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FIELD OF TECHNOLOGY
[0001] This invention is about a process for preparing a branched polymer with a new type free radical polymerization initiator, belonging to the fields of polymer synthesis and preparation of functional polymers.
BACKGROUND
[0002] (Hyper) branched polymers, with the characteristics of low viscosity, high dissolvability and high degree of functionality because of their unique 3D spherical structure, are believed to be amenable for extensive use as viscosity modifier of polymer melt in a number of fields, to prepare coating materials and adhesives with high solids content, carriers of drugs, catalysts, and liquid crystal polymers and photoelectrical materials. It has become a popular subject in the polymer science, as their prospects of application have attracted large numbers of domestic and overseas experts and scholars to investigate them.
[0003] Currently, the main processes to synthesizing vinyl branched polymers are live polymerization and conventional free radical polymerization with chain transfer agent. However, live polymerization requires very severe reaction conditions, and the polymerization reaction cost is very high, with limited types of suitable monomers. Compared with live polymerization, conventional free radical polymerization reaction is simple and easy, however, the conventional free radical polymerization reaction systems reported are quite complicated, and large amount of additional agent should be added; the (hyper) branched polymers obtained from the synthesis have low molecular weight with wide distribution; the branching points of the products are weak chemical bonds; the branched monomers themselves are extremely unstable, and the speed and degree of potential branched monomers releasing branched groups are restricted by several factors. These deficiencies have seriously restricted the theoretical research and scaled applications of vinyl branched polymers.
[0004] Discovering a simple and cheap synthesizing processes is an important orientation of research of vinyl branched polymers. In this invention, a new type of free radical polymerization initiator containing a polymerisable double bond and peroxide bond is designed to synthesize vinyl monomers into branched polymers under the conventional free radical polymerization, without addition of branched monomer. This invention has important significance to the theoretical research and scaled applications of (hyper) branched polymers.
SUMMARY
[0005] This invention has made public a new type of free radical polymerization initiator, which is used to prepare (hyper) branched polymers under the conventional free radical polymerization, without the addition of branched monomer. An aspect relates to the use of a new type of free radical polymerization initiator containing both polymerisable double bond and peroxide bond with good storage stability, which can be used to synthesize the branched polymers under conditional free radical polymerization without addition of branched monomer and other assist initiators. This synthesizing process to prepare (hyper) branched polymers is simple and practical, and can be used at low production cost.
[0006] A process to prepare branched polymers in the following steps: polymerization is performed under the conventional free radical polymerization with the compound containing both the peroxide group and a polymerisable double bond as an initiator and branched monomer, vinyl compound as monomer, in which the molar ratio of initiator and monomer is 1:2˜200, and the mass ratio of solvent and monomer is 0˜1.5:1, the polymerization reaction temperature is controlled in a temperature range of 60˜100° C., and the polymerization reaction time is controlled in a range of 8˜40 hours. The peroxide compound containing a polymerisable a double bond is used as initiator and branched monomer used is peroxide (methyl) acrylate containing a polymerisable double bond, with the structural formula as follows:
[0000]
[0000] In which R is —CH 3 or
[0000]
[0007] The solvent is toluene, benzene or xylene, etc.
[0008] The vinyl monomer is styrene, methacrylic acid monomer, methyl acrylate monomer, propylene derivatives or vinyl acetate monomer.
[0009] The polymerization system can be homopolymerization or copolymerization of vinyl monomers.
[0010] The polymerizing process can be solution polymerization or bulk polymerization.
[0011] The creativity and novelty of this invention: the new type of free radical polymerization initiator contains both polymerisable double bond and peroxide bond with good storage stability, which can be used to synthesize the branched polymers under conditional free radical polymerization without addition of branched monomer and other assist initiators. This synthesizing process to prepare (hyper) branched polymers is simple, feasibile and can be used at low production cost. The degree of branching is can be controlled by adjusting the ratio of initiator to monomer, the polymerization reaction conditions are extremely simple, the operability is good, the monomer conversion rate in polymerization reaction is high, and the cost of polymer production is low.
BRIEF DESCRIPTION
[0012] FIG. 1 shows the trend of variation of the intrinsic viscosity of the branched polymer obtained in embodiments 1 and 3 and the corresponding linear polymer vs molecular weight, with linear polystyrene (⋆), [styrene]:[tert-butyl peroxide methacrylate]=100:0.5 (□), [styrene]:[isopropylphenyl peroxide methacrylate]=100:0.5 (Δ).
[0013] FIG. 2 shows the trend of variation of the branching factor g′ of the branched polymer obtained in embodiments 1 and 3 vs molecular weight, with [styrene]:[tert-butyl peroxide methacrylate]=100:0.5 (□), [styrene]:[isopropylphenyl peroxide methacrylate]=100:0.5 (Δ) (g′ is the ratio of intrinsic viscosity of branched polymer and linear polymer with the identical molecular weight g′=IV branched /IV linear ; the smaller g′ the higher degree of branching).
[0014] FIG. 3 shows the trend of variation of the branching factor g′ of the branched polymer obtained in embodiments 5, 6 and 7, [MMA]:[tert-butyl peroxide methacrylate]=100:0.5 (∘), [MA]:[tert-butyl peroxide methacrylate]=100:0.5 (∇), [VAc]:[tert-butyl peroxide methacrylate]=100:0.5(□).
DETAILED DESCRIPTION
Embodiments
[0015] The new type of free radical polymerization initiator as described in this invention is peroxide (methyl) acrylate containing a polymerisable double bond, and it is prepared using the methods below:
Method I for Preparing Peroxide (Methyl) Acrylate Containing a Polymerisable Double Bond and Peroxide Bond
[0016] Drop 150 mL of NaOH solution at a mass percentage of 8% into tert-butyl hydroperoxide (17.9992 g, 0.2 mol) dissolved N,N′-dimethylformamide (DMF) (10 mL) added with phenothiazine (0.0193 g, 0.01 mmol), and control the temperature at 0˜15° C. After complete addition of phenothiazine, let it react for 60 min to generate a tert-butyl hydroperoxide solution. Then drop and dissolve it in the methylacryloyl chloride (21.0234 g, 0.2 mol) solution of N,N′-dimethylformamide (DMF) (10 mL) and added with phenothiazine (0.0194 g, 0.01 mmol), control the temperature at 0˜10° C., and let it react for 3 h after completing addition. Then extract it with petroleum ether, and wash it with distilled water until a transparent water phase is obtained, separate the oil phase and add anhydrous Na 2 SO 4 to dry it, and distill it at reduced pressure to obtain the product tert-butyl peroxide methacrylate, with a total yield of 38.43% at a purity of 92.73%. The structural formula of the product is:
[0000]
Method II for Preparing Peroxide (Methyl) Acrylate Containing a Polymerisable Double Bond and Peroxide Bond
[0017] Drop 100 mL of NaOH solution at a mass percentage of 20% into isopropylbenzene hydrogen peroxide (30.0004 g, 0.2 mol) solution dissolved in THF (20 mL) and added with phenothiazine (0.0199 g, 0.2 mmol), and control the temperature at 0˜15° C. After completing addition, let it react for 60 min to generate a sodium isopropylbenzene peroxide solution. Then drop the methylacryloyl chloride (21.0103 g, 0.2 mol) solution dissolved in THF (20 mL) and added with phenothiazine (0.0198 g, 0.01 mmol), control the temperature at 0˜10° C., and let it react for 3 h after completion of addition. Then extract it with petroleum ether, and wash it with distilled water until a transparent water phase is obtained, separate the oil phase and add anhydrous Na 2 SO 4 to dry it, and distill it at reduced pressure to obtain the product isopropylphenyl peroxide methacrylate, with a total yield of 88.21% at a purity of 98.67%. The structural formula of the product is:
[0000]
Method III for Preparing Peroxide (Methyl) Acrylate Containing a Polymerisable Double Bond and Peroxide Bond
[0018] Drop 100 mL of NaOH solution at a mass percentage of 10% into isopropylbenzene hydrogen peroxide (29.9924 g, 0.2 mol) solution dissolved in acetone (20 mL) and added with phenothiazine (0.0198 g, 0.2 mmol), and control the temperature at 0˜15° C. After completedly adding, let it react for 40 min to generate a sodium isopropylbenzene peroxide solution. Then drop the acryloyl chloride (36.1094 g, 0.4 mol) solution dissolved in acetone (20 mL) and added with phenothiazine (0.0195 g, 0.01 mmol), control the temperature at 0˜10° C., and let it react for 3 h after completion of addition. Then extract it with petroleum ether, and wash it with distilled water until a transparent phase is obtained, separate the oil phase and add anhydrous Na 2 SO 4 to dry it, and distill it at reduced pressure to obtain the product isopropylphenyl peroxide acrylate, with a total yield of 79.73% at a purity of 99.02%.
[0019] The structural formula of the product is:
[0000]
Embodiment 1
[0020] Add styrene (St 5.2018 g, 0.05 mol), initiator tert-butyl peroxide methacrylate (0.0396 g, 0.25 mmol) and solvent toluene (1.7325 g) into the reaction flask. They were reacted at 85° C. for 40 h, and the styrene conversion rate was found to be 82.59%. Analyze the polymer with a three-measurement gel permeation chromatograph, and the following result is obtained: light scattering weight-average molecular weight M w.MALLS =418400, gel permeation chromatography weight-average molecular weight M w·GPC =253200, molecular weight distribution PDI=4.72, Mark-Houwink index α=0.455, as shown by the Mark-Houwink curve in FIG. 1 ; average branching factor g′=0.533, which proves that the obtained polymer has branching structure. Refer to FIG. 2 for the variation trend of the branching factor g′ and molecular weight of the branched polymer.
Embodiment 2
[0021] Add styrene (5.2102 g, 0.05 mol), initiator tert-butyl peroxide methacrylate (0.0393 g, 0.25 mmol), and solvent toluene (1.7288 g) into the reaction flask. They were reacted at 60° C. for 40 h, and the styrene conversion rate was found to be 65.31%. Analyze the polymer with a three-measurement gel permeation chromatograph, and the following result is obtained: light scattering weight-average molecular weight M w·MALLS =1284000 g/mol, gel permeation chromatography weight-average molecular weight M w·GPC =460100 g/mol, molecular weight distribution PDI=4.82, Mark-Houwink index α=0.536, average branching factor g′=0.384, which proves that the obtained polymer has branching structure.
Embodiment 3
[0022] Add styrene (5.2099 g, 0.05 mol), initiator isopropylphenyl peroxide methacrylate (0.0527 g, 0.25 mmol), and solvent toluene (1.7348 g) into the reaction flask. They were reacted at 100° C. for 8 h, and the styrene conversion rate was found to be 81.05%. Analyze the polymer with a three-measurement gel permeation chromatograph, and the following result is obtained: light scattering weight-average molecular weight M w·MALLS =782100 g/mol, gel permeation chromatography weight-average molecular weight M w·GPC =433900 g/mol, molecular weight distribution PDI=6.69, Mark-Houwink index α=0.576, as shown by the Mark-Houwink curve in FIG. 1 ; the average branching factor g′=0.658, which proves that the obtained polymer has branching structure. Refer to FIG. 2 for the variation trend of the branching factor g′ and molecular weight of the branched polymer.
Embodiment 4
[0023] Add styrene (5.2131 g, 0.05 mol), initiator isopropylphenyl peroxide methacrylate (0.0516 g, 0.25 mmol), and solvent toluene (1.7318 g) into the reaction flask. They were reacted at 90° C. for 27 h, and the styrene conversion rate was found to be 76.10%. Analyze the polymer with a three-measurement gel permeation chromatograph, and the following result is obtained: light scattering weight-average molecular weight M w·MALLS =888500 g/mol, gel permeation chromatography weight-average molecular weight M w·GPC =356100 g/mol, molecular weight distribution PDI=8.54, Mark-Houwink index α=0.638, average branching factor g′=0.667, which proves that the obtained polymer has branching structure.
Embodiment 5
[0024] Add methyl methacrylate (MMA 5.0036 g, 0.05 mol), initiator tert-butyl peroxide methacrylate (0.0391 g, 0.25 mmol), and solvent xylene (1.0071 g) into the reaction flask. They were reacted at 85° C. for 30 h, and the methyl methacrylate conversion rate was found to be 98.97%. Analyze the polymer with a three-measurement gel permeation chromatograph, and the following result is obtained: light scattering weight-average molecular weight M w·MALLS =68200 g/mol, gel permeation chromatography weight-average molecular weight M W·GPC =40500 g/mol, molecular weight distribution PDI=2.11, Mark-Houwink index α=0.597, average branching factor g′=0.578, which proves that the obtained polymer has branching structure. Refer to FIG. 2 for the variation trend of the branching factor g′ and molecular weight of the branched polymer.
Embodiment 6
[0025] Add vinyl acetate (VAc4.3019 g, 0.05 mol), initiator tert-butyl peroxide methacrylate (0.0393 g, 0.25 mmol), and solvent benzene (1.4268 g) into the reaction flask. They were reacted at 70° C. for 30 h, and the vinyl acetate conversion rate was found to be 88.10%. Analyze the polymer with a three-measurement gel permeation chromatograph, and the following result is obtained: light scattering weight-average molecular weight M w·MALLS =77240 g/mol, gel permeation chromatography weight-average molecular weight M w·GPC =65400 g/mol, molecular weight distribution PDI=1.95, Mark-Houwink index α=0.654, average branching factor g′=0.674, which proves that the obtained polymer has branching structure. Refer to FIG. 2 for the variation trend of the branching factor g′ and molecular weight of the branched polymer.
Embodiment 7
[0026] Add methyl acrylate (MA4.3021 g, 0.05 mol), initiator tert-butyl peroxide methacrylate (0.0791 g, 0.5 mmol), and solvent toluene (1.7331 g) into the reaction flask. They were reacted at 80° C. for 25 h, and the methyl methacrylate conversion rate was found to be 89.37%. Analyze the polymer with a three-measurement gel permeation chromatograph, and the following result is obtained: light scattering weight-average molecular weight M w·MALLS =73700 g/mol, gel permeation chromatography weight-average molecular weight M w·GPC =60600 g/mol, molecular weight distribution PDI=2.77, Mark-Houwink index α=0.659, average branching factor g′=0.702, which proves that the obtained polymer has branching structure. Refer to FIG. 2 for the variation trend of the branching factor g′ and molecular weight of the branched polymer.
Embodiment 8
[0027] Add styrene (5.2172 g, 0.05 mol), initiator tert-butyl peroxide methacrylate (2.3864 g, 0.025 mol), and solvent toluene (7.6342 g) into the reaction flask. They were reacted at 85° C. for 24 h, and the styrene conversion rate was found to be 98.29%. Analyze the polymer with a three-measurement gel permeation chromatograph, and the following result is obtained: light scattering weight-average molecular weight M w·MALLS =23500 g/mol, gel permeation chromatography weight-average molecular weight M w·GPC =19700 g/mol, molecular weight distribution PDI=4.04, Mark-Houwink index α=0.420, average branching factor g′=0.388, which proves that the obtained polymer has branching structure.
Embodiment 9
[0028] Add styrene (5.1970 g, 0.05 mol), initiator isopropylphenyl peroxide methacrylate (5.5045 g, 0.025 mol), and solvent toluene (2.6782 g) into the reaction flask. They were reacted at 80° C. for 21 h, and the styrene conversion rate was found to be 73.80%. Analyze the polymer with a three-measurement gel permeation chromatograph, and the following result is obtained: light scattering weight-average molecular weight M w·MALLS =64500 g/mol, gel permeation chromatography weight-average molecular weight M w·GPC =12900 g/mol, molecular weight distribution PDI=8.37, Mark-Houwink index α=0.588, average branching factor g′=0.570, which proves that the obtained polymer has branching structure.
Embodiment 10
[0029] Add styrene (5.2009 g, 0.05 mol), initiator isopropylphenyl peroxide methacrylate (0.6238 g, 3 mmol), and solvent toluene (2.7373 g) into the reaction flask. They were reacted at 85° C. for 40 h, and the styrene conversion rate was found to be 94.31%. Analyze the polymer with a three-measurement gel permeation chromatograph, and the following result is obtained: light scattering weight-average molecular weight M w·MALLS 32 2675000 g/mol, gel permeation chromatography weight-average molecular weight M w·GPC =280700 g/mol, molecular weight distribution PDI=16.36, Mark-Houwink index α=0.447, average branching factor g′=0.365, which proves that the obtained polymer has branching structure.
Embodiment 11
[0030] Add styrene (5.1919 g, 0.05 mol) and initiator tert-butyl peroxide methacrylate (0.0790 g, 0.5 mmol) into the reaction flask. They were reacted at 80° C. for 36 h, and the styrene conversion rate was found to be 96.1%. Analyze the polymer with a three-measurement gel permeation chromatograph, and the following result is obtained: light scattering weight-average molecular weight M w·MALLS =169000 g/mol, gel permeation chromatography weight-average molecular weight M w·GPC =118500 g/mol, molecular weight distribution PDI=4.57, Mark-Houwink index α=0.574, average branching factor g′=0.770, which proves that the obtained polymer has branching structure.
Embodiment 12
[0031] Add styrene (5.2032 g, 0.05 mol) and initiator isopropylphenyl peroxide methacrylate (1.0406 g, 5 mmol) into the reaction flask. They were reacted at 95° C. for 36 h, and the styrene conversion rate was found to be 97.6%. Analyze the polymer with a three-measurement gel permeation chromatograph, and the following result is obtained: light scattering weight-average molecular weight M w·MALLS =778100 g/mol, gel permeation chromatography weight-average molecular weight M w·GPC =252200 g/mol, molecular weight distribution PDI=22.44, Mark-Houwink index α=0.440, average branching factor g′=0.495, which proves that the obtained polymer has branching structure.
Embodiment 13
[0032] Add styrene (5.1221 g, 0.05 mol) and initiator isopropylphenyl peroxide acrylate (0.1034 g, 0.5 mmol) into the reaction flask. They were reacted at 80° C. for 36 h, and the styrene conversion rate was found to be 91.7%. Analyze the polymer with a three-measurement gel permeation chromatograph, and the following result is obtained: light scattering weight-average molecular weight M w·MALLS =855500 g/mol, gel permeation chromatography weight-average molecular weight M w·GPC =370300 g/mol, molecular weight distribution PDI=8.88, Mark-Houwink index α=0.612, average branching factor g′=0.508, which proves that the obtained polymer has branching structure. | A process for preparing a branched polymer, belonging to the fields of polymer synthesis and preparation of functional polymers. A vinyl monomer, such as styrene, toluene (benzene, xylene) as a solvent, is subjected to a self-initiated free radical polymerization at 60˜100° C. with a new type of compound (methyl (meth)acrylate peroxide) as the initiator and the branched monomer containing both polymerisable double bond and peroxide bond, which can be used to synthesize the branched polymers. The degree of branching of the polymer can be adjusted by adjusting the molar ratio of the new type of compound to polymerisable monomer. The process for preparing a branched polymer is carried out under the conditions of conventional free radical polymerization without the addition of the branched monomer and other assist initiators. The polymerization is simple and feasible, has a high monomer conversion, a controllable degree of branching for the polymer, and is highly suitable for synthesizing branched polymers from various monomers. Another advantage of this process is its low production cost. | 2 |
FIELD OF THE INVENTION
[0001] The present invention is related to a transflective displays using circular polarizers, and more particularly to apparatus, devices, systems, and methods for wide viewing angle and broadband circular polarizers in transflective displays.
BACKGROUND AND PRIOR ART
[0002] Transflective liquid crystal displays, generally rely on circular polarizers to module the light passing through it. Transflective liquid crystal displays are being widely used in various mobile devices due to its high image quality and good sunlight readability. Usually in a transflective LCD (liquid crystal display) device, each pixel is divided into a transmissive (T) region and a reflective (R) region. The R part requires a broadband circular polarizer to reach a good dark state, which requires the T part of LC cell to be sandwiched between two stacked of circular polarizers for a common dark state of the R mode. A broadband circular polarizer is generally required to cover the whole visible spectrum.
[0003] FIG. 1A shows a typical prior art broadband circular polarizer that can be found in many current transflective LCDs that consists of one linear polarizer along with one mono-chromatic half-wave plate and one mono-chromatic quarter-wave plate under a special alignment (S. Pancharatnam, “Achromatic combinations of birefringent plates: part I. An achromatic circular polarizer,” in Proc. Indian Academy of Science, vol. 41, sec. A, 1955, pp. 130-136), and both films are uniaxial positive A plates, that are made of stretched polymer films or homogeneous liquid crystal films. The extraordinary refractive index ne is aligned at the x-y plane, and is larger than their ordinary refractive index no (“Analytical solutions for uniaxial-film-compensated wide-view liquid crystal displays” by X. Zhu et al, Journal of Display Technology, vol. 2, pages 2-20, 2006).
[0004] One drawback of this prior art configuration is the poor viewing angle of the transmissive mode. The off-axis light leakage of such two stacked circular polarizers shown in FIG. 1B is further shown in FIG. 1C , in which the light leakages at different viewing angles (both azimuthal and polar directions) are correspondingly calculated. The calculated results are normalized to their maximum possible output value between two parallel aligned linear polarizers in the normal direction.
[0005] From FIG. 1C , the light leakage of two stacked broadband circular polarizers is severe at off-axis, e.g., the cone with light leakage <10% occurs within 40 degrees, which means the 10:1 contrast ratio of two stacked circular polarizers is limited to around 40 degrees. The poor viewing angle results from the accumulation of the off-axis phase retardation from both positive half-wave and quarter-wave A plates.
[0006] A proposal to overcome the narrow viewing angle for the two stacked circular polarizers is described by Lin et al in “Extraordinary wide-view and high-transmittance vertically aligned liquid crystal displays,” Applied Physics Letter, vol. 90, page 151112 (2007), as shown in FIG. 2 a . Here, a liquid crystal layer such as a vertically aligned cell is sandwiched between two crossed circular polarizers, wherein each circular polarizer consists of a linear polarizer and a mono-chromatic quarter-wave plate, and a thin uniaxial A plate. The mono-chromatic quarter-wave plate has its optic axis set at 45° with respect to the absorption axis of its linear polarizer, and the thin uniaxial A plate has its optic axis perpendicular to the absorption axis of the neighboring linear polarizer. The top and bottom thin A plates are only used to compensate the off-axis light leakage of the two crossed linear polarizers, and are not working as half-wave plate, wherein the retardation of the A plates are much less than a half wavelength and the light passing through the each linear polarizer and its adjoining A plate will not change its polarization state at the normal incidence. By this configuration, the viewing angle can widely expanded to have contrast >10:1 over 80 degrees.
[0007] However, a drawback in this proposal is the narrow band performance for the reflective mode as shown in FIG. 2 b , if this configuration of circular polarizer is employed to be a transflective LCD. The main reasons for this performance comes from the following factors: a). it uses a mono-chromatic quarter-wave plate and a linear polarizer in each circular polarizer, while the two A films between the polarizer and the quarter-wave plate at each side are only used to compensate the light off-axis light leakage of two linear polarizers, and are not working a half-wave plate to expand the bandwidth; and b). for the reflective mode, the light passing through the LC cell twice on the same top side, therefore it views the same typed quarter-wave plate (both positive as in FIG. 2 b ), therefore the quarter-wave plates the reflective light passes cannot compensate each other. FIG. 3 a shows the wavelength dependent light leakage of the configuration in FIG. 2 b.
[0008] From the analysis above, approaches to achieve a new circular polarizer structure for transflective displays with wider viewing angle and broadband properties is highly preferred. Thus, there exists the need for solutions to the problems described by the prior art.
SUMMARY OF THE INVENTION
[0009] A primary objective of the invention is to provide apparatus, devices, systems, and methods for circular polarizers that can have wide viewing angles and are broadband for transflective liquid crystal displays.
[0010] A second objective of the invention is to provide new apparatus, devices, systems, and methods for a transmissive liquid crystal display device that can have wide viewing angles and broadband performance.
[0011] A preferred embodiment of the liquid crystal display device can include a first transparent substrate, a second transparent substrate, a liquid crystal cell having a liquid crystal layer sandwiched between the first and the second transparent substrates, a first circular polarizer disposed behind a viewer's side of the liquid crystal layer; wherein the first polarizer further includes a first linear polarizer, a first half-wave plate, a first quarter-wave plate, a second circular polarizer disposed on the viewer's side of the liquid crystal layer; wherein the second polarizer includes a second linear polarizer, a second half-wave plate, and a second quarter-wave plate, at least one optical retardation compensator disposed between the first circular polarizer and the second circular polarizer, wherein the first half-wave plate and the first quarter-wave plate are positioned between the inner surface of the first linear polarizer and the liquid crystal layer, having the first half-wave plate closer to the first polarizer than the first quarter-wave plate; and the second half-wave plate and the second quarter-wave plate are positioned between the inner surface of the second linear polarizer and the liquid crystal layer, having the second half-wave plate closer to the second polarizer than the second quarter-wave plate, wherein the first half-wave plate and the second half-wave plate are made of uniaxial A plates with opposite optical birefringence; and the first quarter-wave plate and the second quarter-wave plate are made of uniaxial A plates with opposite optical birefringence, a switch applied to the liquid crystal layer for switching the phase retardation of the liquid crystal layer between a zero and a half-wave plate value for attaining different gray levels.
[0012] The first linear polarizer and the second linear polarizer can include dichroic polymer films that have transmission axis perpendicular to each other. The dichroic polymer films can be a polyvinyl-alcohol-based film.
[0013] The first half-wave plate in the first circular polarizer that is away from the viewer can include a positive uniaxial A plate, the first quarter-wave plate includes a negative uniaxial A plate, the second half-wave plate includes a negative uniaxial A plate, and the second quarter-wave plate includes a positive uniaxial A plate. The positive and negative uniaxial A plates can have at least one of a polymer layer or a homogenous liquid crystal film.
[0014] The first half-wave plate in the first circular polarizer that is away from the viewer can include a negative uniaxial A plate, the first quarter-wave plate includes a positive uniaxial A plate; the second half-wave plate includes a positive uniaxial A plate and the second quarter-wave plate includes of negative uniaxial A plate. The positive and negative uniaxial A plates can have at least one of a polymer layer or a homogenous liquid crystal film.
[0015] The optic axis of the second half-wave plate can be set at an angle from −30° to −5° with respect to the transmission axis of the second linear polarizer, that is closer to the viewer; the second quarter-wave plate has its optic axis set at from approximately −15° to approximately +35° with respect to the transmission axis of the second linear polarizer, correspondingly; the first half-wave plate has its optic axis angle set at an angle from approximately −30° to approximately −5° with respect to the transmission axis of the second linear polarizer; and the first quarter-wave plate has its optic axis angle at an angle from approximately −15° to approximately +35° with respect to the transmission axis of the second linear polarizer, with respect to the transmission axis of the second linear polarizer.
[0016] The optic axis of the second half-wave plate can be set at an angle from approximately −30° to approximately −5° with respect to the transmission axis of the second linear polarizer, that is closer to the viewer; the second quarter-wave plate has its optic axis set at from approximately −15° to approximately +35° with respect to the transmission axis of the second linear polarizer, correspondingly; the first half-wave plate has its optic axis angle set at an angle from approximately −30° to approximately −5° with respect to the transmission axis of the second linear polarizer; and the first quarter-wave plate has its optic axis angle at an angle from approximately −15° to approximately +35° with respect to the transmission axis of the second linear polarizer, with respect to the transmission axis of the second linear polarizer.
[0017] The optic axis of the half-wave plate can be set at an angle from approximately +5° to approximately +30° with respect to the transmission axis of the second linear polarizer that is closer to the viewer, the second quarter-wave plate has its optic axis set at from approximately −35° to approximately +15° with respect to the transmission axis of the second linear polarizer, correspondingly, the first half-wave plate has its optic axis angle at an angle from approximately +5° to approximately +30° with respect to the transmission axis of the second linear polarizer, and the first quarter-wave plate has its optic axis angle set at an angle from approximately −35° to approximately +15° with respect to the transmission axis of the second linear polarizer, with respect to the transmission axis of the second linear polarizer.
[0018] The optic axis of the half-wave plate can be set at an angle from approximately +5° to approximately +30° with respect to the transmission axis of the second linear polarizer that is closer to the viewer, the second quarter-wave plate has its optic axis set at from approximately −35° to approximately +15° with respect to the transmission axis of the second linear polarizer, correspondingly, the first half-wave plate has its optic axis angle at an angle from approximately +5° to approximately +30° with respect to the transmission axis of the second linear polarizer, and the first quarter-wave plate has its optic axis angle set at an angle from approximately −35° to approximately +15° with respect to the transmission axis of the second linear polarizer, with respect to the transmission axis of the second linear polarizer.
[0019] The first half-wave plate can include a positive uniaxial A plate, the first quarter-wave plate includes a positive uniaxial A plate, the second half-wave plate includes a negative uniaxial A plate, and the second quarter-wave plate includes a negative uniaxial A plate. The positive and negative uniaxial A plates can have at least one of a polymer layer or a homogenous liquid crystal film.
[0020] The first half-wave plate can include a negative uniaxial A plate, the first quarter-wave plate includes a negative uniaxial A plate; the second half-wave plate includes a positive uniaxial A plate and the second quarter-wave plate includes a positive uniaxial A plate. The positive and negative uniaxial A plate can have at least one of a polymer layer or a homogenous liquid crystal film.
[0021] The optic axis of the second half-wave plate can be set at an angle from approximately −30° to approximately −5° with respect to the transmission axis of the second linear polarizer that is closer to the viewer, the second quarter-wave plate has its optic axis set at from approximately −15° to approximately +35° with respect to the transmission axis of the first linear polarizer that is away from the viewer correspondingly, the first half-wave plate has its optic axis angle set at an angle from approximately −30° to approximately −5° with respect to the transmission axis of the second linear polarizer, and the first quarter-wave plate has its optic axis angle at an angle from approximately −15° to approximately +35° with respect to the transmission axis of the first linear polarizer, with respect to the transmission axis of the second linear polarizer.
[0022] The optic axis of the second half-wave plate can be set at an angle from approximately −30° to approximately −5° with respect to the transmission axis of the second linear polarizer that is closer to the viewer, the second quarter-wave plate has its optic axis set at from approximately −15° to approximately +35° with respect to the transmission axis of the first linear polarizer that is away from the viewer correspondingly, the first half-wave plate has its optic axis angle set at an angle from approximately −30° to approximately −5° with respect to the transmission axis of the second linear polarizer, and the first quarter-wave plate has its optic axis angle at an angle from approximately −15° to approximately +35° with respect to the transmission axis of the first linear polarizer, with respect to the transmission axis of the second linear polarizer.
[0023] The optic axis of the second half-wave plate can be set at an angle from approximately +5° to approximately +30° with respect to the transmission axis of the second linear polarizer that is closer to the viewer, the second quarter-wave plate has its optic axis set at from approximately −35° to approximately +15° with respect to the transmission axis of the first linear polarizer that is away from the viewer correspondingly, the first half-wave plate has its optic axis angle set at an angle from approximately +5° to approximately +30° with respect to the transmission axis of the second linear polarizer, and the first quarter-wave plate has its optic axis angle set at an angle from approximately −35° to approximately +15° with respect to the transmission axis of the first linear polarizer, with respect to the transmission axis of the second linear polarizer.
[0024] The optic axis of the second half-wave plate can be set at an angle from approximately +5° to approximately +30° with respect to the transmission axis of the second linear polarizer that is closer to the viewer, the second quarter-wave plate has its optic axis set at from approximately −35° to approximately +15° with respect to the transmission axis of the first linear polarizer that is away from the viewer correspondingly, the first half-wave plate has its optic axis angle set at an angle from approximately +5° to approximately +30° with respect to the transmission axis of the second linear polarizer, and the first quarter-wave plate has its optic axis angle set at an angle from approximately −35° to approximately +15° with respect to the transmission axis of the first linear polarizer, with respect to the transmission axis of the second linear polarizer. The at least one optical retardation compensator can be laminated between the liquid crystal layer and one of the first and second circular polarizers.
[0025] The optical retardation compensator can include a negative C film having a total phase retardation value (dΔn) between approximately −400 nm to approximately −250 nm.
[0026] The liquid crystal cell can be a transmissive liquid crystal cell. The liquid crystal layer can be selected from a group consisting of: a vertically aligned cell, electrically controlled birefringence cell, and an optically compensated birefringence cell.
[0027] The liquid crystal cell can be a transflective liquid crystal display. The transflective display can include a first transparent substrate, a second transparent substrate, a liquid crystal cell, a first circular polarizer, wherein the first polarizer further includes a first linear polarizer, a first half-wave plate, a first quarter-wave plate, a second circular polarizer, wherein the second polarizer includes a second linear polarizer, a second half-wave plate, and a second quarter-wave plate; and the second circular polarizer located closer to the front side of the display than the first circular polarizer, and pixel circuits between the first and second substrates, each of the pixel circuits having a transmissive portion and a reflective portion, wherein the reflective portion includes a reflector for reflecting the external light, and the transmissive portion includes a transmitter to modulate light generated by an internal light source.
[0028] The transflective display can include a first transparent substrate, a second transparent substrate, a first circular polarizer, wherein the first polarizer further comprises of a first linear polarizer, a first half-wave plate, a first quarter-wave plate, a second circular polarizer, wherein the second polarizer comprises of a second linear polarizer, a second half-wave plate, and a second quarter-wave plate, the second circular polarizer can be located closer to the front side of the display than the first circular polarizer, and a liquid crystal layer, in which a portion of the liquid crystal layer is used to modulate light when the display is operating in a transmissive mode, and the same portion of the liquid crystal layer is used to modulate light when the display is operating in a reflective mode, and
[0029] The first half-wave plate and the first quarter-wave plate can be positioned between the inner surface of the first linear polarizer and the liquid crystal layer having the first half-wave plate closer to the first linear polarizer, and the second half-wave plate and the second quarter-wave plate are positioned between the inner surface of the second linear polarizer and the liquid crystal layer having the second half-wave plate closer to the second linear polarizer, and the first half-wave plate and the second half-wave plate are made of uniaxial A plates and are configured with opposite optical birefringence, and the first quarter-wave plate and the second quarter-wave plate are made of uniaxial A plates and are configured with opposite optical birefringence.
[0030] The first half-wave plate and the first quarter-wave plate can be positioned between the inner surface of the first linear polarizer and the liquid crystal layer having the first half-wave plate closer to the first linear polarizer, and the second half-wave plate and the second quarter-wave plate are positioned between the inner surface of the second linear polarizer and the liquid crystal layer having the second half-wave plate closer to the second linear polarizer, and the first half-wave plate and the second half-wave plate are made of uniaxial A plates and are configured with opposite optical birefringence, and the first quarter-wave plate and the second quarter-wave plate are made of uniaxial A plates and are configured with opposite optical birefringence.
[0031] Further objects and advantages of this invention will be apparent from the following detailed description of preferred embodiments which are illustrated schematically in the accompanying drawings.
BRIEF DESCRIPTION OF THE FIGURES
[0032] FIG. 1A is the structure of a conventional prior art broadband circular polarizer.
[0033] FIG. 1B is a diagram of two stacked conventional circular polarizers of FIG. 1A .
[0034] FIG. 1C is the angular dependent light leakage of two stacked conventional circular polarizers.
[0035] FIG. 2A is a prior art view of wide viewing circular polarizers for transmissive mode.
[0036] FIG. 2B shows the configuration of a reflective display device using the circular polarizer in FIG. 2A .
[0037] FIG. 2C shows the wavelength dependent light leakage for a reflective device using the circular polarizer in FIG. 2A .
[0038] FIG. 3A shows the structure of the first embodiment of the invention.
[0039] FIG. 3B is the optic axis alignment for each layer in the first embodiment of FIG. 3A .
[0040] FIG. 4A is polarization trace on the Poincaré sphere for each broadband circular polarizer.
[0041] FIG. 4B shows a mechanism for dark state on the Poincaré sphere.
[0042] FIG. 4C shows a mechanism for bright state on the Poincaré sphere.
[0043] FIG. 5A shows the wavelength dependent transmissive light leakage of the first embodiment with
[0000]
ϕ
+
1
2
λ
=
approximately
75
°
and
ϕ
-
1
4
λ
=
approximately
-
75
°
,
and
ϕ
-
1
2
λ
=
approximately
75
°
and
ϕ
+
1
4
λ
=
approximately
-
75
°
.
[0044] FIG. 5B shows the wavelength dependent reflective light leakage of the first embodiment with
[0000]
ϕ
-
1
2
λ
=
approximately
75
°
and
ϕ
+
1
4
λ
=
approximately
-
75
°
.
[0045] FIG. 6 shows the wavelength dependent transmissive light leakage of the first embodiment with
[0000]
ϕ
+
1
2
λ
=
approximately
73
°
and
ϕ
+
1
4
λ
=
approximately
-
79
°
,
and
ϕ
-
1
2
λ
=
approximately
77
°
and
ϕ
+
1
4
λ
=
approximately
-
71
°
.
[0046] FIG. 7A shows the angular dependent light leakage of two stacked broadband circular polarizers with
[0000]
ϕ
+
1
2
λ
=
approximately
75
°
and
ϕ
-
1
4
λ
=
approximately
-
75
°
,
and
ϕ
-
1
2
λ
=
approximately
75
°
and
ϕ
+
1
4
λ
=
approximately
-
75
°
.
[0047] FIG. 7B shows the angular dependent light leakage of two stacked broadband circular polarizers with
[0000]
ϕ
+
1
2
λ
=
approximately
73
°
and
ϕ
-
1
4
λ
=
approximately
-
79
°
,
and
ϕ
-
1
2
λ
=
approximately
77
°
and
ϕ
-
1
4
λ
=
approximately
-
71
°
.
[0048] FIG. 8 shows the iso-contrast plot for the configuration in the first embodiment.
[0049] FIG. 9A shows the structure of a second embodiment of the invention.
[0050] FIG. 9B shows the optic axis alignment for each layer in the second embodiment of FIG. 9B .
[0051] FIG. 10 shows the off-axis light leakage of two stacked broadband circular polarizer of the second embodiment.
[0052] FIG. 11 shows the iso-contrast plot for the configuration in the second embodiment.
[0053] FIG. 12A shows the structure of the third embodiment of the invention.
[0054] FIG. 12B shows the optic axis alignment for each layer in the third embodiment.
[0055] FIG. 13A shows a polarization trace on the Poincaré sphere for each broadband circular polarizer.
[0056] FIG. 13B shows a mechanism for dark state on the Poincaré sphere.
[0057] FIG. 13C shows a mechanism for bright state on the Poincaré sphere.
[0058] FIG. 14A shows the wavelength dependent transmissive light leakage of the third embodiment with
[0000]
ϕ
+
1
2
λ
=
approximately
75
°
,
ϕ
+
1
4
λ
=
approximately
15°
,
ϕ
-
1
2
λ
=
approximately
75
°
and
ϕ
-
1
4
λ
=
approximately
15°
.
[0059] FIG. 14B shows the wavelength dependent reflective light leakage of the third embodiment with
[0000]
ϕ
+
1
2
λ
=
approximately
75
°
,
ϕ
+
1
4
λ
=
approximately
15°
,
ϕ
-
1
2
λ
=
approximately
75
°
and
ϕ
-
1
4
λ
=
approximately
15°
.
[0060] FIG. 15 shows the wavelength dependent transmissive light leakage of the third embodiment with
[0000]
ϕ
+
1
2
λ
=
approximately
78
°
,
ϕ
+
1
4
λ
=
approximately
21
°
,
ϕ
-
1
4
λ
=
approximately
13
°
and
ϕ
-
1
2
λ
=
approximately
74
°
.
[0061] FIG. 16A shows the off-axis light leakage of two stacked broadband circular polarizer of the third embodiment with
[0000]
ϕ
+
1
2
λ
=
approximately
75
°
,
ϕ
+
1
4
λ
=
approximately
15
°
,
ϕ
-
1
2
λ
=
approximately
75
°
and
ϕ
-
1
4
λ
=
approximately
15
°
.
[0062] FIG. 16B shows the off-axis light leakage of two stacked broadband circular polarizer of the third embodiment with
[0000]
ϕ
+
1
2
λ
=
approximately
78
°
,
ϕ
+
1
4
λ
=
approximately
21
°
,
ϕ
-
1
4
λ
=
approximately
13
°
and
ϕ
-
1
2
λ
=
approximately
74
°
.
[0063] FIG. 17 shows the iso-contrast plot for the configuration in the fourth embodiment of the invention.
[0064] FIG. 18A shows the structure of a fourth embodiment of the invention.
[0065] FIG. 18B shows the optic axis alignment for each layer in the fourth embodiment.
[0066] FIG. 19 shows the off-axis light leakage of two stacked broadband circular polarizer of the fourth embodiment.
[0067] FIG. 20 shows the iso-contrast plot for the configuration in the fourth embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0068] Before explaining the disclosed embodiments of the present invention in detail it is to be understood that the invention is not limited in its application to the details of the particular arrangements shown since the invention is capable of other embodiments. Also, the terminology used herein is for the purpose of description and not of limitation.
Embodiment 1
[0069] FIG. 3A is cross-sectional diagram of a first embodiment of the wide-view and broadband circular polarizer configuration in a transflective typed LCD or for the pure T typed LCD. A liquid crystal layer 150 , such as a vertically aligned LC cell, is sandwiched between a first glass substrate 155 a and a second glass substrate 155 b , wherein a thin-film-transistor (TFT) array such as those shown and described in U.S. Pat. Nos. 5,528,055 to Komori; 6,424,396 to Kim et al.; and 6,760,087, each of which are incorporated by reference. A TFT transistor array can be formed on the bottom substrate 155 a to provide driving voltages to modulate the liquid crystal layer therebetween.
[0070] The liquid crystal layer along with the two glass substrates are further interposed between two stacked broadband circular polarizers 130 a and 130 b , wherein these two circular polarizers compensate with each other to reduce the off-axis light leakage. The first circular polarizer 130 a consists of a first linear polarizer 100 a , a first half-wave plate 110 a , and a first quarter-wave plate 120 a , wherein the half-wave plate 110 a is laminated between the polarizer 100 a and the quarter-wave plate 120 a . The first half-wave plate 110 a is made of a positive uniaxial A plate (e.g., stretched polymer film or homogeneous liquid crystal film), wherein its extraordinary refractive index ne is aligned at the x-y plane and is larger than its ordinary refractive index no. The first quarter-wave plate 120 a is made of a negative uniaxial A plate, with its extraordinary refractive index ne aligned at the x-y plane and is smaller than its ordinary refractive index no.
[0071] On the other side of the liquid crystal layer 150 , a second linear polarizer 1001 , a second half-wave plate 110 b made of negative uniaxial A plate, and a second quarter-wave plate 120 b made of positive uniaxial A plate form the second circular polarizer 130 b . At least one retardation film 152 such as a negative C plate is laminated between the liquid crystal layer 150 and the top and bottom circular polarizers, respectively.
[0072] The alignment of optic axis for each layer is illustrated in FIG. 3B , wherein the transmission axis 101 a of the linear polarizer 100 a is set as the x-axis. The first half-wave plate 110 a has its optic axis 111 a set at an angle
[0000]
ϕ
+
1
2
λ
[0000] with respect to the transmission axis 101 a of the linear polarizer 100 a . The quarter-wave plate 120 a has its optic axis 121 a set at an angle
[0000]
ϕ
-
1
4
λ
[0000] with respect to the transmission axis 101 a of the linear polarizer 100 a . The transmission axis 101 b of the second linear polarizer 100 b is perpendicular to the transmission axis 101 a of the first linear polarizer. The optic axis 111 b of the half-wave plate 110 b is set at an angle
[0000]
ϕ
-
1
2
λ
[0000] with respect to the transmission axis 101 a of the first linear polarizer 100 a . And the optic axis of 121 b the quarter-wave plate 120 b has an angle
[0000]
ϕ
+
1
4
λ
[0000] with respect to the transmission axis 101 a of the first linear polarizer 100 a.
[0073] Because the wave plates are all made of uniaxial A plates wherein their extraordinary axes are all aligned in the x-y plane, an alignment with optic axis angle at φ is equivalent to the one with optic axis aligned at φ±π in the same x-y plane, e.g., one A film with φ=approximately 80° is same as the A film with its azimuthal angle with φ=approximately −100°. As a result, to uniquely define an alignment direction of one A plate, the angle can be defined in the range of (−π/2 , π/2] to represent all the possible alignment values.
[0074] To work as a wide-view and broadband circular polarizers for a transflective LCD, the alignment angles of these A films need to satisfy, certain relations. Generally, three requirements need to be satisfied:
[0075] 1.) the angle of the top half-wave plate that is closer to the viewer needs to be around approximately ±15° away from the transmission axis of the top linear polarizer, as to make the reflective mode a broadband mode;
[0076] 2.) in each circular polarizer, the azimuthal angles of the half-wave plate and quarter-wave plate needs to satisfy certain relations to make each a broadband circular polarizer; and
[0077] 3.) the corresponding half-wave plates (or quarter-wave plates) needs to be aligned closely parallel to each other, to compensate the off-axis light leakage. Detailed explanations will be illustrated in the examples followed.
[0078] For the structure in FIG. 3B to work as a broadband circular polarizer, the alignment angle of each uniaxial A plate in each circular polarizer ( 130 a and 130 b ) needs to satisfy special relations. First, the angle
[0000]
ϕ
-
1
2
λ
[0000] of the top half-wave plate is set at approximately 75° with respect to the transmission axis of the bottom circular polarizer, which is also approximately −15° away from the top polarizer's transmission direction 101 b . Therefore, the bottom half-wave plate also needs to set its angle
[0000]
ϕ
+
1
2
λ
[0000] at approximately 75° from abovementioned requirements.
[0079] FIG. 4A shows the change of the polarization states traced on a Poincaré sphere (where the equator represents linear polarizations, and the poles stand for circular polarizations with different handiness) for a light passing through these two stacked circular polarizers at a normal incidence. Point T depicts the transmission axis 101 a of the polarizer 100 a on the Poincaré sphere, which also represents the polarization state of the incident light passing through the bottom linear polarizer 100 a . As the top and bottom polarizers are crossed to each other, the transmission axis of the top polarizer is represented by the point A on the Poincaré sphere, where ∠AOT=2×90°=approximately 180°.
[0080] Because the optic axis of the first half-wave plate 110 a is at
[0000]
ϕ
+
1
2
λ
[0000] to the transmission axis 101 a in FIG. 3B , the point H representing its optic axis 111 a of the half-wave plate 110 a on the Poincaré sphere has an angle of
[0000]
2
ϕ
+
1
2
λ
[0000] with respect to the axis OT, i.e.,
[0000]
∠
HOT
=
2
ϕ
+
1
2
λ
=
2
×
75
°
=
approximately
150
°
.
[0000] Similarly the point Q representing optic axis 121 a of the quarter-wave plate 120 a on the Poincaré sphere has an angle of
[0000]
2
ϕ
-
1
4
λ
[0000] with respect to the axis OT, i.e.,
[0000]
∠
QOT
=
2
ϕ
+
1
4
λ
.
[0081] Under such a configuration, the light passing through the linear polarizer 100 a will first have a polarization state at point T (linear polarization); then it will be rotated half a circle on the Poincaré sphere surface (equal to λ/2 change on the Poincaré sphere) along the axis OH to the point C by the half-wave plate 110 a , where the light still keeps a linear polarization state and the angle
[0000]
∠
COT
=
4
ϕ
+
1
2
λ
=
approximately
300
°
.
[0000] In order to transfer the light to a circular polarization (to move polarization state from point C to point D), the axis OQ for the quarter-wave plate needs to be perpendicular to the OC axis, i.e, ∠QOT=approximately ± 90 °, or the following relation
[0000]
2
ϕ
-
1
4
λ
-
4
ϕ
+
1
2
λ
=
±
π
2
[0000] needs to be satisfied.
[0082] In order to make this single circular polarizer broadband, the trace of polarization change should be kept in the same top or bottom half sphere. Therefore, for the case with a positive A plate for half-wave plate and a negative A plate for the quarter-wave plate with
[0000]
ϕ
+
1
2
λ
=
approximately
75
°
,
[0000] the relation should be
[0000]
2
ϕ
-
1
4
λ
-
4
ϕ
+
1
2
λ
=
-
π
2
,
i
.
e
.
,
ϕ
-
1
4
λ
=
approximately
-
75
°
.
[0000] Similarly, the optic angles of the top half-wave plate 120 b and the top quarter-wave plate 110 b needs to satisfy
[0000]
2
ϕ
-
1
4
λ
-
4
ϕ
-
1
2
λ
=
-
π
2
,
where
ϕ
-
1
2
λ
=
approximately
75
°
.
[0000] More generally, the angle between their optic axes should be
[0000]
2
ϕ
1
2
λ
-
4
ϕ
1
2
λ
=
-
π
2
+
2
m
π
,
[0000] here m is an integer that can be 0 or ±1, and each φ is in the range of (−π/2 , π/2], here m is equal to −1.
[0083] FIG. 4B shows the dark state mechanism from the Poincaré sphere for the transmissive part. The optic axis of the half-wave plate 110 b can be represented by the point I with
[0000]
∠
IOT
=
2
ϕ
-
1
2
λ
=
approximately
150
°
,
[0000] and the optic axis of the quarter-wave plate 120 b can be represented by the point R with
[0000]
∠
ROT
=
2
ϕ
+
1
4
λ
=
approximately
-
150
°
[0000] or approximately 210°. Under such a configuration, the light passing through the bottom circular polarizer 130 a will have a first circular polarization state as point D in FIG. 4A . If the LC layer 150 introduces no phase retardation for the light at normal direction, it will keep its polarization after the LC layer. Because the optic axis of the half-wave plate and the top quarter-wave plate satisfying
[0000]
2
ϕ
+
1
4
λ
-
4
ϕ
1
2
λ
=
-
π
2
+
2
m
π
,
[0000] as shown in FIG. 4B , the circularly polarized light will move from point D to E by the quarter-wave plate 120 b and then from E to T by the half-wave plate 110 b.
[0084] Because the absorption axis 101 b of the top linear polarizer 100 b is parallel to the transmission axis 101 a of the bottom polarizer 100 a , the light will be blocked and absorbed by the top linear polarizer 100 b . Thus a dark state can be achieved. For the reflective mode, similar analysis can be applied and a common dark state can be obtained as the transmissive mode.
[0085] On the other hand, if the liquid crystal layer is driven by certain voltage from the TFT arrays on the glass substrate to behave like a have-wave plate, a bright state can be achieved. Under this case, the light passing the bottom circular polarizer will be a circularly polarized light, which is represented by the point D on the north pole of the Poincaré sphere. The liquid crystal will change its handiness from the north pole D to the south pole F by its half-wavelength like phase retardation. Then the quarter-wave plate 120 b will move the light from point F to point G, which is a point opposite to the point E through axis EO. Finally the half-wave plate 110 b moves the light from point G to point A, where the point A is the transmission axis position of the top polarizer 100 b . As a result, a bright state can be achieved.
[0086] FIG. 5A shows the transmissive light leakage at the dark state of the abovementioned configurations in FIG. 3B in the visible spectrum from λ/approximately 380 nm to λ=approximately 780 nm. The extraordinary and ordinary refractive index ne and no of the positive A plates are set as no=approximately 1.5866 and ne=approximately 1.5902, and those for the negative A plates are set as no=approximately 1.60 and ne=approximately 1.50 at λ=approximately 589 nm. And the centered wavelength is set at approximately 550 nm. Their optic axis alignments are as the followings:
[0000]
ϕ
+
1
2
λ
=
75
°
,
ϕ
-
1
4
λ
=
-
75
°
,
ϕ
-
1
2
λ
=
75
°
and
ϕ
+
1
4
λ
=
-
75
°
.
[0087] It can be seen from the figure that this polarizer is quite broadband with light leakage less than approximately 0.5% in the whole visible spectrum. FIG. 5B shows the reflective light leakage at the dark state using only top circular polarizer 130 b and a reflector. As we can see, the transmittance still keeps a broadband property with leakage less than approximately 0.5% from approximately 450 nm to approximately 700 nm, and the reflectance is less than approximately 2% in the same spectrum, which makes it suitable for both T and R modes in a transflective LCD.
[0088] Besides, the configuration here also shows a wide-view property, as shown in FIG. 5A , where the wavelength dependent light leakage for the transmissive mode at an incident polar angle of approximately 80° is almost same to that in the normal direction, while the conventional even produces a large leakage at angle of approximately 40°. The off-axis wavelength dependent light leakage of the reflective mode of this example is also better than that of the conventional one, as indicated in FIG. 5B .
[0089] The optic axis angles of the bottom and top complementary retardation plates are not necessarily equal and set exactly at approximately 75°. FIG. 6 shows the wavelength dependent light leakage with
[0000]
ϕ
-
1
2
λ
=
approximately
73
°
and
ϕ
-
1
4
λ
=
approximately
-
79
°
,
and
ϕ
-
1
2
λ
=
approximately
77
°
and
ϕ
+
1
4
λ
=
approximately
-
71
°
.
[0000] Throughout the whole approximately 450 nm to approximately 700 nm spectrum, the light leakage is less than approximately 0.1% for T mode, and approximately 6% for the R mode. Here in FIG. 6 , the phase retardation of the liquid crystal layer and the C film is also included.
[0090] With complementary optical refractive index between the two half-wave plates and the two quarter-wave plates, respectively, the off-axis light leakage can be greatly suppressed. FIG. 7A shows the light leakage of the configurations, where
[0000]
ϕ
+
1
2
λ
=
approximately
75
°
,
ϕ
-
1
4
=
approximately
-
75
°
,
ϕ
-
1
2
λ
=
approximately
75
°
,
and
ϕ
+
1
4
λ
=
approximately
-
75
°
.
[0000] It shows expand the light leakage >approximately 1% over approximately 40°, which is much better than the configurations using all positive A plates.
[0091] Considering a liquid crystal layer having its molecules substantially perpendicular to the substrate at its dark state, such as a normally black mode VA cell sandwiched between above-configured circular polarizers, additional negative C film 152 (where their extraordinary refractive index ne aligned at the z axis and its ne is smaller than the ordinary refractive index no) can be added to the two sides of the VA cell to mainly compensate the off-axis phase retardation from the LC part, as shown in FIG. 3A .
[0092] The calculated iso-contrast plot of the current example is shown in FIG. 8 . In the calculation, the LC cell is set at approximately 4 μm, using a negative dielectric anisotropic liquid crystal material MLC-6608, available from Merck, Germany that has a parallel dielectric constant ∈ ∥ =approximately 3.6, a perpendicular dielectric constant ∈ ⊥ =approximately 7.8, elastic constants K 11 =approximately 16.7 pN, K 33 =approximately 18.1 pN, an extraordinary refractive index ne=approximately 1.5578, and an ordinary refractive index no=approximately 1.4748 at wavelength λ=approximately 589 nm. The negative C films are have their extraordinary refractive index ne=approximately 1.49288 and ordinary refractive index no=approximately 1.50281.
[0093] The phase retardation value dΔn of the C film is set at approximately −360 nm. The optic axis angles of the half-wave and quarter-wave plate are
[0000]
ϕ
+
1
2
λ
=
approximately
73
°
and
ϕ
-
1
4
λ
=
approximately
-
79
°
,
and
ϕ
-
1
2
λ
=
approximately
77
°
and
ϕ
+
1
4
λ
=
approximately
-
71
°
.
[0094] FIG. 7B shows the angular light leakage of the above alignment angles and retardation films, the off-axis light leakage is greatly suppressed to less than approximately 0.015, which is improved from that in FIG. 7A . The iso-contrast ratio plot is shown in FIG. 8 , where the contrast ratio approximately 10 to 1 is expanded to over entire viewing cone, which is much greatly improved as compared to the case using all positive A plates.
[0095] On the other hand, the azimuthal angle of the top half-wave plate can also be aligned at approximately −75° with respect to the transmission axis 101 a of the bottom linear polarizer, which is also approximately +15° to the transmission axis 101 b . Therefore a broad bandwidth for the reflective mode can also be guaranteed. In this case, with the assistance of Poincaré sphere, the angles of the half-wave plate and quarter-wave need to satisfy
[0000]
2
ϕ
1
4
λ
-
4
ϕ
1
2
λ
=
+
π
2
+
2
m
π
,
[0000] where m is an integer that can be 0 or ±1. For example
[0000]
ϕ
+
1
2
λ
=
approximately
-
75
°
,
ϕ
-
1
4
λ
=
approximately
75
°
,
ϕ
-
1
2
λ
=
approximately
-
75
°
and
ϕ
+
1
4
λ
=
approximately
75
°
,
[0000] where m=approximately +1.
[0096] Here the LCD device can also be a pure transmissive typed LCD. And the liquid crystal layer is not confined to a normally black initially vertically aligned cell, it can also use a normally white ECB cell (electrically controlled birefringence) or an OCB cell (optically compensated birefringence) where the LC molecules are substantially vertically aligned at high voltages that are much larger than the threshold voltage of the material. Besides, additional compensation films for the LC cell not illustrated here can be added without departing from the spirit of the present invention, and should not be considered as a limitation of this invention.
Embodiment 2
[0097] In a second embodiment of the present invention as shown in FIG. 9A , the birefringence of each A plate is just set opposite in correspondence to the configuration in FIG. 3A , wherein the LC cell 250 is sandwiched between a first glass substrate 255 a and a second glass substrate 255 b , wherein a thin-film-transistor (TFT) array (not shown here) is formed on the bottom substrate 255 a to provide driving voltages to modulate the liquid crystal layer therebetween. The liquid crystal layer along with the two glass substrates are further interposed between two circular polarizers 230 a and 230 b . The first circular polarizer 230 a further comprises of a first linear polarizer 200 a , a first half-wave plate 210 a , and a first quarter-wave plate 220 a . The second circular polarizer 230 b further comprises of a second linear polarizer 200 b , a second half-wave plate 210 b , and a second quarter-wave plate 220 b . Their optic axis is shown in FIG. 9B .
[0098] As described in abovementioned Embodiment 1, when the birefringence of the half-wave and quarter-wave A plate within each circular polarizer is opposite (e.g. a positive A plate for one wave plate and a negative A plate the other one), the angle between their optic axes should be
[0000]
2
ϕ
1
4
λ
-
4
ϕ
1
2
λ
=
±
π
2
+
2
m
π
,
[0000] here m is an integer that can be 0 or ±1, and each φ is in the range of (−π/2, π/2]. Here if
[0000]
ϕ
1
2
λ
=
approximately
75
°
,
then
2
ϕ
1
4
λ
-
4
ϕ
1
2
λ
=
-
π
2
+
2
m
π
[0000] should be satisfied, e.g.,
[0000]
ϕ
-
1
2
λ
=
approximately
+
75
°
,
ϕ
+
1
4
λ
=
approximately
-
75
°
,
ϕ
-
1
4
λ
=
approximately
-
75
°
,
ϕ
+
1
2
λ
=
approximately
+
75
°
,
and
m
=
-
1.
[0000] And on the other hand, if
[0000]
ϕ
1
2
λ
=
approximately
-
75
°
,
then
2
ϕ
1
4
λ
-
4
ϕ
1
2
λ
=
+
π
2
+
2
m
π
[0000] should be satisfied, e.g.,
[0000]
ϕ
-
1
2
λ
=
approximately
-
75
°
,
ϕ
+
1
4
λ
=
approximately
+
75
°
,
ϕ
-
1
4
λ
=
approximately
+
75
°
,
ϕ
+
1
2
λ
=
approximately
-
75
°
,
and
m
=
+
1.
[0099] FIG. 10 shows the light leakage where
[0000]
ϕ
-
1
2
λ
=
approximately
+
75
°
and
ϕ
+
1
4
λ
=
approximately
-
75
°
[0000] in the bottom polarizer,
[0000]
ϕ
+
1
2
λ
=
approximately
+
75
°
and
ϕ
-
1
4
λ
=
approximately
-
75
°
[0000] in the top circular polarizer. In this case the reflective ambient light will first see a positive half-wave plate then a negative quarter-wave plate, as different from the example in the first embodiment. Similarly the light leakage at off-axis is greatly reduced to have a viewing cone with light leakage greater than approximately 1% over approximately 40°.
[0100] The viewing angle plot is shown in FIG. 11 with
[0000]
ϕ
-
1
2
λ
=
approximately
+
73
°
,
ϕ
+
1
4
λ
=
approximately
-
79
°
,
ϕ
-
1
4
λ
=
approximately
-
75
°
,
ϕ
+
1
2
λ
=
approximately
+
75
°
[0000] and dΔn of the C film is set at approximately −270 nm, where contrast ratio >10:1 is over 80° at most directions. Similarly, the half-wave plate can also have an angle close to
[0000]
ϕ
1
2
λ
=
approximately
-
75
°
[0000] and the quarter-wave plate could be
[0000]
ϕ
1
4
λ
=
approximately
75
°
to
satisfy
2
ϕ
1
4
λ
-
4
ϕ
1
2
λ
=
+
π
2
+
2
m
π
.
Embodiment 3
[0101] Yet in anther embodiment of the wide-view and broadband circular polarizer structure for a transflective typed LCD in FIG. 12A , the half-wave plate and the quarter-wave plate within each circular polarizer are of the same type (e.g., both are positive A plates, or both are negative plates), but corresponding half-wave plate or quarter-wave plate in different circular polarizers are of the opposite type. In FIG. 12A , a first linear polarizer 300 a along with a first half-wave plate 310 a and a first quarter-wave plate 320 a forms the first broadband and wide-viewing angle circular polarizer 330 a . Here both half-wave and quarter-wave plates in the first circular polarizer are made of positive A plates, wherein the transmission axis 301 a of the linear polarizer 300 a is set along the x-axis and the optic axes of the wave plates 310 a and 320 a are set at
[0000]
ϕ
+
1
2
λ
and
ϕ
+
1
4
λ
.
[0102] On the other side a second linear polarizer 300 b along with a second half-wave plate 310 b and a second quarter-wave plate 320 b forms the second broadband and wide-viewing angle circular polarizer 330 b . And both half-wave and quarter-wave plates are made of negative A plates, wherein the transmission axis 301 b of the linear polarizer 300 b is set perpendicular to that of the first linear polarizer 300 a and the optic axes of the wave plates 310 b and 320 b are set at
[0000]
ϕ
-
1
2
λ
and
ϕ
-
1
4
λ
.
[0000] A liquid crystal 350 interposed between two TFT glass substrates 355 a and 355 b is sandwiched between the circular polarizers to switch between the dark state and bright state. Corresponding optic axis alignment is illustrated in FIG. 12B .
[0103] FIG. 13A shows the required optic axis alignment for same type films within each circular polarizer through the Poincaré sphere. Similarly, the angle φ 1/2λ of the top half-wave plate is set at approximately 75° with respect to the transmission axis of the bottom circular polarizer, which is also −15° away from the top polarizer's transmission direction 301 b . Then the angle of the bottom half-wave plate is also set at that value. Therefore, for example, the transmission axis of the bottom polarizer 300 a can be represented by the point T′ on the Poincaré sphere and the optic axis of the half-wave plate 310 a can be characterized by the point H′, which as an angle of
[0000]
2
ϕ
+
1
2
λ
[0000] to the OT′ axis
[0000]
(
∠
H
’
OT
’
=
2
ϕ
+
1
2
λ
=
approximately
150
°
)
,
[0000] and the optic axis of the quarter-wave plate 320 a is represented by the point Q′ that has an angle
[0000]
∠
Q
’
OT
’
=
2
ϕ
+
1
4
λ
[0000] to the OT′ axis.
[0104] The light passing the polarizer 300 a will have a polarization state of T′, then the half-wave plate will move it to the point C′, which is also a linear polarization with an angle
[0000]
∠
C
’
OT
’
=
4
ϕ
+
1
2
λ
=
approximately
300
°
[0000] or approximately −60°. Then the quarter-wave plate 320 a will rotate the linear polarization C′ to the pole D′.
[0105] Here in order to make the traces all above or below the same half-sphere, it requires
[0000]
2
ϕ
+
1
4
λ
-
4
ϕ
+
1
2
λ
=
+
π
2
+
m
π
,
[0000] where m can be equal to 0, ±1. Similarly for the top circular polarizer, it requires
[0000]
2
ϕ
-
1
4
λ
-
4
ϕ
-
1
2
λ
=
+
π
2
+
m
π
[0000] to achieve broadband property. Therefore, we can determine the angle values as follows:
[0000]
ϕ
+
1
2
λ
=
approximately
75
°
and
ϕ
+
1
4
λ
=
approximately
15
°
,
and
ϕ
-
1
2
λ
=
approximatel
75
°
and
ϕ
-
1
4
λ
=
approximately
15
°
,
and
m
=
+
1.
[0106] FIG. 13B illustrates the mechanism of the dark state when the liquid crystal layer 350 contributes no phase retardation in the normal incidence. The light passing through the bottom circular polarizer 330 a will have a circular polarization at D′ on the Poincaré sphere. Then it will be rotated back to the point E′ as a linear polarization by the quarter-wave plate 320 b made of a negative A plate, and be further moved to the point T′ by the negative half-wave A plate. Consequently, it will be blocked by the top polarizer 300 b , where its transmission axis 301 b is perpendicular to the transmission axis 301 a of the bottom linear polarizer 300 a.
[0107] If the liquid crystal is turned to be equivalent to a half-wave plate for the transmissive portion, the cell will appear bright as indicated by FIG. 13C . The light passing the bottom circular polarizer 330 a will have circular polarization state at D′ first, then it will be changed in handiness by the liquid crystal layer to the point F′. After passing the quarter-wave plate 320 b , the polarization will be further moved to point G′ and be further moved to A′ by the half-wave plate 310 b , where A′ is the point representing the transmission axis 301 b of the top linear polarizer 300 b on the Poincaré sphere. Therefore a bright state can be achieved.
[0108] FIG. 14A shows the wavelength dependent light leakage of the present embodiment, where
[0000]
ϕ
+
1
2
λ
=
approximately
75
°
and
ϕ
+
1
4
λ
=
approximately
15
°
,
and
ϕ
-
1
2
λ
=
approximately
75
°
and
ϕ
-
1
4
λ
=
approximately
15
°
.
[0000] As we can see over the visible range, the light leakage of the T part is less than 0.5% in the normal direction.
[0109] FIG. 14B shows the corresponding light leakage with circular polarizer 330 b in the reflective configuration. Broadband property still keeps. In addition, their optic angles can also be set at different values such as
[0000]
ϕ
+
1
2
λ
=
approximately
78
°
and
ϕ
+
1
4
λ
=
approximately
21
°
,
and
ϕ
-
1
4
λ
=
approximately
13
°
and
ϕ
-
1
2
λ
=
approximately
74
°
.
[0000] Still the light leakage at all visible lights are all less than 1% for the T mode and less than 8% for the R mode between approximately 450 nm and approximately 700 nm as shown in FIG. 15 . And the reflectance at the dark state also remains a broadband property.
[0110] The off-axis light leakage with
[0000]
ϕ
+
1
2
λ
=
approximately
75
°
and
ϕ
+
1
4
λ
=
approximately
15
°
,
and
ϕ
-
1
2
λ
=
approximately
75
°
and
ϕ
-
1
4
λ
=
approximately
15
°
[0000] is illustrated in FIG. 16A , where the light leakage is well suppressed to have light leakage less than 1% in a cone with a polar angle over approximately 40° at all azimuthal directions. In other words, under such a configuration, the two circular polarizers are truly broadband and wide-viewing angle, as the off-axis light leakage is well reduced.
[0111] Similarly, considering a liquid crystal layer having its molecules substantially perpendicular to the substrate at its dark state, one additional negative C film with retardation value dΔn=approximately −362.5 nm can be applied to compensate the phase retardation from the LC cell itself and the off-axis light leakage from the two linear polarizers.
[0112] FIG. 16B shows the light leakage of the embodiment with a negative C plate included and with
[0000]
ϕ
+
1
2
λ
=
approximately
78
°
and
ϕ
+
1
4
λ
=.
approximately
21
°
,
and
ϕ
-
1
4
λ
=.
approximately
13
°
and
ϕ
-
1
2
λ
=.
approximately
74
°
.
[0000] The off-axis light leakage is greatly suppressed than those in FIG. 16A . Besides, as indicated in FIG. 17 , the viewing cone with contrast ratio >approximately 10 to 1 is expanded to over. approximately 80° at most directions.
[0113] Similarly, the liquid crystal layer is not confined to a normally black LC cell with an initial vertical alignment, it can also use a normally white ECB cell (electrically controlled birefringence) or an OCB cell (optically compensated birefringence) where the LC molecules are substantially vertically aligned at high voltages that are much larger than the threshold voltage of the material.
[0114] On the other hand, the azimuthal angle of the top half-wave plate can also be aligned at approximately −75° with respect to the transmission axis 301 a of the bottom linear polarizer, which is also approximately +15° to the transmission axis 301 b . Therefore a broad bandwidth for the reflective mode can also be guaranteed. In this case, with the assistance of Poincaré sphere, the angles of the half-wave plate and quarter-wave need to satisfy
[0000]
2
ϕ
1
4
λ
-
4
ϕ
1
2
λ
=
-
π
2
+
2
m
π
,
[0000] where m is an integer that can be 0 or ±1. For example,
[0000]
ϕ
+
1
2
λ
=
approximately
-
75
°
,
ϕ
+
1
4
λ
=
approximately
-
15
°
,
ϕ
-
1
2
λ
=
approximately
-
75
°
and
ϕ
-
1
4
λ
=
approximately
-
15
°
,
where
m
=
+
1.
Embodiment 4
[0115] In a fourth embodiment, where the two uniaxial half-wave and quarter-wave plates in top circular polarizer are both made of positive uniaxial A films, and the other two in the bottom circular polarizer are made of negative uniaxial A films. As shown in FIG. 18A , the LC cell 450 is sandwiched between two circular polarizers 430 a and 430 b . The first circular polarizer 430 a further comprises of a first linear polarizer 400 a , a first half-wave plate 410 a , and a first quarter-wave plate 420 a . The second circular polarizer 430 b further comprises of a second linear polarizer 400 b , a second half-wave plate 410 b , and a second quarter-wave plate 420 b . Their optic axis is shown in FIG. 18B .
[0116] Because the birefringence of each A plate within each circular polarizer is same (e.g., a positive A plate for one wave plate and a positive A plate the other one), when
[0000]
ϕ
-
1
2
λ
=
approximately
+
75
°
,
[0000] the angle between their optic axes should be
[0000]
2
ϕ
1
4
λ
-
4
ϕ
1
2
λ
=
+
π
2
+
2
m
π
,
[0000] here m is an integer that can be 0 or ±1, and each φ is in the range of (−π/2, π/2].
[0117] FIG. 19 shows the light leakage where
[0000]
ϕ
-
1
2
λ
=
approximately
+
75
°
and
ϕ
-
1
4
λ
=
approximately
+
15
°
[0000] in the bottom polarizer,
[0000]
ϕ
+
1
2
λ
=
approximately
+
75
°
and
ϕ
+
1
4
λ
=
approximately
+
15
°
[0000] in the top circular polarizer. In this case the reflective ambient light will first see both a positive half-wave plate and a positive quarter-wave plate, as different from the example in the third embodiment.
[0118] Similarly the light leakage at off-axis is greatly reduced to have a viewing cone with light leakage greater than approximately 1% over approximately 40°. The viewing angle plot including a LC layer is shown in FIG. 20 , where contrast ratio >approximately 10 to approximately 1 is over approximately 80° at most directions. Similarly, the half-wave plate can also have an angle close to
[0000]
ϕ
1
2
λ
=
-
75
°
[0000] and the quarter-wave plate could be
[0000]
ϕ
1
4
λ
=
approximately
-
15
°
to
satisfy
2
ϕ
1
4
λ
-
4
ϕ
1
2
λ
=
-
π
2
+
2
m
π
.
[0119] In summary, the structures of the present invention attain wide viewing angle and broadband circular polarizers, which are quite promising for wide viewing angle, full color transflective and transmissive LCDs.
