at a temperature of from about 20° C. to about relfux and the like).
In yet another alternative method, 23 can be prepared by reaction of 20 (wherein R 8 ═R 10 ) with formic acid, optionally with heating, followed by reduction of the aldehyde to give 23.
An additional alternative involves enzymatic esterification of alcohol 4 or 17 with the vinyl ester CH 2 ═CH—OC(O)R 10 (i.e., R 8 ═R 10 in Schemes C and D) to directly incorporate into 6 or 18 the desired carboxylic acid ester of the final product I. This allows the elimination of the ester hydrolysis and reesterification involved in going from 9 to 12 or from 20 to 23.
The processes of Schemes C and D are characterized by the fact that each of the hydroxyl groups of the acyclic side chain is differentiated by the use of different hydroxy protecting groups or precursor groups. This allows the selective acylation of each of the hydroxy groups with either an amino acid or a fatty acid group.
Schemes C and D have been illustrated and described with reference to embodiments of the invention wherein R 1 is derived from an amino acid and R 2 is derived from a fatty acid. However, it will be apparent that respective converse schemes will apply to compounds where R 1 is derived from a fatty acid and R 2 is derived from an amino acid.
Yet another method for preparing compounds of Formula I is shown in Scheme E. Enzymatic esterification of 4 (see Scheme C) by reaction with from about 1.0 to about 20.0 molar equivalents of a vinyl ester 24 (R 10 is C 3 -C 21 saturated or monounsaturated, optionally substituted alkyl) in the presence of a lipase (for example, Lipase PS-30 or Lipase PPL or Lipase CCL and the like) or a phospholipase (for example phospholipase D and the like) provides the desired stereoisomer of ester 25. This reaction can be carried out in the absence of solvent or in the presence of an inert solvent (for example, methyl t-butyl ether or toluene or hexane and the like). The reaction is carried out at a temperature of from about −20° C. to about 80° C.
The alcohol substituent of 25 is converted to a leaving group (for example, a halogen or a sulfonate) by reaction with a halogenating agent (for example NBS/P(Ph) 3 or NCS/P(Ph) 3 or POCl 3 or NCS/P(Ph) 3 /Nal in acetone and like) in an inert solvent (for example, methylene chloride or toluene or ethylacetate and the like) or by reaction with from about 0.8 molar equivalents to about 2.0 molar equivalents of a sulfonyl halide (for example, benzenesulfonylchloride, toluenesulfonylchloride or methane sulfonylchloride and the like) in the presence of from about 1.0 to about 4.0 molar equivalents of a base (for example, triethylamine or potassium carbonate or pyridine or dimethylaminopyridine or ethyldiisopropylamine and the like) in an inert solvent (for example methylene chloride or toluene or ethylacetate or pyridine or methyl t-butyl ether and the like) at a temperature of from about −25° C. to about 100° C. to provide ester 26 (X 2 is a halogen or sulfonate leaving group).
The acetal substituent of 26 is hydrolyzed to the aldehyde 27 by reacting 26 with an acid (for example, trifluoroacetic acid, triflic acid or HCl or formic acid or acetic acid/formic acid or sulfuric acid and the like) in an inert solvent (for example, THF/H 2 O or methylene chloride/H 2 O or ethylacetate/H 2 O or ethanol/H 2 O or methanol/H 2 O or water and the like) at a temperature of from about −25° C. to about 100° C.
To the aldehyde 27 in an inert solvent (for example, THF and or methylene chloride or ethylacetate or methyl t-butyl ether or isopropoanol and the like) is added an aldehyde to alcohol reducing agent (for example, sodium borohydride or RaNi/H 2 or borane t-butylamine complex and the like) at a temperature of from about −25° C. to about 100° C. to provide the corresponding alcohol.
Reaction of the resulting alcohol with from about 0.8 to about 3.0 molar equivalents of N-protected amino acid P 1 NHCH(R 11 )COOH or an activated derivative thereof (P 1 is an N-protecting group (for example, benzyloxycarbonyl, t-butyloxycarbonyl, allyloxycarbonyl, trichloroethylcarbonyl and the like) and R 11 is isopropyl or isobutyl) in an inert solvent (for example, THF or dioxane or dioxolane or DMF or methylene chloride and the like) at a temperature of from about 25° C. to about 100° C. provides diester 28.
Alternatively the alcohol can be reacted with the symmetrical anhydride derived from P 1 NHCH(R 11 )COOH (i.e., P 1 NHCH(R 11 )C(O)O—C(O)CH(R 11 )NHP 1 ) to provide 28.
Conversion of 27 to 28 can be accomplished with or without isolation/purification of the intermediate alcohol. A preferred aldehyde to alcohol reducing agent is borane t-butylamine complex. A preferred esterification agent is the symmetrical anhydride.
Reaction of 28 with purine 29 in the presence of a base (for example potassium carbonate or LiH or NaH or KH or NaOH or KOH or lithium diisopropylamide or LiN(Si(CH 3 ) 3 ) 2 and the like) in an inert solvent (for example, DMF and the like) provides 30. Purine 29 is prepared from 6-chloro-2-amino purine by reaction with R 9 OH in an inert solvent (for example, toluene or THF and the like) in the presence of a base (for example, NaH or KH or NaOH or KOH or potassium t-butoxide and the like). A preferred process for the the preparation of purine 29 involves reaction of 2-amino-6-chloropurine with neat R 9 -OH in the presence of a base such as NaOH or KOH or potassium t-butoxide and the like. Substituted purine 30 is deprotected to provide the compound of Formula I.
Alternatively, in the reaction of 28 with 29, the base can be a sterically bulky amine base (for example, 1,8-diazabicyclo[5.4.0]-undec-7-ene (DBU), 1,4-diazabicyclo[2.2.2]octane (Dabco), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), tetramethylguanidine, N,N-diisopropylethylamine and the like) or a sterically bulky phosphazine base (for example, tert-butylimino-tri(pyrrolidino)-phosphorane, tert-butylimino-tri(dimethylamino)phosphorane, tert-octylimino-tri(dimethylamino)phosphorane and the like) in an inert solvent (for example, THF or DMF or DMSO and the like).
Yet another method for preparing compounds of Formula I is shown in Scheme F. Reaction of 28 with amino-chloropurine 8 in the presence of a base (for example potassium carbonate or LiH or NaH or KH or NaOH or KOH or lithium diisopropylamide or LiN(Si(CH 3 ) 3 ) 2 and the like) in an inert solvent (for example, DMF THF and the like) provides 31. Hydrolysis of 31 to 14 can be accomplished under basic or acidic conditions (for example, with trimethlyamine or DABCO or KOH or LiOH or NaOH and the like in water/THF or methylene chloride and the like or with acetic acid and the like).
Alternatively, 8 can be be alkylated with 28 using a sterically bulky amine base (for example, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,4-diazabicyclo[2.2.2]octane (Dabco), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), tetramethylguanidine, N,N-diisopropylethylamine and the like) or a sterically bulky phosphazine base (for example, tert-butylimino-tri(pyrrolidino)-phosphorane, tert-butylimino-tri(dimethylamino)phosphorane, tert-octylimino-tri(dimethylamino)phosphorane and the like) in an inert solvent (for example, THF or DMF or DMSO and the like).
In each of Schemes C, D and F, the 2-amino-6-chloro-purine (8) can be replaced with 2-amino-6-iodo-purine or 2-amino-6-bromopurine, which can be alkylated and then transformed to the substituted guanine in a manner analogous to that disclosed for alkylation and transformation of 8
Yet another method for preparing the compounds of formula I is shown in Scheme G. Alkylation of 32 with 7 in the presence of a base (for example, potassium carbonate, LiH, NaH and the like) in an inert solvent (for example, DMF THF and the like) provides 33. R 25 is hydrogen or —C(O)NR 27 R 28 wherein R 27 and R 28 are independently selected from loweralkyl, phenyl and benzyl or R 27 and R 28, taken together with the nitrogen to which they are attached, form a pyrrolidinyl group or a piperidinyl group. R 26 is loweralkyl, phenyl or benzyl.
Hydrolysis of 33 to 11 can be accomplished under basic conditions (for example, with KOH in water and the like).
Alternatively, 32 can be alkylated with 7 using a sterically bulky amine base (for example, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,4-diazabicyclo[2.2.2]octane (Dabco), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), tetramethylguanidine, N,N-diisopropylethylamine and the like) or a sterically bulky phosphazine base (for example, tert-butylimino-tri(pyrrolidino)-phosphorane, tert-butylimino-tri(dimethylamino)phosphorane, tert-octylimino-tri(dimethylamino)phosphorane and the like) in an inert solvent (for example, THF or DMF or DMSO and the like).
DETAILED DESCRIPTION OF THE INVENTION
The invention will now be illustrated by way of example only with reference to the following non-limiting Examples, comparative examples and the accompanying Figures, in which:
FIG. 1 depicts plasma H2G levels as a function of time in cynomolgus monkeys administered with a compound of the invention or with an alternative prodrug derivative of H2G, as further explained in Biological Example 3; and
FIG. 2 depicts survival as a function of time for Herpes simplex infected mice administered with various doses of a compound of the invention or a prior art antiviral, as further explained in Biological Example 4.
EXAMPLE 1
(R)-9-[2-(Stearoyloxymethyl)-4-(L-valyloxy)butyl]guanine
This example illustrates the application of preparation scheme A.
a) (R)-9-[4-(N-tert-Butoxycarbonyl-L-valyloxy)-2-(hydroxymethyl) butyl]guanine.
H2G (5 g, 19.7 mmol) was dissolved in DMF (300 ml) under heating and was cooled to room temperature before addition of N-t-Boc-L-valine (5.58 g, 25.7 mmol), DMAP (0.314 g, 2.57 mmol) and DCC (6.52 g, 31.6 mmol). The mixture was stirred at room temperature for 24 h and was then filtered. The product was chromatographed on silica gel and eluted with CH 2 Cl 2 /MeOH to give 2.4 g of the desired intermediate product.
1 H-NMR (250 MHz, DMSO-d 6 ): δ 0.95 (d, 6H), 1.47 (s, 9H), 1.5-1.8 (m, 2H), 1.96-2.20 (m, 2H), 3.40 (m, 2H), 3.91 (t, 1H), 4.05 (m, 2H), 4.21 (t, 2H), 4.89 (t, 1H), 6.6 (br s, 2H), 7.27 (d, 1H), 7.75 (s, 1H), 10.7 (br s, 1H).
b) (R)-9-[4-(N-tert-Butoxycarbonyl-L-valyloxy)-2-(stearoyloxymethyl) butyl]guanine.
The product from step a) (185 mg, 0.41 mmol) was dissolved in pyridine (5 ml), the solution was cooled in an ice bath and stearoyl chloride (179 μl, 0.531 mmol) was added. The solution was kept in the ice bath for 2 h, then at room temperature for 1 h. It was then evaporated and chromatographed on silica gel. It was eluted with dichloromethane/methanol to give 143 mg of the desired intermediate product.
c) (R)-9-[2-(Stearoyloxymethyl)-4-(L-valyloxy)butyl]guanine.
The product from step b) (138 mg, 0.192 mmol) was cooled in an ice bath and trifluoroacetic acid (5 ml) was added. The solution was kept in the ice bath for 45 minutes and was then evaporated to give an oil. Water (0.5 to 1 ml) was added and evaporated twice. The residue was once more dissolved in water (5 ml), filtered and freeze-dried to give 148 mg of the desired product as the bistrifluoracetate salt.
1 H NMR (250 MHz, DMSO-d 6 ): δ 0.97 (t, 3H), 1.05 (dd, 6H), 1.34 (br s, 28 H), 1.59 (m, 2H), 1.80 (m, 2H), 2.25 (m, 1H), 2.36 (t, 2H), 2.50 (m, 1H), 3.98-4.18 (m, 5H), 4.35 (t, 2H), 6.6 (br s, 2H), 8.0 (br s, 1H), 8.4 (br s, 3H), 10.9 (br s, 1H).
EXAMPLE 2
(R)-9-[2-(Myristoyloxymethyl)-4-(L-valyloxy)butyl]guanine
The titled compound was obtained as the bistrifluoracetate salt in a manner analogous to Example 1 using myristoyl chloride instead of stearoyl chloride in step b).
1 H NMR (250 MHz, DMSO-d 6 ): δ 0.97 (t, 3H), 1.05 (dd, 6H), 1.34 (br s, 20H), 1.57 (m, 2H), 1.78 (m, 2H), 2.24 (m, 1H), 2.35 (t, 2H), 2.51 (m, 1H), 3.97-4.20 (m, 5), 4.36 (t, 2H), 6.8 (br s, 1H, 8.5 (br s, 3H), 11.1 (br s, 1H).
EXAMPLE 3
(R)-9-[2-(Oleoyloxymethyl)-4-(L-valyloxy)butyl]guanine
The titled compound was obtained as the bistrifluoroacetyl salt in a manner analogous to Example 1 using oleoyl chloride instead of stearoyl chloride in step b).
1 H NMR (250 MHz, DMSO-d 6 ): δ 0.96 (t, 3H), 1.05 (dd, 6H), 1.35 (br s, 20H), 1.59 (m, 2H), 1.76 (m, 2H), 2.09 (m, 4H), 2.24 (m, 1H), 2.35 (t, 2H), 2.50 (m, 1H), 3.97-4.17 (m, 5H), 4.35 (t, 2H), 5.43 (t, 2H), 6.7 (br s, 2H), 8.0 (br s, 1H), 8.5 (br s, 3H), 11.1 (br s, 1H).
EXAMPLE 4
(R)-9-[2-(Butyryloxymethyl)-4-(L-valyloxy)butyl]guanine
a) (R)-9-[4-(N-tert-Butoxycarbonyl-L-valyloxy)-2-(butyryloxymethyl) butyl]guanine.
DCC (110 mg, 0.53 mmol) was dissolved in dichloromethane (10 ml) and butyric acid (82 mg, 0.93 mmol) was added. After 4 hours at room temperature the mixture was filtered and the filtrate was evaporated. The residue was dissolved in pyridine (5 ml) and (R)-9-[4-(N-tert-Butoxycarbonyl-L-valyloxy)-2-hydroxymethylbutyl]guanine (200 mg, 0.44 mmol) (Example 1, step a) was added. The mixture was stirred for 120 hours at room temperature. According to TLC the reaction was incomplete and more anhydride was made using the procedure above. This anhydride was added and the mixture was stirred for an additional 20 hours. The reaction mixture was evaporated and chromatographed first on silica gel and then on aluminium oxide, in both cases eluted with dichloromethane/methanol to give 79 mg of the intermediate product.
b) (R)-9-[2-(Butyryloxymethyl)-4-(L-valyloxy)butyl]guanine.
The intermediate product of step a was deprotected in a manner analogous to Example 1, step c to give 84 mg of the desired product as the bistrifluoracetate salt.
1 H NMR (250 MHz, D 2 O): δ 0.88 (t, 3H), 1.06 (dd, 6H), 1.53 (m, 2H), 1.93 (q, 2H), 2.25 (t, 2H), 2.36 (m, 1H), 2.60 (m, 1H), 4.06 (d, 1H), 4.14-4.30 (m, 2H), 4.43 (m, 4H), 8.99 (br s, 1H).
EXAMPLE 5
(R)-9-[2-(Decanoyloxymethyl)-4-(L-valyloxy)butyl]guanine
The titled compound was obtained as the bistrifluoroacetate salt in a manner analogous to Example 1 using decanoyl chloride instead of stearoyl chloride in step b.
1 H NMR (250 MHz, D 2 O): (0.90 (m, 3H), 1.01 (d, 6H), 1.28 (br s, 12H), 1.5 (m, 2H), 1.8 (m, 2H), 2.3 (m, 3H), 2.5 (m, 1H), 4.0-4.4 (m, 7H), 8.1 (br s, 1H).
EXAMPLE 6
(R)-9-[2-Docosanoyloxymethyl-4-(L-valyloxy)butyl]guanine
The titled compound was obtained as the bistrifluoroacetate salt in a manner analogous to Example 1 but using in step b the DMAP/DCC conditions of Example 1, step a) in conjunction with docosanoic acid in place of the stearoyl chloride and a mixture of DMF and dichloromethane as solvent.
1 H NMR (250 MHz, DMSO-d 6 ): δ 0.97 (t, 3H), 1.05 (dd, 6H), 1.34 (br s, 36 H), 1.58 (m, 2H), 1.77 (m, 2H), 2.24 (m, 1H), 2.35 (t, 2H), 2.50 (m, 1H), 3.97-4.17 (m, 5H), 4.35 (t, 2H), 6.7 (br s, 2H), 8.1 (br s, 1H), 8.4 (br s, 3H), 11.0 (br s, 1H).
EXAMPLE 7
R-9-(4-(L-Isoleucyloxy)-2-(stearoyloxymethyl)butyl(guanine
This example illustrates the application of preparative scheme B.
a) (R)-9-[2-hydroxymethyl 4-(t-butyldiphenylsilyloxy)butyl]guanine.
H2G (2 g, 8 mmole) was coevaporated with dry DMF two times and was then suspended in dry DMF (120 ml) and pyridine (1 ml). To the suspension was added dropwise t-butyldiphenylchlorosilane (2.1 ml, 8.2 mmole) in dichloromethane (20 ml) at 0 (C over a period of 30 min. The reaction mixture became a clear solution at the completion of the dropwise addition. The reaction continued at 0° C. for two hours and was then kept at 4° C. overnight. Methanol (5 ml) was added to the reaction. After 20 min at room temperature, the reaction mixture was evaporated to a small volume, poured into aqueous sodium hydrogen carbonate solution and extracted with dichloromethane two times. The organic phase was dried over sodium sulphate and evaporated in vacuo. The product was isolated by silica gel column chromatography using a methanol/dichloromethane system with a stepwise increasing MeOH concentration. The product was eluted with 7% MeOH in CH 2 Cl 2 to yield 1.89 g.
b) (R)-9-[2-(Stearoyloxymethyl)-4-(t-butyldiphenylsilyloxy)butyl]guanine.
(R)-9-[2-Hydroxymethyl 4-(t-butyldiphenylsilyloxy)butyl]guanine (2.31 g, 5 mmole) was coevaporated with dry pyridine twice and dissolved in pyridine (20 ml). To the solution was slowly added dropwise stearoyl chloride (1.86 ml, 5.5 mmole, technical grade) in dichloromethane (2 ml) at −5° C. The reaction was kept at the same temperature for 1 hr and then at 5° C. for 2 hr. The reaction was monitored by TLC. Additional stearoyl chloride (0.29 ml) at −5° C. was added due to incompletion of reaction. After 30 min at 5° C., methanol (3 ml) was added and the reaction mixture stirred for 20 min. It was then poured into aqueous sodium hydrogen carbonate solution, and extracted with dichloromethane. The organic phase was dried and the product purified by silica gel column chromatography with stepwise increasing MeOH, eluting with 3.5% MeOH in CH 2 Cl 2 . (Yield 2.7 g).
c) (R)-9-[(4-Hydroxy-2-(stearoyloxymethyl)butyl]guanine.
(R)-9-[2-(Stearoyloxymethyl)-4-(t-butyldiphenylsilyloxy)butyl]guanine (2.7 g, 3.56 mmole) was dissolved in dry THF (30 ml) and hydrogen fluoride-pyridine (1.5 ml) added to the solution. The reaction was kept at 4° C. overnight and monitored by TLC. The reaction reached about 80% conversion. Additional HF-pyridine was added (0.75 ml). After 4 hr, TLC showed that the starting material had disappeared. The reaction mixture was concentrated in vacuo without raising the temperature and more pyridine (5 ml) was added and evaporated again. The product was isolated by silica gel column chromatography. (Yield 1.26 g).
d) (R)-9-[4-(N-BOC-L-isoleucyloxy)-2-(stearoyloxymethyl)butyl]guanine.
(R)-9-(4-Hydroxy-2-(stearoyloxymethyl)butyl(guanine (135 mg, 0.26 mmole) and N-BOC-L-isoleucine (180 mg, 0.78 mmole) were coevaporated with dry DMF twice and dissolved in the same solvent (3.5 ml). To the solution was added 1,3-dicyclohexylcarbodiimide (160 mg, 0.78 mmole) and 4-dimethylaminopyridine (4.8 mg, 0.039 mmole). After reaction for 18 hours, the reaction mixture was filtered through Celite and worked up in a conventional manner. The product was isolated by silica gel column chromatography, eluting at 5% MeOH in CH 2 Cl 2 . (Yield 160 mg)
e) (R)-9-[4-(L-isoleucyloxy)-2-(stearoyloxymethyl)-butyl]guanine.
(R)-9-[4-(N-BOC-L-isoleucyloxy)-2-(stearoyloxymethyl)butyl]guanine (150 mg, 0.205 mmole) from step d) was treated with trifluoroacetic acid (3 ml) at 0° C. for 20 min. The solution was evaporated in vacuo. The residue was coevaporated with toluene twice and kept under vacuum for several hours. The residue was dissolved in MeOH (2 ml) and evaporated to give the trifluoracetate salt as a glass-like product. (Yield 191 mg).
1 H NMR (DMSO-d 6 +D 2 O): δ 8.35 (s, 1H, base), 4.21 (t, 2H, H-4), 4.10 (d, 2H) 3.96 (d, 2H), 3.90 (d, 1H, isoleucine), 2.48 (m, 1H, H-2), 2.15 (2H, stearoyl), 1.85 (m, 1H, isoleucine), 1.68 (m, 2H), 1.48 (m, 4H), 1.68 (m, 28H), 0.81 (m, 9H).
EXAMPLE 8
(R)-9-[2-(Decanoyloxymethyl)-4-(L-isoleucyloxy)butyl]guanine
The title compound was obtained as the bistrifluoroacetate salt in a manner analogous to Example 7 using decanoyl chloride instead of stearoyl chloride in step b).