[0120] White the invention has been described, disclosed, illustrated and shown in various terms of certain embodiments or modifications which it has presumed in practice, the scope of the invention is not intended to be, nor should it be deemed to be, limited thereby and such other modifications or embodiments as may be suggested by the teachings herein are particularly reserved especially as they fall within the breadth and scope of the claims here appended. | Apparatus, devices, systems, and methods for wide viewing angle and broadband circular polarizers in transflective displays. A liquid crystal display configuration can include two stacked circular polarizers, each having a linear polarizer, a half-wave plate and a quarter-wave plate wherein two linear polarizers are crossed to each other, two half-wave plates are made of uniaxial A plates with opposite optical birefringence (one positive and one negative type), and two quarter-wave plates are made of uniaxial A plates with opposite optical birefringence (one positive and one negative type). The configurations can generate wide viewing angles and broadband properties and are suitable for display applications that require circular polarizers. | 6 |
TECHNICAL FIELD
[0001] The invention is concerned with a method for sending a batch download of messages in a telecommunication network.
BACKGROUND ART
[0002] The Global System for Mobile Communication (GSM) is a standard for digital wireless communications. GSM has different services, such as voice telephony. The Subscriber Identity Module (SIM) inside GSM phones was originally designed as a secure way to connect individual subscribers to the network but is nowadays becoming a standardized and secure application platform for GSM and next generation networks.
[0003] In the GSM system, Mobile Station (MS) represents the only equipment the GSM user ever sees from the whole system. It actually consists of two distinct entities. The actual hardware is the Mobile Equipment (ME), which consists of the physical equipment, such as the radio transceiver, display and digital signal processors. The subscriber information is stored in the Subscriber Identity Module (SIM), implemented as a Smart Card.
[0004] In addition to voice telephony, today's second-generation GSM networks deliver high quality and secure mobile voice and data services (such as SMS/Text Messaging) with full roaming capabilities across the world.
[0005] In mobile networks people can be contacted by calling to their mobile telephone number or by sending to that number a so called short message by e.g. making use of the Short Message Service (SMS). Short Message Service (SMS) is the transmission of short text messages to and from a mobile phone, fax machine and/or IP address. SMS messages must be no longer than 160 alphanumeric characters and contain no images or graphics. The point-to-point Short message service (SMS) provides a means of sending messages of limited size to and from GSM mobiles. Detailed information can be found in the ETSI standard GSM 03.40 Version 5.3.0.
[0006] The basic network structure of the SMS service comprises two entities, which may receive or send messages being the endpoints between which the SMS message is sent. The entity can be located in a fixed network, a mobile station or an internet protocol network.
[0007] Messages to and from mobile stations are received by a Short Message Service Center (SMSC), which then directs it to appropriate mobile device if the message is to be sent to a mobile station or it must generally direct it to a recipient.
[0008] There are many cases where an operator wants to download certain data to all its subscribers, such as different service downloads and Public Land Mobile Network (PLMN) updates. Examples of such updates are amending of the service center number when sending SMS messages, change of a PLMN to influence on the roaming, change of service provider name, settings for WAP or e-mail, telephone list updates and sending advertisements through SMS. The downloading is handled in batches where data is targeted to a certain group of cards in the form of large Over-the-Air (OTA) downloads of data to (U)SIM cards.
[0009] GSM has no broadcasting capability for broadcasting data, but must rely on a batch of single casts, where each receiver must be targeted individually, which sets great demand on the delivery system in terms of capacity and throughput.
[0010] When an operator wants to make a batch download, data will be sent to each receiver, which will create large queues in all intermediate parts of the network, such as in e.g. SMS-C, since such download messages usually have to be divided in several successive messages. The OTA downloads delivered to the customers might be quite large, ranging from 5 up to 30 SMs per subscriber, if a batch targets 100,000 subscribers. If e.g. a quarter of these are inactive, the number of queued SMs will be somewhere between 125,000 and 750,000 which will quite seriously affect the performance for other traffic. If the receiver is inactive the queues will be full for some time, degrading the performance until the payload is expired or the receiver is turned on.
THE OBJECT OF THE INVENTION
[0011] The object of the invention is to decrease the large queues in the intermediate entities when sending a batch download of messages.
SUMMARY OF THE INVENTION
[0012] The method of the invention for sending a batch download message in a telecommunication network comprising a sender entity, one or more receiver entities, and intermediate entities there between, is mainly characterized by creating a test message and sending the test message to each receiver, receiving an acknowledgement in case of a successful delivery of the test message sent, creating the real message to be sent to said receiver(s) and submitting the real message in batches.
[0013] The preferable embodiments of the invention have the characteristics of the sub claims.
[0014] The test message is either a part of the batch download message, whereby the test message and the real message together form the batch download message or the test message and the real message are separate messages.
[0015] All messages are sent via the intermediate entities, in some of which the test message is queued if the receiver is not listening. If the test message was not successfully submitted to the receiver and it was queued in an intermediate entity, an error message is sent by the intermediate entity in question to the service provider. The real message will not be sent until a successful test message sending takes place, why the content provider has to resend a test message in order to complete the process.
[0016] The telecommunication network is e.g. the GSM network, whereby one intermediate entity is the Short Message Service Centre (SMS-C) and the receiver is a SIM card in a mobile station. Another example of a telecommunication network is the UMTS network and the receiver is a USIM card in a mobile station.
[0017] As was presented in the prior art section, operators might need to download data in batches to mobile receivers, since one SMS message, with which the data is sent can only contain 160 characters. A lot of data will therefore be sent to each receiver, which in the prior art methods create large queues in all intermediate parts of the network, such as in e.g. SMS-C or in some intermediate entity in the service provider.
[0018] With the invention, only one message, i.e. the test message, will be sent to check that the receiver is active. While this may get queued due to an inactive receiver, the queue depth needed will be decreased as most of the payload consisting of several messages will not be sent in the first hand. The test message may have a different validity period (e.g. it can be very short in order to expire the messages quickly) than the rest of the download to further reduce the queues.
[0019] The invention will enhance the download performance by lessen the load on the network components in connection with the service provider and other network components such as the SMS-C. As only one Short Message (SM) will be sent to each subscriber before it is sure that they are listening the queues will be smaller. When the subscriber is listening for sure, the full payload will get delivered promptly.
[0020] Not only will the invention decrease the queues, but the creating of messages that never will never be delivered are also avoided, since this will take some load off from the functions in the service provider, who creates the specific short messages and from functions performing service management.
[0021] In the following, the invention will be described by means of some examples by referring to figures. The intention is not to restrict the invention to the details of the following presentation.
FIGURES
[0022] FIG. 1 is a view of an example of a network environment wherein the invention can be applied
[0023] FIG. 2 is a signal diagram of an embodiment of the method of the invention in the case of successful delivery of the test message
[0024] FIG. 3 is a flow diagram of the method of the invention it its whole
DETAILED DESCRIPTION
[0025] FIG. 1 is a view of an example of a network environment wherein the invention can be applied.
[0026] The intention is to submit a batch download message from a sender entity. The batch download message consists of several parts, and can be a batch update to be sent to the (U)SIM card of one or more mobile stations in e.g. a GSM network or UMTS. The downloading is handled in batches where data is targeted to a certain group of cards in the form of large Over-the-Air (OTA) downloads of data to (U)SIM cards.
[0027] The downloading form the sender entity may be originated from e.g. a service provider marked with reference number 1 in FIG. 1 .
[0028] The managing of the downloading is product specific and depends on the vendor's solution. Usually, an application of the service provider performs the downloads, which are sent via some component that is responsible for creating correctly formatted short messages from the incoming requests from the application. This component might also handle chaining if possible and applies the correct security depending on card type. In some component of the service provider, applications may be stored for execution for later downloading. Also different formats of short messages are preferably managed. Finally, the management operations might include queuing of messages if more than one is intended for the same subscriber in order not to overflow the Short Message Service Center (SMSC).
[0029] The Short Message Service Centre (SMS-C) marked with reference number 2 in FIG. 1 dispatches the short messages to their destination. It will queue messages if the subscriber is not available and send it when the subscriber comes online again.
[0030] The GSM network itself is marked with reference number 3 in FIG. 1 .
[0031] The messages are sent to the SIM card 5 of mobile stations (MS) 4 (only one shown in FIG. 1 ).
[0032] The basic idea of the invention is to make sure that the receiver is turned on and listening before sending the whole payload, since if the receiver is not listening, the payload, which might consist of several messages, is queued by SMS-C thereby causing traffic stocks. Therefore only a first short message command (SM) is sent first in the invention and waiting for a successful delivery is performed before sending the rest of the message. If the first command is not delivered successfully (i.e. expired or an error message is received) the rest of the payload is not sent.
[0033] FIG. 2 is a signal diagram of an embodiment of the method of the invention, wherein a successful delivery of the test message takes place. The example embodiment of FIG. 2 assumes that the telecommunication network, in which the method takes place is the GSM network.
[0034] The whole process might start with a request from a client for downloading data, or the operator makes take the initiative. If the data to be sent might only have the size of one short message, i.e. not more than 160 characters. In that case, all data is sent immediately. The invention applies to case, wherein the data to be sent has to be divided in several messages.
[0035] In FIG. 2 , the service provider is creating a test message in step 1 of FIG. 2 after having noted that the data to be sent is more than one message. This test message can be an alert message separate from the real message to be sent later or it can be a part of the batch download message, such as the first batch of the total message.
[0036] Advantageously, the test message is a PING command. PING is short for Packet InterNet Groper and it is used to verify if a network data packet is capable of being distributed to an address without errors. The ping utility is commonly used to check for network errors. Basically, Ping is an Internet program for verifying that a particular IP address exists and can accept requests. The verb ping means the act of using the ping utility or command. Ping is used diagnostically to ensure that a host computer you are trying to reach is actually operating. If, for example, a user can't ping a host, then the user will be unable to use the File Transfer Protocol (FTP) to send files to that host. If there is an error in the delivery to the destination, the ping command displays an error message.
[0037] Ping can also refer to the Acknowledgement Code (ACK). This is done before sending e-mail in order to confirm that all of the addresses are reachable.
[0038] In creating the test message, the invention advantageously makes use of the PING command technology.
[0039] The test message is then sent to the SIM card of a mobile station via the SMS-C as signals 2 and 3 . If successful delivery of the message is informed to the service provider by the mobile station via the SMS-C as signals 4 and 5 , the real message is now created by the service provider as step 6 of FIG. 2 . The real message is then submitted in batches to the SIM card of the mobile phone via the SMS-C in signals 7 and 8 . Signals 7 and 8 illustrates here all the successive signals, which can be several or only these two, needed to send the real messages in batches.
[0040] FIG. 3 is a flow diagram of the method of the invention it its whole. Also here it is assumed that the telecommunication network is the GSM network.
[0041] In FIG. 3 , the service provider creates the test message, e.g. a ping command, in step 1 . The test message is then sent to the SIM card of a mobile station via possible intermediate entities and the SMS-C. Some functions of these intermediate entities are explained in connection with FIG. 1 . They are in connection with this figure called intermediate entity I collectively. In step 2 , the test message is received by intermediate entity I. Some of these intermediate entities included in intermediate entity I preferably checks the status of the mobile station the test message is intended to be sent to, with respect to telephone number, status etc.
[0042] If according to the checked status, the telephone number used is not working or something else is wrong in, which is checked in step 3 , an error message is sent to the service provider in step 4 . But if no hinder exists, and the receiver status is ok according to step 3 , the test message is forwarded by the intermediate entity I to intermediate entity II in step 5 , which is the SMS-C, for example when it is question about the GSM network. Intermediate entity II then starts sending of the test message to the SIM card of the mobile station in step 6 . If the receiver is not listening, the intermediate entity II sends an error message, like that in step 4 , to the service provider, which has to start the whole process over again. If the receiver is listening, then it receives the test message and sends a confirmation message to the service provider in step 8 . The service provider then creates the real message and sends it to the receiver's SIM card in batches in step 9 .
[0043] As was stated earlier, the test message can be an alert message separate from the real message to be sent later or it can be a part of the batch download message, such as the first batch of the total message. When the test message is a PING command, there is no need to create a special ping request; also in that case it could be the first part of the large download. If it is a part of the larger download no time is wasted to do extra short messages or the ping. | The method of the invention for sending a message batch download in a telecommunication network comprising a sender entity, one or more receiver entities, and intermediate entities there between, is mainly characterized by creating a test message and sending the test message to each receiver, receiving an acknowledgement in case of a successful delivery of the test message sent, creating the real message to be sent to said receiver(s) and submitting the real message in batches. | 7 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an apparatus and a method for the low-contamination melting of a substance in general and in particular for the melting of high-purity, aggressive and/or high-melting glass or glass-ceramic, specifically.
2. Description of Related Art
In traditional melting methods, glass is melted continuously in a platinum crucible or in refractory tank furnaces. A drawback of such methods is that some of the platinum is released to the melt, and the refractory tank furnaces have only short service lives. The desired high-purity glass quality cannot be achieved in this case.
There are also known methods in which glass is melted continuously in melting tank furnaces and removed. To obtain high-quality glass, a refining channel and a homogenization device or tank furnace may follow the melting tank furnace.
In both the above mentioned methods, discontinuous or continuous, the melting crucible or the melting tank furnace are externally heated, e.g. by a burner, and the heat is conductively transmitted to the melt in the interior. There is direct contact between the melt and the crucible or tank furnace. This has a number of drawbacks.
Firstly, the maximum melt temperature is limited by the crucible or tank furnace material. Therefore, the melting crucible or melting tank furnace and if appropriate the refining channel and the homogenization tank furnace usually consist of platinum, which has a relatively high melting point and is relatively resistant to corrosion.
Furthermore, the platinum melting crucible or the platinum melting tank furnace, and also the refining channel and the homogenization tank furnace, is attacked and corroded by the glass melt.
In any case, platinum disadvantageously leads to contaminations or impurities in the glass, which have an adverse effect on the optical properties, in particular the transmission, and consequently these conductive-heating methods can only be used to a very restricted extent for high-purity glasses. Impurities of this nature lead to transmission losses in optical fiber transmission systems of up to 200 to 500 dB/km.
This has proven extremely problematical in particular for the melting of aggressive glasses, e.g. zinc silicate or lanthanum borate glasses, since these glasses cause extensive corrosion to the crucibles or tank furnaces.
In addition to the conductive-heating methods mentioned above, it is also known to use methods in which glass is melted and heated inductively in a skull crucible.
A skull crucible typically comprises meandering water-cooled metal tubes which are spaced apart from one another. The melt inside the interior of the skull crucible is heated by a coil arrangement arranged around the skull crucible by high-frequency power being introduced into the melt.
Cooling of the skull crucible results in the formation of a substantially solid layer or crust of material of the same composition, i.e. in particular of glass, between the skull crucible and the melt. To this extent, impurities in the melt caused by the crucible material are significantly reduced.
A skull crucible is known, for example, from PETROV YU. B. et al., “Continuous Casting Glass Melting in a Cold Crucible Induction Furnace”, XV. International Congress on Glass 1989, Proceedings, Vol. 3a, 1989, pages 72 to 77.
However, the complex structure, in particular the high-frequency technology requirements of an inductively heated skull melting device, results in completely new requirements and problems compared to the abovementioned conductive-heating melting apparatuses. Firstly, the high melting temperature and very high throughtput rates per crucible volume means that many solution approaches for conductive-heating apparatuses cannot readily be transferred to skull melting apparatuses.
In principle, high melting rates and therefore high throughputs can be achieved with a skull melting apparatus. Although this is desirable, on the other hand this may under certain circumstances cause the quality of the melt and therefore of the end product to suffer, for example as a result of thermal reduction. This also leads to a deterioration in the transmission properties of the glass.
Furthermore, the rate at which the high-frequency radiation is introduced depends on various parameters of the melt. Therefore, the melting performance is restricted not only by the high-frequency power emitted by the coil arrangement but also by the melting parameters and crucible geometries.
Consequently, the known skull melting apparatuses are in need of improvement in particular with regard to the quality and homogeneity of the melt and also with regard to the melting capacity or throughput.
Document DE 199 39 780 A1 has disclosed an induction-heated skull crucible in which the metal tubes of the crucible wall are short-circuited with one another above the base, in order to displace the HF field upward or downward.
Document DE 199 39 779 A1 describes an apparatus for the continuous melting and refining of glasses and glass-ceramics, which comprises a melting vessel, a refining vessel and an agitation crucible. The agitation crucible is located at the end of a channel which is connected to the refining vessel.
Document DE 199 39 785 A1 has disclosed a method and an apparatus for producing colored glasses in which, during the further processing, the melt is fed through a skull device. This skull device is located downstream of a melting station.
Document WO 98/05185 A1 shows an induction furnace for glass melting, having a cooled tongue and an induction device beneath the tongue.
U.S. Pat. No. 3,244,494 has disclosed a method for introducing and melting in a glass furnace which is induction-heated. The result is a convective flow, but the flow rate of this convective flow is slow enough to ensure that raw material cannot or can scarcely descend into the melted glass.
The abovementioned apparatuses and methods can be improved further in terms of the melting capacity and glass quality.
WO 00/32525 has disclosed a method and an apparatus for vitrifying organic waste, in particular radioactive waste, in which the supply of oxygen used to oxidize the organic substances is effected both from the surface and from the underside of a melting crucible. Oxygen is supplied substantially in such a way that it has a locally limited influence. As a result, however, the redox state of the melt is only locally changed and the melt as a whole is not homogenized.
SUMMARY OF THE INVENTION
Therefore, it is an object of the present invention to provide an apparatus and a method, in particular a skull melting apparatus or a skull melting method, for melting a substance, in particular glass or glass-ceramic, which allow an improved homogeneity, an increased melting capacity, an increased throughput and/or a high substance or glass quality to be achieved.
A further object of the present invention is to further develop known skull melting apparatuses or skull melting methods and to avoid or at least alleviate the drawbacks of known apparatuses and methods.
The object of the invention is achieved in a surprisingly simple way by the subject matter of the claims.
The apparatus according to the invention, in particular a skull melting apparatus for melting or fusing a substance or compound, in particular for melting high-purity, aggressive and/or high-melting glass or glass-ceramic, comprises a, preferably coolable, e.g. water-cooled crucible or skull crucible and an emitting device for emitting electromagnetic radiation, in particular a coil arrangement arranged around the crucible. The emitting device or coil arrangement emits in particular high-frequency electromagnetic radiation which is introduced into a melt inside the crucible, so that the melt is heated by means of the absorbed high-frequency power. Furthermore, there is a mixing or homogenization device for mixing or homogenizing the melt, the mixing or homogenization device being assigned to the crucible, for example being arranged on and/or in the crucible, so that the mixing or homogenization can take place in the crucible or melting crucible.
It is preferable for batch which is to be melted to be laid onto the melt continuously, approximately in the center and from above, and for liquid melt to be removed from the crucible continuously.
The inventors have established that simply the fact of mixing and/or homogenizing the melt in the melting crucible or skull crucible makes it possible to achieve surprising multiple benefits. Firstly, unmelted batch which drops into the melt in solid form, for example from above, is melted more quickly as a result of more intimate mixing with the liquid fraction of the melt. Surprisingly, the inventors have discovered that the effective contact area between the melt and the supplied material is greatly increased and therefore the melting capacity rises. Secondly, the temperature distribution of the melt is made more even. Thirdly, a uniform distribution of mixing of different glass constituents which, for example, may have different melting points and/or high-frequency coupling coefficients, is achieved. Fourthly, the redox state of the glass can be adjusted.
The action mechanisms which have been discovered are of relevance in particular in conjunction with the inductive high-frequency heating which is preferably used, since the coupling or introduction of the electromagnetic radiation is also dependent on the state of aggregation, the temperature and the particular glass constituent in the melt. In particular, the coupling to unmelted batch constituents is very low.
The apparatus according to the invention and the method are also particularly suitable for high-melting glasses which require melting temperatures of at least 1500° C. or 1600° C. Furthermore, aggressive glasses, e.g. zinc silicate glasses or lanthanum borate glasses, can be melted successfully.
The mixing or homogenization is preferably carried out without any contamination or at least with little contamination, which is highly advantageous in particular for high-purity glasses.
To be mixed or homogenized, it is preferable for the melt to be set in internal motion deliberately or in a predetermined way, or for internal motion to be induced, boosted and/or maintained. In particular, a predefined flow, e.g. with a predefined flow velocity and/or flow direction, is induced in the melt. By way of example, by targeted generation of a temperature difference it is possible to cause a convective flow in the melt, or to induce, assist or boost an existing convective flow.
The mixing or homogenization can be induced or generated with or without material being introduced into the melt.
A preferred form of the material-introducing mixing comprises the introduction of batch which is formed in such a manner that, for example, a flow is induced in the melt simply as a result of the batch being introduced. For this purpose, by way of example, a pelletized and/or coated batch in which in particular gas bubbles are enclosed and/or which releases gas bubbles when it melts is used. It is also possible for the batch to be supplied in pelletized, coated and/or other compacted form without these gas bubbles. In the context of the present invention, the term pelletizing is to be understood as meaning combination to form a stable, solid body, for example by means of pressing. The term coating is to be understood as meaning a structure similar to a solid provided, for example, with a vitreous covering. This, in a particularly advantageous way, both avoids dusting resulting from granular and fine-granular material being supplied and, furthermore, significantly improves the filling rate, since a significantly increased amount of material can be introduced into the melt for the same volumetric flow. Furthermore, batch constituents can be substituted by more fine-grained material without increased dusting occurring, the fine-grained material leading to an optimized melting rate as a result of shortened diffusion paths.
As an alternative or in addition, it is preferable for a batch which has been formed, for example into rods and effects mixing or homogenization in particular by being rotated as it is lowered into the melt, is added. The rods, which are, for example, in the shape of propellers, in particular define an agitator which dissolves of its own accord.
As an alternative or in addition, it is also possible to provide an external agitation device, in particular made from coated metal, for mechanical agitation, or an agitator which is immersed into the melt and dissolves of its own accord, for example by melting, and is made from the same material as the melt.
A particularly preferred embodiment of the invention comprises a device for introducing gas or gas bubbles, for example by means of one or more gas nozzles, into the melt. The gas nozzle is preferably cooled, in particular liquid-cooled, e.g. water-cooled, and is preferably arranged at the base of the crucible. The cooling of the gas nozzle may be connected to the cooling of the crucible or may be formed separately.
According to a particularly preferred embodiment, the gas nozzle projects through the base of the crucible, at least in sections, and extends into the interior of the crucible. In particular, a tip of the gas nozzle extends as far as or into the melt, so that gas which emerges from the gas nozzle or tip rises into the melt in the form of gas bubbles. This bubbling effect intimately mixes and homogenizes the melt in the melting crucible in a particularly simple way.
It is preferable to use O 2 -containing gas, which has proven highly advantageous in particular for lead silicate glasses. This is because in these glasses the lead is thermally reduced at high melt temperatures, which are used for a high melting capacity. This in turn has an adverse effect on the transmission of the glass, in a similar way to platinum contamination, and may even lead to expensive discoloration, making the melted glass completely unusable. Introduction of oxygen into the melt to prevent the lead from being reduced, so that effective control of the redox state of the glass is achieved by the introduction of gas. This even makes it possible, for example, for lead silicate glass to achieve a melting capacity of approximately 500 kg/day, 800 kg/day, 1000 kg/day or more and, at the same time, to avoid or at least alleviate a significant deterioration in the transmission qualities.
It is preferable for the section of the nozzle which projects into the melt, i.e. for example the tip, to be made from low-contamination material, e.g. a light metal, in particular aluminum, magnesium or beryllium, or at least to be coated with a material of this type. Coating with polytetrafluoroethylene (Teflon®) also appears possible.
In order, after the gas nozzle has “frozen up”, i.e. after a solid layer of substance or glass has formed over the gas nozzle, for the gas nozzle to be opened up or cleared again, it is preferable for the gas nozzle to comprise a device for punching through a solid substance or skull layer. This punching device is in particular produced as a needle, e.g. from a material which is able to withstand high temperatures, such as tungsten or similar metal. It is preferable for the needle to be arranged in the center of the gas nozzle, preferably in a longitudinally displaceable manner.
In the text which follows, the invention is explained in more detail on the basis of preferred exemplary embodiments and with reference to the figures, in which identical reference symbols denote identical or similar components.
BRIEF DESCRIPTION OF THE FIGURES
In the drawing:
FIG. 1 shows a diagrammatic sectional illustration of a first embodiment of the apparatus according to the invention with a gas nozzle;
FIG. 2 shows a diagrammatic plan view from above of part of the crucible base in accordance with the first embodiment of the invention,
FIG. 3 shows a diagrammatic sectional illustration of part of the crucible base on section line A-A in FIG. 2 ,
FIG. 4 shows a diagrammatic sectional illustration of an upper part of the gas nozzle in accordance with the first embodiment of the invention,
FIG. 5 shows a longitudinal section through the gas nozzle in accordance with the first embodiment of the invention,
FIG. 6 shows a cross section through the gas nozzle on section line B-B in FIG. 5 ,
FIG. 7 shows a diagrammatic sectional illustration of a second embodiment of the invention,
FIG. 8 shows a diagrammatic sectional illustration of a third embodiment of the invention,
FIG. 9 shows a diagrammatic sectional illustration of a fourth embodiment of the invention,
FIG. 10 shows a diagrammatic, perspective illustration of an agitator which dissolves of its own accord, in accordance with a fifth embodiment of the invention, and
FIG. 11 shows a diagrammatic sectional illustration of the first embodiment of the invention, having a refining channel and a homogenization tank furnace.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a first embodiment of the apparatus 1 according to the invention for melting glass, having a cooled, e.g. water-cooled, crucible or melting crucible 10 . An emitting device for emitting electromagnetic radiation, in the form of a coil arrangement 30 , is arranged around the crucible 10 . High-frequency power is introduced into a melt 40 , for example comprising lead silicate glass, by means of the coil arrangement, so that the melt 40 is heated. A high frequency of approximately 250 kHz to approximately 400 kHz at an emission power of approximately 200 kW to approximately 300 kW or higher is used. The temperature of the melt is in the range from 1200° C. to 2000° C.
The crucible 10 comprises a water-cooled annular wall section 12 and a water-cooled base 14 . The wall section 12 and the base 14 together form the cooled wall of the crucible 10 and each comprise metal tubes 16 which are arranged in meandering form and are spaced apart from one another, as can be seen most clearly from FIGS. 2 and 3 . The metal tubes 16 have a cross section of approximately 2 cm and gaps of 5 mm between the tubes 16 , so that the crucible wall is initially permeable to liquid when the crucible 10 is unfilled.
On account of the cooling of the wall section 12 and of the base 14 , i.e. the crucible wall, a solid, continuous skull layer 42 of material of the same composition as the melt, i.e. in this exemplary embodiment of glass, is formed in the contact region between the melt 40 and the crucible wall, so that the arrangement formed from the crucible 10 and the solid skull layer 42 becomes liquid-tight. FIG. 1 , which represents a diagrammatic illustration of the crucible, does not show the individual tubes 16 and the skull layer 42 .
Continuing to refer to FIG. 1 , it should be noted that the melting apparatus is operated continuously, so that batch is regularly laid onto the melt through a substantially central opening 20 in a cover 18 of the crucible 10 . Furthermore, melt is continuously removed via an outlet opening 22 of the crucible 10 .
A cooled bridge 24 penetrates into the melt 40 to a depth of at least approximately 3 cm to 5 cm in the vicinity of the outlet opening 22 , in order to keep unmelted or undissolved constituents of the batch away from the outlet opening 22 .
Furthermore the apparatus 1 comprises two burners 26 , 28 which direct flames 27 , 29 onto the contents of the crucible or a surface 41 of the melt 40 through openings in the cover 18 . In this arrangement, the burner 26 is used for initial melting of the contents of the crucible when the apparatus 1 is starting up, for example after a change of crucible, and the burner 28 is used to continuously reheat the melt 40 in the outlet opening 22 .
A mixing or homogenization device in the form of a gas nozzle 50 is arranged at the base 14 of the crucible 10 . The gas nozzle 50 projects into the crucible in sections and introduces the gas into the melt 40 .
Furthermore, the gas nozzle 50 is arranged eccentrically, in this exemplary embodiment approximately halfway between the center and the edge of the round crucible 10 and on the opposite side from the outlet opening 22 . This position has proven highly advantageous since a convective flow 54 , which is in any case present as a result of a temperature difference in the melt and rises centrally from a hot core 43 and then descends at the edge, is boosted and, at the same time, batch which is laid centrally through the opening 20 is kept away from the cold crucible wall 12 by means of the gas bubbles 52 . The substantially annular flow 54 advantageously results in effective mixing and homogenization of the melt and is responsible for a temperature compensation and a uniform distribution of the material in the melt.
In this example, the gas bubbles contain O 2 in order at the same time to oxidize lead in the lead silicate glass melt 40 .
FIG. 2 shows a diagrammatic plan view from above of the crucible base 14 with the gas nozzle 50 , which is arranged in an opening 15 or cutout in the crucible base 14 between the meandering metal tubes 16 .
As is also illustrated in FIG. 3 , the skull layer 42 is formed not only on the cooled base 14 of the crucible, but also on the cooled gas nozzle 50 . However, the escaping gas bubbles 52 ensure that an opening of the gas nozzle is kept clear for prolonged periods.
Nevertheless, the solid skull layer 42 may close up over an outlet opening 56 of the gas nozzle 50 , so that it is no longer possible for gas to escape from the nozzle 50 , for example as a result of an interruption in the gas feed. This situation is illustrated in FIG. 4 . To allow the opening 56 to be opened up again, the gas nozzle comprises a needle 58 which is arranged longitudinally displaceably, in the direction indicated by the arrow 59 , inside a passage 60 in the center of the gas nozzle. Therefore, a tip 62 of the needle 58 can punch through a section 42 a of the skull layer 42 which is above the gas outlet opening 56 , so that the gas outlet opening 56 can be opened up again.
The inventors have discovered that an upper section 51 of the gas nozzle 50 , which projects into the crucible 10 and at least in part is in direct contact with the skull layer 42 , is preferably made from non-contaminating or at least low-contamination material. In the context of the present invention, the term low-contamination is to be considered to encompass materials which substantially have little or no effect on the glass quality. These are in particular light metals, such as for example aluminum. Although aluminum does pass into the melt, aluminum ions or aluminum compounds substantially have little or no adverse effect on the optical properties, in particular the transmission of the glass. On the other hand, cooling of the gas nozzle 50 ensures that the gas nozzle 50 is able to withstand the high temperatures in the crucible 10 .
Furthermore, the use of a metal with a high melting point, e.g. higher than 2000° C., in particular molybdenum, iridium, tungsten or a tungsten compound, has proven advantageous to the needle 58 .
FIG. 5 shows the gas nozzle 50 in longitudinal section. The gas nozzle 50 comprises the gas outlet opening 56 and the gas passage 60 in which the needle 58 runs and is guided. The needle 58 can be displaced inside the gas nozzle 50 , parallel to the passage 60 , by means of a displacement device 64 . Furthermore, the gas nozzle 50 comprises a gas inlet 66 and a seal 68 for the needle 58 . The upper section 51 of the gas nozzle 50 comprises aluminum or an aluminum-containing alloy, with a lower section 53 of the gas nozzle 50 made from brass. The upper and lower sections 51 , 53 are sealed in a fluid-tight manner with respect to one another by seals 70 . In the lower section 53 there is a cooling water inlet 72 and a cooling water outlet 74 , so that the gas nozzle can be effectively cooled by water flowing through it.
Referring to FIG. 6 , which illustrates a cross section through the nozzle, it can be seen that the lower section 53 is divided, parallel to a longitudinal axis L of the gas nozzle 50 , into two halves 53 a , 53 b , which are electrically insulated from one another.
FIG. 7 shows a second embodiment of the apparatus 101 according to the invention, with an alternative device 150 for mixing and homogenizing the melt 40 . Glass batch which has been formed into pellets, coated pills and/or beads 156 is introduced, via a conveyor belt 154 , into the melt 40 through the opening 20 . The glass beads 156 comprise an outer boundary region 158 and an inner core region 160 . The boundary region 158 substantially comprises glass of the same composition as the melt 40 . The core region 160 comprises a substance which releases a gas or gas bubbles 152 in the melt when the boundary region 158 has melted. The substance in the core region 160 may comprise a gas, a liquid, e.g. water, or a solid material, e.g. a salt, which by interacting with the hot melt 40 release the gas bubbles 152 .
The fact that the glass beads 156 sink in a left-hand section 40 a of the melt and the fact that the gas bubbles 152 rise up in a right-hand section 40 b of the melt 40 result in a substantially annular flow being generated or induced within the melt 40 . However, it is also possible, as shown in FIG. 1 , for an existing convective flow to be boosted.
FIG. 8 shows a third embodiment of the apparatus 201 according to the invention, in which batch bodies 256 which have been pressed into the form of rods are introduced into the melt 40 by means of a mixing and homogenization device 250 . The bodies 256 in rod form are, for example, shaped in the style of propellers and rotate as they sink within the melt 40 , with the bodies 256 being melted at the same time, so as to generate flow phenomena in the melt 40 .
FIG. 9 shows a fourth embodiment of the apparatus 301 according to the invention with an agitator 350 which mechanically makes the melt 40 in the melting crucible 10 flow by means of a rotational movement.
FIG. 10 shows a preferred embodiment of an elongate agitator 350 ′. The agitator 350 ′ is substantially produced, e.g. by pressing, from the glass which also forms the melt 40 . The agitator 350 ′ is introduced into the melt 40 from above along its longitudinal axis 352 , for example in a similar manner to the agitator 350 shown in FIG. 9 , and is rotated about its axis 352 . The agitator 350 ′ comprises three agitating arms which extend away from the center and is dissolved of its own accord by melting in the melt 40 . To ensure continuous addition of glass and agitation, the agitator 350 ′ is correspondingly continuously moved in further from above.
FIG. 11 shows the first embodiment of the apparatus 1 according to the invention with a connected refining channel 80 and an additional external homogenization device 90 . Liquid glass is continuously passed out of the crucible 10 , in the direction indicated by arrow 82 , into the refining channel 80 and, from there, in the direction indicated by arrow 84 , onwards into the external homogenization device 90 . The external homogenization device 90 comprises a glass outlet 92 for pouring, e.g. into a mold and/or for further or final processing of the glass to form a glass product or glass-ceramic product.
Refining of the glass in the refining channel 80 and subsequent homogenization in the external homogenization device 90 further improves the quality of the glass. The glass quality achieved with the apparatus according to the invention may, however, already be sufficiently high, so that there is no need for the refining channel 80 and/or the homogenization device, with the result that the glass melt 40 is ready for further or final processing at the outlet opening 22 .
It will be clear to the person skilled in the art that the invention is not restricted to the exemplary embodiments described above and can be varied in numerous ways without departing from the spirit of the invention. | The invention relates to an apparatus and a method for low-contamination melting of high-purity, aggressive and/or high-melting glass or glass-ceramic. According to the invention, for this purpose a melt is heated in a crucible or melting skull crucible by means of high-frequency radiation and is mixed or homogenized in the melting crucible. It is preferable for a gas nozzle, from which gas bubbles, e.g. oxygen bubbles (known as O 2 bubbling), escape into the melt, to be provided at the base of the crucible. This alone makes it possible to achieve surprising multiple benefits in the melting skull crucible. Firstly, unmelted batch which drops into the melt in solid form, for example from above, is melted down more quickly as a result of more intensive mixing with the liquid fraction of the melt, secondly the temperature distribution in the melt is made more even, thirdly a uniform distribution or mixing of different glass constituents is achieved, and fourthly the redox state of the glass can be adjusted. | 8 |
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to semiconductor packaging structures. More particularly, the present invention relates to a manufacturing method for molding image sensor package structure and an image sensor package structure made through the method.
2. Description of Related Art
Conventionally, an image sensor package is made by placing an image sensor chip on a substrate, connecting the image sensor chip and the substrate by means of metal conducting wires, and mounting a transparent lid (e.g. glass) upon the image sensor chip so as to allow light to pass through the transparent lid and get acquired by the sensor chip. The resultant image sensor package is for a system manufacturer to integrate to an external device, such as a printed circuit board, or to apply to any of various electronic products such as a DSC (Digital Still Camera), a DV (Digital Video), a security monitoring system, a mobile phone, or a vehicle image sensing module.
In traditional image sensor package, the transparent lid is adhered beforehand to the image sensor chip for protecting the chip against foreign pollutant particles. After the transparent lid is installed, the metal conducting wires are arranged so as to electrically connect the image sensor chip with the substrate or a carrier. Then, a macromolecular liquid compound is used to cover the metal conducting wires. However, the macromolecular liquid compound is quite costly and needs to be arranged through a time-consuming dispensing process. Consequently, the traditional technology of such image sensor package is disadvantageous in its prolonged processing cycle and high cost.
In addressing the above problems, U.S. Pat. No. 7,312,106 has proposed a method for encapsulating a chip having a sensitive surface. The known method comprises mounting a chip having a sensitive chip surface and contact pads on a carrier having carrier contact pads; bonding the chip contact pads to the carrier contact pads; applying a closed dam around the sensitive chip surface, which defines an open space inside the dam; positioning a lid, which closes the open space inside the dam; positioning the chip and the carrier into a mould; introducing package material into the mould for transfer molding; and conducting a post mold cure process so as to complete encapsulation of the chip.
The upper half of the mould could have an inward-extending section facing the sensitive chip surface so as to facilitate the package material in fully covering around the lid without covering the central upper surface of the lid, thereby protecting the periphery of the lid. However, the inward-extending section could significantly increase the cost for making the upper mould half, and is unfavorable to the purpose of reducing the overall cost of the image sensor package. Although the prior art method might also be accomplished by using a different upper mould half without the inward-extending section, it otherwise requires an additional elastic material settled between the upper mould half and the lid so as to protect the lid from the pressure exerted by the direct application of the upper mould. Even when the elastic material is used, the known method for encapsulating a chip still puts the image sensor in risk from damage, thus leading to a decreased yield rate.
SUMMARY OF THE INVENTION
The present invention provides a manufacturing method for molding image sensor package structure and an image sensor package structure made through the method, wherein by virtue of a dam arranged on a transparent lid, the transparent lid is free from being directly pressed by a mold, thus leading to an improved yield rate.
The present invention provides a manufacturing method for molding image sensor package structure and an image sensor package structure made through the method, wherein by virtue of a dam arranged on a transparent lid, a mold compound is allowed to cover around the chip, the transparent lid and the dam, thereby extending of the blockage to invasive moisture.
The present invention provides a manufacturing method for molding image sensor package structure and an image sensor package structure made through the method, wherein by virtue of a dam that facilitates extending blockage to invasive moisture, the reliability of the image sensor package structure is improved.
The present invention provides a manufacturing method for molding image sensor package structure and an image sensor package structure made through the method, wherein the image sensor package structure is produced by means of molding so as to significantly shorten processing cycle time and increase throughput.
The present invention provides a manufacturing method for molding image sensor package structure and an image sensor package structure made through the method, wherein batch-type production of the image sensor package structure is achieved by means of molding so as to reduce processing costs.
The present invention provides a manufacturing method for molding image sensor package structure and an image sensor package structure made through the method, wherein the disadvantages of the known technology related to the costly liquid compound and the time-consuming dispensing process are eliminated.
To achieve the aforementioned effects, the manufacturing method for molding image sensor package structure of the present invention includes the following steps: providing a half-finished image sensor for packaging, wherein the half-finished image sensor has a substrate including a carrying surface provided with a plurality of first conductive contacts; at least one chip including a first surface, a second surface, and a plurality of second conductive contacts, wherein the first surface is coupled to the carrying surface and the second surface has a sensitization area peripherally surrounded by the second conductive contacts that are electrically connected with the first conductive contacts; and at least one transparent lid settled on the second surface and covering over the sensitization area to define an air cavity over the sensitization area; arranging a dam extending along the upper periphery of the transparent lid; positioning the half-finished image sensor within a mold, wherein the mold includes an upper mold half contacting the upper surface of the dam and a lower mold half contacting the lower surface of the substrate, wherein a mold cavity between the upper mold half and the lower mold half is defined; injecting a mold compound into the mold cavity; and molding the image sensor package structure, opening the mold, and conducting a post mold cure process.
To achieve the aforementioned effects, the image sensor package structure of the present invention includes a substrate having a carrying surface provided with a plurality of first conductive contacts; a chip with a first surface coupled to the carrying surface, a second surface having a sensitization area and a plurality of second conductive contacts surrounding the sensitization area peripherally and electrically connected with the first conductive contacts; a transparent lid settled on the second surface and covering over the sensitization area to define an air cavity over the sensitization area; a dam extending along the upper periphery of the transparent lid; and a mold compound covering around the chip, the transparent lid and the dam at peripheries thereof.
By implementing the present invention, at least the following progressive effects can be achieved:
1. By virtue of the dam arranged on the transparent lid, the transparent lid is free from being directly pressed and damaged by the mold, thus leading to an improved yield rate of the image sensor package structure.
2. By virtue of the dam arranged on the transparent lid, there is no need to make the mold with a custom-made inward-extending section for varying lid dimensions, which significantly reduces costs for preparing the mold.
3. The dam on the transparent lid allows the mold compound to cover around the chip, the transparent lid, and the dam, thereby extending the blockage to invasive moisture.
4. The existence of the dam allows the mold to depress against the top of the dam and allows the mold compound protect the periphery of the transparent lid to prevent moisture from invading the air cavity underneath the transparent lid, thereby improving the reliability of the image sensor package structure.
5. The image sensor package structure is produced by means of molding so as to significantly shorten processing cycle time and increase throughput.
6. The molding formation and batch-type production of the image sensor package structure facilitate the reduction of the processing costs of the image sensor package structure.
7. The disadvantages of the known technology related to the costly liquid compound and the time-consuming dispensing process are eliminated.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention as well as a preferred mode of use, further objectives and advantages thereof will be best understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying drawings, wherein:
FIG. 1 is a flowchart of a first embodiment of a method for molding an image sensor package structure according to the present invention;
FIG. 2 is a schematic structural drawing of a half-finished image sensor for packaging according to the present invention;
FIG. 3A , according to a first embodiment of the present invention, shows the half-finished image sensor for packaging provided with a dam;
FIG. 3B is a top view of the half-finished image sensor of FIG. 3A ;
FIG. 4A , according to the first embodiment of the present invention, shows the half-finished image sensor having the dam enclosed by a mold;
FIG. 4B , according to the first embodiment of the present invention, shows injection of a mold compound into a mold cavity of the mold;
FIG. 4C , according to the first embodiment of the present invention, shows the resultant image sensor package structure after the mold is opened;
FIG. 5A , according to a second embodiment of the present invention, shows the half-finished image sensors for packaging provided with dams;
FIG. 5B , according to the second embodiment of the present invention, shows the half-finished image sensors having the dams enclosed by a mold;
FIG. 5C , according to the second embodiment of the present invention, shows injection of a mold compound into a mold cavity of the mold;
FIG. 5D , according to the second embodiment of the present invention, shows the resultant image sensor package structure after the mold of FIG. 5C is opened;
FIG. 5E , according to the second embodiment of the present invention, shows the package structure of FIG. 5D cut into individuals;
FIG. 6A , according to a first concept of the present invention, shows soldering pads arranged on a lower surface of the substrate; and
FIG. 6B , according to a second concept of the present invention, shows soldering pads arranged on the lower surface of the substrate.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1 , the present embodiment is a method (S 100 ) for molding an image sensor package structure. The method (S 100 ) includes the following steps: providing a half-finished image sensor for packaging (S 10 ); arranging a dam on a transparent lid (S 20 ); positioning the half-finished image sensor within a mold (S 30 ); injecting a mold compound into the mold cavity of the mold (S 40 ); and molding the image sensor package structure, opening the mold and conducting a post mold cure process (S 50 ).
In the step of providing a half-finished image sensor for packaging (S 10 ), as shown in FIG. 2 , a half-finished image sensor 10 for packaging is provided. The half-finished image sensor 10 has a substrate 11 , at least one chip 12 , and at least one transparent lid 13 . Alternatively, as shown in 5 A, multiple said chips 12 are provided on the same substrate 11 for producing multiple said image sensor package structures simultaneously.
The substrate 11 may be one conventionally used in a normal image sensor, and may be a circuit substrate. The substrate 11 has a carrying surface 111 for carrying the chip 12 . In addition, a plurality of first conductive contacts 112 is formed on the carrying surface 111 , as shown in FIG. 3B .
The chip 12 has a first surface 121 coupled to the carrying surface 111 of the substrate 11 so that the chip 12 is mounted on the substrate 11 . Furthermore, a glue layer 113 may be provided between the chip 12 and the substrate 11 for adhering the chip 12 onto the substrate 11 . The chip 12 may be a CMOS (Complementary Metal Oxide Semiconductor) image sensing chip or a CCD (Charge Coupled Device) for sensing light. In addition, the chip 12 has a plurality of photosensitive elements and a plurality of second conductive contacts 124 , as can be seen in FIG. 3 B. Therein, the photosensitive elements are settled on a second surface 122 of the chip 12 so as to form a sensitization area 123 . The second conductive contacts 124 are arranged to surround the sensitization area 123 and are electrically connected with the photosensitive elements. Moreover, the second conductive contacts 124 on the chip 12 and the first conductive contacts 112 on the substrate 11 may be electrically connected with each other through metal conducting wires 15 formed by wiring. The first surface 121 of the chip 12 refers to the lower surface of the chip 12 while the second surface 122 of the chip 12 refers to the upper surface of the chip 12 .
The transparent lid 13 serves to protect the sensitization area 123 on the chip 12 against contaminants while allowing light to pass therethrough and enter into the sensitization area 123 of the chip 12 . An adhesive layer 14 attaches the transparent lid 13 to the second surface 122 of the chip 12 so that the transparent lid 13 covers over the sensitization area 123 and so that an air cavity is defined between the transparent lid 13 and the chip 12 . The adhesive layer 14 may be made of epoxy resin. Since the adhesive layer 14 is sandwiched between the sensitization area 123 and the second conductive contacts 124 , it does not overlap with the sensitization area 123 , and thus the chip 12 is ensured with the optimal light-sensing effect.
In the step of arranging a dam on a transparent lid (S 20 ), referring to FIGS. 3A and 5A , a dam 20 is set on the transparent lid 13 in such a way that it extends along an upper periphery of the transparent lid 13 while keeping away from the sensitization area 123 of the chip 12 , as shown in FIG. 3B . Thereby, light is still allowed to pass through the transparent lid 13 and enter into the sensitization area 123 of the chip 12 without any complications. The dam 20 may be made of epoxy resin or a film. The epoxy resin or film are prearranged at a predetermined location and treated with ultraviolet or baked to a semi-cured state for being properly elastic and then receives a post mold cure process to become completely cured.
In the step of positioning the half-finished image sensor within a mold (S 30 ), referring to FIGS. 4A and 5B , the mold comprises a lower mold half 31 and an upper mold half 32 . Therein the lower mold half 31 is settled at the lower surface 114 of the substrate 11 and contacts the lower surface 114 of the substrate 11 , while the upper mold half 32 has its lateral wall 321 mounted on the upper surface of the substrate 11 so that the substrate 11 has its carrying surface 111 and lower surface 114 sandwiched between the upper mold half 32 and the lower mold half 31 . Additionally, the upper mold half 32 has a planar inner upper surface for contacting the upper surface of the dam 20 so as to define a mold cavity 33 between the upper mold half 32 and the lower mold half 31 .
In the step of injecting a mold compound into the mold cavity of the mold (S 40 ), as shown in FIGS. 4B and 5C , the mold compound 40 is injected into the mold cavity 33 formed between the upper mold half 32 and the lower mold half 31 so that the mold compound 40 encapsulates the metal conducting wires 15 therein and covers around the chip 12 , the transparent lid 13 and the dam 20 at peripheries thereof. Since the dam 20 acts as a barricade between the transparent lid 13 and the upper mold half 32 , the mold compound 40 is blocked outside the transparent lid 13 from overflowing into the central region of the transparent lid 13 . Furthermore, the upper mold half 32 directly presses upon the dam 20 so as not to directly contact the transparent lid 13 , thereby protecting the transparent lid 13 from damage or surface contamination.
In the step of molding the image sensor package structure, opening the mold and conducting the post mold cure process (S 50 ), the upper mold half 32 and the lower mold half 31 help the mold compound 40 to undergo transfer molding. After the mold is opened, a post mold cure process is conducted as to produce an image sensor package structure as shown in FIG. 4C . During the progress of post mold cure, the dam 20 also becomes completely cured.
The disclosed method may further include a step of placing solder balls. Referring to FIGS. 4C and 5D , solder balls 50 may be attached to the lower surface 114 of the substrate 11 . The solder balls 50 are also electrically connected to the first conductive contacts 112 on the carrying surface 111 by way of the circuit structure of the substrate 11 , which allows the image sensor package structure to electrically connect with external circuit devices.
Since the mold compound 40 is more inexpensive than the conventionally used liquid compound, substitution of liquid compound with the mold compound 40 helps to significantly reduce material costs for packaging. Furthermore, coating of the conventionally used liquid compound requires the known dispensing process that prolongs the processing cycle. On the other hand, the transfer molding process of the mold compound 40 achieves the purpose of forming in a significantly reduced cycle time, thereby improving throughput and in turn lowering the overall manufacturing costs. Moreover, the dam 20 additionally mounted on the transparent lid 13 serves as a mount for the mold compound to seal off the transparent lid and prevent invasive moisture from seeping into the chip 12 , thereby vastly improving the reliability of the image sensor package structure.
Furthermore, as shown in FIGS. 5A through 5E , the above method (S 100 ) for molding the image sensor package structure may be applied to producing multiple said image sensor package structure at the same time. In this alternative application, the substrate 11 carrying multiple said chips 12 is positioned within a mold, as shown in FIG. 5B . The mold compound 40 is injected into the mold cavity 33 of the mold, as shown in FIG. 5C , so that the mold compound 40 later undergoes transfer molding, mold opening and the post mold cure process. Additionally, placement of solder balls 50 may be conducted after the post mold cure. The solder balls 50 may be electrically connected to the first conductive contacts 112 on the carrying surface 111 by way of the circuit structure of the substrate 11 so that the solder balls 50 allow the image sensor package structure to electrically connect with external circuit devices. At last, as illustrated by FIGS. 5D and 5E , the finished image sensor package structure, after the post mold cure and placement of the solder balls 50 , may be cut by means of any existing cutting technology to become plural image sensor package structures, as package individuals, so as to improve efficiency of the throughput.
Referring to FIGS. 6A and 6B , in addition to the solder balls 50 , soldering pads 60 may be arranged on the lower surface 114 of the substrate 11 . The soldering pads 60 are electrically connected to the first conductive contacts 112 of the circuit structure of the substrate 11 so that the soldering pads 60 allow the image sensor package structure to electrically connect with external circuit devices. Preferably, the soldering pads 60 may be arranged along the lower periphery of the lower surface 114 , as shown in FIG. 6A , or may be arranged into an array, as shown in FIG. 6B .
The molded image sensor package structure is thus suitable for vehicle image sensors to give the advantage of effectively blocking moisture invasion.
The embodiments described above are intended only to demonstrate the technical concept and features of the present invention so as to enable a person skilled in the art to understand and implement the contents disclosed herein. It is understood that the disclosed embodiments are not to limit the scope of the present invention. Therefore, all equivalent changes or modifications based on the concept of the present invention should be encompassed by the appended claims. | A manufacturing method for molding an image sensor package structure and the image sensor package structure thereof are disclosed. The manufacturing method includes following steps of providing a half-finished image sensor for packaging, arranging a dam on the peripheral of a transparent lid of the half-finished image sensor, positioning the half-finished image sensor within a mold, and injecting a mold compound into the mold cavity of the mold. The dam is arranged on the top surface of the transparent lid and the inner surface of the mold can exactly contact with the top surface of dam so that the mold compound injected into the mold cavity is prevented from overflowing to the transparent lid by the dam. Furthermore, the arrangement of the dam and the mold compound can increase packaged areas and extend blockage to invasive moisture so as to enhance the reliability of the image sensor package structure. | 7 |
FIELD OF THE INVENTION
This invention is directed to an improved process for dotting molding tools with droplets. More particularly, this invention is directed to an improved process and apparatus for dotting molding tools with droplets of liquid or suspended lubricant in the production of molded articles in the pharmaceutical, food, or catalyst field.
BACKGROUND OF THE INVENTION
U.S. Pat. No. 4,323,530, incorporated herein by reference, describes a process for compressing granulates to form tablets, coated tablet cores, and the like wherein before each compression process a certain amount of lubricant in liquid or suspended form is applied to the affected zones of the pressing tools by means of an intermittently operating nozzle system. This type of lubrication ensures that no lubricant, such as magnesium stearate, has to be added to the granulate which is to be compressed. This results, for example, in pharmaceutical compositions with a substantially better bioavailability of the active substance contained therein; moreover, significantly reduced quantities of lubricant are required. According to the process described in this patent, the lubricant is applied by means of directed spraying of specific zones of the pressing tools with the liquid or suspended lubricant by use of preferably single-substance or two-substance nozzles or dies. However, when these nozzles are used, and particularly when two-substance nozzles are used wherein air and lubricant liquid are delivered simultaneously, it has been found that droplets form with a particle spectrum which depends in its breadth upon the supply of air. These nozzles tend to produce an undesirable mist, which can lead to contamination of the tablet press, particularly the pressing plate.
The use of single-substance nozzles through which the liquid lubricant is sprayed intermittently onto the corresponding parts of the pressing tools just before each separate pressing operation has also demonstrated a tendency to contaminate the tablet-pressing plate due to the formation of a cone of spray or the occurence of stray drops of different diameters within the boundaries of the spray cone. However, when used in fast-operating tablet presses with actuating intervals of up to 5 msec the single- and two-substance nozzles also fail to give a constant dissolution of the liquid lubricant, and they generate not only individual droplets but also sequences of drops consisting of drops having different diameters. The result is that there is no guarantee of a constant action over the intended zones of the pressing tools.
It has already been proposed (cf., German Offenlegungsshrift No. 29 32 069) that these disadvantages by overcome by dotting the liquid or suspended lubricant, before each pressing operation, onto the affected zones of the pressing tools in defined quantities and in the form of discrete droplets of defined volume by means of a piezoelectric transducer in conjunction with corresponding nozzles in a directed manner. However, a certain disadvantage of this process is that the liquids to be sprayed are subject to stringent requirements with regard to their viscosity and surface tension. Only if certain limits are adhered to for the viscosity and surface tension is it possible to dot the liquids satisfactorily over the intended pressing zones. Moreover this system is sensitive to dust and is not readily suitable for the lubrication of pressing tools for compressing powdery or nongranulated materials with a high powder content, such as, for example, sorbitol compositions in the food industry.
OBJECTS OF THE INVENTION
It is an object of the invention to provide an improved process for dotting molding tools with droplets.
It is also an object of the invention to provide an improved process and apparatus for dotting molding tools with droplets of liquid or suspended lubricant in the production of molded articles in the pharmaceutical, food, or catalyst field.
These and other objects of the invention will become more apparent in the discussion below.
BRIEF DESCRIPTION OF THE INVENTION
FIG. Ia represents a cross-sectional view of a member of an apparatus according to the invention;
FIG. Ib represents a plan view of the member shown in FIG. Ia:
FIGS. IIa and IIb represent a plan view and a cross-sectional view, respectively, of a member having a configuration different from that shown in FIGS. IIa and IIb;
FIG. III represents a cross-sectional view of a further such member; and
FIG. IV represents a cross-sectional view of an apparatus according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
During further investigation and development of the method described in U.S. Pat. No. 4,323,530, it has been found that all the negative side-effects can be virtually eliminated if valve systems based upon the electromagnetic or piezomechanical or piezoelectrical effect and operating in a range of from about 50 μsec. to 5 msec., preferably from about 1 to 2 msec., alternately released defined quantities of liquid, dissolved, or suspended lubricants and defined volumes of gases, e.g., air, via one or more capillary systems, which are in turn provided with nozzle openings. The jet of gas released afterwards not only causes the meniscus of the lubricant liquid or suspension to bulge up at the surfaces of the nozzle but also ensures satisfactory detachment of the droplets at the "alternating single-substance nozzles" and speeds the droplets in their flight towards the zones of the pressing tools which are to be treated.
The term "alternating single-substance nozzles" was chosen because, unlike known single-substance and two-substance nozzles, in this case the two substances, liquid and gas, leave the same nozzle opening one after another in an alternating sequence. At the same time, the jet of gas also cleans the nozzle thoroughly thus, the nozzle opening is cleaned continuously and in pulses.
To obtain a controlled droplet formation, the ratio between the pressure of the liquid and the quantity of liquid per unit of time and the pressure and quantity of gas per unit of time, as well as the nature of the capillary and nozzle system, are of great importance. Generally, at the gas pressures which are preferably used, a from about 10 to 50 times greater quantity of gas by volume, based upon the volume of the liquid, for the same unit of time is sufficient. The alternating method of operation of the valve system leads to a clean detachment of the droplets of lubricant from the nozzle opening, without any undesirable misting of the lubricant. Individual droplets of liquid are formed, detached from the nozzle, and guided and speeded towards the zones which are to be treated. The formation of any mist is avoided, and hence contamination of the tablet-making machine is averted. The acceleration of flight of droplets towards the pressing tools also makes it possible to use this apparatus in very fast-running tablet-making machines (with a circumferential speed of punch of up to about 10 m/sec.).
If a plurality of nozzles are used, these may be arranged in a row or distributed over an area of the surface and, optionally, also over the lower surface of a so-called dotting shoe. The mounting of the nozzles on a dotting shoe of this kind depends upon the shape and size of the pressed articles. The dotting shoe itself is preferably mounted immediately in front of the filling shoe between the matrix plate and the upper die so that the droplets of lubricant delivered arrive by the shortest possible path and in the right direction on the active surface of the pressing tools which they thus lubricate. The term "liquid lubricants" also covers molten lubricants.
Each capillary in the dotting shoe is attached to a valve system either per se or together with certain associated capillaries. The valve system alternately releases a small but defined quantity of lubricant and gas or air on each actuation. The actuation of the valve system and the starting up of the control program are effected by means of a light barrier mounted up on the tablet-making press, by means of a bit transmitter, or by means of a capacitive or inductive proximity switch using electrical, magnetic, or mechanical (e.g. pneumatic) pulses which act upon the valves.
Thus, the principle according to the present invention consists of the metering of a small but defined quantity of liquid lubricant into the capillary system of the dotting shoe, the subsequent release of droplets of lubricant from the nozzle opening, and application of the released lubricant droplets onto the intended zones of the pressing tools by means of a metering volume of gas (e.g., air) which flows in afterwards, this metered gas simultaneously accelerating the droplets by a predetermined amount, which can be predetermined by adjusting certain pulse magnitudes. The quantity of gas or air is made such that it does not cause uncontrolled decomposition and hence atomization of the drops.
The pulse time for metering the lubricant liquid or suspension is preferably kept greater than the pulse time for metering the air. However, it is advisable to keep the pressure of the lubricant liquid or suspension lower than the pressure of the air which follows. It has proven advantageous to have the pulse for the metering of the air occur at the moment that the metering of lubricant ends.
Generally, nozzle outlet openings of from about 0.05 to 0.3 mm are used, with a liquid pressure of from about 0.1 to 2 bar and a gas pressure of from about 0.5 to 8 bar. The pulse times for metering the liquid are then preferably from about 1.0 to 2.5 msec, and the pulse times for metering the gas are from about 1.0 to 2.0 msec. If the above criteria are followed, a quantity of lubricant of about 10 to 500 gm/hour can then be delivered through an alternating single-substance nozzle. With a tablet-making speed of 200,000 pressed articles per hour, the diameter of the pressed articles being 19 mm and their weight being 2.0 gm, the lubricant would be applied to the upper and lower dies by means of, for example, ten alternating single-substance nozzles each of which releases from about 0.5 to 25 mg of lubricant liquid onto the upper and lower dies.
In the case of capillaries with several nozzle outlet openings along the path of the capillary, there may be a drop in pressure in the region of the nozzle outlet openings at the ends, and this will result in impaired detachment of the droplets from these nozzle openings. To avoid such disruption of the release of droplets, it is advisable to taper the capillaries toward the nozzle openings at the ends. This tapering may be either stepwise or conical.
The lubricant liquid generally contains from about 5 to 50% by weight of lubricant, the remainder being a solvent or suspension agent. In the case of lubricating oils or molten fats, the concentration is 100% lubricant. Thus, for each pressed article (19 mm in diameter, 2.0 gm in weight), 0.025 to 25 mg of lubricant liquid, i.e., from about 0.001 to 1% by weight, based upon the the weight of the final tablet, are delivered, dependent upon the concentration of the lubricant liquid. The preferred range of lubricant liquid is from about 0.1 to 2 mg (from about 0.005 to 0.1% by weight). The lubricants may be stearic acid, palmitic acid, alkali metal or alkaline earth metal salts of these acids, such as magnesium stearate, potassium stearate, or aluminum stearate, and also mono-, di-, and triglycerides and mixtures thereof of medium- to long-chained fatty acids, such as glycerol monostearate or glycerol monlaurate. Particularly suitable solvents and suspension agents include water and alcohols such as ethanol, isopropanol, or mixtures thereof. The viscosity of the lubricant solutions is preferably from about 2 to 100 mPa·s (millipascal seconds), while the surface tension is from about 20×40 nM/m (millinewtons per meter). In the case of more viscous lubricants the viscosity can be reduced significantly by heating to 100° C. Naturally, it is possible to go significantly below or above the values given hereinbefore, dependent upon the properties of the lubricants to be used.
While the active surfaces of the pressing tools are guided past above and below the dotting shoe, the lubricating process, consisting of the metering of lubricant and air, is initiated once or several times, so that the pressing tools are dotted with the lubricant over their surface. Dependent upon the shape of the pressed article, all the nozzles or only some of the nozzles may be activated to release drops. In principle, each nozzle may also, if desired, be actuated separately. Zones in the pressing tools which are subject to particle stress, e.g., zones for forming engraved designs in the pressed article, may be preferentially dotted with drops of lubricant. This is achieved by a higher alternating pulse sequence in the capillaries provided for this purpose. The dotting shoe may also be divided into two separate units which are mounted offset from one another in the press and dot the upper die and pressing chamber or lower die separately. The arrangement of the nozzles over the surfaces of the dotting shoe generally depends upon the geometry of the zones of the pressing tools subject to particular stress in the pressing operation, with the zones subject to great stress being dotted with more lubricant than zones subject to less stress.
To achieve clean detachment of the drops of lubricant from the opening or openings of the nozzles in the dotting shoe, both the control program, nozzles, and capillary system, and also the physical characteristics of the lubricating liquid and the air supply, must be coordinated with the speed of the tablet-making presses. The viscosity and surface tension of the lubricating liquid helps to stabilize the formation of droplets and make it easier or more difficult to release the droplets from the nozzle opening, but a particular advantage of this process according to the invention is that it is possible to adjust the viscosity and surface tension over a very wide spectrum, for example, by varying the metering and the cyclical sequences of liquid or air or by making modifications in the capillary system or in the nozzle openings. Another possibility is to introduce warm air into the dotting shoe, the temperature being as high as about 100° C. The warm air ensures that, for example, when lubricant solutions are used, the solvent in the droplets is already substantially evaporated when the droplets make contact with the tools. This prevents any solvent from penetrating into the granulate or into the tablets. Thus, the air not only has the job of aiding the metering and acceleration of the droplets but may also have a drying function.
It was not readily foreseeable that it would be possible to avoid misting by maintaining certain conditions with regard to the pressure of liquid, the quantity of liquid, the pressure and quantity of air, and the time sequence of metering these media into the capillaries of the dotting shoe, with all the droplets of lubricant being dotted only in discrete form on to the pressing tools.
It has proven advantageous for the withdrawal force of the pressed blanks, which is measured by means of strain gauges, to be used as a regulator for the number of droplets of lubricant per unit of time (e.g., per second). If the strain gauges under the pressed blanks indicate an increase in the withdrawal force, the number of droplets per unit of time is automatically increased. This is achieved by the fact that the measured values obtained, e.g., in digital form, influence the times of opening of the lubricant valves within certain limits by means of the electronic controls.
Unlike the known two-substance nozzles wherein air and liquid are discharged simultaneously and misting often occurs, it is thus possible with the process according to the invention to apply a certain number of droplets of equal diameter to a specific surface of the pressing tool even at very high speeds of the tablet press (circumferential speeds of the punch up to 10 m/sec.).
As a result of the accurate application of lubricant to the active pressing surface of the lower die and the creeping qualities of the lubricant used, obviously enough lubricant will reach the matrix wall when the lower die is removed. The lower die can thus be dotted immediately after the tablet has been ejected before the die being submerged below the filling shoe. A particular advantage of this system is that it is not generally necessary to lower the bottom die so that the dotting shoe can lubricate the free wall of the matrix. It has also been found that direct lubrication of the tablet-making tools is exceptionally effective. Thus, with the conventional two-station high power presses, i.e., wherein one punch presses two tablets per revolution, it is generally sufficient to lubricate the tool once per revolution.
As already mentioned hereinbefore, the invention also relates to an apparatus for dotting molding tools with droplets of liquid or suspended lubricant. The apparatus consists of a dotting shoe with single substance nozzles abutting on capillaries and with separating feed lines for the lubricant liquid or suspension and for the gas abutting on the other ends of the capillaries. Fast-action valves for releasing defined quantities of liquid or gas are mounted in the liquid and gas lines. The pressure in the feed line systems is regulated absolutely and relative to one another by means of pressure regulating valves. All the valves may, for example, be regulated by means of an electronic regulating system.
The invention can perhaps be better understood by making reference to the drawings, which represent preferred embodiments of the invention. FIG. Ia represents a cross-sectional view through a dotting shoe (5) consisting of capillary (1) with a fork which is formed by compressed air feed line (2) and lubricant feed line (3). The capillary (1) has a plurality of nozzles (4) in a row, and this row is also continued on the opposite side.
FIG. Ib represents a plan view of the dotting shoe with a row of nozzle openings (4a).
The drawing of FIG. IIa represents a plan view of a round dotting shoe (5) with a number of nozzle openings (4a) arranged in a geometric distribution and with feed lines (2) and (3) for the lubricant solution or suspension and for the air. FIG. IIb shows a cross-sectional view through the same dotting shoe, with reference numeral (4) indicating the nozzles. The supply of lubricant liquid or suspension and air through the channels (2) and (3), respectively, is continued either by means of a capillary system (not shown) to the individual nozzles or to a row of nozzles, so that it is possible to eject lubricant and air from individual nozzles or from geometrically associated nozzles independently of one another in individual sequences, or else the feed lines (2) and (3) end in the capillary-like chamber (6) from which individual nozzles (4) lead away on one or both sides at right angles or at a specific angle to the plane of symmetry of the dotting shoe.
FIG. III represents a cross-sectional view through a dotting shoe (5) which is particularly adapted to the matrix and upper die. In this figure, reference numeral (1) indicates the capillaries; the feed lines for air and lubricant which converge in a fork are not shown. Reference numeral (4) indicates the nozzles, (7) is the upper die, (8) is the lower die, and (9) is the matrix. The nozzles are arranged at various angles relative to each other and to the axis of the dotting shoe and thus make it possible to provide particularly intensive lubrication of the active pressing surfaces of the upper die and matrix wall.
FIG. 4 represents a cross-sectional view through a lubricant dotting apparatus according to the invention in a tablet-making machine. In this figure, reference numeral (1) is a capillary in the dotting shoe (5) with the fork of the compressed air feed line (2) and lubricant feed line (3) and a row of nozzles (4). The dotting shoe (5) is mounted excentrically relative to the axis of the lower die (8) and upper die (7). Reference numeral (9) designates the matrix, and valves (10a) and (10b) are for releasing compressed air from the compressed air tank (11) and for guiding the lubricant out of the lubricant tank (12).
Reference numeral (13) indicates pressure valves for regulating the pressure of the two media, namely, air and lubricant liquid. These pressure valves permit individual adjustment of the pressure of the liquid and also of the air, and also make it possible to coordinate these pressures with one another. The apparatus also has proximity switch (14) and an electronic control apparatus (15) for controlling valves (10a) and (10b).
The following examples are intended to illustrate the invention and should not be construed as limiting it thereto.
EXAMPLES
Examples of the Preparation of Pressed Articles
EXAMPLE 1
Compressed sorbitol tablets (15 mm in diameter) were produced by the method according to the invention, with direct lubrication, a coating shoe as shown in FIG. 1a being used and the remainder of the apparatus being as described in the invention. The operation was done at a rate of 180,000 tablets per hour, with use of 900 gm per hour of a lubricant consisting of 4% by weight of stearic acid and 20% by weight of capryl/capric acid triglyceride in ethanol.
The liquid was metered into the dotting shoe under a pressure of 1.5 bar for 1.5 msec., and then air was metered at a pressure of 3.5 bar at a pulse width of 2.5 msec. This process, which was initiated by an induction switch, was repeated twice for each pressing tool and pressing operation.
The tablets thus obtained showed no negative changes in their surface quality compared with compressed tablets produced in the traditional way. On the other hand, the flavor was much better than that of the sorbitol tablets produced by the conventional method with the addition of magnesium stearate. By contrast, an electron scan microscope picture of a plane of fracture of a tablet showed that due to the absence of lubricant, the sorbitol crystals were totally sintered together. On the tongue, the tablets did not feel rough at all. Moreover, the desired hardness was achieved with a compressing force reduced by at least 30%.
EXAMPLE 2
Compressed tablets (12 mm in diameter) of acetylsalicylic acid lactose/starch were produced by the process according to the invention, with direct lubrication, with use of a dotting shoe as shown in FIG. 1a and the remainder of the apparatus being according to the invention. The operation was carried out at a rate of 180,000 tablets per hour, with use of about 100 gm of a lubricant consisting of 4% by weight of stearic acid and 6% by weight of polyoxyethylene sorbitan monooleate in ethanol. The liquid was metered into the dotting shoe under a pressure of 0.8 bar for 1.0 msec., and then air was metered out at 1.5 bar and at a pulse width of 2 msec. This process, which was initiated by an induction switch, was repeated three times for each pressing tool and pressing operation.
The tablet had a 35% high breaking strength for the same pressing force. Since the granulate was not mixed with a hydrophobic lubricant, the disintegrant can become fully active. The decomposition of the tablet was reduced from 65 to 10 seconds.
EXAMPLE 3
Compressed sorbitol tablets (15 mm in diameter) were produced by the process according to the invention, with direct lubrication, a dotting shoe as shown in FIG. IIa being used and the remainder of the apparatus being according to the invention. The operation was carried out at a rate of 180,000 tablets per hour, with use of about 700 ml of a lubricant consisting of 4% by weight of stearic acid and 20% by weight of capryl/capric acid triglyceride in ethanol. The liquid was metered into the dotting shoe at a pressure of 1.0 bar for 2.0 msec., and then air was metered out at a pressure of 5 bar and a pulse width of 1.0 msec. This process, which was initiated by an induction switch, was repeated twice for each pressing tool and pressing operation.
The resulting tablets had the same properties as the tablets prepared according to Example 1. Similar results were also obtained when a lubricant consisting of 5% by weight of glycerol monostearate, in a extremely fine suspension in water, was used.
Effervescent Tablets of Ascorbic Acid
EXAMPLE 4
Ascorbic acid, sodium bicarbonate, citric acid, dry flavoring, and sugar were individually screened and then mixed together. Tablets weighing 3.5 gm each were prepared from the mixture in a tablet press fitted with a dotting shoe, by use of the process according to the invention, with direct lubrication of the pressing tools. The lubricant fluid contained, in ethanol, 2% by weight of polyethyleneglycol 6000 and 3% by weight of a glycerol/polyethyleneglycol oxystearic (CREMOPHOR RH40®, available from BASF, Ludwigshafen), the liquid pressure was 1.5 bar, and the pulse width was 2.5 ms. Air was metered out at 3.5 bar at a pulse width of 3 msec. The quantity of lubricant used per tablet was 0.4 mg.
In comparison to a conventional process, there are a number of advantages in the production of effervescent tablets. For example, there are the following:
1. Any conventional tablet press can be used.
2. There is no need for a lower die with a felt packing, specially drilled matrices, and specially lined upper and lower dies.
3. The service life is considerably longer, and the cleaning maintenance required for the machine is greatly reduced.
4. The tablet-making rate can be increased substantially.
5. There is no danger of the effervescent tablets adhering to the dies.
Catalyst Tablet
EXAMPLE 5
A mixture of silicon dioxide, aluminum oxide hydrate, and chromium oxide (Cr 2 O 3 ) with a particle size of between 0.1 and 1 mm was combined and compressed in a tablet press to form cylinders measuring 8 mm in diameter and 5 mm high. The machine was fitted with a dotting shoe. The lubricant liquid consisted of thin paraffin oil. The pulse width of the metering valve was coupled with the measured values for the ejection force. For this purpose, the ejecting bar was fitted with strain gauges so that the force for ejecting each tablet from the matrix could be measured (for an increase in the ejection force, the quantity of lubricant liquid released is also increased). Normally, 0.5 mg of paraffin oil would be required for each tablet.
This catalyst tablet has a number of advantages over catalyst tablets produced by the conventional method. Since there is no hydrophobic lubricant inside, the tablets are about 50% harder. This is of great importance since the charging of tube-shaped reactors with a length of several meters and the temperature conditions during the process require maximum compressive strength, wear strength, and inner cohesion of the tablets. The hardness of the new tablets is so good that there is no need to add a binder such as calcium aluminate cement in the usual way. This in turn increases the purity of the catalyst, thereby benefiting the degree of use and the service life of the catalyst.
While the present invention has been illustrated with the aid of certain specific embodiments thereof, it will readily be apparent to others skilled in the art that the invention is not limited to these particular embodiments, and that various changes and modifications may be made without departing from the spirit of the invention or the scope of the appended claims. | The invention is directed to a process for dotting molding tools with droplets of liquid or suspended lubricant in the production of shaped articles in the pharmaceutical, food, or catalyst fields. Pressurized lubricant solutions or suspensions and pressurized gas are alternately passed through capillaries, in conjunction with alternating single-substance nozzles, in such a way that drops are formed on the nozzle surface, in between the jets of gas, and are then detached form this surface and directed to specific zones of pressing tools. The apparatus comprises fast-acting valves for the brief release of pressurized gases and lubricant liquids or suspensions. The delivery lines of a gas valve and a liquid valve combine upstream of a capillary, and single-substance nozzles are mounted at the end of the capillaries. | 8 |
FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to a comber machine having a nipper head and an assembly of detaching rolls, wherein the nipper and the detaching rolls can be moved relative to each other during a combing cycle.
Modern combers go back to the pioneering designs of John William Nasmith, of about 1920. They feature oscillating nippers, reversing detaching rolls, half-lap and cleaning brushes. The separation of the fiber assembly is effected by a simultaneous back oscillation of the nippers, and a forward rotation of the detaching rolls. The detaching rolls then reverse, and in this way feed the combed tuft back again, in such a manner that the newly-combed fiber tuft can be laid on it. This is the process known as "piecing".
The quantity of comber noil which is screened out is determined by the detachment length, which is referred to as the "ecartement" (separation). By definition, the ecartement is that distance which pertains between the clamping line of the inner detaching rolls and the clamping line of the nipper knife and the cushion plate, when the oscillating nipper is closest to the clamping line of the inner detaching rolls.
The size of the ecartement determines the length of the fiber tuft which protrudes freely when the nippers are closed, and is combed through by the needle segment of the half-lap. With the fiber length distribution in the fiber tuft remaining uniform, the greater the ecartement, the more fibers are combed out. Accordingly, as the ecartement increases, so the amount of separated comber noil rises and, conversely, as the ecartement decreases the amount of noil drops. All known combers essentially control the separation of the noil due to the possibility of changing this "ecartement" value, which is determined on the machinery side, with the ecartement essentially being altered by the readjustment of the outer reversing point of the nipper movement (U.S. Pat. No. 3,479,699=Switzerland Patent 485 873). The axes of the driven detaching rolls are spatially fixed. The detaching rolls only carry out an oscillating, step-and-repeat (pilgrim step like) type of rotational movement, in order to allow for the separation of the fiber assembly and the piecing.
The adjustment of the ecartement by changing the nipper movement is, from the mechanical point of view, relatively easy to carry out in the main drive unit. It is necessary, however, for the machine to be shut down, and for the adjustment to be carried out in the hot and oily gearbox. To obtain an exact adaptation of the amount of noil, the procedure needs to be repeated frequently, resulting in considerable expenditure of time and loss of production.
In addition to the gearbox-side adjustment of the noil separation in U.S. Pat. No. 3,479,699, it is also possible to effect an adjustment of the separation by making provision for swivelling the upper, inner detaching roll about the axis of rotation of the lower detaching roll, in order at least to reduce the amount of work involved when making only minor adjustments to the ecartement.
In the wool processing industry in particular, combers are known which do not follow Nasmith' design principle (see UK-Patent 1 207 441), but rather the older design by Hellmann. In this case, the detachment movement is effected not by the nippers swinging backwards, but exclusively by a corresponding movement of the axis of the detaching rolls in forward direction. The nipper moves up and down in the rhythm of the rotation of the machine; the detaching rolls move in the rhythm of the machine both rotationally as well as in a transitional direction from rear to front and back again. As a result, per machine cycle, the axis of the detaching cylinder moves outward in one movement, and then back in again. The separation as in the case of the Nasmith machine is determined by adjusting the inside reversing point of the detaching roll oscillation.
In view of the fact that the oscillating masses are high in this type of design, large forces of inertia are produced if the detaching rolls move abruptly. The Heilmann design is therefore not well-suited for high combing cycle frequencies, and therefore not for combers with high production rates.
SUMMARY OF THE INVENTION
The task of the invention is to provide improvements to a comber of the type described above which will allow for the simple and rapid adjustment and setting of the ecartement, without the machine necessarily having to be taken out of production.
According to the invention, this task is accomplished by a comber machine having a nipper head and an assembly of detaching rolls which can be moved relative to each other during a combing cycle, and wherein bearings supporting the rolls are displaceable along a track.
This enables the comber noil separation to be changed very simply at any time, even with the machine running, either progressively or in small increments. The control, and adaptation of this vital characteristic value, "noil separation" in a spinning mill is accordingly faster, with higher precision, with less time expenditure, and without loss of production.
The adjustment of the ecartement value, according to the invention, is attained by an independent joint displacement of all aligned detaching rolls. Displacement can be linear, on an arc, or on any other curve which is to the purpose. Relative to the movement of the machine and the combing process, the displacement of the detaching rolls is relatively minor, and the adjustment is effected independently of the machine cycle. The functions of the detaching rolls (drawing-off and piecing) continue to be effected by the known step-and-repeat type of rotational movement.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is explained by way of examples based on the appended schematic representations. These show:
FIG. 1: A side view of the essential parts of a comber, with the movement and setting mechanism for the ecartement;
FIG. 2: A representation of the drive system for the detaching rolls; and
FIG. 3: A side view of a further embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows the principle structure of a comber as described and shown specifically in the aforementioned U.S. Pat. No. 3,479,699. In the machine frame 1, a nipper head 3 is mounted so as to be swingable about a nipper axis 2, a half-lap 4 with a needle segment element 5 being associated with the nipper head 3. The nipper head 3 cooperates with detaching rolls 6. A fiber assembly or wad 7 delivered for combing is conducted continually to the nipper head 3 from a lap (not shown). The advancing end of the wad 7, emerging from the nipper, is referred to as the fiber tuft 10, and is conveyed away after piecing with the combed material of a web 11. The web 11 is held between the detaching rolls 6 and fed back in a step-and-repeat type of movement (pilgrim step like), and is detached from the following fibers of the wad 7. The needle segment 5 is cleaned of the comber noil which is combed out of the freely-suspended fiber tuft 10 by means of a brush roller, not shown, which rotates in the same direction as the half-lap 4 at a higher rate of speed.
The nipper head 3 features a lower nipper plate 13 and a nipper knife plate 21, mounted on bearings in a swingable manner. The lower nipper plate 13 consists essentially of a nipper plate arm 15 and a cushion blade 16 secured to it. At a lateral swivelling journal 17 of the lower nipper plate 13, an upper nipper plate 14 is swingably mounted on bearings; in the lower nipper plate 13, a feed roller 18 for the wad 7 is also mounted on bearings. This converts the continuous fiber feed into a discontinuous feed. An intermittent drive of the feed roller 18 is accomplished in the rhythm of the nipper head movement, by means of a pawl drive which is not shown, but which is described in the aforementioned U.S. Pat. No. 3,479,699.
The upper nipper 14 consists essentially of a nipper knife arm 20 linked to the swivel journal 17. The knife plate 21 is secured to the arm 20, as well as a lever 9, likewise secured to the arm 20. In addition to this, the upper nipper plate 14 is provided with an adjustable penetration comb 19, which keeps back those fibers of the fiber tuft 10, which do not feature the correct length of the detachment gap (the separation), from being drawn into the detaching rolls 6. The knife plate 21 is swivelled in the movement rhythm of the nipper head 3 against the cushion plate 16, or swivelled away from it. As a result, the nipper head 3 is open in the outer end position (as shown in FIG. 1), and is closed in the inner end position (in which the cushion plate 16 is furthest removed from the clamping point of the detaching roll 6), and clamps the fiber tuft 10 firmly. The synchronization of the movement of the upper nipper plate 14 with the movement of the nipper head 3 is effected by means of a linkage device, not shown, the ends of which are connected on the one hand to the machine stand 1 and, on the other, to the lever 9 which is secured to the nipper knife arm 20.
The detaching rolls 6 are formed by two pairs of detaching rolls 6', 6", each of which has a lower, driven detaching roll 23 and an upper detaching roll 24. Their periodic step-and-repeat, forwards and backwards (pilgrim step), movement has the effect, in forwards movement (as already mentioned) of conveying the combed web 11 in the direction of the arrow 25, and, in backwards movement, causes a piecing with the combed fiber tuft 10, which is delivered by the nipper head 3.
The drive for the comber machine is effected by means of a motor 31, which drives a timing shaft 33 by means of a reduction gear 32. With each revolution of the timing shaft 33, the machine completes one combing cycle. Likewise, in cycled synchronism with the timing shaft 33, the lower detaching rolls 23 are driven by means of a known design of step-and-repeat gear 37, in such a way that their forward and backward movements are effected in the same manner as on known comber machines during a combing cycle.
The detaching rolls 6 are rotatably mounted in bearings on a pillow block 41, and, as mentioned, are driven by the step-and-repeat gear 37. Alternatively, the drive system might employ a reversible electric motor (not shown). The pillow block 41 is mounted securely on a part 61 of the machine, which is connected to a lever 43 fixed in rotation by means of a swing shaft 42, mounted in bearings in the machine frame 1. By means of the application of a displacement of the lever 43, by the swivelling the shaft 42, the detaching rolls 6 are moved against the nipper head 3, or away from it, and the clamping line 44 of the inner pair of detaching rolls 6" is displaced along a circular track 45. This allows for the alteration of the ecartement E, which is the smallest distance between the clamping line 46 (the bite of cushion plate 13 and nipper knife plate 21) and the clamping line of the detaching rolls 6". This smallest value is obtained when the nipper 3 is at its most outward position, as shown in FIG. 1. FIG. 1 further shows, by the full lines, the detaching roll 6 in its closest possible position to the nipper head 3, this being the smallest separation E, for which the machine is designed. The dotted lines show the maximum value of the separation E. When the swivelling shaft 42 rotates counter-clockwise, the ecartement E increases up to a maximum value determined by the design of the machine, which can be limited by means of a stop, either fixed or movable, which limits the swivelling path of the shaft 42. The displacement or swivelling of the shaft 42 is created by means of a threaded spindle 47, rotatably mounted on bearings in the machine frame 1, which can be driven by hand or by means of a motor. Located on the threaded shaft of the spindle 47 is a nut 48, with an axle journal 49, on which one end of a linkage element 50 is connected. The other end of the linkage is connected to a swivelling journal 51 of the lever 43. The threaded spindle 47 and the lever 43 are parallel at the setting of the smallest separation value E, and the linkage element 50 is oriented at right angles to a central longitudinal axis of the lever 43. If the spindle 47 is rotated, the nut 48 is displaced upwards or downwards, and the shaft 42 swivels by means of the linkage 50 and the lever 43 about an angle, in which situation the detaching rolls 6 are moved into the position indicated by the dotted lines, and the ecartement E increases in either case.
The embodiment shows the axes of the detaching rolls 6--irrespective of the other movements which they perform for the conveying and piecing of the wad--movable on an arc-shaped track 45. It is possible for the track 45 to create a travel path which is flatter, or in a straight line, or otherwise curved. In this case, the pillow block 41 would accordingly need to be mounted on a crank arm (instead of a swing lever), or in correspondingly shaped guide curves secured to the machinery frame 1. Likewise, the displacement movement for the detaching rolls 6 could be effected by a motor with an increment generator associated with it, instead of by hand. In addition, instead of the reduction for the adjustment movement shown, other mechanical reduction gears are suitable, in the same manner.
The driven detaching rolls 23 are each positioned in a coupled manner on shafts 52 and 53 respectively, which are freely rotatable in the pillow block 41. These shafts, 52 and 53 are further rotatably mounted in an intermediate gearbox housing 54 of an intermediate gear system 55, secured to the pillow block 41 (FIG. 2). The intermediate gear box 55 is the transmission system between the step-and-repeat gear system 37 and the shafts 52 and 53. Located in the intermediate gearbox housing 54 on each of the shafts 52, 53 are gear wheels, 56 and 57 respectively, of the same size. The two toothed wheels 56, 57 mesh with an intermediate gear wheel 58, mounted so as to be freely rotatable in the housing 54; this intermediate gear wheel meshes in turn with a gear wheel 59. The gear wheel 59 is mounted in a rotationally-resistant manner on a shaft 42', which passes through the housing 54, and is located co-axially in relation to the swivelling shaft 42, capable of being driven in a periodic backwards and forwards movement by the step-and-repeat gear system 37. The intermediate gear housing 54 is swingably mounted so as to be capable of swivelling on the shaft 42', or so as to swivel on the machine frame about the axis of the shafts, 42 respectively 42'. When the ecartement value E is adjusted, the housing 54 is swivelled with the shafts 52, 53 and the gears 56, 57, 58 around the axis of the shaft 42'. The gears 56, 57, 58, 59 remain thereby in mutual engagement all the time, with the result that the adjustment can be made with the machine running. Instead of the gear wheel drive shown, a chain drive or similar arrangement can also be used instead of an intermediate gear 55.
While, with the embodiment described above, the nipper axis 2 represents a fixed bearing for the movable nipper head 3, in relation to which the bearing 41 of the detaching rolls 6 can be adjusted, in the case the comber machine described in the aforementioned UK-Patent 1 207 441, a fixed bearing 2' of this type is provided for the nipper head 3, which moves upwards and downwards in the direction of the double arrow 60 (FIG. 3). The degree of adjustability of the detaching rolls, according to the invention, is also effected with such a machine, in relation to this fixed bearing, inasmuch as the detaching rolls 6 can be moved and adjusted with the pillow block 41, relative to the oscillating link 61 which is suspended about their stroke path. | A comber machine with a nipper head (3) has a fixed bearing (2), and at least one pair of detaching rolls (6") which are rotatably mounted in bearings (41). The nipper head (3) and the detaching rolls (6") are moved during a combing cycle towards one another and away from one another by the distance of a stroke path, up to a minimum distance which corresponds to a predetermined separation value. While still maintaining the stroke path, the predetermined separation distance (ecartement value) can be adjusted. To facilitate the setting of the ecartement value, provision is made for bearings (41) of the detaching rolls (6") to be displaced relative to the fixed bearing (2) of the nipper head (3), jointly on a track (45) which enlarges or reduces the separation value. | 3 |
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims priority of U.S. Provisional Patent. Application Ser. No. 60/091,742, filed Jul. 6, 1998.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
N/A
BACKGROUND OF THE INVENTION
The present invention relates in general to a musical instrument transducer. More particularly, it relates to a piezoelectric transducer used with a stringed musical instrument such as a guitar.
The prior art shows a variety of electromechanical transducers employed with musical instruments, particularly guitars. Many of these transducers are not completely effective in faithfully converting mechanical movements or vibrations into electrical output signals which precisely correspond to the character of the input vibrations. This lack of fidelity is primarily due to the nature of the mechanical coupling between the driving vibrating member (i.e. a string) and the piezoelectric material of the transducer. Some of the prior art structures, such as those shown in U.S. Pat. Nos. 4,491,051 and 4,975,616, are also quite complex in construction and become quite expensive to fabricate. Furthermore, a transducer using a piezoelectric material requires a conductive layer, a ground layer, and some form of shielding to prevent electrical interference. These multiple layers not only increase the complexity of the transducer, but interfere with the ability to attach leads to the transducer as it is made smaller to operate in a musical instrument.
Differently shaped transducers have been produced for musical instruments. Generally, transducers for stringed instruments have a flat, elongated shape. The piezoelectric layer for such transducers can also be elongated, or can be individual crystals between electrodes. Alternatively, one prior art transducer was coaxially arranged, with a center electrode, surrounding piezoelectric layer, and outer electrode, as illustrated in U.S. Pat. No. 4,378,721.
Each shape offers unique difficulties in construction and varying degrees of quality in operation and performance. For good performance, the piezoelectric layer needs to respond to small string movements at a variety of frequencies. With a thicker layer of piezoelectric material, the material needs to be more flexible; if made too thick, the piezoelectric layer may be too brittle for the intended use, and may not provide satisfactory response characteristics across of range of input stimuli including the smallest string movements. To achieve sufficient resilience in a coaxial arrangement, U.S. Pat. No. 4,378,721 discloses a material formed from a rubber material mixed with a powdered piezoelectric ceramic and a vulcanizing or cross-linking agent. Piezoelectric ceramic is typically brittle and inflexible. This reference relies upon a rubber matrix to bind together the powdered ceramic material The use of a rubber material results in a significantly thicker piezoelectric material layer, which is inconsistently responsive across a variety of input frequencies; the rubber matrix tends to damp input stimuli, resulting in degraded response. A thicker piezoelectric layer, even if comprised of rubber, becomes more difficult to physically accommodate, to bend or to otherwise manipulate. Over time, it has been found that the composite piezoelectric layer such as described in this reference tends to deform in response to compression such as is typical in a stringed instrument application.
A further disadvantage of the coaxial transducer as described in U.S. Pat. No. 4,378,721 relates to its formation through a casting or molding process, such that the length of the resulting transducer is dependent on the size of the molds available. Other manufacturing processes are not suitable for the composite piezoelectric material due to a low degree of cohesiveness.
Additionally, the polarization of the piezoelectric material so of this reference must be performed after completion of the casting procedure. Two opposing, plate-like electrodes, on either side of the transducer, are used to initialize the magnetic domains of the piezoelectric material, thereby complicating and extending the manufacturing process of such a transducer. Therefore, a need exists for an accurate, responsive transducer with a thin, relatively stiff piezoelectric layer which can be economically formed into a coaxial arrangement.
BRIEF SUMMARY OF THE INVENTION
The deficiencies of the prior art are substantially overcome by the transducer according to the present invention, which includes a coaxial structure having a central conductor, a piezoelectric polymer layer, and an outer conductor. The central conductor may be formed of a wire bundle or a solid wire. A piezoelectric cylinder of either a piezoelectric copolymer or a monopolymer is formed about the central conductor. The piezoelectric material may be substantially thinner than that of the prior art, thus providing significantly improved response characteristics for the output signal, while providing a desired degree of flexibility and resistance to deformation over time.
The outer conductor can be formed as a braided sheath or simply as a conductive paint on the outside of the piezoelectric material. Other embodiments include the use of conductive foil, conductive shrink tubing, or any other flexible, conductive material which has a minimal impact on the flexibility of the overall transducer and on the response characteristics of the piezoelectric material. An additional mechanically shielding layer may also be provided, though this layer must not significantly interfere with the responsiveness of the transducer. Leads are attached to the central and outer conductors in order to complete the transducer. The coaxial transducer may be provided with a length sufficient to fit within the saddle of a guitar, underneath the strings. Other embodiments may be configured for use with other stringed musical instruments.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
This invention is pointed out with particularity in the appended claims. The above and further advantages may be more fully understood by referring to the following description and accompanying drawings, of which:
FIG. 1 is a perspective view of a stringed musical instrument, in particular guitar, that has incorporated therein the transducer of the present invention;
FIG. 2 is a cross-sectional view taken along by 2 — 2 of FIG. 1;
FIG. 3 is a cross-sectional view taken along line 3 — 3 of FIG. 1;
FIG. 4 is a cut-away view of the structure of the transducer according to the present invention; and
FIG. 5 illustrates a procedure for fabricating a transducer according to the present disclosure.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 illustrates a guitar that is comprised of a guitar body 110 having a neck 112 and supporting a plurality of strings 114 . In the embodiment disclosed herein, as illustrated in FIG. 3, there are six strings 114 . The strings 114 are supported at the neck end of the instrument (not shown). At the body end of the strings, the support is provided by a bridge 116 . The bridge 116 includes a mechanism, such as illustrated in FIG. 2, for securing the end 117 of each of the strings 114 . The bridge 116 is slotted, such as illustrated in FIG. 2, in order to receive a saddle at 118 . The strings 114 are received in notches in the saddle 118 at the top surface.
FIGS. 2 and 3 illustrate cross-sectional views of the bridge and saddle with the positioning of the transducer of the present invention. The transducer 120 is positioned within the bridge underneath the saddle. As illustrated in FIG. 3, the transducer extends below the entire saddle underneath each of the strings of the instrument. In one embodiment, a portion of the transducer, when fully installed under the saddle, is bent towards and into the interior of the instrument, where conductive leads are attached for communicating the output signal to appropriate signal conditioning and/or amplifying circuitry (not shown). In this embodiment, installation of the transducer is achieved by feeding a free end of the transducer, opposite the conductive leads, into an opening in the interior of the guitar, beneath the bridge, until the transducer extends under the length of the saddle.
The structure of the transducer is illustrated in FIG. 4 . The transducer of the present invention is formed of an inner conductor 210 , a piezoelectric polymer layer 220 , and outer conductive layer 230 . The inner conductor in the illustrated embodiment is formed of a conductive material having cylindrical or substantially cylindrical shape. It may be a single wire (not shown) or a twisted bundle of a plurality of individual wires 211 . Such a bundle may further include non-conductive elements (not shown) useful for increasing the volume or rigidity of the inner conductive core 210 ; while it is preferable that the transducer of the present invention be sufficiently flexible that it can easily conform to irregular surfaces under the saddle and can be bent for facilitating installation within a bridge, it may also be useful for the transducer to exhibit a degree of mechanical rigidity as well. According to one embodiment, the inner conductor 210 has a diameter of approximately 0.075 to 0.080 inches.
A layer of a piezoelectric polymer material 220 is formed about the inner conductor 210 . In one embodiment, the piezoelectric material is formed to have a thickness less than the diameter of the central conductor. In particular, a further embodiment provides the piezoelectric material having a thickness less than half the diameter of the inner conductor. According to a specific variant of this embodiment, the piezoelectric material has a thickness between approximately 0.010 and 0.015 inches. However, in other embodiments, central conductors are employed which are of such dimensions that the piezoelectric layer is as large as or larger than that of the central conductor.
The piezoelectric material is more accurately termed a piezoelectric polymer. The material is an amorphous structure containing many thousand individual crystals, which is constructed by combining different polymeric elements and subjecting them to high temperatures. This forms a fused material containing thousands of crystals. The piezoelectric polymer used in this invention may be a polyvinylidene fluoride (PVDF) copolymer. Alternatively, it may be a PVDF homopolymer. PVDF homopolymers are described in U.S. Pat. No. 4,975,616. PVDF copolymers can include, but are not limited to, vinylidene/tetrafluorethylene and vinylidene/trifluoroethylene polymers. The use of a thin layer of a piezoelectric polymer with a stiffer conductor provides the desired resilience for acceptable outputs from the transducer in a musical instrument and a desired, even responsiveness to a broad range of input frequencies without mechanical loss due to damping. The piezoelectric polymer is sufficiently resilient to offer the desired flexibility without the need for a rubberized matrix, and is resistant to compressive forces over time, such that the original transducer shape is maintained. Polymer materials as used in the presently disclosed transducers also tend to resist becoming brittle over time.
Around the piezoelectric polymer material, an outer conductive layer 230 is formed. The outer conductor 230 may be a braided sheath of wires. Alternatively, the outer conductor may simply be a conductive paint applied to the outer surface of the piezoelectric material. Further embodiments include the use of other flexible, conductive materials, including conductive foil, conductive shrink tubing, or other similar materials. The outer conductor 230 also forms a shield about the transducer. Conductive leads (not shown) are attached to the inner conductor 210 and the outer conductor 230 for providing signals from the transducer. The manner of attaching these leads can be according to state of the art practices with respect to coaxial cables outside the field of transducers. The conductive leads are preferably shielded to avoid the introduction of noise.
With reference to FIG. 5, a transducer according to one embodiment of the present disclosure is fabricated according to the following procedure. An electrically conductive central core is provided. Extrusion tools as known to one skilled in the art are employed in forming the piezoelectric polymer material layer about the central core. As part of the same process, the outer conductive layer is formed about the piezoelectric layer. The exact process for application of the outer layer depends upon the material chosen: conductive paint may be sprayed; conductive foil may be wrapped; conductive mesh may be woven.
As part of the extrusion process for this transducer, electrodes may be provided to polarize the piezoelectric polymer material as it is extruded. For instance, exposure to a DC field results in substantial alignment of the magnetic domains within the piezoelectric material. Once so aligned, the piezoelectric material is capable of generating a detectable potential when subject to the stresses to be monitored, in this case, the vibration of strings on a guitar or other musical instrument. Thus, a transducer according to the present disclosure may be fabricated to any length desired and simultaneously polarized, eliminating waste and simplifying the manufacturing process. The exact order of the steps of FIG. 5 may be rearranged in order to accommodate preferred manufacturing practices.
In alternative embodiments of the present disclosure, the cross-section of the resulting transducer is not perfectly round, but may be symmetrically or asymmetrically ovoid. Further, one or more sides of the transducer cross-section may be flat. For instance, the transducer assembly may have a rectangular cross-section. The choice of cross-sectional configuration may depend upon the environment into which the transducer is to be installed and any apertures through which the transducer must pass in order to reach its operating position. It is preferred in one embodiment that the central conductor have a diameter or thickness which is greater than the maximum thickness of the surrounding piezoelectric layer, regardless of cross-sectional configuration. Appropriate extrusion tooling is employed for these various configurations. Flexibility in determining transducer length through an extrusion process is maintained.
Further layers may be incorporated into the transducer as presently disclosed. For instance, it may be desirable to incorporate a mechanical shielding layer over the outer conductive layer. However, care must be exercised in selecting a shield material which protects the outer conductor without compromising the responsiveness of the piezoelectric material.
Having described at least one embodiment, it should now be apparent to those skilled in the art that numerous other modifications and changes can apply to this invention. Specifically, variations in the dimensions listed herein are contemplated. Additionally, while a transducer according to the present invention has been described for use with an acoustic guitar, the transducer may be utilized with other stringed instruments such as, without limitation, violas, pianos, or electric guitars. Such modifications and changes are contemplated as falling within the scope of the invention, which is limited solely by the pending claims. | A transducer for a stringed musical instrument utilizes a coaxial structure. A thin layer of a piezoelectric polymer material is extruded about an inner, electrically conductive core. An outer conductor is formed about the piezoelectric polymer material. Polarization of the piezoelectric polymer material is accomplished in conjunction with the extrusion process. The piezoelectric polymer material has an optimized thickness for consistent responsiveness across a desired range of input stimuli, and is capable of maintaining the integrity of the transducer over time. The transducer configured for placement underneath the saddle in a bridge of a stringed musical instrument. | 8 |
This application claims the benefit of U.S. Provisional Application No. 60/293,614 filed on May 29, 2001.
FIELD OF THE INVENTION
The disclosed device relates to transmissions for motorized vehicles. More particularly it relates to a device which functions as a transmission which is coupled at an input end to power sources such as an internal combustion or turbine engine and transmits the energy from that power source to drive wheels or prop or other propulsion component of a vehicle varying the amount of torque and speed delivered the engine to fit the immediate requirements of the vehicle. The disclosed device could additionally function as a brake for vehicles when configured differently by attaching the output shaft to a generator or other device doing work, or to a fixed position on the frame of the vehicle, and the input shaft to the drive shaft or other shaft that communicates with the wheels of the vehicle to be slowed.
BACKGROUND OF THE INVENTION
Engine driven vehicles such as automobiles, buses, tractors, boats, and similar vehicles, conventionally use a transmission to communicate power and torque developed by the engine, to the wheels or drive of the vehicle. Additionally, helicopters and boats are frequently in need of changing the nature of the power transmitted from the engine to the propulsion components powering them varying both the torque and speed to a varying requirement. Early vehicles and current industrial vehicles frequently use a manual transmission which contains a series of different gears which may be interrelated to take input power from the engine and output that power to the wheels with sufficient torque and speed for the vehicle while maintaining the engine at optimum speed to operate.
Automatic transmissions operate to provide the same communication of variable torque and speed to the rear wheels only they do not require manual manipulation by the user nor a clutch to disengage the transmission during gear changes. Just like that of a manual transmission, the automatic transmission's primary job is to allow the engine to operate in its narrow range of speeds while providing a wide range of output speeds and torque to the drive wheels with which it communicates engine power. Without a transmission, vehicles would therefor be limited to one gear ratio and that ratio would have to be selected to allow the car to travel at the desired top speed. Such an arrangement would provide a vehicle with little acceleration when starting out, and, at high speeds, the engine would be nearing it maximum revolutions.
The key difference between a manual and an automatic transmission is that the manual transmission locks and unlocks different sets of gears to the output shaft to achieve the various gear ratios, while in an automatic transmission the same set of gears produces all of the different gear ratios. The planetary gearset in the automatic is the device that makes this possible in an automatic transmission. However, planetary gearsets, bands that lock parts of a gearset, and wet clutches that lock other parts of the gear set are prone to failure and slippage. Further, and incredibly complicated hydraulic control system is required to control the clutches and bands and gear sets of a conventional automatic transmission lending more potential problems to long term reliability in such devices.
As such, there is a pressing need for a transmission which will automatically vary the amount of torque and speed communicated to the wheels of a vehicle from the engine. Such a transmission should have few moving parts and systems to help insure reliability and ease of maintenance. Such a device should provide the optimum torque and speed to the wheels from the engine while allowing the engine to rotate and operate at its optimum performance speed.
SUMMARY OF THE INVENTION
The above problems and others are overcome by the herein disclosed constant velocity transmission which provides maximum torque and speed from the engine to the output shaft and the communicating drive component such as wheels on a vehicle, while maintaining the engine at optimum operational speed. The device herein disclosed and described features a minimum of moving parts and control systems to enhance reliability and performance over conventional automatic transmissions which as noted require a plethora of parts and complicated hydraulic operating and control systems.
The herein disclosed and described constant velocity transmission takes advantage of the principle of fluid friction to transmit rotational forces providing torque and speed to the output shaft from rotating input shaft communicating with the drive motor. Rotating freely or inside of an appropriate housing, the device develops fluid friction between the major components thereby communicating power from the input shaft, connected to the driving motor to an output shaft which rotates in direct correlation to the motor speed. This fluid friction transfers energy communicated from the rotating motor to the output shaft by way of the fluid friction that develops in the layers of fluid moving in the housing in relation to the input shaft velocity. Initially fluid friction is substantially zero until vanes about the circumference of the inside rotating cone shaped drive cone, laterally translate upon the sloped outer surface of the drive cone and move outward toward the inner ribbed surface of the outer drum. As they move closer to inside surface of the outer drive drum, the vanes increase the fluid friction on the inner ribbed surface thereby exerting more pressure on the outer drum and moving it in the direction of rotation. This fluid friction increases proportionally as the vanes move closer to the driven drum and decreases proportionally as the vanes laterally translate on the drive cone and move away from the driven drum.
This device will function using any number of different viscosity fluids for fluid friction communication, from conventional transmission oil to water with near equal efficiency since the determining factor is the distance between the translating vanes and the inner surface of the driven drum. In the case of watercraft, the water in which the boat itself moves might be used as the fluid for the device and provide additional benefits from an in exhaustive source and inherent cooling from such a large reservoir.
This device features a front input shaft communicating power from the drive engine to a drive cone, supported on the input shaft inside of a driven drum which in turn communicates power to an output shaft via the aforementioned fluid friction. The input shaft is appropriately supported by bearings and communicates this support to the drive cone. The driven drum acts as a housing for the components which serve to operate the assembled device and is filled with a working fluid such as hydraulic oil.
The drive cone which is housed internally in the driven drum has slidable drive vanes along its circumference which laterally translate about the center axis of the drive cone. This lateral translation of the drive vanes on the slope or incline of the drive cone frustro-conical shaped exterior causes the distal edges of the drive vanes to move closer to or further away from the vaned interior surface of the driven drum. As the translating drive vanes move outward closer to the inside vaned surface of the driven drum, the working fluid builds up fluid friction between the different layers of fluid moving at different velocities. This fluid friction rotates the output drum with a force that is in relation to the distance between the drive cone mounted vanes and the stater vanes formed on the surface of the drive strum. The smaller the distance, the greater the fluid friction and the consequential greater applied torque. Conversely, the greater the distance, the less applied torque.
The operation of the device herein disclosed and described is dependent on a working fluid, in this case, light weight oil such as conventional transmission oil. While some of the fluid remains internal inside the driven drum assembly, in the current best mode a reservoir of additional working fluid is stored in an external reservoir until the input shaft is rotated by an external power source such as a conventional gasoline or diesel engine. The input shaft has splines similar in shape to those of a hydraulic pump rotor and rotate inside a pump housing thereby providing pump operation as the shaft rotates. This pumping action provides the means to pressurize the operating fluid of the device during use.
The input shaft which communicates rotational power from the attached motor, supported by conventional bearings appropriately positioned in the outer housing supports the driven drum. The input shaft terminates into a bearing at the rear of the driven drum at an end plate which is attached to the output shaft which communicates power from the motor to the wheels or other device being powered. This arrangement thus allows the input shaft to rotate the drive cone located inside the driven drum, independently of the driven drum assembly with the communicating motor driving the input shaft and the driven drum driving the output shaft. Fluid friction transfers rotational energy from the drive cone and translating vanes thereon to the driven drum. The fluid friction intensity is inversely proportional to the distance between the movable drive vanes and the driven drum stator vanes. The smaller this distance, the larger the fluid friction.
Lateral translation of the vanes along the center axis of the drive cone about the slanted exterior surface is provided by a controllable pressure actuator plate. The pressure actuator plate acts to press upon the rear surface of the vanes and translate them up the ramps on the frustro-conical drive cone. A biasing means such as a spring acts on one end of the pressure actuator to move it rearward while a second controllable biasing means such a hydraulic pressure acts on the other end of the pressure actuator to move it toward the drive cone. By increasing the pressure acting to move the pressure actuator toward the drive cone, the reverse pressure from the rearward biasing means is overcome. Conversely, by decreasing the pressure of the second controllable biasing means, the bias provided by the rearward biasing means overcomes that of the controllable biasing means thereby moving the controllable pressure actuator plate away from the drive cone and allowing the vans to translate to a lower position on the drive cone and further away from the stator vanes of the driven drum. In this fashion, the torque from the input shaft communicated to the output shaft from the driven drum may be easily and accurately controlled to an infinite number of settings rendering the device infinitely variable in its ability to adjust the torque communicated to the output shaft.
As noted above, the device as herein described and disclosed could not only provide an infinitely variable transmission for a vehicle, but also a means to brake the speed of the vehicle by hooking the device to communicate with the rotating wheels on one end, and a fixed position on the vehicle or to a generator or pump on the output end to brake the vehicle by doing work.
Accordingly, it is the object of this invention claimed herein to provide a simplified automatic transmission device to transmit power from a power plant at varying amounts of torque and speed to the component being driven by the power plant.
It is another object of this invention to supply an automatic transmission for a vehicle to transmit power from the engine to the wheels at optimum levels of torque for the moment while concurrently maintaining engine speed at optimum levels.
It is still another object of this invention to supply a device which can also function as a brake for a vehicle by providing resistance to the rotation supplied from the output shaft to the device.
Further objectives of this invention will be brought out in the following part of the specification, wherein detailed description is for the purpose of fully disclosing the invention without placing limitations thereon.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
The accompanying drawings which are incorporated in and form a part of this specification illustrate embodiments of the disclosed processing system and together with the description, serve to explain the principles of the invention.
FIG. 1 is a cut away view of the device showing the components in configured for idle.
FIG. 2 is a cut away view of the device showing the components engaged to transmit maximum torque.
FIG. 3 is an exploded view of the components of the disclosed device.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The device 10 herein disclosed functions using fluid friction to transmit rotational force from an input shaft 12 having a center axis 13 therethrough, communicating with a power source such as an internal combustion engine, a turbine engine, a jet engine, or similar means for power generation, to an output shaft 14 which is connected to the component to be driven or powered by the disclosed device 10 . Generally drive wheels, propellers, flywheels, generators or any such components which require varied torque from the power source during their operation will benefit from using the disclosed device. As is obvious to those skilled in the art the components which use power from an engine or other source named herein are not all inclusive and use of the device 10 herein disclosed to communicate power to any component with varying torque requirements and speeds is anticipated. The various components of the disclosed device 10 may operate inside of an appropriate optional exterior housing 15 , or may be self housed due to the configuration of the assembled device 10 allowing such. In operation, power communicated from the motor or engine or other means for power generation used in combination herewith is communicated to the input shaft 12 . A drive cone 16 is attached to the input shaft 12 and the drive cone 16 center axis is essentially the center axis 13 of the input shaft. The drive cone 16 which is frustro conical in exterior dimension, has a sloped exterior surface 18 which has a diameter widest at the end closest to the drive input shaft 12 and is narrowest at the opposite end closest to the output shaft 14 .
A plurality of drive vanes 20 are attached to the sloped surface 18 of the drive cone 16 in line with the center axis 13 and substantially equidistantly spaced from each other. The drive vanes 20 are attached to allow them to laterally translate on the sloped surface 18 of the drive cone 16 from a retracted position of FIG. 1 to an extended position as shown in FIG. 2 . The drive vanes 20 have an attachment edge 22 configured for cooperative engagement with the sloped surface 18 of the drive cone 16 such that they will laterally translate thereon. The distal edge 24 of the drive vanes 20 , opposite the attachment edge 22 , in the current best mode is angled in relation to the angle of the attachment edge 22 , such that the distal edge 22 is substantially parallel with the center axis 13 of the input shaft.
Also mounted to the input shaft 12 is a pressure plate 26 which is configured for slideable engagement on the input shaft 12 to translate from rearward position wherein the drive vanes 20 have their distal edge 24 closest to the center axis 13 to a forward position toward the front of the input shaft 12 wherein the pressure plate 26 would press upon the rear edge 28 of the laterally translate drive vanes 20 thereby moving them to their extended position which places the distal edge 24 of the drive vanes 20 to their position furthest away from the center axis 13 and closest to the interior surface 38 of the driven drum 30 .
Attached about the output shaft 14 either directly or using spacer 17 is the driven drum 30 which in the current best embodiment is supported for rotational movement about the center axis 13 by an end plate 32 which attaches to the front end of the output shaft 14 and a front plate 34 attached about the input shaft 12 . The center axis 13 extends through the center axis of the driven drum to the center axis of the output shaft such that all are inline.
The internal or rear end 36 of the input shaft 12 is in a sealed relationship with the end plate 32 which has a conventional bearing 35 therein to allow rotation of the input shaft 12 in this engagement supported by the end plate 32 ; however other bearing arrangements could be used and are anticipated. A similar mounting arrangement allows the front plate 34 to be in a sealed engagement with the input shaft 12 and mounted thereon using a conventional bearing 35 or other similar device and a seal to allow the input shaft 12 to spin in its sealed engagement with the front plate 34 . As is obvious to those skilled in the art, many bearing and seal relationships would allow the end plate 32 a sealed rotational engagement on the rear end 36 of the input shaft 12 and the front plate 34 to function with a sealed rotational engagement on the input shaft 12 and such are anticipated.
As can be seen, the front plate 34 and driven drum 30 and end plate 32 function to form a sealed housing for the drive cone 16 and drive vanes 20 and pressure plate 26 and the other components and working fluid inside the sealed housing so formed.
Formed on, or attached to, the interior surface 38 of the driven drum 30 are a plurality of stater vanes 40 substantially equidistant from each other in their position on the interior surface 38 of the driven drum 30 . In operation, the power source would communicate rotational power to the input shaft 12 which rotates the attached drive cone 16 . The drive vanes 20 which are laterally translateable in their mount to the drive cone 16 may be slid in their attachment on the exterior of the drive cone 16 to an infinite number of positions between those two points thereby allowing for an infinite number of positions of the distal edges 24 of the drive vanes 20 between their closest position to the interior surface 38 and their closest position to the center axis 13 thereby providing a means for lateral translation of the distal ends 24 of the drive vanes 20 toward and away from the center axis 13 . Of course other such means to laterally translate the distal ends 24 of the drive vanes 20 toward and away from the center axis might be used and are anticipated, such as the drive vanes 20 being retracted into the drive cone 16 and internal hydraulic force inside the drive cone 16 communicating with and moving the attachment ends 24 of the drive vanes 20 away from the center axis; however the current best mode of the device 10 features the lateral translation of the drive vanes 20 in their slideable engagement on the outside of the drive cone 16 .
Rotation of the input shaft 12 and attached drive cone 16 and drive vanes 20 submersed in the operating fluid of the device 10 , from the power communicated from the power source, develops fluid friction in direct correlation to the motor speed. This fluid friction transfers energy communicated from the rotating motor or similar power source, to the output shaft 14 by way of the fluid friction that develops in the layers of fluid moving in the housing formed by the driven drum 30 and endplate 32 and front plate 34 which is in relation to the input shaft 14 velocity.
Initially fluid friction is substantially zero until the drive vanes 20 about the drive cone 16 , are laterally translated upon the sloped outer surface 18 of the drive cone 16 by the pressure plate 26 moving from the rearward position toward the forward position. As the pressure plate 26 moves toward the forward position, the drive vanes 20 slide on the sloped surface 18 and their distal edges 24 move outward away from the center axis 13 and toward the inner ribbed surface formed by the stater vanes 40 on the inner surface 38 of the driven drum 30 . As the distal edges 24 move closer to the stater vanes 40 , they cause an increase of the fluid friction on stater vanes 40 on the interior surface 38 thereby exerting pressure on the driven drum 30 and moving it in the direction of fluid rotation. The force generated by this fluid friction increases proportionally as the drive vanes 20 move closer to the interior surface 38 of the driven drum 30 and the force so generated decreases proportionally as the drive vanes 20 laterally translate on the drive cone 16 and cause the distal edges 24 to move away from the interior surface 38 of the driven drum 30 and closer to the center axis 13 . The force from the fluid friction thus rotates the driven drum 30 with a force that is in relation to the distance between the distal edges 24 of the drive vanes 20 and the stater vanes 40 formed or mounted on the surface of the driven drum 30 . The smaller the distance, the greater the fluid friction and the consequential greater applied torque force. Conversely, the greater this distance, the less the fluid friction and resulting applied torque. As noted, the device 10 will function using any number of different viscosity fluids for fluid friction communication, from conventional transmission oil to water with near equal efficiency since the determining factor is the distance between distal edges 24 of the translating drive vanes 20 and the stater vanes 40 on the interior surface 38 of the driven drum 40 .
A means to position or to laterally translate the pressure plate 26 between the rearward position and forward position, in the current best mode is provided by pressurizing the same fluid which is used to transmit power in the device 10 . As depicted, the input shaft 12 has a means to pressurize the fluid in the form of pump 39 attached to the input shaft 12 thereby providing pump operation to pressurize fluid as the input shaft 12 rotates.
This pressurized fluid is then communicated via conventional tubing 41 and fluid passages 42 in the input shaft 14 to different points of the device internally and returned via the tubing 41 to an external reservoir 44 which communicates the working fluid back to the pump 39 . In a simple embodiment for controlling the lateral translation of the pressure plate 26 , a means to bias the pressure plate between the rearward and forward position is provided by a first biasing means such as a spring 46 acts on one end of the pressure plate 26 to bias it toward the rearward position while the controllable second biasing means provided by the hydraulic pressure ducted to the opposite side of the pressure plate 26 acts on the other end of the pressure plate 26 as a means to bias it toward the forward position. Using a control means such as a valve 43 , by increasing the pressure acting to move the pressure plate 26 to the forward position, the rearward pressure from the first biasing means in the form of the spring 46 is overcome moving the pressure plate 26 forward. Using the control means to decrease the fluid pressure acting on the rear of the pressure plate 26 , the rearward bias provided by the spring 46 overcomes the decreased hydraulic pressure and translates the pressure plate 26 to the rearward position.
Another means to laterally translate the pressure plate 26 can be provided by using controllable hydraulic pressure imparted to both sides of the pressure plate at varied force levels. The working fluid, in this case, light weight oil is stored in the reservoir 44 and as the input shaft 12 spins the pump 39 operates to draw operating fluid from the reservoir operating intake ports of the pump 12 . Three fluid passages 42 are capable of communicating pressurized working fluid from the pump. A first hydraulic line L 4 is pressurized with low pressure and high fluid volume and supplies pressurized working fluid into formed fluid passages 42 in the input shaft 12 that exit at each of the drive vanes 20 and in cavities and other points throughout the device 10 to provide a continuous supply of cool working fluid throughout the device 10 as would be conventionally done with most mechanical devices needing lubrication and cooling. The fluid from the first hydraulic line L 4 also acts as the working fluid whose viscosity allows the drive vanes 20 , to react by way of the aforementioned fluid friction with the stater vanes 40 attached to the driven drum 30 .
Two other hydraulic lines, L 2 and L 3 , are pressurized in low volume but with high pressure through a valve assembly, (not specified), that can be either within the pump 39 or external, depending upon application. This valve assembly is interrelated between the on ports and has three positions with Line L 2 on or off, and Line L 3 being on. If turned to Line L 2 on position, the valve opens Line L 3 to the on position allowing the high pressure in Line L 3 to dissipate to the working fluid pressure of L 4 . When reversed, the valve operates in reverse for operation in the other direction. In other words, if L 2 is pressurized and L 3 is vented to the working fluid pressure at the same time. Finally, if L 3 is pressurized, L 2 is vented to the working fluid pressure at the same time.
Operating as a means to control power imparted from the input shaft 12 to the driven drum 30 when the valve assembly is turned to a position to increase the RPM of the driven drum 30 , it opens L 3 to fluid pressure from the pump 39 , and L 2 simultaneously goes to the vent position, (working fluid low pressure). The high pressure fluid flows along L 3 from the pump 39 into the front outer housing, through the machined opening of the input shaft 12 . Once in the input shaft this fluid pressure flows along the drilled orifice of L 3 , exiting into a chamber 52 formed by the outer circumference of the input shaft 12 and the inside surface 54 of the pressure plate 26 at its attachment about the input shaft 12 . These two mating surfaces are sealed at either end by O-Rings 56 or similar seals and thereby form a first hydraulic cylinder 58 that acts as a means to laterally translated the pressure plate 26 along the outside of the input shaft 12 .
As the hydraulic pressure in L 3 increases the pressure in the hydraulic cylinder 58 , moves the pressure plate 26 toward the forward position, the outside wall 60 of the pressure plate 26 , slides within a cooperating surface 62 formed in the drive cone 16 . The cooperating surfaces are sealed with seals such as O-Rings 56 and form a second hydraulic cylinder 64 that operates directly opposite the action of the first hydraulic cylinder 58 . Line L 2 , which connects the valve assembly to the second hydraulic cylinder 64 , is vented by the valve action to the working fluid pressure as Line L- 3 is pressurized.
As the valve assembly is turned to a position to increase the RPM, several things take place at once. Hydraulic pressure of Line L 3 is increased. Hydraulic pressure of Line L 2 is vented to working fluid. The pressure increase in the first hydraulic cylinder 58 , and corresponding pressure decrease in the second hydraulic cylinder 64 , overcomes the bias of the spring 46 , and the pressure plate 26 moves toward the forward position thereby causing the drive vanes 20 to laterally translate on the drive cone 16 and move closer to the stater vanes 40 in the aforementioned fashion. When the drive vanes 20 slide forward along channels machined into the outside diameter of the drive cone 16 in the current best mode, they are held in line by the outer cone segments 48 that bolt directly to the drive cone 16 and are machined to accept the retaining flange of the movable drive vanes 20 . As the drive vanes 20 slide forward in their machined groves they also move outward up the slope of the drive cone 16 , increasing their relative diameter in the aforementioned operation forming the fluid friction between the drive vanes 20 and stater vanes 40 transferring energy from the rotating drive cone 16 assembly to the driven drum 30 . This energy transfer moves the driven drum 30 in the direction of rotation as that of the drive cone 16 .
When the valve position is reversed, the drive cone 16 rotates with the drive vanes 20 in the full rearward position and the driven drum 30 slows to a stationary position because no fluid friction takes place between the driven drum 30 and the drive cone 16 because the outer surface of the drive cone is with the drive vanes 20 retracted is distanced too far from the stater vanes 40 to exert enough force on them to move the driven drum 30 .
Of course those skilled in the art will realize that other means to laterally translate the pressure plate 26 from its rearward position to the forward position and back, could be used such as solenoids, cables, etc. and such is anticipated. However the current best mode works using pressurized working fluid to act upon the pressure plate 26 and a control means such as a valve to control the positioning of the pressure plate 26 by controlling the transmitted fluid pressure thereto. The pressurized fluid either works as two hydraulic cylinders opposing each other, or as one hydraulic cylinder opposing another biasing means such as a spring 46 . As can be seen, using this means to control the position of the pressure plate 26 to an infinite number of positions between its rearward position and forward position, the torque from the input shaft 12 communicated to the output shaft 14 from the driven drum 30 may be easily and accurately controlled to an infinite number of positions of the pressure plate 26 between its forward position and rearward position, thus rendering the device 10 infinitely variable in its ability to adjust the torque communicated to the output shaft 14 .
Also shown in the drawings are other components of the device 10 in the form of a plurality of drive cone outer vane segments 48 which are attached about the drive cone 16 between the drive vanes 20 and in the current best mode provide reinforcement to the drive vanes 20 . These are fixed vanes 48 that remain in position during the translation of the pressure plate 26 and resulting translation of the drive vanes 20 . The rearward portion 50 of the vane segments 48 is shaped to cooperatively engage with slots formed in the pressure plate 26 and the register with those slots thereby allowing the translation of the pressure plate 26 from the rearward position to the forward position during adjustment of the output of the device 10 to the user requirements.
As noted above, the device herein disclosed is ideally suited as a transmission for a land vehicle or water vehicle. However, as also noted, the device 10 could also function as a brake for a wheeled vehicle by mechanically communicating the input shaft 12 with the wheels of a vehicle and having the output shaft communicate with a generator, pump, or to a flange attached to the vehicle frame. The output shaft 12 would thus do work with the pump or generator, or when attached to a fixed position, such as a fixture on a vehicle frame (not shown), the friction of the fluid inside the driven drum 30 would also provide resistance and thus braking to the vehicle.
While all of the fundamental characteristics and features of the present invention have been described herein, with reference to particular embodiments thereof, a latitude of modification, various changes and substitutions are intended in the foregoing disclosure and it will be apparent that in some instance, some features of the invention will be employed without a corresponding use of other features without departing from the scope of the invention as set forth. It should be understood that such substitutions, modifications, and variations may be made by those skilled in the art without departing from the spirit or scope of the invention. Consequently, all such modifications and variations are included within the scope of the invention as defined by the following claims. | A constant velocity transmission which provides maximum torque and speed from a power source such as an internal combustion engine to an output shaft of the transmission while maintaining the engine at optimum operational speed. The transmission takes advantage of the principle of fluid friction to transmit rotational forces from drive blades mounted on an input shaft to stater blades positioned on the inside of a drum encompassing one end of the input shaft and the drive blades. The drive blades slidably mounted on a slanted surface of a drive drum on the input shaft and move closer to and away from the stater blades when laterally translated. Fluid driven by the drive blades imparts varied force and torque to the stater blades depending on their distance therefrom thereby transmitting variable speed and torque to the output shaft attached to the drum. | 5 |
FIELD OF INVENTION
This invention concerns changing the temporal sample rate of a motion-image sequence and involves temporal interpolation of images. It is particularly applicable to frame-rate conversion from low frame rates where temporal interpolation is difficult.
BACKGROUND OF THE INVENTION
Conversion of motion-image sequences between different temporal sampling rates such as film frame-rates or video field-rates is well known and is frequently necessary. It is commonly used in television and video systems to convert material between different acquisition, storage and distribution formats. The conversion is usually done by FIR filters that create values for new pixels from a weighed sum of existing pixel values. Motion compensated processing is now often used, in which motion vectors are derived and used to calculate which of the existing input pixels are most likely to represent a particular interpolated output pixel.
The growth in digital cinematography and synergistic developments in the art of high-definition television have resulted in the increasing use of ‘film-like’ frame rates, such as 24 and 25 frames per second. Most development work on conversion has been based on the conversion of ‘television-like’ temporal sampling rates, such as 50 or 60 fields per second. Algorithms developed for these higher temporal sampling rates, especially motion-compensated conversion algorithms, have been found to be challenged by the higher inter-frame differences that occur at 24 frames per second. The current invention provides a novel method of overcoming this challenge.
European patent EP 0 775 421 describes a method of conversion between closely-spaced frame rates (i.e. where the difference between the temporal sampling rates is less than about 2 Hz). A temporal interpolation mode is combined with a synchronisation mode, in which input images are re-timed without any temporal interpolation of pixel values. The choice of mode is controlled by the relative temporal phase between the input and output images. The advantage of this technique is that most images are re-timed and any artefacts due to temporal interpolation are limited to short time periods (typically of the order of 500 ms) which occur regularly as the input to output temporal phase cycles. This technique does nothing to hide any artefacts that are produced in the temporal interpolation mode—the mode is selected only on the basis of temporal phase.
SUMMARY OF THE INVENTION
There is provided apparatus for changing the temporal sample rate of a motion-image sequence in which an input image sequence at an input rate is converted to an output image sequence at an output rate, the apparatus comprising a temporal interpolator; a buffer associated with the temporal interpolator; and a controller, wherein the controller is supplied with a measure of temporal interpolation confidence and a measure of buffer occupancy; and wherein the apparatus has an interpolation mode in which the output image sequence is formed by temporal interpolation between images of the input sequence; and a synchronisation mode in which the output image sequence is formed by re-timing images of the input sequence without temporal interpolation images; the controller being adapted to select the synchronisation mode when the measure of temporal interpolation confidence is low and the measure of buffer occupancy indicates that images can be retimed without dropping or repeating of images and to select the interpolation mode when the measure of temporal interpolation confidence is high or when the measure of buffer occupancy indicates that images cannot be retimed without dropping or repeating of images.
An exchange rate at which images are exchanged between the buffer and the temporal interpolator the apparatus may be variable and wherein the controller is further adapted in the interpolation mode in dependence upon the measure of temporal interpolation confidence and the measure of buffer occupancy, to vary said exchange rate to optimise the buffer occupancy for retiming of images without dropping or repeating of images in a subsequent synchronisation.
Where the temporal interpolation is motion compensated using motion vectors and in which the said temporal interpolation confidence measure may be derived from confidence in the motion vectors. Thus, the temporal interpolation confidence measure may derived from the height of a peak in a phase correlation surface; from a displaced-frame or displaced-field difference; or from a measure of the number of motion vectors that point from respective input image pixels to a particular temporally interpolated image pixel.
Alternatively, the measure of interpolation confidence is derived from analysis of the energy spectrum of the input image data.
There is further provided a temporal interpolation method for converting images of an input image sequence having an input image rate to images of an output image sequence having a different output image rate that operates in a temporal interpolation mode during a first portion of the said sequence and in a synchronisation mode for a second portion of the said sequence, the method using a FIFO buffer connected to a temporal interpolator for the exchange of images between the buffer and the temporal interpolator at a buffer image exchange rate; wherein during the said first portion the temporal interpolator provides temporally interpolated images that comprise the respective portion of the said output image sequence; during at least part of the said first portion the buffer image exchange rate is varied with respect to the input or output image rate; and during said second portion the buffer provides the respective portion of the said output image sequence comprising un-interpolated input frames synchronised to the output image rate.
Where an output of the FIFO buffer forms an input to the temporal interpolator, the buffer image exchange rate is varied with respect to the input image rate, preferably increased above the input image rate when the output rate is lower than the input rate and decreased below the input image rate output rate is higher than the input rate.
Where an output of the temporal interpolator forms an input to the FIFO buffer, the buffer image exchange rate is varied with respect to the output image rate, preferably increased above the output image rate when the output rate is higher than the input rate and decreased below the output image rate output rate is lower than the input rate.
There is further provided a method of changing the temporal sample rate of a motion-image sequence in which an input image sequence at an input rate is converted to an output image sequence at an output rate, the method including an interpolation mode in which the output image sequence is formed by temporal interpolation between images of the input sequence; and a synchronisation mode in which the output image sequence is formed by re-timing images of the input sequence without temporal interpolation images; the synchronisation mode being selected when temporal interpolation confidence is low and images can be retimed without dropping or repeating of images and the interpolation mode being selected when the measure of temporal interpolation confidence is high or when images cannot be retimed without dropping or repeating of images. Preferably, images are exchanged between the temporal interpolator and a buffer at an exchange rate which is varied in the interpolation mode to optimise the buffer occupancy for retiming of images without dropping or repeating of images in a subsequent synchronisation.
There is also provided a temporal interpolation system for converting an input image sequence at an input image timing to an output image sequence at a different output image timing, the system comprising a temporal interpolator controlled by an interpolation phase measure; an image buffer that is connected to a temporal interpolator; and an interpolation phase generator that derives a changing interpolation phase measure from comparison of input image timing and the output image timing; wherein the rate of change of the interpolation phase of the temporal interpolator is controlled in response to the fill level of the image buffer and a measure of the likelihood of interpolation artefacts.
The measure of the likelihood of interpolation artefacts may be derived from confidence in the motion vectors or may be derived from analysis of the energy spectrum of the input image sequence.
There is also provided a method and apparatus for changing the temporal sample rate of a motion-image sequence in which an input image sequence at an input rate is converted to an output image sequence at an output rate wherein first portions of the output image sequence are formed by temporal interpolation between images of the input sequence; and, second portions of the output image sequence are formed by re-timing images of the input sequence without temporal interpolation, wherein a measure of temporal interpolation confidence is derived from the content of input images and input images having a high confidence measure contribute to the said first portions; and input images having a low confidence measure contribute to the said second portions.
In a preferred embodiment the said temporal interpolation is motion compensated interpolation using motion vectors and the said motion vectors are derived by phase correlation.
Advantageously the said temporal interpolation confidence measure is derived from the height of a peak in a correlation surface.
In an alternative embodiment the said temporal interpolation confidence measure is derived from a displaced-frame or displaced-field difference.
BRIEF DESCRIPTION OF THE DRAWINGS
An example of the invention will now be described with reference to the drawings in which:
FIG. 1 shows a block diagram of a frame-rate conversion system according to an exemplary embodiment of the invention.
FIG. 2 shows a timing diagram that illustrates the operation of the system of FIG. 1 .
FIG. 3 shows a flow-chart of the control of the system of FIG. 1 where the output frame-rate is higher than the input frame-rate.
FIG. 4 shows a flow-chart of the control of the system of FIG. 1 where the output frame-rate is lower than the input frame-rate.
FIG. 5 shows a block diagram of a frame-rate conversion system according to a further exemplary embodiment of the invention.
FIG. 6 shows a block diagram of a frame-rate conversion system according to a further exemplary embodiment of the invention
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an example of a frame-rate conversion system according to an example of the invention. Temporal interpolation of frame rates is often combined with spatial interpolation, for example ‘spatio-temporal’ interpolation between interlaced and progressive scanning rasters. The invention is not relevant to spatial interpolation and so it will not be described here. The skilled person will appreciate how spatial interpolation is combined with temporal interpolation according for example to the known art of standards conversion and will be able to combine the novel temporal processing of the invention with known spatial interpolation.
Image data ( 1 ) is input to the system. This will typically be chrominance and luminance values for the pixels of a stream of temporal samples of a scene. For example the temporal samples may be television fields or film frames. In the description which follows, the input and output images will be referred to as ‘fields’ as would be the case in the conversion between interlaced television formats having different field rates. However, as the skilled person will appreciate, either the input or the output images may be film frames, or progressive (i.e. not interlaced) television frames, or any other representation of a temporal sample of a scene.
Timing information is extracted from the image data ( 1 ) by an input timing information separator ( 2 ) that outputs input image timing data ( 3 ) that defines the start time of each of the fields in the image data ( 1 ). The timing information separator ( 2 ) may be a decoder for timing reference signals included in the image data ( 1 ). An input temporal phase accumulator ( 4 ) is locked to the input image timing data ( 3 ) and produces an input temporal phase signal ( 5 ) that has a value of zero at the start of each input field and increases linearly until the start of the next input field, when it returns to zero.
Output reference timing information ( 6 ) is also input to the system; this information defines the required output field times and would typically be an output timing reference signal that identifies the required start time of each output field. The system of FIG. 1 derives a stream of temporally interpolated output images ( 7 ) comprising fields that are timed according to the output reference timing information ( 6 ).
The image data ( 1 ) is input to a known temporal interpolation system ( 8 ), which converts it to a stream of temporally interpolated fields ( 9 ). These interpolated fields are produced in response to an image request signal ( 10 ) and an interpolation phase signal ( 11 ). When an interpolated image is requested by the signal ( 10 ), the interpolation system ( 8 ) combines input fields ( 1 ) in known manner to derive an interpolated field ( 9 ) that has a temporal position between two input fields as defined by the interpolation phase signal ( 11 ).
The temporal interpolation system ( 8 ) outputs a ‘conversion confidence’ signal ( 12 ). This signal is a measure of the quality of the temporal interpolation, i.e. it is large when few interpolation artefacts are expected, and small when objectionable interpolation artefacts are expected. In a linear (i.e. non-motion-compensated) interpolator this measure could be related to the presence in the input fields of frequency components that are likely to be aliased by the temporal interpolation.
In a preferred embodiment of the invention the interpolation system ( 8 ) is a motion-compensated interpolator using motion vectors derived from phase correlation. It is well known to derive a measure of ‘motion vector confidence’ from the height of the peak in the correlation surface used to derive a motion vector. A suitable conversion confidence measure can be derived from a combination of the peak heights corresponding to the motion vectors used in the conversion. If peaks are high then confidence will be high. If motion vectors are derived by block matching then a combination of match errors, or displaced-frame, or displaced field, differences can be used to derive the conversion confidence measure. If the match errors or displaced-frame/displaced-field differences are low then the confidence will be high. The confidence measure will vary in dependence upon the content of the input fields and typically a new value will be generated for each input field.
Where the confidence derivation is part of a motion estimation process it is likely that this process will precede the actual motion-compensated interpolation process. Typically, adjacent input fields will first be compared to derive motion vectors, then these vectors will be associated with the pixels of these fields and then these vectors will be input to the interpolation process. Thus the confidence value for an interpolated output field will typically be available before that field is created.
A control system ( 13 ) responds to the conversion confidence signal ( 12 ) and alters the operation of the system when necessary, so as to avoid the output of fields showing interpolation artefacts; this will described in detail below.
First, assume that the conversion confidence signal ( 12 ) indicates that the confidence in the interpolation is high, and therefore few artefacts are expected in the interpolated fields ( 9 ). The output reference timing information ( 6 ) is routed via a switch ( 14 ) that is controlled by the control system ( 13 ), to an interpolation frame rate oscillator ( 15 ). This phase-locks to the signal from the switch ( 14 ) to produce the image request signal ( 10 ), which samples the input temporal phase signal ( 5 ) in a sampler ( 16 ). The sampled phase value represents the input phase that corresponds to the output field time defined by the output reference timing information ( 6 ). This forms the interpolation phase signal ( 11 ). Thus the timing of the interpolated fields ( 9 ) corresponds with the output reference timing information ( 6 ). These interpolated fields are input to a first-in-first-out buffer ( 17 ), whose output is controlled by the output reference timing information ( 6 ). Fields are output from this buffer at the required output timing, and these form the stream of temporally interpolated output images ( 7 ).
However, if the conversion confidence signal ( 12 ) indicates that the confidence in the interpolation by the interpolation system ( 8 ) is low, and therefore interpolation artefacts are likely to be present in the interpolated fields ( 9 ), then the control system ( 13 ) operates to change the setting of the switch ( 14 ) so that the interpolation frame rate oscillator ( 15 ) is locked to the input image timing data ( 3 ). This oscillator is now synchronised with the input temporal phase accumulator ( 4 ) (because they both have inputs from the input image timing data ( 3 )), and so the interpolation phase signal ( 11 ) from the sampler ( 16 ) is always zero. In other words the interpolation system ( 8 ) is instructed to produce output fields that are co-timed with its input fields. Typically the interpolation system ( 8 ) will pass through the input fields without any modification and no interpolation artefacts will be introduced.
These unmodified fields will not, of course, be timed according to the output reference timing information ( 6 ). However provided the buffer ( 17 ) contains some fields, they will be retimed by the buffer ( 17 ) to the required output timing. Clearly, if the required output rate as defined by the output reference timing information ( 6 ) is different from the input rate as defined by the input image timing data ( 3 ), the buffer ( 17 ) will either fill or empty, and is likely to under- or over-flow. This is avoided by changing the frequency of the frame rate oscillator ( 15 ) in response to a frequency control signal ( 18 ) from the control system ( 13 ). This will be further explained below.
The operation of the system of FIG. 1 is further illustrated by the timing diagram of FIG. 2 . This Figure shows an example of conversion from a sequence of input field times ( 20 ) to a higher field-rate sequence of output field times ( 21 ).
Initially (i.e. at the left of the Figure) the interpolation confidence is high and few interpolation artefacts are expected. The interpolation system ( 8 ) of FIG. 1 produces a stream of interpolated fields ( 22 ) that correspond with the output field times ( 21 ). The required interpolation phase for each output field is shown by the points of the graph ( 23 ). The interpolation phase values vary cyclically according the difference between the input and output field rates.
As previously explained, the interpolated fields are input to the buffer ( 17 ) of FIG. 1 as they are created, and output fields are taken from the buffer at the required output field times. At the left of FIG. 2 the interpolated field times ( 22 ) correspond with the output field times ( 21 ). The buffer thus holds a fixed number of fields and represents a fixed delay. This delay is shown in the graph ( 24 ) where it is assumed that some samples have previously been input to the buffer and there is a finite delay value as a result.
At time ( 25 ) the interpolation confidence falls, indicating that interpolated fields are likely to have artefacts. The control system ( 13 ) of FIG. 1 then instructs the interpolation system ( 8 ) to pass the input fields at their original times without interpolation. The interpolated field times ( 22 ) now correspond to the input field times ( 20 ), and the corresponding interpolation phase values ( 23 ) are all zero. As the output field rate is higher than the input field rate the buffer ( 17 ) of FIG. 1 empties, with consequent reduction in its delay, as shown by the graph ( 24 ).
At time ( 26 ) the buffer is almost empty, and the corresponding delay approaches zero. In order to avoid the temporal discontinuity in output field times that would occur if the buffer under-flowed, the control system reverts to the interpolation of fields at the output field rate. The interpolation phase values ( 23 ) now follow the phase difference between the output field times ( 21 ) and the input field times ( 20 ). And, the buffer delay ( 24 ) remains constant at a low value.
Clearly it would be advantageous to fill the buffer so that interpolation artefacts in future output fields can be avoided. This can be done by increasing the field rate of the interpolated fields ( 22 ) above the field rate of the output fields ( 24 ). However, this increased rate is another potential source of artefacts and it has been found preferable only to do this when the interpolation confidence is high. At time ( 27 ) the confidence returns to a high value and the control system increases the rate of the frame rate oscillator ( 15 ) of FIG. 1 above the rate of the output fields ( 21 ). The interpolation phase values ( 23 ) now cycle at the difference between the input field rate and the (artificially high) interpolated field rate. And, the buffer delay ( 24 ) increases steadily.
At time ( 28 ) the buffer level is sufficiently high to provide un-interpolated output fields during periods of low confidence, and so the control system returns the frequency of the frame rate oscillator ( 15 ) of FIG. 1 to the frequency of the output fields ( 21 ). Provided the confidence remains high, fields are interpolated and input to the buffer at the required output rate and the buffer delay remains constant at its high value. If the confidence falls, the system returns to its ‘synchronisation’ mode so as to avoid interpolation artefacts.
An example of suitable control logic to achieve these operations is shown in the flow diagram of FIG. 3 . At step ( 31 ) fields are interpolated at the required output rate. At step ( 32 ) the buffer level is tested against a high threshold to see if is high enough to support expected periods of low confidence. If the level is below the high threshold, the confidence is tested at step ( 33 ), and if it is high, the rate of interpolation of fields is increased higher than the output field rate at step ( 34 ). If the confidence was low at step ( 33 ) the system waits for high confidence before proceeding to step ( 34 ).
After changing to the high interpolated field rate at step ( 34 ), the process returns to step ( 32 ). Once the buffer level is above the high threshold, the test of step ( 32 ) directs the process to test the confidence at step ( 35 ). If it is high, the processing is returned to step ( 31 ) where the rate of the interpolated fields is returned to the required output rate.
If the confidence is low at step ( 35 ) the interpolation phase is tested at step ( 36 ) to see if it is close to zero. If the confidence is low, and the interpolation phase is close to zero, step ( 37 ) changes the operation of the interpolator so that input fields are passed to the buffer at the input field rate without interpolation. This mode of operation is only initiated when the interpolation phase is close to zero so as to avoid a sharp discontinuity in the phase, which could be perceived as an artefact.
Once the system has been put into the ‘synchronisation’ mode at step ( 37 ), the buffer level is tested at step ( 38 ) to see if it is above a low threshold; and, if it is, the confidence is tested at step ( 39 ) to see if it is still low. If there is a danger that the buffer may under-flow, or the confidence returns to a high level, then the process returns to step ( 31 ), which restores conventional temporal interpolation from the input field rate to the output field rate.
So far, the required output rate has been assumed to be faster than the input rate. The invention is equally applicable to the case where the required output rate is slower than the input rate, and the system of FIG. 1 equally applicable. In this case the buffer fills when input fields are passed to the buffer without interpolation. When the interpolation confidence is high the buffer level (i.e. the buffer delay) should ideally be low, so as to be ready for the buffer to fill if confidence falls. The buffer is emptied by interpolating at a rate lower than required output rate. This is achieved in the system of FIG. 1 by the control system ( 13 ) sending a suitable frequency control signal ( 18 ) to the frame-rate oscillator ( 15 ).
The appropriate control logic for this, slower output rate, conversion is shown in the flow chart of FIG. 4 . This is very similar to FIG. 3 , and analogous steps are given similar reference numerals, starting with 4 rather than 3. The steps which are different, depending on whether the required output rate is higher or lower than the input rate are as follows:
Step ( 42 )/( 32 )
When the output rate is lower than the input rate the buffer is tested to see if it is below a low threshold. When the output rate is higher than the input rate the buffer is tested to see if it is above a high threshold.
Step ( 44 )/( 34 )
When the output rate is lower than the input rate the interpolated rate is made slower than the output rate (so as to fill the buffer). When the output rate is higher than the input rate the interpolated rate is made faster than the output rate (so as to empty the buffer).
Step ( 48 )/( 38 )
When the output rate is lower than the input rate the buffer level is tested against a high threshold (to guard against overflow). When the output rate is higher than the input rate the buffer level is tested against a low threshold (to guard against under-flow).