1 H NMR (DMSO-d 6 ): δ 11.1 (s, 1H, NH), 8.35 (s, br, 3H), 8.28 (s, 1H, base), 6.75 (s, 2H, NH2), 4.23 (t, 2H), 4.07 (d, 2H), 4.05 (m, 3H), 2.4 (m, 1H), 2.21 (t, 2H), 1.83 (m, 1H), 1.66 (m, 2H), 1.45 (m, 2H), 1.39 (m, 2H), 1.22 (s, 12H), 0.84 (m, 9H).
EXAMPLE 9
(R)-9-[4-(L-Isoleucyloxy)-2-(myristoyloxymethyl)butyl]guanine
The title compound was obtained as the bistrifluoroacetyl salt in a manner analogous to Example 1 using N-BOC-L-isoleucine instead of N-BOC-valine in step a) and myristoyl chloride instead of stearoyl chloride in step b).
1 H-NMR (DMSO-d 6 ): δ 10.99 (s, 1H), 8.34 (br s, 3H) 8.15 (s, 1H), 6.67 (br s, 2H), 4.23 (t, 2H), 4.05 (d, 2H), 3.97 (m, 3H), 2.48 (m, 1H), 2.20 (t, 2H), 1.85 (m, 1H), 1.65 (m, 2H), 1.41 (m, 4H), 1.23 (s, 20H), 0.85 (m, 9H).
EXAMPLE 10
(R)-9-[2-(4-Acetylbutyryloxymethyl-4-(L-valyloxy)butyl]guanine
The titled compound was obtained as the bistrifluoroacetate salt in a manner analogous to Example 1 but using in step b) the DCC/DMAP conditions of Example 1, step a) in conjunction with 4-acetylbutyric acid instead of stearoyl chloride.
1 H-NMR (250 MHz, DMSO-d 6 ): δ 1.05 (dd, 6H), 1.77 (m, 4H), 2.19 (s, 3H), 2.24 (m, 1H), 2.36 (t, 2H), 2.44-2.60 (m, 3H), 3.95-4.20 (m, 5H), 4.36 (m, 2H), 6.8 (br s, 2H), 8.3 (br s, 1H), 8.5 (br s, 3H), 11.1 (br s, 1H).
EXAMPLE 11
(R)-9-[2-Dodecanoyloxymethyl-4-(L-valyloxy)butyl]guanine
The titled compound was obtained as the bistriflouroacetate salt in a manner analogous to Example 1 using dodecanoyl chloride instead of stearoyl chloride in step b).
EXAMPLE 12
(R)-9-[2-Palmitoyloxymethyl-4-(L-valyloxy)butyl]guanine
The titled compound was obtained as the bistriflouroacetate salt in a manner analogous to Example 1 using palmitoyl chloride instead of stearoyl chloride in step b).
1 H-NMR (250 MHz, DMSO-d 6 ): δ 0.97 (t, 3H), 1.05 (m, 6H), 1.35 (br s, 24H), 1.58 (m, 2H), 1.78 (m, 2H), 2.25 (m, 1H), 2.35 (t, 2H), 2.51 (m, 1H), 3.97-4.18 (m, 5H), 4.35 (t, 2H), 6.7 (br s, 2H), 8.1 (br s, 1H), 8.5 (br s, 3H), 11.0 (br s, 1H).
EXAMPLE 13
(R)-2-Amino-9-(2-stearoyloxymethyl-4-(L-valyloxy)butyl)purine
This example shows the deoxygenation of group R 1 .
a) (R)-2-Amino-9-(2-stearoyloxymethyl-4-(N-tert-butoxycarbonyl-L-valyloxy)butyl)-6-chloropurine:
To a solution of (R)-9-(2-stearoyloxymethyl-4-(N-tert-butoxycarbonyl-L-valyloxy)butyl)guanine from step b of Example 1 (646 mg, 0.9 mmole) in acetonitrile were added tetramethylammonium chloride (427 mg, 2.7 mmole), N,N-diethylaniline (0.716 ml, 4.5 mmole) and phosphorous oxychloride (0.417 ml, 4.5 mmole). The reaction was kept under reflux and the progression monitored by TLC. After 3 hours the reaction mixture was evaporated in vacuo and the residue was dissolved in dichloromethane, then poured into cold sodium hydrogen carbonate aqueous solution. The organic phase was evaporated and purified by silica gel column chromatography. Yield: 251 mg.
1 H-NMR (CDCl 3 ): δ 7.76 (1H, H-8), 5.43 (br, 2H, NH2), 4.45-4.00 (m, 7H), 2.53 (m, 1H), 2.28 (t 2H), 2.12 (m, 1H), 1.75 (m, 2H), 1.59 (m, 2H), 1.43 (9H), 1.25 (m, 28H), 0.96 (d, 3H), 0.87 (m, 6H).
b) (R)-2-Amino-9-(2-stearoyloxmethyl-4-(N-tert-butoxycarbonyl-L-valyloxy)butyl)purine:
To the solution of (R)-2-amino-9-(2-stearoyloxymethyl-4-(N-tert-butoxycarbonyl-L-valyloxy)butyl)-6-chloropurine (240 mg, 0.33 mmole) in methanol/ethyl acetate (6 ml, 3:1 v/v) were added ammonium formate (105 mg, 1.65 mmole) and 10% palladium on carbon (15 mg). The reaction was kept under reflux for 1 hour and recharged with ammonium formate (70 mg). After one hour more the TLC showed completion of the reaction and the mixture was filtered through Celite and washed extensively with ethanol. The filtrate was evaporated and purified by silica gel column. Yield: 193 mg.
1 H-NMR (CDCl 3 ): δ 8.69 (s, 1H, H-6), 7.74 (s, 1H, H-8), 5.18 (br, s, 2H, NH2), 4.45-4.01 (m, 7H), 2.55 (m, 1H), 2.28 (t, 2H), 2.10 (m, 1H), 1.75 (m, 2H), 1.60 (m, 2H), 1.43 (s, 9H), 1.25 (s, 28H), 0.96 (d, 3H), 0.87 (m, 6H).
c) (R)-2-Amino-9-(2-stearoyloxymethyl-4-(L-valyloxy)butyl)purine:
(R)-2-Amino-9-(2-Stearoyloxmethyl-4-(N-tert-butoxycarbonyl-L-valyloxy)butyl)purine (180 mg, 0.26 mmole) was treated with trifluoroacetic acid (5 ml) at 0° C. for 40 min. It was then evaporated in vacuo and coevaporated successively with toluene and methanol. The residue was freeze-dried overnight to give 195 mg of the desired product.
1 H-NMR (DMSO-d 6 ): δ 8.78 (s, 1H, H-6), 8.32 (br, 3H), 8.29 (s, 1H, H-8), 4.27 (t, 2H), 4.13 (d, 2H), 3.98 (t, 2H, 2H), 3.89 (m, 1H), 2.47 (m, 1H), 2.18 (m, 3H), 1.43 (m, 2H), 1.23 (28H), 0.93 (m, 6H), 0.85 (t, 3H).
EXAMPLE 14
Alternative preparation of (R)-9-[4-Hydroxy-2-(stearoyloxymethyl)butyl]guanine
a) Preparation of ethyl 4,4-diethoxy-2-ethoxycarbonyl-butyrate
Potassium tert-butoxide (141.8 g, 1.11 equiv.) was dissolved in dry DMF (1 L). Diethyl malonate (266 mL, 1.54 equiv.) was added over 5 minutes. Bromoacetaldehyde diethylacetal (172 mL, 1.14 mole) was added over 5 minutes. The mixture was heated to 120° C. (internal temperature), and stirred at 120° C. for 5 hours. The mixture was allowed to cool to room temperature, poured into water (5 L), and extracted with methyl tert-butyl ether (MTBE, 3×600 mL). The organic solution was dried over MgSO 4 , filtered, concentrated, and distilled (0.5 mm, 95-140° C.) to yield the desired diester (244 g, 78%) as a colorless oil.
1 H NMR (CDCl 3 ) δ 1.19 (t, 6H), 1.28 (t, 6H), 2.22 (dd, 2H), 3.49 (m, 2H), 3.51 (t, 1H), 3.65 (m, 2H) 4.20 (qd, 4H), 4.54 (t, 1H).
b) Preparation of 4,4-diethoxy-2-(hydroxymethyl)-butanol
LiBH 4 (purchased solution, 2M in THF, 22.5 mL) and the product of Example 14 step a) (5 g in 15 mL of THF, 18.1 mmol) were combined and warmed to 60° C. and stirred at 60° C. for 4 hours. The reaction mixture was allowed to cool to room temperature and the reaction vessel was placed in a cool water bath. Then triethanolamine (5.97 mL, 1 equiv.) was added at such a rate that the temperature of the reaction mixture was maintained between 20-25° C. Brine (17.5 mL) was added at a rate such that gas evolution was controlled and the mixture was stirred for 45 minutes at room temperature. The layers were separated, the organic layer was washed with brine (2×15 mL). The combined brine washes were extracted with MTBE (methyl tert-butyl ether, 3×20 mL). The combined organic extracts were evaporated and the residue was dissolved in MTBE (50 mL) and washed with brine (25 mL). The brine layer was back-extracted with MTBE (3×25 mL). The combined organic extracts were dried over Na 2 SO 4 , filtered, and concentrated to yield the desired diol (3.36 g, 15.5 mmol, 97%) as a colorless oil.
1 H NMR (CDCl 3 ) δ 1.22 (t, 6H), 1.73 (dd, 2H), 1.92 (m, 1H), 2.67 (bs, 2H), 3.52 (m, 2H), 3.69 (m, 2H), 3.72 (m, 4H), 4.62 (t, 1H).
c) Preparation of (2R)-2-acetoxymethyl-4,4-diethoxy-butanol
Into a 10 ml 1 neck round bottom flask was charged the product of Example 14 step b) (3.84 g, 20 mmol), followed by addition of vinyl acetate (2.6 g, 30 mmol) and finally Lipase PS 30 (69 mg, purchased from Amano, Lombard, Ill.). The mixture was allowed to stir at ambient temperature for 16 hours. Progress of the reaction was closely monitored by TLC (2/1 hexane-EtOAc; stained with Ce 2 (SO 4 ) 3 and charred on hot plate; r.f. of diol is 0.1, monoacetate is 0.3, bis acetate is 0.75). The reaction mixture was diluted with CH 2 Cl 2 and filtered through a 5 micron filter. The filter was washed with additional CH 2 Cl 2 . The filtrate was then concentrated in vacuo to afford the desired product.
d) Preparation of (2S)-2-acetoxymethyl-4,4-diethoxybutyl toluenesulfonate
Into a 100 mL 1-neck round bottom flask, equipped with a magnetic stir bar and septum under N 2 was charged the crude product of Example 14 step c) (4.62 g, 19 mmol), dry CH 2 Cl 2 (20 mL) and Et 3 N (5.62 mL, 40 mmol). To this solution was added tosyl chloride (4.76 g, 25 mmol). The resulting mixture was stirred at ambient temperature for 4 hours. Charged H 2 O (0.27 g, 15 mmol) and stirred vigorously for 4 hours. The reaction mixture was diluted with 80 mL EtOAc and 50 mL H 2 O and the aqueous layer was separated. To the organic layer was added 75 ml of a 5% aq. solution of KH 2 PO 4 . After mixing and separation of the layers, the aqueous layer was removed. The organic layer was washed with 50 mL of saturated NaHCO 3 solution, dried over Na 2 SO 4 , filtered and concentrated in vacuo to a constant weight of 7.40 g of the desired product.
1 H NMR (CDCl 3 ) δ 1.17 (t, 6H); 1.62 (m, 2H); 1.94 (s, 3H); 2.19 (m, 1H); 2.45 (s, 3H); 3.42 (m, 2H); 3.6 (m, 2H); 4.03 (m, 4H); 4.51 (t, 1H); 7.36 (d, 2H); 7.79 (d, 2H).
e) Preparation of
Into a 50 mL 1 neck round bottom flask was charged the product of Example 14 step d) (3.88 g, 10 mmol), anhydrous DMF (20 mL), 2-amino-4-chloro-purine (2.125 g, 12.5 mmol) and K 2 CO 3 (4.83 g). The resulting suspension was stirred at 40° C. under a N 2 blanket for 20 hours. The mixture was concentrated to remove most of the DMF on a rotary evaporator. The residue was diluted with EtOAc (50 mL) and H 2 O (50 mL). The reaction mixture was transferred to a separatory funnel, shaken and the aqueous layer was separated. The aqueous layer was extracted with EtOAc (25 mL). The organic layers were combined and washed with 5% KH 2 PO 4 (75 mL). The organic layer was separated and washed with H 2 O (75 mL), brine (75 mL), dried over Na 2 SO 4 , filtered and concentrated in vacuo to afford 3.95 g of crude product. The crude product was slurried with 40 mL of methyl-t-butyl ether. This mixture was stirred overnight at 4° C. and the mixture was filtered. The filtrate was concentrated to afford 3.35 g of the product as an oil (containing 2.6 g of the desired product based upon HPLC analysis).
300 MHz 1 H NMR (CDCl 3 ) δ 1.19 (m, 6H); 1.69 (2H); 1.79 (s, 1H); 2.03 (s, 3H); 2.52 (m, 1H); 3.48 (m, 2H); 3.62 (m, 2H); 4.04 (m, 2H); 4.16 (m, 2H); 4.61 (t, 1H); 5.12 (bs, 2H); 7.81 (s, 1H).
f) Preparation of
Into a 500 mL 1 neck round bottom flask was charged benzyl alcohol (136 mL), cooled to 0° C., followed by portionwise addition of KO-t-Bu (36 g, 321 mmol). The temperature was allowed to warm to 40° C., and the mixture was stirred 20 minutes. To this mixture was added at 0° C. the crude product of Example 14 step e) (24.7 g, 64.2 mmol) dissolved in 25 mL anhydrous THF and benzyl alcohol (30 mL). The temperature was allowed to slowly warm to 8° C. over 2 hours. The reaction mixture was poured into 500 mL ice and was extracted with 500 mL MTBE. The organic layer was washed with 250 mL of brine, dried over Na 2 SO 4 , filtered and concentrated in vacuo to afford 193 g of a benzyl alcohol solution of the desired product. HPLC analysis indicated that the solution contained 25.96 g of the desired product.
300 MHz 1 H NMR (CDCl 3 ) δ 1.22 (m, 6H); 1.55 (2H); 2.18 (m, 1H); 3.15 (m, 1H); 3.40 (m, 1H); 3.51 (m, 2H); 3.70 (m, 2H); 4.25 (m, 2H); 4.63 (t, 1H); 4.90 (bs, 2H); 5.25 (m, 1H); 5.58 (s, 2H); 7.35 (m, 3H); 7.51 (m, 2H); 7.72 (s, 1H).
MS=(M+H) + =416 (Cl).
g) Preparation of
Into a 100 mL 1 neck round bottom flask was charged the crude product of Example 14 step f) (9.65 g of the benzyl alcohol solution, containing 1.30 g, 3.13 mmol of the product of Example 14, step f) dissolved in absolute EtOH (20 mL). To this was added 0.45 g of 10% Pd/C slurried in 5 mL absolute EtOH. The reaction flask was evacuated and charged with H 2 three times with a balloon of H 2 . The reaction flask was pressurized with 1 atm. H 2 and the reaction mixture was stirred overnight. The reaction mixture was filtered through a pad of diatomaceous earth to remove Pd/C. The volatiles were removed in vacuo. The residue was mixed with 25 mL of isopropyl acetate and then concentrated in vacuo. The residue was diluted with EtOAc (10 mL), seeded with the desired product, heated to reflux and then CH 3 CN (2 mL) and MTBE (35 ml) were added. The mixture was stirred for 30 minutes. The precipitate was filtered and dried to a constant weight of 600 mg of the desired product.
300 MHz 1 H NMR (d 6 -DMSO) δ 1.16 (m, 6H); 1.45 (m, 1H); 1.61 (m, 1H); 2.16 (m, 1H); 3.45 (m, 2H); 3.40 (m, 1H); 3.62 (m, 2H); 4.02 (m, 2H); 4.53 (t, 1H); 4.85 (t, 1H); 6.55 (bs, 1H); 7.75 (s, 1H). MS=(M+H) + =416 (Cl).
h) Preparation of
Into a 25 mL 1 neck round bottom flask was charged the product of Example 14 step g) (0.650 g, 2.0 mmol), pyridine (4 mL) and CH 2 Cl 2 (2 mL), DMAP (10 mg). The mixture was cooled to −5° C. and stearoyl chloride (790 mg, 2.6 mmol) dissolved in CH 2 Cl 2 (0.5 mL) was added over 5 minutes. The resulting mixture was stirred 16 hours at −5° C. Absolute EtOH (0.138 g, 3.0 mmol) was added and the mixture was stirred an additional 1 hour. The reaction mixture was concentrated in vacuo. Toluene (30 mL) was added to the residue and then the mixture was concentrated in vacuo. Again, toluene (30 mL) was added to the residue and then the mixture was concentrated in vacuo. To the residue was added 1% KH 2 PO 4 (25 mL) and this mixture was extracted with CH 2 Cl 2 (60 mL). The organic layer was separated and was dried over Na 2 SO 4 , filtered and concentrated in vacuo to a constant weight of 1.65 g. The crude product was chromatographed on 40 g of SiO 2 , eluting with 95/5 CH 2 Cl 2 -EtOH, affording 367 mg of the desired product.
300 MHz 1 H NMR (CDCl 3 ) δ 0.89 (t, 3H); 1.26 (m, 30 H); 1.65 (m, 3 H); 2.32 (m, 1H); 3.45 (m, 1 H); 3.60 (m, 2H); 4.08 (m, 2H); 4.60 (m, 1 H); 6.0 (bs, 2H); 7.53 (s, 1 H).
i) Preparation of
Into a 25 mL 1 neck round bottom flask was charged the product of Example 14, step h) (0.234 g, 0.394 mmol) dissolved in THF (1.7 mL). To this solution was added triflic acid (0.108 g) in H 2 O 180 mg. The mixture was stirred overnight at room temperature. To the reaction mixture was added saturated NaHCO 3 solution (10 mL), THF (5 mL), CH 2 Cl 2 (2 mL) and NaBH 4 (0.10 g). This mixture was stirred for 30 minutes. To the reaction mixture was added a 5 % solution of KH 2 PO 4 (30 mL). This mixture was extracted with 2×15 ml of CH 2 Cl 2 . The organic layers were combined and dried over Na 2 SO 4 , filtered and concentrated in vacuo to a constant weight of 207 mg. This material was recrystallized from EtOAc (8 mL) and CH 3 CN (0.5 mL) affording 173 mg of the desired product.
300 MHz 1 H NMR (d 6 -DMSO) δ 0.82 (t, 3H); 1.19 (m, 30H); 1.41 (m, 4H); 2.19 (t, 2H); 2.32 (m, 1H); 3.40 (m, 2H); 3.9 (m, 4H); 4.49 (m, 1H); 6.4 (bs, 2H); 7.61 (m, 1.5H); 9.55 (m, 0.5H).
EXAMPLE 15
Alternative preparation of (R)-9-[4-(N-tert-butyloxycarbonyl-L-valyloxy)-2-(stearoyloxymethyl)butyl]guanine
(R)-9-[2-(Stearoyloxymethyl)-4-(t-butyldiphenylsilyloxy)butyl]guanine (45 g) and THF (950 ml) were combined in a 2 L flask. Then Boc-L-valine (3.22 g, 0.25 eq) was added, followed by tetrabutylammonium fluoride (1M in THF, 89.05 mL) over 10 minutes. The clear reaction mixture was stirred at room temperature for 2 hours and 50 minutes with monitoring of the reaction progress by TLC (90/10 CH 2 Cl 2 /MeOH).
To the reaction mixture was added Boc-L-valine (35.43 g, 2.75 eq), DCC (36.67 g, 2.75 eq) and dimethylaminopyridine (1.1 g, 0.15 eq) in THF (25 ml). The reaction mixture was stirred at room temperature for 24 hours. DCU was filtered off and washed with CH 2 Cl 2 . The filtrate was concentrated, and the residue was taken up in 2 liters of CH 2 Cl 2 and washed with 2 L of ½ saturated sodium bicarbonate and brine solutions. On drying and evaporation, approximately 100 g of crude product was obtained. The material was purified by silica chromatography (6000 ml of silica) using 3% MeOH/CH 2 Cl 2 to 5% MeOH/CH 2 Cl 2 to obtain 38.22 mg of the desired product.
EXAMPLE 16
Alternative preparation of (R)-9-[2-(stearoyloxymethyl)-4-(L-valyloxy) butyl]guanine
a) (R)-9-[2-Hydroxymethyl)-4-(t-butyldiphenylsilyloxymethyl)butyl]guanine.
H2G (450.0 g, 1.78 mol) and N,N dimethylformamide (6.4 kg) were charged into a Bucchi evaporator and the mixture warmed to dissolve the solid. The solution was concentrated to dryness under vauum at no more than 90° C. The resulting powder was transferred to a 22 liter flask with stirrer, addition funnel and and temperature probe. N,N-dimethylformamide (1.7 kg) was added followed by pyridine (3.53 kg). The resulting suspension was cooled to −10° C. under nitrogen and stirred at −5°±5° C. as t-butylchlorodiphenylsilane (684 g, 2.49 mol) was added dropwise. The resulting mixture was stirred at −5°±5° C. until the reaction was complete (as monitored by TLC (10:1 methylene chloride/methanol) and HPLC (4.6×250 mm Zorbax RxC8 (5 micron); 60:40 acetonitrile-aq. NH 4 OAC (0.05 M) at 1.5 ml/min; UV detection at 254 nm)). Water (16 kg) was added and the mixture was stirred for 30 minutes to precipitate the product, then the mixture was cooled to 0° C. for 30 minutes. The solid was isolated by filtration and the product cake was washed with cold water and sucked dry with air to provide the crude product as an off-white solid. The crude solid was taken up in pydridine (3 kg) and concentrated under vacuum at 60° C. to remove water. The dry solid residue was slurried with methanol (10 kg) at 60° C. for 1-2 hours and filtered while hot. The filtrate was concentrated under vacuum and the solid residue was refluxed with isopropyl acetate (7 kg) for 30 minutes. The mixture was cooled to 20° C. and filtered. The filter cake was dried under vacuum at 50° C. to provide the title compound as a white solid (555 g).
b) (R)-9-[2-(Stearoyloxymethyl)-4-(t-butyldiphenylsilyloxy)butyl]guanine.