Clearly the control system needs to make a decision as to which control logic to apply. In typical standards conversion applications the required output rate for a given conversion is always above, or always below, the input rate and so an initial operator instruction, or measurement of the input and output reference field rates, can be used to choose the appropriate mode of operation of the system. When the two frequencies are nearly equal it will usually be more appropriate not to interpolate, and to use a synchronisation technique using a small buffer, perhaps combined with the repetition or deletion of fields to avoid buffer under-flow or overflow.
There are some improvements that can be made to the control logic of FIGS. 3 and 4 to improve the transitions between the ‘synchronisation’ mode and the ‘interpolation’ mode. Rather than waiting for the interpolation phase to reach a low value, at steps ( 36 )/( 46 ), before changing to changing to the ‘synchronisation’ mode. The frequency of the interpolated fields (e.g. the frequency of the frame-rate oscillator ( 15 ) in FIG. 1 ) can be adjusted slightly as soon as the fall in confidence occurs so as to bring the phase difference to a low value within one or two fields, and thus enabling the change to synchronisation to be made sooner. Similarly, the interpolated field frequency can be adjusted to achieve a low interpolation phase value prior to the change from synchronisation to interpolation. By setting the buffer thresholds (as tested at steps ( 32 )/( 42 ) and ( 38 )/( 48 )) slightly within the acceptable buffer levels, additional time can be made available for achieving phase coincidence without buffer under-flow or overflow.
The above description has assumed a real-time process on streaming data. The invention may also be applied to non-real-time processing, including file-based processing. The invention relies on the ability to vary the field rate at will by interpolation when the confidence is high, in order to compensate for the incorrect instantaneous rate that occurs when interpolation is inhibited during periods of low confidence. The skilled person will appreciate that there are many ways in which a sequence of output images can be formed from temporally interpolated input images and un-interpolated input images, according to an interpolation confidence measure derived from the input images.
In the system of FIG. 1 the buffer ( 17 ), that enables temporal interpolation to be avoided when interpolation artefacts are likely, is placed after the temporal interpolation system ( 8 ). This need not be the case; it is equally feasible for the buffer to precede the interpolator, and an example of a suitable system is shown in FIG. 5 .
There are similarities between the system of FIG. 1 and the system of FIG. 5 , and analogous elements in the two figures have reference numerals that differ by 500. Referring to FIG. 5 , input image data ( 501 ) is converted to temporally interpolated image data ( 507 ) that is synchronous with output timing reference information ( 506 ). The input image data ( 501 ) is input to a FIFO buffer ( 517 ), and output from the buffer under the control of a frame-rate oscillator ( 515 ). When interpolation artefacts are not expected, the frame-rate oscillator ( 515 ) is locked to input timing reference timing information that is separated from the input image date ( 501 ) by an input timing information separator ( 502 ). The separated input timing information is routed by a switch ( 514 ) to a reference input of the frame-rate oscillator ( 515 ). The delay of the FIFO buffer ( 517 ) is thus constant because its input and output frame rates are locked together.
The output from the FIFO buffer ( 517 ) is temporally interpolated, by an interpolation system ( 508 ), to the frame rate of the output timing information ( 506 ). An output temporal phase accumulator ( 520 ) computes the required phase of each output field from the output timing reference information ( 506 ) and outputs an image request signal ( 510 ). This image request signal is sent to the interpolation system ( 508 ), in order to request the interpolation of a new output field. The required interpolation phase is determined by a sampler ( 516 ) that samples the phase of the frame rate oscillator ( 515 ) at the time of the image request signal ( 510 ).
When interpolation artefacts are expected, a control system ( 513 ) causes the switch ( 514 ) to route the output reference timing information ( 506 ) to the reference input of the frame-rate oscillator ( 515 ). This oscillator is now in phase with the output temporal phase accumulator ( 520 ); the interpolation phase is thus zero, and the interpolation system ( 508 ) passes its input fields to the temporally interpolated data output ( 507 ) without any temporal interpolation. Provided that the FIFO buffer ( 517 ) neither over- nor under-flows, it outputs (delayed) input fields at the required output rate under the control of the frame-rate oscillator ( 515 ).
The control system ( 513 ) manages the fill level of the FIFO buffer ( 517 ). When up-converting to a higher frame rate, there is a risk of buffer under-flow, but the buffer can be filled by reducing the frequency of the frame-rate oscillator ( 515 ) below the frame rate of the input image data ( 501 ). When down-converting to a lower frame rate there is a risk of buffer overflow, but the buffer can be emptied by increasing the frequency of the frame-rate oscillator ( 515 ) above the frame rate of the input image data ( 501 ).
Thus, as for the system of FIG. 1 , the buffer may be filled or emptied by modifying the rate of change of interpolation phase. When the FIFO buffer is placed after the temporal interpolator, the buffer is filled by increasing the frame-rate at the interpolator output above the required output frame-rate, and emptied by reducing the frame rate at the interpolator output below the required output frame-rate. When the FIFO buffer precedes the temporal interpolator, the buffer is filled by reducing the frame-rate at the interpolator input below the frame rate of the input image data, and emptied by increasing the frame rate at the interpolator input above the frame-rate of the input image data.
Therefore, the above-described interpolation systems each have three modes of operation:
Interpolation, where the buffer fill level is constant; Synchronisation, where the buffer level is changing; and, Buffer adjustment, where interpolation to or from a frame-rate other than the input frame-rate or the output frame-rate takes place and the buffer level changes in the opposite direction to the synchronisation mode.
A summary of the operation of each these modes, for up- and down-conversion, and for the two different positions of the FIFO buffer is as follows:
TABLE 1
Direction of
Position of
Mode of
Conversion
Buffer
Operation
Description
Up-
Buffer after
Conversion
Interpolator interpolates
Conversion
interpolator
new fields at output rate.
Output field-
Buffer fill level is
rate is higher
constant.
than input
Synchronisation
Unmodified input fields
field rate.
are input to buffer.
Buffer empties.
Buffer adjustment
Interpolator interpolates
new fields faster than
output rate.
Buffer fills.
Buffer
Conversion
Interpolator interpolates
precedes
new fields at output rate.
interpolator
Buffer fill level is
constant.
Synchronisation
Unmodified input fields
are taken from buffer at
output rate.
Buffer empties.
Buffer adjustment
Interpolator takes input
fields from buffer slower
than input rate.
Buffer fills.
Down-
Buffer after
Conversion
Interpolator decimates
Conversion
interpolator
input fields to create new
Output field
fields at output rate.
rate is lower
Buffer fill level is
than input
constant.
field-rate.
Synchronisation
Unmodified input fields
are input to buffer.
Buffer fills.
Buffer adjustment
Interpolator decimates
input fields to create new
fields slower than output
rate
Buffer empties.
Buffer
Conversion
Interpolator decimates
precedes
input fields to create new
interpolator
fields at output rate.
Buffer fill level is
constant.
Synchronisation
Unmodified input fields
are taken from the buffer
at output rate.
Buffer fills.
Buffer adjustment
Interpolator takes input
fields from buffer faster
than input rate.
Buffer empties.
The systems which have been described above avoid the need to drop or repeat fields when synchronising (as opposed to temporally interpolating), which is a significant disadvantage of prior-art systems that combine temporal interpolation and synchronisation modes. In the present invention the buffer is prepared in advance for future periods of synchronisation by adjusting its fill level. During this preparation, which is the ‘buffer adjustment’ described above, the frame-rate difference across the temporal interpolator is increased to a value greater than that between the input field-rate and the required output field-rate. As has been explained previously, this is achieved by changing the frame-rate at the interface between the buffer and the temporal interpolator. During periods of synchronisation the frame-rate at the input to the buffer is the input frame rate and the frame rate at the output from the buffer is the required output frame-rate; no frames are dropped or repeated and the fill level of the buffer changes (depending on the direction of conversion, up or down).
The use of the term FIFO (first-in-first-out) is not intended to imply a limitation to any particular implementation of the buffer function. The skilled person will appreciate that there are many ways in which a sequence of input frames or fields can be retimed without changing their order of presentation and without dropping or repeating fields or frames. For example, suitable addressing of a block of semiconductor memory could be used, or appropriate instructions for a processor.
The measure of temporal interpolation confidence that controls the choice between temporal interpolation and re-timing of input images without temporal interpolation need not necessarily be derived from the temporal interpolation process. It can be derived from;
analysis of the content of input images, or metadata associated with the input images; a motion estimation process; a comparison between an input image and a temporally interpolated image; or, a ‘picture building’ process that uses the motion vectors to construct temporally interpolated images.
Input images can be monitored to determine whether they contain spatial, temporal or spatio-temporal frequency components (including alias components) that are likely to cause interpolation artefacts. For example, the input images can be input to one or more suitable spatial, temporal or spatio-temporal filters that pass such frequencies, and the energy at the filter output used to derive an interpolation confidence measure that is low when significant energy levels are found. An approximate energy measure can be formed by rectification of a filter output and summation over the image area, alternatively a filter output value can be squared and a summation of squares made over the image area.
The use of the height of a peak or peaks in a correlation surface derived by phase correlation has already been described. Alternatively, known methods of cross-correlation between the values of pixels in adjacent input image can also be used to derive a correlation function, and the height of a peak or peaks in that function may be used to control a process according to the invention. When the peaks are high, the confidence in the temporal interpolation is high.
The use of displaced field or frame differences between an input image and a temporally interpolated image has already been described in relation to block matching—such comparisons can be made using images temporally interpolated by any known method of motion compensated temporal interpolation. Where the difference between a motion compensated input image displaced by one or more respective motion vectors and an appropriate undisplaced input image is low, the confidence in the temporal interpolation is high.
An interpolation confidence measure can be derived from a picture building process by evaluating the number of motion vectors that project input image pixels to a given temporally interpolated output pixel, as described in International Patent Application WO 2004/02598. If only one vector ‘points’ from an input pixel to a particular output pixel, then it is likely that that output pixel has been correctly interpolated, and the confidence in the interpolation will be high. If no vectors point to that output pixel, or if more than one vector points to it, then the likelihood of correct interpolation is low and the confidence in the interpolation will be low.
In some cases a measure of interpolation confidence can be obtained by comparison of the input images with temporally interpolated images, for example by using one or more of the methods for determining measures of interpolation artefacts described in UK patent application 1002865.2. Where the measure of interpolation artefacts is low, the confidence in the interpolation will be high.
It has already been mentioned that the confidence measure may be available prior to the actual interpolation of new pixels. When the buffer precedes the interpolator, the buffer delay can provide extra time in which to derive the confidence measure from analysis of the input image data.
In described embodiments of the invention, the temporal offset between the input and output images varies according to the fill level of the buffer. Generally, this variation is not objectionable; however, when the images need to be synchronised with some other material, such as accompanying audio or metadata, variations in temporal offset may be undesirable. The acceptability of variations in temporal offset may differ depending on the content of the video, for example ‘lipsync’ is important when speaking characters are portrayed, but is less important if the audio is background music. Therefore, in another aspect of the invention, a control input is provided to the control system ( 13 ) of FIG. 1 that indicates the acceptability of temporal offset. When this input indicates that temporal offset is undesirable, a positive weighting (or gain increase) is applied to the interpolation confidence measure so as to reduce the use of temporal interpolation and increase the use of re-timing.
Following the above described examples, a simplified block diagram representing an embodiment of the invention is shown in FIG. 6 . Image data ( 601 ) is input to the system. Timing information is extracted from the image data ( 601 ) by an input timing information separator ( 602 ) that outputs input image timing data that defines the start time of each of the fields in the image data ( 6011 ). Output reference timing information ( 606 ) is also input to the system; this information defines the required output field times and would typically be an output timing reference signal that identifies the required start time of each output field.
The image data ( 601 ) is input to a temporal interpolation system ( 608 ) with an associated buffer ( 617 ) which may be connected at the input or the output of the temporal interpolation system ( 608 ). The temporal interpolation system ( 608 ) outputs a ‘conversion confidence’ signal ( 612 ). This signal is a measure of the quality of the temporal interpolation, i.e. it is large when few interpolation artefacts are expected, and small when objectionable interpolation artefacts are expected. In a linear (i.e. non-motion-compensated) interpolator this measure could be related to the presence in the input fields of frequency components that are likely to be aliased by the temporal interpolation. The signal 612 is passed to a control unit ( 613 ) along with a buffer occupancy measure ( 625 ). It will be understood that the buffer occupancy measure may be inferred by the control unit and that a discrete signal path from the buffer to the control unit is not necessarily required and appears for clarity of understanding.
The control system ( 613 ) responds to the conversion confidence signal ( 612 ) and the buffer occupancy measure ( 625 ) to alter the operation of the system when necessary, so as to avoid so far as possible the output of fields showing interpolation artefacts and to avoid the necessity of dropping or repeating fields when retiming. Operation of the control unit ( 613 ) may be in accordance with Table 1 above. The control signals ( 611 ) may operate upon the interpolation system in a variety of ways evident to the skilled man. Switching of the input of a frame rate oscillator between input and output timings is just an example of how the controller may operate to select the synchronisation mode when the measure of temporal interpolation confidence is low and the measure of buffer occupancy indicates that images can be retimed without dropping or repeating of images and to select the interpolation mode when the measure of temporal interpolation confidence is high or when the measure of buffer occupancy indicates that images cannot be retimed without dropping or repeating of images. | A frame-rate conversion system having an interpolation mode and a synchronization mode. The synchronization mode is selected when temporal interpolation confidence is and images can be retimed without dropping or repeating of images. The interpolation mode is selected when the measure of temporal interpolation confidence is high or repeating of images. Images are exchanged between a temporal interpolator and a buffer at an exchange rate which is varied in the interpolation mode to optimise the buffer occupancy for retiming of images without dropping or repeating of images in s subsequent synchronization. | 7 |
BACKGROUND OF THE INVENTION
The instant invention relates to the field of surface mounted light fixtures having an internally mounted, externally actuated switch, and particularly to a unique structure for mounting such a switch within the housing of the fixture.
Surface-mounted light fixtures are particularly useful in applications when space is limited and a permanently mounted light is desired, as within the interior or on the exterior of, e.g., a recreational vehicle. Typically, a multiple position switch is mounted within the fixture and the light housing has an opening through which an actuator or the operating member of the switch extends for access by the user. To operate the switch, the user, in some such devices, may manipulate the operating member directly or, in other types, may manipulate the externally accessible actuator which correspondingly moves the operating member of the internally mounted switch. Since the most economical switches tend to have a very utilitarian and non-aesthetic appearance, and their operating members are similarly unattractive, it is very desirable to mount the entire switch and its operating member inside the light housing, where it will be out of sight, and to use a more attractive and aesthetically designed actuator located outside the housing to engage and move the hidden switch operator.
One known type of light fixture having a two-position switch contains an actuator that extends outside the fixture and operates a slide-type switch by pushing on either end of its outwardly facing surface. In such a system, the actuator for the slide-type switch operator is mounted on a rocker assembly which has a pin that is mounted within the housing of the fixture and upon which the actuator can rotate. The actuator has a "foot" on either end of its bottom surface, each of which is adapted to engage one side of the operating member when the user pushes that side of the actuator, thus sliding the operating member to turn the switch on or off. Although a rocker-type actuator has consumer appeal and true rocker-type switches imply a more costly and high-quality fixture, such a pseudo rocker structure is relatively complex and expensive to manufacture. In addition, such a structure having additional parts movable relative to one another is susceptible to malfunctioning.
In another type of light fixture containing a two-position switch, an actuator grips the top and side surfaces of the operating member of the switch so that when the user slides the actuator, the operating member correspondingly slides to open or close the switch contacts. The actuator member of these systems surrounds the entire operating member of the switch, thus making the construction of the actuator complex and expensive. In addition, known switches of this type are typically mounted to the back wall of the housing. In these light fixtures, the switch is secured with a rib structure that is connected to the back of the housing. However, the back of the housing in light fixtures of the type contemplated by the instant invention often have a removable back plate that is manufactured from thin sheet metal for reflecting light generated by a bulb. To keep the switch and its electrical contacts insulated and to avoid incorporating separate structure to attach the switch to the back wall, it is desirable to mount the switch within the polymeric housing, separate from the back wall.
Therefore, a light fixture is contemplated that has a housing which contains an integrated mounting structure capable of retaining the switch separate from the metal back plate of the fixture. In addition, it is desirable that such a light fixture have an actuator which will not only operate its switch repeatedly and reliably, but which will also be attractive in appearance and will properly cover the switch access opening in the housing to provide suitable weather protection. Further, it is highly desirable that such a fixture use a minimum number of parts, and that the parts be relatively inexpensive to manufacture and easy to assemble, so that the fixture is economical as well as reliable and the integrity and functionality of the switch are maintained.
SUMMARY OF THE PRESENT INVENTION
The light fixture switch system of the present invention provides a solution to the inadequacies and/or problems presented by the above known types of light fixtures, the switches contained therein and the mounting structures therefor. The housing of the instant light fixture is preferably constructed from a polymeric material and is molded to conform to various types of surfaces to which it will be anchored, e.g., the interior of a recreational vehicle. The housing has an opening in its front surface which is of sufficient size to admit portions of an actuator. The actuator has at least one leg which, when inserted into the opening of the housing, is adapted to flex and grip the side of the switch operating member after the switch has been mounted within the housing. The switch is mounted within the housing in inverted position so that the body of the switch is situated proximate the top wall of the housing and the operating member of the switch extends downwardly adjacent to and approximately at the center of the opening.
During assembly, the legs of the actuator are inserted into the opening of the housing. When the legs of the actuator contact the operating member, ramp surfaces on the free ends of the legs flex the legs outwardly. As the actuator is inserted further into the opening of the housing, the legs of the actuator flank both sides of the operating member while the head of the actuator comes into contact with the outside surface of the housing, thus preventing further inward movement of the actuator. In this position, the legs of the actuator are free to return to their normal position, i.e., flex back inward. Further, because the ramp surfaces of the legs define lip portions, the actuator "grips" the operating member of the switch to ensure that the actuator cannot inadvertently disengage from the housing.
In a preferred embodiment, the multiple position switch of the light fixture is supported in the housing of the light fixture by two mutually spaced internal walls that are integrated with the interior upper section of the housing and are spaced a sufficient distance to accommodate the switch. Each internal wall contains a slot which is adapted to receive one of the outwardly extending edges of the switch. The internal walls also contain elongated ribs of tapered cross section which protrude from opposing sides of the internal walls toward the interior of the space defined between the internal walls. These ribs engage the opposite sides of the switch as the switch is inserted between the two internal walls, flexing the walls outwardly at least a slight amount and thus stabilizing the switch within the housing and preventing it from shifting back and forth when it is actuated, notwithstanding instances where normal manufacturing tolerances might otherwise permit such shifting. Because the slots of the internal walls lie above the opening in the housing, the operating member of the switch is disposed adjacent to the opening in the housing when the switch is suspended upside down between the internal walls during assembly. Further, the interengagement between the operating member of the switch and the actuator prevents the switch from sliding out from between the internal walls of the housing and also retains the actuator in its proper position, thus serving a function of mutual retention.
The housing also contains a polymeric mounting plate integrally molded along its back peripheral edge. The mounting plate contains a series of mounting receptacles adapted to retain the back plate of the light fixture. Also, the back plate of the light fixture contains mounting structures for carrying a light bulb and, because it is typically constructed from thin sheet metal, it also disperses the light produced by the bulb. The mounting receptacles of the mounting plate of the housing contain apertures adapted to receive fastening structure for securing the housing to a supporting surface such as the interior wall of a recreational vehicle. The outside surface of each mounting receptacle also has a lip adapted to engage the peripheral edge of each aperture of the back plate so the back plate remains connected to the housing.
Importantly, the present invention overcomes the problems with previous light fixtures in that the switch is not mounted with separate supporting structures attached to either the back portion of the housing or the supporting surface. Also, the unique internal walls in accordance with the present invention are molded directly to the interior upper section of the housing, with the slots of the internal walls being above the opening in the housing. When the switch is mounted between the internal walls of the mounting structure, the operating member of the switch extends inwardly so that it readily engages the actuator. The switch is economically mounted near the internal top portion of the housing separate from the metal back plate, thus minimizing the required connecting structures and the chance of shorting the switch.
In addition, because the switch is separate from the back of the housing, the system can be readily disassembled for service of the components of the system, e.g., the light bulb or the switch, without disassembly of the system, including the actuator/switch assembly. Further, the present invention does not compromise the integrity of the mechanical operation between the actuator and the operating member of the switch. This result is efficiently and effectively accomplished because the actuator is a single rigid component, unlike previous inventions which use complex structures such as the rocker assembly described above. As a result, the light fixture of the instant invention is high quality, aesthetically pleasing, and inexpensive to manufacture.
These and other features, objects and advantages of the present invention will become apparent upon reading the following description thereof together with reference to the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a perspective view of a light fixture in accordance with the invention;
FIG. 2 is a front view of the light fixture of FIG. 1;
FIG. 3 is a rear view of the light fixture of FIG. 1, showing the multiple position switch mounted within the housing;
FIG. 4 is a rear view of the light fixture similar to FIG. 3, without the multiple position switch;
FIG. 5 is a cross-sectional side view taken along the plane V--V of FIG. 4;
FIG. 6 is a cross-sectional side view taken along the plane VI--VI of FIG. 3;
FIG. 7 is an enlarged fragmentary cross-sectional bottom view taken along the plane VII--VII of FIG. 3, showing the switch mounted within the housing; and
FIG. 8 is an enlarged fragmentary perspective inverted view showing the assembly of the light fixture.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to FIGS. 1 & 2, a light fixture 10 includes a polymeric housing 11, a molded polymeric lens 14 and an actuator 12 which passes through an opening 31 (shown in FIGS. 4 and 8) in the upper part of the housing. The housing and the lens are molded to conform to each other, with the lens being held within the housing by interengageable tabs and recesses (not shown) around the edge (the lens being at least slightly flexible for engagement and disengagement thereby). A mounting plate 22 (FIG. 3--described in more detail below) is molded along the lower back edge 19 of the housing. The lens preferably contains prismatic ridges (not shown) which disperse the light generated by a light bulb within the housing. The interior of the housing also has a series of molded stops 17 (shown in FIG. 3) against which the top edge of the lens rests to stabilize the lens 14 within the housing.
Referring next to FIG. 3, the rear of the housing 11 is shown with the back plate (described below) removed. Within the housing 11, the switch 16 of the light fixture 10 is mounted upside down, suspended from the underside of the top surface 13 of the housing by two mutually spaced internal walls 28, 29. In a preferred embodiment, the internal walls 28, 29 are molded to the inside top surface 33 of the housing 11 and, as best shown in FIG. 4, are situated on either side of an opening 31 in the top portion 15 of the housing.
Referring to FIG. 5, each internal wall 28, 29 has a pair of generally parallel but preferably slightly curving and convergent edges defining a slot 30 which has an open end 34 and a closed end 35. Each wall 28, 29 has an upper section 36 which is molded to the inside top surface 13 of housing 11, and a lower section 37 which is integrally attached to the upper section 36 at 35. The slots 30 are adapted to receive the switch 16 so that it is suspended upside down within the housing 11 (FIG. 3).
The light fixture 10 has a generally U-shaped mounting plate 22 which is integrally molded along the back edge 19 of the housing 11 (FIGS. 3-6 inclusive). The mounting plate 22 has a series of mounting receptacles 23 adapted to receive attaching means (e.g., screws) for holding the light fixture 10 to a supporting surface (not shown). Behind the mounting plate 22, fixture 10 preferably includes a back plate or rear closure plate (not shown) which, in the preferred embodiment, is constructed from a thin piece of sheet metal. The rear closure plate is preferably adapted to carry the light bulb of the fixture and, due to its metallic properties, reflects light emitted from the bulb. The rear closure plate contains a series of apertures adapted to receive the mounting receptacles 23 of the mounting plate 22, each of the mounting receptacles 23 containing a lip 27 designed to engage the edge of the apertures of the back plate to keep the back plate from separating from the housing. The back plate also contains an aperture through which the supply wires for the light source may be fed for connection to a power source, and the peripheral edges of this aperture preferably has an integral rolled edge, made during the stamping operation in which the back plate itself is formed, to avoid cutting or abrading such wires without the necessity of using a grommet or the like.
The switch 16 has a main body or base 25 (FIGS. 6 and 8) having a top surface 24 through which an operating member 20 extends. To operate the switch, the operating member 20 must be slid from side to side. The switch body 25 has a mounting plate 26 (FIGS. 3 and 7) disposed along top surface 24, with opposed wing-like ends which extend outwardly from the base or body 25. These wing-like ends of plate 26 are adapted to slide into the slots 30 of the internal walls 28, 29 of the mounting structure. The slots 30 are positioned in the internal walls 28, 29 so that when the switch is inserted, the operating member 20 of the switch extends downwardly below the lower section 37 of each internal wall and in alignment with the opening 31 in the housing, where the operating member will be in direct alignment with the actuator 12.
As shown in FIG. 3, the switch 16 also has a series of metal terminals 18 which extend outwardly from the bottom surface 21 of switch body 25 and to which the wiring 60 is connected. As will be understood, the wiring is also connected to the light bulb (not shown).
FIGS. 6, 6A, 7, and 8 show the engagement between the components of the system. The actuator 12 has a base 39 terminating in a pair of spaced legs 42 which enclose an opening 40. The legs 42 are spear-like, having ramped ends 44 defining hook-like lips 49 located at the end of base 39. The legs 42 are adapted to flex outwardly and are spaced apart a sufficient distance to receive the operating member 20 within opening 40. During assembly, switch 16 is placed in position as noted above and the actuator 12 is inserted through the opening 31 of housing 13. As the ramped ends 44 of the actuator legs 42 move along the opposite sides of the operating member 20, they flex the legs 42 outwardly but, at the point where the ramps 44 have moved past operator 20, legs 42 then spring back into place, with the edges of lips 49 hooked around the operator 20, thus locking the actuator 12 to the switch 16 to prevent inadvertent disengagement between the two and serve the mutual retention function noted above.
As best shown in FIGS. 3A, 4A, and 7, the internal walls 28, 29 each have an elongated rib 50 on their mutually facing sides which, in the preferred embodiment, are molded integrally thereto. The ribs 50 and walls 28, 29 are preferably sized and spaced so that the ribs 50 engage the sides of the switch body 25 (FIG. 3A) and flex the walls 28, 29 slightly outward as the switch is inserted therebetween, to insure a snug fit between the switch body 25 and the internal walls 28, 29. In the preferred embodiment, the ribs 50 are tapered in cross section and rounded to allow smooth sliding engagement between the switch body 24 and the ribs. When so mounted, the engagement between the switch body and the ribs stabilizes the switch laterally and holds it fly in position, which aids in assembly of the device and also helps insure consistent and proper switch operation.
As best shown in FIG. 8, the base 39 of actuator 12 basically comprises an elongated tongue or tab of rectangular cross-section, with legs 42 at one end and head 46 at the other. Immediately below head 46, base 39 is preferably "necked-down" or narrowed somewhat at 47, and directly below that, the base 39 has a ramp-like portion 38 integrally formed in each side. The narrowed portion 37 allows housing opening 31 to be commensurately reduced in width and facilitates coverage thereof at all times (in both positions of travel) by the actuator head 46. The ramps 38 enable actuator 12 to be self-retaining on housing 11, since they will slightly overlap the top and bottom edges of opening 31.
When the actuator is in its fully inserted position (see FIG. 6A), after having resiliently deflected these edges to the extent necessary during insertion of actuator base 39 through opening 31. This enables one to insert the actuator 12 into a self-retaining position before inserting switch 16 during assembly, such that the actuator 12 need not be manually held in place during insertion of switch 16, and also helps provide a smoothly operating, tightly connected and well-assembled product having no loose, rattling, or noisy parts.
To assemble the light fixture 10, the wing-like ends of the mounting plate 26 of the switch 16 are slid into the slots 30 of the internal walls 28, 29. The switch 16 is suspended upside down from the internal walls so that, when mounted, the operating member 20 of the switch extends downwardly adjacent to and in alignment with the opening 31 in the housing 11. With switch 16 so positioned, the actuator 12 is inserted through the opening 31 of the housing until the legs 42 of the base 37 engage the operating member 20 of the switch 16. As the actuator 12 is pushed further into the opening 31 in housing 11, the legs 42 of the actuator 12 flex outwardly. Thereafter, when the operating member 20 is fully enclosed by the opening 40 of the actuator, the legs 42 of the actuator return to their normal position. As described above, the actuator remains locked within the housing because the lips 49 of the ramped portions 44 of the actuator hook around the rear surfaces of the operating member 20 to capture the latter within opening 40. This prevents disengagement of the actuator 12 from the switch 16 and from the housing 13 during use, and also retains switch 16 in place, since the actuator 12 has a head 46 which is too large to fit through housing opening 31 in the event switch 16 is slid rearwardly in slots 30. Preferably, actuator head 46 has a concave surface 48 opposite the base 38, which facilitates manipulation by the user to slide operator 20 and turn the switch on and off.
In this preferred configuration, the switch 16, being mounted to the inside top surface 13 of the polymeric housing, is kept separate from the metal back plate to allow easy access to the bulb. In addition, separate structure to connect the switch is unnecessary because the switch is not connected to the back plate or the rear of the housing. In sum, the instant design efficiently utilizes the limited space contained within the housing 11 of the fixture, is relatively inexpensive to manufacture and greatly facilitates fast and easy assembly while also maintaining the integrity of the mechanical operation of the actuator/switch assembly.
It will become apparent to those skilled in the art that various modifications to the preferred embodiment of the invention as described herein can be made without departing from the spirit or scope of the invention as defined by the appended claims. | A light fixture with an actuator retained switch particularly adapted for surface mounting to a variety of supporting surfaces, e.g., the interior of a recreational vehicle, includes a housing, lens and mounting structure for suspending the switch within the housing. The mounting structure consists of a pair of mutually spaced internal walls which contain slots adapted to receive the edges of the switch. The switch is positioned between the two internal walls such that the operating member of the switch is in position to readily engage the switch actuator. Engagement of the switch operator and actuator serves to lock them together and retain both upon the housing. To operate the switch, the user manipulates the actuator, which is locked to the operating member of the switch, by sliding the actuator from side-to-side. | 7 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority from U.S. Provisional Application No. 61/526,352, filed Aug. 23, 2011, the entire disclosure of which is hereby incorporated by reference.
FIELD OF INVENTION
[0002] The present invention relates generally to a system and method of rapidly identifying a medical implant device and data associated with the device after implantation and apparatus employed to rapidly identify the medical implant.
BACKGROUND OF THE INVENTION
[0003] Medical implants are used in various surgical procedures to support or replace organs, bone, tissue or vessels. Information on the implant in use is sometimes entered in the patient's records in the hospital by medical personnel, but often there is little or no recorded data regarding the manufacturer, model or type of implant a patient has received from a prior surgery. This can create problems for other surgeons and during subsequent medical procedures in or around the area where the unrecorded device has been implanted, or create delays when a surgeon or other medical professional needs to identify, update, service, replace, or augment the implanted device.
[0004] With the frequency of recalls initiated by manufacturers and by the United States Food and Drug Association (“FDA”), there is greater emphasis being placed on the ability to identify and track implanted medical devices. A copy of a May 4, 2012 article published in the Denver Post, which is incorporated by reference herein in its entirety, demonstrates the importance of quickly and efficiently identifying a recalled implant: http://www.denverpost.com/nationworld/ci — 20544821/fda-lacks-system-trackingmedical-devices-that-malfunction?IADID=Search-www.denverpost.com-www.denverpost.com
[0005] One disadvantage of the prior art systems and methods is that the patient's record is archived in the hospital that carried out the implant, and therefore the patient has no information regarding the inserted implant. In an emergency or during a visit to a different doctor or different clinic, or during a follow-up surgery, the patient's record with the information on the implant must first be requested. Sometimes the patient has forgotten whether he is carrying an implant or may be unconscious after an accident, and cannot tell the medical personnel that he is carrying an implant. If it is a metal implant, this can be dangerous for the patient if, for example, he is being subjected to an examination using a magnetic resonance system. Because of these and other disadvantages, it is therefore usually necessary to examine the patient using an imaging process such as X-ray, CT or ultrasound to determine whether he is carrying an implant. However, this imaging procedure provides no detailed information, e.g. regarding the date of the implantation or the serial number of the implant.
[0006] In addition to biological and artificial permanent implants, auxiliary medical instruments and temporary implants that are removed after a certain time are often used. Such temporary implants are, for example, screws for fixing bones or attaching other implantable devices to the patient's boney anatomy. There are also a number of surgical instruments that are used when operating on the body of a patient, such as temporary heart pacemaker electrodes, catheters, guidewires, operating clamps, etc. The advantage of rapidly identifying the medical instrument is that it precludes the possibility of surgical instruments and temporary implants being left forgotten in the body of the patient during an operation or that have failed to have been removed in a timely and safe manner.
[0007] Surgeons now have the ability to readily convert, for example, x-ray data, magnetic resonance imaging (MRI) data or computed tomography (CT) data into usable image data for determining the general characteristics of a particular implant device. However, present prior art systems for capturing such image data do not facilitate the accurate identification of the device properties, such as manufacturer, model, date, expiration, size, etc. The image data obtained may therefore also include indicia, such as markers, which may be arranged in a unique manner for identifying the device.
[0008] Therefore, a present need is felt to provide a system and method of rapidly determining the manufacturer and model and other information relating to an implanted medical device. The benefits, embodiments, and/or characterizations described herein are not necessarily complete or exhaustive, and in particular, as to the patentable subject matter disclosed herein. Other benefits, embodiments, and/or characterizations of the present disclosure are possible utilizing, alone or in combination, as set forth above and/or described in the accompanying figures and/or in the description herein below.
SUMMARY OF THE INVENTION
[0009] The present invention is directed to a system and method for rapidly and accurately identifying an implantable medical device, said identification including, for example, the manufacturer and model or type of the implantable device, the date the implant was implanted, any recall or other future data associated with the implant since the date of implanting the device, and further assisting the surgeon and other medical professionals in identifying the instruments used to adjust and/or remove the medical device. One or more characteristics of the implant may be identified using the system and method of the present disclosure from an image of the implant or indicia readable on the implant and retrieved by various means of imaging an implantable device after it has been implanted.
[0010] The system and method described in the present disclosure utilizes, for example, x-ray data, magnetic resonance imaging (MRI) data or computed tomography (CT) data, which may be used to provide a surgeon or medical professional with accurate means of identifying implant device properties, such as manufacturer, model, date, expiration, size, etc. In one particular embodiment, the image data obtained may include indicia, such as markers, which may be arranged in a unique manner for identifying the device. In yet other embodiments, the image of the implant device may have other unique characteristics, such as geometric characteristics, that are associated with a particular implant.
[0011] Medical implants in this application include implants that are used to improve the health of the patient and also those used for aesthetic reasons. They may include spinal implants, cardiovascular implants, orthopedic implants, neurological implants or other medical apparatus inserted into or surgically attached to a patient, including screws, plates, rods, prosthetics, pacemakers, etc.
[0012] By way of example but not limitation, in total joint replacement, if the medical implant device is monitored for any change in alignment, wear or loosening during the lifetime of the implant, the system and method described herein may be used to identify the specific implant and the associated specifications for that implant, which over the course of several years and often required follow-up surgical procedures, may not be immediately discoverable from the patient's medical files and or known to the surgeon.
[0013] In further embodiments of the present disclosure, the medical implant device may be recognized by the placement and/or pattern of one or more radiolucent or other readable markers embedded within or adjacent to the surface of the implant device. In yet another embodiment, a plurality of markers may be arranged to form a readable bar code or other pattern-coded indicia. In one embodiment the markers may be formed from thin strips of material that have at least one surface comprising an adhesive element, which may be selectively adhered to the surface of the implant device by a manufacturer, distributor or user of the medical implant device.
[0014] An independent or networked computational piece of machinery, hereinafter referred to as an image-displaying apparatus, may be used for recognizing identifying marker(s) and comparing the identifying marker(s) to a database of known medical implant devices to determine the precise implant associated with the identifying marker(s).
[0015] According to one aspect of the present disclosure, a system for identifying a medical implant is disclosed, comprising:
[0016] an implanted device, the implanted device comprising one or more indicia;
[0017] a database containing a plurality of records for various implantable devices, each of the various implantable device associated with at least one record comprising associated indicia and other data relating to the implantable device;
[0018] an image-displaying apparatus comprising means for displaying a user interface, the image-displaying apparatus and user interface comprising means for accessing the database; wherein the one or more indicia are discernible by at least one of the following: an x-ray, fluoroscopy, computed tomography, electromagnetic radiation and magnetic resonance imaging;
[0019] wherein the one or more indicia are arranged in a manner that is unique to a particular implanted device; and
[0020] wherein the image-displaying apparatus and the user interface are configured to access the records in the database and compare the one or more discernible indicia to the plurality of records for identifying the other data relating to the implantable device.
[0021] The system may also employ means for ensuring confidentiality of the patient related information. As those skilled in the art will appreciate, any computers or computational machinery discussed herein may include an operating system (e.g., Windows 7, Windows Vista, NT, 95/98/2000, OS2; UNIX; Linux; Solaris; MacOS, Snow Leopard; etc.) as well as various conventional support software and drivers typically associated with computers. The computers or computational machinery may be in a mobile or personal or business environment with access to a network. In an exemplary embodiment, access is through the Internet through a commercially-available web-browser software package. These and other benefits of the present disclosure are described in greater detail in the Detailed Description.
[0022] The Summary of the Invention is neither intended nor should it be construed as being representative of the full extent and scope of the present disclosure. The present disclosure is set forth in various levels of detail in the Summary of the Invention as well as in the attached drawings and the Detailed Description of the Invention and no limitation as to the scope of the present disclosure is intended by either the inclusion or non-inclusion of elements, components, etc. in this Summary of the Invention. Additional aspects of the present disclosure will become more readily apparent from the Detailed Description, particularly when taken together with the drawings.
[0023] The above-described benefits, embodiments, and/or characterizations are not necessarily complete or exhaustive, and in particular, as to the patentable subject matter disclosed herein. Other benefits, embodiments, and/or characterizations of the present disclosure are possible utilizing, alone or in combination, as set forth above and/or described in the accompanying figures and/or in the description herein below. However, the claims set forth herein below define the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the disclosure and together with the general description of the disclosure given above and the detailed description of the drawings given below, serve to explain the principles of the disclosures.
[0025] It should be understood that the drawings are not necessarily to scale. In certain instances, details that are not necessary for an understanding of the disclosure or that render other details difficult to perceive may have been omitted. It should be understood, of course, that the disclosure is not necessarily limited to the particular embodiments illustrated herein.
[0026] In the drawings:
[0027] FIG. 1 is a schematic view of a system for identifying a medical implant according to an embodiment of the present disclosure;
[0028] FIG. 2 is another schematic view of the system according to an embodiment of the present disclosure;
[0029] FIG. 3 is another schematic view of the system according to an embodiment of the present disclosure;
[0030] FIG. 4 is a perspective view of a medical implant device and associated indicia according to a certain embodiment of the present disclosure; and
[0031] FIG. 4 is a flow chart diagram showing the steps of a method for identifying a medical implant according to an embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE INVENTION
[0032] The invention provides a mobile application for identifying a medical implant device in a human, or in certain embodiment an animal. Various aspects of the invention described herein may be applied to any of the particular applications set forth below or for any other types of user interfaces and image-displaying apparatus, or to various data management applications. The invention may be applied as a standalone system or method, or as part of an integrated package, such as a medical and/or data management application. It shall be understood that different aspects of the invention can be appreciated individually, collectively, or in combination with each other.
[0033] The system and method described in the present disclosure utilizes data, for example, x-ray data, magnetic resonance imaging (MRI) data or computed tomography (CT) data, which may provide a surgeon or medical professional with accurate means of identifying implant device properties, such as manufacturer, model, type, material, version, revision, date of manufacture, date of surgery, expiration, size, etc. In one particular embodiment, the data obtained may include indicia, such as markers, which may be arranged in a unique manner for identifying the device. In yet other embodiments, the image of the implant device may have other unique characteristics, such as geometric characteristics, that are associated with a particular implant.
[0034] In one particular embodiment of the present disclosure, the medical implant device may be recognized by the placement and/or pattern of one or more radiolucent or other readable markers embedded within or adjacent to the surface of the implant device. In yet another embodiment, a plurality of markers may be arranged to form a readable bar code or other pattern-coded indicia. An independent or networked computational piece of machinery or image-displaying apparatus may be used for recognizing identifying marker(s) and comparing the identifying marker(s) to a database of known medical implant devices to determine the precise implant associated with the identifying marker(s).
[0035] In one particular embodiment, the indicia are formed by the use of markers, which due to their location, orientation, sizing, spacing, etc. form a unique pattern. By way of example but not limitation, the markers may be arranged such that they form an array or pattern of dots or similar shapes when viewed by known imaging equipment, such as a CT or MRI scanner. The array or pattern may be unique to the particular implant, with certain dots or shaped markers corresponding to the manufacturer, while others refer to the date the implant was manufactured or the date the device was implanted. In yet another embodiment, the markers may be viewed in one particular orientation of the implant as a series of bars. In this embodiment, the spacing, height and thickness of the markers which form the bars may be unique to a particular implant, and provide a surgeon or other medical professional with a unique identification means for locating data files or records associated with the particular implant device. Further illustration of these concepts is provided in detail below.
[0036] Referring now to the drawing figures, the appended FIG. 1 shows a system 2 for identification of medical implants. This embodiment of the present disclosure comprises a image-displaying device 8 and a scanning unit 4 for processing data related to at least one device implanted into the body of a patient 6 . The scanning unit 4 and image-displaying device 8 are, according to a preferred embodiment, further associated with a central data repository 10 . The scanning unit, which is used to convert one of several known image types into a format that can be viewed via the image-displaying device, may be of a number of different forms, so long as it is capable of obtaining image-related information relating to the device implanted into the patient.
[0037] The system and method shown in FIG. 1 is designed to be used with, in particular, an imaging examination device, e.g. an x-ray system, which may in certain embodiments be later digitized by employing the scanning unit 4 or other equipment available for such conversion. When the scanning unit 4 receives information on the implant from the x-ray system, for example, the data can be exported to the image-displaying device 8 , which is connected in a preferred embodiment by wireless transmission to the central data repository 10 .
[0038] In this embodiment, the central data repository 10 contains the data files or records associated with various manufacturers, models and types of implant devices. This system then compares the data exported to the mobile electronic device to the data files associated with various implant devices contained in the central data repository 10 , e.g., the device characteristics, for accurately identifying the implant device.
[0039] In general, the scanning unit 4 provides optical pattern recognition of any two-dimensional or three-dimensional object, such as an x-ray image or other image. The scanning unit 4 may incorporate any algorithms, modalities, processes or formats known in the art without departing from the scope of the present disclosure. In one embodiment, the scanning unit 4 is used to digitally scan a two-dimensional image of a patient's anatomy and associated medical devices to be identified. In another embodiment, the scanning unit 4 may scan and process the data from the scan. For example, the comparison algorithm and methods for comparing two images described in U.S. Pat. No. 8,175,412, which is incorporated by reference herein in its entirety, may be used to compare the image obtained from the implanted device to a plurality of records stored in a central data repository to match the device to the data file associated with a device having the identical unique identification characteristics. Thus, according to this embodiment, the image-displaying device is not necessary.
[0040] Referring back to FIG. 1 , the scanning unit converts the image of the implant device to a format that is received and is readable by the image-displaying device 8 , which permits a user to call up the image of the implanted device and the associated data from the central data repository 10 in a convenient location. The image-displaying device 8 then communicates with and accesses data stored in the central data repository 10 , which then communicates data associated with the medical device, such as the manufacture, model, type, revision, etc., back to the image-displaying device 8 .
[0041] Referring now to the embodiment shown in FIG. 2 , various types of mobile electronic devices may be used as the image-displaying device, which may also be connected to an information system located on a server 22 of the hospital. An electronic record of the patient can thus be automatically called up or created in which data, e.g. regarding the examination, treatment or condition of the patient are then stored. In this manner, the information system may be used to store new data related to the implant. This information may be transferred via https (Hyper Tech Transfer Protocol Secure) and/or SSL (Secure Socket Layer) protocols to ensure the transaction(s) and associated patient information exchanged between the user and the system described herein remain secure.
[0042] The central data repository associated with the system described herein may be utilized for storing data related to the transactions processed by a remote machine hosted application programming interface (API). The central data repository may have one or more permanent or removable memory storage devices, which may be periodically updated as new medical devices are introduced. Although the central data repository may be comprised of a single, integrated structure, it is expressly understood that several discrete storage mediums, which may or may not reside in the same location, may be used without departing from the spirit of the present disclosure.
[0043] One aspect of the present disclosure contemplates the use of various software elements to complete the transactions described above, provide the user with corresponding graphic user interface displays, etc. The software elements of the present disclosure may be implemented with any programming or scripting language such as C, C++, Java, COBOL, assembler, PERL, Visual Basic, SQL Stored Procedures, AJAX, extensible markup language (XML), with the various algorithms being implemented with any combination of data structures, objects, processes, routines or other programming elements. Further, it should be noted that the present disclosure of the claimed invention may employ any number of conventional techniques for data transmission, signaling, data processing, network control, and the like. Still further, embodiments of the claimed invention may detect or prevent breaches in security with a client-side scripting language, such as JavaScript, VBScript or the like.
[0044] A user interface provided in accordance with the invention described in varying embodiments herein may be displayed across a network such as the Internet or a wireless communication network. For example, an implementation may include a client device comprising a video display with at least one display page comprising data. The data may include medical data, such as patient data (e.g., medical history, patient history, prior medical treatment, physician entered data, etc.), surgical history and treatment logs (e.g., various visit or treatment information, patient assessments, patient notes, access history/usage), and any associated interfacing data (e.g., machine data or hospital-related data). In some embodiments, the data provided may be urgent data that may require immediate or quick actions in response.
[0045] Communication among the parties in accordance with the present disclosure may be accomplished through any suitable communication channels, such as, for example, a telephone network, an extranet, an intranet, Internet, point of interaction device (point of sale device, personal digital assistant, cellular phone, kiosk, etc.), online network communications, wireless communications, local area network (LAN), wide area network (WAN), networked or linked devices and/or the like. Moreover, although the network communications may be implemented with TCP/IP communications protocols, such communications may also be implemented using IPX, Appletalk, IP-6, NetBIOS, OSI or any number of existing or future protocols. Specific information related to the protocols, standards, and application software utilized in connection with the Internet is generally known to those skilled in the art and, as such, need not be detailed herein. See, for example, DILIP NAIK, INTERNET STANDARDS AND PROTOCOLS (1998); JAVA 2 COMPLETE, various authors, (Sybex 1999); DEBORAH RAY AND ERIC RAY, MASTERING HTML 4.0 (1997); and LOSHIN, TCP/IP CLEARLY EXPLAINED (1997), the contents of which are hereby incorporated by reference.
[0046] Another embodiment of the present disclosure is shown in FIG. 2 , wherein a mobile device 60 is comprised of a display 62 , one or more controls 64 , and further comprises an internal memory 66 for storing data, such as image data and device characteristic data, for example. The mobile device 60 may communicate 26 with a server 22 or similar network device located at a hospital or other medical facility, which may house an information system 20 and, which may also have an internal memory 30 (and permits synchronization and communication with the mobile device 60 ). The server 22 communicates 14 with a central data repository 10 ′, where data relating to the dimensions, specifications, characteristics, appearances or other information or indicia related to specific medical devices may be stored and retrieved by the user of the mobile device 60 .
[0047] The central data repository 10 according to this particular embodiment may also have one or more permanent or removable memory storage devices 12 , which may be periodically updated as new medical devices are introduced. Although in FIG. 2 the central data repository 10 is shown as a single, integrated structure, it is expressly understood that several discrete storage mediums, which may or may not reside in the same location may be used without departing from the spirit of the present disclosure.
[0048] For example, referring now to FIG. 3 , a schematic diagram is shown which permits a mobile device running a mobile application 70 to connect to a network that comprises a plurality of data storage mediums A, B, C, Z. The mobile application 70 may further communicate over this network with an algorithmic processor or data management software 72 , which may reside, for example, on the server 22 (as shown in FIG. 2 ). According to yet another embodiment, the data management software 72 may reside on a remote server, and be accessed via login and password information supplied by the user of the mobile device 60 via the mobile application 70 . In this embodiment, data related to a certain manufacturer's medical devices may reside in the storage medium A, while another medical device manufacture's data may reside on storage medium B, and so on. In this manner, the data management software 72 and/or the mobile application 70 may be configured to allow a user to access data on any one of these storage mediums shown in FIG. 3 .
[0049] In one particular embodiment, indicia embedded within or adjacent to the surface of the device to be identified are arranged in a unique manner. It is expressly understood that the use of the term indicia is not intended to be limiting to writings or graphically represented indicia. To the contrary, the present disclosure involves in one embodiment the use of RFID elements or other embedded elements within the implant device, which may serve as indicia capable of translation to a user for identifying the device. In this particular embodiment, one or more unique RFID tags, each comprising a unique frequency or code (or in alternate embodiments, having the same frequency or codes), may be embedded in the medical implant device and may be detected by a reading device, such as the type described in U.S. Pat. No. 8,114,063, the entirety of which is incorporated by reference herein.
[0050] Referring now to FIG. 4 , one particular embodiment of the present disclosure depicting an implantable device comprising markers for determining the unique identification characteristics of the device is shown. The implant device shown in FIG. 4 comprises a first surface 16 and a second surface 17 which are spaced apart from one another, thereby creating a void between the first surface 16 and second surface 17 , wherein said void is accessible via apertures 11 a , 11 b shown in a top surface 11 of the implant. The implant may further comprise one or more attachment points 13 for attaching an instrument for inserting the implant device.
[0051] According to various embodiments described herein, the implant device may further comprise a series of markers, wherein the markers may be arranged in particular arrays (shown in FIGS. 4 as 15 b , 15 c , 15 d and 15 e ). Markers may also be provided independently, such as in 15 a and 15 b shown in FIG. 4 . According to one embodiment, a particular array of markers 15 b may be comprised of different sized markers, different shaped markers and differently oriented markers to create a recognizable pattern or code by the particular size, shape, orientation, placement, etc. of the markers. By way of example but not limitation, the array of markers 15 b may correspond to a particular manufacturer of the implant device. In this manner, a separate array of markers 15 c may correspond to another characteristic of the implant device, such as the date of manufacture. Similarly, a separate array of markers 15 d may correspond to a model or implant type, while yet another separate array of markers 15 e may correspond to a date of surgery wherein the implant device shown in FIG. 4 was implanted.
[0052] In the embodiment shown in FIG. 4 , the markers are shown as corresponding with dots, which may be embedded in the surface of the implant (e.g., implanted in the first surface 16 for arrays of markers 15 b and 15 d , and embedded into the second surface 17 for arrays of markers 15 c and 15 e ). Alternatively, the markers may be placed on the surface of the implant, either by the manufacturer, distributor, surgeon or other medical professional.
[0053] In yet another embodiment, the markers may be comprised of rectangular or cylindrical prism shaped markers, which may be arranged in a horizontal, vertical or other orientation for representing characteristics of the implant device. As with the dot shaped marker shown in FIG. 4 , the rectangular or cylindrical prism shaped markers may be arranged according to height, thickness, location and/or orientation, etc. to convey certain data relating to the medical device. The rectangular or cylindrical shaped markers may be embedded into the surfaces of the implant device or may be placed on the exterior or interior surfaces of the implant device as described above.
[0054] According to one embodiment, the implant device may further comprise one or more RFID elements ( 15 g , 15 h ), which are ideally embedded into one or more of the surfaces of the implant device for further identifying the implant device or characteristics associated with the implant device. These RFID elements may be RFID tags, coils, transponders or other known RFID elements capable of being scanned and conveying data to a scanning unit external to the human or animal subject in which the implant device has been implanted into.
[0055] Referring now to FIG. 5 , a preferred embodiment for performing a method of identifying a medical implant device is shown. In the first step 130 , the implant device is imaged using one of a plurality of imaging techniques. Next, the image is decoded 140 , either by removing unnecessary and/or unwanted data associated with the image or extracting one or more indicia associated with the implant device. The next step 150 involves providing the decoded image file or associated indicia to the central data repository, where the API or other equivalent software performs the algorithms necessary to compare the decoded image or associated indicia to a plurality of unique records of all known medical implant devices. Next, the unique medical implant device corresponding to the decoded image file or associated indicia is identified 160 and at least one data file associated with the identified implant device is provided to the user 170 , preferably via a hand held device containing a user interface. In the next step 180 , the user may visibly verify that the data file received corresponds to the implant device. The final step 190 is updating the patient records associated with the medical implant device.
[0056] Many of the components of the disclosure made herein may be described as being “in communication” or “in operable communication” with other components. Being “in communication” or “in operable communication” refers to any manner and/or way in which functional units or modules, such as, but not limited to, computers, laptop computers, tablets, PDAs, mobile networking devices, modules, network servers, routers, gateways, and other types of hardware and/or software, may be in communication with each other. Some non-limiting examples include: (i) activating or invoking another such functional unit or module, and (ii) sending, and/or receiving data or metadata via: a network, a wireless network, software, instructions, circuitry, phone lines, Internet lines, satellite signals, electric signals, optical signals, electrical and magnetic fields and/or pulses, and/or so forth.
[0057] Video displays may include devices upon which information may be displayed in a manner perceptible to a user, such as, for example, a computer monitor, cathode ray tube, liquid crystal display, light emitting diode display, touchpad or touch screen display, and/or other means known in the art for emitting a visually perceptible output. Video displays may be electronically connected to a client device according to hardware and software known in the art. Displays may be incorporated in one or more portable desktop accessories (“PDAs”) or other mobile devices, including but not limited to an iPhone.
[0058] At a client device, the display page may be interpreted by software residing on a memory of the client device, causing a file to be displayed on a video display in a manner perceivable by a user. The display pages described herein may be created using a software language known in the art such as, for example, the hypertext markup language (“HTML”), the dynamic hypertext markup language (“DHTML”), the extensible hypertext markup language (“XHTML”), the extensible markup language (“XML”), or another software language that may be used to create a computer file displayable on a video display in a manner perceivable by a user. Any computer readable media with logic, code, data, instructions, may be used to implement any software or steps or methodology. Where a network comprises the Internet, a display page may comprise a webpage of a type known in the art.
[0059] A display page according to the invention may include embedded functions comprising software programs stored on a memory, such as, for example, Cocoa, VBScript routines, JScript routines, JavaScript routines, Java applets, ActiveX components, ASP.NET, AJAX, Flash applets, Silverlight applets, or AIR routines.
[0060] A display page may comprise well known features of graphical user interface technology, such as, for example, frames, windows, tabs, scroll bars, buttons, icons, menus, fields, and hyperlinks, and well known features such as a touch screen interface. Pointing to and touching on a graphical user interface button, icon, menu option, or hyperlink also is known as “selecting” the button, icon, option, or hyperlink. Any other interface for interacting with a graphical user interface may be utilized. A display page according to the invention also may incorporate multimedia features.
[0061] A user interface may be displayed on a video display and/or display page. A server and/or client device may have access to data management and/or associated software. A user interface may be used to display or provide access to medical data. For example, a user interface may be provided for a web page or for an application. An application may be accessed remotely or locally. A user interface may be provided for a mobile application (e.g., iPhone application), gadget, widget, tool, plug-in, or any other type of object, application, or software.
[0062] Any of the client or server devices described herein may have tangible computer readable media with logic, code, or instructions for performing any actions described herein or running any algorithm. The devices with such computer readable media may be specially programmed to perform the actions dictated by the computer readable media. In some embodiments, the devices may be specially programmed to perform one or more tasks relating to data management. In some embodiments, the devices may communicate with or receive data collected from one or more measurement or sensing device, which may collect physiological data from a subject or from a sample collected from a subject.
[0063] In another embodiment, new or existing image management software could be incorporated with the system described above to analyze the two-dimensional image received from the scanning unit 4 , and directly report the data associated with the medical device. For example, image management software known as DICOM could receive this type of data and be used in conjunction with the present disclosure.
[0064] In one alternative embodiment, the present disclosure may be used in conjunction with a plurality of identification markers. U.S. Pat. No. 7,901,945 is hereby incorporated by reference in its entirety for the purpose of supplementing this disclosure with respect to incorporating a method of image recognition by use of identification markers, biosensors, micro-fluidic arrays and optical character recognition.
[0065] According to yet another alternative embodiment, the scanning device 10 may be eliminated by incorporating the functionality of the scanning unit 4 with the mobile device 8 . In this embodiment, the mobile device further comprises means for scanning the two-dimensional object and processing the data associated with the two-dimensional object without the need for a separate, independent scanning unit.
[0066] U.S. Pat. No. 7,855,812 is incorporated by reference herein in its entirety for the purpose of supplementing this disclosure with respect to scanning of high resolution two-dimensional images and converting those images for use in a mobile device such as a cellular phone.
[0067] The implants described herein may be made of a variety of different materials. These materials may include, by way of example but not limitation, stainless steel, titanium alloy, aluminum alloy, chromium alloy, and other metals or metal alloys. These materials may also include, for example, PEEK, carbon fiber, ABS plastic, polyurethane, resins, particularly fiber-encased resinous materials rubber, latex, synthetic rubber, synthetic materials, polymers, and natural materials. The markers described herein may similarly be made from a variety of materials, including but not limited to radiolucent materials.
[0068] While various embodiment of the present disclosure have been described in detail, it is apparent that modifications and alterations of those embodiments will occur to those skilled in the art. However, it is to be expressly understood that such modifications and alterations are within the scope and spirit of the present disclosure, as set forth in the following claims. For further illustration, the information and materials in appended Exhibit A hereto are expressly made a part of this disclosure and incorporated by reference herein in their entirety.
[0069] The foregoing discussion of the disclosure has been presented for purposes of illustration and description. The foregoing is not intended to limit the disclosure to the form or forms disclosed herein. In the foregoing Detailed Description for example, various features of the disclosure are grouped together in one or more embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed disclosure requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate preferred embodiment of the disclosure.
[0070] Moreover, though the present disclosure has included description of one or more embodiments and certain variations and modifications, other variations and modifications are within the scope of the disclosure, e.g., as may be within the skill and knowledge of those in the art, after understanding the present disclosure. It is intended to obtain rights which include alternative embodiments to the extent permitted, including alternate, interchangeable and/or equivalent structures, functions, ranges or steps to those claimed, whether or not such alternate, interchangeable and/or equivalent structures, functions, ranges or steps are disclosed herein, and without intending to publicly dedicate any patentable subject matter. | A system and method for rapidly and accurately identifying an implantable medical device is disclosed, said identification including, for example, the manufacturer and model or type of the implantable device, and further assisting the surgeon and other medical professionals in identifying the instruments used to adjust and/or remove the medical device. | 0 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to well cleaning or opening methods and apparatus, and is more particularly concerned with a combination surging and jetting method and apparatus.
2. Discussion of the Prior Art
It is common for wells of various types to become clogged, so cleaning is necessary for the well to continue to function. Also, when wells are first drilled, the surrounding area may be naturally clogged enough to retard or prevent fluid flow. Sometimes the clog in the well is due to corrosion, accumulation of inorganic materials or the like, and sometimes the clog in the well is due to growth of bacterial colonies. The latter is discussed in more detail in U.S. Pat. No. 4,765,410, and that disclosure is incorporated herein by this reference.
The method disclosed in the above mentioned patent utilizes a jet for some cleaning of the well screen and of the interior of the well casing, then relies on a circulation of heated solution, and perhaps some pressure, for thorough cleaning of the well screen and the gravel pack.
Another common technique for use in cleaning wells is surging, in which a surge block substantially fills the well casing, and is reciprocated within the well casing to cause a reciprocating fluid flow. This fluid flow assists in breaking loose clogging material, and can force chemicals used out into the aquifer.
When both jetting and surging are to be used on the same well, one tool has been inserted and used, then that tool removed from the well and the other tool inserted into the well for use. Repetitions of the treatments required repetitions of the removal and re-insertion which requires much time and labor.
SUMMARY OF THE INVENTION
The present invention provides a combination surge block and jetting tool, the jetting tool being carried by the surge block. The surge block defines fluid passages therethrough for delivering fluid to the jetting tool. The jetting tool is preferably substantially centered with respect to the surge block so the surge block holds the jetting tool generally centered with respect to the well casing and well screen.
Conduit means connect to the top side of the surge block and communicate with the passages therein. The conduit may also be the holding and control means for the surge block, or an additional cable or the like may be used.
Thus, in accordance with the method of the present invention, one can quickly alternate between jetting and surging, and can use both jetting and surging simultaneously so the surging currents include the chemicals supplied by jetting.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features and advantages of the present invention will become apparent from consideration of the following specification when taken in conjunction with the accompanying drawings in which:
FIG. 1 is an elevational view showing a tool made in accordance with the present invention, the tool being within a well which is shown in cross-section;
FIG. 2 is an enlarged diametrical cross-sectional view of the tool shown in FIG. 1;
FIG. 3 is a fragmentary view taken along the line 3--3 in FIG. 2; and,
FIG. 4 is a view similar to FIG. 2 but showing a modified form of the tool.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Referring now more particularly to the drawings, and to those embodiments of the invention here presented by way of illustration, FIG. 1 shows a well casing 10 having a well screen 11 at the lower end thereof. As is conventional, the well screen 11 has a gravel pack therearound as indicated at 12. When a well becomes clogged, the well screen 11 may be clogged and/or the gravel pack 12 may be so clogged as to be substantially non-porous.
The basic techniques in cleaning a well include the introduction of chemicals to break up the clogging material in order to promote free flow, spraying the interior of the well casing and screen with chemicals under high pressure, and surging to cause reciprocating currents for mechanically loosening clogging material.
The apparatus of the present invention includes a surge block generally designated at 14, the surge block 14 being shown as disposed within the well casing 10. The surge block includes a central body 15 having upper and lower disks 16 and 18 fixed thereto. The disks 16 and 18 substantially fill the well casing 10, so the action of moving the surge block 14 within the well casing is similar to the action of moving a piston within a cylinder. The disks 16 and 18 are preferably somewhat flexible, and this will be discussed in more detail hereinafter.
The top end of the surge block has a conduit 19 fixed thereto. The conduit may simply deliver fluid, or may also act as the means for moving the surge block. Also, when desired, an eye 20 may be fixed to the surge block 14, the eye 20 receiving a cable or the like for controlling movement of the surge block 14.
The lower end of the surge block 14 carries a jetting tool generally designated at 21. The purpose of the jetting tool 21 is to direct a cleaning fluid against the interior of the well casing, and the well screen, to loosen or remove clogging material. It is important to notice that the nozzle of the jetting tool 21 is significantly smaller than the diameter of the well casing 10. When the jetting tool 21 is in the vicinity of the well screen 11, jets of liquid ought not to be discharged directly through a hole in the screen 11. The high pressure fluid passing directly into the gravel pack 12 will disturb the gravel pack, and will place a substantial amount of chemicals into the aquifer.
Thus, in the device of the present invention, the jetting tool has a small diameter relative to the diameter of the well casing 10. The fluid is introduced at high pressure, and the fluid becomes dispersed before reaching the well screen.
Looking at FIG. 2 of the drawings, it can be seen that the central body 15 of the surge block 14 is generally cylindrical, and defines a fluid passage 22 axially therethrough. The upper end of the passage 22 is threaded at 24, and the lower end of the passage 22 is threaded at 25. The threads 24 and 25 are here shown as tapered pipe threads, but those skilled in the art will understand that a conventional machine thread may be used if desired. However, if standard pipe is used as the conduit 19 and the connection 26 for the jetting tool 21, the pipe threads may be preferred.
The disks 16 and 18 are preferably flexible enough to allow the disks to bend under reasonably large forces. The purpose is not to damage the well casing or screen, and to provide relief in the event the surge block is moved too fast to allow the water to move at the same rate. Many different materials can be used, preferably of a rubbery consistency. The disks may be formed of natural or synthetic rubber, or from any of the thermoplastic elastomers such as polyolefins, nylons, polytetraflouroethylene, polyurethane and the like. The disks 16 and 18 must be stiff enough to effect movement of water in the well, so of course the thickness of the material will vary with the size of the well.
The body 15 of the surge block 14 will be made of a very durable material, such as stainless steel. Thus, the body 15 will be substantially permanent, while the disks 16 and 18 will be somewhat expendable. To hold the disks in place, and to render them easily changeable, the disk (for example, disk 18) is placed against the lower end of the body 15. A rigid plate 28 is placed over the disk 18, and a plurality of screws 29 is passed through the plate 28, through the disk 18, and into threaded holes in the body 15. This is well shown in FIGS. 2 and 3 of the drawings.
The disk 16 is similarly fixed to the top of the body 15. The only difference is that one of the screws 29 may be replaced by the screw eye 20. Obviously, the eye 20 may be provided in other ways, but use of a screw eye in place of one of the screws 29 is efficient and effective.
With the above discussion in mind, operation of the apparatus of the present invention should be understandable. When a well is to be cleaned, the tool of the present invention can be lowered into the well casing as shown in FIG. 1 of the drawings. As a preliminary step, the jetting tool 21 may be used to spray a chemical mix against the well screen for partially breaking up the clog on the screen. The jetting tool 21 will have openings such that fluid emitted therefrom will be dispersed, so there will a considerable amount of turbulence. This turbulent flow of fluid will cause significant agitation and cleaning of the well screen.
After the well screen has been at least partially cleaned, the tool of the present invention can be moved up and down to cause a surging action in the well. The reciprocating flow of the water will mechanically loosen further clogging material. It is also possible that the chemical introduced through the jetting tool 21 may assist in loosening the clog; therefore, one might introduce additional fluid during the surging so both the surging and jetting are utilized simultaneously.
Attention is next directed to FIG. 4 of the drawings for a discussion of some modifications of the invention. FIG. 4 illustrates several structural modifications of the well cleaning tool, but those skilled in the art will realize that any particular modifications may be used as needed for any particular well, with no requirement to adopt all the changes shown.
First, it is an existing practice to use more than two disks, such as the disks 16 and 18, on a surge block. While it is convenient to fix the disks 16 and 18 to the ends of the block 15, it will be understood that such disks may be fixed elsewhere. For example, a disk 16A may be fixed to the rigid conduit 19. Such disk may replace the disk 16 as is shown in full lines, or may be in addition to the disk 16 as is shown in phantom. Furthermore, a disk 18A may be added below the disk 18. As here illustrated, the disk 18A is carried by the jetting tool 21, but the disk may of course be fixed to the conduit 26, on either side of the jetting tool 21.
Those skilled in the art will understand that any number of disks may be used; and, the disks can be more or less flexible as described, and smaller or larger relative to the size of the well casing. These are variables that are routinely dealt with by those skilled in the art, and no further discussion is thought to be necessary.
It was previously mentioned that some structure other than the screw eye 20 can be used to support the surge block of the present invention. One alternative is shown in FIG. 4 where it will be seen that a bail 30 is fixed to a fitting 31. As here shown, the fitting 31 is received on the rigid conduit 19, and allows connection of a flexible hose 32. This same fitting is here shown as receiving the disk 16A, though it will be recognized that different mechanical devices may be used for the various functions if desired. It will be well understood that the control cable 34 may be fixed to the cleaning tool in many different ways, and the arrangements here shown are merely by way of illustration.
FIGS. 1 and 2 of the drawings show the jetting tool extending from the bottom of the cleaning tool for general use. There are times, however, when one may wish to confine the action of the jetting tool; and, the device of the present invention allows such confinement by selectively placing the jetting tool between two of the disks, such as the disks 16 and 18. For example, as shown in FIG. 4 the jetting tool 21 is below the disk 18, but above the disk 18A, so the tool 21 is confined between the two disks. As a result, the discharged fluid, and the turbulent action of the fluid, will be substantially confined between the two disks for a localized action.
Another means for achieving the confined jetting action is to provide jetting nozzles within the body 15 of the tool. FIG. 4 illustrates a plurality of radially-extending holes 35 in the body 15. Such holes will communicate with the central passage 22, and direct fluid outwardly, but confined between the disks 16 and 18, or the disks 16A and 18, or otherwise as desired.
As is stated above, it is generally preferable to provide a diverse fluid stream from the nozzle 21 or 35 since the usual intent is to clean the casing, well screen or the like. There are situations, however, wherein a more narrowly defined jet is useful. In wells wherein the well is drilled into a natural rock formation, and there is no artificial gravel pack, but simply naturally occurring rock appropriately fractured to allow the flow of liquid, it may be necessary to force fluid into the pores, or fractures, in the rock. For this purpose, the holes, the nozzle 21 or 35 may be closer to the well screen, and/or may be differently formed to provide a narrow jet of fluid.
With the above described structural modifications in mind, it will be understood that the apparatus of the present invention can be quite versatile. In addition to treating and cleaning wells having the gravel pack, the more narrowly confined jets can be used to drill out pores or fractures in a natural rock well, or fractured aquifer. Such wells are also referred to as a "open hole" or "rock" wells. Such cleaning, or drill-out, can be done with an open nozzle such as the jetting tool 21 shown in FIG. 1, or the nozzle can be confined between two disks as shown in FIG. 4.
In addition to cleaning old wells that have become fouled, the method and apparatus of the present invention can be used to develop new wells. Again, if the fracture, or pores, in rock must be cleaned or opened, the jetting action provided by the present apparatus can be used. The nozzle can be open, or confined; and, the jetting can be used either alone or in combination with surging.
While certain combinations are here illustrated, it will be understood that the various structures can be used alone, or in any combination deemed useful for the given problem. The specific structural arrangements herein illustrated and described are merely suggestive.
It will therefore be understood by those skilled in the art that the particular embodiments of the invention here presented are by way of illustration only, and are meant to be in no way restrictive; therefore, numerous changes and modifications may be made, and the full use of equivalents resorted to, without departing from the spirit or scope of the invention as outlined in the appended claims. | A well cleaning tool includes a surge block, and a jetting tool or nozzle carried by the surge block. The surge block has fluid passageways therein for supplying the jetting nozzle. The surge block is formed of a cylindrical central body with elastomeric disks fixed above and below the central body, the disks being sized to fit relatively snugly within the well casing. The fluid passageway through the central body is threaded at the top for connection of a supply conduit, and may be threaded at the bottom for connection of a jetting nozzle. Thus, the jetting tool can be used for initial cleaning, while the surge block confines the heat and chemical action; then, the surge block can be reciprocated for surging the well. Both surging and jetting can be used simultaneously, and/or alternatively. A plurality of disks can be used as desired, and a jetting nozzle can be outside the disks, or between two disks to confine the chemical action. | 4 |
This invention relates generally to instrument panels for automotive vehicles of the type having a retainer panel formed with an airbag deployment opening and a separately formed deployment door installed in the opening and covered by a continuous foam and skin layer and, more particularly, to the means of controlling foam leakage past the door during manufacture of the instrument panel.
BACKGROUND OF THE INVENTION
In manufacturing instrument panels of the above type, the separately formed door is typically hinged along one edge to the retainer and a gap exists along the remaining edges to provide clearance for installation and opening. The overlying foam layer is foamed in place in the space provided between the outer skin layer and an upper surface of the door and retainer members.
According to known practice, the gap between the door and retainer is masked off with adhesive tape after the door has been installed in the opening. The tape is applied to the outer surfaces of the door and retainer members across the gap and serves to block the foam material from leaking past the door. Application of such tape, although effective, adds an extra step in the manufacturing process and further presents a barrier to the direct adhesion of the foam material to the door and retainer members in the region of the masked areas.
An air bag closure assembly according to a method and construction of the invention overcomes and greatly minimizes the foregoing objections.
SUMMARY OF THE INVENTION
An instrument panel closure assembly for an air bag system of a vehicle according to the invention comprises a rigid retainer member having a top surface and a preformed air bag deployment opening surrounded at least in part by a retainer ledge recessed below the top surface. At least one separately formed door member is accommodated in the deployment opening of the retainer member and supported by the recessed retainer ledge against movement inwardly of the retainer ledge. A continuous outer flexible polymeric skin layer is spaced in overlying relation to the retainer and door members, between which an intermediate layer of foam material is foamed in place. A foam blockage seal is provided at the interface between the door member and the recessed ledge of the retainer member and is operative to block the passage of foam layer material past the door member and ledge during the formation of the foam layer.