The product of Example 16, step a) (555 g, 1.113 mol) was charged to a 50 liter Buchi evaporator. Pyridine (2.7 kg) was added dropwise to dissolve the solid and the mixture was distilled to dryness under vacuum at 60° C. The residue was taken up in fresh pyridine (2.7 kg) and transferred to a 22 liter flask with stirrer, addition funnel and temperature probe. The solution was cooled to −5° C. under nitrogen. A solution of stearoyl chloride (440 g, 1.45 mol) in methylene chloride (1.5 kg) was added so as to maintain a temperature below 0° C. 4-(N,N-dimethylamino)pyridine (15 g, 0.12 mol) was added and the mixture was stirred at −5-0° C. for 2-4 hours until conversion was complete (as monitored by TLC (10:1 methylene chloride/methanol) and HPLC (4.6×250 mm Zorbax RxC8 (5 micron); 60:40 acetonitrile-aq. NH 4 OAc (0.05 M) at 1.5 ml/min; UV detection at 254 nm)). At the end of the reaction, acetonitrile (8.7 kg) was added and the mixture was stirred for not less than 15 minutes to precipitate the product. The slurry was cooled to 0° C. for 2 hours and the solid isolated by filtration and the filter cake washed with acetonitrile (2 kg). The desired product was obtained as a white solid (775 g).
c) (R)-9-[4-Hydroxy-2-(stearoyloxymethyl)butyl]guanine.
A solution of the product of Example 16, step b) (765 g, 0.29 mol) in tetrahydrofuran (10 kg) was prepared in a reactor. A solution of tetra(n-butyl)ammonium fluoride in tetrahydrofuran (1.7 kg of 1 M solution, 1.7 mol) was added and the resulting clear solution was stirred at 20°±5° C. for 4 hours. Water (32 kg) was added and the resulting slurry was stirred for 1 hour and then cooled to 0° C. for 30 minutes. The precipitate was isolated by filtration and the filter cake was washed successively with water (10 kg) and acetonitrile (5 kg). After drying under vacuum at 25° C., 702 g of crude product was obtained. The crude product was dissolved in refluxing THF (4.2 kg) and water (160 g), then cooled to 40° C. and treated with methylene chloride (14.5 kg). The mixture was allowed to cool to 25°±5° C. for 1 hour, then it was cooled to 5°±5° C. for 1 hour to complete precipitation. The slightly off-white powder was isolated by filtration and dried under vacuum at 40° C. to yield the desired product (416 g).
d) (R)-9-[4-(N-Cbz-L-valyloxy)-2-(stearoyloxymethyl)butyl]guanine.
A solution of N-Cbz-L-valine (169 g, 0.67 mol) in dry THF (750 ml) was prepared in a 2 liter flask with mechanical stirrer, thermometer and addition funnel. A solution of dicyclohexylcarbodiimide (69.3 g, 0.34 mol) in THF (250 ml) was added over 5 minutes and the resulting slurry was stirred at 20°±5° C. for 2 hours. The slurry was filtered and the filter cake was washed with THF (300 ml). The filtrate and wash were charged to a 3 liter flask with stirrer and thermometer. The product of Example 16, step c) (116 g, 0.22 mol) was added as a solid, with a rinse of THF (250 ml). 4-(N,N-dimethylamino)pyridine (2.73 g, 0.022 mol) was added and the white slurry stirred at 20°±5° C. Within 15 minutes, the solids were all dissolved and the reaction was complete within 1 hour (as determined by HPLC: 4.6×250 mm Zorbax RxC8 column; 85:15 acetonitrile—0.2% aq. HClO 4 at 1 ml/min.; UV detection at 254 nm; starting material elutes at 4.1 min. and product elutes at 5.9 min.). The reaction was quenched by addition of water (5 ml) and the solution was concentrated under vacuum to leave a light yellow semisolid. This was taken up in methanol (1.5 liters) and warmed to reflux for 30 minutes. The solution was cooled to 25° C. and the precipitate was removed by filtration. The filtrate was concentrated under vacuum to leave a viscous, pale yellow oil. Acetonitrile, (1 L) was added and the resulting white suspension was stirred at 20°±5° C. for 90 minutes. The crude solid product was isolated by filtration, washed with acetonitrile (2×100 ml) and air-dried overnight to provide the desired product as a waxy, sticky solid (122 g). This was further purified by crystallization from ethyl acetate (500 ml) and drying under vacuum at 30° C. to provide the desired product as a white, waxy solid (104 g).
e) (R)-9-[4-(L-valyloxy)-2-(stearoyloxymethyl)butyl]guanine.
A solution of the product of Example 16, step d), (77 g) in warm (40° C.) ethanol (2.3 L) was charged to an hydrogenation reactor with 5% Pd-C (15.4 g). The mixture was agitated at 40° C. under 40 psi hydrogen for 4 hours, evacuated and hydrogenated for an additional 4-10 hours. The catalyst was removed by filtration and the filtrate was concentrated under vacuum to provide a white solid. This was stirred with ethanol (385 ml) at 25° C. for 1 hour, then cooled to 0° C. and filtered. The filter cake was dried with air, then under vacuum at 35° C. to yield the title compound as a white powder (46 g).
EXAMPLE 17
(R)-9-[2-(L-Valyloxymethyl)-4-(stearoyloxy)butyl]guanine
a) (R)-9-[2-Hydroxymethyl-4-(stearoyloxy)butyl]guanine.
H2G (506 mg; 2.0 mmol) was dissolved in dry N,N-dimethylformamide (40 ml) with pyridine (400 mg; 5.06 mmol) and 4-dimethylaminopyridine (60 mg; 0.49 mmol). Stearoyl chloride (1500 mg; 4.95 mmol) was added and the mixture kept overnight at room temperature. Most of the solvent was evaporated in vacuo, the residue stirred with 70 ml ethyl acetate and 70 ml water, and the solid filtered off, washed with ethyl acetate and water and dried to yield 680 mg of crude product. Column chromatography on silica gel (chloroform:methanol 15:1) gave pure title compound as a white solid.
1 H NMR (DMSO-d 6 ) δ 0.86 (t, 3H); 1.25 (s, 28H); 1.51 (qui, 2H); 1.62 (m, 2H); 2.06 (m, 1H); 2.23 (t, 2H); 3.34 (d, 2H); 3.96 (ABX, 2H); 4.07 (dd, 2H); 6.30 (br s, 2H); 7.62 (s, 1H); 10.45 (s, 1H).
13 C NMR (DMSO-d 6 ) δ 13,8 (C18); 22.0 (C17); 24.4 (C3); 27.7 (C3′); 28.4-28.8 (C4-6, C15); 28.9 (C7-14); 31.2 (C16); 33.5 (C2); 38.0 (C2′); 44.0 (C1′); 60.6/61.8 (C4′, C2″); 116.5 (guaC5); 137.7 (guaC7); 151.4 (guaC4); 153.5 (guaC2); 156.7 (guaC6); 172.7 (COO).
b) (R)-9-[2-(N-Boc-L-valyloxymethyl)-4-(stearoyloxy)butyl]guanine.
A mixture of N-Boc-L-valine (528 mg; 2.1 mmol) and N,N′-dicyclohexyl carbodiimide (250 mg; 1.21 mmol) in dichloromethane (20 ml) was stirred over night at room temperature, dicyclohexylurea filtered off and extracted with a small volume of dichloromethane, and the filtrate evaporated in vacuo to a small volume. (R)-9-[2-Hydroxymethyl-4-(stearoyloxy)butyl]guanine (340 mg; 0.654 mmol), 4-dimethylaminopyridine (25 mg; 0.205 mmol), and dry N,N-dimethylformamide (15 ml) were added and the mixture was stirred for 4 h at 50° C. under N 2 . The solvent was evaporated in vacuo to a small volume. Column chromatography on silica gel, then on aluminum oxide (ethyl acetate:methanol:water 15:2:1 as eluent) gave 185 mg (39%) pure title compound as a white solid.
1 H NMR (CHCl 3 ) δ 0.85-1.0 (m, 9H) 18-CH 3 , CH(CH 3 ) 2 ; 1.25 (s, 28H) 4-17-CH 2 ; 1.44 (s, 9H) t-Bu; 1.60 (qui, 2H) 3-CH 2 ; 1.74 (qua, 2H) 3′-CH 2 ; 2.14 (m, 1H) 2′-CH; 2.29 (t, 2H) 2-CH 2 ; 2.41 (m,1H) CH(CH 3 ) 2 ; 4.1-4.3 (m, 6H) C1′-CH 2 , C2″-CH 2 , C4-CH 2 ; 5.4 (d, 1H) αCH; 6.6 (br s, 2H) guaNH 2 ; 7.73 (s, 1H) guaH8; 12.4 (br s).
13 C NMR (CHCl 3 ) δ 13,9 (C18); 17,5/18.9 (2 Val CH 3 ); 22.4 (C17); 24.7 (C3); 28.1 (C3′); 28.9-29.3 (C4-6, C15); 29.4 (C7-14); 30.7 (Val βC); 31.7 (C16); 34.0 (C2); 35.9 (C2′); 43.9 (C1′); 58.7 (Val αC); 61.4/63.6 (C4′, C2″); 79.9 (CMe 3 ); 116.4 (guaC5); 137.9 (guaC7); 151.7 (guaC4); 153.7 (guaC2); 155.7 (CONH); 158.8 (guaC6); 172.1 (CHCOO); 173.5 (CH 2 COO).
c) (R)-9-[2-(L-Valyloxymethyl)-4-(stearoyloxy)butyl]guanine.
Chilled trifluoroacetic acid (2.0 g) was added to (R)-9-[2-(N-Boc-L-valyloxymethyl)-4-(stearoyloxy)butyl]guanine (180 mg; 0.25 mmol) and the solution kept at room temperature for 1 h, evaporated to a small volume, and lyophilized repeatedly with dioxane until a white amorphous powder was obtained. The yield of title compound, obtained as the trifluoracetate salt, was quantitative.
1 H NMR (DMSO-d 6 ) δ 0.87 (t, 3H) 18-CH 3 , 0.98 (dd, 6H) CH(CH 3 ) 2 ; 1.25 (s, 28H) 4-17-CH2; 1.50 (qui, 2H) 3-CH 2 ; 1.68 (qua, 2H) 3′-CH 2 ; 2.19 (m, 1H) 2′-CH; 2.26 (t, 2H) 2-CH 2 ; 2.40 (m, 1H) CH(CH 3 ) 2 ; 3.9-4.25 (m, 7H) C1′-CH 2 , C2″-CH 2 , C4-CH 2 , αCH; 6.5 (br s, 2H) guaNH 2 ; 7.79 (s, 1H) guaH8; 8.37 (br s, 3H) NH 3 +; 10.73 (br s, 1H) guaNH.
13 C NMR (DMSO-d 6 ) δ 14.2 (C18); 17.9/18.3 (2 Val CH3); 22.3 (C17); 24.6 (C3); 27.7 (C3′); 28.7-29.1 (C4-6, C15); 29.2 (C7-14); 29.5 (Val βC); 31.5 (C16); 33.7 (C2); 35.0 (C2′); 44.1 (C1′); 57.6 (Val αC); 61.6/65.2 (C4′, C2″); 116.1 (guaC5); 116.3 (qua, J 290 Hz, CF3); 137.9 (guaC7); 151.5 (guaC4); 154.0 (guaC2); 156.7 (guaC6); 158.3 (qua, J 15 Hz, CF 3 COO) 169.1 (CHCOO); 173.1 (CH 2 COO).
EXAMPLE 18
Alternative preparation of (R)-9-[2-hydroxymethyl-4-(stearoyloxy)butyl]guanine
H2G (7.60 g, 30 mmol) was heated to solution in dry DMF (200 ml). The solution was filtered to remove solid impurities, cooled to 20° C. (H2G cystallized) and stirred at that temperature during addition of pyridine (9.0 g, 114 mmol), 4-dimethylaminopyridine (0.46 g, 3.75 mmol) and then, slowly, stearoyl chloride (20.0 g, 66 mmol). Stirring was continued at room temperature overnight. Most of the solvent was then evaporated off in vacuo, the residue stirred with 200 ml ethyl acetate and 200 ml water and the solid filtered off, washed with ethyl acetate and water and dried to yield crude product. As an alternative to recrystallization, the crude product was briefly heated to almost boiling with 100 ml of ethyl acetate: methanol: water (15:2:1) and the suspension slowly cooled to 30° C. and filtered to leave most of the 2″ isomer in solution (the 2″ isomer would crystallize at lower temperature). The extraction procedure was repeated once more to yield, after drying in vacuo, 6.57 g (42%) of almost isomer free product.
EXAMPLE 19
Preparation of crystalline (R)-9-[2-stearoyloxymethyl)-4-(L-valyloxy)butyl]guanine
The product of Example 16, step c) (20.07 g, 32.5 mmol) was dissolved in absolute ethanol (400 ml) with heating, filtered, and further diluted with ethanol (117.5 ml). To this solution was added water (HPLC grade, 103.5 ml), and the mixture was allowed to cool to 35-40° C. After the mixture was cooled, water (HPLC grade, 931.5 ml) was added at a constant rate over 16 hours with efficient stirring. After all the water was added, stirring was continued for 4 hours at room temperature. The resulting precipitate was filtered through paper and dried under vacuum at room temperature to obtain the title compound as a white, free flowing crystalline powder (19.43 g, 97%), m pt 169-170° C.
EXAMPLE 20
9-R-(4-Hydroxy-2-(L-valyloxymethyl)butyl)guanine
a) To a solution of 9-R-(4-(tert-butyldiphenylsilyloxy)-2-(hydroxymethyl)butyl)guanine (695 mg, 1.5 mmole) in DMF (30 ml) were added N-Boc-L-Valine (488 mg, 2.25 mmole), 4-dimethylamino pyridine (30 mg, 0.25 mmole) and DCC (556 mg, 2.7 mmole). After 16 hr, the reaction was recharged with N-Boc-L-valine (244 mg) and DCC (278 mg), and was kept for an additional 5 hours. The reaction mixture was filtered through Celite and poured into sodium hydrogen carbonate aqueous solution, and then it was extracted with dichloromethane. The organic phase was evaporated and purified by silica gel column chromatography, giving 950 mg of the N-protected monoamino acyl intermediate.
b) The above intermediate (520 mg, 0.78 mmole) was dissolved in THF (15 ml). To the solution was added hydrogen fluoride in pyridine (70%/30%, 0.34 ml). After two days, the solution was evaporated and coevaporated with toluene. Purification by silica gel column chromatography gave 311 mg of the protected monoamino acyl compound.
1 H-NMR (DMSO-d 6 ): δ 10.41 (s, 1H), 7.59 (1H), 6.26 (br s, 2H), 4.32 (t, 1H), 3.95 (m, 5H), 3.46 (m, 2H), 2.41 (m, 1H), 2.06 (m, 1H), 1.45 (m, 2H), 1.39 (s, 9 H), 0.90 (d, 6H).
c) The product of step b) (95 mg, 0.21 mmole) was treated with a mixture of trifluoroacetic acid (4 ml) and dichloromethane (6 ml) for 1 hr. The solution was evaporated and freeze-dried, to give 125 mg of the unprotected monoaminoacyl product.
1 H-NMR (D 2 O): δ 8.88 (s, 1H), 4.32 (m, 4H), 3.96 (d, 1H), 3.68 (m, 2H), 2.63 (m, 1H), 2.22 (m, 1H), 1.73 (m, 2H), 1.00 (m, 6H).
EXAMPLE 21
(R)-9-(2-Hydroxymethyl-4-(L-isoleucyloxy)butyl)guanine
a) To a solution of (R)-9-(2-hydroxymethyl-4-hydroxybutyl)guanine (2.53 g, 10 mmole) in DMF (250 ml) were added N-Boc-L-isoleucine (2.77 g, 12 mmole), 4-dimethylaminopyridine (61 mg, 0.6 mmole) and DCC (3.7 g, 18 mmole). After reaction for 16 hr at 0° (C, N-Boc-L-isoleucine (1.3 g) and DCC (1.8 g) were recharged, and the reaction was kept overnight at room temperature. The reaction mixture was filtered through Celite and the filtrate was evaporated and purified by silica gel column chromatography, giving 1.25 g of the N-protected monoamino acyl intermediate.
1 H-NMR (DMSO-d 6 ): δ 10.56 (s, 1H), 7.62 (s, 1H), 6.43 (s, 2H), 4.75 (t, 1H), 4.15-3.80 (m, 5H), 3.25 (m, 2H) 2.05 (m, 1H), 1.80-1-05 (m, 14H), 0.88 (m, 6H).
b) The intermediate from step a) (100 mg, 0.21 mmole) was treated with trifluoroacetic acid (3 m) and for 30 min at 0° C. The solution was evaporated and freeaze-dried, to give the titled unprotected mono-aminoacyl product in quantitative yield.
1 H-NMR (DMSO-d 6 +D 2 O): δ 8.72 (s, 1H), 4.15 (m, 4H), 3.90 (d, 1H), 3.42 (m, 2H), 2.09 (m, 1H), 1.83 (m,1H), 1.61 (m, 2H), 1.15 (m, H), 0.77 (d, 3H), 0.71 (t, 3H).
EXAMPLE 22
(R)-9-[2-Hydroxymethyl-4-(L-valyloxy)butyl]guanine
The product of Example 1, step a) was deprotected with trifluoroaacetic acid in the same manner as Example 1, step c).
1 H-NMR (250 MHz, DMSO-d 6 ): δ 1.04 (dd, 6H), 1.55-1.88 (m, 2H), 2.21 (m, 2H), 3.48 (m, 2H), 4.00 (m, 1H), 4.13 (m, 2H), 4.34 (t, 2H), 6.9 (br s, 2H), 8.21 (s, 1H), 8.5 (br s, 3H), 11.1 (br s, 1H).
EXAMPLE 23
(R)-9-[2-(L-Valyloxymethyl)-4-(valyloxy)butyl]guanine
a) (R)-9-[4-(N-Boc-L-valyloxy)-2-(N-Boc-L-valyloxymethyl)butyl]guanine.
Application of the technique described in Example 1, step a), but using 2.7 eqs, 0.28 eqs, and 3.2 eqs of N-Boc-L-valine, DMAP, and DCC, respectively, resulted in the title compound.
1 H NMR (250 MHz, CDCl 3 ) δ 0.95 (m, 12H), 1.42 (br s, 18H), 1.8 (m, 2H), 2.14 (m, 2H), 2.47 (m, 1H), 4.0-4.4 (m, 8H), 6.5 (br s, 2H), 7.67 (s, 1H).
b) (R)-9-[4-(L-Valyloxy)-2-(L-valyloxymethyl)butyl]guanine.
The titled compound was obtained as the tris-trifluoroacetate salt from the intermediate of Example 23 step a) by deprotection in a manner analogous to Example 1 step c).
1 H NMR (250 MHz, D 2 O) δ 1.0 (m, 12H), 1.89 (m, 2H), 2.29 (m, 2H), 2.62 (m, 1H), 4.02 (dd, 2H), 4.38 (m, 6H), 4.89 (br s, ca. 10H), 8.98 (s, 1H).
EXAMPLE 24
(R)-9-[4-hydroxy-2-(stearoyloxymethyl)butyl]gauanine
The titled compound is prepared according to steps a) to c) of Example 7.
1 H NMR (250 MHz, DMSO-d 6 ): δ 10.52 (s, 1H), 7.62 (s, 1H), 6.39 (s, 2H), 4.50 (t, 1H), 3.93 (m, 4H), 3.42 (m, 2H), 2.45 (m, 1H), 2.23 (t, 2H), 1.48 (m, 4H), 1.22 (s, 28H), 0.89 (t, 3H)
EXAMPLE 25
(R)-9-[2-Hydroxymethyl-4-(stearoyloxy)butyl]guanine.
The titled compound is prepared by the procedure of Example 17, step a).
1 H NMR (DMSO-d 6 ) δ 0.86 (t, 3H); 1.25 (s, 28H); 1.51 (qui, 2H); 1.62 (m, 2H); 2.06 (m, 1H); 2.23 (t, 2H); 3.34 (d, 2H); 3.96 (ABX, 2H); 4.07 (dd, 2H); 6.30 (br s, 2H); 7.62 (s, 1H); 10.45 (s, 1H).
EXAMPLE 26
Alternative preparation of (R)-9-[2-stearoyloxymethyl)-4-(L-valyloxy)butyl]guanine
a) (R)-9-[4-N-benzyloxycarbonyl-L-valyloxy)-2-(hydroxymethyl)-butyl]guanine.
Dry H2G (252 mg, 1 mmol), 4-dimethylaminopyridine (122 mg, 1 mmol) and N-Cbz-L-valine p-nitrophenyl ester (408 mg, 1.1 mmol) were dissolved in dry dimethyl formamide (16 ml). After stirring at 23° C. for 30 hours, the organic solvent was removed and the residue carefully chromatographed (silica, 2%-7% methanol/methylene chloride) to afford the desired product as a white solid (151 mg, 31%).
b) (R)-9-[(4-N-benzyloxycarbonyl-L-valyloxy)-2-(stearoyloxymethyl)-butyl]guanine.
A solution of stearoyl chloride (394 mg, 1.3 mmol) in dry methylene chloride (2 ml) was added slowly dropwise under nitrogen to a solution of the product of step a) (243 mg, 1 mmol) and 4-dimethylaminopyridine (20 mg) in dry pyridine (5 ml) at −5° C. The reaction mixture was stirred at that temperature for 12 hours. Methanol (5 ml) was added and the reaction stirred for 1 hour. After removal of the solvent, the residue was triturated with acetonitrile and chromatographed (silica, 0-5% methanol/methylene chloride) to afford the desired product (542 mg, 72%).
c) (R)-9-[2-stearoyloxymethyl)-4-(L-valyloxy)butyl]guanine.
The product of step b) (490 mg, 1 mmol) was dissolved in methanol (30 ml) and 5% Pd/C (100 mg) added. A balloon filled with hydrogen was placed on top of the reaction vessel. After 6 hours at 23° C., TLC showed the absence of starting material. The reaction mixture was filtered through a 0.45 micron nylon membrane to remove the catalyst and the solvent was removed to afford the desired product as a white solid (350 mg, 99%) which was identical (spectral and analytical data) to Example 16.
EXAMPLE 27
Alternative preparation of (R)-9-(4-hydroxy-2-(L-valyloxymethyl)butyl)guanine
(R)-9-(4-(L-valyloxy)-2-(L-valyloxymethyl)butyl)guanine from Example 23 step b) (100 mg, 0,126 mmole) was dissolved in 0.1 N NaOH aqueous solution (6.3 ml, 0.63 mmole) at room temperature. At intervals, an aliquot was taken and neutralized with 0.5 N trifluoroacetic acid. The aliquots were evaporated and analyzed by HPLC to monitor the progress of the reaction. After 4 hours, 0.5 N trifluoroacetic acid solution (1.26 ml, 0.63 mmole) was added to the solution and the reaction mixture was evaporated. The desired product was purified by HPLC, (YMC, 50×4.6 mm, gradient 0.1% TFA+0-50% 0.1% TFA in acetonitrile, in 20 minutes, UV detection at 254 nm. Yield: 13.6%
1 H-NMR (D 2 O): δ 8.81 (s, 1H), 4.36 (m, 4H), 4.01 (d, 1H), 3.74 (m, 2H), 2.64 (m, 1H), 2.25 (m, 1H), 1.73 (m, 2H), 1.03 (dd, 6H).
EXAMPLE 28
Alternative preparation of (R)-9-(2-hydroxymethyl-4-(L-valyloxy)butyl)guanine
HPLC separation of the reaction solution from Example 27 gave the titled compound in 29.2% yield.
1 H-NMR (DMSO-d 6 ): δ 8.38 (s, 3H), 8.26 (s, 1H), 6.83 (br s, 2H), 4.23 (m, 2H), 4.06 (m, 2H), 3.91 (m, 1H), 3.40 (m, 2H), 2.19 (m, 2H), 1.8-1.40 (m, 2H), 0.95 (dd, 6H).
EXAMPLE 29
(R)-9-[(2-stearoyloxymethyl)-4-(L-valyloxy)butyl]guanine monohydrochloride
The product of Example 16, step d) (360 mg, 0.479 mmol) was dissolved in a mixture of methanol (10 ml) and ethyl acetate (10 ml). To the solution was added 10% Pd/C (100 mg) and 1N HCl (520 microliters). The reaction mixture was stirred at room temperature for 2 hours under 1 atm. H 2 . The reaction mixture was filtered and the solvent evaporated from the filtrate to provide the desired product as a crystalline solid (300 mg).
EXAMPLE 30
Alternative preparation of (R)-9-[(2-stearoyloxymethyl)-4-(L-valyloxy)butyl]guanine
a) Preparation of (R)-2-Amino-6-chloro-9-[4,4-diethoxy-2-(hydroxymethyl)butyl]purine.
The product of Example 14, step e) (200 g) was dissolved in methanol (670 mL) and 20% aqueous K 2 CO 3 (43 g K 2 CO 3 in 166 mL H 2 O) was added. The mixture was stirred at 25±5° C. for 30 minutes. The reaction mixture was then cooled to 0-5° C. for about 20 minutes, when a precipitate formed. Water (500 mL) was added and the slurry was mixed at 5±5° C. for 15 minutes. The resulting solid was isolated by filtration and the filter cake was washed with water (100 mL) and dried under vacuum at 20° C. to provide the desired product as a pale yellow powder (81 g). m.p. 156-158° C.
300 MHz 1 H NMR (DMSO-d 6 ) δ 1.04 (m, 6H); 1.36 (m, 1H); 1.55 (m, 1H); 2.10 (m, 1H); 3.40 (m, 6H); 4.06 (m, 2H); 4.48 (t, 1H); 4.78 (t, 1H); 6.93, (br s, 2H); 8.10 (s, 1H).
b) Preparation of (R)-9-[4,4-diethoxy-2-(hydroxymethyl)butyl]guanine.
To the product of Example 30, step a) (22.5 kg, 65.4 moles) was added an aqueous solution of KOH (prepared by dissolving 12.9 kg of KOH in 225 kg of water). This mixture was refluxed for 16 hours. The reaction was cooled to about room temperature and filtered into a larger reactor equipped with a pH electrode standardized to pH 7-10. The filtered solution was cooled to 5° C. and the product precipitated by slow addition of dilute acetic acid solution (prepared by mixing glacial acetic acid (12.6 kg, 210 moles) with 75 kg of water and cooling the mixture to 5° C.) until the pH is between 7.5 and 9.0 (target 8.5). The resulting slurry was immediately filtered and the filter cake was recharged back to the reactor. The reactor was charged with 225 kg of distilled water. The mixture was heated to not more than 50° C. for 30 minutes, then cooled to 15±10° C. and stirred for 30 minutes. The resulting precipitate was filtered by vacuum filtration, rinsed with 50 kg of distilled water and dried in a vacuum oven at not more than 45° C. for not less than 8 hours to provide the desired product as a tan solid.
c) Preparation of Stearoyl-pivaloyl mixed anhydride.
To 22.4 kg of stearic acid (78.7 moles) in 156.4 kg of toluene was added 8.2 kg of triethylamine (81.0 moles). The internal temperature of the resulting slurry was lowered to −5° C., then 9.52 kg of pivaloyl chloride (79.0 moles) was slowly added maintaining an internal temperature of not more than 5° C. The slurry was stirred for 2 hours at 5° C., then warmed to 20° C. and stirred for 4 hours. The triethylammonium hydrochloride precipitate was filtered and washed with 36.6 kg, 35.5 kg and 37.9 kg of toluene. The filtrate was concentrated at not more than 60° C. internal temperature and 61.1 kg of heptane was added, followed by cooling the slurry to −15 to −10° C. After 4 hours of stirring, the resulting solid was collected by vacuum filtration, blown dry for 1 hour with nitrogen and dried in a vacuum oven at room temperature for 1.5 hours to provide the desired product as white crystals (18.9 kg). A further 2.7 kg of the desired product was obtained by concentrating the mother liquors under vacuum and adding 41.1 kg of heptane. The resulting slurry was cooled to −15 to −10° C. for 4 hours, filtered, blown dry with nitrogen for 1 hour and the product dried in a vacuum oven at room temperature.
d) Preparation of (R)-9-[4,4-diethoxy-2-(stearoyloxymethyl)butyl]guanine.
The product of Example 30, step b) (3.9 kg, 11.9 moles), the product of Example 30, step c) (5.2 kg, 13.6 moles) and 300 g of 4-dimethylaminopyridine (2.4 moles) were combined in 103.3 kg of THF at room temperature. After mixing for 16 hours, water (3 kg) was added. After mixing for 45 minutes, the solution was distilled at not more than 45° C. internal temperature. Ethyl acetate (62.9 kg) was charged and the solution was redistilled at not more than 45° C. internal temperature. Acetone (56 kg) was then added and the slurry heated to reflux (56° C.) for 15 minutes. The resulting clear solution was cooled to room temperature (not more than 15° C./hour). After 4 hours at room temperature, the resulting precipitate was filtered and rinsed with acetone (17 kg).
The mother liquors were concentrated under vacuum at not more than 45° C. Ethyl acetate (260 kg) and water (72.1 kg) were charged. The biphasic mixture was stirred and then allowed to settle. The organic phase was separated and was distilled. Ethyl acetate (200 kg) was added and the solution was redistilled. Acetone (101 kg) was charged, the solution heated to reflux (56° C.) for 15 minutes and then the solution was cooled to room temperature (not more than 15° C./hour) and the precipitate was filtered. The product was washed with acetone (19 kg, 15 kg and 15 kg), blown dry with nitrogen for 1 hour and then dried under vacuum at not more than 40° C. for approximately 6 hours to yield the desired product (3.1 kg).
e) Preparation of (R)-9-[4-hydroxy-2-(stearoyloxymethyl)butyl]guanine.
The product of Example 30, step d) (3.0 kg) was slurried in THF (46 L) at 20° C. A solution of trifluoromethanesulfonic acid (2.25 kg) in 2.25 kg of water (prepared by slowly adding the acid to cold water) was added and the reaction mixture was stirred at 22° C. for 2 hours. The reaction mixture was cooled to 15° C. and quenched with a solution of NaHCO 3 (1.5 kg) in water (5.3 kg). Borane t-butylamine complex (powder, 340 g) was added in four portions and then the reaction temperature was increased to 35° C. and stirred for 12 hours. The reaction mixture was added to a solution of 320 g of concentrated HCl (37% aq.) in 115 kg of tap water at 5° C. This mixture was stirred for 30 minutes and the resulting precipitate was filtered and washed with acetonitrile (15 kg). The solids were reprecipitated once or twice from acetone (35 kg). A final precipitation was accomplished by dissolving the product in THF (24 kg) at 65° C., adding water (1.3 kg), cooling to 30° C. and then adding methylene chloride (105 kg). The resulting slurry was cooled to 10° C. and the precipitate was filtered to provide the desired product.
f) Preparation of (R)-9-[4-(N-benzyloxycarbonyl-L-valyloxy)-2-(stearoyloxymethyl)butyl]guanine.
A solution of dicyclohexylcarbodiimide (1500 g, 7.27 moles) in THF (7 L) was added to a reactor containing a mixture of N-carbobenzyloxy-L-valine (3630 g, 14.5 moles) in THF (20 L). The resulting mixture was stirred at 20±5° C. for 1-2 hours. The product of Example 30, step e) (2500 g, 4.81 moles) and 4-dimethylaminopyridine (59 g, 0.48 moles) were charged to a second reactor. To this second reactor was filtered the THF mixture from the first reactor, followed with a rinse of THF (15 L). The resulting mixture was stirred at 20±5° C. for 1-3 hours. Water (600 mL) was added and the solution was concentrated under vacuum at not more than 45° C. The residual oil was taken up in ethyl acetate (14 L) and filtered. The filtrate was washed successively with 10% aqueous sodium bicarbonate (2×14 L) and 10% brine (14 L). The organic phase was concentrated under vacuum and the residue was dissolved in methanol (10 kg) at 50-60° C. The warm solution was added gradually to a mixture of acetonitrile (30 kg) and water (13 kg) at ambient temperature. The mixture was stirred 1 hour at 15° C., then filtered to isolate the crude product, which was dried at 40° C. under vacuum to provide the desired product as a white solid (3.9 kg).
g) Preparation of (R)-9-[(2-stearoyloxymethyl)-4-(L-valyloxy)butyl]guanine.
A hydrogenation reactor was charged with 10% Pd-C (400 g) and the product of Example 30, step f) (2.4 kg). Absolute ethanol (52 L) was added and the mixture was warmed to 40° C. and hydrogenated at 30-40 psi for 3-5 hours. On completion of the reaction, the catalyst was removed by filtration through diatomaceous earth and the filter cake was rinsed well with ethanol (30 L). The combined filtrates were concentrated under vacuum at not more than 60° C. to leave a white solid residue. This was dissolved in isopropanol (15 L) and isopropyl acetate (60 L) at reflux and then allowed to cool to room temperature over 4 hours. After cooling for 3 hours at 15±10° C., the precipitate was isolated by filtration, washed with isopropyl acetate (6 L) and dried under vacuum at 40° C. to provide the desired product as a white powder (864 g).
EXAMPLE 31
Alternative preparation of (R)-9-[(2-stearoyloxymethyl)-4-(L-valyloxy)butyl]guanine
a) Preparation of (2R)-4,4-Diethoxy-2-stearoyloxymethyl-butanol.
Vinyl stearate (17.76 g. 0.057 moles) was charged to a 100 mL round bottom flask with a magnetic stir bar. The flask was immersed with stirring in a 35° C. oil bath. The product of Example 14, step b) (10.0 g, 0.052 moles) and Lipase Amano PS-30 (0.20 g) were added and stirred for four hours at 35° C. The reaction was diluted with hexane (260 mL) and MTBE (115 mL) and filtered through celite. The filtrate was washed twice with water (100 mL), dried with Na 2 SO 4 , and concentrated to provide the desired product (26.21 g) as a clear oil that forms a wet solid on standing at room temperature.
b) Preparation of (2S)-4,4-Diethoxy-2-stearoyloxymethyl-butyl toluenesulfonate.
The product of Example 31, step a) (26.21 g, 0.057 mol) was dissolved in methylene chloride (75 mL) and charged into a 250 mL 3 necked flask equipped with a magnetic stir bar, condenser, N 2 inlet, and temperature probe. Triethylamine (14.4 g) was added followed by p-toluenesulfonyl chloride (16.3 g). The flask was purged with N 2 and heated to reflux (46° C.). The reaction was stirred at reflux 6 hours. The reaction was cooled to room temperature. Water (10 mL) was added and the reaction was stirred vigorously for 16 hours. The reaction mixture was poured into a 1 L separatory funnel containing ethyl acetate (350 mL) and water (350 mL). The organic layer was separated and washed with 7% (w/w) aq. sodium bicarbonate (100 mL). The organic layer was then washed with 23% (w/w) aq. sodium chloride (100 mL). The organic layer was dried with Na 2 SO 4 and filtered. The solution was concentrated to give the desired product (29.4 g) as an oil that formed a wet solid when cooled to room temperature.
c) Preparation of (3S)-3-stearoyloxymethyl-4-toluenesulfonyloxy-butyraldehyde.
The product of Example 31, step b) (29.38 g, assayed at 23.12 g, 0.037 moles) was dissolved in THF (90 mL) and charged into a 250 mL round bottomed flask equipped with a magnetic stir bar and a temperature probe. Charged water (38 mL) and cooled to 10° C. Trifluoroacetic acid (55 mL) was poured in and the mixture was stirred for 25 minutes. The reaction mixture was poured into a 2 L separatory funnel containing 20% (w/w) K 2 CO 3 solution (690 g), ice (600 g), and ethyl acetate (500 mL). The upper organic layer was separated. The aqueous layer was extracted a second time with ethyl acetate (500 mL). The combined organic extracts were washed with 23% (w/w) NaCl solution. The organic layer was separated, dried with Na 2 SO 4 and filtered. The solution was concentrated to 21.5 g of an oil, dissolved in heptane (150 mL), and stirred slowly (crystals formed after 10 minutes). The slurry was stirred 15 hrs. at ambient temperature, filtered and washed with ambient heptane (20 mL). The desired product was obtained as white crystals which were dried to a constant weight of 12.3 g .
d) Preparation of (2S)-4-N-Carbonylbenzyloxy-L-valinyloxy-2-stearoyloxymethyl-butyl toluenesulfonate.
The product of Example 31, step c) (11.91 g, 0.022 mol) was charged to a 250 mL shaker bottle. THF (120 mL) and RaNi (17.8 g) were added. The reaction was pressurized to 4 atm. with H 2 . The reaction was shaken for 1.5 hours. The reaction was filtered and washed with 20 mL THF. The filtrate is diluted with 100 mL of CH 2 Cl 2 , dried with Na 2 SO 4 , filtered, and washed with 25 ml CH 2 Cl 2 . The filtrate was charged to a 500 mL 3 necked flask equipped with a magnetic stir bar and N 2 inlet. N-Cbz-L-valine (13.88 g, 0.055 moles), 1,3-dicyclohexylcarbodiimide (11.37 g, 0.055 moles), and 4-dimethylaminopyridine (0.40 g, 0.003 moles) were added and the reaction was stirred for 1 hr. The reaction mixture became heterogeneous after several minutes. The reaction was filtered and washed with CH 2 Cl 2 (50 mL). The filtrate was diluted with ethyl acetate (600 mL) and washed twice with 7% (w/w) NaHCO 3 solution (100 mL). The organic layer was then washed twice with 5% (w/w) KH 2 PO 4 solution (100 mL). The organic layer was washed with 7% (w/w) NaHCO 3 solution (100 mL), then dried with MgSO 4 and filtered. The solution was concentrated to 19.46 g of oily solids. The solid was dissolved in 30 mL of 8:2 hexanes:ethyl acetate and chromatographed in two parts. Each half was chromatographed on a Flash 40M silica gel cartridge (90 g of 32-63 μm, 60 Å silica 4.0 cm×15.0 cm) and eluted with 8:2 hexanes:ethyl acetate at 25 ml/min. 25 ml fractions were collected. Fractions were analyzed by TLC. Fractions 10-22 contained pure product in the first run and fractions 9-26 contained pure product in the second run. The fractions were combined and concentrated to provide the desired product as a clear viscous oil (12.58 g).
e) Preparation of 6-Benzyloxy-2-amino-purine.
60% Sodium hydride in mineral oil (2.36 g, 0.059 moles) was charged to a 500 mL 3-neck flask equipped with magnetic stirring, temperature probe, condenser, and N 2 inlet. Toluene (250 mL) was added. Benzyl alcohol (50 mL) was added dropwise over 30 minutes. After addition of benzyl alcohol, the reaction was stirred 10 minutes. Then 6-chloro-2-aminopurine (5.00 g, 0.029 moles) was added and the reaction mixture was heated to reflux (115 ° C.) for 4.5 hours. The reaction mixture was filtered hot through a coarse glass fritted funnel and 11.65 g of wet off-white solids were obtained. The wet solids were triturated with CH 2 Cl 2 (100 mL) and water (100 mL). After 10 minutes of stirring the solids had dissolved. The aqueous layer was separated and the pH was lowered to 9 over 3 minutes with 6 M HCl. A white solid precipitate formed. The slurry was filtered, washed with water (50 mL), and dried (in vacuo at 50° C.) to a constant weight to provide the desired product as off-white crystals (5.15 g).
f) Preparation of (R)-9-[(2-stearoyloxymethyl)-4-(N-benzyloxycarbonyl-L-valyloxy)butyl]guanine.
The product of Example 31, step e) (2.40 g, 0.0099 moles) was charged to a 100 mL round bottom flask equipped with magnetic stirring and a N 2 inlet. DMF (6 mL) and potassium carbonate (6.27 g) were added. The mixture was stirred at room temperature for 30 minutes. The product of Example 31, step d) (7.02 g, 0.0091 moles) was dissolved in DMF (21 mL) and added to the mixture. The flask was immersed in a 70° C. oil bath and stirred 24 hours. The reaction was cooled to ambient temperature and poured into a 500 mL separatory funnel containing ethyl acetate (135 mL) and 5% (w/w) KH 2 SO 4 solution (135 mL). The top organic layer was kept and washed with 7% (w:w) NaHCO 3 solution (100 mL). The organic layer was dried with MgSO 4 and filtered. The solution was concentrated to 9.79 of oily solids. This was triturated in 50 mL of 1:1 hexanes:ethyl acetate, filtered, and concentrated to 9.10 g of yellow oil. The oil was dissolved in 20 mL of 1/1 hexanes-ethyl acetate and chromatographed on a Flash 40M silica gel cartridge (90 g of 32-63 μm, 60 Å silica, 4.0 cm×15.0 cm) eluted with 6:4 hexanes:ethyl acetate at 25 ml/min. 25 ml fractions were collected. Fractions were analyzed by TLC. Fractions 27-92 contained pure product by TLC. The pure fractions were combined and concentrated to yield the desired product as an oil (2.95 g).
g) Preparation of (R)-9-[(2-stearoyloxymethyl)-4-(L-valyloxy)butyl]guanine.
The product of Example 31, step f) (2.63 g, 0.0031 moles) was dissolved in ethanol (50 mL) and charged into a 500 mL round bottom flask. 10% Pd/C (0.5 g) was slurried in ethanol (20 mL) and added to the flask. The reaction was stirred under H 2 (1 atm from balloon) for 1.5 hours. The slurry was heated briefly to dissolve any solids, filtered through celite, and washed with hot ethanol (50 mL). The filtrate was concentrated to give 1.752 g of white solid. The solid was dissolved in isopropyl alcohol (10 mL) and isopropyl acetate (42 mL) at 70° C. The solution was cooled to 15° C. over 2 hours and stirred at 15° C. for 12 hours. The solution was cooled to 0° C. over 30 minutes and stirred for 1 hour. The slurry was filtered and washed with isopropyl acetate (10 mL). The solid was dried in vacuo at 50° C. to provide the desired product (0.882 g).
The mother liquors were concentrated to give 0.55 g of white solid which was dissolved in isopropyl alcohol (3mL) and isopropyl acetate (16 mL) at 75° C. The solution was cooled to 15° C. for 2 hours, then filtered and dried as above to to provide an additional 0.181 g of the desired product.
EXAMPLE 32
Alternative preparation of Ethyl 4,4-Diethoxy-2-ethoxycarbonyl butyrate
To a suspension of sodium ethoxide (20 g, 0.294 moles) in dimethylformamide (68 g) was added diethyl malonate (49 g, 0.306 moles) during 13 minutes. After the addition was complete, the mixture was heated to 110° C. and bromoacetaldehyde diethyl acetal (40 g, 0.203 moles) was added over 1 hour and 45 minutes. After the addition was complete, the mixture was heated at 110° C. for 7 hours. The reaction mixture was cooled to room temperature and methyl t-butyl ether (160 g) and water (100 g) were added and the mixture was stirred for 15 minutes. The organic layer was separated and treated with 7% aqueous potassium hydroxide solution (155 g). The layers were separated and the organic layer was washed with water (100 g) and then with brine (60 g). The organic layer was concentrated to give the crude desired product. The crude product was heated under house vacuum (approximately 45 mm of Hg) at 160-170° C. (bath temperature) to distill off the volatile impurities, providing 43.6 g of the desired product.
EXAMPLE 33
Alternative preparation of (R)-9-[4,4-diethoxy-2-(hydroxymethyl)butyl]guanine.
To a 100 mL one neck flask was added the product of Example 30a) (5 g, 0.0145 moles), followed by the addition of a solution of KOH (2.05 g, 0.0445 moles) in water (20 mL). The mixture was stirred at reflux for 16-20 hours. Then the reaction mixture (at reflux) was adjusted to pH 7.0 by the addition of acetic acid. The reaction mixture was then cooled to room temperature and stirred for 30 minutes. The resulting precipitate was collected by filtration and washed with water (5 mL). The resulting solid was dried overnight at not more than 50° C. to provide 4.45 g of the desired product.