The foam blockage seal may be formed as an integral part of the ledge and/or door or may be formed separately and applied to the ledge before installation of the door. The recessed seal eliminates the need for surface-applied masking tape and in doing so promotes complete, uniform direct adhesion of the foam layer to the underlying door and retainer members.
These and other features and advantages of the invention will become readily apparent when considered in connection with the following detailed description and drawings.
THE DRAWINGS
Presently preferred embodiments of the invention are disclosed in the following description and in the accompanying drawings, wherein:
FIG. 1 is a fragmentary perspective view of an interior instrument panel trim component constructed according to the invention;
FIG. 2 is a fragmentary plan view of such trim component showing the outer skin and foam layer broken away to expose the underlying door and retainer members;
FIG. 3 is an enlarged cross-sectional view taken along lines 3--3 of FIG. 1;
FIG. 4 is an enlarged cross-sectional view illustrating a preferred method of fabricating the trim component according to the invention; and
FIGS. 5-8 are each enlarged fragmentary cross-sectional views illustrating alternative sealing arrangements of the invention.
DETAILED DESCRIPTION
Referred now to FIGS. 1-3, an interior instrument panel trim component assembly 10 is illustrated concealing an air bag assembly 14 of known type.
The assembly 10 includes a retainer member 16 constructed as a rigid plastic or metal panel having a top surface 18 and a preformed deployment opening 20 normally closed by a separately formed door member 22. While in the illustrative embodiment the assembly 10 has a single door member 22, it will be appreciated that the invention is applicable and contemplates multiple door arrangements, such as that disclosed in U.S. Pat. No. 5,451,075, which is commonly owned by the assignee of the present invention and its disclosure incorporated herein by reference.
The opening 20 of the retainer 16 is generally rectangular and framed on three sides thereof by an integral ledge 24 recessed below the top surface 18 of the retainer 16. As illustrated best in FIG. 3, the ledge 24 has a generally L-shaped cross section including a downwardly depending side wall 30 and a transverse support wall 32 having an upper surface 34 generally parallel to but spaced from the top surface 18 of the retainer member 16.
The ledge 24 underlies corresponding side 25 and rear 26 edge regions of the door 22 (with respect to their relative positions in relation to the front and rear of the vehicle) supporting the door 22 against movement inwardly of the retainer and a top surface 28 of the door 22 aligned preferably flush with the top surface 18 of the retainer 16. Alternatively, the top surface 28 of the door 22 may be raised above the top surface 18 of the retainer 16, or the top surface 28 of the door 22 may be subflush with the top surface 18 of the retainer 16.
A forward edge 36 of the door 22 is secured to an adjacent forward edge 38 of the retainer 16 by a separate hinge 40 having a generally S-shaped strap configuration with one leg 42 overlying the forward edge 36 of the door and the other leg 44 extending beneath the forward edge 38 of the retainer and secured to each by a plurality of spaced rivets 45, or the like.
The retainer and door members 16, 22 are covered by a cushioning foam layer 46 and an outer flexible, decorative shell or skin layer 48. The skin layer 48 is preferably formed of a thermoplastic polymer, such as polyvinyl chloride, thermoplastic urethane, or thermoplastic olefin, according to known manufacturing techniques but could also be a thermoset polymer such as thermoset urethane. The skin 48 has a weakened invisible seam 50 formed therein corresponding in location and shape to the unhinged marginal edges 26 of the door member 22 according to known techniques. The foam layer 46 is fabricated by known foam-in-place techniques and foam reactant materials, such as urethane foam, in the space 52 between the skin layer 48 and the top surfaces 18, 28 of the retainer and door members 16, 22.
FIG. 4 schematically illustrates the general technique for molding the foam layer 46. As shown, the preformed skin layer 48 is positioned topside down in a cavity 54 of a mold tool 56 shaped in accordance with the desired shape of the instrument panel 12. The assembled retainer and door members 16, 22 are inserted into the mold and supported in spaced relation to the outer skin 48 to provide the foam space 52. Suitable foam reactants are then introduced into the space 52 where they react, expand and cure to fill the space 52 and generate the foam layer.
According to the invention, a seal 60 is provided between the ledge 24 of the retainer member 16 and the confronting edges 26 of the door 22 to prevent the foam 46 from escaping or leaking past the door 22 and ledge 24. The seal is formed between the door member 22 and the ledge 24 upon installing the door 22 in the opening 20. The invention contemplates various seal arrangements between the ledge 24 and door 22, the first of which is illustrated in FIGS. 3 and 4, with additional embodiments shown in FIGS. 5-8.
Turning now specifically to FIGS. 3 and 4, the support wall 32 of the ledge 24 is shown formed with at least one and preferably a pair of raised inner 62 and outer 63 ribs that project above the upper surface 34 of the support wall 32. The ribs 62, 63 are spaced inwardly of the side wall 30 and spaced laterally with respect to one another to define open channels 64, 66 underlying the door 22 adjacent the side wall 30 and between the ribs 62, 63 respectively. The ribs 62, 63 run continuously along the ledge 24 and preferably are in contact or close proximity with the underside of the door member 22 along the unhinged sides of the door 22, such that the ribs 62, 63 together with the hinge 40 seal the space 52 against foam leakage beyond the ledge 24. The expanding foam 46 enters a peripheral clearance gap 68 between the side wall 30 of the ledge 24 and the edge of the door 22 and from there pass into the first channel 64 beneath the door 22. The channel 64 serves as a reservoir for the foam 46 and in some cases may completely contain the excess foam. The invention contemplates that small gaps or spaces may exist between the top of the ribs 62, 63 and the confronting surface of the door 22 due to imperfections, pressure buildup, or designed clearance, allowing some of the foam material 46 to pass from the outer channel 64 into the adjacent inner channel 66. In this way, the ribs 62, 63 cooperate with the door 22 to define a tortuous, constricted flow path (i.e. a labyrinth seal) for the foam as it passes between the door 22 and ledge 24, causing the foam to accumulate and be retained in one or both channels 64, 66. As foam flows through thin cross-sections as at gap 68 and small gaps between ribs 62, 63 and door 22, its viscosity tends to increase and limit foam leakage at the door/retainer interface defined at gap 68.
It is preferred that the ribs 62, 63 be formed integrally with the formation of the ledge 24, and as such they may be molded, stamped or cast as unitary projections rising above the top surface 28 of the ledge 24 to meet the underside marginal regions 26 of the door 22.
FIG. 5 illustrates an alternative embodiment of the foam blockage seal, in which like reference numerals are used to identify like parts, but are offset by one hundred. The construction of the foam seal 160 is the same as that of the first embodiment of FIGS. 3 and 4, except that an additional resilient strip or gasket 70 is provided in the channel 166 to block the passage of the foam material 146 beyond the gasket 70. The gasket 70 is formed of a resilient, compressible material such as rubber, elastomeric plastic, and synthetic foam. However, it should be understood that any natural or synthetic gasket material will suffice, depending upon a particular application.
In the preferred embodiment, the foam strip or gasket 70 extends continuously along the ledge 24 around all three unhinged sides of the door member 22, and further is adhered at least to the ledge and preferably to the door 22 as well by means of an adhesive carried on the facing top and bottom surfaces 72, 74 of the gasket 70.
The foam gasket 70 is strong enough to hold the door 22 and ledge 24 sealed, yet is separable upon deployment of the air bag 14 to allow the door member 22 to swing outwardly of the retainer member 16 during such deployment. According to a preferred construction, the adherence strength of the foam strip 70 exceeds its tear strength, such that the foam layer 70 is caused to tear in half upon deployment of the air bag 14 with one half of the foam strip 70 remaining adhered to the ledge 24 and the other separated half remaining adhered to and carried outwardly with the door member 22.
FIG. 6 illustrates another embodiment of the invention, wherein like features are referenced by like numerals, but offset by two hundred. The foam seal 260 of the FIG. 6 embodiment is identical to that described above with respect to FIG. 5 except that the FIG. 6 embodiment lacks the rib formations 62, 63 and has only the foam strip 270 adhered to the door 22 and ledge 24 members.
FIG. 7 illustrates a still further embodiment of the invention with like features referenced by like numerals offset by three hundred. The ledge 324 is molded with a rib 362 as described previously. The door 22 is molded with a corresponding channel or recess 78 aligned to nest with the rib 362 of the retainer member. As shown in FIG. 7, the interleaving rib 362 and channel 78 may be located inwardly from the edge of the door 322 and side wall 330 of the ledge 324 to provide a reservoir 80 for the foam material 346 functioning as a labyrinth seal like that of the channel 64 described previously with respect to the first embodiment of FIGS. 1-4.
FIG. 8 shows yet another embodiment of the foam blockage seal 460 wherein the support wall 432 of the ledge 424 is formed with a mounting channel 82 in which a resilient foam or rubber gasket 470 is installed to provide a seal between the ledge 424 and door 422. The gasket 470 in this embodiment has enlarged end regions or heads 84, 86 that reside above and below the channel 82 when the gasket 470 is installed therein. In this way, the gasket 470 can be installed with a snap-fit connection into the channel 82 for ease of assembly.
If desired, the rib and seal configurations of the prior embodiments can be formed on the door rather than the ledge to serve the same function.
Furthermore, while it is preferred that the ribs, seals and gaps therebetween be formed continuously around the sides and rear of a door, the invention also encompasses an arrangement wherein such seal structure is provided over at least part of such sides and rear.
The disclosed embodiments are representative of a presently preferred forms of the invention, but are intended to be illustrative rather than definitive thereof. The invention is defined in the claims. | An instrument panel of an automotive vehicle includes a rigid retainer preformed with an air bag opening and a recessed ledge extending about the opening. A separately formed door is installed on the opening and hinged to the retainer along one edge. The remaining three edges overlie the ledge to prevent inward movement of the door. The retainer and door are placed in a cavity of a mold tool in spaced relation to an outer skin and foam constituents are reacted therebetween to develop a foam layer. A foam seal is provided at the interface of the ledge and door to prevent the escape of foam past the ledge. | 1 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a novel reactive dyestuff with a N-alkylamino bridge group and, more particularly, to a novel reactive dyestuff suitable for exhaust dyeing, cold batch-up dyeing, continuous dyeing, printing and digital spray printing materials that contain hydroxyl group or polyamine fibers.
2. Description of Related Art
An azo dyestuff, where the chromophore thereof is composed of azo components and coupling components, can be widely employed and used as a reactive dyestuff for heavy color dyeing, such as red, navy, blue, black and so on, owing to its broad color gamut and high extinction coefficient.
Currently, the development of reactive dye is moving towards warm dyeing, higher fixation and better build up to meet the economic demands. Since sulphato-ethyl-sulphone (SES) reactive groups cannot meet customers' demands for cotton dyeing due to their poor resistance to alkaline, monochloro triazine (MCT) type dyestuffs are usually used for dyeing. However, the use of monochloro triazine (MCT) type dyestuffs in dyeing consumes more energy and the dyed materials exhibit poor water fastness.
For example, in U.S. Pat. Nos. 5,552,532, 5,931,975, 5,717,078, 5,837,827 and 5,831,038, such dyestuffs are developed.
However, the build up, hue-shift, levelness and wash fastness of the aforementioned novel dyestuffs cannot meet the market requirements. Thereby, it is desirable to improve the aforementioned properties.
SUMMARY OF THE INVENTION
The present invention provides a novel reactive dyestuff with a N-alkylamino bridge group, which exhibits the properties of improved fixation yield, excellent build up, high wash fastness and excellent wet fastness while dyeing cellulose fibers.
In the present invention, the novel reactive dyestuff with a N-alkylamino bridge group is represented by the following formula (I),
wherein, A 1 and A 2 each independently are selected from the group consisting of benzene, monoazo, disazo, polyazo and metal complex azo components;
X 1 and X 2 each independently are halogen, hydroxyl, quaternary ammonium or —NR 1 R 2 ;
R 1 , R 2 , R 3 and R 4 each independently are hydrogen, C 1-4 alkyl, C 1-4 alkylcarbonyl, phenyl, nitroso, or C 1-4 alkyl substituted by halogen, hydroxyl, carboxyl or sulfo;
(R 5 ) 0-2 and (R 6 ) 0-2 each independently are 0 to 2 identical or different groups, and each of R 5 and R 6 independently is selected from the group consisting of hydrogen, halogen, hydroxyl, carboxyl, sulfo, nitro, cyano, C 1-4 alkyl, C 1-4 alkoxy, ureido and amido;
(Z 1 ) 0-1 and (Z 2 ) 0-1 each independently are 0 to 1 reactive group, and each of Z 1 and Z 2 independently is selected from the group consisting of —SO 2 —U, —CONH—(CH 2 ) k —SO 2 —U, —O—(CH 2 ) s —CONH—(CH 2 ) t —SO 2 —U, β-thiosulfatoethylsulfonyl and —N(R′)—U′.
U is —CH 2 CH 2 W, —CH═CH 2 and —CH 2 CH 2 OH;
W is a leaving group eliminable by a base, which is —Cl, —OSO 3 H, —OPO 3 H, quaternary ammonium, pyridine, carboxypyridinium, methylpyridinium or carbonamidopyridinium;
U′ is α,β-halopropionyl, α-haloacryloyl, β-halopropionyl or α-haloacryloyl;
R′ is hydrogen or C 1-4 alkyl; and
k, n, s and t each independently are 2, 3 or 4.
In the reactive dyestuff of the formula (I) according to the present invention, A 1 and A 2 may each independently be a benzene component. Preferably, A 1 and A 2 each independently are represented by the following formula (* represents a position for connecting to an amino group),
wherein, (R 7 ) 0-3 is 0 to 3 identical or different groups, and each of R 7 independently is selected from the group consisting of halogen, hydroxyl, carboxyl, sulfo, amino, nitro, cyano, C 1-4 alkyl, C 1-4 alkoxy, C 2-6 alkoxycarbonyl, carbamoyl, C 2-5 alkanoylamino and C 2-5 alkylcarboxyl.
In the reactive dyestuff of the formula (I) according to the present invention, A 1 and A 2 may each independently be a monoazo component. Preferably, A 1 and A 2 each independently are represented by the following formulas (* represents a position for connecting to an amino group),
wherein, R 4 , (R 5 ) 0-2 , (R 6 ) 0-2 and (R 7 ) 0-3 are defined as above;
R 8 is hydrogen, C 1-4 alkyl, C 2-4 alkylcarboxyl or C 1-4 alkyl substituted by hydroxyl, cyano, acetyl, amido, carboxyl, sulfo, methoxycarbonyl, ethoxycarbonyl or acetoxy; and
R 11 is hydrogen, halogen, hydroxyl, carboxyl, sulfo, amino, nitro, cyano, acetylamino, ureido, C 1-4 alkyl and C 1-4 alkoxy.
In the reactive dyestuff of the formula (I) according to the present invention, A 1 and A 2 may each independently be a disazo component. Preferably, A 1 and A 2 each independently are represented by the following formulas (* represents a position for connecting to an amino group),
wherein (R 5 ) 0-2 , (R 6 ) 0-2 and (R 7 ) 0-3 are defined as above;
(R 9 ) 0-3 is 0 to 3 identical or different groups, and each of R 9 independently is selected from the group consisting of halogen, hydroxyl, carboxyl, sulfo, amino, nitro, cyano, C 1-4 alkyl, C 1-4 alkoxy, C 2-6 alkoxycarbonyl, carbamoyl, C 2-5 alkanoylamino and C 2-5 alkylcarboxyl; and
(R 10 ) 0-3 is 0 to 3 identical or different groups, and each of R 9 independently is selected from the group consisting of halogen, hydroxyl, carboxyl, sulfo, amino, nitro, cyano, C 1-4 alkyl, C 1-4 alkoxy, C 2-6 alkoxycarbonyl, carbamoyl, C 2-5 alkanoylamino and C 2-5 alkylcarboxyl.
In the reactive dyestuff of the formula (I) according to the present invention, A 1 and A 2 may each independently be a polyazo component. Preferably, A 1 and A 2 each independently are represented by the following formulas (* represents a position for connecting to an amino group),
wherein (R 7 ) 0-3 is defined as above; and p is 2 or 3.
In the reactive dyestuff of the formula (I) according to the present invention, A 1 and A 2 may each independently be a metal complex azo component. Preferably, A 1 and A 2 each independently are represented by the following formulas (* represents a position for connecting to an amino group),
wherein (R 7 ) 0-3 and R 11 are defined as above;
R 12 is hydrogen, halogen, hydroxyl, carboxyl, sulfo, amino, nitro, cyano, acetylamino, ureido, C 1-4 alkyl and C 1-4 alkoxy; and
(R 13 ) 0-3 is 0 to 3 identical or different groups, and each of R 7 independently is selected from the group consisting of halogen, hydroxyl, carboxyl, sulfo, nitro, cyano, C 1-4 alkyl, C 1-4 alkoxy, C 2-6 alkoxycarbonyl, carbamoyl, C 2-5 alkanoylamino and C 2-5 alkylcarboxyl.
In the reactive dyestuff of the formula (I) according to the present invention, A 1 and A 2 may each independently be a monoazo component. More preferably, A 1 and A 2 each independently are represented by the following formulas (* represents a position for connecting to an amino group),
wherein R 8 is defined as above; f, g and h are integers independent of one another between 0 to 2, and f+g+h is an integer between 0 to 3; and
x and y are integers independent of one another between 0 to 2, and x+y is an integer between 0 to 3.
In the reactive dyestuff of the formula (I) according to the present invention, A 1 and A 2 may each independently be a disazo component. More preferably, A 1 and A 2 each independently are represented by the following formulas (* represents a position for connecting to an amino group),
wherein x and y are defined as above.
In the reactive dyestuff of the formula (I) according to the present invention, A 1 and A 2 may each independently be a metal complex azo component. More preferably, A 1 and A 2 each independently are represented by the following formulas (* represents a position for connecting to an amino group),
For convenience in description, the compound is expressed as free acid in the specification. When produced or used, the dyestuffs of the present invention are often presented as water-soluble salts. The salts suitable for the present invention may be the alkaline metal salts, alkaline earth metal salts, ammonium salts or organic amine salts; preferably, the salts are sodium salts, potassium salts, lithium salts, ammonium salts or triethanolamine salts.
The dyestuffs according to the present invention can be prepared by a conventional method. The synthetic routine for preparing the dyestuffs is not strictly limited. For example, a chromophore may be first prepared and then a desired dyestuff is synthesized, or a chromophore may be synthesized in the process for preparing a dyestuff.
The dyestuffs of the present invention can be applied to dye and print many kinds of fiber materials, particularly cellulose fiber materials and cellulose-included fiber materials. The examples of the fiber materials are not limited. It can be natural or regenerated cellulose fibers, such as cotton, hemp, linen, jute, ramie, mucilage rayon, as well as cellulose-included fiber materials. The dyestuffs of the present invention can also be applied to dye and print fiber blended fabrics containing hydroxyl groups.
The dyestuffs of the present invention can be applied to the fiber material and fixed on the fiber in various ways, particularly in the form of aqueous dyestuff solutions and printing pastes. They can be applied to dye and print cellulose fibers by exhaustion dyeing, continuous dyeing, cold-pad-batch dyeing, printing or digital printing.
The dyeing or printing of the present invention can be proceeded by the conventional and usually known method. For example, exhaustion dyeing is applied by using separately or mixing the well-known inorganic salts (e.g. sodium sulfate and sodium chloride) and acid-binding agents (e.g. sodium carbonate, sodium hydroxide). The amount of inorganic salts and alkali does not matter. The inorganic salts and alkali can be added either once or several times into the dyeing bath through traditional methods. In addition, dyeing assistant agents (such as a leveling agent, suspending agent and so on) can be added according to conventional methods. The range of dyeing temperature is from 40° C. to 90° C. Preferably, the temperature for dyeing is from 50° C. to 70° C.
In the cold-pad-batch dyeing method, the material is padded by using the well-known inorganic salts (e.g. sodium sulfate and sodium chloride) and acid-binding agents (e.g. sodium carbonate, sodium hydroxide). The padded fabric is rolled and stored at room temperature to allow dye fixation to take place.
In the continuous dyeing method, two different methods exist. In the single-bath pad dyeing method, the material is padded according to the conventional method in the mixture of the well-known acid-binding agents (e.g. sodium carbonate or sodium bicarbonate) and the pad liquid. The resultant material is then dried and color fixed by baking or steaming.
In the two-bath pad dyeing method, the material is padded with a dye liquid and then dealt by a known inorganic neutral salt (e.g., sodium sulfate or sodium silicate). The dealt material is preferably dried and color-fixed by baking or steaming in the usual manner.
In the textile printing method, such as the single printing method, the material is printed by using printing paste containing the known acid-binding agent (e.g., sodium bicarbonate) and is dried and color-fixed by baking or steaming.
In the two-phase printing method, the material is dipped in a solution containing inorganic neutral salt (e.g., sodium chloride) and the known acid-binding agent (e.g., sodium hydroxide or sodium carbonate) in a high temperature of 90° C. or above to fix the color.
The dyeing or printing methods employed in the process of the present invention are not limited to the above methods.
Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
None.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
For convenience in the statement, the following examples are exemplified for a more concrete description. Many examples have been used to illustrate the present invention. The examples sited below should not be taken as a limit to the scope of the invention. The compounds are represented in the form of free acid. However, in practice, they often exist as metallic salts, and most likely alkaline metallic salts, particularly sodium salts. Unless otherwise stated, the parts and percentages used in the following examples are based on weight, and the temperature is in Celsius degrees (° C.).
EXAMPLE 1
(a) 18.8 parts of cyanuric chloride are dispersed in 200 parts of 0° C. water, followed by the addition of a solution containing 31.9 parts of 4-amino-5-hydroxy-2,7-naphthalenedisulfonic acid. Next, the pH value of the reaction solution is adjusted to a range of 1 to 3 by the addition of 15% Na 2 CO 3 (aq), and its temperature is maintained below 5° C. to perform reaction for 2 hours. Finally, the reaction solution is filtered and the filtrate is reserved.
(b) 28.1 parts of 4-(β-sulfatoethylsulfone) aniline and 25.6 parts of 32% HCl (aq) are added into 300 parts of 0° C. water with thorough stirring to form a dispersion solution, followed by the addition of 7.2 parts of sodium nitrite. The temperature of the solution is controlled in a range of 0° C. to 5° C. until the diazotization is accomplished. Subsequently, the above filtrate prepared in the step (a) is added therein, and the pH value of the reaction solution is adjusted to a range of 6 to 8 by the addition of Na 2 CO 3 . The reaction is performed for 3 hours to obtain a red product.
(c) To the above aqueous solution prepared in the step (b), 10.7 parts of 4-(2-(methylamino)ethylsulfonyl)aniline are added. Next, the pH value of the reaction solution is adjusted to a range of 7 to 9 by the addition of Na 2 CO 3 powder at a temperature of 20-35° C. After the reaction is accomplished, a red product of the formula (1) is obtained.
EXAMPLE 2
(a) 18.8 parts of cyanuric chloride are dispersed in 200 parts of 0° C. water, followed by the addition of 18.8 parts of 2,4-diaminobenzene-1-sulfonic acid powder. Next, the pH value of the reaction solution is adjusted to a range of 1 to 3 by the addition of 15% Na 2 CO 3 (aq), and its temperature is maintained below 5° C. to perform reaction for 2 hours.
(b) 36.1 parts of 1-aminobenzene-4-(b-sulfatoethyl sulfone)-2-sulfonic acid and 30 parts of 32% HCl (aq) are added into 150 parts of 0° C. water with thorough stirring, followed by the addition of 7.2 parts of sodium nitrite. The reaction solution is stirred until the diazotization is accomplished. Subsequently, the above solution prepared in the step (a) is added therein, and the pH value of the reaction solution is adjusted to a range of 6 to 7 by the addition of Na 2 CO 3 . The reaction is performed for 3 hours to obtain an orange product.
(c) To the above aqueous solution prepared in the step (b), 12.2 parts of 2-methoxy-5-(2-(methylamino)ethylsulfonyl)aniline are added. Next, the pH value of the reaction solution is adjusted to a range of 7 to 9 by the addition of Na 2 CO 3 powder at a temperature of 20-35° C. After the reaction is accomplished, an orange product of the formula (2) is obtained.
EXAMPLE 3
(a) 18.8 parts of cyanuric chloride are dispersed in 200 parts of 0° C. water, followed by the addition of a solution containing 31.9 parts of 4-amino-5-hydroxy-2,7-naphthalenedisulfonic acid. Next, the pH value of the reaction solution is adjusted to a range of 1 to 3 by the addition of 15% Na 2 CO 3 (aq), and its temperature is maintained below 5° C. to perform reaction for 2 hours. Finally, the reaction solution is filtered and the filtrate is reserved.
(b) 28.1 parts of 4-(β-sulfatoethylsulfone) aniline and 25.6 parts of 32% HCl (aq) are added into 300 parts of 0° C. water with thorough stirring to form a dispersion solution, followed by the addition of 7.2 parts of sodium nitrite. The temperature of the solution is controlled in a range of 0° C. to 5° C. until the diazotization is accomplished. Subsequently, the above filtrate prepared in the step (a) is added therein, and the pH value of the reaction solution is adjusted to a range of 6 to 8 by the addition of Na 2 CO 3 . The reaction is performed for 3 hours to obtain a red product.
(c) To the above aqueous solution prepared in the step (b), 12.2 parts of 2-(2-(4-aminophenylsulfonyl)ethylamino)ethanol are added. Next, the pH value of the reaction solution is adjusted to a range of 7 to 9 by the addition of Na 2 CO 3 powder at a temperature of 20-35° C. After the reaction is accomplished, a red product of the formula (1) is obtained.
EXAMPLES 4-27
According to the synthetic methods of Examples 1-3, the compounds (4)-(27) can be obtained, shown as follows.
Example
(Formula)
D
Ra
Rb
Rc
4
H
H
CH 3
5
H
H
CH 3
6
H
H
CH 3
7
H
H
CH 3
8
H
H
CH 3
9
H
H
CH 3
10
H
H
CH 3
11
H
H
CH 3
12
H
H
CH 3
13
H
H
C 2 H 4 OH
14
H
H
C 2 H 4 OH
15
H
H
C 2 H 4 OH
16
H
H
C 2 H 4 OH
17
H
H
C 2 H 4 OH
18
H
H
C 2 H 4 OH
19
H
H
C 2 H 4 OH
20
H
H
C 2 H 4 OH
21
H
H
C 2 H 4 OH
22
H
H
C 2 H 5
23
H
H
C 2 H 5
24
H
H
C 2 H 5
25
H
H
26
H
H
27
H
H
EXAMPLES 28-49
According to the synthetic methods of Examples 1-3, the compounds (28)-(49) can be obtained, shown as follows.
Rd
Re
Rf
Example
H
OCH 3
CH 3
(Formula)
D
28
29
30
31
Rd
Re
Rf
Example
C 2 H 5
H
CH 3
(Formula)
D
32
33
34
35
Rd
Re
Rf
Example
H
OCH 3
C 2 H 4 OH
(Formula)
D
36
37
38
39
Rd
Re
Rf
Example
C 2 H 5
H
C 2 H 4 OH
(Formula)
D
40
41
42
43
Rd
Re
Rf
Example
OCH 3
H
C 2 H 5
(Formula)
D
44
45
Rd
Re
Rf
Example
C 2 H 5
H
C 2 H 5
(Formula)
D
46
47
Rd
Re
Rf
Example
H
H
C 2 H 5
(Formula)
D
48
Rd_
Re
Rf
Example
OCH 3
H
0
(Formula)
D
49
EXAMPLE 50
(a) 9.4 parts of cyanuric chloride are dispersed in 100 parts of 0° C. water, followed by the addition of a solution containing 16 parts of 4-amino-5-hydroxy-2,7-naphthalenedisulfonic acid. Next, the pH value of the reaction solution is adjusted to a range of 1 to 3 by the addition of 15% Na 2 CO 3 (aq), and its temperature is maintained below 5° C. to perform reaction for 2 hours. Finally, the reaction solution is filtered and the filtrate is reserved.
(b) 14 parts of 4-(β-sulfatoethylsulfone) aniline and 12.8 parts of 32% HCl (aq) are added into 150 parts of 0° C. water with thorough stirring to form a dispersion solution, followed by the addition of 3.6 parts of sodium nitrite. The temperature of the solution is controlled in a range of 0° C. to 5° C. until the diazotization is accomplished. Subsequently, the above filtrate prepared in the step (a) is added therein, and the pH value of the reaction solution is adjusted to a range of 6 to 8 by the addition of Na 2 CO 3 . The reaction is performed for 3 hours to obtain a red product.
To the above aqueous solution prepared in the step (b), 12.2 parts of 2-(2-(4-aminophenylsulfonyl)ethylamino)ethanol are added. Next, the pH value of the reaction solution is adjusted to a range of 5 to 7 by the addition of Na 2 CO 3 powder at a temperature of 20-35° C. After the reaction is accomplished, a red product of the formula (50′) is obtained.
(a) 9.4 parts of cyanuric chloride are dispersed in 100 parts of 0° C. water, followed by the addition of a solution containing 16 parts of 4-amino-5-hydroxy-2,7-naphthalenedisulfonic acid. Next, the pH value of the reaction solution is adjusted to a range of 1 to 3 by the addition of 15% Na 2 CO 3 (aq), and its temperature is maintained below 5° C. to perform reaction for 2 hours. Finally, the reaction solution is filtered and the filtrate is reserved.
(b) 15.6 parts of 2-aminoanisole-4-vinyl sulfone and 12.8 parts of 32% HCl (aq) are added into 150 parts of 0° C. water with thorough stirring to form a dispersion solution, followed by the addition of 3.6 parts of sodium nitrite. The temperature of the solution is controlled in a range of 0° C. to 5° C. until the diazotization is accomplished. Subsequently, the above filtrate prepared in the step (a) is added therein, and the pH value of the reaction solution is adjusted to a range of 7.5 to 8.5 by the addition of Na 2 CO 3 . After the reaction is accomplished, the pH value of the reaction solution is adjusted to a range of 5 to 6 by the addition of 32% HCl (aq) to obtain a red product of the formula (50).
EXAMPLES 51-55
According to the synthetic method of Example 50, the compounds (51)-(55) can be obtained, shown as follows.
Example
(Formula)
R′ (CH 3 )
51
Da
Db
52
Da
Db
53
Da
Db
Example
(Formula)
R' (C 2 H 4 OH)
54
Da
Db
55
Da
Db
TESTING EXAMPLE 1
One part of the dyestuff prepared in Example 1 is dissolved in 100 parts of distilled water to prepare a dye solution. Twenty parts of the dye solution are poured into a dyeing vessel. Subsequently, 4.8 parts of Glauber's Salt are added into the dyeing vessel and then distilled water is added therein to make up the total amount of the dye solution to be 75 parts in total. After that, 5 parts of 320 g/l soda ash are added to the dyeing vessel. Four parts of woven cotton fabric are put into the dye solution, followed by covering and locking the dyeing vessel, and the dyeing vessel is shaken to survey the dye. Then, the dyeing vessel is put into a thermostatic bath, followed by switching on the rotating knob. The temperature is raised to 60° C. in 30 minutes and then kept for 60 minutes. After dyeing is accomplished, the dyed fabric is taken out and washed with cold water. Finally, after washing, dehydration and drying, a red fabric with good build up and good tinctorial yield is obtained.
TESTING EXAMPLE 2
Three parts of the dyestuff prepared in Example 1 are dissolved in 100 mL of water to obtain a 30 parts/1 padding liquor. Twenty-five ml of alkali solvent (taking 15 ml/l of NaOH and 30 parts/1 of Glauber's salt) is added to the padding liquor and stirred thoroughly. The resultant solution is then put into a pad roller machine. The cotton fabric is padded by the roller pad machine, and batched for 4 hours at room temperature. The obtained red fabric is sequentially washed with cold water, boiling water for 10 minutes, boiling non-ionic detergent for 10 minutes, again with cold water and then dried to obtain a red fabric with good build up and good tinctorial yield.
TESTING EXAMPLE 3
One hundred parts of Urea, 1 part of m-nitrobenzene sulfonic acid sodium salt, 20 parts of sodium bicarbonate, 55 parts of sodium alginate, and 815 parts of lukewarm water (1000 parts in total) are stirred in a vessel to obtain a completely homogeneous printing paste.
Three parts of the dyestuff prepared in Example 10 are sprayed in 100 parts of the above printing paste and stirred to make a homogeneous colored paste. An adequate size piece of twilled cotton fabric is covered with a 100 mesh 45°-twilled printing screen and then painted with the colored paste on the printing screen to give a colored fabric.
This colored fabric is placed in an oven at 65° C. for 5 minutes until dry and then put into a steaming oven using saturated steam of 102-105° C. for 10 minutes.
The obtained red fabric is sequentially washed with cold water, boiling water for 10 minutes, boiling non-ionic detergent for 10 minutes, again with cold water and then dried to obtain a red fabric with good build up and good tinctorial yield.
Accordingly, the technology according to the present invention achieves the objects of the invention and conforms to the patent requirements of novelty, inventive step and industrial applicability. Although the present invention has been explained in relation to its preferred examples, it is to be understood that many other possible modifications and variations can be made without departing from the scope of the invention as hereinafter claimed. | The present invention relates to a novel reactive dyestuff with a N-alkylamino group, represented by the following formula (I):
wherein A 1 , A 2 , R 1 , R 2 , R 3 , R 4 , (R 5 ) 0-2 , (R 6 ) 0-2 , (Z 1 ) 0-1 , (Z 2 ) 0-1 , X 1 , X 2 and n are defined the same as the specification. The reactive dyestuff of the present invention is suitable for exhaust dyeing, cold batch-up dyeing, continuous dyeing, printing and digital spray printing materials that contain hydroxyl group or amino group fibers. | 2 |
BACKGROUND OF THE INVENTION
[0001] The invention relates to decontamination. More particularly, the invention relates to decontamination against chemical and biological agents.
[0002] Well developed fields exist regarding the decontamination of areas contaminated with chemical and biological agents. Various techniques involve thermal decontamination. Some are typically useful for decontaminating thermally robust contaminated locations such as the exposed surfaces of a military vehicle. For example, U.S. Pat. No. 4,551,092 to Sayler discloses a jet engine decontamination system. In such a system, the jet exhaust is directed to the contaminated surfaces and heats them sufficiently to decompose chemical agents and kill biological agents. Various such systems are vehicle-mounted permitting the jet exhaust to be controllably swept over the surfaces to be contaminated.
[0003] More recently, concerns regarding laboratory and factory accidents, bio-terrorism, and the like encouraged development of principally chemical decontamination systems for decontaminating less robust (and often larger) locations. For example, the interior of an entire building or a portion thereof (e.g., a room) may need to be decontaminated. Exemplary chemical decontamination systems have typically involved use of chlorine (e.g., chlorine dioxide). However, use of chlorine dioxide raises certain safety considerations. Accordingly, use of hydrogen peroxide vapor for decontamination has been proposed. International Patent Publication WO 02/066082 of Steris, Inc. et al. discloses a flash vaporizer for providing antimicrobial hydrogen peroxide. Chemical systems may also be used in direct spray modes in lieu of the thermal systems. For example, it has been proposed to use a chemical system for the in situ decontamination of jet aircraft engines.
[0004] Separately, catalytic systems have been developed to decompose hydrogen peroxide into water and oxygen (e.g., to provide oxygen for use in rocket propulsion). For example, U.S. Pat. No. 6,532,741 to Watkins and U.S. Pat. No. 6,652,248 to Watkins et al. disclose such catalytic systems.
SUMMARY OF THE INVENTION
[0005] One aspect of the invention involves a decontamination method. At least a first flow of hydrogen peroxide is directed to a catalytic reactor. The first flow is passed through a catalyst so as to decompose at least a portion of the first flow into water and oxygen. A discharge flow of the water and oxygen and additional hydrogen peroxide is directed to a contaminated location so as to provide a decontamination.
[0006] Another aspect of the invention involves a decontamination apparatus. A vessel contains a supply of hydrogen peroxide. A catalytic reactor is coupled to the vessel to receive a first flow and at least partially decompose hydrogen peroxide from the first flow into decomposition products. An outlet is positioned to direct a discharge flow containing the decomposition products and undecomposed hydrogen peroxide to a contaminated location.
[0007] The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a schematic view of a first decontamination system.
[0009] FIG. 2 is a schematic view of a second decontamination system.
[0010] FIG. 3 is a schematic view of a third decontamination system.
[0011] FIG. 4 is a schematic view of a fourth decontamination system.
[0012] FIG. 5 is a schematic view of a fifth decontamination system.
[0013] FIG. 6 is a longitudinal cross-sectional view of a catalyst bed assembly of a decontamination system.
[0014] FIG. 7 is a cross-sectional view of an outer housing of the catalyst bed assembly of FIG. 6 .
[0015] FIG. 8 is a detailed cross-sectional view of a downstream end portion of the catalyst bed assembly of FIG. 6 .
[0016] FIG. 9 is a longitudinal cross-sectional view of an alternate catalyst bed assembly.
[0017] Like reference numbers and designations in the various drawings indicate like elements.
DETAILED DESCRIPTION
[0018] A catalytic decomposition system may decompose a first hydrogen peroxide flow or portion thereof and help drive an additional non-decomposing hydrogen peroxide flow or portion for decontamination. FIG. 1 shows a first exemplary decontamination system 20 mounted on a vehicle 22 (e.g., a self-propelled or towed wheeled or tracked vehicle). The system 20 delivers an output/discharge flow or stream 24 (e.g., essentially a gaseous mixture) containing a quantity of hydrogen peroxide effective for decontamination use. The exemplary system 20 includes a vessel (e.g., a tank) containing a relatively high concentration of hydrogen peroxide (e.g., in excess of a 70% solution (weight percent unless noted), more advantageously in excess of a 90% solution, and most advantageously in excess of a 95% solution, such as an approximately 98% solution). The hydrogen peroxide is delivered through a conduit 30 to a catalytic reactor 32 . This flow from the tank may be a blow-down flow caused by a pressurant gas (e.g., nitrogen). An exemplary pressurant gas is stored in a separate vessel or tank 34 coupled to a headspace of the tank 26 via a conduit 36 . Valves (not shown) may control the flow through the conduits 30 and 36 and may be actuated by a control system (also not shown). The reactor 32 and/or an outlet therefrom may be capable of orientational and/or positional changes such as via an actuator system 40 (e.g., electromechanical, hydraulic, or pneumatic) to permit aiming of the stream 24 such as for sweeping a discharge pattern over a larger area to be contaminated.
[0019] The catalytic reaction in the reactor 32 converts just a portion of the hydrogen peroxide delivered to the reactor. For example, with a reactor input flow of 98% hydrogen peroxide, sufficient hydrogen peroxide may be decomposed into water vapor and oxygen that the discharge stream 24 will have a hydrogen peroxide content of approximately 35% (at a temperature of about 260° C. (500° F.) compared with about 950° C. (1750° F.) for full decomposition). The decomposition releases energy which heats and further expands the reaction products (in addition to the 50% molar expansion). The expansion may substantially drive the stream 24 including the entrained unreacted hydrogen peroxide. A broader range of the percentage of the hydrogen peroxide which may be decomposed may result in an output stream having 10-75% hydrogen peroxide. A narrower range is 15-35%. An exemplary temperature of the stream 24 is 170-280° C. (800-1000° R). An exemplary flow rate may depend upon the particular application (e.g., 0.05-9 kg/s). With a system sized for decontaminating typical military vehicles, an exemplary flow rate may be in the range of 1-3 kg/s. An exemplary system for open area decontamination may have a rate of 2-5 kg/s per reactor. An exemplary reactor is self-heating due to the catalytic reaction and thus lacking external heating (e.g., electric) at least during post-start-up conditions. An external start-up preheater for the reactor is an option.
[0020] As noted above, the stream 24 may be directly against a surface to be decontaminated or may be directed for area decontamination (e.g., of a field, street, and the like). An alternate open air use is more of a point defense operation with the stream 24 directed against an incoming cloud of biological or chemical warfare agent or counterstream against an incoming stream of such agent.
[0021] FIG. 2 shows another application wherein such a system 50 is mounted in an aircraft 52 having a fuselage 54 . In an exemplary manned fixed-wing aircraft having a main wing 56 bearing engine nacelles 58 , the hydrogen peroxide and pressurant tanks 60 and 62 may be contained within the fuselage. A conduit network 64 extends from the hydrogen peroxide tank to a number of separate reactors 66 mounted along the wing (either externally or internally) and discharging streams 68 . The streams may be discharged in a generally downward direction for area decontamination (e.g., of open fields or other outdoor areas). An exemplary number of separate reactors is 2-8 with at least one on each of the port and starboard sides of the wing. Unmanned and rotary wing aircraft are alternate platforms as are less integrated systems (e.g., substantially externally mounted systems).
[0022] FIG. 3 shows a system 80 for decontaminating an enclosed area 82 (e.g., one or more rooms within a building 84 ). The system may be mounted on a self-propelled or towed wheeled or tracked vehicle 86 and may include pressurant and peroxide tanks 88 and 90 and a reactor 92 similarly connected as those of the system 20 . In the illustrated embodiment, rather than directly discharging an airborne stream, the reactor is coupled to a discharge conduit network 94 which may include several branches terminating in several nozzles 96 discharging respective streams 98 . These nozzles may be configured to distribute relatively diffuse (e.g., omnidirectional) gaseous streams 98 . The individual nozzles may be located in separate rooms, a common room, or may be coupled to a building HVAC system providing distribution of the hydrogen peroxide. In another variation, multiple reactors remote of the vehicle could replace the multiple nozzles in a plumbing arrangement similar to that of the system 50 . In yet another arrangement wherein the vehicle is sufficiently small (e.g., a hand-movable cart) the vehicle may be brought into the building or room to be decontaminated. Relatively small flow rates may be appropriate for decontamination of confined internal spaces. The confinement retains the hydrogen peroxide for a duration after the flow is shut-off thereby increasing effectiveness. For example, to decontaminate the interior of a vehicle such as an armored vehicle or an ambulance, a much smaller amount is required than to decontaminate the exterior. For such an internal vehicular decontamination, a flow rate of about 0.02-0.1 kg/s for a period of about 5-10 s could substantially fill the interior space. With the vehicle sealed, the hydrogen peroxide could largely persist for a period of 5-10 minutes or longer to provide the effective decontamination.
[0023] FIG. 4 shows the system 80 being used to decontaminate the engine(s) of an aircraft 100 . The conduit network 94 is positioned to discharge the hydrogen peroxide streams into one or more engine intakes (inlets) 102 forcing the hydrogen peroxide through the engine and ultimately out an engine exhaust nozzle 104 . This may be performed while the engine is not running (although its spools may be fixed or rotating (e.g., induced by the hydrogen peroxide flow)). In such a system, the nozzle(s) may be mounted to a temporary cover placed over the engine intake(s) or one or more ducts may engage the intake(s) to guide the discharge flow.
[0024] FIG. 5 shows a system 120 aboard a ship 122 . The system 120 may have one or more central hydrogen peroxide and pressurant tank groups feeding one or more central and/or remote reactors 124 (directly or via additional conduits) discharging streams 126 to decontaminate exposed surfaces of the ship.
[0025] Suitable reactors may be formed in a variety of ways. One example is the catalyst bed assembly of Watkins et al. noted above (the disclosure of which is incorporated by reference herein as if set forth at length). With such a system, the portion of the hydrogen peroxide flow to be decomposed may pass through the catalyst bed while a remaining portion passes around and cools the catalyst bed and/or a housing. Alternatively, or in combination, the catalyst bed may be relatively undersized (e.g., so as to not decompose substantially all the hydrogen peroxide passing through the catalyst bed). Exemplary catalysts include: silver (e.g., formed as a screen or screen plating); and silver-based alloys. However, any catalyst that is useful in decomposing the hydrogen peroxide could be used.
[0026] FIG. 6 shows details of a catalyst bed assembly 200 taken from Watkins et al. The catalyst bed assembly 200 includes a catalyst bed section 201 and a nozzle section 203 . The nozzle section 203 secures to the catalyst bed section 201 with suitable fasteners 205 . As an example, the catalyst bed section 201 has an inner diameter of approximately 10 cm when dimensioned for an exemplary use in a medium flow rate application such as building interior decontamination.
[0027] The nozzle section 203 resides at the downstream, or outlet, end of the catalyst bed 201 . The nozzle 203 receives the discharge from the catalyst bed section 201 . The nozzle accelerates the discharge from the catalyst bed section 201 to form the exhaust stream (e.g., 24 et al.). Although shown as a convergent-divergent nozzle, other outlet structures are possible.
[0028] The nozzle section 203 can have threaded openings 229 for securing to any downstream component (e.g., the conduit assemblies 64 et al.). Also, the nozzle section 203 could be made from any suitable material, such as a high temperature, non-catalytic aerospace alloy.
[0029] The catalyst bed section 201 includes a catalyst can (cannister) 221 within an outer housing 207 . The outer housing 207 can be a cylindrical pipe having flanges 209 and 211 to secure the catalyst bed section 201 to other components (e.g., the associated vehicle, aiming actuators, or the like). However, other arrangements are possible. The outer housing 207 could be made from any suitable material, such as a high temperature, non-catalytic aerospace alloy.
[0030] The exemplary outer housing 207 secures to the nozzle section 203 using fasteners 205 . The flange 211 may include an annular groove 225 within which a C-shaped (in cross-section) annular metal seal 227 resides. The seal 227 keeps the hydrogen peroxide from escaping from the joint between the catalyst bed section 201 and the nozzle section 203 . Although described as a metallic C-shaped annular seal, any suitable seal or sealing arrangement could be used.
[0031] The exemplary outer housing 207 includes a threaded opening 213 in an upstream face 215 . The opening receives a correspondingly threaded coupling 217 to create an inlet. The coupling 217 secures to the supply conduit (e.g., 30 et al., shown in phantom in FIG. 6 ) supplying hydrogen peroxide to the catalyst bed assembly 200 .
[0032] The exemplary outer housing 207 includes an open interior 219 . The open interior 219 has a suitable size to receive the catalyst can 221 . The exemplary outer housing 207 has an annular shoulder 231 ( FIG. 7 ) in which a portion of the catalyst can 221 rests. The outer housing 207 also may have at least one threaded opening 233 for securing the catalyst can 221 on the shoulder 231 with a suitable fastener (not shown).
[0033] A first pressure baffle 223 resides within the open interior 219 of the outer housing 207 . The pressure baffle 223 is preferably made from a high temperature, non-catalytic aerospace alloy. The baffle 223 has an array of openings 239 therethrough. Exemplary openings 239 have a diameter of approximately 1-2 mm. However, other sizes, numbers and arrangements of the apertures could be used to achieve a suitable result. A ring 235 placed in an annular groove 237 on the inner surface of the outer housing 207 retains the pressure baffle 223 within the outer housing 207 .
[0034] The baffle 223 reduces the pressure of the liquid hydrogen peroxide in the direction of flow. In other words, the pressure of the hydrogen peroxide downstream of the baffle 223 is less than the pressure of the hydrogen peroxide upstream of the baffle.
[0035] As will be described in more detail below, in the exemplary embodiment, neither the outer housing 207 nor the nozzle section 203 require any cooling lines to manage the heat generated in the catalyst can 221 during decomposition of the hydrogen peroxide. Rather, a bypass flow of hydrogen peroxide (i.e., hydrogen peroxide that does not enter the catalyst bed) may cool the outer housing 207 and the nozzle section 203 .
[0036] The catalyst can 221 is preferably made from a suitable material, such as a high temperature, non-catalytic aerospace alloy. The exemplary catalyst can 221 has a cylindrical outer wall 241 ( FIG. 8 ) and downstream end flange 243 . The flange 243 includes a plurality of bypass apertures 245 .
[0037] The interior of the exemplary catalyst can 221 has an annular groove 247 ( FIG. 6 ) adjacent the upstream end. The groove 247 receives a metal ring 249 . The downstream end of the catalyst can 221 includes an annular internal shoulder 251 . The contents within the catalyst can 221 are retained between the metal ring 249 and the shoulder 251 and include: a second pressure baffle 253 ; a third pressure baffle 255 ; and catalyst material 257 forming a catalyst bed therebetween. The second pressure baffle 253 is located adjacent the ring 249 . The second pressure baffle 253 is also preferably made from a high temperature, non-catalytic aerospace alloy. The second pressure baffle 253 has an array of openings 259 therethrough. An exemplary baffle 253 has an outer diameter of approximately 7 cm and the openings 259 have a diameter of approximately 2.4 mm. However, other sizes, numbers and arrangements of the apertures 259 could be used to achieve a suitable result.
[0038] The ring 249 placed in the annular groove 247 retains the pressure baffle 253 in the catalyst can 221 . The baffle 253 serves to reduce the pressure of the liquid hydrogen peroxide in the direction of flow. In other words, the pressure of the hydrogen peroxide downstream of the baffle 253 is less than the pressure of the hydrogen peroxide upstream of the baffle.
[0039] The third pressure baffle 255 rests against the shoulder 251 . The third pressure baffle 255 is also preferably made from a high temperature, non-catalytic aerospace alloy. The third press baffle 255 has an array of openings 261 therethrough. Preferably, the baffle 255 has an outer diameter of approximately 7 cm and the openings 261 have a diameter of approximately 2 mm. However, other sizes, numbers and arrangements of the apertures 261 could be used to achieve a suitable result.
[0040] Once the nozzle section 203 is secured to the catalyst bed section 201 and the supply pipe of hydrogen peroxide is secured to the coupling 217 , the catalyst bed assembly 200 is ready to decompose the hydrogen peroxide. In an exemplary implementation, the supply of hydrogen peroxide enters the catalyst can 221 from the supply pipe with a diameter of approximately 8 cm at a flow rate of approximately 2-4 kg per second and a temperature of approximately 25° C. The catalyst material 257 decomposes the liquid hydrogen peroxide into water vapor, oxygen and heat. Other temperatures, flow rates and supply pipe sizes could be used to achieve a desired exhaust stream. Within the catalyst can 221 , a 98% hydrogen peroxide would decompose into water vapor and oxygen at approximately 6.9 MPa (1000 psi) and 945° C. (2192° R).
[0041] In order to withstand such high temperatures without using complex and heavy cooling schemes, the catalyst bed assembly 200 is designed so that a portion of the supply of hydrogen peroxide bypasses the catalyst can 221 . An annular gap/passageway 263 ( FIG. 8 ) exists between the outer housing 207 and the catalyst can 221 . The bypass liquid hydrogen peroxide fills and flows downstream through the annular gap 263 and serves to cool the catalyst can 221 . The liquid hydrogen peroxide in the annular gap 263 also limits heat build-up in the outer housing 207 . The exemplary annular gap 263 terminates at the downstream flange 243 of the catalyst can 221 . However, the bypass hydrogen peroxide, upon reaching the flange 243 , passes through the apertures 245 in the flange 243 . The amount of bypass could be controlled by the size of the annular gaps 263 , 265 , or by the number and the size of the apertures 245 .
[0042] Because the nozzle section 203 is likewise exposed to the heat created by the decomposition of the hydrogen peroxide in the catalyst can 221 , heat build-up in the nozzle section 203 should also be controlled. Similar to the annular gap 263 , a gap 265 ( FIG. 8 ) exists between the nozzle section 203 and the catalyst can 221 at the downstream end of the catalyst can 221 . Preferably, the liquid hydrogen peroxide provides film cooling along the interior surface of the nozzle section 203 while traveling through the nozzle section 203 .
[0043] FIG. 9 shows a catalyst bed assembly 300 wherein, relative to the assembly 200 , an intermediate mixing section 302 intervenes between the catalyst bed section 201 and the nozzle section 203 as disclosed in Watkins. The mixing section 302 includes concentric inner and outer housing sections 304 and 306 , respectively, defining an annular space/passageway 308 therebetween. The passageway 308 forms a continuation of the cooling passageway 263 . The exemplary mixing section facilitates the introduction of supplemental hydrogen peroxide flows 312 A and 312 B to mix with the flow 314 exiting the catalyst bed to dilute/cool that flow to form a diluted flow 316 which finally mixes with the cooling flow to form the discharge flow 318 . The exemplary flows 312 A and 3123 are expelled from apertures 320 in respective spray bars 322 A and 322 B. To feed the spray bars, the hydrogen peroxide feed conduit (e.g., 30 et al.) is split into branches, with branches 324 A and 324 B feeding the respective spray bars and a branch 324 C feeding the catalyst bed. Flow through each of the branches may be controlled via an associated valve (not shown) actuated by the control system (not shown). Flow rates through the various branches may, in view of any start-up or cool-down considerations, control the total flow rate and the discharge composition and temperature.
[0044] The introduction of the flows 312 A and 312 B downstream of the catalyst bed (and distinguished from the cooling flow portion passing through the gap) adds further variables which may be used to achieve a desired output. For example, if substantially all the hydrogen peroxide passing through the catalyst bed is decomposed then it is likely that the decomposition products will cause partial decomposition of the hydrogen peroxide from the flows 312 A and 312 B as the latter cool the flow 314 . To achieve a desired hydrogen peroxide concentration in the discharge flow 318 , the supplemental/bypass flows 312 A and 312 B, in combination, would represent a greater mass flow than the hydrogen peroxide in the discharge stream 318 . For example, in one implementation, approximately 95% of the third branch 324 C hydrogen peroxide flow enters the catalyst can as a first flow for decomposition by the catalyst material. The remaining 5% of the hydrogen peroxide bypasses and may cool the catalyst bed assembly and mixing section. Substantially all the first flow may be decomposed. The combined mass flow rates through the branches 324 A and 324 B could be an exemplary 1-5 times of that through the branch 324 C, more narrowly 2-3 times. About half or more of the hydrogen peroxide flowing through the branches 324 A and 324 B could decompose upon encountering the catalyst output flow 314 . Overall bypass to through-catalyst flow rates could be similar.
[0045] In operation, the hydrogen peroxide and pressurant tanks may need to be frequently refilled (e.g., after each mission for an airborne system, or a given number of uses for other systems). The catalyst can may need replenishment or replacement less frequently, if at all.
[0046] One or more embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. For example, various catalytic technologies may be adopted. Additionally, various system parameters may be tailored to particular applications. Accordingly, other embodiments are within the scope of the following claims. | Decontamination apparatus and methods involve catalytic decomposition of hydrogen peroxide to drive additional hydrogen peroxide to a contaminated location. | 0 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority to U.S. provisional patent application 61/179,644 filed on May 19, 2009 and U.S. provisional patent application 61/179,647 filed on May 19, 2009 under 35 U.S.C. 119(e). U.S. provisional patent application 61/179,644 and U.S. provisional patent application 61/179,647 are hereby incorporated by reference as though set forth in full.
BACKGROUND
1. Field of the Invention
The present invention relates generally to elliptical bikes, and particularly to guide tracks and features for elliptical bikes.
2. Related Art
U.S. Published Application 2008/0116655, which is incorporated by reference herein, discloses a self-propelled vehicle propelled by an elliptical drive train (hereinafter referred to as “elliptical bicycle”). In an elliptical bicycle, a user's feet are placed in foot platforms and the user strides forward and rearward, which though a variety of mechanical mechanisms, causes a rear wheel to rotate to propel the elliptical bicycle. The foot platforms, at a front end, are connected via foot links to respective load wheels that reciprocate along guide tracks of the bicycle frame. The load wheels must be secured to the guide tracks while also allowing relative reciprocating movement between the load wheels and the guide tracks/frame. In the past, additional coupling mechanisms have been provided to keep the load wheels on the guide tracks/frame; however, during some operations of the elliptical bicycle (e.g. when going over bumps), the load wheels may uncouple from the guide tracks/frame. Another problem that occurs is fast wear on the drive wheels and/or support surface of the guide tracks.
SUMMARY
An aspect of the invention involves an internal guide track system that ensures that the load wheels reciprocate efficiently along the guide tracks/frame while maintaining contact with the guide tracks/frame as part of a drive system that allows for a long stride length (>20 inches). An advantage of the internal guide track system is that it minimizes the likelihood that the forward end of the foot link will disengage with the frame and allows for a long stride length without the need for additional retention mechanisms.
The internal guide track system is comprised of one or more lower guide tracks and/or upper guide features contained inside of a tube or other hollow member which form the interface between the foot links and the frame of an elliptical bicycle. These upper guide features and lower guide tracks can be fixed elements of the internal guide track system/frame or they can be comprised of removable pieces that can be easily replaced throughout the life of the elliptical bicycle.
The upper guide features help to achieve a proper gap spacing between the drive wheels and the top of the internal guide track system over the lifetime of the elliptical bicycle. If there is too much space (i.e., too much gap spacing) between the drive wheels and the top of the internal guide track system, the drive wheels can “jump” the guidance features in the lower tracks and get stuck at an angle or rub against the sides of the guide track tubes. If the spacing is too tight, there will be too much contact/friction between the tops of the drive wheels and the top of the internal guide track system. Getting this gap spacing correct is complicated by the fact that the drive wheels wear down over the lifetime of the elliptical bicycle and, thus, the gap between the drive wheels and the top of the internal guide track system will continue to increase over time.
The upper guide features also include a low coefficient of friction contact surface to minimize friction when contacting the drive wheels.
The lower guide tracks and upper guide features serve to direct the forward ends of the foot links along a reciprocal path of travel. Some of the aspects of the lower guide tracks and upper guide features are: 1) they provide a guidance system for the foot link interface that enables an inexpensive, low friction, and simple interface to function effectively; 2) they provide an elegant method of ensuring that the foot links remain coupled to the frame during operation; 3) they can be made of or include a hard material such as steel or stainless steel or aluminum treated with a hard coating such as hard anodization or electroless nickel to improve resistance to wear; and 4) they can be modular and, therefore, can be easily replaced when worn. Each of these aspects is described in turn below.
1) Guidance system: The lower guide tracks are designed so that they have features that ensure the bearings at the end of the drive arms travel in a nearly straight line and are prevented from contacting the walls of the structural member.
2) Retention method: Because the foot links interface with the guide tracks inside of structural members, the foot links are retained onto the frame (and therefore prevented from disengaging with the frame) by the engagement between the frame member itself and the mechanism coupling the foot links to the guide tracks (usually one or more wheels, but also could be a ceramic bearing, etc.). As a result, unlike external track systems, an internal track system does not require an additional retention mechanism.
3) Hardness: Since they are or include a wear surface, the guide tracks and/or guide features can be made of or include a hard material or aluminum coated with a hard finish to improve the life of the guide tracks and minimize the aluminization of the mechanism coupling the foot links to the guide tracks that can occur during operation over bare aluminum. The guide tracks could also be made of a softer material such as plastic. This would insure that the majority of the wear in the sliding interface would occur to the lower guide tracks and not the foot link coupling mechanism. The plastic guide tracks would protect the structural frame from wear and could be cheaply and easily replaced throughout the life of the product.
4) Modularity: The lower guide tracks and/or upper guide features can be easily extracted from the elliptical bicycle and easily replaced with new guide tracks and/or guide features. Over time, friction caused by the interface of the guide tracks and or guide features and the foot link coupler will cause both the coupler and the guide tracks and/or guide features to wear. The modular system allows for the easy replacement of the guide tracks and/or guide features when they become worn or damaged. The modularity also enables the use of a hard or hard-coated material to be limited to the guide tracks and/or guide features only. If the guide tracks and/or guide features were not removable, then a larger structure would have to be made of the hard or hard-coated material adding cost and weight. The modularity could also enable the guide tracks and/or guide features to be made of a softer material such as a plastic. These softer guide tracks and/or guide features would insure that the majority of the wear would take place on the track side of the sliding interface and would preserve the life of the foot link couplers if they are made from a harder material. The plastic guide tracks and/or guide features would protect the structural frame from wear and could be cheaply and easily replaced throughout the life of the product.
Thus, the internal guide track system eliminates the need for an additional coupling mechanism to keep the foot links securely attached to the frame; allows for a sufficiently long stride length; maximizes the likelihood that the foot links will remain coupled to the frame and not disengage during operation; and modularity enables the easy replacement of worn guide tracks and/or guide features and allows for hard materials or coatings to be limited to the guide tracks and/or guide features exclusively, which are small surfaces, thereby minimizing cost and weight.
Another aspect of the invention involves an apparatus including a frame with a pivot axis defined thereupon; a drive wheel coupled to the frame; a first and a second foot link operably coupled to drive wheel to transfer power to said drive wheel so as to propel the apparatus, each including a foot receiving portion for receiving an operator's foot, a front end, and a rear end; and a pair of internal guide track systems coupled to the frame, each internal guide track system being operative to engage the front end of its respective foot link and to direct said front end along a reciprocating path of travel while providing retention to each foot link.
A further aspect of the invention involves an apparatus including a frame having a drive wheel rotatably supported thereupon, and a first pivot axis defined thereupon; a first and a second foot link, each having a front end, a rear end, and a foot receiving portion defined thereupon; a coupler assembly which is in mechanical communication with said pivot axis and with a rear end of each of said first and second foot links, said coupler assembly being operative to direct said rear ends of said foot links in an arcuate path of travel; a pair of internal guide track systems coupled to the frame, each internal guide track system being operative to engage the front end of each foot link and to direct said front end along a reciprocating path of travel while providing retention to each foot link; and a power transfer linkage in mechanical communication with said coupler assembly and with said drive wheel; whereby when the rear end of one of said foot links travels in said arcuate path and the front end of that foot link travels in said reciprocal path, an operator's foot supported thereupon travels in a generally elliptical path of travel, and said power transfer linkage transfers power from said coupler assembly to said drive wheel, so as to supply propulsive power thereto.
One or more implementations of the aspects of the invention described above include one or more of the following: the internal guide track system contains at least one structure configured to influence the reciprocating path of each foot link; the structure is removable from said internal guide track system; the internal guide track system includes one or more lower guide tracks; the one or more lower guide tracks are removable with respect to the internal guide track system; the front end of each foot link includes one or more load wheels, and the one or more lower guide tracks support the one or more load wheels for reciprocating path movement thereon and laterally influence the reciprocating path of the one or more load wheels; the one or more lower guide tracks are slidably removable with respect to the internal guide track system; the internal guide track system includes one or more upper guide features; the one or more respective upper guide features are removable with respect to the internal guide track system; the front end of each foot link includes one or more load wheels, and the one or more upper guide features are positioned to vertically influence the reciprocating path of the one or more load wheels there under; the one or more upper guide features are slidably removable with respect to the internal guide track system; the internal guide track system includes a longitudinal length and a bottom center, and a debris collecting gutter that extends along the longitudinal length, along the bottom center; the front end of each foot link includes one or more load wheels and the internal guide track system substantially encloses, contains, and protects the one or more load wheels from the environment; the front end of each foot link includes a top, a bottom, and sides, and the internal guide track system retains the top, bottom, and sides of the front end of each foot link; the internal guide track system vertically retains the top and the bottom of the front end of each foot link; and/or the internal guide track system laterally retains the sides of the front end of each foot link.
Other features and advantages of the present invention will become more readily apparent to those of ordinary skill in the art after reviewing the following detailed description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The details of the present invention, both as to its structure and operation, may be gleaned in part by study of the accompanying drawings, in which like reference numerals refer to like parts, and in which:
FIG. 1 is a front-elevational view of an embodiment of an elliptical bicycle including an internal guide track system constructed in accordance with an embodiment of the invention;
FIG. 2 is an enlarged cross-sectional of the internal guide track system taken along II-II of FIG. 1 .
FIG. 3 is a front-elevational view of another embodiment of an elliptical bicycle including an internal guide track system constructed in accordance with an alternative embodiment of the invention;
FIG. 4 is an enlarged cross-sectional of the alternate embodiment of the internal guide track system taken along IV-IV of FIG. 3 .
DETAILED DESCRIPTION
With reference to FIGS. 1 and 2 , an embodiment of an internal guide track system 100 of an elliptical bicycle 110 is shown. Before describing the internal guide track system 100 , the elliptical bicycle 110 will first be described.
The elliptical bicycle 110 includes a foot link assembly 112 movably mounted on a frame, or frame structure 114 , on which a pair of wheels (front wheel 115 , rear wheel 117 ) are mounted. Generally, each foot link assembly 112 is movably mounted to the frame 114 at its forward end where it is slidably coupled to a foot link guide track 290 (of the internal guide track system 100 ) and at its rearward end where it is rotatably coupled to a crank assembly 215 .
In the present embodiment, each foot link assembly 112 includes a foot link 205 , each with a foot platform 210 , and a foot link coupler 211 that contacts the foot link guide track 290 . In this embodiment, the foot link coupler 211 is comprised of two load wheels; however, in other embodiments, the foot link coupler can be comprised of any number of slidable devices, including a single wheel, a linear bearing, three or more wheels, etc. The foot platforms 210 on which the operator stands are mounted on an upper surface of each foot link 205 near a forward end of each foot link 205 . In the embodiment depicted in FIG. 1 , the internal guide track system 100 includes two foot link guide tracks 290 running parallel to each other on either side of the longitudinal axis of the elliptical bicycle 110 and are connected to or integral with the frame 114 . The two load wheels that comprise each foot link coupler 211 are mounted to a fixed axle 320 coupled to each foot link 205 to allow nearly frictionless linear motion of the foot links 205 along the foot link guide tracks 290 .
At the rear of the elliptical bicycle 110 , adjacent the rear wheel 117 , are crank arms 235 , a drive sprocket 240 , a crank arm bearing 245 , a chain 130 , a rear wheel sprocket 135 , and a rear wheel hub 145 . The crank arms 235 are mated to the crank arm bearing 245 , which is coupled to the frame 114 of the elliptical bicycle 110 , to turn the drive sprocket 240 .
During pedaling, the operator (not shown) uses his mass in a generally downward and rearward motion as in walking or jogging to exert a force on the foot platforms 210 and thereby, the foot links 205 . This force causes the load wheels 212 to roll along the foot link guide track 290 towards the rear of the elliptical bicycle 110 and rotate the crank arms 235 about the crank arm bearing 245 , turning the drive sprocket 240 . As with conventional bicycles, rotating the drive sprocket 240 causes the rear wheel sprocket 135 to rotate because they are linked by the chain 130 . It will be appreciated that in other embodiments, the chain 130 may be replaced by a belt, rotating shaft or other drive means, or the chain 130 , drive sprocket 240 and rear wheel sprocket 135 may be eliminated altogether by coupling the crank arms 235 directly to the rear wheel hub 145 . In this embodiment, rotating the rear wheel sprocket 135 causes the rear wheel 117 to rotate because the rear wheel sprocket 135 is attached to the rear wheel hub 145 . Rotating the rear wheel 117 provides motive force that enables the elliptical bicycle 110 to move along a surface. The elliptical bicycle 110 can employ a “fixed” or “free” rear wheel, as is known in the art. The elliptical bicycle 110 can also employ a planetary gear hub or derailleur system having different gear ratios.
Pedaling the elliptical bicycle 110 as described above results in the operator's foot traveling in a shape that can be described as generally elliptical. Propulsion using an elliptical pedaling motion, as opposed to an up-and-down pedaling motion or a circular pedaling motion, has the advantage of substantially emulating a natural human running or walking motion. Further, an elliptical pedaling motion is a simpler and a more efficient means to rotate the rear wheel 117 than is, for example, a vertical pumping motion. Moreover, the major axis of the ellipse in an elliptical pedaling motion can be much longer than the stroke length of a circular or vertical pumping pedaling motion, allowing the operator to employ a larger number of muscle groups over a longer range of motion during the pedal stroke than he or she could employ in a circular or up and down pedaling motion.
The internal guide track system 100 will now be described in more detail. The internal guide track system 100 includes one or more lower guide tracks 360 and/or one or more upper guide features 390 contained inside of elongated hollow, generally tubular frame 300 which form the interface between the foot link coupler 211 and the frame 114 of the elliptical bicycle 110 . The internal guide track system 100 ensures that the foot link coupler 211 reciprocates efficiently along the lower guide tracks 360 while the foot links 205 stay coupled to the elliptical bicycle 110 as part of a drive system that allows for a long stride length (>20 inches).
The internal guide track system 100 can include an elongated hollow, generally tubular frame 300 with an elongated narrow slot 310 along a top of the frame 300 that the foot link 205 reciprocates within. The foot link 205 is connected to the load wheels 212 by an axle 320 . Snap rings 340 or other fasteners are used to secure the load wheels 212 to the axle 320 .
A bottom, interior portion of the frame 300 includes track-receiving recesses 350 that receive respective removable lower guide tracks 360 that the load wheels 212 roll upon. The removable lower guide tracks 360 can be comprised of one or more of the following materials: hard anodized aluminum, electro less nickel coated aluminum, hardened steel/stainless steel, plastic. The removable lower guide tracks 360 can include an elongated curb 362 along an outer edge of the removable lower guide track 360 to ensure the load wheels 212 at the end of the foot links 205 travel in a nearly straight line and are prevented from contacting the inner side walls 364 of the frame 300 . The frame 300 can include an elongated debris gutter 370 extending the length of the frame 300 along a bottom center of the frame 300 . Debris can collect in and drain from the internal guide track system 100 via the gutter 370 .
At a top of the frame 300 are elongated penannular, substantially tubular guide recesses 380 that respectively receive removable upper guide features 390 . The removable upper guide features 390 can include an elongated tubular member 400 and a downwardly extending gap limiter 410 . Because the elliptical bicycle 110 is ridden outdoors, occasionally there will be a force applied to the elliptical bicycle 110 such that the rider and foot links 205 are propelled upwards. In such circumstances, the foot link coupler 211 riding on the lower guide tracks 360 can contact the lower engagement surfaces of the downwardly extending gap limiters 410 of the upper guide features 390 . The vertical length of the downwardly extending gap limiter 410 determines the gap spacing or vertical distance H between a top of the load wheel 212 and a bottom of the downwardly extending gap limiter 410 for limiting the amount of vertical “jump” of the load wheels 212 within the internal guide track system 100 . The removable nature of the removable upper guide features 390 enables upper guide features 390 of different dimensions (e.g., different sized/configured downwardly extending gap limiter 410 ) to be used, thereby modifying the gap H between the load wheels 212 and the upper guide features 390 .
The vertical thickness of downwardly extending gap limiter 410 is sized to achieve a proper gap spacing between a bottom thereof and the load wheels 212 as well as to minimize the friction between the load wheels 212 and the downwardly extending gap limiter 410 that results when the load wheels 212 come in contact with the downwardly extending gap limiter 410 . If the gap spacing H is too much, the load wheels can “jump” the guidance features (e.g., curbs 362 ) in the lower guide tracks 360 and get stuck at an angle or rub against the sides of the guide track tube frames 300 . If the gap spacing H is too tight, there will be too much contact between the tops of the load wheels 212 and the downwardly extending gap limiter 410 . Getting this gap spacing H correct is complicated by the fact that the load wheels 212 wear down over the lifetime of the elliptical bicycle 110 and, thus, the gap H between the load wheels 212 and the downwardly extending gap limiter 410 will continue to increase over time.
In alternative embodiment(s), the frame 300 of the internal guide tracks 290 includes other numbers (e.g., 1, 3, 4, 5. etc) of lower guide tracks 360 and/or upper guide features 390 , does not include upper guide features 390 , and/or does not include lower guide tracks 360 . For example, but not by way of limitation, guidance and retention methods can be accomplished via the structure of the generally tubular frame 300 without the addition of upper guide features 390 and lower guide tracks 360 . In this embodiment, the load wheels 212 would directly contact guide tracks that are integral with and a part of the frame 300 . For example, but not by way of limitation, the load wheels 212 may ride within guide tracks similar to the track recesses 350 . In such an embodiment, features such as elongated curbs 362 may be part of the track recesses 350 and frame 300 . In this embodiment, the majority of wear would take place on the track recesses of the frame 300 so the load wheels 212 may be made of a softer material to reduce wear on the frame 300 .