EXAMPLE 34
Alternative purification of (R)-9-[4-hydroxy)-2-(stearoyloxymethyl)butyl]guanine as the (S)-(+)-camphorsulfonic acid salt
In a 250 mL round bottom flask was placed the product of Example 14i) (13.0 g) and (1S)-(+)-10-camphorsulfonic acid (5.85 g). Heptane (50 mL) was added and the mixture was stirred for 15 minutes. Then tetrahyrofuran (THF; 50 mL) was added and the mixture was stirred for 5 hours. The resulting precipitate was collected by filtration and washed with heptane (100 mL). The resulting solid was dried under vacuum at 45° C. to provide the desired product (11.3 g). HPLC analysis of the product indicated 98.76% e.e.
EXAMPLE 35
Preparation of
A 50 mL round bottom flask was charged with the product of Example 14 h) (1.0 g, 1.7 mmol), THF (20 mL), H 2 O (1 mL), and Amberlyst 15 resin (1.0 g). The solution was then heated to 65° C. for 3 hours. The solution was then filtered hot and the resin was washed with THF (2×10 mL). The solvent was then removed under vacuum to give the desired product (0.74 g, 84%).
EXAMPLE 36
Alternative preparation of (R)-9-[4-hydroxy)-2-(stearoyloxymethyl)butyl]guanine
A 100 mL round bottom flask was charged with the product of Example 14 h) (2.45 g, 4.14 mmol), THF (25 mL), H 2 O (1 mL) and Amberlyst 15 resin (2.5 g). The solution was then heated to 65° C. for 3 hours. The solution was then filtered hot and the resin was washed with THF (2×15 mL). The solution of the crude aldehyde was cooled to room temperature and a solution of borane t-butylamine complex (0.3 g, 3.45 mmol), in THF/H 2 O (1/1 20 mL) was added dropwise to the aldehyde solution. The solution was stirred at room temperature for 1.5 hours, and the reaction was then quenched by addition of H 2 O (100 mL). After stirring at room temperature for an additional 30 min., the precipitate was isolated by filtration and dried to give 1.00 g (47%) of the desired product.
EXAMPLE 37
Alternative preparation of (R)-9-[4-(N-benzyloxycarbonyl-L-valyloxy)-2-(stearoyloxymethyl)butyl]guanine
a) N-Carbobenzyloxy-L-valine Anhydride
A solution of dicyclohexylcarbodiimide (5 kg, 24 moles) in acetonitrile (17.5 kg) was added to a reactor containing a solution of N-carbobenzyloxy-L-valine (12.5 kg, 50 moles) in acetonitrile (200 kg). The mixture was stirred at 5+/−5° C. for 6 hours and the resulting solid was filtered off. The filtrate was concentrated under vacuum at not more then 45° C. and the residue was dissolved in toluene (50 kg) at 40° C. Heptane (50 kg) was added and the mixture was cooled to 15+/−5° C. The precipitate was filtered off and dried to give 10.2 kg of the desired product.
b) (R)-9-[4-(N-benzyloxycarbonyl-L-valyloxy)-2-(stearoyloxymethyl)butyl]-guanine
A mixture of (R)-(-[4-hydroxy-2-(stearoyloxymethyl)butyl]guanine (5.2 kg, 10 moles), N-CBZ-L-valine anhydride (6.3 kg, 13 moles), 4-dimethylaminopyridine (60 g, 0.5 moles) and tetrahydrofuran (67 kg) was stirred for 2-4 hours at 25+/−5° C. Water (2 kg) was added and the mixture was concentrated under vacuum at not more then 45° C. The residue was dissolved in ethyl acetate (58 kg) and extracted with 10% aqueous sodium bicarbonate (2×50 kg) and water (1×50 kg). The ethyl acetate solution was concentrated under vacuum and the residue was dissolved in methanol (20 kg) at 50+/−5° C. The solution was cooled to 20+/−5° C. and diluted with acetonitrile (50 kg) and water (3 kg). The precipitate was filtered off and dried under vacuum to give the desired product (5.3 kg).
EXAMPLE 38
Alternative preparation of (R)-9-[4,4-diethoxy-2-(stearoyloxymethyl)butyl]-guanine
To a stirred solution of stearic acid (1.05 g) and N-mehtylmorpholine (0.62 g) in THF (13 mL) at 0-4° C. was added a solution of p-tosyl chloride (0.67 g) in THF (2 mL) at −3 to −4° C. The mixture was stirred at room temperature for 3 hours. The product of Example 14g) (1.0 g) and 4-dimethylaminopyridine (75 mg) were added and the slurry was stirred at room temperature for 5 days and quenched with 135 mL of water. The mixture was stirred overnight and the precipitate was filtered and washed with water. The wet filter cake was dried under vacuum (40° C.) to give the desired product (1.3 g) as a light yellow powder.
EXAMPLE 39
Alternative preparation of (R)-9-[4,4-diethoxy-2-(hydroxymethyl)butyl]guanine
The product of Example 30a) (10.0 g, 29.1 mmoles) was added to a solution of sodium hydroxide (2.33 g, 5.82 mmoles) in water (200 mL). A solution of trimethylamine (6.61 mL of 40 wt. % solution in water, 43.6 mmoles) was charged to the suspension. The heterogeneous mixture was stirred at room temperature overnight. The reaction was diluted with water (50 mL) and then extracted with ethyl acetate (200 mL). The water layer was charged with a saturated solution of ammonium sulfate (300 mL). The mixture was stirred at room temperature for 30 hours and the resulting precipitate was filtered. The filter cake was washed with ethyl acetate (100 mL). The product was dried in a vacuum oven (high house vacuum, 45° C.) overnight to provide the desired product (7.88 g).
EXAMPLE 40
Alternative preparation of (R)-9-[4,4-diethoxy-2-(hydroxymethyl)-butyl]guanine
A 50 gallon stainless steel reactor was purged with nitrogen and charged with the product of Example 30a) (13.5 kg) and DMAP (0.48 kg). To the solids was added methyl t-butyl ether (108 kg), followed by triethylamine (4.0 kg). Acetic anhydride (4.64 kg) was added last. The resulting mixture was stirred at ambient temperature for 30 minutes. Distilled water (56 kg) was charged to the reactor and the contents were stirred for 30 minutes. After allowing the mixture to settle for 30 minutes, the lower layer was drained and 50 kg of saturated brine was added to the reactor. The contents of the reactor were stirred for 30 minutes and let settle for 30 minutes. The lower layer was drained and a Karl Fischer reading was done on the organic layer to assure that the water content was less than 2.5%. The organic layer was stirred at ambient temperature for 24 hours. The resulting precipitate was filtered off and the filtrate was concentrated under vacuum, followed by a methanol (22 kg) chase. To the resulting residue was added methanol (49 kg) and 10.8 kg of a 50% aqueous KOH solution. The mixture was heated to relux for one hour. The methanol was removed by distillation and the distillation residue was diluted with distilled water (112 kg) and 9.2 kg of a 50% aqueous KOH solution. The resulting mixture was heated to reflux for 16 hours. The contents of the reactor were cooled to 25° C. and were then adjusted to pH 7.0 using 37% aqueous acetic acid solution. The internal temperature of the reactor was then adjusted to 10° C. and the contents stirred for 30 minutes. The resulting slurry was centrifuged and the resulting wet cake was charged back to the reactor. To the cake was charged distilled water (70 kg). The internal temperature was adjusted to 50° C. and the contents were stirred for 30 minutes. Then the internal temperature was adjusted to 20° C. and the contents stirred for 30 minutes. The resulting slurry was centrifuged and the cake rinsed once with distilled water (15 kg). The cake was transferred to dryer trays and dried at 45° C. under vacuum for 18 hours to provide the desired product as a pale yellow powder (8.6 kg, 99% ee).
EXAMPLE 41
Alternative preparation of (R)-9-[4-hydroxy-2-(stearoyloxymethyl)butyl]-guanine
To a 2 liter round bottom, 3-neck flask equipped with a nitrogen inlet, temperature probe, rubber septum and mechanical stirrer was charged stearic acid (25.0 g), THF (525 mL) and triethylamine (12.2 mL). The resulting solution was cooled to ≦0° C. using an ice/salt bath. Pivaloyl chloride (10.3 mL) was added slowly via a syringe, maintaining the reaction temperature at less than 5° C. The resulting slurry was stirred at 0±5° C. for 2 hours. The ice bath was removed and the reaction allowed to warm to room temperature. The resulting precipitate was filtered and the filter cake was rinsed with THF (100 mL). The resulting clear filtrate was added to a 3 liter 3-neck flask (equipped with a nitrogen inlet and mechanical stirrer) charged with the product of Example 40 (22.5 g) and DMAP (1.7 g). The reaction mixture was stirred overnight at room temperature. The reaction mixture was then cooled to 18° C. and a room temperature solution of 1:1 aqueous triflic acid (27.5 g triflic acid) was added slowly, maintaining the temperature at less than 23° C. The resulting solution was stirred at approximately 22 C. for 4.5 hours. Then the reaction mixture was cooled to 18° C. and diulted with water (70 mL). Sodium bicarbonate was added to adjust the pH to 6-7 (target 6.5). The mixture was stirred at room temperature for 30 minutes.
The bath temperature was set at 35° C. and the borane-t-butylamine complex (4.52 g) was added in several portions over 50 minutes. The reaction mixture was stirred at 35° C. overnight. An additional portion of borane-t-butylamine (200 mg) was added and the mixture stirred for an additional 3 hours. The reaction mixture was quenched by pouring it into a cold solution of 5 mL of HCL in 625 mL of water. The resulting pH was 5-6 (target less than pH 6). The resulting mixture was stirred for 3 hours at room temperature and then filtered. The filter cake was dried overnight under house vacuum at 35° C. The filter cake,optionally, can be washed with acetonitrile prior to drying. The dried solid was suspended in acetone (1100 mL) and heated to reflux. The slurry was held at reflux for 30 minutes and then cooled to room temperature. After stirring at room temperature for one hour, the mixture was filtered. The filter cake was air-dried on the filter funnel for 30 minutes and then suspended in THF (350 mL). The THF mixture was heated to reflux and water (35 mL) was added. The flask containing the mixture was removed from the heating bath and allowed to cool. When the temperature reached less than 30° C., ethyl acetate (1050 ml) was added and the mixture was stirred for one hour at room temperature. The resulting slurry was filtered and the filter cake was dried overnight at 35° C. to provide the desired product as a white powder (30.4 g).
EXAMPLE 42
Alternative preparation of (2S)-4-N-Carbonylbenzyloxy-L-valinyloxy-2-stearoyloxymethyl-butyl toluenesulfonate
The product of Example 31c) (6.00 g) was dissolved in THF (60 mL). Borane t-butylamine comlex (0.48 g) was added neat at room temperature. The reaction mixture was stirred at room temperature for 1.25 hours. The pH was adjusted to 7-8 by addition of 5% aqueous HCl. The reaction mixture was diluted with THF (60 mL) and was washed with 20% brine (40 mL) and then again with saturated brine (30 mL). The organic solution was filtered through a pad of silica gel, dried over magnesium sulfate (6.0 g) for one hour and filtered. The filtrate was added to the product of Example 37a) (7.0 g) and DMAP (70 mg). The mixture was stirred under nitrogen at room temperature for about 3 hours. An additional amount of the product of Example 37a) (0.5 g) was added and the mixture was stirred overnight at room temperature. An additional amount of the product of Example 37a) (0.5 g) was added and the mixture was stirred overnight. The reaction mixture was diluted with ethyl acetate (90 mL) and washed with half-saturated sodium bicarbonate (90 mL), with brine (60 mL), with 5% KH 2 PO 4 (60 mL) and brine (60 mL). The organic solution was dried over sodium sulfate and concentrated to provide the desired product as a yellow oil (6.88 g).
EXAMPLE 43
(R)-2-Amino-6-chloro-9-[4-(N-benzyloxycarbonyl-L-valyloxy)-2-(stearoyloxymethyl)butyl]purine
A 100 ml round bottom 3-neck flask was charged with lithium hydride (58 mg, 7.3 mmol) and DMF (10 mL). 2-Amino-6-chloropurine (1.14 g, 6.72 mmol) was added al at once at room temperature. The mixture was stirred at room temperature for 40 minutes under nitrogen. The product of Example 31d) (5.2 g, 6.72 mmol) as a solution in DMF (10 mL) was added dropwise. After complete addition, the reaction mixture was stirred at 40-50° C. under nitrogen for 27 hours. The reaction mixture was cooled to room temperature and poured into a separatory funnel containing ethyl acetate (100 mL) and 5% aqueous KH 2 PO 4 (100 mL). The organic layer was separated and washed with saturated aqueous sodium bicarbonate (50 mL) and brine (50 mL). The organic phase was concentrated under vacuum. The crude product was dissolved in methylene chloride (5 mL) and chromatographed on flash silica gel (10 g) (eluent: 1% methanol/methylene chloride (1000 mL), 5% methanol/methylene chloride(250 mL)) to provide the desired product (3.06 g).
EXAMPLE 44
Alternative preparation of (R)-9-[4-(N-benzyloxycarbonyl-L-valyloxy)-2-(stearoyloxymethyl)butyl]guanine
A 25 mL round bottom flask was charged with the product of Example 43 (0.2 g, 0.26 mol), triethylamine (0.20 mL of 40% aq. solution), THF (4 mL) and water (1 mL). The resulting solution was stirred at room temperature for 20 hours. The solvent was removed under vacuum and the residue was dissolved in ethyl acetate (20 mL). This solution was dried over sodium sulfate and the solvent was evaporated under vacuum. The crude product was chromatographed on flash silica gel (10 g) (eluant: 1/10 methanol/methylene chloride (400 mL)) to give the desired product as a colorless oil (0.15 g).
EXAMPLE 45
Alternative preparation of (R)-9-[4-(N-benzyloxycarbonyl-L-valyloxy)-2-(stearoyloxymethyl)butyl]guanine
The product of Example 43 (145 mg, 0.188 mol) was dissolved in glacial acetic acid (1.9 mL) and the solution was heated to 110° C. for 3 hours. The solution was then cooled to room temperature and the acetic acid was removed by distillation under reduced pressure. The residue was dissolved in ethyl acetate and washed with water, aqueous sodium bicarbonate and bringe. The organic solution was evaporated under reduced pressure to give the desired product (134 mg).
EXAMPLE 46
Alternative preparation of (R)-2-Amino-6-chloro-9-[4,4-diethoxy-2-(hydroxymethyl)butyl]purine
DBU (36.8 g, 0.24 mol) was added to a suspension of 2-amino-6-chloropurine (41 g, 0.24 mol) in DMF (340 mL) at room temperature under nitrogen. After 5 minutes, the product of Example 14d) (85 g, 0.22 mol) was added. The mixture was stirred at 40-45° C. for 15-20 hours. Then the mixture was diluted with methyl t-butyl ether (340 mL), toluene (340 mL), water (340 mL) and brine (340 mL). After mixing for 15 minutes, the organic layer was separated and the aqueous layer was extracted with toluene (2×300 mL). The combined organic layer was washed with water (500 mL) and concentrated under vacuum at 60° C. bath temperature. The resulting oil was diluted with methanol (260 mL) and cooled to 5° C. A solution of K 2 CO 3 (16 g, 0.12 mol) in water (65 mL) was added over 15 minutes maintaining the reaction mixture temperature below 10° C. The mixture was stirred at 10° C. for 1 hour. Then the mixture was diluted with brine (500 mL) and stirred for 30 minutes. The resulting solid was filtered, washed with 5% methanol in water (50 mL) and the filter cake was dried to give the desired product as a white solid (39 g). cl EXAMPLE 47
Alternative preparation of (R)-2-Amino-6-chloro-9-[4,4-diethoxy-2-(acetoxymethyl)butyl]purine
2-Amino-6-chloropurine (0.6 g, 3.6 mmol) and tert-butylimino-tri(pyrrolidino)phosphorane (1.1 g, 3.6 mmol) were mixed in anhydrous THF (4 mL) for 10 minutes at 40° C. The product of Example 14d) (1.16 g, 3.0 mmol) was added and the mixture was stirred at 41-43° C. overnight. The THF was removed by evaporation under vacuum and the residue was diluted with methyl t-butyl ether (10 mL), water (5 mL) and brine (5 mL). The organic layer was separated and the aqueous layer was extracted with toluene (2×10 mL). The combined organic layer was washed withwater (25 mL) and concentrated under vacuum. The residue was slurried with methyl t-butyl ether (12 mL) and water (0.1 mL) and filtered. The filtrate was concentrated under vacuum and slurried with hexane (10 mL) and methyl t-butyl ether (1 mL). The resulting solid was filtered and dried to provide the desired product (0.73 g).
EXAMPLE 48
Alternate preparation of (R)-2-Amino-6-chloro-9-[4-(N-benzyloxycarbonyl-L-valyloxy)-2-(stearoyloxymethyl)butyl]purine
The title compound was prepared following the procedure of Example 47, but substituting the product of Example 31d) for the product of Example 14d).
EXAMPLE 49
Alternate preparation of (R)-2-Amino-6-chloro-9[4-(N-benzyloxycarbonyl-L-valyloxy)-2-(stearoyloxymethyl)butyl]purine
The title compound can be prepared following the procedure of Example 48, but substituting DBU for tert-butylimino-tri(pyrrolidino)-phosphorane.
EXAMPLE 50
2-Amino-6-iodopurine
To a 2 liter single-neck round bottom flask with a mechanical stirrer was charged 2-amino-6-chloropurine (41.0 g, 242 mmol). The flask was cooled in an ice-water bath. The the reaction flask was charged Hl (47% solution, pre-cooled in a refrigerator, 250 mL) in one portion. The resulting suspension was stirred for 16 hours at ice-water bath temperature. Water (500 mL) was charged to the reaction flask. The suspension was stirred at 0° C. for 1 hour. The precipitate was filtered and washed with water (3×250 mL). The filter cake was transferred to a 250 mL filtration flask. 6 M NaOH solution (85 mL) was added to the solid through the filter to rinse out residual solid and wash into the filter flask. The solution obtained was added slowly to a boiling solution of acetic acid (25 mL) and water (250 mL). The resulting suspension was cooled to room temperature and stirred at room temperature for 2 hours. The solid was collected by centrifugation, washed with water (2×250 mL), followed by heptane (250 mL). The solid was first spin-dried on the centrifuge for 30 minutes and then dried in a vacuum oven overnight to provide the desired product (61.3 g).
EXAMPLE 51
Alternative preparation of (R)-9-[4-(N-benzyloxycarbonyl-L-valyloxy)-2-(stearoyloxymethyl)butyl]guanine
a) (R)-2-Amino-6-iodo-9-[4-(N-benzyloxycarbonyl-L-valyloxy)-2-(stearoyloxymethyl)butyl]purine
To a 50 mL single neck round bottom flask was charged the product of Example 31d) (2.0 g, 2.58 mmol), 2-amino-6-iodopurine (0.742 g, 2.84 mmol), DBU (0.425 mL) and DMF (10 mL). The reaction mixture was stirred for 20 hours at 40° C. Ethyl acetate (30 mL) was added to the reaction mixture and stirring continued for 30 minutes. The reaction mixture was filtered and the filtered solid was washed with ethyl acetate (2×30 mL). The filtrate and washings were combined and washed with water (3×25 mL). The organic solution was evaporated under vacuum. The residue was redissolved in ethyl acetate (50 mL) and again evaporated under vacuum to azeotropically remove any residual water, providing the desired product (2.1 g).
1 H NMR (300 MHz, d 6 -DMSO): δ 8.06 (s, 1H), 7.36 (br s, 5H), 6.78 (br s, 2H) 3.85-4.2 (m, 9H), 2.15 (t, 2H), 0.8-1.7 (m, 43H)
Mass Spec. (ESI): 863 (M+H) +
b) Alternative preparation of (R)-2-Amino-6-iodo-9-[4-(N-benzyloxycarbonyl-L-valyloxy)-2-(stearoyloxymethyl)butyl]purine
The desired product was obtained following the procedure of Example 51a) with the replacement of DBU by K 2 CO 3 (1.5 g).
c) (R)-9-[4-(N-benzyloxycarbonyl-L-valyloxy)-2-(stearoyloxymethyl)butyl]guanine
The product of Example 51a) (3.4 g, 3.94 mmol), acetonitrile (45 mL), water (35 mL), acetic acid (45 mL) and sodium acetate (3.05 g) were mixed and heated to reflux (86-87° C.) for 30 hours. The volatile solvent was revoed by evaporation under reduced pressure. The aqueous layer was extracted with ethyl acetate (3×200 mL). The combined extracts were mixed with saturated sodium bicarbonate (2×100 mL) for 30 minutes. The organic layers were separated and washed with saturated sodium bicarbonate (100 mL), followed by water washes (3×100 mL). The organic solvent was evaporated under reduced pressure. To the residue was added anhydrous ethyl acetate (3×200 mL), with evaporation of the solvent each time under reduced pressure, to provide a solid. The solid was recrystallized from refluxing acetonitrile (50 mL). After cooling the acetonitrile mixture to room temperature, it was allowed to stand at room temperature overnight and then was cooled to −13° C. for 30 minutes. The resulting solid was collected by filtration, washed with acetonitrile (2×10 mL) and dired in a vacuum oven to provide the desired product (2.4 g).
EXAMPLE 52
(R)-2-Amino-6-iodo-9-[4,4-diethoxy-2-(acetoxymethyl)butyl]purine
To a 100 mL single neck round bottom flask was charged the product of Example 14d) (9.3 g, 23.9 mmol), 2-amino-6-iodopurine (4.8 g, 18.4 mmol), DBU (3.6 mL, 24.0 mmol) and DMF (50 mL). The mixture was stirred for 16 hours at 45° C. The reaction mixture was cooled to room temperature and ethyl acetate (250 mL) was added and stirring continued for 30 minutes. The reaction mixture was filtered and the filtered solid was washed with ethyl acetate (2×125 mL). The filtrate and washings were combined and washed with water (4×50 mL). The organic solution was evaporated under reduced pressure. Ethyl acetate (50 mL) was added to the residue and evaporated under reduced pressure. Methyl t-butyl ether (300 mL) was added to the residue and stirred. The resulting solid was filtered and dried to provide the desired product (8.8 g). (K 2 CO 3 can be used in place of DBU in the above procedure to provide the desired product).