An alternative embodiment is depicted in FIGS. 3 and 4 , whereby the internal guide track system includes removal lower guide tracks and fixed upper guide features. In this embodiment, the gap spacing between the load wheels and the upper guide features is set at the distance between the lower guide tracks and the bottom of the fixed upper guide features. The lower guide tracks are removable and easily replaceable when worn, however, the upper guide features are an element of the frame of the internal guide track system and cannot be easily replaced.
Some advantages of the internal guide track system 100 are: 1) it provides a guidance system for the foot link coupler 211 that enables an inexpensive, low friction, and simple interface to function effectively; 2) it provides an elegant method of ensuring that the foot links 205 remain coupled to the frame 300 during operation; 3) it can include removable upper guide features and 390 /or lower guide tracks 360 made of a hard material or aluminum coated with a hard finish to improve resistance to wear, without changing the material properties of the frame 300 ; and 4) it can be modular and, therefore, worn elements can be easily replaced. Each of these aspects/advantages is described in turn below.
1) Guidance system: The upper guide features and lower guide tracks 360 , 390 are designed so that they have features (e.g., outer elongated curbs 362 , downwardly extending gap limiter 410 ) that ensure the foot link coupler 211 at the end of the foot links 205 travels in a nearly straight line and does not contact the walls 364 of the frame 300 .
2) Retention method: Because the foot links 205 interface with lower guide tracks 360 and upper guide features, 390 inside of structural members (i.e., frame 300 ), the foot links 205 are retained onto the frame 300 (and therefore prevented from disengaging with the frame 300 ) by the engagement between the frame member itself and the foot link coupler 211 (usually one or more load wheels 212 , but also could be a linear bearing, etc.). As a result, the internal guide track system 100 does not require an additional retention mechanism (unlike external track systems).
3) Hard anodization: Since they are a wear surface, the upper guide features 390 and lower guide tracks 360 can be made of or include a hard material or aluminum coated with a hard finish to increase their life and minimize the aluminization of the load wheels 212 that can occur during operation over machined aluminum that has not been anodized.
4) Modularity: The upper guide features 390 and lower guide tracks 360 can be easily removed from the elliptical bicycle 110 and replaced with new guide tracks and/or guide features. Over time, friction caused by the interface of the load wheels 212 and the upper guide features 390 and/or lower guide tracks 360 will cause both the load wheels 212 and the guide tracks/guide features 360 , 390 to become worn. The modular system allows for the easy replacement of the upper guide features 390 and lower guide tracks 360 when they become worn or damaged. For example, in an embodiment of the internal guide track system 100 , the internal guide track system 100 may include end(s) accessible by a door/cap/cover for removably replacing the upper guide features 390 and lower guide tracks 360 . The modularity also enables the use of a hard or specialty hard coated material to be limited to the engaged surface of the upper guide features 390 and/or lower guide tracks 360 only. If the upper guide features 390 and/or lower guide tracks 360 were not removable, then a larger structure would have to be made of a hard or specialty hard coated material, adding cost and weight.
In an alternative embodiment, the modularity enables the upper guide features 390 and/or lower guide tracks 360 to be made of a softer material such as a plastic. These softer guide tracks/features 360 , 390 would insure that the majority of the wear would take place on the track side of the rolling interface and preserve the life of the load wheels 212 if they were made from a harder material. The plastic guide tracks/features 360 , 390 would protect the structural frame from wear and could be cheaply and easily replaced throughout the life of the product.
Additionally, or alternatively, the entire internal guide track system 100 may be easily extracted from the frame 114 of the elliptical bicycle 110 and easily replaced with a new internal guide track system 100 . Thus, one or more of the entire internal guide track system 100 and components (e.g., guide tracks/features 360 , 390 ) allow for modularity and interchangeability.
Thus, the internal guide track system 100 eliminates the need for an additional coupling mechanism to keep the foot links 205 coupled to the frame 300 ; allows for a sufficiently long stride length; maximizes the likelihood that the foot links 205 will remain coupled to the frame and not disengage during operation; hard anodization reduces the rate of wear on the upper guide features 390 and/or lower guide tracks 360 and “aluminization” of the load wheels 212 during operation; and modularity enables the easy replacement of one or more of the entire internal guide track system 100 and worn upper guide features 390 and/or lower guide tracks 360 and allows for the use of a hard or specially hard coated material to be limited to the engagement surface of the upper guide features 390 and/or lower guide tracks 360 exclusively, which are small surfaces, thereby minimizing cost and weight. Use of a softer material such as plastic would insure that the majority of the wear would take place on the track side of the rolling interface and would preserve the life of the load wheels 212 if made from a harder material. The plastic upper guide features 390 and/or lower guide tracks 360 protect the structural frame 300 from wear and are cheaply and easily replaced throughout the life of the product.
The above figures may depict exemplary configurations for the invention, which is done to aid in understanding the features and functionality that can be included in the invention. The invention is not restricted to the illustrated architectures or configurations, but can be implemented using a variety of alternative architectures and configurations. Additionally, although the invention is described above in terms of various exemplary embodiments and implementations, it should be understood that the various features and functionality described in one or more of the individual embodiments can be applied, alone or in some combination, to one or more of the other embodiments of the invention, whether or not such embodiments are described and whether or not such features are presented as being a part of a described embodiment. Thus the breadth and scope of the present invention, especially in any following claims, should not be limited by any of the above-described exemplary embodiments.
Terms and phrases used in this document, and variations thereof, unless otherwise expressly stated, should be construed as open ended as opposed to limiting. As examples of the foregoing: the term “including” should be read as mean “including, without limitation” or the like; the term “example” is used to provide exemplary instances of the item in discussion, not an exhaustive or limiting list thereof; and adjectives such as “conventional,” “traditional,” “standard,” “known” and terms of similar meaning should not be construed as limiting the item described to a given time period or to an item available as of a given time, but instead should be read to encompass conventional, traditional, normal, or standard technologies that may be available or known now or at any time in the future. Likewise, a group of items linked with the conjunction “and” should not be read as requiring that each and every one of those items be present in the grouping, but rather should be read as “and/or” unless expressly stated otherwise. Similarly, a group of items linked with the conjunction “or” should not be read as requiring mutual exclusivity among that group, but rather should also be read as “and/or” unless expressly stated otherwise. Furthermore, although item, elements or components of the disclosure may be described or claimed in the singular, the plural is contemplated to be within the scope thereof unless limitation to the singular is explicitly stated. The presence of broadening words and phrases such as “one or more,” “at least,” “but not limited to” or other like phrases in some instances shall not be read to mean that the narrower case is intended or required in instances where such broadening phrases may be absent. | An apparatus includes a frame with a pivot axis defined thereupon; a drive wheel coupled to the frame; a first and a second foot link operably coupled to the drive wheel to transfer power to the drive wheel so as to propel the apparatus, each including a foot receiving portion for receiving an operator's foot, a front end, and a rear end; and a pair of internal guide track systems coupled to the frame, each internal guide track system being operative to engage the front end of each foot link internal to the internal guide track system and to direct the front end along a reciprocating path of travel while providing retention to each foot link. | 1 |
U.S. GOVERNMENT INTERESTS
[0001] This invention was made with U.S. government support under a co-operative agreement awarded by the U.S. Army. The U.S. government may have certain rights to the invention.
BACKGROUND OF THE INVENTION
[0002] Electrostatic fiber formation, or “electrospinning” is a process that employs electrostatic forces to produce fibers with diameters ranging from microns down to tens of nanometers—two to three orders of magnitude smaller than those produced by conventional fiber spinning methods. While electrospinning of fibers first occurred in the 1930's (U.S. Pat. No. 2,077,373) (1934), the process has only recently attracted greater attention due to its simplicity in making nanofibers from both synthetic and natural polymers.
[0003] Electrospinning itself is quite general. Despite the fact that over 30 different polymers have been electrospun in batch or continuous mode to produce fibers with diameters below 1 micron, there are still many fluids that cannot be electrospun or are very difficult to electrospin. The present invention expands the use of electrospinning to these fluids. Numerous, diverse applications for electrospun fibers have been proposed. These include: bio-degradable electrospun non-woven fabrics for use in tissue engineering and in drug delivery; high surface area fabrics for use in protective clothing and sensors; and highly efficient filtration membranes based on small inter-fiber distances combined with low pressure drop. Also electrospun fibers have been post-treated to produce ceramic and metallic nanofibers. Despite the encouraging results of electrospun fibers, routine production of uniform fibers with diameters less than 500 nm, preferably less than 100 nm, along the entire length of the fiber is still a challenge, particularly from those fluids that are not readily electrospinnable.
[0004] Electrospinning itself has been problematic because some of the spinnable fluids are very viscous and require higher forces than electric fields can supply before sparking occurs, i.e., there is a dielectric breakdown in the air. Other fluids, particularly those which have been diluted in an attempt to produce fibers having diameters in the namometer range, are often found to be so dilute that jets break up into a spray of drops, precluding continuous fiber formation. Likewise, the techniques have been problematic when higher temperatures are required because the higher temperatures increase the conductivity of structural parts and complicate the control of high electrical fields.
[0005] Heretofore, two major strategies to decrease fiber diameter have generally been employed. The first has entailed reducing the concentration of polymer in the spin solution, thereby relying on solvent removal to produce a residual solid fiber of a smaller diameter. This approach suffers from low productivity (the majority of the spun fluid is a sacrificial solvent) and high solvent handling issues as well as droplet formation. The second approach has been to increase the charge-carrying capacity of the fluid through addition of suitable, usually non-polymeric, additives. The additive approach has led to suppression of the Rayleigh instability and enhancement of the whipping instability, thereby leading to dramatic stretching and thinning of the fluid jet. The production of smaller fibers can be understood in terms of a limiting jet diameter which results from this stretching process has been confirmed experimentally using polycaprolactone solutions with varying levels of induced charge. For example, when palladium(II) diacetate was added to a solution of poly(L-lactide) in dichloromethane to increase its conductivity and charge density, the fiber diameter was reduced to 5 nanometers.
[0006] In numerous cases, however, polymers that are of the most current interest as materials to form nanofibers cannot be electrospun to form fibers at all. Such fibers are referred to hereafter as “non-electrospinnable” while those fluids that readily form uniform, continuous fibers are “electrospinnable.” Common problems limiting electrospinnability of a polymer include poor solubility, limitations on available molecular weights, and unusually rigid or compact (“globular”) molecular conformations. These limitations are sometimes interpreted using a metric based on the Berry Number, which is defined as the product of intrinsic viscosity [η] and concentration. The Berry Number provides a qualitative indication of cross-over into a semi-dilute solution regime, where entanglements between chains may become effective. More precisely, some degree of elasticity is required, in the absence of which electrospun fluids generally do not form uniform fibers. Instead, droplets or “beads-on-strings” are formed.
[0007] Although there are previous reports of pure silk fibers electrospun from solutions, they have been in non-aqueous solvents like hexafluoro-2-isopropanol and formic acid (see Zarkoob et al, Pollymer 2004, 45, 3973; Sukigara et al, Polymer 2003, 44, 5721), where solubility is not a problem. Water is a more benign solvent, but silk is not as soluble in water so that the concentration cannot be made high enough to form a spinnable solution of silk in water. One attempt to overcome the “spinnability” problem with aqueous solutions of silk has been to add a miscible high molecular weight polyethylene oxide (PEO) polymer to the solution. The added component, being itself electro-spinnable, rendered the silk/PEO mixture electrospinnable. However, the resultant fiber is a silk-PEO blend, not pure silk. The 2-fluid process of this invention allows the formation of pure silk fibers for the first time from an aqueous solution.
[0008] A similar strategy to provide electrospinnability to a polymer has entailed adding PEO to polyaniline (Pani) and electrospinning the mixture into fibers. The result has been fiber blends wherein the fibers have had compromised properties, such as mechanical integrity, conductivity, and biocompatibility. Attempts to remove the PEO portion of the fiber blends by post-processing (extraction) have not been successful, resulting in undesirable fiber properties after extraction.
[0009] U.S. Pat. Nos. 6,382,526, 6,520,425 and 6,695,992 disclose process and apparatus for forming a non-woven mat of nanofibers by using a pressurized gas stream. The process entails feeding a fiber-forming material into an annular column, the column having an exit orifice, directing the fiber-forming material into a gas jet space, thereby forming an annular film of fiber-forming material, the annular film having an inner circumference, simultaneously forcing gas through a gas column concentrically positioned within the annular column, and into the gas jet space, thereby causing the gas to contact the inner circumference of the annular film. The resulting fiber-forming material ejects from the exit orifice of the annular column in the form of a plurality of strands of fiber-forming material that solidify and form nanofibers having large diameters, often as much as about 3,000 nanometers.
[0010] The present invention overcomes the aforementioned problems.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a schematic drawing of a two-fluid electrospinneret in accordance with the present invention.
[0012] FIG. 2A is an external view of the two-fluid electrospinneret used in the Examples below. FIG. 2B is an external view of the two fluid electrospinneret of FIG. 2A prior to complete assembly.
[0013] FIG. 3A is an SEM image of the core-shell fiber of Example 1; FIG. 3B is an axial TEM view of the fiber of Example 1; FIG. 3C is a lateral TEM view of the fiber of Example 1.
[0014] FIG. 4A is an SEM image of the 8 wt % polyacrylonitrile (PAN) core fiber of Example 1 prior to removal of its polyacrylonitrile-co-polystyrene (PAN-co-PS) shell; FIGS. 4B , C, and D are SEM images of fibers prepared from 5, and 3 wt % PAN, respectively, prepared in accordance with this invention, shown after removal of the PAN-co-PS shell.
[0015] FIGS. 5A , B, and C are SEM images of polyacrylonitrile polymer fibers containing respectively 8, 5, and 3 wt % polyacrylonitrile, but prepared in accordance with Comparative Example A by a single fluid electrospinning procedure, i.e. in the absence on a shell fluid.
[0016] FIG. 6A is an SEM image of silk core/polyethylene oxide (PEO) shell fibers; FIG. 6B is the fiber mat of FIG. 6A after being soaked in methanol before removing the PEO in water; and FIG. 6C is a TEM image showing that the core/shell fiber of FIG. 6A has a thin PEO shell.
SUMMARY OF THE INVENTION
[0017] The present invention is directed to substantially continuous fibers which as prepared have a core-and-shell structure. The fibers may be further process to remove either the shell or the core. The core fibers have a uniform diameter of less than about 1 micron, preferably generally less than about 500 nm, and most preferably less than about 100 nm. The invention is further directed to a process to for manufacture of the fibers. The fluid used to form the shell is an electrospinnable fluid. The fluid used to form the core fiber can be electrospinnable, but preferably it is either not electrospinnable at all or is very hard to process using conventional single fluid spinning methods.
[0018] The fibers are formed by use of a two-fluid electrospinneret to make fibers with a shell-and-core structure. The shell fluid can serve as a process aid for the core fluid. The core of the fibers can optionally be exposed by removal of the shell material in a post-treatment. The shell of the fibers can optionally be formed into hollow fibers by removal of the core material in a post-treatment. The final morphology of the fibers can be modified by controlling processing parameters (rates, voltage, current, etc.) and fluid properties (conductivity, viscosity, etc.). Complex electro-hydrodynamics are involved in the two-fluid electrospinning.
[0019] The fibers produced by the two-fluid electrospinning process have a broad range of applications. Use of the shell-core system extends the range of concentrations and molecular weights of polymers that can be electrospun into fibers. Thus finer fibers are possible than heretofore and new materials can now be processed.
[0020] Either the core or shell fluids can be doped with additives. For example, the core fluid can carry a drug while the shell served as a thin barrier for controlled, long-term release. Alternatively, the shell fluid can carry surface active agents such as biocides, chemical agent neutralizers, or coagulants, while the core provides structural support and longevity.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] This invention is directed to the preparation of electrospun fibers from difficult-to-process fluids and of fibers with smaller diameters and core-shell structure. The process utilizes an electrospinneret as shown in FIGS. 1 and 2 that allows for co-axial extrusion of two fluids. The housing of the electrospinneret 10 consists of a concentric inner tube 12 and outer tube 14 by which two fluids are introduced to the spinneret, one (hereafter denoted the “core fluid”) in the core of the inner tube 12 and the other (hereafter denoted the “shell fluid”) in the annular space between the inner tube 12 and the outer tube 14 . The electro-spinneret is designed to keep the fluids separate as they are charged via a high energy source 16 and emitted from a nozzle 20 .
[0022] The materials of construction are chosen such that either one or both of the fluids may be charged by contact with a high voltage as the fluid passes through the spinneret. In the examples below the spinneret shown in FIG. 2 was used in a parallel plate equipment configuration. The spinneret has two generally steel tubes so that both fluids were charged simultaneously to the same potential. In the specific device shown, the inner tube 12 having an i.d. of 0.46 mm and an o.d. of 0.79 mm if fed through feedline 13 , while the outer tube 14 has an i.d. of 2.03 mm and an o.d. of 3.18 mm and is fed through feedline 15 . The core feedline 13 leads to a PEEK ferrule 22 which is attached to a PEEK O-ring 24 which connects into PEEK connector 26 . The opposite end of PEEK connector 26 connects to a PEEK ferrule and steel cap 30 by an adhesive O-ring 28 . The core side steel cap connects to one leg of a steel T-tubing connector 32 in the in-line direction with core tube 12 extending through the center thereof. The side leg of the T-tubing connector 32 connects to shell feedline 15 by means of ferrule 34 and steel cap 30 . The core tube 12 and shell tube 14 jointly exit the T-tubing connector 32 as a concentric tube assembly through a further steel cap 30 and ferrule 34 . The concentric tube assembly protrudes from the center of a top disk (not shown in FIG. 2 ) by an adjustable amount. A second disk (as seen in FIG. 1 ) was used as a collector by connecting it to the ground. The disks were made of aluminum and were 12 cm in diameter, separated by a distance up to 45 cm, though other materials, sizes and distances may be used.
[0023] Other equipment configurations, such as those involving a moving collector wheel or belt, may also be used.
[0024] To be able to function as a processing aid for the core material, the shell fluid must be an electrospinnable fluid. The core fluid, on the other hand, does not need to be an electrospinnable fluid. Preferably, in fact, the core fluid does not, on its own, readily form a fiber by electrospinning. During electrospinning, the shell fluid forms a sheath around the core fluid, which stabilizes it against break-up into droplets by a process such as Rayleigh instability.
[0025] Stabilization based on the introduction of a shell fluid is believed to operate through two mechanisms. (1) By replacing the normal exterior fluid (typically air or vacuum in conventional single-fluid electrospinning) with a viscoelastic medium, the Rayleigh instability in the core fluid can be delayed or suppressed completely; when the exterior fluid is furthermore spun as a shell fluid, as described here, stretching of the shell component imparts greater elasticity to the interface, i.e. strain hardening, further stabilizing the core fluid. (2) The shell fluid also reduces the very surface forces at the boundary of the core fluid which drive the break-up of the core fluid into droplets by replacing the relatively high fluid-vapor surface tension typically present in single-fluid electrospin-ning by a lower fluid-fluid interfacial tension.
[0026] During the electrospinning, the fluids can travel at speeds of tens of meters per second upon exiting the nozzle. The two fluids may or may not be miscible. However, the short time duration of the process prevents the two fluids from mixing significantly. The use of a common solvent for the two fluids favors a particularly low interfacial tension. In the case of polymer solutions, the polymers must not precipitate at the fluid interface near the nozzle.
[0027] Generally suitable and currently preferred operating conditions are given in Table I. Specific operating conditions for particular compositions can be readily determined via trial and error.
TABLE I OPERATING PARAMETER GENERAL PREFERRED Voltage range, kV 1 to 100 5 to 30 Distance to collector, cm 10 to 100 20 to 40 Core fluid flow rate, ml/min 0.001 to 0.01 0.001 to 0.005 Shell fluid flow rate, ml/min 0.01 to 1 0.02 to 0.1 Fluid viscosity, Pa · s 0.01 to 100 0.1 to 10 Fluid conductivity, μS/cm at least 0.01 0.5 to 100 Concentrations by mass, wt % at least 0.1 3 to 30 Fluid surface tension, N/m 0.01 to 0.2 0.023 to 0.08 Continuous fiber diameter 1 nm to 1 micron 50 to 400 nm
[0028] One important core polymer fiber that can be prepared in accordance with the present invention is silk. Previous silk fibers have been blends of silk and a hydrophillic polymer such as polyethylene oxide while the present silk polymer fibers do not contain any additive to make the silk spinnable. Rather silk is used in the core of a core-and-shell fiber within a shell of an electrospinnable composition. Suitable operating parameters for producing the silk fibers are quite similar to the parameters given in Table I. The core fluid and shell fluid flow rates are comparable for both systems. Somewhat lower field strengths are recommended for the silk systems—about 0.4 kV/cm as compared to about 1 kV/cm—because of differences in characteristics, e.g. concentration and molecular weights, of the polymers and solvents used. The fluids (silk or otherwise) need to have solution properties (viscosity, conductivity, and surface tension) within the general ranges specified above. All fluids are solutions of polymer in solvent. If the molecular weight of polymer is low, then the concentration needs to be increased to get the desired fluid properties.
[0029] The two-fluid electrospinning process of the present invention may be used to form core fibers from any polymer solution having the fluid properties specified herein. While the process can produce fibers from essentially any polymer, it is most noteworthy for being able to form fibers from polymers that are not readily spinnable on their own. Suitable polymers generally are those having a low molecular weight or form dilute solutions because either of these characteristics can render a polymer unspinnable.
[0030] Silk is one of the polymers that is of particular importance. It is poorly soluble in water even with added salts. Silk has application in mechanical reinforcement (e.g. composites, cables); other polymers that compete with it in that application include Kevlar, Nomex (both aramids) and polyurethanes (e.g. Elastane). The aramids are also only sparingly soluble. Other polymers that are useful as biomaterials are natural polymers (collagen, fibrin, elastin, most of which are only sparingly soluble) and degradable polymers like polyhydroxyalkanoates (e.g. polycaprolactone, polylactic acid, polyglycolic acid, and copolymers of these). Polyanilinesulfonic acid is useful to make conductive fibers (“wires”), and is another example of a difficult to dissolve material that is hard to spin on its own.
[0031] In the non-limiting Examples below, all parts and percents are by weight unless otherwise specified.
[0032] To demonstrate the usefulness of this invention for making fibers, three prototypical core/shell systems were used: PAN/PAN-co-PS (Examples 1-2), Pani/PVA (Example 3), and silk/PEO (Example 4). Specific processing conditions are detailed in the Examples. Each of the solutions was delivered to a two-fluid electrospinneret as a core or shell fluid at appropriate flow rates to keep the core-shell jet continuous. The voltage applied to the spinneret was sufficiently low that the electrical force did not pull the fluids too fast or too slow at the nozzle. If the core fluid flow rate is set too high, the core fluid jet breaks into droplets. If the shell fluid flow rate is set too high, shell fibers form without a continuous thread of the core material. During steady operation, concentric Taylor cones formed by the two fluids are observable.
[0033] The present invention is based in part upon the discovery that proper choice of a miscible fluid, even when using a common solvent, can serve to reduce the interfacial tension on the core stream, allowing production of smaller diameter fluids and even fibers from non-electrospinnable fluids.
[0034] The resulting fibers were examined by taking fiber images using electron microscopes. The fibers were coated with a 10 nm layer of gold for SEM imaging. A SEM (JOEL SEM 6320) instrument was used to observe the general features of the fibers. A TEM (JOEL 200CX) instrument was used to observe the core-shell structure of the fibers. For the TEM lateral view, fibers were deposited directly onto a copper TEM grid. For the TEM axial view of PAN/PAN-co-PS fibers, they were first fixed in epoxy and then ultramicrotomed to cut 100 nm slices. Chloroform was used to remove the PAN-co-PS shell from PAN/PAN-co-PS fibers.
EXAMPLE 1
[0035] A two-fluid electrospinneret as shown in FIG. 2 was used to prepare a nanofiber having a core of polyacrylonitrile (PAN), which is of particular interest as a precursor to carbon nanofibers. PAN (MW 150,000) was dissolved in N,N-dimethylformamide (DMF) to form an 8 wt % solution. The fluid used for the outer shell layer was 20 wt % polyacrylonitrile-co-polystyrene (PAN-co-PS) (MW 165,000) dissolved in N,N-dimethylformamide.
[0036] The two fluids were processed through the electrospinneret at a voltage of 26 kV and using a disk separation of 40 cm. The PAN had a flow rate of 0.008 ml/min. The PAN-co-PS had a flow rate of 0.07 ml/min.
[0037] FIG. 3A is an SEM image of the resultant core-shell fiber produced. FIGS. 3B and 3C are axial and lateral TEM views of the fiber.
[0038] Although the formation of PAN fibers with diameters of 50 nm have been reported in the literature, the overall size distribution in that case was bimodal, with average diameters around 100 nm and 200 nm. The fiber size distribution can be made more narrow, and the fibers more uniform, by increasing the PAN concentration, but it causes the fiber size to increase. In less concentrated PAN solutions the Rayleigh instability dominates and prevents formation of fibers.
EXAMPLE 2
[0039] The procedure of Example 1 was repeated to produce additional PAN fibers at varying polymer concentrations. The concentrations and electrospinning conditions used were:
Systems 1 2 3 Voltage 26 kV 28 kV 30 kV Disk 40 cm 40 cm 35 cm Separation Core-fluid 8% wt 5% wt 3% wt Polyacrylonitrile Polyacrylonitrile Polyacrylonitrile (PAN) (PAN) (PAN) Mw 150,000 Mw 150,000 Mw 150,000 in N,N-dimethyl- in N,N-dimethyl- in N,N-dimethyl- formamide formamide formamide (DMF) (DMF) (DMF) Flow rate 0.008 ml/min 0.008 ml/min 0.002 ml/min Shell-fluid 20% wt 25% wt 28% wt Polyacrylonitrile- Polyacrylonitrile- Polyacrylonitrile- co-Polystyrene co-Polystyrene co-Polystyrene (PAN-co-PS) (PAN-co-PS) (PAN-co-PS) 25% wt 25% wt 25% wt acrylonitrile acrylonitrile acrylonitrile Mw 165,000 Mw 165,000 Mw 165,000 in DMF in DMF in DMF Flow rate 0.07 ml/min 0.07 ml/min 0.04 ml/min
[0040] FIG. 5A is the SEM image of an 8 wt % polyacrylonitrile (PAN) core fiber before removal of its polyacrylonitrile-co-polystyrene (PAN-co-PS) shell. The average fiber diameter was about 500 nm.
[0041] FIGS. 5B , C, and D are SEM's of the 3 fibers after the removal of the shell material (PAN-co-PS) by dissolving in chloroform. As can be seen, the residual PAN fibers prepared by the 2-fluid process were all found to be quite uniform.
[0042] Uniform fibers were obtainable from the 5 and 3 wt % concentrations by two-fluid electrospinning, with the presence of the shell polymer in fluid, as shown in Example 2 above. The increase in the mass concentration of the shell fluid was useful to suppress further the Rayleigh instability in the 3 wt % PAN core fluid. Fibers recovered after the removal of the shell had average diameters of 105 nm (s.d. 25) and 65 nm (s.d. 15) from the 5 wt % and 3 wt % PAN solutions, respectively, and were unimodal in distribution ( FIGS. 5C and 5D ).
COMPARATIVE EXAMPLE A
[0043] The three polyacrylonitrile (PAN) solutions of Example 2 were sub-jected to electrospinning conditions using the spinneret of FIG. 2 , but in the absence of a shell fluid.
[0044] The resulting products were examined by SEM and the results are shown in FIGS. 4A , B, and C, respectively for the 8, 5, and 3 wt % PAN products.
[0045] The 5 wt % PAN solution in DMF, when electrospun in single-fluid mode, formed heavily beaded non-uniform fibers. The 3 wt % PAN solution could not be electrospun into fibers at all, due to break-up of the jet into droplets.
EXAMPLE 3
[0046] Nanofiber polyaniline (PAni) is of an interest for the formation of conducting nanowires, but is difficult to process in part due to low molecular weight and limited solubility in electrospinnable solutions.
[0047] Thus the procedure of Example 1 was repeated with a PAni/PVA—polyanilinesulfonic acid/polyvinyl alcohol—core/shell system. The electrospinning conditions and the fluids used were:
System 4 Voltage 20 kV Disk 25 cm Separation Core-fluid 5% wt Poly(anilinesulfonic acid) (PAni) in water Flow rate 0.005 ml/min Shell-fluid 8% wt Poly(vinyl alcohol) (PVA) Mw 146,000-86,000; in water Flow rate 0.01 ml/min
[0048] Examination of the resulting fibers showed that the PAni/PVA fibers had an average diameter of 310 nm. A lateral TEM image showed that the PAni core had a diameter of 120 nm. About a third of the fibers did not exhibit the core/shell structure. PAni is significantly more conductive than PVA, and it is believed that it has a higher volume charge density than PVA solution and thus was pulled by the electric field at a higher rate than the feed line could supply, resulting in a discontinuous stream of PAni solution. When a sufficient amount of PAni solution accumulated at the nozzle, the core/shell structure formed again.
EXAMPLE 4
[0049] Natural silk is a good material for tough biocompatible fibers, but an aquesous solution of it cannot be electrospun because silk is not sufficiently soluble in water to make a solution having an appropriate balance of concentration and viscosity. Moreover, when additives are used to enhance solubility, the resulting aqueous solutions have a tendency to gel at high concentrations.
[0050] The procedure of Example 1 was repeated with a Silk/PEO—Bombyx mori silk/polyethylene oxide—core/shell system to produce a pure silk polymer fiber, i.e. not a mixture of silk and a second polymer such as PEO. The electrospinning conditions and the specific fluids used were:
System 5 Voltage 9 kV Disk 37 cm Separation Core-fluid 8 wt % Bombyx mori silk in water Flow rate 0.0075 ml/min Shell-fluid 8 wt % Poly(ethylene oxide) (PEO) Mw 1,500,000; in water Flow rate 0.01 ml/min
[0051] The resultant continuous silk/PEO core/shell fibers had an average diameter of 800 nm and when viewed by SEM were uniform. The average diameter decreased to about 600 nm after removal of the PEO shell and the pure silk core fibers appeared slightly non-uniform in diameter. The lateral TEM image confirmed that the PEO shell was thinner than the silk core. The non-uniformity of these pure silk core fibers was probably due to the high gelation rate of the silk solution causing some non-uniformity in its elastic properties. The aqueous silk solution was very unstable; small disturbances or additions of foreign particles set off immediate gelation. While the shell-fluid was still stretching in flight, gelation prevented the core from further stretching.
[0052] The relatively large 600 nm diameter silk fiber diameter is because the purpose of the experiment was to demonstrate the feasibility of preparing a “pure” silk fiber. Fine tuning of the system will produce fibers with smaller diameters. Suitable operating conditions which can be used to produce pure silk fibers are shown in Table II.
TABLE II OPERATING PARAMETER GENERAL PREFERRED Electrical field, kV/cm 0.2 to 0.45 0.3-0.4 Silk (core) fluid flow rate, ml/min 0.001 to 0.008 0.002 to 0.004 PEO (shell) fluid flow rate, ml/min 0.01 to 0.08 0.02 to 0.05 Concentration silk in fluid, wt % 4 to 10 7 to 9 Concentration PEO in fluid, wt % 1 to 3 1.5 to 2.5 PEO avg. molecular weight 1M to 3M about 1.5M Fluid surface tension, N/m 0.01 to 0.2 0.023 to 0.08 Continuous fiber diameter, nm 50 to 1000 100 to 800 | Electrospinning of materials that are difficult or impossible to process into nanofibers by conventional fiber-forming techniques or by electrospinning are prepared by an electrospinning procedure which uses an electrospinnable outer “shell” fluid around an inner “core” fluid, which may or may not be electrospinnable, to form nanofibers of the inner core fluid having a core/shell morphology. The resulting shell around the nanofiber can remain in place or be removed during post-processing with the core of the fiber remaining intact. The dual-fluid electrospinning process can produce core fibers having diameters less than 100 nm, insulated nanowires, as well as tough, bio-compatible silk fibers. Alternatively, the core can be removed leaving a hollow fiber of the shell fluid. | 3 |
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a divisional from U.S. patent application Ser. No. 09/074,496, filed on May 7, 1998 by James R. Albritton and entitled “Breakaway Support Post for Highway Guardrail End Treatments” that claims benefit of U.S. Provisional Application Serial No. 60/046,015 filed May 9, 1997.
The application is also related to U.S. Divisional patent application Ser. No. 09/835,282 filed Apr. 12, 2001 and entitled “Breakaway Support Post for Highway Guardrail End Treatments”, now U.S. Pat. No. 6/488,268.
TECHNICAL FIELD OF THE INVENTION
The present invention relates to highway guardrail systems having a guardrail mounted on posts, and more particularly, to guardrail end treatments designed to meet applicable federal and state safety standards including but not limited to crash worthiness requirements.
BACKGROUND OF THE INVENTION
Along most highways there are hazards which present substantial danger to drivers and passengers of vehicles if the vehicles leave the highway. To prevent accidents from a vehicle leaving a highway, guardrail systems are often provided along the side of the highway. Experience has shown that guardrails should be installed such that the end of a guardrail facing oncoming traffic does not present another hazard more dangerous than the original hazard requiring installation of the associated guardrail systems. Early guardrail systems often had no protection at the end facing oncoming traffic. Sometimes impacting vehicles became impaled on the end of the guardrail causing extensive damage to the vehicle and severe injury to the driver and/or passengers. In some reported cases, the guardrail penetrated directly into the passenger's compartment of the vehicle fatally injuring the driver and passengers.
Various highway guardrail systems and guardrail end treatments have been developed to minimize the consequences resulting from a head-on impact between a vehicle and the extreme end of the associated guardrail. One example of such end treatments includes tapering the ends of the associated guardrail into the ground to eliminate potential impact with the extreme end of the guardrail. Other types of end treatments include breakaway cable terminals (BCT), vehicle attenuating terminals (VAT), the SENTRE end treatment, and breakaway end terminals (BET).
It is desirable for an end terminal assembly installed at one end of a guardrail facing oncoming traffic to attenuate any head-on impact with the end of the guardrail and to provide an effective anchor to redirect a vehicle back onto the associated roadway after a rail face impact with the guardrail downstream from the end terminal assembly. Examples of such end treatments are shown in U.S. Pat. No. 4,928,928 entitled Guardrail Extruder Terminal, and U.S. Pat. No. 5,078,366 entitled Guardrail Extruder Terminal.
A SENTRE end treatment often includes a series of breakaway steel guardrail support posts and frangible plastic containers filled with sandbags. An impacting vehicle is decelerated as the guardrail support posts release or shear and the plastic containers and sandbags are compacted. A cable is often included to guide an impacting vehicle away from the associated guardrail.
A head-on collision with a guardrail support post located at the end of a guardrail system may result in vaulting the impacting vehicle. Therefore, guardrail end treatments often include one or more breakaway support posts which will yield or shear upon impact by a vehicle. Examples of previously available breakaway posts are shown in U.S. Pat. No. 4,784,515 entitled Collapsible Highway Barrier and U.S. Pat. No. 4,607,824 entitled Guardrail End Terminal. Posts such as shown in the '515 and the '824 patents include a slip base with a top plate and a bottom plate which are designed to not yield upon lateral impact. When sufficient axial impact force is applied to the upper portion of the associated post, the top plate and the bottom plate will slide relative to each other. If a vehicle contacts the upper part of the post, the associated impact forces tend to produce a bending moment which may reduce or eliminate any slipping of the top plate relative to the bottom plate. Also, improper installation of the top plate relative to the bottom plate, such as over tightening of the associated mechanical fasteners, may prevent proper functioning of the slip base. A breakaway support post is also shown in U.S. Pat. No. 5,503,495 entitled Thrie-Beam Terminal with Breakaway Post Cable Release.
Wooden breakaway support posts are frequently used to releasably anchor guardrail end treatments and portions of the associated guardrail. Such wooden breakaway support posts, when properly installed, generally perform satisfactorily to minimize damage to an impacting vehicle during either a rail face impact or a head-on impact. However, impact of a vehicle with a wooden breakaway support post may often result in substantial damage to the adjacent soil. Removing portions of a broken wooden post from the soil is often both time consuming and further damages the soil. Therefore, wooden breakaway support posts are often installed in hollow metal tubes, sometimes referred to as foundation sleeves, and/or concrete foundations. For some applications, one or more soil plates may be attached to each metal sleeve to further improve the breakaway characteristics of the associated wooden post. Such metal sleeves and/or concrete foundations are relatively expensive and time consuming to install.
Light poles, sign posts or similar items are often installed next to a roadway with a breakable or releasable connection. For some applications, a cement foundation may be provided adjacent to the roadway with three or more bolts projecting from the foundation around the circumference of the pole. Various types of frangible or breakable connections may be formed between the bolts and portions of the light pole or sign post.
SUMMARY OF THE INVENTION
In accordance with teachings of the present invention, various shortcomings of previous guardrail support posts associated with highway guardrail end treatments have been addressed. The present invention provides a breakaway support post which will buckle or yield during head-on impact by a vehicle at or near the extreme end of an associated guardrail to minimize damage to the vehicle and provide sufficient strength to direct a vehicle back onto an associated roadway during a rail face impact with the guardrail downstream from the guardrail end treatment. The use of breakaway support posts incorporating teachings of the present invention substantially reduces the time and cost associated with initial installation of a guardrail end treatment and repair of the guardrail end treatment following impact by a motor vehicle.
One aspect of the present invention includes providing a breakaway support post having one or more slots formed in the support post to allow the support post to buckle or yield in response to forces applied to the support post in a first direction by an impacting vehicle without causing excessive damage to the vehicle. The orientation and location of the slots are selected to allow the support post to effectively anchor the guardrail to direct an impacting vehicle back onto an adjacent roadway in response to forces applied to the support post in a second direction during a downstream rail face impact. For some applications, one or more plates may be attached to the breakaway support post and inserted into the soil to provide additional support during a rail face impact with the associated guardrail and to provide more reliable buckling or yielding of the breakaway support post during a head-on impact with one end of the associated guardrail. Alternatively, the length of the portion of the breakaway support post inserted into the soil may be increased to enhance these same characteristics. For some applications, the breakaway support post may have a typical I-beam cross section with slots formed in one or more flange portions of the I-beam. Alternatively, the breakaway support post may have a hollow, rectangular or square cross section with slots formed in one or more sides of the post in accordance with teachings of the present invention.
Another aspect of the present invention includes providing a breakaway support post having a first portion or an upper section and a second portion or a lower section with the first portion rotatably coupled with the second portion. A pivot pin or other suitable type of rotatable coupling preferably connects adjacent ends of the first portion and the second portion to allow rotation of the first portion relative to the second portion. The pivot pin is preferably oriented during installation of the associate breakaway support post to allow rotation of the first portion when force is applied thereto in one direction and to block rotation of the first portion when force is applied thereto in a second direction. A shear pin or other suitable releasing mechanism may be provided to releasably couple the first portion and the second portion aligned longitudinally with each other. The shear pin and pivot pin are preferably oriented such that during a head-on impact with the end of the associated guardrail facing oncoming traffic, the shear pin will fail and allow the upper section to rotate relative to the lower section and thus minimize damage to the impacting vehicle. For some applications, a release bar or push bar may be attached to the lower section to assist with disengagement of the upper section from the lower section during such rotation of the upper section. During a rail face impact with the associated guardrail, the same orientation of the shear pin and the pivot pin prevents the upper section from rotating relative to the lower section. Thus, the breakaway support post will buckle or yield during a head-on impact to minimize damage to an impacting vehicle and will remain intact to redirect an impacting vehicle back onto the associated roadway after a rail face impact.
Technical advantages of the present invention include providing breakaway support posts which are easier to initially install and to repair as compared to wooden breakaway support posts. Major portions of each breakaway support post may be fabricated from standard, commercially available steel I-beams using conventional metal bending and stamping techniques in accordance with teachings of the present invention. One or more metal soil plates may be attached to each breakaway support post to further enhance desired characteristics of yielding or buckling during head-on impact with one end of an associated guardrail to minimize damage to an impacting vehicle and to securely anchor the associated guardrail to redirect an impacting vehicle back onto the adjacent roadway after a rail face impact. Breakaway support posts incorporating teachings of the present invention may be used with a wide variety of guardrail end treatments having various types of energy absorbing assemblies located at or near the end of the associated guardrail facing oncoming traffic. For many applications, breakaway support posts may be satisfactorily installed adjacent to the edge of a roadway without the use of steel foundation tubes and/or concrete foundations typically associated with installing wooden breakaway support posts and other types of breakaway support posts.
A further aspect of the present invention includes providing guardrail support posts having a first portion or upper section attached or coupled, at least in part, by a frangible connection, to a second portion or lower section. The support post and frangible connection may be oriented in accordance with teachings of the present invention to resist impact by a motor vehicle from one direction (strong direction), and to yield to impact by a motor vehicle from another direction (weak direction). Preferably, the fragile connection allows the upper portion of the post to deflect slightly and then break off of the lower portion, thus minimizing lifting of the impacting vehicle into the air.
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 written description taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a schematic drawing showing an isometric view with portions broken away of a highway guardrail system having a breakaway support post with a guardrail mounted thereon in accordance with one embodiment of the present invention;
FIG. 2 is a schematic drawing in elevation with portions broken away showing a side view of the highway guardrail system of FIG. 1;
FIG. 3 is a schematic drawing in section of the breakaway support post taken along lines 3 — 3 of FIG. 2;
FIG. 4 is a schematic drawing showing an isometric view with portions broken away of a highway guardrail system having a breakaway support post with a guardrail mounted thereon in accordance with another embodiment of the present invention;
FIG. 5 is a schematic drawing in elevation with portions broken away showing a side view of the breakaway support post of FIG. 4 in its first position;
FIG. 6 is a schematic drawing in elevation with portions broken away showing a side view of the breakaway support post of FIG. 5 rotating from its first position to a second position in response to a force applied to the breakaway support post in one direction corresponding with an impact by a vehicle with one end of the associated guardrail;
FIG. 7 is a schematic drawing showing an isometric view with portions broken away of a highway guardrail system having a breakaway support post with a guardrail mounted thereon in accordance with a further embodiment of the present invention;
FIG. 8 is a schematic drawing in elevation with portions broken away showing a side view of the highway guardrail system of FIG. 7;
FIG. 9 is a schematic drawing in section of the breakaway support post taken along lines 9 — 9 of FIG. 8;
FIG. 10 is a schematic drawing showing an isometric view with portions broken away of a highway guardrail system having a breakaway support post with a guardrail mounted thereon in accordance with another embodiment of the present invention;
FIG. 11 is a schematic drawing in elevation with portions broken away showing a side view of a breakaway support post analogous to the breakaway support post of FIG. 10 rotating from its first position to a second position and separating in response to a force applied to the breakaway support post in one direction corresponding with an impact by a vehicle with one end of the associated guardrail;
FIG. 12 is a schematic drawing showing an exploded, isometric view with portions broken away of an alternative embodiment of breaker bars suitable for use with the guardrail system illustrated in FIGS. 10 and 11;
FIG. 13 is a schematic drawing in elevation with portions broken away showing a side view of the breakaway support post of FIG. 10 utilizing the breaker bars of FIG. 12 and rotating from its first position to a second position and separating in response to a force applied to the breakaway support post in one direction corresponding with an impact by a vehicle with one end of the associated guardrail;
FIG. 14A is a schematic drawing in elevation with portions broken away showing a detail side view of a breakaway support post incorporating a further embodiment of the present invention;
FIG. 14B is a schematic drawing in elevation with portions broken away showing another side view of the breakaway post of FIG. 14A;
FIG. 15A is a schematic drawing in elevation with portions broken away showing a detail side view of a breakaway post in accordance with still another embodiment of the present invention;
FIG. 15B is a schematic drawing in elevation with portions broken away showing the upper portion and the lower portion of the breakaway support post of FIG. 15A disconnected from each other;
FIG. 15C is a schematic drawing in elevation with portions broken away showing another side view of the breakaway support post of FIG. 15B; and
FIG. 16 is a schematic drawing in elevation with portions broken away showing a side view of the breakaway support post of FIG. 15A rotating from its first position to a second position in response to a force supplied to the breakaway support post in one direction corresponding with an impact by a vehicle with one end of an associated guardrail.
DETAILED DESCRIPTION OF THE INVENTION
The preferred embodiments of the present invention and its advantages are best understood by referring to the FIGS. 1 through 16 of the drawings, like numerals being used for like and corresponding parts of the various drawings.
Portions of highway guardrail system 20 incorporating one embodiment of the present invention are shown in FIGS. 1, 2 and 3 . Portions of highway guardrail systems 120 , 220 , and 320 incorporating alternative embodiments of the present invention are shown in FIGS. 4 through 13. Breakaway support posts incorporating further embodiments of the present invention are shown in FIGS. 14A through 16. Highway guardrail systems 20 , 120 , 220 , and 320 are typically installed along the edge of a highway or roadway (not expressly shown) adjacent to a hazard (not expressly shown) to prevent a vehicle (not shown) from leaving the associated highway or roadway.
Guardrail systems 20 , 120 , 220 , and 320 are primarily designed and installed along a highway to withstand a rail face impact from a vehicle downstream from an associated end treatment. Various types of guardrail end treatments (not expressly shown) are preferably provided at the end of guardrail 22 facing oncoming traffic. Examples of guardrail end treatments satisfactory for use with the present invention are shown in U.S. Pat. No. 4,655,434 entitled Energy Absorbing Guardrail Terminal; U.S. Pat. No. 4,928,928 entitled Guardrail Extruder Terminal; and U.S. Pat. No. 5,078,366 entitled Guardrail Extruder Terminal. Such guardrail end treatments extend substantially parallel with the associated roadway. U.S. Pat. No. 4,678,166 entitled Eccentric Loader Guardrail Terminal shows a guardrail end treatment which flares away from the associated roadway. U.S. Pat. Nos. 4,655,434; 4,928,928; 5,078,366; and 4,678,166 are incorporated herein by reference. When this type of guardrail end treatment is hit by a vehicle, the guardrail will normally release from the associated support post and allow the impacting vehicle to pass behind downstream portions of the associated guardrail. However, breakaway support posts incorporating teachings of the present invention may be used with any guardrail end treatment or guardrail system having satisfactory energy-absorbing characteristics for the associated roadway and anticipated vehicle traffic.
Support posts 30 , 130 , 230 , 330 and 530 have a strong direction and a weak direction. When a post is subjected to an impact from the strong direction, the post exhibits high mechanical strength. The strong direction is typically oriented perpendicular to the guardrail. Thus, when the post is impacted by a vehicle in the strong direction (such as when the vehicle impacts the face of the guardrail), the post will remain intact and standing, and the vehicle will be redirected back onto the road. When the post is subjected to an impact from the weak direction, the post exhibits low mechanical strength. The weak direction is typically oriented parallel to the guardrail. Thus, when the post is impacted by a vehicle in the weak direction (such as when the vehicle impacts the end of the guardrail), the portion of the post that is substantially above the ground will either break off or bend over, so as to avoid presenting a substantial barrier to the vehicle. Preferably, the upper portion of the post will deflect slightly and then break off, in order to minimize lifting of the impacting vehicle into the air.
One or more support posts 30 , 130 , 230 , 330 , and 530 are preferably incorporated into the respective guardrail end treatment to substantially minimize damage to a vehicle during a head-on impact with the end of guardrail 22 facing oncoming traffic. The number of support posts 30 , 130 , 230 , 330 and 530 and the length of guardrail 22 may be varied depending upon the associated roadway, the hazard adjacent to the roadway requiring installation of highway guardrail system 20 , 120 , 220 or 320 , anticipated vehicle traffic on the associated roadway, and the selected guardrail end treatment. As discussed later in more detail, breakaway support posts 30 , 130 , 230 , 330 and 530 will securely anchor guardrail 22 during a rail face impact or side impact with guardrail 22 to redirect an impacting vehicle back onto the associated roadway. Support posts 30 , 130 , 230 , 330 and 530 will yield or buckle during a head-on impact with the end of guardrail 22 without causing excessive damage to an impacting vehicle.
Support posts 30 , 130 , 230 , 330 and 530 may be fabricated from various types of steel alloys or other materials with the desired strength and/or breakaway characteristics appropriate for the respective highway guardrail system 20 , 120 , 220 , and 320 . For some applications, a breakaway support post incorporating teachings of the present invention may be fabricated from ceramic materials or a mixture of ceramic and metal alloys which are sometimes referred to as cermets.
Portions of breakaway support posts 30 , 130 , 230 , 330 and 530 , as shown in FIGS. 1-16, have the general configuration associated with a steel I-beam. Alternatively, the teachings of the present invention may be incorporated into a breakaway support post having a generally hollow or solid, rectangular, square or circular cross section.
Breakaway support posts 30 , 130 , 230 , 330 and 530 as shown in FIGS. 1-16, have respective upper portions and lower portions with approximately the same general cross-section. However, for some applications, the upper portion of a breakaway support post incorporating teachings of the present invention may have a cross-section which is substantially different from the cross-section of the associated lower portion. For example, the upper portion may have the general configuration associated with an I-beam, while the associated lower portion may have a general configuration associated with either a hollow or solid cylindrical post or a hollow or solid square post.
In FIGS. 1, 2 , 4 , 7 and 10 , highway guardrail systems 20 , 120 , 220 and 320 are shown having a typical deep W-beam twelve (12) gauge type guardrail 22 . For some applications, a thrie beam guardrail may be satisfactorily used. Other types of guardrails, both folded and non-folded, may be satisfactorily used with breakaway support posts 30 , 130 , 230 , 330 and 530 incorporating the teachings of the present invention. Breakaway support posts 30 , 130 , 230 , 330 and 530 may sometimes be described as direct drive support posts.
Various techniques which are well known in the art may be satisfactorily used to install breakaway support posts 30 , 130 , 230 , 330 and 530 depending upon the type of soil conditions and other factors associated with the roadway and the hazard requiring installation of respective highway guardrail systems 20 , 120 , 220 , and 320 . For many applications, breakaway support posts 30 , 130 , 230 , 330 and 530 may be simply driven into the soil using an appropriately sized hydraulic and/or pneumatic driver. As a result, breakaway support posts 30 , 130 , 230 , 330 and 530 may be easily removed from the soil using an appropriately sized crane or other type of pulling tool. For many applications, breakaway posts 30 , 130 , 230 , 330 and 530 may be satisfactorily used to install guardrail 22 adjacent to an associated roadway without the use of metal foundation tubes or other types of post-to-ground installation systems such as concrete with a steel slip base support. U.S. Pat. No. 5,503,495, entitled Thrie-Beam Terminal With Breakaway Post Cable Release, shows one example of a breakaway support post with this type of foundation.
As shown in FIGS. 1, 2 and 3 , breakaway support post 30 includes elongated body 32 defined in part by web 34 with flanges 36 and 38 attached thereto. Elongated body 32 may be formed by cutting a steel I-beam (not expressly shown) into sections having the desired length for elongated body 32 . A pair of elongated slots 40 and 42 are preferably formed in flange 36 on opposite sides of web 34 . Similarly, a pair of slots 44 and 46 are preferably formed in flange 38 on opposite sides of web 34 . Slots 40 , 42 , 44 and 46 are formed intermediate first end 31 and second end 33 of breakaway support post 30 . Slots 40 , 42 , 44 and 46 define in part a frangible or yieldable connection between an upper portion and a lower portion of support post 30 .
The length of breakaway support post 30 and the location of slots 40 , 42 , 44 and 46 will depend upon various factors including soil conditions and the anticipated amount of force that will be applied to breakaway support post 30 during a rail face impact with guardrail 22 and during a head-on impact with one end of guardrail 22 . For the embodiment shown in FIGS. 1, 2 and 3 , slots 40 , 42 , 44 and 46 are formed in breakaway post 30 at a location corresponding approximately with the anticipated ground line when breakaway support post 30 is properly installed adjacent to the associated roadway.
For one application, elongated body 32 may be formed from a standard steel I-beam with flanges 36 and 38 having a nominal width of four (4″) inches and web 34 having a nominal width of six (6″) inches. Slots 40 , 42 , 44 and 46 have a generally elongated oval configuration approximately six (6″) inches in length and one fourth (¼″) inch in width. Slots 40 , 42 , 44 , and 46 are positioned intermediate ends 31 and 33 to cause local buckling of the associated breakaway post 30 when properly installed.
For the embodiments shown in FIGS. 1 and 2, block 48 is disposed between breakaway support post 30 and guardrail 22 . Block 48 may sometimes be referred to as a “blockout.” For other applications, guardrail 22 may be directly mounted adjacent to end 31 of breakaway support post 30 . During a rail face impact between a vehicle and guardrail 22 downstream from the associated end treatment, block 48 provides a lateral offset between breakaway support post 30 and guardrail 22 . The distance and direction of the lateral offset is selected to prevent the wheels (not shown) of an impacting vehicle from striking breakaway support post 30 during the rail face impact.
For the embodiment shown in FIGS. 1, 2 and 3 , breakaway support post 30 includes soil plates 52 and 54 which are attached to the exterior of respective flanges 36 and 38 adjacent to the portion of breakaway support post 30 which will be inserted into the soil adjacent to the associated roadway. For this embodiment, soil plates 52 and 54 have approximately the same thickness as web 34 and are generally aligned with web 34 on opposite sides of respective flanges 36 and 38 .
Breakaway support post 30 is preferably installed with web 34 extended approximately perpendicular from guardrail 22 and flanges 36 and 38 extending generally parallel with guardrail 22 . By aligning web 34 approximately perpendicular to guardrail 22 , breakaway support post 30 will provide sufficient support to resist large forces associated with a rail face impact or rail face impact between a vehicle and guardrail 22 . As a result of forming slots 40 , 42 , 44 and 46 in respective flanges 36 and 38 and orienting flanges 36 and 38 generally parallel with guardrail 22 , a head-on impact from a vehicle with one end of guardrail 22 will result in buckling or yielding of breakaway support post 30 .
The amount of force required to buckle and/or fracture breakaway support post 30 may be decreased by increasing the size and/or the number of slots 40 , 42 , 44 and 46 formed in respective flanges 36 and 38 . Alternatively, reducing the number and/or size of slots 40 , 42 , 44 and 46 will result in a larger amount of force required to buckle or yield breakaway support post 30 .
The orientation of soil plates 52 and 54 , relative to a head-on impact with one end of guardrail 22 will prevent twisting or tilting of breakaway support post 30 during the head-on impact. The additional support provided by soil plates 52 and 54 will increase the reliability of breakaway support post 30 yielding or buckling at the general location of slots 40 , 42 , 44 and 46 in response to a selected amount of force applied adjacent to end 31 of post 30 in a first direction corresponding to the direction of a head-on impact with one end of guardrail 22 . Soil plate 52 includes a generally triangular portion 56 which extends above elongated slots 40 , 42 , 44 and 46 to provide additional support for breakaway support post 30 and guardrail 22 during a rail face impact.
For some applications, the length of elongated body 32 may be increased such that soil plates 52 and 54 are no longer required to provide additional support for the resulting breakaway support post 30 . Eliminating soil plates 52 and 54 will allow a hydraulic or pneumatic hammer to more quickly install the associated breakaway support post 30 and a crane or hydraulic/pneumatic pulling tool to more easily remove a damaged breakaway support post 30 . Alternatively, breakaway support post 30 could be inserted into an appropriately sized concrete foundation and/or metal sleeve. Soil plates, concrete foundation, sleeves and other anchoring devices can be used in any of the posts of the present invention.
For some applications, it may be preferable to form a breakaway support post in accordance with teachings of the present invention from an elongated body having a generally hollow, rectangular or square configuration (not shown). Slots 40 , 42 , 44 and 46 may then be formed in opposite sides of the resulting breakaway support post which are aligned generally parallel with the associated guardrail similar to flanges 36 and 38 . The other pair of opposite sides preferably extend approximately normal from the associated guardrail similar to web 34 .
When force is applied adjacent to end 31 of breakaway support post 30 in a second direction corresponding with a rail face impact between a vehicle and guardrail 22 , web 34 will resist buckling of breakaway support post 30 and provide sufficient support to redirect the impacting vehicle back onto the roadway.
Breakaway support post 130 , as shown in FIGS. 4, 5 and 6 , includes elongated body 132 having an upper portion 142 and a lower portion 144 which are rotatably coupled with each other. For the embodiment of the present invention shown in FIGS. 4, 5 and 6 , rotatable coupling assembly 140 is preferably installed intermediate ends 131 and 133 of elongated body 132 . Upper portion 142 and lower portion 144 each have a general configuration of an I-beam defined in part by respective webs 134 and flanges 136 and 138 . Upper portion 142 and lower portion 144 may be formed from a conventional steel I-beam in the same manner as previously described.
For the embodiment of the present invention as shown in FIGS. 4, 5 and 6 , rotatable coupling assembly 140 includes a first generally U-shaped bracket 150 attached to one end of upper portion 142 , opposite end 131 and a second U-shaped bracket 152 attached to the end of lower portion 144 opposite from end 133 . Brackets 150 and 152 each have a generally open, U-shaped configuration with extensions substantially parallel to the flanges and protruding beyond the respective webs. A portion of bracket 150 is preferably sized to fit within a corresponding portion of bracket 152 . Pivot pin 154 extends laterally through adjacent portions of bracket 150 and 152 in a direction which is generally parallel with webs 134 . The resulting breakaway support post 130 is preferably installed with webs 134 and pivot pin 154 extending generally normal from the associated guardrail 22 . As a result of this orientation, webs 134 and rotatable coupling assembly 140 including pivot pin 154 allow breakaway support post 130 to sufficiently support guardrail 22 during a rail face impact to redirect an impacting vehicle back onto the associated roadway.
In FIGS. 4, 5 and 6 , respective webs 134 of upper portion 142 and lower portion 144 are shown generally aligned parallel with each other. For some applications, the orientation of lower portion 144 may be varied with respect to upper portion 142 such that web 134 of lower portion 144 extends approximately parallel with guardrail 22 . The attachment of brackets 150 and 152 with their respective upper portion 142 and lower portion 144 may be modified to accommodate various orientations of lower portion 144 relative to upper portion 142 .
Depending upon the length of lower portion 144 and the type of soil conditions, soil plates 162 and 164 may be attached to lower portion 144 extending from respective flanges 136 and 138 . For some applications, lower portion 144 may be substantially longer than upper portion 142 . As a result of increasing the length of lower portion 144 , the use of soil plates 162 and 164 may not be required.
Shear pin 156 is laterally inserted through adjacent portions of brackets 150 and 152 offset from pivot pin 154 . Shear pin 156 preferably has a relatively small cross-section as compared to pivot pin 154 . As a result, when a vehicle impacts with one end of guardrail 22 , shear pin 156 will break and allow upper portion 142 to rotate relative to lower portion 144 as shown in FIG. 6 . Shear pin 156 maintains upper portion 142 and lower portion 144 generally aligned with each other during installation of the associated breakaway support post 30 .
The amount of force required to fracture or break shear pin 156 may be determined by a variety of parameters such as the diameter of shear pin 156 , the type of material used to fabricate shear pin 156 , the number of locations (either along a single pin or with plural pins) that must be sheared, and the distance between shear pin 156 and pivot pin 154 . As discussed later in more detail with respect to breakaway support post 530 , as shown in FIGS. 15A through 16, rotatable coupling 540 may be modified to allow upper portion 542 to disconnect and separate from lower portion 544 .
Various types of releasing mechanisms other than shear pin 156 may be satisfactorily used to maintain upper portion 142 and lower portion 144 generally aligned with each other during normal installation and use of the associated breakaway support post 130 . A wide variety of shear bolts, shear screws and/or breakaway clamps may be used to releasably attach first bracket 150 with second bracket 152 .
When a vehicle impacts with one end of guardrail 22 , force is applied in a first direction to upper portion 142 and will break shear pin 156 . As a result, upper portion 142 will then rotate relative to lower portion 144 as shown in FIG. 6 .
FIGS. 7, 8 and 9 show portions of highway guardrail system 220 which includes breakaway support post 230 and guardrail 22 . Breakaway support post 230 includes elongated body 32 and is similar in both design and function with breakaway support post 30 . One difference between breakaway support posts 30 and 230 is the replacement of soil plates 52 and 54 by soil plates 254 and 256 . As best shown in FIGS. 8 and 9, fastener assembly 160 may be used to attach soil plate 254 with elongated body 32 . Fastener assembly 160 includes threaded bolt 163 , hollow sleeve or spacer 168 and nut 165 . The use of soil plate 254 and fastener assembly 160 eliminates some of the welding steps associated with attaching soil plates 52 and 54 to breakaway support post 30 .
Soil plate 254 has a generally rectangular configuration. The length, width and thickness of soil plates 254 may be varied depending upon the intended application for the associated breakaway post 230 and the anticipated soil conditions adjacent to the associated roadway. An appropriately sized hole is preferably formed in the mid-point of soil plate 254 and bolt 162 inserted therethrough. The head 166 of bolt 163 is disposed on the exterior of soil plate 254 . Spacer or hollow sleeve 168 is then fitted over the threaded portion of bolt 162 extending from soil plate 254 opposite from head 166 . A corresponding hole is preferably formed in web 34 at the desired location for soil plate 254 . Bolt 163 is inserted through the hole in web 34 and nut 165 attached thereto.
For some applications, a smaller soil plate 256 may be attached to the exterior of flange 36 adjacent to web 34 . The dimensions and location of soil plate 256 may be varied depending upon the anticipated application including soil conditions, associated with highway guardrail system 220 .
FIGS. 10 and 11 illustrate portions of highway guardrail system 320 , which includes breakaway support post 330 and guardrail 22 . FIG. 11 illustrates an embodiment of support post 330 having narrower breaker bars 350 and 352 than those illustrated in FIG. 10 . Support post 330 includes an elongated body 332 having an upper portion 342 and a lower portion 344 . Upper portion 342 and lower portion 344 each have the general configuration of a steel I-beam similar to elongated body 32 of breakaway support post 30 .
Upper portion 342 and lower portion 344 are defined in part by respective webs 334 and flanges 336 and 338 . Upper portion 342 and lower portion 344 may be formed from a conventional steel I-beam in the same manner as previously described. Lower portion 344 may be positioned substantially within the ground. Alternatively, lower portion 344 could be inserted into a concrete foundation and/or a metal sleeve which have been previously installed at the desired roadside location.
Upper portion 342 and lower portion 344 are provided with breaker bars 350 and 352 . In the embodiment shown in FIG. 10, flanges 336 and 338 in upper portion 342 are connected to breaker bar 350 , by for example, welds. Flanges 336 and 338 in lower portion 344 may be connected to breaker bar 352 in an analogous fashion. Other suitable connection techniques may be used to couple flanges 336 and 338 of upper and lower portions 342 and 344 to breaker bars 350 and 352 , respectively. For example, as illustrated in FIG. 11, tie straps 362 and 364 may be used, particularly in an embodiment where breaker bars 350 and 352 are narrower than flanges 336 and 338 , as is the case in FIG. 11 . For some applications, breaker bar 352 may be directly attached to a concrete foundation to eliminate the use of lower portion 344 .
Breaker bars 350 and 352 are connected to each other by fasteners 358 , which is illustrated by a simple nut and bolt; however, other suitable fasteners may be used with this aspect of the invention. Breaker bars 350 and 352 are preferably formed with chamfered or tapered surfaces 354 . Chamfered surfaces 354 cooperate with each other to define in part a notch or gap between adjacent portions of breaker bars 350 and 352 . Chamfered surfaces 354 extend generally parallel with each other in a direction generally normal to guardrail 22 . An imaginary line 359 can also be drawn through fasteners 358 in the same general direction parallel with chamfered surfaces 354 and normal to guardrail 22 . Imaginary line 359 corresponds with a strong direction for breakaway support posts 330 in which breakaway support post 330 exhibits high mechanical strength. There is a notch or gap on each side of the imaginary line 359 .
Chamfered surfaces 354 cooperate with each other to allow upper portion 342 to pivot relative to lower portion 344 during a head-on impact, as illustrated in FIG. 11 . Such pivoting may cause fasteners 358 to break, separating upper portion 342 from lower portion 344 and may therefore substantially minimize damage to a vehicle during a head-on impact with the end of guardrail 22 facing oncoming traffic. The orientation of chamfered surfaces 354 and fasteners 358 relative to each other further define a weak direction for breakaway support post 330 in which support post 330 exhibits low mechanical strength. However, chamfered surfaces 354 do not reduce the ability of guardrail 320 to redirect an impacting vehicle back onto the associated roadway during a rail face impact with guardrail 22 .
FIG. 12 is a schematic drawing showing an exploded isometric view with portions broken away of an alternative embodiment of breaker bars suitable for use in guardrail system 320 . Breaker bars 450 and 452 perform similar functions as breaker bars 350 and 352 . Breaker bar 450 includes a flat plate 453 having a protruding member or projection 454 . Breaker bar 452 includes a flat plate 455 having a protruding member or projection 456 . Flat plates 453 and 455 are each formed with two or more apertures 458 for receiving a connecting member, such as mechanical fastener 358 , for attaching breaker bars 450 and 452 with each other. The use of protruding members or projections 454 and 456 allows upper portion 342 to pivot relative to lower portion 344 during a head-on impact, as illustrated in FIG. 13 . Impact from the weak direction for support post 330 will result in bending and preferably failure of connecting members 358 . Failure of connecting members 358 separates upper portion 342 from lower portion 344 and may, therefore, substantially minimize damage to a vehicle during a head-on impact with the end of guardrail 22 facing oncoming traffic. However, protruding members or projections 454 and 456 do not reduce the ability of guardrail 22 to redirect an impacting vehicle back onto the associated roadway during a rail face impact.
FIGS. 14A and 14B are schematic drawings with portions broken away showing an alternative embodiment of a frangible or yieldable connection satisfactory for releasably coupling upper portion 342 with lower portion 344 of support post 330 . For this embodiment, breaker bars 450 and 452 are substantially the same as previously described with respect to the embodiment shown in FIG. 13, except for the elimination of protruding members or projections 454 and 456 . A pair of elongated connecting members 458 and a plurality of nuts 460 are preferably provided to maintain a desired gap or spacing between breaker bars 450 and 452 . For the embodiment shown in FIGS. 14A and 14B, elongated connecting members 458 and nuts 460 have matching threads. However, various types of mechanical fasteners and connecting members may be satisfactorily used to position upper portion 332 of support post 330 relative to lower portion 344 .
As a result of incorporated teachings of the present invention, support post 330 has relatively low mechanical strength with respect to impact from a direction generally normal to an imaginary line 359 (see FIG. 10) extending through connecting members 358 or 458 as appropriate. This direction may be referred to as the “weak direction.” Connecting members 358 and 458 are preferably formed from materials which will yield and preferably fracture or break to allow upper portion 342 to separate from lower portion 344 . Since there is a gap between the breaker bars 350 and 352 or breaker bars 450 and 452 to either side of line 359 in the weak direction, connecting members 358 or 458 as appropriate will carry substantially all of the force or load from an impact in the weak direction.
When support post 330 is impacted from another direction, the resulting force, or at least a component of the resulting force, will tend to place one of the associated connecting members 358 or 458 as appropriate in tension, and will tend to place the other connecting member 358 or 458 as appropriate in compression. Therefore, the mechanical strength of the frangible connection between upper portion 342 and lower portion 344 is substantially greater in the strong direction as compared with an impact from the weak direction. The strongest direction for an impact with support post 330 is from a direction substantially perpendicular to the surface of flanges 338 and 336 and parallel with web 334 (the strong direction). The weakest direction for an impact with support post 330 is in a direction which is substantially perpendicular to web 334 and parallel with flanges 336 and 338 .
Spacers with various forms and configurations may be used to separate breaker bars 350 and 352 or 450 and 452 from each other as desired. For the embodiment shown in FIGS. 10 and 11, tapered surfaces or chamfered surfaces 354 form the necessary spacers as integral components of breaker bars 350 and 352 . For the embodiment shown in FIGS. 12 and 13, protruding members or projections 454 and 456 function as spacers to form the desired gap. For the embodiment shown in FIGS. 14A and 14B, nuts 460 cooperate with connecting members 458 to function as spacers to form the desired gap. Nuts 460 that are between breaker bars 450 and 452 may also be referred to as “stops.”
For some applications, upper portion 342 and lower portion 344 of support post 330 may be coupled with each other by only one connecting member 358 or 458 . Alternatively, more than two connecting members 358 or 458 may be used depending upon the anticipated application for the associated support post 330 . For some applications, one connecting member 358 or 458 may be provided on the side of support post 330 which is immediately adjacent to guardrail 22 . The associated breaker bars 350 and 352 or 450 and 452 will contact each other on the opposite side of the post, whereby the single connecting member 358 or 458 as appropriate will provide sufficient strength for support post 330 to withstand rail face or side impact with the associated guard rail 22 .
Support post 530 , as shown in FIGS. 15A through 16, is substantially similar to previously described support post 130 , except rotatable coupling assembly 140 has been replaced by rotatable coupling assembly or releasable hinge 540 . The embodiment shown in FIGS. 15A, 15 B, 15 C and 16 provides for the separation of upper portion 142 from lower portion 144 . Thus, upper portion 142 will not lift an impacting vehicle. Support post 530 may be formed in part by upper portion 142 and lower portion 144 as previously described with respect to support post 130 . Coupling assembly or releasable hinge 540 preferably includes a first generally U-shaped bracket 550 attached to one end of upper portion 142 , and a second U-shaped bracket 552 attached to an adjacent end of lower portion 144 . Brackets 550 and 552 each have a generally open, U-shaped configuration. A portion of bracket 550 is preferably sized to fit over a corresponding portion of bracket 552 .
Pivot pin 554 preferably extends through adjacent portions of brackets 552 in a direction which is generally parallel with webs 134 . Alternatively, pivot pin 554 may be replaced by generally round projections extending from opposite sides of bracket 552 . Bracket 550 preferably includes a pair of slots 572 formed in opposite sides thereof. Slots 572 are preferably sized to releasably engage respective portions of pin 554 which extend from bracket 552 . Slots 572 cooperate with pivot pin 554 to allow rotation of upper portion 142 relative to lower portion 144 , and to allow disengagement of upper portion 142 from lower portion 144 .
The resulting breakaway support post 530 is preferably installed with webs 134 and pivot pin 554 extending generally normal from the associated guardrail 22 . As a result of this orientation, webs 134 and releasable hinge 540 , including pivot pin 554 , allow support post 530 to adequately support guardrail 22 during a rail face impact to redirect an impacting vehicle back onto the associated roadway.
Shear pin 556 is preferably inserted through adjacent portions of brackets 550 and 552 offset from pivot pin 554 . Shear pin 556 maintains upper portion 142 and lower portion 144 generally aligned with each other during installation of the associated breakaway support post 530 . Shear pin 556 preferably has a relatively small cross-section as compared to pivot pin 554 . As a result, when a vehicle impacts with one end of guardrail 22 , shear pin 556 will break and allow upper portion 142 to rotate relative to lower portion 144 as shown in FIG. 16 . For some applications, push bar 580 is preferably attached to and extends between opposite sides of bracket 552 . The location of push bar 580 on bracket 552 is selected to assist disengagement of slot 572 from pivot pin 554 as upper portion 142 rotates relative to lower portion 144 . See FIG. 16 .
The amount of force required to fracture or break shear pin 556 may be determined by a variety of parameters such as the diameter of shear pin 556 , the type of material used to fabricate shear pin 556 , the number of locations (either along a single pin or with plural pins) that must be sheared, and the distance between shear pin 556 and pivot pin 554 .
Various types of releasing mechanisms other than shear pin 556 may be satisfactorily used to maintain upper portion 142 and lower portion 144 generally aligned with each other during normal installation and use of the associated breakaway support 530 . A wide variety of shear bolts, shear screws, frangible disks, and/or breakaway clamps may be used to releasably attach first bracket 550 with second bracket 552 .
When a vehicle impacts with one end of guardrail 22 , force is applied in a first direction (weak direction) to upper portion 142 and will break shear pin 556 . As a result, upper portion 142 will then rotate relative to lower portion 144 as shown in FIG. 16 . When portions of bracket 550 contact push bar 580 , slots 572 will disengage from pivot pin 554 and release upper portion 142 from lower portion 144 .
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 hereto without departing from the spirit and scope of the invention as defined by the following claims. | A support post for a guardrail which resists impact by a motor vehicle from one direction (strong direction) and yields to impact by a motor vehicle from another direction (weak direction). The support post is adapted to receive the guardrail such that the rail face of the guardrail runs generally perpendicular to the strong direction such that the support post resists an impact on the rail face of the guardrail and yields to an impact force on the end of the guardrail. | 4 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an antiwear coating especially for components which are subject to erosion under mechanical stress, in particular for gas turbine components, which consists of at least two different individual layers which have been applied in a multiply alternating manner with one another to a surface to be coated of a component.
2. Discussion of Background Information
Gas turbine components are provided with an antiwear layer for protection against wear, especially erosion and corrosion. This antiwear layer consists of a plurality of individual layers composed of different materials, as is known from the document DE 10 2004 001 392.6. Here, a metallic layer is firstly applied to a component in order to make good bonding of the antiwear layer to the metallic substrate material possible. This is followed by a metal alloy and a gradated metal-ceramic material. This multilayer system is concluded by a ceramic layer. This multilayer system can also be deposited a plurality of times on top of the first multilayer system, always commencing with a metallic layer to achieve better bonding to the metallic substrate material and ending with a ceramic layer on the surface. In addition, a bonding layer can be inserted between the first multilayer system and the component.
In general, such multilayer systems based on this principle are made up of hard (main) and soft (intermediate) layers. The main layers have a high erosion resistance and the intermediate layers have a high ductility. As a result, cracks which form in the case of overloading in the multilayer structure are stopped in the ductile intermediate layers by blunting of the crack tips.
To prevent erosion, structuring the hard ceramic layers of a multilayer system is known from the document DE 10 2006 001 864.8. Such ceramic layers are segmented in the vertical direction in a columnar manner in order to prevent detachment of relatively large regions of the layer during particle erosion attack. Here, the columnar segmentation is in the form of columns or stems or fibers. The interfaces between the columns of the layers segmented in a columnar fashion prevent the growth of microcracks in the direction parallel to the surface which can be caused during erosive stress. However, it is a disadvantage that cracks in the vertical direction can be propagated unhindered along the interfaces. When a component is stressed, these interfaces between columns act as micronotches or initial microcracks. In the case of severe overstressing, the ductile intermediate layers can no longer stop the arriving microcracks and the latter grow into the substrate material. The microcrack formed under tensile stress can propagate far into the substrate material and lead to premature failure of the component. This has the substantial disadvantage that the life of a component is considerably reduced.
It is therefore an object of the invention to provide an antiwear layer which firstly increases the life of a component and secondly prevents microcrack formation.
SUMMARY OF THE INVENTION
The object of the invention is achieved by an antiwear coating as set forth in the independent claim(s). Further advantageous embodiments of the invention are specified in the dependent claims.
The invention relates to an antiwear coating which is especially suitable for components which are subject to erosion under mechanical stress, in particular for gas turbine components, and comprises at least two different individual layers which have preferably been applied in an alternating manner (in the case of more than two layers) to a surface to be coated of a component. however, in contrast to the known antiwear layers, the individual layers in the antiwear coating of the invention are formed firstly by a known ceramic main layer and secondly by a pseudoductile, non-metallic intermediate layer. the pseudoductile, non-metallic intermediate layer is, as will be shown below, configured in such a way that energy is withdrawn from cracks which grow in the direction of the substrate material by crack branching in the pseudoductile, non-metallic intermediate layer, so that crack growth can be slowed or stopped.
A corresponding antiwear coating can likewise be configured as a multilayer coating, with the pseudoductile non-metallic intermediate layer and the ceramic main layer which has a brittle and hard property profile being able to be arranged alternately a number of times above one another.
In particular, the pseudoductile, non-metallic intermediate layer may be arranged directly on the component to be coated, while a hard, ceramic main layer may be arranged at the surface of the antiwear coating.
In an embodiment of the invention, the pseudoductile, non-metallic intermediate layer may comprise a material having weak bonds, preferably materials having a sheet structure or a hexagonal lattice structure which make easy shearing-off of the material possible or comprise easily activatable sliding planes, with the sheet planes or basal planes of the material or the easily activatable sliding planes being arranged parallel to the surface of the component. Thus, arsenic and antimony, for example, are suitable materials since they have a sheet structure, and also, for example, graphite, molybdenum disulfide and/or hexagonal boron nitride since they have a hexagonal lattice structure. The low adhesion between the basal planes or the easy sliding-off of adjacent planes in these materials results in crack deflection, so that the crack spreads out between the basal planes or the planes which can readily slide relative to one another. Since the materials are applied in such a way that the basal planes or the planes which can readily slide relative to one another are aligned parallel to the surface to be coated, crack growth in the direction of the substrate material is avoided.
In a further embodiment of the invention, the pseudoductile, non-metallic intermediate layer may have a multilayer system which has ceramic layers in addition to layers having relatively weak bonding (sliding layers). Materials combinations such as C/TiC, C/SiC, C/ZrC, hexagonal BN/cubic BN and/or hexagonal BN/SiC are suitable for this purpose.
In a further embodiment of the invention, the sublayers in the multilayer system of the pseudoductile, non-metallic intermediate layer may have weak interfaces with one another.
In a further embodiment of the invention, layers having relatively weak bonds (sliding layers) in the multilayer system may have no or minor chemical reactions with ceramic layers in the multilayer system.
In a further embodiment of the invention, layers having relatively weak bonding (sliding layers) and ceramic layers in the multilayer system may have a low surface roughness. This low surface roughness ensures weak mechanical intermeshing between the individual layers.
In a further embodiment of the invention, the pseudoductile, non-metallic intermediate layer may comprise a ceramic material and/or further hard material compounds having deliberately introduced pores. Here, the ceramic material may comprise chromium nitride, titanium nitride and/or compounds therefrom, in particular with further elements such as aluminum or silicon, so that, for example, chromium aluminum nitride or titanium aluminum nitride or chromium silicon nitride or titanium silicon nitride is present.
In a further embodiment of the invention, the pseudoductile, non-metallic intermediate layer may comprise a ceramic and/or hard material compounds having deliberately introduced microcracks which run parallel to the surface. The material may once again comprise chromium nitride, titanium nitride and/or compounds therefrom, in particular with further elements such as aluminum or silicon, and/or further known hard material compounds having a nitride or carbide basis.
In a further embodiment of the invention, the pseudoductile, non-metallic intermediate layer may comprise a ceramic material and/or a hard material compound having deliberately introduced foreign phases.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is illustrated below with the aid of an example and reference to the accompanying drawings. The drawings show, purely schematically,
FIG. 1 crack branching in an intermediate layer according to the invention;
FIG. 2 a sheet structure or basal planes in the hexagonal lattice structure of graphite;
FIG. 3 a structure of the intermediate layer according to the invention as multilayer system;
FIG. 4 a depiction of the intermediate layer according to the invention having pores which stop the cracks;
FIG. 5 a depiction of the intermediate layer according to the invention having microcracks parallel to the surface or to the substrate material;
FIG. 6 a depiction of the intermediate layer according to the invention having deliberately introduced foreign phases.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a substrate material 40 and a multilayer system 39 applied thereto.
Influencing of the properties (e.g. mechanical strength) of the substrate material 40 by cracks which propagate under stress from the multilayer system 39 into the substrate material 40 can be prevented by a specific structure of the individual layers of the multilayer system 39 . The multilayer system 39 has a first intermediate layer 41 , a hard ceramic main layer 45 , a second intermediate layer 42 , a ceramic main layer 46 , a third intermediate layer 43 , a third ceramic main layer 47 , a fourth intermediate layer 44 and a fourth ceramic main layer 48 . The hard ceramic main layers make it possible for the crack to be propagated directly in the direction of the substrate material 40 . The pseudoductile, non-metallic intermediate layers 41 , 42 , 43 , 44 according to the invention in the multilayer system 39 prevent the crack 50 from growing further in the direction of the substrate material 40 and leading to premature damage to the component. Energy is withdrawn from the crack 50 by crack branching in the intermediate layers 41 , 42 , 43 , 44 and the ceramic multilayer system 39 is thereby given pseudoductile behavior.
Materials having a sheet structure are suitable for the intermediate layers 41 , 42 , 43 , 44 . Such a sheet structure is displayed by arsenic and antimony. In addition, hexagonal modifications of carbon can also be used. Thus, a hexagonal lattice structure of graphite can be seen in FIG. 2 . The strength in the planes of the sheets (basal planes 51 ) is, due to atom bonds, greater than perpendicular thereto. However, weak secondary valence forces 52 bring about low adhesion between the basal planes. The basal planes 51 should therefore be oriented parallel to the surfaces of the substrate material. Cracks which go out from the ceramic main layers 45 , 46 , 47 , 48 in the multilayer system 39 will then grow preferentially along the weak bond 52 (between the basal planes 51 ) of the intermediate layer 41 , 42 , 43 , 44 according to the invention. This enables crack deflection and splitting up into many smaller cracks to be achieved, which leads to stopping of the crack.
FIG. 3 schematically shows an intermediate layer 41 , 42 , 43 , 44 according to the invention as multilayer system 57 . The structure of the multilayer 57 is selected so that either layers having relatively weak bonding 55 and/or weak interfaces 58 are present between the sublayers 55 , 56 of the multilayer 57 . The deflection of vertical cracks 50 which go out from the ceramic main layers 45 , 46 , 47 , 48 occurs either at the weak interfaces 58 of the multilayer according to the invention or in sublayers 55 having weak bonds. Weak interfaces 58 can be produced by using suitable material pairs which do not undergo a chemical reaction. A low surface roughness of the individual layers ensures weak mechanical intermeshing and thus also low adhesion.
FIG. 4 schematically shows an embodiment of the intermediate layer 41 , 42 , 43 , 44 according to the invention having pores 59 . The deliberate introduction of pores 59 into the intermediate layer 41 , 42 , 43 , 44 results in cracks which go out from the ceramic main layer 45 , 46 , 47 , 48 of the multilayer system 39 altering the direction of propagation, branching and not growing through to the substrate material 40 . The change in the direction of propagation is brought about by the pores which are joined to one another only via weak material bridges.
FIG. 5 schematically shows an embodiment of the intermediate layer 41 , 42 , 43 , 44 according to the invention having microcracks parallel to the surface or to the substrate material. Microcracks 60 have the same effects as pores 59 . However, they have to be oriented parallel to the surface of the substrate material in order to stop cracks which go out from the ceramic main layer 45 , 46 , 47 , 48 of the multilayer system 39 .
FIG. 6 shows an intermediate layer 41 , 42 , 43 , 44 having deliberately introduced foreign phases 61 . These foreign phases 61 result in cracks which go out from the ceramic main layer 45 , 46 , 47 , 48 of the multilayer system 39 changing the direction of propagation, branching and not growing through to the substrate material 40 . Here, the cracks are deflected either at the weak interface to the foreign phase 62 or by preferential propagation into the foreign phase.
It should be stated that the embodiments in FIG. 4 , in FIG. 5 and in FIG. 6 can be combined with one another. Thus, an intermediate layer 41 , 42 , 43 , 44 can comprise pores, microcracks parallel to the surface or to the substrate material and/or foreign phases. | The invention relates to an anti-wear coating, specifically for components which are subject to erosion under mechanical loading, in particular for gas turbine components, said coating comprising at least two different individual layers which preferably alternate with one another multiply and are applied to a surface of a component which is to be coated. The individual layers comprise a ceramic main layer ( 45, 46, 47, 48 ) and a quasi-ductile, non-metallic intermediate layer ( 41, 42, 43, 44 ). | 2 |
CROSS REFERENCE TO RELATED APPLICATION
This application claims the benefit of U.S. provisional patent application No. 60/316,120, filed Aug. 30, 2001, and entitled “Method of Reducing Air-Rush Noise Created by Throttle Plate”.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to reducing noise in a motor vehicle, and in particular, a new throttle plate and method of design to reduce air rush noise generated as air moves past a partially opened throttle plate into the vehicle intake manifold.
2. Background and Description of the Prior Art
Electronic fuel injection systems in vehicles have replaced carburetor systems in an effort to reduce engine emissions and increase fuel efficiency. When the driver depresses the gas pedal on a fuel injected vehicle, the throttle valve opens inside the throttle body, letting in more air. The air travels through the engine intake manifold, where it mixes with fuel from the fuel injectors and enters the engine cylinders to increase power to the vehicle. When the air rushes through the throttle body into the manifold, increased turbulent air flow is created, which can make significant noise.
Noise reduction has been a major goal of automakers in motor vehicles for the past several years. With global competition in vehicle sales, automakers often try to differentiate their vehicles from the competition by their “sound characteristics.” As major vehicle noises are reduced, other long-standing background noises must be addressed. Air rush noise through the intake system when the throttle plate is opened is one of those noises.
High frequency flow noise can be created when a butterfly valve (the throttle plate) is opened from the fully closed position to some partially open position. Due to its inherent lower material density, this can be especially troublesome in composite-based air intake systems. The convergence of turbulent air streams through the openings created on either side of the throttle plate creates what is described as a ‘whoosh’ noise by customers. The condition can exist at ‘tip-in’ (the rapid opening of the fully closed throttle plate) or at a steady state, part-throttle condition.
Several designs currently exist to reduce the air rush noise in a vehicle. One method is seen in U.S. Pat. No. 5,722,357 issued to Choi. This patent describes a gasket-like piece that is added between the throttle body and the manifold to diffuse the air flow downstream from the throttle plate. Vanes project from the interior of the circular opening to diffuse the air flow and reduce the noise. Since the vanes are not located at the source of noise, this method is less effective at reducing the noise. The addition of these protrusions can also act to partially impede the flow resulting in an increased pressure drop leading to a minor loss of power when the throttle plate is fully open. This method, however, requires an extra component to be installed on every vehicle. This is not cost-effective for mass production.
The use of protrusions downstream of the throttle plate is also discussed in U.S. Pat. No. 5,970,963 issued to Nakase et al. Several different types of protrusions from the downstream side of the throttle valve are discussed. These protrusions severely complicate the die cast tooling necessary to make the throttle body. Slides will need to be added to the die cast tool and extra machining of the casting will be necessary. This adds cost to the component and reduces production volume. The addition of these protrusions can also act to partially impede the flow resulting in an increased pressure drop further leading to a minor loss of power when the throttle plate is fully open.
Adding protrusions to the throttle plate to reduce the air rush noise has been addressed in U.S. Pat. No. 5,881,995 issued to Tse et al. and U.S. Pat. No. 5,465,756 issued to Royalty et al. Both patents describe noise reduction components added to the throttle plate to attenuate the noise. The fins on the designs, however, are of a fixed geometry to the throttle plate. While these will reduce some of the air rush noise, they may not eliminate it in all vehicle models. Manifolds and throttle bodies vary in shape, which changes the fluid dynamics and noise in the vehicles necessitating an adaptable throttle plate design. The subject matter of the above referenced patents may also have reduced power when the throttle plate is fully open due to the pressure drop caused by protrusions of these types. There still exists a need to optimize these protrusions. No optimization techniques are discussed.
The need thus still exists for a flexible throttle plate design that reduces the air rush noise across vehicle models. There needs to be a method to accomplish the noise reduction while not causing a power loss when the throttle plate is fully open. There also needs to be a method of optimizing and customizing the design to reduce the air rush noise in each individual vehicle to accommodate the different manifold and throttle body designs.
SUMMARY OF THE INVENTION
In accordance with the present invention, these and other objects are accomplished by providing an apparatus and a method for reducing the air rush noise in a variety of motor vehicles when the throttle plate is open. This reduction is for throttle plates that are gradually opened, held in a partially-open position or are rapidly opened.
On a vehicle, the throttle plate opens when the engine needs to deliver more power. The air flow over the throttle plate inside the throttle bore can cause increased turbulence and vorticies. Fins added to the throttle plate can prevent the vorticies from being generated and act to straighten the flow, thus mitigating the turbulence in the flow downstream of the plate. The fins delay convergence of the turbulent air to a point further downstream when the energy has been dissipated. This, in turn, mitigates the source of the noise. With the fins attached to one or both sides of the throttle plate, the designer has the ability to tune the acoustical response as well as the restriction imposed by the fins minimizing the effect on the engine's power output. The fins may be of constant width and spaced consistently across the throttle plate, or the spacing and width may vary.
The present invention uses fins in one or more orientations on the throttle plate to manage the flow of the air through the throttle bore to the manifold to mitigate the source of the noise. The throttle bore may be cylindrical, oval, elliptical, or a similar shape. A variety of computational fluid dynamics and other computer aided engineering methods, along with bench testing, can be used to simulate the flow of the air through the specific throttle body/manifold design to simulate the air flow and optimize the design of the fins of the throttle plate. This optimization depends upon many factors including the duct section geometry of the induction system, the airflow rate, and customer design specifications for pressure drop and radiated sound levels. The fins can be fabricated of various materials such as composite plastics or die cast aluminum. The fins can be attached to the throttle plate by various methods such as a mechanical joint, adhesive or welding. The fins could also be integrated into the plate as a one-piece design.
Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which the present invention relates from the subsequent description of the preferred embodiments and the appended claims, taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the throttle body and manifold system showing the present invention;
FIG. 2 is a sectional view cut through the throttle bore of FIG. 1
FIG. 3 is an end view of the throttle plate of the present invention within the throttle body in the closed position;
FIG. 4 is an end view of the throttle plate of the present invention within the throttle body in the open position;
FIG. 4A is a cross-sectional view of the throttle plate of the present invention within the throttle body in the open position;
FIG. 5 is a perspective view of the throttle plate according to another embodiment of the present invention;
FIG. 6 is a side view of the embodiment shown in FIG. 5; and
FIG. 7 is a perspective view of an embodiment of the throttle plate of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now in detail to the drawings, shown in FIG. 1, the throttle body 4 and intake manifold 11 portion of the air intake system of an electronically fuel injected vehicle is shown. The manifold 11 is the portion of the air intake system that interacts with the fuel components. Air enters the plenum portion 6 of the manifold 11 from the throttle body 4 . The plenum portion 6 of the manifold 11 evens out the pulses in the air to help fuel economy and emissions before the air enters the inlet tracks 7 . The air from the inlet tracks 7 mixes with the fuel spray from the fuel injectors mounted on a fuel rail at the exit of the inlet tracks 7 (not shown). Thereafter, the fuel-air mixture is combusted in the combustion chamber of the engine.
The manifold 11 is attached to the throttle body 4 on the plenum 6 side of the manifold 11 at the manifold inlet 13 . The throttle body 4 mounts via a mounting flange 15 to a mounting surface 14 of the manifold inlet 13 . Fasteners, such as bolts, screws or other means, fastened through manifold attachment holes 17 and 19 , respectively formed in the mounting surface 14 and mounting flange 15 , secure the throttle body 4 to the manifold inlet 13 of the manifold 11 .
The throttle body 4 determines how much air will flow into the plenum 6 and therefore the engine. A throttle plate 2 fits snugly inside a throttle bore 28 defined within a cylindrical ring 21 of the throttle body 4 . The throttle plate 2 is attached to a throttle shaft 12 by fasteners 18 , such as bolts, screws and other means. Rotation of the shaft 12 causes the throttle plate 2 to open and close to regulate the air stream. When the driver depresses the accelerator pedal of the automobile, the throttle shaft 12 is rotated, thus opening the throttle plate 2 and allowing air to flow into the manifold 11 . The air flows through the throttle bore 28 into the manifold inlet 13 in flow direction 20 .
As seen in FIG. 2, attachment of the throttle plate 2 inside of the cylindrical ring 21 , to the throttle body 4 is shown in a sectional view as seen from the manifold 11 attachment side thereof. The throttle bore 28 has two rod holes 30 extending through its sides. The rod holes 30 extend along a common axis 31 and the throttle rod 12 fits through rod holes 30 in the throttle bore 28 . Attached to the throttle rod 12 , the throttle plate 2 fit snugly inside throttle bore 28 to substantially block air flow when the throttle plate 2 is in the closed position. As shown in FIG. 2, the throttle plate 2 is partially open.
The throttle plate 2 may be attached to the throttle rod 12 by screws or bolts 18 extending through mounting rings 25 formed within the throttle rod 12 and into the throttle plate 2 . Formed on or mounted to the throttle plate 2 are fins 8 . Preferably, the fins 8 are on the trailing edge of the throttle plate 2 . As such, when the throttle rod 12 is turned and the throttle plate 2 is opened, the fins 8 operate to mitigate the noise by straightening the air flow in direction 20 .
Referring now to FIG. 3, an end view from the mounting flange 15 of the throttle body 4 is shown. The throttle plate 2 in this view is in the closed position inside the throttle bore 28 and air flow is blocked by the snug fit between the throttle plate 2 and the throttle bore 28 . The fins 8 can be seen facing the mounting flange 15 of the throttle body 4 . When the throttle plate 2 is in this closed position, the fins 8 have no effect on the air intake system.
FIG. 4 is a view from the mounting flange 15 of the throttle body 4 , similar to that seen in FIG. 3 . In this view, the throttle rod 12 has been rotated almost to the open position inside the throttle bore 28 . Rotated as such, the fins 8 move away from an orientation facing the mounting flange 15 towards an angle perpendicular or 90° relative to the closed position (wide open throttle).
Referring now to FIG. 4A, the partially open throttle plate 2 from FIG. 4 is shown in a cross-sectional view. The throttle rod 12 is rotated to open the throttle plate 2 . Air flows in air direction 20 through the throttle bore 28 . The fins 8 manage the air flow through the throttle bore 28 to reduce the air rush noise generated by the air flow over the throttle plate 2 which may be heard in the vehicle.
When the throttle plate 2 is opened, as the air travels in air flow direction 20 , it travels through the fins 8 , which are aligned in the air flow direction 20 path. With the throttle plate 2 open, the fins 8 overhang the throttle plate 2 by overhang distance 26 or height. The intrusion of fins 8 by fin overhang distance 26 modifies the air flow by preventing the vortices from being produced from turbulent flow to laminar flow, quieting the air rush noise of the air flow through the throttle bore 28 into manifold 6 .
Referring now to FIG. 5, a perspective view of one embodiment of the fins 8 of the throttle plate 2 is shown. The fins 8 themselves are formed on a separate fin attachment plate 50 . The fin attachment plate 50 is fastened, using an adhesive or a mechanical fastener, onto the rear side of the throttle plate 2 and on the lower side which forms the leading edge side 51 .
After attachment, the fins 8 progress from approximately the center of the throttle plate 2 and rise from there until reaching the end of the throttle plate 2 , a fin tip height 22 at a fin angle 24 , calculated by using the fin start location 32 and measuring angle between a ray along the fin length 36 and a ray toward the fin tip height 22 . Because of the generally round shape of the throttle plate 2 , the fin length 36 will generally be different for each fin 8 . FIG. 6 is an opposing view of the fin attachment plate 50 to that of FIG. 5 . The fins 8 are seen as being equally spaced 10 between each fin 8 . The fin width 24 is shown to be consistent throughout the fin attachment 50 .
Seen in FIG. 7 is a perspective view of a further embodiment of the present invention. In this embodiment, the fins 8 are manufactured as a unitary part of the throttle plate 2 . The throttle plate 2 with the unitary fins 8 can be a one-piece die casting or made by another manufacturing method. There is no separate fin attachment piece with this embodiment.
In this latter embodiment, the fins 8 start at fin start height 34 , generally along the diameter of the throttle plate 2 . The fins 8 then rise diagonally towards the outer edge of the throttle plate 2 to fin edge height 22 . The fins 8 are again equally spaced with fin spacing 10 . The throttle plate attachment holes 25 are shown near the center of the throttle plate 2 . Formed in this manner, the fins 8 extend completely across the opening created during rotation of the throttle plate 2 , regardless of the open angle of the throttle plate 2 .
While the above description constitutes the preferred embodiments of the present invention, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope and fair meaning of the accompanying claims. | A throttle body for use in the air intake system of a motor vehicle comprising a throttle body defining a throttle bore. The throttle plate is rotatably mounted within the throttle bore, having an outside diameter smaller than an inside diameter of the throttle bore. A plurality of fins, located on the throttle plate, extend from the throttle plate in a direction generally perpendicular to a plane defined by said throttle plate. The fins are optimized in number, thickness, spacing, length, shape, and angle to reduce air-rush noise without impacting engine performance. | 5 |
BACKGROUND
The present invention relates to a cartridge valve for installation in a manifold having a receiving cavity.
Cartridge valves are widely used for proportionately and/or precisely controlling fluid flow or pressure through passages of a hydraulic circuit. In its simplest form, a cartridge valve is used in a receiving cavity of a manifold to regulate the flow of fluid from an inlet port to an outlet port communicating with the receiving cavity. Such cartridge valves are used to controllably operate a fluid circuit and to precisely set and maintain a desired flow through the passage.
Prior art cartridge valves encounter a problem because the design of the valves require precise forming of the receiving cavity in the manifold. If the receiving cavity is not precisely formed in accordance with the required tolerances of the prior art cartridge valve a cage portion of the valve tends to bind or cant against the receiving cavity walls. When the valve binds, a spool portion retained in the cage portion does not freely operate. When the spool does not freely operate, the circuit does not perform as originally designed and additional steps must be taken to determine why the circuit is not operated.
Often times, the cartridge valve is removed and assumed to be defective whereupon a different cartridge valve is installed in the receiving cavity. After a number of attempts with alternate cartridge valves, the mechanic diagnosing the problem may determine that the receiving cavity is the problematic area. The receiving cavity may have to be reworked in order to accommodate the cartridge valve. It should be noted, however, that reworking a receiving cavity may also create problems in that the cavity may become oversized and thereby not providing proper seating and sealing of the cartridge valve installed therein.
Clearly, the problems inherent in prior art cartridge valves require substantial time, effort, and cost. These problems may be escerbated when a valve, which is properly working, fails to operate due to a change in operating conditions. Cartridge valves are used in an environment which is prone to thermal expansion and contraction. Additionally, particulate matter carried in the fluid flow may build up in the valve and foul its operation. With regard to thermal variations, temperature increases may cause the manifold material to expand thereby changing the tolerance of what was previously an acceptable valve. Cooling of the manifold material may provide a similar tolerance variation problem. When the valve tolerances change as a result of thermal expansion or contraction, the valve may bind or leak.
Another problem with prior art cartridge valves occurs as a result of a sampling valve formed in the spool becoming clogged with particulate matter which may be carried in the fluid flow. Since the manifolds are often constructed of metallic materials, particles may be left in the passages and cavities from the original casting and/or machining operations of the manifold. Such particles are carried in the fluid flow once the system is charged. Additionally, particles remaining from the original manufacturing process of the manifold may cause additional wear and thus produce additional particulate matter. When particulate matter is delivered to the spool of a cartridge valve, the sampling orifice may become clogged with such particulate matter. Cleaning of the spool requires extraction of the cartridge valve from the receiving cavity. Removal of the cartridge valve involves depressurizing and draining at least the specific lines associated with the receiving cavity. The removal and cleaning operations require substantial time, effort, cost as well as downtime and the associated downtime costs.
Yet an additional problem found in prior art cartridge valve is that the handle or knob assemblies used to operate and adjust the valves are prone to separation from the cartridge valve. Prior art knob assemblies are attached to the cartridge valve by means of a threaded fastener extending through an adjusting screw portion of the cartridge valve. If the fluid pressure on the adjusting screw is great enough, substantial force may have to be applied through the screw to break open the valve. However, if the force required to brake the valve open is greater than the strength of the material in the screw, or the threaded connection, the fastener may torque off or the threads between the fastener and the adjusting screw may be stripped. Additionally, if the adjusting screw is operated into a maximum limit of the adjusting range, continued application of force to the knob assembly may result in the similar damage. If a knob assembly is damaged, replacement or repair of the knob assembly and associated cartridge valve may require substantial time, effort, cost and associated downtime and cost.
The problems associated with damaged knob assemblies are further escerbated when the failure of the knob assembly causes damage to the control valve. Damage to the control valve may result while boring out a stripped threaded fastener and forming new threads therein. If the adjusting screw is overdrilled during the boring operation, the valve may leak and become irreparably damaged. The additional boring of the adjusting screw also may reduce the strength of the adjusting screw thereby creating a potential fatigue point in the adjusting screw itself. The fatigue point may be the place where the knob assembly fails the next time it is overtorqued.
As it can be seen, there are numerous problems with prior art cartridge valves and knob assemblies. The invention as shown and described herein satisfies the requirements for overcoming the above-described problems.
OBJECTS AND SUMMARY
An object satisfied by the present invention is a cartridge valve which prevents a spool in a cage portion of the valve from binding and thereby providing improved performance.
Another object satisfied by the present invention is a cartridge valve which includes a floating cage which is less susceptible to problems caused by incorrect tolerances in the manifold receiving cavity in which the cartridge valve is installed.
Yet another object satisfied by the present invention is a self-cleaning, non-clogging spool sampling orifice which facilitates greater reliability of operation.
Yet a further object satisfied by the present invention is a knob assembly for use with a cartridge valve which resists damage to the valve as a result of rotating the knob assembly to control the cartridge valve.
Briefly, and in accordance with the foregoing, the present invention envisions a cartridge valve for installation in a manifold having a receiving cavity which includes an inlet port and an outlet port. The cartridge valve includes a cavity adaptor for engaging the cartridge valve with the receiving cavity in the manifold, a cage assembly which includes a floating cage within a portion of the cavity adaptor, and a control device which controls the flow through or pressure the cartridge valve. The cavity adaptor has walls defining a primary bore and the cage body has walls defining a second bore. The cavity adaptor and the cage body are sized and dimensioned so that an interior dimension of the cavity adaptor is greater than an exterior dimension of the corresponding portion of the cage body. The dimensional difference between the interior surface of the cavity adaptor and the exterior surface of the cage body defines a radial passage. A knob assembly associated with the cartridge valve includes a split collet which is positively retained on a handle portion. A recess in the cartridge valve receives the split collet. A tapered bushing is mated with the split collet to spread portions of the collet to securely engage the collet in the recess in the cartridge valve.
BRIEF DESCRIPTION OF THE DRAWINGS
The organization and manner of the structure and operation of the invention, together with further objects and advantages thereof, may be understood by reference to the following description taken in connection with the accompanying drawings, wherein like reference numerals identify like elements, and in which:
FIG. 1 is a partial fragmentary, cross sectional, side elevational view of a cartridge valve of the present invention engaged in a receiving cavity of a manifold for controlling the flow from an inlet port to an outlet port;
FIG. 2 is a partial fragmentary, cross sectional, side elevational view of the cartridge valve as shown in FIG. 1 in which the valve has been operated to allow flow from an inlet port to axially displace a spool thereby allowing flow from the inlet port through a transverse passage to an outlet port;
FIG. 3 is an exploded, perspective view of a knob which is engaged with the adjusting screw of the cartridge valve to precisely control the flow or pressure therethrough;
FIG. 4 is a plan view taken along line 4--4 in FIG. 1 showing a bottom portion of a collet and bushing used to retain the knob assembly in a recess on the adjusting screw; and
FIG. 5 is a partial fragmentary, cross sectional, side elevational view taken along line 5--5 in FIG. 1 showing the expanding action of the bushing on the split collet as used in the knob assembly of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
While the invention may be susceptible to embodiment in different forms, there is shown in the drawings, and herein will be described in detail, an embodiment with the understanding that the present description is to be considered an exemplification of the principles of the invention and is not intended to limit the invention to that as illustrated and described herein.
With reference to FIG. 1, a cartridge valve 20 including a knob assembly 22 is shown. The cartridge valve 20 is engaged with a manifold 24 having a valve receiving cavity 26 formed therein. An inlet port 28 and an outlet port 30 communicate with the valve receiving cavity 26. Fluid flow through the manifold 24 follows a path from the inlet port 28 through the cartridge valve 20 retained in the receiving cavity 26 and into the outlet port 30. The cartridge valve 20 allows precise regulation of the flow or pressure from the inlet port 28 to the outlet port 30.
The cartridge valve 20 includes a cavity adaptor 32 which is threadedly engaged with a mouth 34 of the valve receiving cavity 26. Walls 36 of the cavity adaptor 32 define a primary bore 38 having a central axis 40 longitudinally extending therethrough. A biased adjusting assembly or means for resisting opening of the cartridge valve 42 is retained on a generally extending portion 44 of the cavity adaptor 32 which is positioned outside of the manifold 24. An engaging portion 46 is threaded in the mouth 34 of the cavity 26.
A cage assembly 48 is retained in the primary bore 38 and extends into the valve receiving cavity 26. The cage assembly 48 is tiltable and axially shiftable relative to the central axis 40. Included in the cage assembly 48 is a cage body 50 which has an outside dimension 52 which is less than an inside dimension 54 of the primary bore 38. A radial passage 56 is defined by the difference between the dimensions 52,54. The cage assembly 48 further includes a pilot seat 58 having a radially extending, annular flange 60 and a threaded neck 62. A ledge 64 formed in the primary bore 38 cooperatively retains the radial flange 60 abutting the ledge 64. The configuration of the radial flange 60 and the annular ledge 64 limit the movement of the pilot seat 58 through the primary bore 38 towards the cavity 26.
A first end 66 of the cage body 50 is formed with an internal thread 68 for mating with an external thread 70 on the neck 62 of the pilot seat 58. A second, distal end 72 of the cage body 50 is positioned for engagement with a reduced diameter portion 74 of the cavity 26. The walls 76 of the cage body 50 define a secondary bore 78. A transverse passage 80 is shown in cross section extending through the wall 76 generally perpendicular to the central axis 40. A plurality of transverse passages are spaced around the cage body 50 to allow fluid flow therethrough as described hereinbelow. An axially displaceable spool 82 is retained in the secondary bore 78. The spool has a radially extending, annular flange 84 which abuts an annular ledge 86 formed on an inside surface of the cage body 50. The configuration of the flange and ledge 84,86 limits the movement of the spool towards the second end 72 of the cage body 50. A spring 88 is retained between the pilot seat 58 and the spool 82 to normally bias the spool 82 in a position where the flange 84 engages the ledge 86.
The spring 88 biases the spool 82 in a position whereby an outside surface 90 of the spool blocks the transverse passages 80 preventing fluid flow from the inlet port 28 therethrough. The biased adjusting assembly 42 includes a retaining body 92 threadedly engaged with the cavity adaptor 32, a hollow adjusting screw 94 threadedly engaged with the retaining body 92 and a biased flow or pressure control means 96 retained between a cavity 98 of the adjusting screw 94 and the pilot seat 58.
Movement of the cage 76 and pilot seat 58 in the cavity adaptor 32 is permitted by dimensional differences between the two components 76, 58 and the adapter 32. For example, a gap is formed between the rim 97 of the retaining body 92 and the ledge 64 of the cavity adapter 32. The gap is slightly larger than corresponding thickness dimension of the radially extending annular flange 60 of the pilot seat 58. Additionally, as mentioned hereinabove, the dimensional difference between the cage 76 and the cavity adaptor 32 defines a radial passage 56 therebetween. A small gap is defined between the outside edge of the flange 60 of the pilot seat 58 and the inside surface of the cavity adapter 32 in the area of the ledge 64. These dimensional differences allow a degree of axial movement from a position whereby the flange 60 abuts the ledge 64 to a position whereby the flange 60 abuts the rim 97. Further, a degree of angular displacement relative to the central axis 40 is achieved as a result of canting or displacement of the cage 76 as a result of the passage 56 and the gap between the flange 60 and the inside surface of the cavity adapter 32 and cage assembly 48.
The pilot seat 58 includes an entry aperture 100 and a plurality of flow apertures 102 radially spaced away from the entry aperture 100 generally along the flange 60. A flow chamber 104 is defined between the pilot seat 58, retaining body 92 and adjusting screw 94. Fluid may flow from the entry aperture 100, through the flow chamber 104, into the flow apertures 102 which communicate with the radial passage 56.
The flow or pressure control means 96 includes a spring 106, a ball retainer 108 and a sealing sphere 110. A recess 112 is formed in a face of the ball retainer 108 for captively retaining the sealing sphere 110 therein. The spring 106 biases the retainer and sphere into engagement with the entry aperture 100. As shown in FIG. 1, the adjusting screw 94 is threaded downwardly towards the pilot seat 58 thereby compressing the spring 106 to securely retain the sphere 110 in engagement with the entry aperture 100.
A sampling orifice 114 is formed in the tip of spool 82 and communicates with the inlet port 28 allowing fluid to pass therethrough into the secondary bore 78 and the entry aperture 100. As shown in FIG. 1, the adjustment screw 94 compresses the spring 106 to create a biasing force which is greater than the flow pressure through the sampling orifice 114 against the sphere 110. In this position, the valve 20 is "closed" such that fluid cannot flow from the inlet port 28 through the valve 20 to the outlet port 30.
Before proceeding further, it should be noted that a number of gaskets or seals are provided between the surfaces of the cartridge valve 20 and the manifold 24. For example, nonmovable gaskets 116 are positioned between the retaining body 92 and the cavity adaptor 32, the pilot seat 58 and the cage body 50, and the cavity adaptor 32 and the mouth 34 of the cavity 26. These seals 116 are not moved or otherwise displaced during the normal operation of the cartridge valve 20. Rather, the seal 116 is positioned between the abutting components and the abutting components are assembled thereby compressing the gasket to form a seal. Operable seals 118 are provided between the adjusting screw 94 and the retaining body 92 and the cage body 50 and the corresponding reduced diameter surface 74 of the cavity 26. These sealing points are displaced during the operation of the valve 20 and therefor include an o-ring as well as rigid rings.
Turning now to FIG. 2, the adjusting screw 94 has been axially displaced away from the pilot seat 58 thereby reducing the biasing force of the flow control means 96 on the entry aperture 100. The reduced biasing force allows the sphere 110 to be unseated from the entry aperture 100 by fluid flow through the sampling orifice 114. Fluid flows into the chamber 104 and through the flow apertures 102 to the radial passage 56. Fluid then flows from the radial passage 56 into the outlet port 30. The flow of fluid through the entry aperture 100 reduces the fluid pressure in a chamber 119 defined between the spool 82 and the pilot seat 58. The reduced fluid pressure is less than the fluid pressure on a face 120 of the spool 82 thereby displacing the spool 82 along the central axis 40. The adjusting screw 94 is precisely adjusted to control the biasing force by the flow control means 96. This controlled biasing produces controlled axial displacement of the spool 82 to reveal a portion of the transverse passages 80. The controlled exposure of the transverse passages 80 produces controlled flow from the inlet port 28 to the outlet port 30. As shown in FIG. 2, the adjustment screw has been adjusted to a maximum position away from the pilot seat 58 thereby allowing full exposure of the transverse passages 80 and maximum fluid flow therethrough.
An additional feature of the present invention is the non-clogging face 120 of the spool 76. An annular concave groove 121 is formed in the face 120 surrounding a tip 123 through which the sampling orifice 114 is formed. The annular concave groove 121 collects and directs particles away from the sampling orifice 114 to prevent such particles from clogging the orifice.
Turning now to the knob assembly 22 as shown in FIGS. 1 and 3-5, the knob assembly 22 includes a handle portion 122, a split collet 124, a fastener 126 and a frustoconical bushing 128 engaged by the fastener 126 and retained in the collet 124. With reference to FIG. 3, the adjusting screw 94 includes a recess 130 formed in an upper portion thereof. A first end 133 of the collet 124 has a keyed external surface 135 which cooperatively engages a corresponding keyed internal surface or aperture 136 formed in the handle 122. An outside surface 132 of a second end 137 of the collet 124 is shaped to cooperatively engage the inside surface of the recess 130. As shown in the preferred embodiment, the shape of the second end 137 of the collet 124 has a hexagonal shape (See, FIG. 4) which corresponds to the hexagonal shape of the recess 130.
The collet 124 is referred to as being split since walls 144 have axially aligned openings 146 formed therethrough. The outside surface 132 of the collet is formed with generally planar surfaces 148 and the axially aligned opening 146 are positioned generally intermediate these planar surfaces 148. The planar surfaces 148 intersect between neighboring axially aligned openings to define an angular protrusion 150. A series of transverse grooves 152 are formed across the angled protrusions 150. A first wall 154 of the groove 152 is formed at an angle 156 relative to a second wall 158. The transverse grooves 152 effectively form barbs 160 on the angled protrusions 150.
With reference to FIGS. 1, 4 and 5, the frustoconical bushing 128 is employed to drive the angled protrusions 150 of the collet into intimate engagement with a corresponding surfaces of the recess 130. The barbs 160 on the angled protrusions 150 further facilitate secure engagement of the collet 124 in the recess 130.
As shown in the figures, the fastener 126 extends through the keyed aperture 136 of the handle 122 and extends through a bore 138 formed in the collet 124. External threads 161 engage cooperatively formed internal threads 163 formed in the frustoconical bushing 128. Tapered walls 162 of the bushing 128 are urged upwardly through a mouth 164 of the bore 138 by the engagement of the threads 161,163. As the bushing 128 is urged upwardly into the bore 138, the walls 144 of the collet 124 are driven outwardly into engagement with the corresponding walls 139 of the recess 130. A lock washer 166 and an enlarged washer 168 are provided between the fastener 126 and the handle 122 to provide further securing of the fastener 126 once engaged with the bushing 128.
Additionally, a locking ring 170 is threadedly engaged with external threads 172 of the adjusting screw 94 to securely retain a selected adjustment of the adjusting screw 94. A cap 174 includes a rim 176 having spaced apart detents 178 which engage a corresponding internal surface 180 of the handle 122. The cap 174 is secured on the handle 122 to prevent access to the fastener 126 thereby preventing removal of the knob assembly 22 from the cartridge valve 20.
It should be noted that the keyed engagement of the handle 122 with the collet 124 and the expanded friction fit of the collet 124 engaged with the recess 130 prevents damage or failure of the knob assembly 22. Additionally, even if the knob assembly 22 were somehow damaged, replacement is uncomplicated. If, for some reason, the collet 124 were to fail, the fastener 126 is removed thereby relieving the expanding forces produced by the bushing 128 on the collet 124. With the expanding forces removed, the collet and bushing can be removed from the recess 130 whereupon a new knob assembly 22 may be attached. The preferred embodiment of the knob assembly 22 eliminates the risk of stripping a threaded recess on the cartridge valve 20 as in the prior art. There is very little if any risk of the hexagonal portion of the collet 124 stripping or rotating in the recess 130. Additionally, if the fastener cannot be removed from a damaged knob assembly, a head 182 of the fastener is all that needs to be removed. In this situation, once the head 182 is removed, the handle 122 can be removed from the collet and the collet disengaged from the bushing. This is possible since the collet 124 is not threadedly engaged with the fastener 126. The knob assembly of the present invention eliminates damage to the cartridge valve 20 due to failure of the knob assembly 22 as well as potential damage by drilling or tapping a damaged knob assembly 22.
In use, the cartridge valve 20 and the knob assembly 22 of the present invention provide advantages over the prior art. The cartridge valve 20 is inserted and attached to the valve receiving cavity 26 of the manifold 24. The cavity adaptor 32 is threaded to engage the mouth 34 of the receiving cavity 26. The cage body 50 of the cage assembly 48 extends from the cavity adaptor 32 and into the receiving cavity 26. Inlet and outlet ports 28,30 communicate with the receiving cavity 26 and the transverse passages 80 of the cage body 50. The spool 76 is normally biased into a position inside the cage body 50 to block the transverse passages 50. In this position, fluid flow through the inlet port 28 cannot pass through the valve to the outlet port 30.
In the closed position as described above, the adjusting screw 94 is adjusted axially into the retaining body 92 to increase the biasing force of the spring 106 on the ball retainer and sealing sphere 108,110 against the entry aperture 100. This adjustment of the adjustment screw 94 maintains the fluid pressure in the chamber 119 between the pilot seat 58 and the spool 82. Once the adjusting screw is axially adjusted away from the manifold, the biasing force of the spring 106 is reduced thereby allowing fluid flow through the sampling orifice 114 to flow through the entry aperture 100 and into the flow chamber 104.
Fluid entering the flow chamber passes through the flow apertures 102 and the radial passage 56. This initial flow primes the outlet port 30 prior to increased flow through the transverse passages. The adjusting screw 94 can be precisely positioned to provide a desired biasing force which allows controlled movement of the spool 82 in the cage body 50. As the biasing force is reduced, the spool moves axially along the central axis 40 to reveal at least a portion of the transverse passages 80.
An important feature of the present invention is the floating cage assembly 48. The cage assembly 48 is movable or "floats" inside the primary bore 38 of the cavity adaptor 32. A degree of movement of float is permitted between the cage body 50 and the cavity adaptor 32 since the cage body is not threadedly engaged or retained in the cavity adaptor 32. Rather, the cage body 50 is engaged with the pilot seat 58 which is allowed a degree of axial movement between the rim 97 of the retainer body 92 and the ledge 64.
The floating cage assembly 48 feature is very important in that the cartridge valve 20 is very forgiving of inaccurate tolerances in the valve receiving cavity. In this regard, the degree of movement allows the cage body to be angled or canted slightly off the central axis without binding the spool 82 retained therein. In contrast, in prior art devices, if the cage body 50 is canted off of the central axis, the canting tends to bind the spool and prevent movement of the spool within the cage body. Further, the radial passage formed between the outside surface of the cage body and the inside surface of the cavity adaptor allows movement of the cage body in virtually any radial direction.
The knob assembly 22 of the present invention is important to provide precise control and to prevent damage to the cartridge valve 20 as described hereinabove. The knob assembly 22 is easily replaced in the unusual event that the assembly is damaged.
While a preferred embodiment of the present invention is shown and described, it is envisioned that those skilled in the art may devise various modifications of the present invention without departing from the spirit and scope of the appended claims. The invention is not intended to be limited by the foregoing disclosure. | A cartridge valve for installation in a manifold having a receiving cavity which includes an inlet port and an outlet port. The cartridge valve includes a cavity adaptor for engaging the cartridge valve with the receiving cavity in the manifold, a cage assembly which includes a floating cage body within a portion of the cavity adaptor, and a control device which controls the flow through the cartridge valve. The cavity adaptor has walls defining a primary bore and the cage body has walls defining a second bore. The cavity adaptor and the cage body are sized and dimensioned so that an interior dimension of the cavity adaptor is greater than an exterior dimension of the corresponding portion of the cage body. The dimensional difference between the interior surface of the cavity adaptor and the exterior surface of the cage body defines a radial passage. A knob assembly associated with the cartridge valve includes a split collet which is positively retained on a handle portion. A recess in the cartridge valve receives the split collet. A tapered bushing is mated with the split collet to spread portions of the collet to securely engage the collet in the recess in the cartridge valve. | 5 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a non-provisional application which claims benefit under 35 USC §119(e) to U.S. Provisional Application Ser. No. 61/405,497 filed Oct. 21, 2010, entitled “Ice Worthy Jack-Up Drilling Unit,” and is a continuation-in-part application which claims benefit under 35 USC §120 to U.S. application Ser. No. 13/277,791 filed Oct. 20, 2011, entitled “Ice Worthy Jack-Up Drilling Unit” both of which are incorporated herein in their entirety.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] None.
FIELD OF THE INVENTION
[0003] This invention relates to mobile offshore drilling units, often called “jack-up” drilling units or rigs that are used in shallow water, typically less than 400 feet, for drilling for hydrocarbons.
BACKGROUND OF THE INVENTION
[0004] In the never-ending search for hydrocarbons, many oil and gas reservoirs have been discovered over the last one hundred and fifty years. Many technologies have been developed to find new reservoirs and resources and most areas of the world have been scoured looking for new discoveries. Few expect that any large, undiscovered resources remain to be found near populated areas and in places that would be easily accessed. Instead, new large reserves are being found in more challenging and difficult to reach areas.
[0005] One promising area is in the offshore Arctic. However, the Arctic is remote and cold where ice on the water creates considerable challenges for prospecting for and producing hydrocarbons. Over the years, it has generally been regarded that six unprofitable wells must be drilled for every profitable well. If this is actually true, one must hope that the unprofitable wells will not be expensive to drill. However, in the Arctic, little, if anything, is inexpensive.
[0006] Currently, in the shallow waters of cold weather places like the Arctic, a jack-up or mobile offshore drilling unit (MODU) can be used for about 45-90 days in the short, open-water summer season. Predicting when the drilling season starts and ends is a game of chance and many efforts are undertaken to determine when the jack-up may be safely towed to the drilling location and drilling may be started. Once started, there is considerable urgency to complete the well to avoid having to disconnect and retreat in the event of ice incursion before the well is complete. Even during the few weeks of open water, ice floes present a significant hazard to jack-up drilling rigs where the drilling rig is on location and legs of the jack-up drilling rig are exposed and quite vulnerable to damage.
[0007] Jack-up rigs are mobile, self-elevating, offshore drilling and workover platforms equipped with legs that are arranged to be lowered to the sea floor and then to lift the hull out of the water. Jack-up rigs typically include the drilling and/or workover equipment, leg jacking system, crew quarters, loading and unloading facilities, storage areas for bulk and liquid materials, helicopter landing deck and other related facilities and equipment.
[0008] A jack-up rig is designed to be towed to the drilling site and jacked-up out of the water so that the wave action of the sea only impacts the legs which have a fairly small cross section and thus allows the wave action to pass by without imparting significant movement to the jack-up rig. However, the legs of a jack-up provide little defense against ice floe collisions and an ice floe of any notable size is capable of causing structural damage to one or more legs and/or pushing the rig off location. If this type of event were to happen before the drilling operations were suspended and suitable secure and abandon had been completed, a hydrocarbon leak would possibly occur. Even a small risk of such a leak is completely unacceptable in the oil and gas industry, to the regulators and to the public.
[0009] Thus, once it is determined that a potentially profitable well has been drilled during this short season, a very large, gravity based production system, or similar structure may be brought in and set on the sea floor for the long process of drilling and producing the hydrocarbons. These gravity based structures are very large and very expensive, but are built to withstand the ice forces year around.
BRIEF SUMMARY OF THE DISCLOSURE
[0010] The invention more particularly relates to an ice worthy jack up rig for drilling for hydrocarbons in potential ice conditions in offshore areas including a flotation hull having a relatively flat deck at the upper portion thereof. The flotation hull further includes an ice bending shape along the lower portion thereof and extending around the periphery of the hull where the ice bending shape extends from an area of the hull near the level of the deck and extends downwardly near the bottom of the hull along with an ice deflecting portion extending around the perimeter of the bottom of the hull to direct ice around the hull and not under the hull. The rig includes at least three legs that are positioned within the perimeter of the bottom of the hull wherein the legs are arranged to be lifted up off the seafloor so that the rig may be towed through shallow water and also extend to the sea floor and extend further to lift the hull partially or fully out of the water. A jack up device is associated with each leg to both lift the leg from the sea bottom so that the ice worthy jack up rig may float by the buoyancy of the hull and push the legs down to the seafloor and push the hull partially up and out of the water when ice floes threaten the rig and fully out of the water when ice is not present. The rig further includes a moon pool in the deck and positioned within the perimeter of the bottom of the hull and inside the ice deflecting portion.
[0011] The invention further relates to a method for drilling wells in ice prone waters. The method includes providing a flotation hull having a relatively flat deck at the upper portion thereof and an ice bending shape along the lower portion thereof where the ice bending shape extends from an area of the hull near the level of the deck and extends downwardly near the bottom of the hull and an ice deflecting portion extending around the perimeter of the bottom of the hull to direct ice around the hull and not under the hull. At least three legs are positioned within the perimeter of the bottom of the hull. Each leg is jacked down in a manner that feet on the bottom of the legs engages the sea floor and lifts the hull up and fully out of the water when ice is not threatening the rig while the rig is drilling a well on a drill site. The hull is further lowered into the water into an ice defensive configuration so that the ice bending shape extends above and below the sea surface to bend ice that comes against the rig to cause the ice to submerge under the water and endure bending forces that break the ice where the ice flows past the rig. The method includes drilling through a moon pool in the deck that is positioned within the perimeter of the bottom of the hull and inside the ice deflecting portion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] A more complete understanding of the present invention and benefits thereof may be acquired by referring to the follow description taken in conjunction with the accompanying drawings in which:
[0013] FIG. 1 is an elevation view of the present invention where the drilling rig is floating in the water and available to be towed to a well drilling site;
[0014] FIG. 2 is an elevation view of the present invention where the drilling rig is jacked up out of the water;
[0015] FIG. 3 is an elevation view of the first embodiment of the present invention where the drilling rig is partially lowered into the ice/water interface, but still supported by its legs, in a defensive configuration for drilling during potential ice conditions;
[0016] FIG. 4 is an enlarged fragmentary elevation view showing one end of the first embodiment of the present invention in the FIG. 3 configuration with ice moving against the rig;
[0017] FIG. 5A is an elevation view showing the derrick is in a cantilevered position drilling over the side of the deck in the conventional manner of a conventional jack-up drilling rig;
[0018] FIG. 5B is a partially fragmentary elevation view where a moon pool is shown included in the hull so that the drill string benefits from the ice protection of the ice worthy hull configuration;
[0019] FIG. 6A is a top view of the first embodiment of the present invention where a cantilever derrick is positioned to drill through the moon pool; and
[0020] FIG. 6B is a top view of the first embodiment of the present invention where a cantilever derrick is positioned to drill over the edge of the deck.
DETAILED DESCRIPTION
[0021] Turning now to the detailed description of the preferred arrangement or arrangements of the present invention, it should be understood that the inventive features and concepts may be manifested in other arrangements and that the scope of the invention is not limited to the embodiments described or illustrated. The scope of the invention is intended only to be limited by the scope of the claims that follow.
[0022] As shown in FIG. 1 , an ice worthy jack-up rig is generally indicated by the arrow 10 . In FIG. 1 , jack-up rig 10 is shown with its hull 20 floating in the sea and legs 25 in a lifted arrangement where much of the length of the legs 25 extend above the deck 21 of the hull 20 . On the deck 21 is derrick 30 which is used to drill wells. In the configuration shown in FIG. 1 , the jack-up rig 10 may be towed from one prospect field to another and to and from shore bases for maintenance and other shore service.
[0023] When the jack-up rig 10 is towed to a drilling site in generally shallow water, the legs 25 are lowered through the openings 27 in hull 20 until the feet 26 at the bottom ends of the legs 25 engage the seafloor 15 as shown in FIG. 2 . In a preferred embodiment, the feet 26 are connected to spud cans 28 to secure the rig 10 to the seafloor. Once the feet 26 engage the seafloor 15 , jacking rigs within openings 27 push the legs 25 down and therefore, the hull 20 is lifted out of the water. With the hull 20 fully jacked-up and out of the water, any wave action and heavy seas more easily break past the legs 25 as compared to the effect of waves against a large buoyant object like the hull 20 .
[0024] When ice begins to form on the sea surface 12 , the risk of an ice floe contacting and damaging the legs 25 or simply bulldozing the jack-up rig 10 off the drilling site becomes a significant concern for conventional jack-up rigs and such rigs are typically removed from drill sites by the end of the open water season. The ice-worthy jack-up drilling rig 10 of the present invention is designed to resist ice floes by assuming an ice defensive, hull-in-water configuration as shown in FIG. 3 . In FIG. 3 , ice tends to dampen waves and rough seas, so the sea surface 12 appears less threatening, however, the hazards of the marine environment have only altered, and not lessened.
[0025] When the ice-worthy jack-up rig 10 assumes its ice defensive, hull-in-water configuration, the hull 20 is lowered into the water to contact same, but not to the extent that the hull 20 would begin to float. A significant portion of the weight of the rig 10 preferably remains on the legs 25 to hold the position of the rig 10 on the drill site against any pressure an ice flow might bring. The rig 10 is lowered so that inwardly sloped, ice-bending surface 41 bridges the sea surface 12 or ice/water interface to engage any floating ice that may come upon the rig 10 .
[0026] The sloped ice-bending surface 41 runs from shoulder 42 , which is at the edge of the deck 26 , down to neckline 44 . Ice deflector 45 extends downward from neckline 44 . Thus, when an ice floe, such as shown at 51 comes to the rig 10 , the ice-bending surface 41 causes the leading edge of the ice floe 51 to submerge under the sea surface 12 and apply a significant bending force that breaks large ice floes into smaller, less damaging, less hazardous bits of ice. For example, it is conceivable that an ice floe being hundreds of feet and maybe miles across could come toward the rig 10 . If the ice floe is broken into bits that are less than twenty feet in the longest dimension, such bits are able to pass around the rig 10 with much less concern.
[0027] In FIG. 4A , the cantilevered derrick 30 is positioned to drill over the side of the deck 20 in accordance with conventional jack-up drilling rigs. Rig 10 , of course includes the ice worthy hull 20 , so the system illustrated in FIG. 4A is not entirely conventional.
[0028] It should be noted that conventional jack-up drilling rigs do not have moon pools. As shown in FIG. 4B , the cantilevered derrick is provided with a moon pool 32 so the riser 35 and the drill string 36 may be positioned within the perimeter of the ice deflector 45 and enjoy the ice protection that the ice-engaging surface 41 and ice deflector 45 provide.
[0029] Ice has substantial compressive strength being in the range of 4 to 12 MPa, but is much weaker against bending with typical flexure strength in the range of 0.3 to 0.5 MPa. As shown, the force of the ice floe 51 moving along the sea surface 12 causes the leading edge to slide under the sea surface 12 and caused section 52 to break off. With the ice floe 51 broken into smaller floes, such as section 52 and bit 53 , the smaller sections tend to float past and around the rig 10 without applying the impacts or forces of a large floe. It is preferred that ice not be forced under the flat of bottom of the hull 20 and the ice deflector 45 turns ice to flow around the side of the hull 20 . If the ice is really thick, the ice deflector 45 is arranged to extend downwardly at a steeper angle than ice-bending surface 41 and will increase the bending forces on the ice floe. At the ice deflector 45 , an ice deflector is positioned to extend down from the flat of bottom of the hull 20 . In an optional arrangement, the turn of the bilge is the flat of bottom at the bottom end of the ice deflector 45 .
[0030] To additionally resist the forces that an ice floe may impose on the rig 10 , the feet 26 of the legs may be arranged to connect to cans 28 set in the sea floor so that when an ice floe comes against the ice-bending surface 41 , the legs 25 actually hold the hull 20 down and force the bending of the ice floe and resist the lifting force of the ice floe which, in an extreme case, may lift the near side of the rig 10 and push the rig over on its side by using the feet 26 on the opposite side of the rig 10 as the fulcrum or pivot. The cans in the sea floor are known for other applications and the feet 26 would include appropriate connections to attach and release from the cans, as desired.
[0031] It should probably be noted that shifting from a conventional open water drilling configuration as shown in FIG. 2 to a hull-in-water, ice defensive configuration shown in FIG. 3 may require considerable planning and accommodation depending on what aspect of drilling is ongoing at the time. While some equipment can accommodate shifting of the height of the deck 21 , other equipment may require disconnections or reconfiguration to adapt to a new height off the sea floor 15 .
[0032] The ice-worthy jack-up drill rig 10 is designed to operate like a conventional jack-up rig in open water, but is also designed to settle to the water in an ice defensive position and then re-acquire the conventional stance or configuration when wave action becomes a concern. It is the shape of the hull 20 (as well as its strength) that provides ice bending and breaking capabilities.
[0033] Referring to FIGS. 5A and 5B , the hull (as viewed from above) may have a circular or oval configuration so as to present a shape that is conducive to steering the broken bits and sections of ice around the periphery of the rig 10 regardless of the direction of origin or path of travel. The ice tends to flow with the wind and sea currents, which tend not to be co-linear, or some path reflecting influences of both sea and air.
[0034] The hull 20 preferably has a faceted or multisided shape that provides the advantages of a circular or oval shape, and may be less expensive to construct. The plates that make up the hull would likely be formed of flat sheets and so that the entire structure comprises segments of flat material such as steel would likely require less complication. The ice-breaking surface would preferably extend at least about five meters above the water level, recognizing that water levels shift up and down with tides and storms and perhaps other influences. The height above the water level accommodates ice floes that are quite thick or having ridges that extend well above the sea surface 12 , but since the height of the shoulder 42 is well above the sea surface 12 , the tall ice floes will be forced down as they come into contact with the rig 10 . At the same time, the deck 21 at the top of the hull 20 should be far enough above the water line so that waves are not able to wash across the deck. As such, the deck 25 is preferred to be at least 7 to 8 meters above the sea surface 12 . Conversely, the neckline 42 is preferred to be at least 4 to 8 meters below the sea surface 12 to adequately bend the ice floes to break them up into more harmless bits. Thus, the hull 20 is preferably in the range of 5-16 meters in height from the flat of bottom to the deck 20 , more preferably 8-16 meters or 11-16 meters.
[0035] It should also be noted that the legs 25 and the openings 27 through which they are connected to the hull 20 are within the perimeter of the ice deflector 45 so that the ice floes are less likely to contact the legs while the rig 10 is in its defensive ice condition configuration as shown in FIG. 3 and sometimes called hull-in-water configuration. Moreover, the rig 10 does not have to handle every ice floe threat to significantly add value to oil and gas companies. If rig 10 can extend the drilling season by as little as a month, that would be a fifty percent improvement in some ice prone areas and therefore provide a very real cost saving benefit to the industry.
[0036] Referring to FIGS. 5 a and 5 b , the derrick 30 may be positioned to drill through a moon pool that is within the perimeter of the ice deflector 45 as shown in FIG. 5 a or may be arranged to drill over the side of the deck 21 in a cantilevered fashion as shown in FIG. 5 b.
[0037] In closing, it should be noted that the discussion of any reference is not an admission that it is prior art to the present invention, especially any reference that may have a publication date after the priority date of this application. At the same time, each and every claim below is hereby incorporated into this detailed description or specification as an additional embodiment of the present invention.
[0038] Although the systems and processes described herein have been described in detail, it should be understood that various changes, substitutions, and alterations can be made without departing from the spirit and scope of the invention as defined by the following claims. Those skilled in the art may be able to study the preferred embodiments and identify other ways to practice the invention that are not exactly as described herein. It is the intent of the inventors that variations and equivalents of the invention are within the scope of the claims, while the description, abstract and drawings are not to be used to limit the scope of the invention. The invention is specifically intended to be as broad as the claims below and their equivalents. | The invention relates to an ice worthy jack-up rig that may extend the drilling season in shallow water off shore Arctic or ice prone locations. The inventive rig would work like a conventional jack-up rig while in open water with the hull jacked up out of the water. However, in the event of ice conditions, the legs are held in place by cans embedded in the sea floor to resist lateral movement of the rig and the hull is lowered into the water into an ice defensive configuration. The hull is specifically shaped with an ice-bending surface to bend and break up ice that comes in contact with the hull while in the ice defensive configuration. | 4 |
INTRODUCTION
The present invention relates to a new and unique means and methods for manufacturing contact lenses and more particularly to novel means and methods for casting contact lens blanks in which the lens material is deliberately placed in and cured for adherence to the mold cup in which it is thereafter shipped to a contact lens manufacturer who fabricates the contact lens for the fitter (i.e., ophthalmologist, optometrist or optician).
BACKGROUND OF THE INVENTION
Lenses formed of plastic material for optical applications are well known. A primary use for such lenses is as contact lenses. Generally, contact lenses fall into two major categories one of which is generally characterized as soft hydrophilic contact lenses and the other of which is characterized as rigid gas permeable or hard contact lenses which are generally hydrophobic. In addition to characterization of lenses as "soft" or "hard", contact lenses are often classified as corneal or scleral. A corneal lens is a contact lens whose main bearing portion rests upon the cornea of the eye. Another specialized type of lens is the intraocular lens which is surgically implanted into the eye.
Because of the stringent requirements for first quality contact lenses, extreme precision is required in the making of these lenses. Most plastic contact lens blanks are formed by initially casting an elongated cylindrical rod from a plastic material, such, for example, as cellulose acetate butyrate, silicone acrylate, fluorosilicone acrylate, polymethyl methacrylate, and the like. The cylindrical rod is then transversely cut to form a number of cylindrical lens blanks or buttons. The blanks, having generally opposite planar surfaces, are thereafter furnished to the lens manufacturer where each is machined to prescription and thereafter shipped for fitting to the patient by the fitter. Various machining operations may be accomplished on the blanks. For example, it is common practice to machine the lens blank using a lathe equipped with a diamond bit or other machine tool such as a spherical rotating tool bit. However, the machining operation will impart markings in the surface of the lenses which impairs optical quality and the lens surface must be therefore be very carefully polished to remove the machined surface markings. Underpolishing will leave lathe lines on the optical surface while overpolishing will cause orange peel and a poor quality optical surface.
Another problem in forming lenses from elongated rods is that it is difficult to fabricate such rods having a uniform density. A non-uniform density in the rod creates considerable optical problems such as variations in the refractive index and in the mechanical strength of the manufactured lens.
In an effort to avoid some of the problems of which are inherent in manufacturing plastic contact lens blanks from sections cut from plastic rods, the prior art suggests the formation of contact lenses by pouring the plastic between two parallel spaced glass sheets to form therebetween a plastic sheet having clear surfaces. The plastic sheet is then cut into squares that are slightly larger than the desired diameter of the circular lens blanks. The square pieces are positioned between spindles and are rotated while the periphery is machined by a cutting tool to the desired diameter. Such a procedure is described in U.S. Pat. No. 3,651,192.
Attempts have been also made to cast high quality plastic lenses. For instance, U.S. Pat. No. 3,380,718 suggests the use of a lower concave mold which is filled with allyl diglycol carbonate. A convex mold is lowered by a centering rod mechanism into the material. Heat is applied until the liquid is in the gel stage. Pressure is further increased after the gel stage to reduce shrinkage and other undesirable characteristics. While this process represents an advance in the state of the art, it is still generally limited to special types of lenses, such as bifocal lenses. It is clearly not applicable to contact lenses or to the various plastic materials conventionally used to produce contact lenses. Warpage as well as shrinkage frequently occurs with this method.
Another attempt at improving the methodology of casting contact lens was presented by Neefe in U.S. Pat. No. 4,457,880 in which a lens blank having a finished optical surface is cast from a liquid monomer beneath an optical-surfaced upper mold which is made from a resinous material which adheres to the upper surface of the polymerized lens material. While this approach provided a "handle" for the resulting lens blank while it was being machined, it did nothing to reduce internal stresses on the lens or facilitate shipment and carried with it the further risk of damage and loss when the finished lens blank fell from the "handle" during machining or, conversely, had to be forcibly removed from the mold to which it was stuck. A critical feature of Neefe is that the lens blank be totally non-adherent to the mold cup.
In addition to the prior art deficiencies enumerated above, another serious disadvantage of the prior art arises from the extremely abrasive nature of the lens blanks produced for rigid gas permeable and soft lenses and the seriously adverse effect such blanks have on the life of the diamond tool used to machine the blank into a usable optical lens. Thus, still another unfilled need in the optics industry requires the development of means and methods to substantially reduce the amount of machining required for abrasive lens materials by current practices. It is toward the elimination of these several deficiencies in the prior art that this invention is directed.
BRIEF SUMMARY OF THE INVENTION
The present invention relates to a new and unique method of casting optical lens blanks into a molded cup specially formulated and designed to cause the optical lens material, when cured, to adhere firmly thereto. The method is especially applicable to the production of soft and other daily or extended wear contact lens, intraocular lenses, and other optical lenses. The lens material is cured in the mold cup and in the course thereof firmly adheres to the cup to create an integral blank-mold cup structure, herein referred to as "lens button", which is shipped as a unit to the lens manufacturer where the lens button is appropriately machined to specification and finished to provide a contact lens for subsequent delivery to a filter for installation into a patient. As will appear, the means and methods of the present invention substantially eliminate the major problems confronting the industry and substantially prolong the life of the diamond tools used therewith. Further, as will be later detailed, the method of the present invention produces lenses having substantially less internal stress and a more perfect optical lens surface than has heretofore been obtainable. Further, the method of the present invention produces substantially less rejects and is generally easier to control than the prior art practices thereby enhancing the overall economics of lens production.
Accordingly, a prime object of the present invention is to provide a new and improved method of manufacturing contact lenses which produces an integral mold cup button which, when machined, is capable of substantially reducing the abrasive action on and hence extending the useful life of diamond tool employed to shape and finish the final contact lens.
Another object of the present invention is to provide means and methods of producing contact lenses having substantially less internal stress and enhanced optical surfaces than heretofore obtainable by prior practices.
A further object of the present invention is to provide new and improved means and methods for producing contact lens blanks in a novel shippable mold cup button form which can be readily converted into contact lenses.
Still another object of the present invention is to provide novel and unique means and methods of producing contact lenses having more uniform and consistent dimensional tolerances than has been obtainable by prior art means and methods.
These and still further objects, as shall hereinafter appear, are readily fulfilled by the present invention in a unique and totally unexpected manner as will be readily discerned from the following detailed description of preferred embodiments thereof, especially when read in conjunction with the accompanying drawing in which like parts bear like numbers throughout the several views.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1A is an exploded isometric view of a mold cup and a radius die cover for use in practicing the present invention;
FIG. 1B is an isometric view of a mold assembly embodying the present invention;
FIG. 2 is a cross sectional view taken on line II--II of the mold assembly of FIG. 1B;
FIG. 3 is a cross section taken on line II--II of FIG. 1B of a radius blank-mold cup button unit having a curved interface between the lens blank and the mold cup in accordance with the present invention;
FIG. 4 is a cross section taken on line II--II of FIG. 1B of a radius blank-mold cup button unit having a planar interface between the lens blank and the mold cup in accordance with the present invention;
FIG. 5A is a cross section taken on line II--II of FIG. 2 of another mold cup for use with the present invention and having a double stepped mold cup perimeter for the production of oversize lenses;
FIG. 5B is a plan elevation of the mold cup of FIG. 5A;
FIG. 6A is a cross section taken on line II--II of FIG. 2 of still another mold cup for use with the present invention having a concentrically grooved cavity surface defined therein;
FIG. 6B is a plan elevation of the mold cup of FIG. 6A;
FIG. 7A is a cross section taken on line II--II of FIG. 2 of a modified mold cup for use with the present invention in which axially extending splines are disposed in spaced generally parallel relationship to each other about the inner perimeter of the cavity thereof; and
FIG. 7B is a plan elevation of the mold cup of FIG. 7A.
DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention relates to new and unique means and methods for manufacturing optical lenses by casting techniques. The resulting lenses may have concave or convex curved surfaces or planar surfaces, depending on the optical requirements for the lens. The curved surface, when the lens is finished, forms the anterior or posterior surface of the completed lens and, as will appear, finishing operations are substantially minimized. Furthermore, the present invention is uniquely applicable to the production of contact lenses of the corneal, scleral, bicurve, aspheric, toric, spherical, and lenticular type as well as intraocular lenses, photographic and magnifying lenses.
Referring now to the drawing, and more particularly to FIGS. 1 and 2, the mold assembly of the present invention is identified by the general reference 10 and comprises a mold cup 11 having a lens blank cavity 12 formed therein and mold die 13 which is placed upon cup 11 to cover cup 11 and contain therein a suitable mixture of monomers which was prepared and disposed into cavity 12. While the mixture of monomers polymerizes within the cup 11, an adherent relationship is created between the inner surface 14 of cavity 12 and the polymerizing lens materials which cure to form a lens blank 15. As shown in FIGS. 1 and 2, die 13 has a convex lower surface 16 which when die 13 is separated from the polymerized lens material, that is, lens blank 15, creates a true optical surface 17 on lens blank 15 at the interface between the polymerized material 15 and surface 16 of die 13.
Each lens blank 15 is cast into a special mold cup 11 which will hereinafter be described. Blanks 15 can be formed of any suitable polymerizable lens material such as cellulose acetate butyrate, polymethyl methacrylate, silicone acrylate, fluorosilicone acrylate, and like thermosetting and thermoplastic materials in a mold formed of a material calculated to adhere with the lens material so that when the lens material is fully polymerized, the lens material is firmly secured to the mold cup for subsequent shipment therein and final processing as will be described in full detail hereafter.