1 H NMR (300 MHz, CDCl 3 ): δ 7.81 (s, 1H), 5.12 (br s, 2H), 4.61 (t, 1H), 4.16 (m, 1H), 4.04 (m, 2H), 3.62 (m, 2H), 3.48 (m, 2H), 2.52 (m, 1H), 2.03 (s, 3H), 1.79 (s, 1H), 1.69 (m, 2H), 1.19 (m, 6H).
EXAMPLE 53
Alternative preparation of (R)-9-[(2-stearoyloxymethyl)-4-(L-valyloxy)butyl]guanine
a) Preparation of (R)-9-[4-(N-benzyloxycarbonyl-L-valyloxy)-2-(stearoyloxymethyl)butyl]-guanine
To a 500 mL round bottom flask was added the product of Example 30e) (10.4 g, 20.0 mmol), the product of Example 37a) (11.7 g, 24.2 mmol), DMAP (52 mg, 0.43 mmol) and THF (170 mL). The mixture was stirred at room temperature for 4 hours. Water (10 mL) was added and the solvent was evaporated under reduced pressure (bath temperature of approximately 45° C.). Residual THF was chased with ethyl acetate (40 mL). The residue was dissolved in ethyl acetate (200 mL) and the solution was washed with saturated sodium bicarbonate (3×100 mL) and then water (100 mL) and the organic solution was evaporated under reduced pressure (bath temperature of approximately 45° C.). Residual ethyl acetate was chased with isopropanol (25 mL) to provide the desired product in crude form as 14 g of an orange, sticky solid.
b) Preparation of (R)-9-[(2-stearoyloxymethyl)-4-(L-valyloxy)butyl]-guanine
To the flask containing the crude product of Example 53a) was added isopropanol/THF (4/1, 100 mL) and the mixture was heated to 45-50° C. to dissolve the solids. The solution was cooled to room temperature. To a separate 500 mL round bottom flask was added 10% Pd/C (1.00 g) and the flask was evacuated and back-filled with nitrogen three times. Then isopropanol/THF (4/1, 25 mL) was added. The solution of the product of Example 53a) was then added to the catalyst flask, along with two 35 mL isopropanol/THF (4/1) rinses. The reaction flask was then evacuated and back-filled with hydrogen three times. The solution was then heated to 40-45° C. for 16 hours. Then the hydrogen-filled balloon was replaced with a condenser and the reaction mixture was heated to 65° C. for 25 minutes. The reaction mixture was then filtered through celite (6.05 g) and the filter cake was washed with isopropanol/THF (4/1, 2×50 mL). The filtrate was concentrated under vacuum (bath temperature 45° C.) and residual THF was chased with isopropanol (50 mL).
To the flask was added isopropanol (50 mL) and the mixture was heated to about 80° C. to dissolve the solids. Isopropyl acetate (150 mL) was added and heating was continued to dissolve the solid which formed. Once all solids were dissolved, the solution was cooled to room temperature and stirred for 12 hours. The resulting solid was filtered and dried to provide a light gray solid (9.0 g). This solid was added to a 500 mL round bottom flask, along with activated carbon (2.25 g) and isopropanol (200 mL). The mixture was heated to 60-65° C. for 1 hour and then filtered through celite (6.00 g). The celite cake was washed with hot isopropanol (65° C., 2×50 mL) and the filtrate was concentrated under reduced pressure (bath temperature of 50° C.). Isopropanol (40 mL) was added to the residue and the mixture was heated to 80° C. to dissolve the solids. Isopropyl acetate (120 mL) was added and heating was continued to dissolve the precipitate which formed. The solution was cooled to room temperature and stirred for 12 hours. The resulting solid was filtered and dried to give the desired product as a white solid (7.7 g).
Alternatively, the crude product of the hydrogenation reaction was mixed with isopropanol (50 mL) and the mixture was heated to 65-70° C. to dissolve the solids. Acetonitrile (65 mL) was added dropwise via an addition funnel at a rate to maintain the temperature above 55° C. During addition of the acetonitrile, a fluffy gray precipitate formed. After addition of the acetonitrile was complete, the mixture was heated at 65° C. for 30 minutes and then filtered through a pad of celite in a steam jacketed funnel. The filtrate was concentrated and residual acetonitrile was chased with isopropanol (70 mL). The resulting solid was recrystallized from isopropanol/isopropyl acetate (30/90 mL) and after stirring at room temperature for 6 hours, the solid was filtered and dried to give the desired product as a white solid (6.72 g).
EXAMPLE 54
Alternative preparation of (R)-9-[4,4-diethoxy-2-(hydroxymethyl)butyl]-guanine
a) 2-N-Acetyl-6-O-diphenylcarbamoyl-(R)-9-[4,4-diethoxy-2-(hydroxymethyl)butyl]-guanine
To a 50 mL round bottom flask was added 2-N-acetyl-6-O-diphenylcarbamoylguanine (1.10 g, 2.83 mmol) and anhydrous DMF (10 mL). DBU (423 μL, 2.83 mmol) was added and the solid dissolved after stirring for 5 minutes. A solution of the product of Example 14d) (1.0 g, 2.6 mmol) in anhydrous DMF (5.0 mL) was added and the resulting solution was stirred at 45° C. under nitrogen for 28 hours. After cooling to room temperature, the reaction mixture was diluted with ethyl acetate (40 mL) and water (20 mL). The organic layer was separated and washed with a 5% KHSO 4 solution, a saturated sodium bicarbonate solution and brine and then dried over sodium sulfate. The solvent was evaporated under vacuum to provide a light yellow oil, which was chromatographed on silica gel (5% heptane in ethyl acetate) to provide the desired product as a light yellow solid (460 mg).
1 H NMR (300 MHz, CDCl 3 ) ∂ 1.05-1.18 (m, 6H), 1.55-1.68 (m, 2H), 1.92 (s, 3H), 2.40-2.52 (m, 1H), 2.47 (s, 3H), 3.32-3.46 (m, 2H), 3.48-3.62 (m, 2H), 3.89-4.02 (m, 2H), 4.10-4.25 (m, 2H), 4.52 (t, J=5.4 Hz, 1H), 7.05-7.42 (m, 10H), 7.91 (s, 1H), 8.11 (s, 1H)
ESI (−) MS m/z 603 (M−H) − .
b) (R)-9-[4,4-diethoxy-2-(hydroxymethyl)butyl]-guanine
To the product of Example 54a) (100 mg, 0.165 mmol) in a 25 mL round bottom flask was added KOH (62 mg, 0.972 mmol) and water (10 mL). The suspension was refluxed for 20 hours. The reaction mixture was cooled to room temperature and acidified to pH 5 using acetic acid. The solvent was evaporated under reduced pressure to provide the desired product as a white solid.
EXAMPLE 55
2-N-Acetyl-(R)-9-[4,4-diethoxy-2-(hydroxymethyl)butyl]-guanine
To a 50 mL round bottom flask was added 2-N-acetyl-guanine (547 mg g, 2.83 mmol) and the product of Example 14d) (1.0 g, 2.6 mmol). Anhydrous DMSO (10 mL) was added, folowed by DBU (430 μL, 2.88 mmol). The resulting solution was stirred at 40° C. under nitrogen for 24 hours. After cooling to room temperature, the reaction mixture was diluted with chloroform (50 mL) and water (20 mL). The organic layer was separated and washed with water (2×) and brine and then dried over sodium sulfate. The solvent was evaporated under vacuum to provide a light yellow oil, which was chromatographed on silica gel (10% methanol in ethyl acetate) to provide the desired product as a white foam (280 mg).
1 H NMR (300 MHz, CDCl 3 ) ∂ 1.10-1.31 (m, 6H), 1.62-1.85 (m, 2H), 2.06 (s, 3H), 2.44 (s, 3H), 2.50-2.68 (m, 1H), 3.40-3.56 (m, 2H), 3.57-3.73 (m, 2H), 3.96-4.20 (m, 2H), 4.32-4.55 (m, 2H), 4.62 (t, J=5.5 Hz, 1H), 7.82 (s, 1H), 11.60 (s, 1H), 12.40 (s,1H).
EXAMPLE 56
Alternative preparation of (R)-9-[(2-stearoyloxymethyl)-4-(L-valyloxy)butyl]-guanine
To a 500 ml 3-neck round bottom flask equipped with a magnetic stirrer and a temperature probe was added the product of Example 30f) (5.5 g), THF (65 mL) and isopropanol (65 mL). The clear solution was purged three times with nitrogen and 5% Pd/BaCO 3 (0.6 g) was added. The mixture was stirred at 40° C. under a hydrogen filled balloon for 16 hours. The reaction mixture was filtered through celite and the filtrate was evaporated to dryness to provide a white solid. The solid was dissolved in isopropanol (25 mL) at 70° C. and isopropyl acetate (100 mL) was added. The resulting mixture was cooled to room temperature and stirred for 1 hour. The resulting solid was filtered and dried under vacuum to provide the desired product as a white solid (3.39 g).
EXAMPLE 57
Alternative preparation of 2-Amino-6-benzyloxypurine
To a 500 mL 3 neck round bottom flask equipped with a magnetic stirrer, temperature probe and nitrogen inlet was added 2-amino-6-chloropurine (20 g), sodium hyroxide (28 g) and benzyl alcohol (200 mL). The mixture was stirred for 20 minutes and then heated at 100° C. for 2-3 hours. The reaction mixture was then cooled to room temperature and partitioned between methyl t-butyl ether (300 mL) and water (300 mL). The aqueous layer was separated and the pH was adjusted to 7-8 with 6 M HCl. The resulting solid was filtered, washed with water (50 mL) and dried under vacuum at 50° C. for 20 hours to provide the desired product as a pale yellow solid (24.3 g).
EXAMPLE 58
Alternative preparation of (3S)-3-stearoyloxymethyl-4-toluenesulfonyloxy-butyraldehyde
To a 1 liter 3 neck round bottom flask equipped with a magnetic stirrer, temperature probe and nitrogen inlet was added the product of Example 31b) (40 g) and THF (320 mL). The solution was cooled to 20° C. and a solution of trifluoromethane sulfonic acid (20 g) and water (20g) was added. After stirring for 2-3 hours, the reaction mixture was quenched with sodium bicarbonate (12.0 g), followed by addition of methyl t-butyl ether (500 mL). The organic layer was separated and washed with saturated aqueous sodium bicarbonate solution (200 mL), water (200 mL) and brine (200 mL) and then was dried over sodium sulfate. The organic solution was evaporated to dryness under vacuum to give a pale yellow oil which was dissolved in hexane (300 mL) and stirred overnight. The resulting solid was filtered and dried under vacuum to give the desired product as a white solid (25.6 g).
EXAMPLE 59
Alternative preparation of (3S)-3-stearoyloxymethyl-4-toluenesulfonyloxy-butyraldehyde
To a 100 mL 3 neck round bottom flask equipped with a magnetic stirrer, temperature probe and a nitrogen inlet was added the product of Example 31b) (6.5 g), acetic acid (30 mL) and formic acid (20 mL). After stirring at room temperature for 20 minutes, water (20 mL) was added to the mixture and stirring was continued at room temperature for 30 minutes. The resulting precipitate was filtered and dried for 1.5 hours. The solid was added to a 100 mL flask, followed by addition of hexane (90 mL). The mixture was stirred overnight. The resulting solid was filtered and dried at 40° C. udner vacuum for 20 hours to provide the desired product as a white solid (4.6 g).
EXAMPLE 60
Alternative preparation of N-Carbobenzyloxy-L-valine Anhydride
A solution of N-Benzyloxycarbonyl-L-valine (20.0 g) in isopropyl acetate/toluene (1:1.80 mL) was cooled to 0° C. A solution of DCC (8.2 g) in toluene (20 mL) was added slowly, at a rate such that the internal temperature of the reaction mixture was kept below 10° C. The addition funnel was washed with toluene (20 mL). The reaction mixture was stirred for 1 hour and then allowed to warm to room temperature and stirred for another 1 hour. The reaction mixture was filtered and the filter cake was washed with toluene (20 mL). Heptane (120 mL) was added to the filtrate and the resulting solution was cooled to 0-5° C. and stirred for 1 hour. The resulting solid was filtered and washed with heptane (20 mL) and then dried under vacuum at 35° C. for 18 hours to provide the desired product as a white solid (17.0 g).
EXAMPLE 61
Alternative preparation of (R)-9-[(2-stearoyloxymethyl)-4-(L-valyloxy)butyl]-guanine
a) Preparation of (2R)-4,4-Diethoxy-2-stearoyloxymethyl-butanol.
Vinyl stearate (3202 g, 9.375 moles) was charged to a 12 liter 4 neck Morton flask with nitrogen inlet and mechanical stirring. Heating was applied via a 50° C. water bath. As the vinyl stearate melted, the water bath temperature was decreased to 35° C. and stirring was started. Heating and stirring was continued until the vinyl stearate was completely melted. Then the product of Example 14b) (1800 g, 9.375 moles) and Lipase PS30 (45 g, 2.5 wt %) were added. The suspension was stirred at 35-37° C. for 22 hours. The reaction mixture was quenched by additoin of 37.5% methyl t-butyl ether in heptane (2.5 L). The mixture was then filtered through celite and the celite was washed with 37.5% methyl t-butyl ether in heptane (12 L). The organic filtrates were combined and washed with water (10 L) and 23% NaCl solution (10 L). The organic solution was evaporated and methylene chloride was aded (4 L). The solution was evaporated to about half of its original volume. An additional 4 L of methylene chloride was added and the solution was allowed to stand at 5° C. overnight.
b) Preparation of (2S)-4,4-Diethoxy-2-stearoyloxymethyl-butyl toluenesulfonate.
The methylene chloride product solution resulting from Example 61a) was added to a 50 L round bottom flask equipped with mechanical stirring, water condenser, nitrogen inlet and a temperature probe. An additional 4 L of methylene chloride was added, followed by triethylamine (2349 g, 23.2 moles) and p-toluenesulfonyl chloride (2654 g, 13.92 mol). The reaction mixture was stirred for 6 hours without external heating or cooling. Water (1.8 L) was added to the reaction mixture and stirred vigorously for 17 hours. The organic layer was separated and washed with water (10 L). The aqueous layer was extracted with methylene chloride (1 L). The combined organic layers were washed with 7% sodium bicarbonate solution (10 L) and 23% NaCl solution (10 L). The solvent was evaporated to provide the desired product as a thick oil (5947 g).
c) Preparation of (3S)-3-stearoyloxymethyl-4-toluenesulfonyloxy-butyraldehyde.
A suspension of the product of Example 61c) (4573 g, 7.47 mol) in acetonitrile (4 L) was added to a 50 L reactor equipped with a thermocouple and nitrogen inlet. An additional 13 L of acetonitrile was added and the suspension was heated to 37° C. with steam. A solution of triflic acid (1253 mL, 14.16 mol) in water (7.6 L) was added over 20 minutes. Then the mixture was stirred at 39-42° C. for 1 hour. The reaction mixture was quenched by adding it to 20 L of 23% aqueous sodium bicarbonate solution and 35 L of methyl t-butyl ether. The reaction flask was rinsed with 5 L of methyl t-butyl ether and an additional 20 L of 23% aqueous sodium bicarbonate was addded. This mixture was stirred for 10 minutes and the layers were separated. The organic layer was washed with a mixture of 25 L of 23% aqueous sodium bicarbonate solution and 15 L of 7% NaCl solution. Then the organic layer was washed with 25 L of 7% NaCl solution. The solvents were removed on a batch concentrator to provide a thick slurry. Heptane (32 L) was added to the slurry and then evaporated. Additional heptane (12 L) was added and evaporated. A further amount of heptane (40 L) was added and the suspensin was heated to 44° C. in 60 minutes, causing complete dissolution. The reaction flask was cooled to 40° C. in 10 minutes by running cold water over the surface of the flask. The solution was then allowed to slowly cool to 35° C., where cyrstallization occurs. The resulting thick mixture was stirred for 14 hours. The precipitate was filtered and rinsed twice with 4 L of heptane and then dried on the filter funnel for 2 hours and then in a vacuum oven with nitrogen purge for 60 hours at room temperature. The resulting solid (3200 g), heptane (30 L) and methyl t-butyl ether (1.6 L) were combined and heated with stirring to dissolution. The resulting solution was cooled over 1 hour to 42° C. and the resulting suspension was stirred for 20 hours while cooling to room temperature. The precipitate was filtered and dried in a vacuum oven with nitrogen purge for 20 hours at room temperature to give the desired product (2860 g).
d) Preparation of (2S)-4-N-Carbonylbenzyloxy-L-valinyloxy-2-stearoyloxymethyl-butyl toluenesulfonate.
A solution of the product of Example 61c) (511 g, 950 mmol) in THF (2.55 L) was stirred at ambient temperature in a high-pressure reactor with Raney Ni (383 g wet weight) under a 40 psi atmosphere of hydrogen for 2 hours. The suspension was filtered and the filtrate was swirled with magnesium sulfate (250 g) for 1 hour. The organic solution was filtered and added to N-Cbz-L-valine anhydride (598 g, 1.23 mol) and DMAP (5.8 g, 47.5 mmol) and stirred at ambient temperature for 20 hours. The reaction mixture was poured into 5% KH 2 PO 4 (2.5 L) and extracted with methyl t-butyl ether (2.5 L). The organic layer was washed with 10% potassium carbonate (2×2.5 L) and then 23% NaCl solution (2.5 L). The volatiles were evaporated and methyl t-butyl ether (1 L) was added. The volatiles were again evaporated and this procedure repeated (usually about three times) until the Karl-Fischer test indicated less than 1 mole % water. The organic solution was then concentrated and stored as an approximately 65% w/w solution of the desired product.
e) Preparation of 2-Amino-6-iodo-(R)-9-[(2-stearoyloxymethyl)-4-(N-benzyloxycarbonyl-L-valyloxy)butyl]purine.
To a 500 mL flask equipped with a stir bar and a nitrogen inlet was added (2S)-4-N-Carbonylbenzyloxy-L-valinyloxy-2-stearoyloxymethyl-butyl toluenesulfonate (21.8 g, 28.2 mmol), 2-amino-6-iodopurine (9.73 g, 37.3 mmol) and potassium carbonate (11.88 g, 86.1 mmol) slurried in DMF (155 mL). The resulting mixture was stirred for 16 hours at 50° C. The mixture was then cooled to room temperature and poured into 400 mL of ethyl acetate and washed with water (3×400 mL). The aqueous washes were combined and extracted with isopropyl acetate (50 mL). The organic extracts were combined, washed with brine (200 mL), dried over magnesium sulfate and concentrated under vacuum. The residue was dissolved in acetonitrile (150 mL) and washed with heptane. The bottome layer was separated and concentrated. The residue was dissolved in methylene chloride (200 mL). Silica gel (60 g) was added and stirred for 10 minutes. This mixture was poured into a funnel containing 40 g of silica gel. The product was eluted off of the silica gel by washing with 4/1 methyl t-butyl ether/heptane. The filtrate was concentrated to provide the desired product (19.6 g).
f) Preparation of (R)-9-[(2-stearoyloxymethyl)-4-(N-benzyloxycarbonyl-L-valyloxy)butyl]guanine.
Into a 300 mL Fisher-Porter bottle (stirbar/nitrogen) was placed the product of Example 61e) (12.36 g, 14.34 mmol) dissolved in acetonitrile (98 mL) and glacial acetic acid (98 mL), followed by addition of sodium acetate trihydrate (11.70 g, 86 mmol). The resulting mixture was stirred at 120° C. for 4 hours. The mixture was cooled to room temperature and poured into 400 mL of methyl t-butyl ether. The mixture was washed with 5% aq. NaCl (2×300 mL), 2 M potassium carbonate (150 mL), 1% NaHSO 3 (100 mL) and brine (100 mL). The organic layer was concentrated under vacuum. The residue was dissolved in heptane (150 mL) and extracted with acetonitrile (2×100 mL). The top layer (heptane) was concentrated to give the desired product as a thick syrup (8.98 g).
g) Preparation of (R)-9-[(2-stearoyloxymethyl)-4-(valyloxy)butyl]-guanine.
Into a 100 mL shaker was placed (R)-9-[(2-stearoyloxymethyl)-4-(N-benzyloxycarbonyl-L-valyloxy)butyl]guanine (4.53 g, 6.03 mmols) dissolved in isopropanol (45 mL), followed by addition of 4% Pd/C (450 mg). The resulting mixture was shaken under a 5 psi hydrogen for 3 days. The mixture was filtered and concentrated under vacuum to provide a waxy solid. This material was dissolved in hot isopropanol (12 mL) and isopropyl acetate was added (24 mL). The mixture was slowly cooled to 40° C. and then stirred at 0C. for 1 hour. The precipitate was filtered and washed with isopropyl acetate (5 mL) and then dried to provide the desired product (1.53 g).
EXAMPLE 62
Alternative preparation of (R)-9-[(2-stearoyloxymethyl)-4-(L-valyloxy)butyl]-guanine
a) Preparation of (2S)-4-N-t-butyloxycarbonyl-L-valinyloxy-2-stearoyloxymethyl-butyl toluenesulfonate.
A solution of the product of Example 61c) (3.10 g, 5.75 mmol) in THF (50 mL) was stirred at ambient temperature in a high-pressure reactor with Raney Ni (5 g wet weight) under a 5 psi atmosphere of hydrogen for 3 hours. The suspension was filtered and the filtrate was swirled with magnesium sulfate (8 g). The organic solution was filtered and N-Boc-L-valine anhydride (3.11 g, 7.47 mmol) was added, followed by DMAP (0.105 g). The resulting mixture was stirred at ambient temperature for 30 minutes. The mixture was cooled to 0° C. and treated with N,N-dimthylethylenediamine (125 mg). The resulting solution was stirred for 20 minutes and poured into methyl t-butyl ether (100 mL) and was washed with 5% KH 2 PO 4 (100 mL), 1 M potassium carbonate (100 mL) and then 27% NaCl solution (20 mL). The organic solution was then concentrated under vacuum to provide the desired product (3.67 g).
1 H NMR (300 MHz, CDCl 3 ): δ 0.88 (m, 6H), 0.95 (d, 3H), 1.25 (m, 30 H), 1.45 (s, 9H), 1.55 (m, 2H), 1.70 (m, 2H), 2.1 (m,1H), 2.21 (t, 2H), 2.46 (s, 3H), 3.94-4.2 (m, 6H), 5.0 (m,1H), 7.37 (m, 2H), 7.78 (m, 2H). Mass Spec.=740 (M+H) +
b) Preparation of 2-Amino-6-iodo-(R)-9-[(2-stearoyloxymethyl)-4-(N-t-butyloxycarbonyl-L-valyloxy)butyl]purine.
To a 100 mL flask equipped with a stir bar and a nitrogen inlet was added the product of Example 62a) (3.67 g, 4.97 mmol), 2-amino-6-iodopurine (1.68 g, 6.46 mmol) and potassium carbonate (2.05 g, 14.9 mmol) slurried in DMF (27 mL). The resulting mixture was stirred for 16 hours at 50° C. The mixture was then cooled to room temperature and poured into 100 mL of ethyl acetate and washed with KH 2 PO 4 (100 mL containing 20 mL of brine). The organic phase was washed with brine (2×75 mL), dried over magnesium sulfate, filtered and concentrated under vacuum. The residue was dissolved in acetonitrile (20 mL) at 50° C. The mixture was cooled to room temperature and stirred for 2 hours. The precipitate was filtered, washed with acetonitrile (2×5 mL) and dried to provide the desired product (2.79 g).
1 H NMR (300 MHz, CDCl 3 ): δ 0.87 (m, 6H), 0.95 (d, 3H), 1.25 (m, 30 H), 1.43 (s, 9H), 1.6 (m, 2H), 1.74 (m, 2H), 2.1 (m,1H), 2.28 (t, 2H), 2.52 (m, 1H), 4.1-4.4 (m, 6H), 5.03 (m, 1H), 5.22 (s, 1H), 7.73 (s, 1H). Mass Spec.=829 (M+H) +
c) Preparation of (R)-9-[(2-stearoyloxymethyl)-4-(N-t-butyloxycarbonyl-L-valyloxy)butyl]-guanine.
Into a 4 mL vial (stir bar/nitrogen) was placed the product of Example 62b) (0.076 g, 0.092 mmol) dissolved in acetonitrile (0.444 mL) and glacial acetic acid (0.444 mL), followed by addition of sodium acetate trihydrate (0.031 g). The resulting mixture was stirred at 100° C. for 16 hours. HPLC analysis of the mixture indicated that the desired product had been obtained, by comparison with authentic product obtained as described in Example 17b).
d) Preparation of (R)-9-[(2-stearoyloxymethyl)-4-(valyloxy)butyl]-guanine.
Into a 20 mL vial (stirbar/nitrogen) was added (R)-9-[(2-stearoyloxymethyl)-4-(N-t-butyloxycarbonyl-L-valyloxy)butyl]-guanine (0.218 g, 0.29 mmol) dissolved in methylene chloride (3.1 mL) and trifluoroacetic acid (0.33 mL). The resulting mixture was stirred at 25° C. for 14 hours. The mixture was diluted with methylene chloride (10 mL), washed with 7% sodium bicarbonate, dried over magnesium sulfate and concentrated under vacuum to provide the desired product (161 mg).
EXAMPLE 63
Alternative preparation of (R)-9-[(2-stearoyloxymethyl)-4-(L-valyloxy)butyl]-guanine
a) Preparation of (2S)-4-N-allyloxycarbonyl-L-valinyloxy-2-stearoyloxymethyl-butyl toluenesulfonate.
A solution of the product of Example 61c) (15.0 g, 27.7 mmol) in THF (100 mL) was stirred at ambient temperature in a high-pressure reactor with Raney Ni (16 g wet weight) under a 5 psi atmosphere of hydrogen for 3 hours. The suspension was filtered and the filtrate was swirled with magnesium sulfate (8 g). The organic solution was filtered and N-Alloc-L-valine anhydride (13.82 g, 43.3 mmol) was added, followed by DMAP (0.203 g). The resulting mixture was stirred at ambient temperature overnight. The mixture was diluted with methyl t-butyl ether (120 mL) and was washed with 5% KH 2 PO 4 (25 mL), 1 M potassium carbonate (100 mL) and then 27% NaCl solution (20 mL). The organic solution was then concentrated under vacuum to provide the desired product (20.6 g).
1 H NMR (300 MHz, CDCl 3 ): δ 0.88 (m, 6H), 0.95 (d, 3H), 1.25 (m, 30 H), 1.55 (m, 2H), 1.70 (m, 2H), 2.12 (m, 1H), 2.20 (t, 2H), 2.46 (s, 3H), 3.94-4.25 (m, 6H), 4.57 (m, 2H), 5.20-5.35 (m, 3H), 5.90 (m, 1H), 7.45 (m, 2H), 7.79 (m, 2H).
b) Preparation of 2-Amino-6-iodo-(R)-9-[(2-stearoyloxymethyl)-4-(N-allyloxycarbonyl-L-valyloxy)butyl]purine.
To a 500 mL flask equipped with a stir bar and a nitrogen inlet was added the product of Example 63a) (18.43 g, 25.4 mmol), 2-amino-6-iodopurine (8.61 g, 33.0 mmol) and potassium carbonate (10.51 g, 76.2 mmol) slurried in DMF (137 mL). The resulting mixture was stirred for 16 hours at 50° C. The mixture was then cooled to room temperature and poured into 394 mL of isopropyl acetate and washed with water (3×400 mL). The organic phase was washed with brine (200 mL), dried over magnesium sulfate, filtered and concentrated under vacuum. The residue was dissolved in acetonitrile (200 mL). The mixture was stirred for 3 hours at room temperature. The precipitate was filtered, washed with acetonitrile (2×25 mL) and dried to provide the desired product (12.28 g).
1 H NMR (300 MHz, CDCl 3 ): δ 0.89 (m, 6H), 0.98 (d, 3H), 1.29 (m, 30 H), 1.6 (m, 2H), 1.74 (m, 2H), 2.13 (m, 1H), 2.28 (t, 2H), 2.52 (m, 1H), 3.9-4.4 (m, 6H) 4.58 (d, 2H), 5.20-5.35 (m, 3H), 5.90 (m, 1H), 7.76 (s, 1H). Ic Mass Spec.=813 (M+H) +
c) Preparation of (R)-9-[(2-stearoyloxymethyl)-4-(N-allyloxycarbonyl-L-valyloxy)butyl]-guanine.
Into a 60 mL sealed tube (stir bar) was placed the product of Example 63b) (1.00 g, 1.23 mmol) dissolved in acetonitrile (6.0 mL) and glacial acetic acid (6.0 mL), followed by addition of sodium acetate trihydrate (1.00 g). The resulting mixture was stirred at 120° C. for 4 hours. The mixture was cooled to room temperature and poured into 15 mL of methyl t-butyl ether, washed with 5% NaCl (2×15 mL), 2 M potassium carbonate (2×20 mL), 1% NaHSO 3 (2×15 mL) and brine (15 mL). The organic phase was concentrated under vacuum. The residue was chromatographed on silica gel (9/1 methylene chloride/methanol) to provide the desired product as a wax (0.67 g).
1 H NMR (300 MHz, d 6 -DMSO): δ 0.85 (m, 9H), 1.21 (m, 30 H), 1.45 (m, 2H), 1.62 (m, 2H), 1.99 (m, 1H), 2.22 (t, 2H), 2.35 (m, 1H), 3.8-4.0 (m, 4H), 4.12 (t, 2H), 4.46 (m, 2H), 5.15-5.3 (m, 2H), 5.88 (m, 1H), 6.38 (b s, 2H), 7.63 (s, 1H), 10.52 (b s, 1H). Ic Mass Spec.=703 (M+H) +
d) Preparation of (R)-9-[(2-stearoyloxymethyl)-4-(valyloxy)butyl]-guanine.
Into a 4 mL vial (stirbar/nitrogen) was added the product of Example 63c) (0.07 g, 0.10 mmol) dissolved in THF (1.0 mL) and triphenylphosphine (1.6 mg) and Pd 2 (dba) 3 (1.4 mg) and pyrrolidine (0.071 g). The resulting mixture was stirred at 25° C. for 14 hours. The mixture was concentrated under vacuum, diluted with isopropanol and stirred at 4° C. The resulting precipitate was filtered to provide the desired product (33 mg).
Formulation Example A
Tablet Formulation
The following ingredients are screened through a 0.15 mm sieve and dry-mixed
10 g (R)-9-[2-(stearoyloxymethyl)-4-(L-valyloxy)butyl]guanine
40 g lactose
49 g crystalline cellulose
1 g magnesium stearate
A tabletting machine is used to compress the mixture to tablets containing 250 mg of active ingredient.
Formulation Example B
Enteric Coated Tablet
The tablets of Formulation Example A are spray coated in a tablet coater with a solution comprising
120 g ethyl cellulose
30 g propylene glycol
10g sorbitan monooleate
add 1000 ml distilled water
Formulation Example C
Controlled Release Formulation
50 g (R)-9-[2-(stearoyloxymethyl)-4-(L-valyloxy)butyl]guanine
12 g hydroxypropylmethylcellulose (Methocell K15)
4.5 g lactose
are dry-mixed and granulated with an aqueous paste of povidone. Magnesium stearate (0.5 g) is added and the mixture compressed in a tabletting machine to 13 mm diameter tablets containing 500 mg active agent.
Formulation Example D
Soft Capsules
250 g (R)-9-[2-(stearoyloxymethyl)-4-(L-valyloxy)butyl]guanine
100 g lecithin
100 g arachis oil
The compound of the invention is dispersed in the lecithin and arachis oil and filled into soft gelatin capsules.
Biology Example 1
Bioavailability Testing in Rats
The bioavailability of compounds of the invention were compared to the parent compound H2G and other H2G derivatives in a rat model. Compounds of the invention and comparative compounds were administered, per oral (by catheter into the stomach), to multiples of three individually weighed animals to give 0.1 mmol/kg of the dissolved prodrug in an aqueous (Example 4, 5, Comparative example 1-3, 5, 8), peanut oil (Comparative examples 4, 9, 10) or propylene glycol (Example 1-3, 6-12, 17, Comparative example 6, 7) vehicle dependent on the solubility of the test compound ingredient. The animals were fasted from 5 hours before to approximately 17 hours after administration and were maintained in metabolic cages. Urine was collected for the 24 hours following administration and frozen until analysis. H2G was analysed in the urine using the HPLC/UV assay of Ståhle & Oberg, Antimicrob Agents Chemother. 36 No 2, 339-342 (1992), modified as follows: samples upon thawing are diluted 1:100 in aq dist H 2 O and filtered through an amicon filter with centrifugation at 3000 rpm for 10 minutes. Duplicate 30 μl samples are chromatographed on an HPLC column; Zorbax SB-C18; 75×4.6 mm; 3.5 micron; Mobile phase 0.05M NH 4 PO 4 , 3-4% methanol, pH 3.3-3.5; 0.5 ml/min; 254 nm, retention time for H2G at MeOH 4% and pH 3.33,˜12.5 min. Bioavailability is calculated as the measured H2G recovery from each animal averaged over at least three animals and expressed as a percentage of the averaged 24 hour urinary H2G recovery from a group of 4 individually weighed rats respectively injected i.v.jugularis with 0.1 mmol/kg H2G in a Ringer's buffer vehicle and analysed as above.
Comparative example 1 (H2G) was from the same batch as used for preparation of Examples 1 to 12. The preparation of Comparative example 2 (monoVal-H2G) and 3 (diVal-H2G) are shown in Examples 20 and 23. Comparative example 4 (distearoyl H2G) was prepared by di-esterification of unprotected H2G in comparable esterification conditions to step 2 of Example 1. Comparative examples 5 & 8 (Val/Ac H2G) were prepared analogously to Example 4 using acetic anhydride with relevant monovaline H2G. Comparative example 6 (Ala/stearoyl H2G) was prepared analogously to Example 6 using N-t-Boc-L-alanine in step 4. Comparative example 7 (Gly/decanoyl) was prepared analogously to Example 5 but using the step a) intermediate made with N-t-Boc-L-glycine. The preparation of Comparative examples 9 and 10 is shown in Examples 24 and 25 respectively. The results appear on Table 2 below:
TABLE 2
Compound
R 1
R 2
Bioavailability
Comparative example 1
hydrogen
hydrogen
8%
Comparative example 2
valyl
hydrogen
29%
Comparative example 3
valyl
valyl
36%
Example 1
valyl
stearoyl
56%
Comparative example 4
stearoyl
stearoyl
1%
Example 2
valyl
myristoyl
57%
Example 3
valyl
oleoyl
51%
Example 4
valyl
butyryl
45%
Comparative example 5
valyl
acetyl
11%
Example 5
valyl
decanoyl
48%
Example 6
valyl
docosanoyl
48%
Example 7
isoleucyl
stearoyl
53%
Example 8
isoleucyl
decanoyl
57%
Example 9
isoleucyl
myristoyl
49%
Example 10
valyl
4-acetylbutyryl
52%
Example 11
valyl
dodecanoyl
46%
Example 12
valyl
palmitoyl
58%
Example 17
stearoyl
valyl
52%
Comparative example 6
alanyl
stearoyl
23%
Comparative example 7
glycyl
decanoyl
25%
Comparative Example 8
acetyl
valyl
7%
Comparative Example 9
hydrogen
stearoyl
12%
Comparative Example 10
stearoyl
hydrogen
7%
Comparison of the bioavailabilities of the compounds of the invention with the comparative examples indicates that the particular combination of the fatty acids at R 1 /R 2 with the amino acids at R 1 /R 2 produces bioavailabilities significantly greater than the corresponding diamino acid ester or difatty acid ester. For example, in this model, the compound of Example 1 displays 55% better bioavailability than the corresponding divaline ester of Comparative example 3. The compound of Example 4 displays 25% better availability than the corresponding divaline ester.
It is also apparent, for instance from Comparative examples 5, 6 and 7 that only the specified fatty acids of this invention in combination with the specified amino acids produce these dramatic and unexpected increases in pharmacokinetic parameters.
Biology Example 2
Plasma Concentrations in Rats
A plasma concentration assay was done in male Sprague Dawley derived rats. The animals were fasted overnight prior to dosing but were permitted free access to water. Each of the compounds evaluated was prepared as a solution/suspension in propylene glycol at a concentration corresponding to 10 mg H2G/ml and shaken at room temperature for eight hours. Groups of rats (at least 4 rats in each group) received a 10 mg/kg (1 ml/kg) oral dose of each of the compounds; the dose was administered by gavage. At selected time points after dosing (0.25, 0.5, 1, 1.5, 2, 4, 6, 9, 12, 15, and 24 hours after dosing), heparinized blood samples (0.4 ml/sample) were obtained from a tail vein of each animal. The blood samples were immediately chilled in an ice bath. Within two hours of collection, the plasma was separated from the red cells by centrifugation and frozen till analysis. The components of interest were separated from the plasma proteins using acetonitrile precipitation. Following lyophilisation, and reconstitution, the plasma concentrations were determined by reverse phase HPLC with fluorescence detection. The oral uptake of H2G and other test compounds was determined by comparison of the H2G area under the curve derived from the oral dose compared to that obtained from a 10 mg/kg intravenous dose of H2G, administered to a separate group of rats. The results are depicted in Table 1B above.
Biology Example 3
Bioavailability in Monkeys
The compounds of Example 1 and Comparative example 3 (see Biology Example 1 above) were administered p.o. by gavage to cynomolgus monkeys.
The solutions comprised:
Example 1 150 mg dissolved in 6.0 ml propylene glycol, corresponding to 25 mg/kg or 0.0295 mmol/kg.
Comparative 164 mg dissolved in 7.0 ml water, corresponding to
Example 3 23.4 mg/kg or 0.0295 mmol/kg.
Blood samples were taken at 30 min, 1, 2, 3, 4, 6, 10 and 24 hours. Plasma was separated by centrifugation at 2500 rpm and the samples were inactivated at 54° C. for 20 minutes before being frozen pending analysis. Plasma H2G levels were monitored by the HPLC/UV assay of Example 30 above.
FIG. 1 depicts the plasma H2G recovery as a function of time. Although it is not possible to draw statistically significant conclusions from single animal trials, it appears that the animal receiving the compound of the invention experienced a somewhat more rapid and somewhat greater exposure to H2G than the animal which received an alternative prodrug of H2G.
Biology Example 4
Antiviral Activity
Herpes simplex virus-1 (HSV-1)-infected mouse serves as an animal model to determine the efficacy of antiviral agents in vivo. Mice inoculated intraperitoneally with HSV-1 at 1000 times the LD 50 were administered either with a formulation comprising the currently marketed anti-herpes agent acyclovir (21 and 83 mg/kg in a 2% propylene glycol in sterile water vehicle, three times daily, p.o.) or the compound of Example 29 (21 and 83 mg/kg in a 2% propylene glycol in sterile water vehicle, three times daily, p.o.) for 5 consecutive days beginning 5 hours after inoculation. The animals were assessed daily for deaths. The results are displayed in FIG. 2 which charts the survival rate against time. In the legend, the compound of the invention is denoted Ex.29 and acyclovir is denoted ACV. The percentage of mice surviving the HSV-1 infection was significantly greater following a given dose of the compound of the invention relative to an equivalent dose of acyclovir.
The foregoing is merely illustrative of the invention and is not intended to limit the invention to the disclosures made herein. Variations and changes which are obvious to one skilled in the art are intended to be within the scope and nature of the invention as defined in the appended claims. | Methods and novel intermediates of the formula:
wherein R 6 and R 7 are lower alkyl or benzyl or R 6 and R 7 taken together are —CH 2 CH 2 —, —CH 2 CH 2 CH 2 — or —CH 2 CH 2 CH 2 CH 2 CH 2 —, R 8 is C 1 -C 21 alkyl or a C 2 -C 21 monounsaturated alkenyl, which may optionally be substituted with substitution substituents independently selected from the group consisting of hydroxy, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, C 1 -C 6 alkoxy C 1 -C 6 alkyl, C 1 -C 6 alkanoyl, amino, halo, cyano, azido, oxo, mercapto and nitro, and R 9 is an alcohol protecting group. The intermediates are useful for the preparation of acyclic nucleoside derivatives of the formula:
where one of R 1 and R 2 is an amino acid acyl group and the other of R 1 and R 2 is a —C(O)C 3 -C 21 saturated or monounsaturated, optionally substituted alkyl and R 3 is OH or H; or a pharmaceutically acceptable salt thereof. | 8 |
CROSS REFERENCE TO RELATED APPLICATION
This application is a Continuation-in-Part of patent application Ser. No. 11/818,044, filed on Jun. 13, 2007, now abandoned.
FEDERALLY SPONSORED RESEARCH
Not Applicable
NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT
Not Applicable
INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC
Not Applicable
FIELD OF THE INVENTION
This invention relates to methods of reinforcing and attaching the edges of a textile panel such that they are able to convey loads into a secondary structure such that the load is resisted, energy is transferred, and the panel does work. Primarily, load bearing articles made of textiles are designed to work in tension, where the strength and orientation of fibers are a determining factor in how the article is used, and the method to transition loads into a secondary structure is a determining factor in the load bearing capacity of the article. Articles such as lifting devices, tension structures and protective barriers such as blast screens and hurricane shutters are examples of products where the tensile strength and lightweight properties of modern textiles have been used to create new products.
BACKGROUND OF THE INVENTION
For millennia, man has used woven textile goods for a variety of domestic and industrial applications. To enable woven materials to be put to use, techniques were developed to reinforce the edges such that the textile could be attached to a secondary structure to do work. As an example, seafarers from antiquity developed the durable techniques of sewing attachment straps and using grommets on those reinforced edges that allowed cloth panels to be affixed to a secondary structure such as a mast and connected to a pole or control rope to drive a vessel through the water by the force of wind. Two principle factors limited the ability of a sail to transfer the potential wind energy into a force to drive a vessel: the first being the strength of the cloth; the second being the method used to reinforce the edge and affix the sailcloth to the support structure. While today these traditional techniques are widespread, it was over much of the course of known history that these methods were developed.
The range of applications for industrial textiles prior to the development of modern synthetic materials was self limiting. Natural fibers could be made no stronger than their natural state. The techniques based on principles of sewing hems to reinforce the edge and attaching grommets or straps to fasten the textiles made from these fibers were largely sufficient, as the strength of these methods of reinforcement and attachment often exceeded the strength of the fibers in the textile itself. The only way to make a stronger textile panel was to increase the quantity of fibers in the textile. Textiles of natural fibers quickly became impractical for many high load applications which naturally limited the development of additional uses and methods of attachment. The rise of modern synthetic fibers yielded textiles that are far stronger than textiles of natural fibers and have resulted in a vast number of new and innovative products.
Current art describes a range of textile devices intended for load applications which use some form of the traditional methods to reinforce and attach the edges. U.S. Pat. No. 6,176,050 issued to Gower and U.S. Pat. No. 6,959,748 issued to Hudoba show examples of textiles used as a hurricane barriers. Gower uses straps sewn onto a hemmed and stitched edge, while Hudoba uses grommets on an edge reinforced by welding a second strip of material. Similar to Gower, U.S. Pat. No. 4,781,473 issued to LaFleur shows straps for lifting sewn onto a large flexible material bulk container whose edges have been reinforced with layered and stitched hems. Similar to Hudoba, U.S. Pat. No. 5,529,321 issued to Thompson shows a hauling harness for a load carrying tarp which has double layer reinforced edges with grommets. U.S. Pat. No. 7,216,908 issued to Daigle, shows a textile lift bag used to load and unload bulk materials more easily; its edges are hemmed and reinforced with sewn on webbing to which lift straps are sewn. U.S. Pat. No. 4,290,243 issued to Mellin discloses a method of attaching a fabric used in tension structures; this system reinforces the edge of the textile with a hemmed in cable, which is then used as an attachment point for the secondary structure.
The applications listed above demonstrate uses for textiles using traditional methods to secure the reinforced the edge of the textile and attach it to a secondary structure. While these current methods of sewn or welded hems to reinforce edges using straps or grommets to transfer loads are generally successful in moderate load applications, they do not perform as well as possible. Point loading tends focus the load to a limited number of fibers within the panel around the points of attachment such as grommets or straps. This places a greater strain on the fibers directly in line with the grommet or strap making these fibers vulnerable to failure. Additionally, distortion occurs along the border edges as the few fibers aligned with the anchor points bear the greatest percentage of the load. Compounding failures occur across the reinforced edge as the highly tensioned fibers break, causing shock loads to the remaining fibers which cause them to break as well.
Another family of current art uses better load distribution along the edge of the load bearing textile. U.S. Pat. No. 5,915,449 issued to Schwartz describes a textile blast screen which uses a hemmed in rod to reinforce the top and a hemmed in lead weight to reinforce the bottom; these also serve as attachment points. U.S. Pat. No. 5,746,343 issued to Waltke et al shows a textile bag for liquids supported by having its edges sewn onto a frame. Similarly, U.S. Pat. No. 5,329,719 issued to Holyoak shows a textile containment method for raising and harvesting fish in a body of water having edges that are also sewn onto a frame. While these products have less likelihood of failure at the attachment point and less likelihood of distortion because the loads are better distributed across the panel, the sewn hem is still a potential point of failure. When structural elements are comprised of stitched materials, the panel is subject to stress failure due to shear loading of the stitch. Further still, the process of stitching fabric inherently weakens the textile. Damage to the thread itself, whether by abrasive action or ultraviolet degradation is a concern to manufacturers and consumers of load bearing textile devices. The difficulty is in identifying the progressive degradation and establishing a time period and protocol by which the effective service life of the device can be determined. Additionally, current art disclosures that rely on traditional methods of manufacture are not able to take advantage of labor saving manufactured components and are therefore required to have skilled labor, large facilities and complex machinery to produce a reliable and consistent product. Ultimately these disadvantages increase consumer costs and make the products less desirable. Additionally still, no part of a sewn seam or grommet assembly can be reused nor is it easily repaired in the field.
Current art shows that industry has recognized these problems and has set forth a range of textile clamps and attachment methods which attempt to address the issues above. U.S. Pat. No. 4,686,748 issued to Kaivanto, U.S. Pat. No. 5,692,272 issued to Woods, and U.S. Pat. No. 5,168,605 issued to Bartlett each show a clip for holding fabric. While these clips are all improvements over sewn methods, they still describe single points of attachment that are subject to the same point loading concerns previously noted. In order to distribute loads evenly across the terminating edge, an excess of these textile clamps would be required. U.S. Pat. No. 2,266,466 issued to Linder sought to remedy the issue of point loading and the requirement for skilled labor to assemble chair seats. Linder describes a continuous strip of material worked in such a way to form a clamping jaw, where the jaw interacts with a rod and fabric to form a textile clamp. In use the clamping jaw is first held closed by a series of rivets then the clamp is secured to a chair frame with a fastener. One drawback of Linder is the requirement of punching multiple holes to secure the strip to the textile making it a labor intensive operation requiring specialized tools and not practical for use in the field. Another drawback is the inability to mass manufacture a functional item in a single piece.
Limited to methods described in prior art for securing a textile panel to a secondary structure, industry is not able to take full advantage of the strength of modern fibers in high load applications. What is needed is a method to further increase the load carrying capacity of an article made of high strength synthetic fibers which may be applied/affixed/deployed without the need for specialized skill, facilities or tools.
BRIEF SUMMARY OF THE INVENTION
The invention describes a load bearing textile clamp that, in conjunction with a textile sheet, forms a load bearing textile panel. It is removably attached and can be configured and reconfigured to a number of applications having the qualities of lightness, strength, flexibility and durability.
Several objects and advantages of the present invention are:
(1) To provide a device that maximizes the use of the fiber strength in textiles, particularly those made from modern synthetic fibers. (2) To provide a device that serves as an intermediary between a textile sheet and a secondary structure which is incorporated into the edge of the textile sheet forming a textile panel that accumulates loads which can then be transferred to a secondary structure. (3) To provide a device that can be attached to textile sheets quickly without tools or fasteners minimizing time and cost of assembly. (4) To provide a simple device that can be used by non skilled individuals. (5) To provide a device that is durable and weather resistant. (6) To provide a device that is reusable. (7) To provide a device that enables textiles to be used in new and innovative ways. (8) To provide a device that is inexpensive to manufacture. (9) To provide a device that is modular, and can be used in part, as a whole, or in combination with other devices. (10) To provide a device that is lightweight, compact, and easy to store when not in use. (11) To provide a device that does not require specialized equipment, fabrication facilities, or methods of assembly such as sewing machines, welding, adhesives, or other means to secure it to the textile. (12) To provide a device that is capable of being used with a wide range of textiles. (13) To provide a device used in high load applications such as large tents, trucking tarps, heavy lift tarpaulins, etc. For example, this invention may be used in the hurricane protection industry where high strength textiles are used as hurricane shutters and storm panels in any manner of situations where they serve to cover windows, doors, open areas and even roofs to block wind, debris impacts or serve as mechanical resistors to uplift forces or direct wind pressures.
Further objects and advantages will become apparent from a consideration of the ensuing description and drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
In the drawings, repeat figures have the same number.
FIG. 1 shows a perspective view of a series of clamps attached to a textile sheet forming a textile panel.
FIG. 2 shows a close-up view of a clamp without the rod.
FIG. 3 shows a close-up view of a clamp showing how the textile sheet and rod are inserted and part of the locking mechanism.
FIG. 4 shows a close-up view of a clamp, textile sheet, and rod locked together.
FIG. 5 shows a top view of the unfolded clamp.
FIG. 6 shows a side view of the unfolded clamp with details of the locking mechanism, the arrow indicates how the clamp is closed.
FIG. 7 shows a cross section of a closed clamp with locking mechanism engaged.
FIG. 8 shows a cross section of a closed clamp showing the textile sheet and rod are held within the clamp.
DRAWINGS
Reference Numerals
12
Rod
14
First Hole
16
Living Hinge
18
Lip
20
Second Hole
22
Catch
24
Textile Sheet
26
Neck
28
Textile Sheet Hole
30
First Curved Section
32
Second Curved Section
34
First Flat Side
36
Second Flat Side
DETAILED DESCRIPTION OF THE INVENTION
This invention describes an intermediary device between a textile sheet and a secondary structure which allows a textile sheet to perform as a load bearing panel. The invention replaces the typical and laborious task of gluing and/or sewing reinforcements and/or affixing grommets and/or riveted plates into textile sheets to create a load bearing edge.
These goals are achieved by the invention by wrapping the edge of a textile sheet around a rod and securing the rod and textile within a locking clamp. The clamp is comprised of a thin rectangular component with a living hinge in the center and with complementary flat sides and curved sections to hold a rod, and complementary surfaces integrated into a hole in the clamp to create a locking mechanism. The first hole in the clamp is elongated on one side forming a neck with a lip; the second hole is enlarged to receive the neck and has a catch for the lip. When folded on itself, the rectangle forms a U-shaped sleeve that becomes a compressive clamp around the rod and textile once the locking mechanism is engaged. To apply the clamp to a textile sheet, the edge of the textile is folded around the rod with sufficient overlap, a hole is made in the textile where the fastener will be and then the rod and textile are inserted into the curved sections of the U-shaped sleeve. As the two flat sides of the U-shaped sleeve are pressed together, curved sections hold the rod, and the locking mechanism is engaged through the hole in the textile and the clamp is secured to the textile sheet forming the load bearing edge of a panel. The elongated neck of the first hole of the clamp conceals the hole cut in the textile for a professional finish. The first and second holes also form an opening where an anchoring fastener can be inserted to secure the panel to a substrate. In use a series of clamps are placed along the edge of textile sheet and rod, the number and spacing of the clamps in relation to the size of the panel determines the load capacity of the panel.
The textile clamp is of such size as to be easily managed. However, the invention could be made larger or smaller, longer or shorter, and multiple assemblies can be placed end-to-end as required by the application.
In manufacturing, it is preferred that the clamp is manufactured as a single unit by injection molding utilizing a durable thermoplastic with high resiliency. It is preferred to use materials resistant to UV and other forms of degradation. Further, it is preferred that the rod is comprised of a material with high resiliency and resistant to compression. While these materials and methods are preferred embodiments of the invention, other materials and methods maybe used to more efficiently produce the parts and the future may yield new materials that may enhance performance. Any of these improved items may be incorporated into the invention without altering the spirit of the invention.
While the invention offers a solution primarily for use in the construction of high load bearing textile panels such as textile-based hurricane panels to protect windows and other openings, the clamp has many other uses in many fields of endeavor where industrial textiles are currently used; such as commercial fishing, fish farming, tent and tarpaulin manufacturing and repair, riparian management, land stabilization, commercial awnings, billboards, signage, sail making, oil and agriculture industry, ocean engineering, and others. Nothing should be construed from this description to limit the scope of this invention. | A removable load bearing textile clamp including a locking clamp portion configured to accept an internally positioned rod such that a textile sheet can be led around the rod and positioned inside the clamp and secured by closing the clamp and engaging the locking mechanism. | 4 |
CROSSREFERENCE TO RELATED APPLICATION
This is a continuation-in-part of application Ser. No. 07/121,571 filed Nov. 16, 1987, now U.S. Pat. D. 346.678.
BACKGROUND OF THE INVENTION
This invention relates to a timing device for a barbecue grill unit. More particularly, the invention relates to a handle and timing assembly for a gas barbecue grill wherein a timing unit is integrally mounted in the handle for ease of observation and for prevention of mishandling or loss of the timing mechanism.
There is not readily available a timing device for barbecue grills wherein the timing unit is integrally mounted with the grill unit. There are available cooking pots or pans with mounted timing devices. For example, in U.S. Pat. No. 2,192,600, a whistling type timing mechanism is positioned in the cover of a cooking vessel. A clock escapement mechanism is utilized whereupon reverse movement moves a bar-like member 10 with an opening 11 for orientation with another opening 9 so as to produce a whistle effect at the conclusion of the timed period. A lid mounted timing device for a cooking utensil is also disclosed is U.S. Pat. No. 4,451,156. In this device, bell or alarm type mechanisms of a well-known type are enclosed in two cups 3 and 4. A window 5 is provided in an upper cup 3 having a marking and the set time of a short-time bell read on a scale provided on the lower cup 4. A timing device for cooking meat on an outdoor grill is disclosed in U.S. Pat. No. 3,732,468 and the device includes an electronic circuit adapted to approximate the usual timing of the outdoor charcoal-grill type cookery. A computer controller type cooking device is also described in U.S. 3,783,769 to determine the cooking of meat to a desired degree.
It is an advantage of the present invention to provide a timing type mechanism for a barbecue grill wherein the timing device is integrally mounted therewith.
It is another advantage of this invention to provide a combined handle and timing device for a barbecue grill wherein the timing device is readily observable.
It is yet another advantage of this invention to provide a timing device of the foregoing type which is readily associated with the grill unit yet is not adversely affected by the heat from the grill.
It is still another advantage of this invention to provide a timing mechanism for a gas barbecue grill which can be readily adapted to a handle member so that it can be produced in an economical manner.
SUMMARY OF THE INVENTION
The foregoing advantages are accomplished and the shortcomings of the prior art overcome by the handle and timer assembly for a barbecue grill as described herein. The handle and timer assembly includes a handle member having a hand gripping portion composed of heat insulating material. There are means operatively associated with the handle member to attach the handle member to an exterior wall portion of the grill. A timing mechanism of the self energizing type is connected to the handle member at a location on the handle member spaced from the attachment to the grill wall.
In one embodiment, there is an inner compartment in the handle portion and a timing mechanism of the self-energizing type is accommodated in the compartment with at least a portion of the timing mechanism secured therein. A housing member with time indicating characters thereon covers the timing mechanism to provide a timing device with the housing member arranged to rotate with respect to the handle portion.
Preferably, the housing member is partially accommodated in a recessed portion disposed adjacent to and outwardly of the inner compartment. In order to minimize exposure of the timing device to heat generated from the grill unit, the handle portion is of a length to accommodate a human hand when the hand is positioned in a finger and palm gripping position with the timing device being spaced at the end of the handle and away from the attachment to the barbecue grill cover. The handle portion is preferably of a wooden composition.
In one aspect, the housing member includes a cap portion which is arranged to enclose the timing mechanism which is of the manual, spring winding type. To accommodate the handle and timer assembly the cover of the barbecue grill can include a boss member to provide for sturdy attachment. The handle and timer assembly of this invention is especially suitable for use in conjunction with the barbecue grill which is of the gas fuel type.
In other embodiments, the timing mechanism is connected to the handle at the side of the cover of the barbecue grill or at the front of the cover. When connected at the front of the cover the timing mechanism can be positioned in an upwardly or forward position.
BRIEF DESCRIPTION OF THE DRAWINGS
A better understanding of the present handle and timer assembly will be accomplished by reference to the drawings wherein:
FIG. 1 is a perspective view of a gas barbecue grill unit showing the handle and timer assembly secured to the cover thereof.
FIG. 2 is an enlarged view in side elevation of the handle and timer assembly with a portion of the grill cover shown in vertical section as well as the means of attaching the handle assembly to the grill cover.
FIG. 3 is an assembly view of the handle and timer assembly shown in FIG. 1.
FIG. 4 is a view in vertical section taken along line 4--4 of FIG. 3.
FIG. 5 is a view in vertical section taken along line 5--5 of FIG. 3.
FIG. 6 is a view similar to FIG. 1 showing an alternative embodiment.
FIG. 7 is an assembly view of the embodiment shown in FIG. 6.
FIG. 8 is a view in vertical section taken along line 8--8 of FIG. 7.
FIG. 9 is a view similar to FIG. 1 showing yet another alternative embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Proceeding to a detailed description of the present invention and particularly referring to FIG. 1, the handle and timer assembly generally 10 is shown in conjunction with a gas-fired barbecue grill generally 11 which has the usual cover 12 mounted over the usual base 13. A control panel 14 is also provided at the lower front of the base 13 and has the control knobs 15 for controlling a gas supply from a gas supply tank 17 positioned on the base 18. A support post 16 mounts the base 13 of the grill 11 on the pedestal 18.
Referring specifically to FIGS. 2 and 3, the handle and timer assembly 10 includes a handle portion 19 preferably of a wooden composition. A boss 20 is provided on the side wall 38 of the cover 12 and has a passage 39 which will accommodate the threaded stud 21 mounted in the handle portion 19. The threaded stud 21 is engaged by the threads of the nut 22. As best seen in FIG. 3, handle portion 19 has a large diameter compartment 23 which will accommodate at least a portion of the timing mechanism 25. Timing mechanism 25 is of a standard, manual, spring winding type with the usual escapement mechanism and is readily available from the Robert Shaw Controls Co. of Waterbury Conn. Preferably, two mounting bolts 26 extend from the timing mechanism 25 and will be accommodated in the threaded portions 27 of the handle portion 19. A slotted stem 28 extends from the timing mechanism opposite the handle portion 19 for engagement with the projection 30 integrally positioned in an annulus 32 disposed inside the housing cap 29. A flange 31 circumferentially extends from the housing cap 29 and is partially accommodated by the annular recessed portion 24 provided on the handle 19 and adjacent the compartment 23.
As best seen in FIG. 4, an annular wall member 40 divides the inner compartment 23 from the outside recess 24 of the handle portion 19. A smaller diameter inner compartment 34 is also disposed in the handle portion 19 to receive a housing projection 35 of the timing mechanism 25.
FIG. 5 shows the connection of the stabilizing bars 41, 42, 43 and 44 of the housing cap 29 with the inner annular member 32. This gives rigidity to the winding projection 30 and a readily available arrangement.
FIGS. 6-9 illustrate alternative embodiments generally 110 and 210 wherein the same or similar components are indicated by the same reference numbers except in the "100" and "200" series.
Referring to FIGS. 6-8, it is seen that the handle and timer assembly 110 is positioned from the front wall 145 of the cover 112. The handle is fastened to the front wall 145 of the cover 112 in a stand off position by the standoffs 151 and the bolts 152. In this embodiment, the timing mechanism 125 and accordingly the marked housing cap 129 is positioned in an upwardly facing position. This particular embodiment employs a timer housing 146 with a recess 147 to accommodate cap flange 131. Housing 146 also has a compartment 148 with a central opening 154 and passages 149 and 153 to accommodate housing projection 135 and mounting bolts 126, therethrough.
As seen in FIG. 9 handle and timer assembly 210 is the same as timer assembly 110 except the timing mechanism (not shown but housed in housing cap 229) is positioned in a forward position as indicated by the housing cap 229.
Operation
A better understanding of the advantages of the handle and timer assembly 10 will be had by a description of its assembly and operation. As indicated in conjunction with FIG. 3, a portion of the timing mechanism 25 can be readily positioned in the compartment 23 with the threaded mounting bolts 26 secured in the threaded portions 27 and the housing projection 35 positioned in the inner compartment 34. The housing cap 29 is then positioned over the timing mechanism 25 as well as a portion of the recess 24 with the projection 30 positioned in the slotted stem 28. This engagement of the projection 30 in the slotted stem 28 will not only permit a rotation of the stem 28 by the cap 29 but also a frictional holding of the cap 29 on the timing mechanism 25. The combined timer and handle assembly 10 can then be packaged as a separate unit for later attachment to the cover 12 of the barbecue grill 11 and the mounting boss 20. Alternatively, the timer and handle assembly 10 can be mounted as an original equipment component and supplied with the grill. In either event, the combined handle and timer assembly 10 is readily attached to the side wall 38 of the grill 11 by placement on the boss 20 with the threaded stud 21 extending therethrough and attached to the inside of the cover 12 by the threaded nut 22.
When it is desired to actuate the timer mechanism 25, all that is required is a rotation of the housing cap 29 to an indicated degree so as to align the selected timing numerals 33 on the cap 29 with the reference marker stop 37 disposed on the handle 19. This movement will automatically wind the spring and an escapement mechanism in the timing mechanism 25. The cap will then rotate in an opposing direction back to a position with the pointer portion 36 on the cap 29 aligned with the reference marker stop 37. At this time a bell will sound and the operator will know that the designed time has expired. The cover 12 can be conveniently opened by means of the handle 19 and the items which have been cooked in the grill 11 may be removed or cooked for an additional period of time.
The assembly and operation of handle and timer mechanisms 110 and 210 are essentially the same as described for mechanism 10. One difference is the attachment of the timing mechanism 125 to the handles 119 and 219. This is effected by the timer housing 146 which affords connection of the timing mechanism 125 therethrough which is partially accommodated in the compartment 148 when the mounting bolts 126 are fastened into the threaded portions 127 and the housing projection 135 is accommodated in handle compartment 134.
Mechanisms 110 and 210 offer the adventage of having the timing mechanisms such as 125 and the marked housing caps 129 and 229 positioned at the front of the barbecue grills 111 and 211, respectively. This can afford easier readability.
It will be readily apparent that one of the advantages of having the combined handle and timing mechanisms is that they are utilized as a handle as well as a timing unit. The timing mechanisms are fixedly mounted in the handles 19, 119 and 219, yet are positioned away from the source of heat. This positioning is advantageous in two respects: First, the handle is disposed at the side or the front of the cover 12 such as from the walls 38 and 145 and located away from the heat source; second, the timing mechanisms and the caps 29, 129 and 229 are insulated from the barbecue grill units 11, 111 and 211 by the insulated handles 19, 119 and 219. Another important feature is the fact that the timing devices are integrally mounted to the handle so that they will not be inadvertently misplaced during the cooking operation or dropped onto a patio surface or into the cooking area of the grill.
Handles 19, 119 and 219 are preferably composed of a wooden material. However, if desired, the handles could be composed of a heat resistant plastic material or coiled metal. The housing caps 29, 129 and 229 are composed of a rigid plastic material; however, they could be composed of any suitable material. While the preferred means of attaching the handles 19, 119 and 219 to the barbecue grill 11 is with a threaded attachment such as 21 and 22, or 152 and 252, any type of suitable fastening means whether of the threaded or adhesive variety could be employed. Alternatively, in the instance of a coiled metal handle it could be welded thereto. The gas fired barbecue grill 11 is fabricated from cast aluminum. However, the handle and timing mechanism of this invention can be utilized to advantage with grills manufactured from various materials as well as grill units using various types of fuel such as charcoal.
It will thus be seen that through the present invention there is now provided a combined handle and timer assembly which will afford the ready observation of the timing device. In addition, the handle and timer assembly obviates a problem of heat coming in direct contact with the operator's hand in that it is in a spaced position from the front or side wall of the grill unit and away from the heat source during the opening of the cover. The handle and timer assembly is adaptable to various types of timing mechanisms which can be readily adapted to a handle for opening or closing a grill cover.
The foregoing invention can now be practiced by those skilled in the art. Such skilled persons will know that the invention is not necessarily restricted to the particular embodiment presented herein. The scope of the invention is to be defined by terms of the following claims as given meaning by the preceding description. | A handle and timer assembly for a barbecue grill wherein the time that a cooking operation is taking place can be readily ascertained and is integrally mounted with a handle for opening the cover of the barbecue grill. The timing mechanism is preferably of a spring winding type and is mounted on the handle at a location spaced from the attachment to the grill. This not only affords a timing mechanism for cooking in conjunction with the grill wherein heat transfer to timing mechanism is kept to a minimum but also prevents the timing mechanism from being misplaced or inadvertently dropped as well as not being subjected to excessive heat. | 6 |
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