As mentioned above, the present invention is broadly applicable to optical lenses of all types including contact lenses of the scleral, bifocal, lenticular, spherical, aspheric, toric, intraocular and corneal types as well as daily and extended wear, and other types of contact lenses. The means and methods hereof permit such lenses to be produced from a broad range of plastic materials, both thermoplastic and thermosetting, ranging from the conventional soft hydrophilic materials such as polymers of 2-hydroxylethylene methacrylate cross-linked with ethylene glycol monomethacrylate or N-vinyl-2-pyrrolidone, to the approved gas permeable or hard materials such as cellulose acetate butyrate, silicone acrylate, fluorosilicone acrylate, polymethylmethacrylate, and the like and mixtures thereof.
In practice, mold cup 11 can be formed of a variety of plastic materials which will adhere to the polymerized lens material 14. Suitable materials for producing mold cup 11 include polyetherimide, polyamide, nylon, polycarbonate, acrylonitrile, polysulfone, PMMA, ethylene terephthalate, polybutylene terephthalate, poly(methyl pentene) as well as blended materials such as acrylate styrene acrylonitrile ("ASA") and polycarbonate ("PC"); acrylonitrile butadiene styrene ("ABS") and nylon; ABS and PC; ABS and polytetrafluoroethylene ("PTFE"); ABS and polysulfone; ABS and polyvinyl chloride ("PVC"); ABS and styrene-methacrylate ("SMA"); ASA and poly(methylmethacrylate) ("PMMA"); ASA and PVC; acetal and PTFE; PVC and acrylic; nylon and ethylene copolymers; nylon and polyethylene ("PE"); nylon and PTFE; PC and PE; PC and polyethylene terephthalate ("PET"); PC and SMA; PC and polyurethane ("TPU"); polybutylene terephthalate ("PBT") and PET; PBT and elastomer; PET and elastomer; PET and polysulfone; polyphenylene ether ("PPE") and polystyrene ("PS"); PPE and polyamide; polyphenylene sulfide ("PPS") and PTFE; PS and elastomer; styrene acrylonitrile ("SAN") and ethylene propylene diene ("EPDM"); and SMA and PS and the like.
In practice, the choice of a particular polymer to be employed as the cup material will depend on the specific monomer mixture selected for the lens material.
The die 13 is formed of a variety of plastic materials which will not adhere to the polymerized lens material such as polypropylene, low and high density polyethylene, Teflon®(polytetrafluorethylene), phenol-formaldehyde polymers, urea formaldehyde, poly chlorotrifluoroethylene and the like.
Both mold cup 11 and die 13 can be fabricated by injection molding with subsequent machining as required.
In a preferred practice of the present invention, mold cup 11 will be formed of one of the above described materials which sets into a relatively soft material which will adhere firmly to the monomers disposed in cavity 12 when they are completely polymerized.
Mold cup 11 can be contoured to form a radial lens blank surface by shaping the lower surface 14 of cavity 12 as a curve, as shown in FIG. 3 or to form a planar lens blank surface by shaping lower surface 14 in cavity 12 as a plane, as shown in FIG. 4.
The method of the present invention is also suitable for producing extra large lenses in a mold cup 11 modified to have a larger cylindrical step in cylindrical portion 18, the step being concentrically superposed with cavity 12 as shown in FIGS. 5A and 5B.
When appropriate, the adherence between the lens blank 15 and mold cup 11 can be mechanically enhanced by defining a plurality of generally concentric grooves 19 in surface 14, as shown in FIGS. 6A and 6B; or by providing a plurality of generally parallel axially extending splines 20 on the inner perimeter 21 of cavity 12, as shown in FIGS. 7A and 7B. In each of these alternative embodiments, grooves 19 and splines 20 serve to enlarge the area of the mating surface occurring between lens blank 15 and mold cup 11 thereby increasing the desired adherence therebetween.
Regardless of which of the several mold cups 11 shown herein and described above is selected for the practice of the present invention, the methodology employed will be basically the same as shall now be described.
First, a mold cup 11 is selected and placed on a level surface. Second, a polymerizable lens material mixture known to provide the properties desired for the lens blank to be formed, will be poured into cavity 12 spreading completely over surface 14 until cavity 12 is properly filled. Die 13 is then placed thereupon with surface 16 engaging the lens material and die 13 resting on the upper annular or die supporting surface 22 of cup 11. Die 13 and mold cup 11 then coact to contain and shape the mixed monomers while they are polymerized into a lens blank. Curing is usually enhanced by heating the mold to a temperature of at least 30° C. but not more than 100° C. for a period of at least 30 minutes but not more than about 24 hours, depending on the monomers chosen for the lens material, the particular initiators admixed therein, and the source of the heat, that is, oven, radiator, ultraviolet lamps or like sources of uniform heat. When the polymer is fully cured, the heat source is removed and die 13 is separated from the lens blank 15 and removed from the mold cup 11 and the resulting integrally formed blank-mold cup unit or button 23 is collected for shipment as needed. Blank-mold cup unit 23 is essentially the same size as the unsheathed lens blanks shipped by the prior art. This provides an even further advantage which will now be described.
The contact lens laboratory will manufacture a contact lens from the blank-mold cup unit 23, shown in FIGS. 3 and 4, by first machining the mold-cup 11 portion, which as indicated is formed of a relatively soft material which can be quickly and easily machined away with little or no wear on the grinding tool, off of button 23 until lens blank 15 is exposed. The lens blank 15 is further fabricated into a usable contact lens by machining away the extraneous portions of the blank 15 to produce a lens which is formed from only the uppermost portion of the lens blank 15.
It is apparent that the various parameters, steps and materials herein described are equally applicable for the manufacture of larger optical lenses such as would be used for cameras, telescopes, and like optical devices by upscaling the means and methods herein described and illustrated.
From the foregoing, it becomes apparent that new and useful procedures have been herein described and illustrated which fulfill all of the aforestated objectives in a remarkably unexpected fashion. It is of course understood that such modifications, alterations and adaptations as may readily occur to any artisan having the ordinary skills to which this invention pertains are intended within the spirit of the present invention which is limited only by the scope of the claims appended hereto. | A mold assembly for casting optical lenses in which an integral lens blank-mold cup unit is created by placing liquid monomers in a cup mold which tightly adheres to polymerized lens material. A radial die is disposed upon the cup mold to contain the monomers during polymerization and to provide the polymerized material with an optical surface. A contact lens is manufactured from the integral lens blank-mold cup unit by machining off the first cup and then extraneous portions of the blank to create a finished lens. | 8 |
CROSS-REFERENCE TO RELATED APPLICATIONS:
[0001] This application is a divisional and claims the benefit of priority of U.S. application Ser. No. 15/047,872, filed 19 Feb. 2016, which claims the benefit of priority to India Application No. 478/DEL/2015, filed 19 Feb. 2015, which applications are incorporated herein by reference and made a part hereof in their entirety, and the benefit of priority of each of which is claimed herein.
FIELD OF INVENTION
[0002] The present invention relates to an antioxidant compound having anti atherosclerotic effect and preparation therof. The present invention relates to the synthesis of TPP+ coupled esculetin (mitochondria-targeted esculetin [Milo-Esc]) followed by the biological evaluation of Mito-Esc for its ability to attenuate Angiotensin-II-induced atherosclerosis in apolipoproteinE knockout (ApoE −/− ) mice along with the endothelial cell age-delaying effects of Mito-Esc.
BACKGROUND AND PRIOR ART REFERENCES
[0003] Atherosclerosis is an excessive inflammatory/proliferative response of the vascular wall to various forms of injury. It has been suggested that, during inflammation, reactive oxygen (ROS) and reactive nitrogen species (RNS)-induced endothelial cell damage represent an important primary event in the process of atherosclerotic lesion formation. The resulting oxidative and nitrosative stress impairs the critical balance of the availability of endothelium-derived nitric oxide in turn promoting the proinflammatory signaling events, ultimately leading to the plaque formation. Atherosclerosis initiating events may be different under different conditions; however endothelial dysfunction is known to be one of the major initiating events. Macrophages also undergo apoptosis inside the endothelium, leading to their phagocytic clearance.
[0004] Increased mitochondrial oxidative damage is a major feature of most age-related human diseases including atherosclerosis and abnormal electron leakage from mitochondria in the respiratory chain in oxidant-stressed cells triggers the formation of ROS in mitochondria leading to altered behavior of the cell/cell death. Previously many studies have linked excess generation of ROS with vascular lesion formation and functional defects. More so, a role for mitochondria-derived ROS in atherogenesis is supported by links between common risk factors for coronary artery disease and increased levels of ROS. Mitochondrial ROS is increased in response to many atherosclerosis inducers including hyperglycemia, triglycerides and ox-LDL. Aortic samples from atherosclerotic patients had greater mitochondrial DNA (mtDNA) damage than nonatherosclerotic aortic samples from age-matched transplant donors (Mitochondrial integrity and function in atherogenesis. Circulation. 2002; 106:544-549). Even though endothelial cells have low mitochondria content, mitochondrial dynamics acts as a prime orchestrator of endothelial homeostasis under normal conditions, an impairment of mitochondrial dynamics because of excess ROS production would cause endothelial dysfunction resulting in diverse vascular diseases. Exposure of endothelial cells to free fatty acids, a common feature seen in patients with metabolic syndrome increases mitochondrial ROS (Palmitate induces C-reactive protein expression in human aortic endothelial cells. Relevance to fatty acid-induced endothelial dysfunction. Metabolism. (2011) 60: 640-648).
[0005] Therefore keeping in view of the involvement of mitochondrial ROS in causing endothelial dysfunction leading to the accentuation of vascular diseases, it would be ideal to counteract mitochondria ROS by targeting ROS scavengers specifically to the site of action. The major drawback of antioxidant therapy in the treatment of mitochondrial diseases has been the inability to enhance antioxidant levels in mitochondria. Recently, there was a breakthrough in mitochondrial targeting of antioxidants (Drug delivery to mitochondria: the key to mitochondrial medicine. Adv Drug Deliv Rev. (2000) 41: 235-50). Antioxidants were covalently coupled to a triphenylphosphonium cation (TPP + ), and these compounds were preferentially taken up by mitochondria (Selective targeting of a redox-active ubiquinone to mitochondria within cells: antioxidant and antiapoptotic properties. J Biol Chem. (2001) 276: 4588-4596). The lipophilic cations easily permeate through the lipid bilayers and subsequently build up several hundred-fold within mitochondria because of a large mitochondrial membrane potential. The uptake of lipophilic cations into the mitochondria increases 10-fold for every 61.5 mV difference in the membrane potential, leading to a 100- to 500-fold accumulation in mitochondria. This strategy not only reduces the concentration of the molecule that is being employed to scavenge ROS, but also reduces the non-specific effects of the molecule if it were to be used at high concentrations to elicit a similar effect.
[0006] Coumarins constitute a group of phenolic compounds widely distributed in natural products (The Pharmacology, Metabolism, Analysis and Applications of Coumarin and Coumarin-Related Compounds. Drug Metab Rev (1990) 22: 503-529), and they have recently attracted much attention because of their wider pharmacological activities. Of these, esculetin (6,7-dihydroxycoumarin) has been shown to be a lipoxygenase inhibitor, and it inhibits the production of leukotrienes and hydroxyeicosatetraenoic acid through the lipoxygenase pathway. More recently, esculetin has been reported to inhibit oxidative damage induced by tert-butyl hydroperoxide in rat liver (Inhibitory effect of esculetin on oxidative damage induced by t-butyl hydroperoxide in rat liver. Arch Toxicol. (2000) 74:467-72). Esculetin protects against cytotoxicity induced by linoleic acid hydroperoxide in HUVEC cells and the radical scavenging ability of esculetin was confirmed by electron para magnetic resonance spectroscopy (Protection of coumarins against linoleic acid hydroperoxide-induced cytotoxicity. Chemico-Biological Interactions 142 (2003) 239-254). However, as coumarins may have poor bioavailability in vivo and do not significantly accumulate within mitochondria, their effectiveness remains limited and because of this, they may have to be employed in higher concentrations to scavenge mitochondrial ROS. In the present patent application, we have used lipophilic cation (TPP+) to target esculetin (FIG. X) to mitochondria and show that mitochondria-targeted esculetin (Mito-Esc) protects oxidant-induced endothelial cell death via nitric oxide and AMPK-dependent pathways at far below concentrations than reported earlier with native esculetin and further we report that Mito-Esc significantly inhibits aortic aneurysm (AA) and atheromatous plaque formation in Angiotensin-II-induced atherosclerotic process in Apolipoprotein E −/− mice model. The following are the prior art literature related to the present invention (WO1996031206; U.S. Pat. No. 6,331,532; WO2008145116; U.S. Pat. No. 4,977,276; U.S. Pat. No. 4,230,624; WO2011115819).
OBJECTIVES OF THE INVENTION
[0007] The main objectives of the invention are as follows
1) To synthesize triphenylphosphonium cation (TPP+) coupled esculetin (Mito-Esc) and compare the accumulation of Mito-Esc versus native esculetin in mitochondria. 2) To study the effect of Mitochondria-targeted esculetin (Mito-Esc) during oxidative stress-induced endothelial cell death. 3) To study the age-delaying effects of Mito-Esc in human aortic endothelial cells (HAEC). 4) To understand the mechanisms of Mito-Esc in regulating oxidative stress-induced endothelial cell death. 5) To investigate the effects of Mito-Esc administration during angiotensin-II (Ang-II)-induced atherosclerosis in Apolipoprotein E knockout (ApoE −/− ) mice model.
SUMMARY OF THE INVENTION
[0013] Accordingly the present invention provides an antioxidant compound having anti atherosclerotic effect and preparation thereof. The invention relates to the synthesis of TPP+ coupled esculetin compound (mitochondria-targeted esculetin (Mito-Esc)) of formula 1, following the scheme as shown in scheme 1
[0000]
X=Carbon chain of 1-30
Z=halogen
R=H/one or more than one substitution alkyl/aryl/heteroatom
[0000]
[0017] The biological evaluation of Mito-Esc for its ability to attenuate Angiotensin-II-induced atherosclerosis in ApoE −/− mice has been done. Mito-Esc selectively accumulated in the mitochondria compared to native (un-tagged) esculetin. Mito-Esc at very low concentrations (2.5 μM) protected human aortic endothelial cells (HAEC) from H 2 O 2 or Angiotensin-II induced oxidative stress and cell death. Mito-Esc by upregulating nitric oxide (NO) levels via increased phosphorylations of both AMPK and eNOS protected HAEC from oxidant-induced cell death. Furthermore, Mito-Esc reduced H 2 O 2 -induced endothelial cell aging. In vivo experimentations in ApoE−/− mice revealed that administration of Mito-Esc in drinking water for 45 days significantly attenuated Ang-II-induced atherosclerosis by reducing plaque and aortic aneurysm incidence. Mito-Esc also significantly inhibited Ang-II-induced proinflammatory cytokines production along with the reduction in the levels of serum cholesterol, LDL and triglycerides while increasing the HDL levels. Taken together, it is concluded that Mito-Esc greatly protects oxidant-induced endothelial cell death and atherosclerosis in ApoE −/− mice by modulating intracellular pathways regulating nitric oxide levels and inflammatory cascades, indicating that the formula 1 is an antioxidant compound.
BRIEF DESCRIPTION OF DRAWINGS
[0018] FIGS. 1A and 1B . Mitochondria-targeted esculetin (Mito-Esc) but not esculetin protects endothelial cells from H 2 O 2 and Ang-II-induced cell death in human aortic endothelial cells (HAEC). Cells were treated with Mito-Esc or Esc (2.5 μM) for 24 h. FIG. 1A shows the cell viability by trypan blue assay and FIG. 1B shows the caspase-3 and -8 activation.
[0019] FIGS. 2A and 2B . Mitochondria-targeted esculetin (Mito-Esc) restores H 2 O 2 -induced mitochondrial membrane depolarization in HAEC. Cells were treated with Mito-Esc (2.5 μM) for 16 h. FIG. 2A shows the H 2 O 2 generation with Ang-II treatment and the effect of Mito-Esc on Ang-II-induced H 2 O 2 production and FIG. 2B represents the mitochondrial membrane potential measured as described in Experimental section.
[0020] FIGS. 3A through 3F . Mito-Esc induced nitric oxide generation is mediated by increased eNOS phosphorylation in HAEC. In FIG. 3A cells were treated with H 2 O 2 (500 μM) in the presence or absence of Mito-Esc (2.5 μM) or esculetin (2.5 μM) for a period of 8 h and nitric oxide levels were measured by employing DAF-2A as described in the experimental section. In FIG. 3B and FIG. 3C cells were treated with various concentrations of Mito-Esc (1-5 μM) for 8 h and eNOS and phospho-eNOS protein levels were measured by Western blot analysis as mentioned in the Experimental Section. In FIG. 3D cells were treated with Ang-II (500 nM) in the presence or absence of Mito-Esc (2.5 μM) for 8 h and eNOS and phospho-eNOS protein levels were measured. FIG. 3E same as FIG. 3A except that eNOS and phospho-eNOS protein levels were measured by Western blot analysis. In FIG. 3F cells were treated with either H 2 O 2 (500 μM) or Ang-II (500 nM) in the presence or absence of either Mito-Esc or L-NAME (2 mM) for 24 h and cell viability was measured by trypan blue exclusion assay as described in Experimental Section.
[0021] FIGS. 4A through 4C . Effect of Mito-Esc on AMPK phosphorylation in endothelial cells. In FIG. 4A , HAEC were treated with various concentrations of Mito-Esc (1-5 μM) for 8 h and AMPK and phospho-AMPK protein levels were measured by Western blot analysis. In FIG. 4B , cells were treated with H 2 O 2 (500 uM) in the presence or absence of either Mito-Esc (2.5 μM) or esculetin (2.5 μM) for 8 h and AMPK and phospho-AMPK protein levels were measured by Western blot analysis. In FIG. 4C , same as FIG. 4B except that cells were treated with Ang-II (500 nM) in the presence or absence of Mito-Esc or esculetin.
[0022] FIGS. 5A through 5E . Mito-Esc increases mitochondrial biogenesis in HAEC through the upregulation of SIRT3, PGC-1α and TFAM in endothelial cells. In FIG. 5A , cells were treated with H 2 O 2 in the presence or absence of Mito-Esc for 8 h and mitochondrial staining was performed employing Mitotracker dye as described in the experimental section. FIG. 5B shows the quantification of data shown in FIG. 5A by Image analysis software. In FIG. 5C , HAEC were treated with various concentrations of Mito-Esc (1-5 μM) for 8 h and SIRT3 protein levels (marker of mitochondrial biogenesis) were measured by Western blot analysis. In FIG. 5D , cells were treated with Ang-II (500 nM) in the presence or absence of Mito-Esc (2.5 μM) for 8 h and RT-PCR was performed for TFAM and PGC-1α (markers of mitochondrial biogenesis) using gene specific primers. In FIG. 5E , cells were treated with Ang-II (500 nM) in the presence or absence of Mito-Esc (2. 5 μM) for 8 h and SIRT3 and PGC-1α protein levels were measured by Western blot analysis.
[0023] FIGS. 6A and 6B . Mito-Esc delays endothelial cell aging and also inhibits oxidative stress-induced cell senescence. In FIG. 6A , HAEC were grown in the presence or absence of Mito-Esc (2.5 uM) for 6 passages/generations (P10 to P16) and then stained with senescence-associated b-Gal staining solution as described in the Experimental Section. In FIG. 6B , cells (P8 passage, representing young cells) were treated with H 2 O 2 (500 uM) in the presence or absence of Mito-Esc (2.5 μM) for 24 h and stained with senescence-associated b-Gal staining solution as described in the Experimental Section.
[0024] FIGS. 7A through 7E . Mito-Esc administration inhibits Ang-II induced atherosclerosis in ApoE −/− mice aorta. In FIG. 7A , thoracic and abdominal aortic diameters in control, Ang-II and Ang-II+ Mito-Esc treated groups. Animal experiment protocol is described in the Experimental Section. FIG. 7B represents percent aortic aneurysm incidence and, in FIG. 7C , percent plaque incidence. In FIG. 7D , histopathological images of aorta stained with Hemaoxylene & Eosin (showing the plaque formation) and, FIG. 7E , Mason-trichome (showing the fibrosis, blue color). Parenthesis indicates number of animals exhibited Aortic Aneurysm or plaque incidence.
[0025] FIGS. 8A and 8B . Mito-Esc administration restores Ang-II induced inhibition of eNOS and AMPK phosphorylations in ApoE −/− mice aorta. eNOS and AMPK protein phosphorylation levels were measured in whole aortic tissue homogenates by Western blot analysis.
[0026] FIGS. 9A through 9E . Mito-Esc administration inhibits Ang-II induced proinflammatory cytokines production in ApoE −/− mice. FIG. 9A , FIG. 9B , FIG. 9C , and FIG. 9D show the levels of serum tumor necrosis factor (TNF-α), interferon gamma (IFN-γ), macrophage colony stimulating factor-1 (MCP-1) and interleukin-6 (IL-6) respectively at the end of the 45 days animal protocol as described in the Experimental Section. FIG. 9E shows the levels of Mac-3 (inflammatory macrophage marker) in serum at 15 and 30 days during the treatment protocol.
DETAILED DESCRIPTION OF THE INVENTION
Procedure for the Synthesis of Compound C:
[0027] Compound B (0.505 mL, 3.77 mmol) was taken in dry THF (10 mL) under nitrogen atmosphere and the temperature was cooled to −75 to −80° C. A solution of LDA (2 M in THF, 3.77 mL, 7.54 mmol) was added slowly to the reaction mixture at −78° C. and the resulting mixture was stirred for 1 h. A solution of compound A (1 g, 3.77 mmol) in dry THF (10 mL) was cooled to −78° C. in another flask. A solution of t-butyl lithiate B was added to compound A slowly at −78° C. and the resulting mixture was stirred at the same temperature for 1 h. The reaction progress was monitored by TLC. After completion, the reaction mixture was quenched with water (10 mL) and extracted with ethyl acetate (3×20 mL), the combined organic extracts were washed with water (20 mL) and dried over anhydrous Na 2 SO 4 filtered and concentrated under vacuum to afford the crude product (1.2 g) as colorless oil. The crude product was directly used as such in next step without any purification.
Procedure for the Synthesis of Compound E:
[0028] A mixture of compound 3 (2.6 g, crude, 7.761 mmol) and compound D (1.95 g, 7.761 mmol) in 75% aqueous H 2 SO 4 (26 mL) was stirred at RT for 18-20 h. The reaction progress was monitored by TLC. After completion, the reaction mixture was diluted with water (50 mL) and extracted with ethyl acetate (2×25 mL). The combined organic extracts were washed with water and dried over Na 2 SO 4 , filtered and concentrated under vacuum to obtain crude compound. The crude product was purified by flash column chromatography (Silica gel: 100-200 mesh) eluting with 50% ethyl acetate in hexane to afford the desired compound 5 (300 mg, Yield: 22%) as pale yellow solid.
1 H NMR (400 MHz, DMSO-d6): δ1.31-1.37 (m, 8H), 1.57-1.61 (m, 2H), 1.77-1.80 (m, 2H), 2.67-2.63 (t, 2H, J=7.6 Hz), 3.53-3.50 (t, 2H, J=6.6 Hz), 6.05 (s, 1H), 6.73 (s, 1H), 7.04 (s, 1H), 9.12 (br, 1H), 10.4 (br, 1H). LCMS Purity: 93.88%, 371.15 (M+H).
Procedure for the Synthesis of Esucletin Analogue F:
[0030] To a stirred solution of compound E (140 mg, 0.379 mmol) in dry DMF (5 mL) was added TPP (99 mg, 0.379 mmol) and the resulting mixture was heated to 150-170° C. for 5-8 h. The progress of the reaction was monitored by TLC. After completion of the reaction, DMF was distilled off completely under reduced pressure to obtain crude compound. The crude product was washed several times with ethyl acetate and diethyl ether to afford the esucletin analog F (Yield: 140 mg, 57.8%) as pale brown solid.
1 H NMR (400 MHz, CD 3 OD): δ1.34-1.42 (m, 6H), 1.53-1.56 (m, 2H), 1.61-1.69 (m, 4H), 2.68-2.72 (t, 2H, J=7.6 Hz), 3.34-3.41 (m, 2H), 6.04 (s, 1H), 6.74 (s, 1H), 7.07 (s, 1H), 7.72-7.89 (m, 15 H). LCMS Purity: 88.99%, 551 (M-Br).
Endothelial Cell Experiments.
[0032] Human aortic endothelial cells (HAECs) were obtained from ATCC (Manassas, Va.) and maintained (37° C. 5% CO 2 ) in basal medium supplemented with 10% FBS, VEGF (5 ng/mL), hEGF (5 ng/mL), hFGF (5 ng/mL), IGF-1 (15 ng/mL), ascorbic acid (50 μg/mL), hydrocortisone (1 μg/mL), amphotericin (15 ng/mL), gentamicin (30 ng/mL) and heparin (0.75 Units/mL). Cells used in this study were between passages 4 and 9. Esculetin, Mito-Esc, TPP and nitric oxide synthase inhibitor (L-NAME) were added 2 h before the addition of H 2 O 2 or Ang-II.
Animal Experiments.
[0033] Experiments were conducted in 2-month-old male apolipoprotein E knockout (ApoE −/− ) mice according to the guidelines formulated for care and use of animals in scientific research (ICMR, New Delhi, India) at a CPCSEA (Committee for the Purpose of Control and Supervision of Experiments on Animals) registered animal facility. The experimental protocols were approved by the Institutional Animal Ethical Committee at CSIR-IICT (IICT/CB/SK/20/12/2013/10). Animals were randomly divided into 3 groups each n=7:1) control 2) Ang-II treatment and 3) Mito-Esculetin+Ang-II treatment. Ang-II and Mito-Esculetin treatment groups received Ang-II (sigma) at a dose of 1.44 mg/kg/day for 6 weeks through sub-cutaneous route where as control group received normal saline. Mito-Esculetin treatment group received the compound at a dose of 0.5 mg/kg/day in normal drinking water. All animals were fed on normal chow throughout the study. After 6 weeks, all groups of animals were sacrificed as per standard protocols for euthanasia.
Trypan Blue Cell Viability Assay.
[0034] At the end of the treatments, cells were harvested and re-suspended in 0.4% trypan blue (Life Technologies) and percent cell viability was counted using cell countess chamber (Life Technologies).
Caspase Activity.
[0035] At the end of the treatments. HAEC were washed twice with cold DPBS and lysed in buffer containing 10-mM Tris-HCl, 10-mM NaH 2 PO 4 /Na 2 HPO 4 (pH.7.5). 130-mM NaCl. 1% Triton, and 10-mM sodium pyrophosphate. Cell lysates were incubated with either with caspase-3 fluorogenic substrate (N-acetyl-Asp-Glu-Val-Asp-7-amido-4-methylcoumarin) or caspase-8 fluorogenic substrate (N-acetyl-Ileu-Glu-Thr-Asp-7 amido-4-methylcoumarin) at 37° C. for 1 h. The 7-amido-4-methyl-coumarin liberated was measured in a multi mode reader (PerkinElmer) with λex=380 nm and λem=460 nm.
[0000] Measurement of H 2 O 2 Levels.
[0036] Amplex red reagent was used to detect the released H 2 O 2 from cells. At the end of the treatments, HAECs were trypsinized and 20,000 cells were resuspended in 100 μl of Kreb's ringer phosphate buffer (pH, 7.35) and the assay was initiated by mixing with 100 μl of Krebs-Ringer buffer solution containing 50 μM amplex red reagent along with 0.1 U/mL horseradish peroxidase (HRP). Immediately, formation of resorufin fluorescence was measured in multi mode reader (PerkinElmer) with λex=540 and λem=585.
Detection of Mitochondrial Transmembrane Potential Changes.
[0037] Mitochondrial potential was assessed by using the fluorescent potentiometric JC-1 dye. In healthy cells, JC-1 forms J-aggregates that display a strong red fluorescence with excitation of 560 nm and emission wavelength at 595 nm. In apoptotic or unhealthy cells, JC-1 exists as monomers that display a strong green fluorescence with excitation and emission at 485 nm and 535 nm, respectively. At the end of the treatments, cells were washed with Dulbeccos phosphate buffer solution (DPBS) and incubated with JC-1 dye (5 mg/ml) for 20 min. Cells were again washed twice with DPBS and maintained in culture medium. Fluorescence was monitored by using Olympus fluorescence microscope with Rhodamine and Fluorescein isothiocyanate (FITC) filters.
Measurement of Intracellular Nitric Oxide Levels.
[0038] Intracellular nitric oxide levels were monitored by using the Diaminofluorescein-diacetate (DAF-2DA) fluorescence probe. After the treatments, cells were washed with DPBS and incubated in fresh culture medium without fetal bovine serum (FBS). DAF-2DA was added at a final concentration of 5 μM, and the cells were incubated for 30 minutes. The cells were washed twice with DPBS and maintained in culture medium. Fluorescence was monitored by using Olympus fluorescence microscope with FITC filter (λex=488 nm and λem=610 nm). Fluorescence intensity was calculated by Image-Pro plus7.0 software.
Mitotracker Staining.
[0039] Mitochondrial content in cells was assessed by selectively loading the mitochondria with the red fluorescent dye Mitotracker (Invitrogen, Carlsbad, Calif.).
Western Blot Analysis.
[0040] At the end of the treatments, HAECs were washed with ice-cold DPBS and resuspended in RIPA buffer (20 mM Tris-HCl, pH 7.4/2.5 mM EDTA/1% Triton X-100/1% sodium deoxycholate/1% SDS/100 mM NaCl/100 mM sodium fluoride) containing protease inhibitor cocktail and phosphatase inhibitor cocktail-2 and -3. The lysate was centrifuged for 15 min at 12000×g. Proteins were resolved on 8% SDS-PAGE and blotted onto nitrocellulose membrane and probed with rabbit anti-p-eNOS (ser-1177), rabbit anti-eNOS, rabbit anti-p-AMPK-1α. (Thr-172) and rabbit anti-AMPK antibodies and then incubated with horseradish peroxidase-conjugated goat anti-rabbit IgG secondary antibody (1:5000). Protein bands were detected by using HRP substrate (Millipore-luminata). All the antibodies used for this study were from CST.
[0000] Isolation of Cytosolic and Mitochondrial Fractions from HAEC's and Apo E −/− Mice Aortic Tissue.
[0041] HAECs were grown in 90-mm dishes, treated with or without Mito-Esculetin (2.5 μM) for 24 h. After the treatment, cells were washed thrice with PBS. Similarly Mito-Esculetin+ Ang-II treatment group, Ang-II alone treatment group and control Apo E −/− mice aortic tissue was taken. The isolation of mitochondrial and cytosolic extracts was carried out using a commercially available Proteo Extract Cytosol/Mitochondria Fractionation Kit (Cat.no. QIA88-Merck, USA) according to manufacturer's instructions.
Measurement of Mitochondrial Bioenergetics.
[0042] The oxygen consumption rate (OCR) and extracellular acidification rates in HAEC treated with Mito-Esculetin (2.5 uM) for 24 h was measured using Seahorse XF24-extracellular flux analyzer (Seahorse Biosciences, North Billerica Mass.) according to the manufacturer's protocol.
β-Galactosidase (β-Gal) Staining.
[0043] Low and high passage number (which reflects young and aged) endothelial cells (HAEC) cells were treated with various concentrations of H 2 O 2 (50-500 μM)) for 8 h. Cells were washed in PBS, fixed for 3-5 mM (room temperature) in 2% formaldehyde/0.2% glutaraldehyde, washed, and incubated at 37° C. with fresh senescence associated β-Gal (SA-,β-Gal) stain solution: 1 mg of 5-bromo-4-chloro-3-indolyl β-D-galactoside (X-Gal) per ml (stock=20 mg of dimethylformamide per ml)/40 mM citric acid/sodium phosphate, pH 6.0; 5 mM potassium ferrocyanide/5 mM potassium ferricyanide/150 mM NaCl/2 mM MgCl 2 . Staining was visualized after 24 h using a phase contrast microscope.
Detection and Quantification of Mito-Esc by Mass Spectrometry.
[0044] Initially, mitochondrial and cytosolic fractions were separated using a commercially available kit as mentioned elsewhere. Mito-Esc was quantified in the mitochondrial and cytosolic fractions obtained from HAEC and aorta of ApoE −/− mice of different treatment groups as mentioned in Animal Experiments section (Table-1). Electrospray ionization (ESI)-MS. ESI-MS (positive mode) measurements were performed using a quadrupole time-of-flight mass spectrometer (QSTAR XL, Applied Biosystems/MDS Sciex, Foster City, Calif., USA). The data acquisition was under the control of Analyst QS software (Applied Biosystems). For the CID (collision-induced dissociation) experiments, the precursor ions were selected using the quadrupole analyzer and the product ions were analyzed using the TOF analyzer.
The detailed description of these inventions is explained with following examples but these should not construe to limit the invention.
EXAMPLE 1
[0046] Mitochondria-targeted esculetin (Mito-Esc) but not native esculetin abrogates oxidant-induced cell death in human aortic endothelial cells (HAEC)—We have studied the effects of mitochondria-targeted esculetin (Mito-Esc) (2.5 μM) as well as the native esculetin (2.5 μM) on Ang-II (500 nM) and H 2 O 2 (500 μM)-induced endothelial cell death. For this, cells were pretreated for 2 h with either Mito-Esc or esculetin before they were incubated with either H 2 O 2 or Ang-II. Mito-Esc but not esculetin significantly inhibited oxidant (H 2 O 2 and Ang-II)-induced endothelial cell death ( FIG. 1C ). However, TPP + alone did not have any appreciable cytotoxic/cytoprotective effect in HAEC ( FIG. 2C ). Thereby, indicating that the observed protective effect of Mito-Esc is not because of the TPP + side chain coupled to esculetin. Next, to confirm that H 2 O 2 and Ang-II caused an apoptotic mediated cell death in HAEC, we measured caspase-3 and -8 activities in cells treated with same conditions as shown in FIG. 1B . The results showed that Mito-Esc-pretreated cells were markedly resistant to H 2 O 2 and Ang-II-induced caspase activation, whereas treatment with native esculetin elicited marginal effect on caspase-3 and -8 activation in H 2 O 2 and Ang-II treated cells as compared to Mito-Esc ( FIG. 2D ). These results are consistent with the cell death measured by trypan blue dye exclusion method.
EXAMPLE 2
[0047] Mito-Esc decomposes Ang-II-induced H 2 O 2 generation and preserves oxidant mediated depolarization of mitochondrial membrane potential—Ang-II is known to increase oxidative stress through increased production of H 2 O 2 (Doughan A K, Harrison D G, Dikalov S I. Circ Res (2008) 102:488-96). To see the effect of Mito-Esc in regulating Ang-II-induced H 2 O 2 production in endothelial cells, HAEC were treated with Ang-II (500 nM) in the presence or absence of Mito-Esc (2.5 μM) for a period of 16 h and H 2 O 2 production was measured by Amplex red assay. In cells treated with Ang-II, H 2 O 2 generation was significantly increased by around 2.7 fold compared to untreated conditions ( FIG. 2A ). Interestingly, Mito-Esc co-treatment completely reversed H 2 O 2 levels to control conditions ( FIG. 3A ). Thereby suggesting that Ang-II-induced cytotoxicity in HAEC involves oxidative stress and that co-incubation of HAEC with mito-Esc greatly attenuates Ang-II-mediated cell death by decomposing H 2 O 2 levels. Further, we assessed the effect of Mito-Esc on H 2 O 2 -induced mitochondrial membrane depolarization. HAEC were treated with H 2 O 2 (500 μM) in the presence or absence of Mito-Esc for a period of 16 h and mitochondrial membrane potential was measured using a mitochondrial membrane sensor kit. Mito-Sensor is a cationic dye that fluoresces differently in apoptotic and nonapoptotic cells. The Mito-Sensor dye forms aggregates in mitochondria of healthy cells and exhibits a red fluorescence. In apoptotic cells, membrane potentials are altered and the Mito-Sensor dye cannot accumulate in mitochondria and, thus, remain as monomers leading to a green fluorescence. In agreement with the results shown in FIG. 1 and FIG. 2A , Mito-Esc significantly rescued H 2 O 2 -mediated mitochondrial membrane depolarization ( FIG. 2B ). These results indicate that Mito-Esc by decomposing mitochondria-derived H 2 O 2 , protects endothelial cells during oxidant stress.
EXAMPLE 3
[0048] Mito-Esc potentiates nitric oxide generation via increased eNOS phosphorylation in HAEC: Effect of NOS inhibitor on Mito-Esc-mediated inhibition of oxidant mediated cell death—To gain mechanistic insight on Mito-Esc-mediated protection of endothelial cells from oxidant-induced endothelial cell death, initially we hypothesized that Mito-Esc may augment intracellular nitric oxide generation. To study this, HAEC were treated with both Mito-Esc and esculetin in the presence or absence of H 2 O 2 for a period of 4 h and nitric oxide (NO) levels were monitored by DAF-2 derived green fluorescence. Previously, it has been shown that DAF-2 forms a fluorescent triazole-type product in the presence of an oxidant derived from nitric oxide and oxygen interaction (Proc. Natl. Acad. Sci. USA 99: 11127-11132; 2002.; Am. J. Physiol. Regul. Integ. Comp. Physiol. 286:R344-R431; 2004). Intriguingly, Mito-Esc alone but not native esculetin greatly enhanced the DAF-2 fluorescence in HAEC ( FIGS. 4A and 4B ). Thereby indicating that incubation of endothelial cells with Mito-Esc causes an increase in NO production. Also, Mito-Esc significantly restored H 2 O 2 -mediated depletion of NO levels ( FIGS. 4A and 4B ). However, under these conditions, native esculetin did not show any noticeable effect on NO generation ( FIGS. 4A and 4B ). Next, we investigated the possible role of endothelial nitric oxide synthase (eNOS) in mediating the Mito-Esc induced NO generation in HAEC. For this, endothelial cells were treated with various concentrations of Mito-Esc (1-5 μM) for a period of 8 h. Mito-Esc dose-dependently increased the phosphorylation of eNOS at Ser-1177 ( FIG. 4C ). To further substantiate the results of DAF fluorescence, eNOS phosphorylation was measured in HAEC incubated with either with H 2 O 2 or Ang-II for 8 h in cells pretreated with Mito-Esc or native esculetin. It was observed that both H 2 O 2 and Ang-II caused a reduction in Phospho eNOS (Ser-1177) levels ( FIG. 4D ). Ang-II treatment imposed a drastic inhibition of phospho-eNOS levels when compared to H 2 O 2 treatment in endothelial cells ( FIG. 4D ). Under these conditions, however, Mito-Esc but not native esculetin treatment caused cells resistant to oxidant-mediated decrease in eNOS-phosphorylation ( FIG. 4D and FIG. 4E ). Furthermore, incubation of cells with L-NG-Nitro-L-arginine (L-NAME), a known NOS inhibitor; significantly abrogated Mito-Esc-mediated cyto-protective effects against oxidant-induced cell death ( FIG. 4G ). Taken together, these results suggest that Mito-Esc mediated increase in nitric oxide generation via increased phosphorylation of eNOS is in part responsible for maintaining endothelial cell viability during oxidative stress.
EXAMPLE 4
[0049] Mito-Esc mediated increase in eNOS phosphorylation and NO generation is caused by increased activation of AMPK—Previously, it was shown that AMPK co-immunoprecipitates with cardiac endothelial NO synthase (eNOS) and phosphorylates Ser-1177 in the presence of Ca 2+ -calmodulin (CaM) to activate eNOS both in vitro and during ischaemia in rat hearts (FEBS Lett. (1999) 443:285-289). To test whether Mito-Esc mediates increased phosphorylation of eNOS through AMPK activation, initially, HAEC were treated various concentrations of Mito-Esc (1-5 μM) for 8 h and AMPK1-α phosphorylation (Thr-172) levels were measured. Mito-Esc lead to a dose-dependent increase in phospho-AMPK1-α (Thr-172) levels with maximum effect at 2.5 μM of Mito-Esc ( FIG. 4A ). Next, we investigated the phospho-AMPK1-α levels in HAEC treated with H 2 O 2 in the presence or absence of either Mito-Esc or native esculetin. Incubation of cells with either H 2 O 2 alone or in the presence of native esculetin for 8 h significantly decreased AMPK1-α phosphorylation and whereas incubation of cells with either Mito-Esc alone or in the presence of H 2 O 2 greatly enhanced the phospho-AMPK1-α 0 levels ( FIG. 4B ). Similar results were obtained with Ang-II treatment, where it was found that Ang-II treatment significantly down regulated phospho-AMPK1-α levels and that co-incubation with Mito-Esc made cells resistant to Ang-II-mediated inhibition of phospho-AMPK1-α ( FIG. 4C ).
EXAMPLE 5
[0050] Mito-Esc treatment increases mitochondrial biogenesis by increasing SIRT-3, PGC-1A and TFAM expressions—To see if Mito-Esc treatment modulates oxidant-induced deregulation of mitochondrial biogenesis, we have treated HAEC with either H 2 O 2 (500 μM) or Ang-II (500 nM) in the presence or absence of Mito-Esc (2.5 μor 8 h and then initially measured mitochondrial content using Mitotracker dye. It was found that Mito-Esc treatment significantly restored the oxidant-induced depletion of mitochondrial content ( FIGS. 5A and B). In fact, mito-Esc treatment alone increased mitochondrial content when compared to control. Next we investigated the ability of Mito-Esc to modulate the mitochondrial biogenetic regulators namely, silent mating type information regulation 2 homolog (SIRT)-3, Peroxisome proliferator-activated receptor-gamma coactivator (PGC)-1α and mitochondrial transcription factor A (TFAM). It was found that Mito-Esc treatment (1-5 μM) significantly increased SIRT-3 levels in HAEC treated for 8 h ( FIG. 5C ). Similarly, Mito-Esc (2.5 μM) significantly increased both RNA and protein levels of PGC-1α, TFAM in cells treated for 8 h. Consistent with FIG. 5A , Mito-Esc treatment significantly reversed the Ang-II treatment induced inhibition of PGC-1A, TFAM and SIRT-3 levels ( FIGS. 5D and E).
EXAMPLE 6
[0051] Mito-Esc delays endothelial cell aging and also inhibits oxidative stress-induced cell senescence—To study if Mti-Esc influences vascular aging; we have studied its effect on human aortic endothelial cell (HAEC) aging. For this, we used HAEC of different passages (representing different age) from P6 (young age) to P16 (old age). Also we have grown HAEC with Mito-Esc (2. 5 μM) for six generations (six passages) to understand its chronic effects in regulating endothelial cell aging phenomenon. Results indicated that a chronic treatment of Mito-Esc greatly attenuated endothelial cell aging as evidenced by a significant reduction in the senescence-associated β-gal staining ( FIG. 6 A). Thereby, suggesting that Mito-Esc treatment delays endothelial cell aging. Also, interestingly, Mito-Esc significantly inhibited H 2 O 2 -induced premature senescence in P6 (young age) HAEC ( FIG. 6B ).
EXAMPLE 7
[0052] Mito-Esc administration attenuates the incidence of Ang-II-induced aortic aneurysm and atheromatous plaque formation in ApoE −/− mice—It is well documented that endothelial dysfunction is the most dominant risk factor for the development of vascular disorders including atherosclerosis. In relation to this, we have investigated the physiological significance of Mito-Esc in attenuating Ang-II-induced aortic aneurysm and atherogenesis in ApoE −/− mice model. Grossly, thoracic and abdominal aorta of Ang-II+Mito-Esc treated group showed a significant reduction in Ang-II-induced a) plaque extension, b) multiple numbers of micro/pseudo aneurysm formation and the c) maximal aortic diameters ( FIGS. 7A , B and C) at the end of six weeks. These changes in Ang-II+Mito-Esc group were comparable to control group mice. We further analyzed the vascular remodelling employing histological stains in tissue sections of thoracic aortas. H&E staining of Ang-II+Mito-Esc treated group aorta showed a complete protection from Ang-II treatment alone induced severe atherosclerotic lesions with thick walls, intimal plaques. It was also noticed that the luminal diameter was significantly restored in Ang-II+Mito-Esc treated mice compared to Ang-II alone treated mice ( FIG. 7D ). Masson trichrome staining revealed thick fibrous mature connective tissue surrounding/in between atheroma in Ang-II treated mice aorta which was almost disappeared in Ang-II+Mito-Esc treated group ( FIG. 7E ). The collagen tissue in the atheroma, intimal, medial and external region appeared as blue color indicative of extensive proliferation of collagen tissue occurred in the atheromatous region of Ang-II treated mice. To further corroborate Mito-Esc's ability to protect from Ang-II-induced endothelial dysfunction during the progression of atheromatous plaque formation, we measured phospho-AMPK, AMPK, phospho-eNOS and eNOS protein levels in total aorta lysate. Intriguingly, Ang-II+Mito-Esc mice showed a significant increase in the phosphorylation statuses of both Enos and AMPK as compared to either Ang-II alone treatment or control groups ( FIGS. 8A and B). These results are in agreement with cell culture results wherein, Mito-Esc treatment greatly increased phosphorylation of both eNOS and AMPK in HAEC. This suggests that Mito-Esc by increasing eNOS-derived nitric oxide generation restores endothelial function in Ang-II treated ApoE −/− mice. Along these lines, Ang-II+Mito-Esc treated mice showed a significant inhibition of Ang-II-induced proinflammatory cytokines (TNF-α, IFN-γ, MCP-1) production ( FIGS. 9A-D ). In tune with this, we have also measured Mac-3 levels by flow cytometry. Mac-3 is a general marker for macrophage abundance often seen under inflammatory conditions. Ang-II treatment greatly elevated Mac-3 levels by 30 days of treatment protocol, indicating an increased macrophage accumulation ( FIG. 7G ). However, Ang-II+Mito-Esc group showed an inhibition of Mac3 levels during this time ( FIG. 9E ). Finally, to extend the vasculo-protective effects of Mito-Esc, it was observed that Mito-Esc treatment significantly reduced Ang-II mediated increase in the levels of LDL, VLDL, triglycerides and total cholesterol (Table 2). Also importantly, Mito-Esc treatment resulted in a significant rise in serum HDL levels (Table 2). Taken together, all these results implicate that Mito-Esc treatment significantly eases the incidence of vascular complications including plaque formation and aortic aneurysm.
[0000]
TABLE 1
Cellular uptake of Esculetin and Mito-Esculetin
Cytosolic fraction
Mitochondrial fraction
(nmol/mg protein)
(nmol/mg protein)
Esculetin (HAEC)
6249 ± 235
ND
Mito-Esc (HAEC)
4488 ± 104
14523 ± 342
Mito-Esc (Apo E −/−
ND
2547 ± 286
Mice Aorta)
ND indicates Not Detected
[0000]
TABLE 2
Serum lipid profile of Apo E −/− mice treated with Ang-II alone or Ang-II +
Mito-Esc for 45 days and serum lipid profile was measured
Total
Triglycerides
LDL
HDL
VLDL
Cholesterol
(mg/dL)
(mg/dL)
(mg/dL)
(mg/dL)
(mg/dL)
Control
175.33 ± 6.1
165.61 ± 15.6
23.58 ± 1.5
35.6 ± 0.7
364.51 ± 14.2
Ang-II
234.50 ± 21.5
423.93 ± 29.6
02.21 ± 1.2
46.9 ± 2.2
656.19 ± 34.2
Mito-Esc +
150.74 ± 3.8
218.40 ± 20.9
45.53 ± 0.4
30.15 ± 0.4
414.85 ± 8.2
Ang-II | The present invention relates to an antioxidant compound having anti atherosclerotic effect and preparation thereof. The present invention more particularly relates to the synthesis of TPP+ coupled esculetin (mitochondria-targeted esculetin [Mito-Esc]) followed by the biological evaluation of Mito-Esc for its ability to attenuate Angiotensin-II-induced atherosclerosis in apolipoproteinE knockout (ApoE −/− mice along with the endothelial cell age-delaying effects of Mito-Esc. | 2 |
BACKGROUND OF THE INVENTION
[0001] The present invention relates to blood clotting agents/medical devices and methods of controlling bleeding in animals and humans. More particularly, the present invention relates to the effectiveness of a number of different inorganic materials in significantly accelerating the coagulation of blood.
[0002] Blood is a liquid tissue that includes red cells, white cells, corpuscles, and platelets dispersed in a liquid phase. The liquid phase is plasma, which includes acids, lipids, solubilized electrolytes, and proteins. The proteins are suspended in the liquid phase and can be separated out of the liquid phase by any of a variety of methods such as filtration, centrifugation, electrophoresis, and immunochemical techniques. One particular protein suspended in the liquid phase is fibrinogen. When bleeding occurs, the fibrinogen reacts with water and thrombin (an enzyme) to form fibrin, which is insoluble in blood and polymerizes to form clots.
[0003] In a wide variety of circumstances, animals, including humans, can be wounded. Often bleeding is associated with such wounds. In some instances, the wound and the bleeding are minor, and normal blood clotting functions without significant outside aid in stopping the bleeding. Unfortunately, in other circumstances, substantial bleeding can occur. These situations usually require specialized equipment and materials as well as personnel trained to administer appropriate aid. If such aid is not readily available, excessive blood loss can occur. When bleeding is severe, sometimes the immediate availability of equipment and trained personnel is still insufficient to stanch the flow of blood in a timely manner. Moreover, severe wounds can be inflicted in very remote areas or in situations, such as on a battlefield, where adequate medical assistance is not immediately available. In these instances, it is important to stop bleeding, even in less severe wounds, long enough to allow the injured person or animal to receive medical attention. In addition, it may be desirable to accelerate the clotting of even minor wounds to allow the injured person to resume their normal activities.
[0004] In an effort to address the above-described problems, materials have been developed for controlling excessive bleeding in situations where conventional aid is unavailable or less than optimally effective. Although these materials have been shown to be somewhat successful, they are not effective enough for traumatic wounds and tend to be expensive. Furthermore, these materials are sometimes ineffective in all situations and can be difficult to apply as well as remove from a wound. Additionally, or alternatively, some materials, especially those of organic origin, can produce undesirable side effects.
[0005] Compositions for promoting the formation of clots in blood have also been developed. Such compositions include those that contain zeolites and binders. The use of activated zeolites was disclosed by Hursey et al. in U.S. Pat. No. 4,822,349. It was recognized that the use of these activated zeolites in the clotting of blood generated heat and Hursey et al. stated that the heat was important in achieving a cauterization effect as well as increasing coagulation of the blood. In US 2005/0074505 A1, there is described the use of a zeolite that is exchanged with calcium ions to a very high level. Currently clay-bound Ca-exchanged zeolite A is being sold in an activated form by Z-Medica as a hemostatic treatment for hemorrhages. On some occasions, this calcium exchanged zeolite A has been reported to exhibit an undesirable exothermic effect upon use.
[0006] In the treatment of certain conditions and during some surgeries, in order to prevent coagulation of a patient's blood, anticoagulants are routinely administered; the most common of which is heparin. Heparin can be administered in high concentrations during periods of extracorporeal circulation during surgeries such as open heart surgery. During these procedures, the Activated Clotting Time (ACT) and other endpoint based coagulation assays are frequently used to monitor these high levels of heparin and other coagulation parameters.
[0007] Blood clot formation is a complex phase. Several principles are useful in understanding coagulation. In general, the clotting proteins circulate normally as inactive precursors. Coagulation involves a series of activation reactions that in turn act as the catalysts for the next level of reactions and hence, the frequent term “coagulation cascade”. During the reaction(s) process, these proteins and the fibrin mass itself, is highly unstable and water-soluble. This unstable condition will continue until the very final aspects of coagulation. In addition, without (or in limited quantities) those clotting proteins (or in the presence of anticoagulants, i.e., heparin), clotting becomes delayed or prolonged. Eventually, however, fibrin (the foundation of a blood clot) will be formed. This occurs with the cleaving of fibrinogen, one of the coagulation proteins. Finally, Factor XIII (stabilizing factor) is activated by thrombin to yield cross-linked fibrin, which is highly insoluble and stable in formation.
[0008] In 1966, Dr. Paul Hattersley, a physician from California, outlined the design and usage of a fresh whole blood clotting test utilizing a particulate for contact activation. This was to facilitate rapid test conclusion in a clinically meaningful timeframe. The test Hattersley described included placing 1 ml or more of blood into a tube prefilled with 12 mg of activator (diatomaceous earth, Celite®). This tube was prewarmed to body temperature (37° C.) prior to administration of the patient blood sample. A timer was started when blood first entered the test tube. The tube was filled, and inverted a few times to accommodate mixing. The tube was then placed into a 37° C. water bath. At one minute and at every 5 seconds thereafter the tube was removed from the water bath and tilted so that the blood spread the entire length of the tube. The timer was stopped at the first unmistakable signs of a clot. Modifications have been made to the ACT test that determines clotting ability of whole blood over the years including improved instrumentation. A variety of activators are used in the test, including diatomaceous earth, kaolin, glass beads and colloidal silica. A similar test known as the APTT (activated partial thromboplastin time procedure) is used to test the clotting capacity of blood plasma. While the ACT test was first developed over 40 years ago, it only has been found in the present invention that the types of activators that are used to test the coagulation of blood in the laboratory are exceedingly effective in clotting blood from wounds in humans and animals.
SUMMARY OF THE INVENTION
[0009] It has been found that many inorganic materials will accelerate the coagulation of blood. In particular, it has been found that solids that can be used to activate the coagulation of platelet-poor plasma in the APTT clinical test or whole blood in the ACT clinical test will also serve as a coagulation accelerator in vivo. In addition, a variety of other materials have been found that can also accelerate blood clotting. Typical materials that can be used for in-vivo clotting include diatomaceous earth, glass powder or fibers, precipitated or fumed silica, kaolin and montmorillonite clays, Ca exchanged permutites. These materials can be used in an aqueous slurry, dry powder or dehydrated forms, and can also be bound with suitable organic or inorganic binders.
DETAILED DESCRIPTION OF THE INVENTION
[0010] Diatomaceous earth is a naturally occurring, soft, chalk-like sedimentary rock that is easily crumbled into a fine white to off-white powder. This powder has an abrasive feel, similar to pumice powder and is very light, due to its high porosity. It is composed primarily of silica and consists of fossilized remains of diatoms, a type of hard-shelled algae.
[0011] Bioactive glasses are a group of surface reactive glass-ceramics and include the original bioactive glass, Bioglass®. The biocompatibility of these glasses has led them to be investigated extensively for use as implant materials in the human body to repair and replace diseased or damaged bone.
[0012] The apparatus that was used was a TEG® analyzer from Haemoscope Corp. of Morton Grove, Ill. This apparatus measures the time until initial fibrin formation, the kinetics of the initial fibrin clot to reach maximum strength and the ultimate strength and stability of the fibrin clot and therefore its ability to do the work of hemostasis—to mechanically impede hemorrhage without permitting inappropriate thrombosis.
[0000] On unactivated samples:
i. Pipet 360 uL from red topped tube into cup, start TEG test
On activated samples:
i. First, obtain the sample to be tested from lab. They should be weighed, bottled, oven activated (if needed), and capped prior to the start of the experiment. Inorganic solid samples are bottled in twice the amount that needs to be tested. For example, if channel two is to test 5 mg of inorganic solid A and blood, the amount weighed out in the bottle for channel two will be 10 mg. For 10 mg samples, 20 mg is weighed out, etc. See note below for reason. ii. For one activated run, 3 inorganic solid samples were tested at a time. An unactivated blood sample with no additive is run in the first channel. Channels 2, 3 and 4 are blood samples contacted with an inorganic solid. iii. Once ready to test, set one pipet to 720 uL and other pipet to 360 uL. Prepare three red capped tubes (plain polypropylene-lined tubes without added chemicals) to draw blood and prepare three red additional capped tubes to pour the inorganic solid sample into. iv. Draw blood from volunteer and bring back to TEG analyzer. Discard the first tube collected to minimize tissue factor contamination of blood samples. Blood samples were contacted with inorganic solid material and running in TEG machine prior to an elapsed time of 4-5 minutes from donor collection. v. Open bottle 1 and pour inorganic solid into red capped tube. vi. Immediately add 720 uL of blood to inorganic solid in tube. vii. Invert 5 times. viii. Pipet 360 uL of blood and inorganic solid mixture into cup. ix. Start TEG test.
[0023] Note: The proportions are doubled for the initial mixing of blood and inorganic solid because some volume of blood is lost to the sides of the vials, and some samples absorb blood. Using double the volume ensures that there is at least 360 uL of blood to pipet into cup. The proportion of inorganic solid to blood that we are looking at is usually 5 mg/360 uL, 10 mg/360 uL, and 30 mg/360 uL
[0024] The R(min) reported in the Tables below is the time from the start of the experiment to the initial formation of the blood clot as reported by the TEG analyzer. The TEG® analyzer has a sample cup that oscillates back and forth constantly at a set speed through an arc of 4°45′. Each rotation lasts ten seconds. A whole blood sample of 360 ul is placed into the cup, and a stationary pin attached to a torsion wire is immersed into the blood. When the first fibrin forms, it begins to bind the cup and pin, causing the pin to oscillate in phase with the clot. The acceleration of the movement of the pin is a function of the kinetics of clot development. The torque of the rotating cup is transmitted to the immersed pin only after fibrin-platelet bonding has linked the cup and pin together. The strength of these fibrin-platelet bonds affects the magnitude of the pin motion, such that strong clots move the pin directly in phase with the cup motion. Thus, the magnitude of the output is directly related to the strength of the formed clot. As the clot retracts or lyses, these bonds are broken and the transfer of cup motion is diminished. The rotation movement of the pin is converted by a mechanical-electrical transducer to an electrical signal which can be monitored by a computer.
[0025] The resulting hemostasis profile is a measure of the time it takes for the first fibrin strand to be formed, the kinetics of clot formation, the strength of the clot (in shear elasticity units of dyn/cm 2 ) and dissolution of clot. The following data has been collected from volunteer donors. In each case, the unadulterated blood data is included with the data after addition of known amounts of materials.
[0000]
R (min)
Mesoporous Bioactive Glass
Run 7 Bioact glass vial act, 5 mg
8.8
Run 7 Bioact glass vial act, 10 mg
8.3
Run 7 Bioact glass vial act, 30 mg
8.2
Run 7 Bioact glass vial act, 5 mg
8.1
Run 7 Bioact glass vial act, 10 mg
5.9
Run 7 Bioact glass vial act, 30 mg
6.1
Run 3 - 72.8% Si/Ca bioactive glass
13.5
Run 3 - 72.8% Si/Ca bioactive glass
14.6
Run 7
23.8
Run 7
23.0
Run 3
18.2
Run 3
19.3
Diafil 460
Run 1 - vial act Diafil 460, 5 mg
1.6
Run 1 - vial act Diafil 460, 10 mg
1.2
Run 1 - vial act Diafil 460, 30 mg
1.1
Run 2 - Diafil 460 vial act, 5 mg
1.8
Run 2 - Diafil 460 vial act, 10 mg
1.2
Run 2 - Diafil 460 vial act, 30 mg
1.7
Run 1
24.2
Run 2
29.2
Non-mesoporous CaO—SiO2
Run 1 - vial act non-mes CaOSiO2, 5 mg
5.6
Run 1 - vial act non-mes CaOSiO2, 10 mg
5.2
Run 2 - vial act non mes CaOSiO2, 5 mg
5.0
Run 2 - vial act non mes CaOSiO2, 10 mg
4.0
Run 2 - vial act non mes CaOSiO2, 30 mg
2.3
Run 1
29.5
Run 2
19.8
Unactivated Celite 209
Run 3 - vial act Celite 209, 5 mg
2.3
Run 3 - vial act Celite 209, 10 mg
1.6
Run 3 - vial act Celite 209, 30 mg
1.0
Run 10 - vial act Celite 209, 5 mg
2.6
Run 10 - vial act Celite 209, 10, mg
2.5
Run 10 - vial act Celite 209, 10 mg
1.9
Run 3
20.0
Run 10
30.5
Unactivated Celite 270
Run 9 - vial act Celite 270, 5 mg
1.6
Run 9 - vial act Celite 270, 10 mg
1.1
Run 9 - vial act Celite 270, 30 mg
0.8
Run 3 - vial act Celite 270, 5 mg
0.9
Run 3 - vial act Celite 270, 10 mg
1.8
Run 3 - vial act Celite 270, 30 mg
0.8
Run 9
30.7
Run 3
21.1
Calcium Polyphosphate Glass
Run 4 - vial act Ca pphosp glass, 5 mg
10.9
Run 4 - vial act Ca pphosp glass, 10 mg
7.6
Run 4 - vial act Ca pphosp glass, 30 mg
7.0
Run 4 - vial act Ca pphosp glass, 5 mg
9.0
Run 4 - vial act Ca pphosp glass, 10 mg
7.3
Run 4 - vial act Ca pphosp glass, 30 mg
8.2
Run 4
24.8
Run 4
26.2
Siltex - 18
Run 10 - vial Siltex-18, 5 mg
16.2
Run 10 - vial Siltex-18, 10 mg
11.8
Run 10 - vial Siltex-18, 30 mg
6.2
Run 11 - vial Siltex-18, 5 mg
16.9
Run 11 - vial Siltex-18, 10 mg
11.2
Run 11 - vial Siltex-18, 30 mg
7.0
Run 10
20.6
Run 11
33.8
Calcined Zr—Si glass
Run 2 - vial act calc Zr—Si glass, 5 mg
11.2
Run 2 - vial act calc Zr—Si glass, 10 mg
8.0
Run 2 - vial act calc Zr—Si glass, 30 mg
5.0
Run 4 - vial act calc Zr—Si glass, 5 mg
8.9
Run 4 - vial act calc Zr—Si glass, 10 mg
5.9
Run 4 - vial act calc Zr—Si glass, 30 mg
6.2
Run 2
20.8
Run 4
27.9
Hi-Sil 250
Run 11 - vial act Hi-Sil 250, 5 mg
1.9
Run 11 - vial act Hi-Sil 250, 10 mg
1.8
Run 11 - vial act Hi-Sil 250, 30 mg
1.5
Run 12 - vial act Hi-Sil 250, 5 mg
2.7
Run 12 - vial act Hi-Sil 250, 10 mg
2.7
Run 12 - vial act Hi-Sil 250, 30 mg
−110.7
Run 12
31.8
Run 11
18.9
Quartz Sand
Run 4 - vial act Quartz sand, 5 mg
19.6
Run 4 - vial act Quartz sand, 10 mg
12.2
Run 4 - vial act Quartz sand, 30 mg
6.3
Run 4
27.8
[0026] The materials studied include the following:
1. A Mesoporous Bioactive glass with a calcium silicate composition was prepared by formulating the following mixtures:
Mixture A—15 g. of tetraethylorthosilicate, 5.0 g. calcium nitrate tetrahydrate, 20.1 g. of ethanol, 7.5 g deionized water, and 2.5 g. 1 M HCl. Mixture B—A triblock copolymer solution was made by dissolving 20.02 g of Pluronic P123 triblock copolymer (BASF) in 80.12 g of ethanol. Mixture C—45 ml of Mixture B was added to Mixture A and stirred by magnetic stirring for two minutes. The mixture was then heated in an open porcelain crucible at 60° C. for 16 hours, then placed in a furnace and heated at 3° C. per minute to 550° C., held at 550° C. for four hours, then cooled to 100° C. The material was then removed from the furnace and cooled to room temperature.
2. Diafil 460—World Minerals Inc. is headquartered in Santa Barbara, Calif., USA a high surface area ˜30 m 2 /g diatomaceous earth 3. A Ca-silicate sol-gel glass was synthesized by adding 46.8 ml of tetraethylorthosilicate, 21.43 g. of calcium nitrate tetrahydrate, 45 ml of deionized water, and 7.6 ml of 2 M nitric acid to a 250 ml polytetrafluoroethylene bottle. The mixture was hand-shaken briefly and then sealed and heated to 60° C. in a convection oven for 50 hours, then cooled to 25° C. at 0.1° C. per minute. The cap was removed from the bottle then the bottle was returned to the oven and heated from 60° C. to 180° C. at 0.1° C. per minute, then held at 180° C. for 12 hours, followed by cooling to 25° C. at 2.5° C. per minute. The dried gel was then placed in a porcelain dish and heated in a furnace to 105° C. at 0.9° C. per minute, then to 160° C. at 0.2° C. per minute, then to 500° C. at 0.5° C. per minute then to 700° C. at 0.1° C. per minute. The furnace was held at 700° C. for 1 hour then cooled back to 25° C. at 10° C. per minute. The heated material was stored in a desiccator. 4. Celite 209—World Minerals Inc. is headquartered in Santa Barbara, Calif., USA—medium surface area 10-20 m 2 /g diatomaceous earth 5. Celite 270 World Minerals Inc. is headquartered in Santa Barbara, Calif., USA—low surface area 4-6 m 2 /g diatomaceous earth 6. Calcium polyphosphate glass was prepared by heating 64 g of monobasic calcium phosphate monohydrate at 10° C. per minute to 500° C. and held at 500° C. for 15 hours. The material was then heated from 500° C. to 1100° C. at 10° C. per minute then held at 1100° C. for 1 hour. The molten polyphosphate glass was then poured directly into about 1 liter of deionized water. The resulting glass frit was dried at 110° C. for about 1 hour, then was milled in a corundum vibratory mill to a fine powder. 7. Siltex 18—a 97% silica fiberglass cloth—SILTEX is a family of high performance textile fabric that is comprised of high purity, high strength amorphous silica fibers, woven into a strong, flexible fabric designed for use where severe temperature conditions exist. 8. Calcined Zr—Si glass—alkali resistant (AR) glass fibers St. Gobain Group Courbevoie France 9. Hi-Sil 250—a precipitated silica (silica gel)—PPG Industries, Pittsburgh, Pa. 10. Quartz sand—˜99% silica
[0040] Highly significant clot acceleration was observed with the three diatomaceous earth samples and the Hi-Sil 250. Significant acceleration were seen with higher doses of Siltex and AR glass fibers, quartz sand, calcium silicate sol gel glass, and calcium polyphosphate glass.
[0041] Other appropriate hemostatic or absorptive agents may also be added. These include but are not limited to chitosan and its derivatives, fibrinogen and its derivatives (represented herein as fibrin(ogen), e.g. fibrin, which is a cleavage product of fibrinogen, or super-absorbent polymers of many types, cellulose of many types, other cations such as calcium, silver, and sodium or anions, other ion exchange resins, and other synthetic or natural absorbent entities such as super-absorbent polymers with and without ionic or charge properties.
[0042] In addition, the inorganic solid may in addition have added to it vasoactive or other agents which promote vasoconstriction and hemostasis. Such agents might include catecholamines or vasoactive peptides. This may be especially helpful in its dry form so that when blood is absorbed, the additive agents become activated and are leached into the tissues to exert their effects. In addition, antibiotics and other agents which prevent infection (any bacteriocidal or bacteriostatic agent or compound) and anesthetics/analgesics may be added to enhance healing by preventing infection and reducing pain. In addition, fluorescent agents or components could be added to help during surgical removal of some forms of the mineral to ensure minimal retention of the mineral after definitive control of hemorrhage is obtained.
[0043] The formulations of the present invention may be administered to a site of bleeding by any of a variety of means that are well known to those of skill in the art. Examples include but are not limited to internally (e.g. by ingestion of a liquid or tablet form), directly to a wound, (e.g. by shaking powdered or granulated forms of the material directly into or onto a site of hemorrhage), by placing a material such as a bandage that is impregnated with the material into or onto a wound, by spraying it into or onto the wound, or otherwise coating the wound with the material. Bandages may also be of a type that, with application of pressure, bend and so conform to the shape of the wound site. Partially hydrated forms resembling mortar or other semisolid-semiliquid forms, etc. may be used to fill certain types of wounds. For intra-abdominal bleeding, we envision puncture of the peritoneum with a trocar followed by administration of inorganic solids of various suitable formulations.
[0044] Formulations may thus be in many forms such as bandages of varying shapes, sizes and degrees of flexibility and/or rigidity; gels; liquids; pastes; slurries; granules; powders; and other forms. The clay minerals can be incorporated into special carriers such as liposomes or other vehicles to assist in their delivery either topically, gastrointestinally, intTacavitary, or even intravascularly. In addition, combinations of these forms may also be used, for example, a bandage that combines a flexible, sponge-like or gel material that is placed directly onto a wound, and that has an outer protective backing of a somewhat rigid material that is easy to handle and manipulate, the outer layer providing mechanical protection to the wound after application. Both the inner and outer materials may contain clay minerals. Any means of administration may be used, so long as the mineral clay makes sufficient contact with the site of hemorrhage to promote hemostasis.
[0045] Compositions comprising clay minerals may be utilized to control bleeding in a large variety of settings, which include but are not limited to: (a) external bleeding from wounds (acute and chronic) through the use of liquids, slurries, gels, sprays, foams, hydrogels, powder, granules, or the coating of bandages with these preparations; (b) gastrointestinal bleeding through the use of an ingestible liquid, slurry, gel, foam, granules, or powder; (c) epistaxis through the use of an aerosolized powder, sprays, foam, patches, or coated tampon; (d) control of internal solid organ or boney injury through the use of liquids, slurries, sprays, powder, foams, gels, granules, or bandages coated with such; and (e) promotion of hemostasis, fluid absorption and inhibition of proteolytic enzymes to promote healing of all types of wound including the control of pain from such wounds.
[0046] Many applications of the present invention are based on the known problems of getting the surfaces of bandages to conform to all surfaces of a bleeding wound. The use of granules, powders, gels, foams, slurries, pastes, and liquids allow the preparations of the invention to cover all surfaces no matter how irregular they are. For example, a traumatic wound to the groin is very difficult to control by simple direct pressure or by the use of a simple flat bandage. However, treatment can be carried out by using an inorganic material in the form of, for example, a powder, granule preparation, gel, foam, or very viscous liquid preparation that can be poured, squirted or pumped into the wound, followed by application of pressure. One advantage of the preparations of the present invention is their ability to be applied to irregularly shaped wounds, and for sealing wound tracks, i.e. the path of an injurious agent such as a bullet, knife blade, etc. | The present invention is a method to accelerate the coagulation of blood through the application of inorganic materials. Any solid that can be used to activate the coagulation of platelet-poor plasma in the APTT clinical test or whole blood in the ACT clinical test has been found to be effective as a coagulation accelerator in vivo. Typical materials that can be used for in-vivo clotting include diatomaceous earth, glass powder or fibers, precipitated or fumed silica, and calcium exchanged permutites. Thes materials can be used in an aqueous slurry, dry powder or dehydrated forms, and can also be bound with suitable organic or inorganic binders and/or contained in a variety of forms. | 0 |
This application is a continuation of application Ser. No. 08/803,094 filed Feb. 20, 1997, now U.S. Pat. No. 5,735,879, which is a continuation of application Ser. No. 08/103,837 filed Aug. 6, 1993, now abandoned.
BACKGROUND OF THE INVENTION
This invention relates generally to an electrotherapy method and apparatus for delivering a shock to a patient's heart. In particular, this invention relates to a method and apparatus for using an external defibrillator to deliver a biphasic defibrillation shock to a patient's heart through electrodes attached to the patient.
Defibrillators apply pulses of electricity to a patient's heart to convert ventricular arrhythmias, such as ventricular fibrillation and ventricular tachycardia, to normal heart rhythms through the processes of defibrillation and cardioversion, respectively. There are two main classifications of defibrillators: external and implanted. Implantable defibrillators are surgically implanted in patients who have a high likelihood of needing electrotherapy in the future. Implanted defibrillators typically monitor the patient's heart activity and automatically supply electrotherapeutic pulses directly to the patient's heart when indicated. Thus, implanted defibrillators permit the patient to function in a somewhat normal fashion away from the watchful eye of medical personnel.
External defibrillators send electrical pulses to the patient's heart through electrodes applied to the patient's torso. External defibrillators are useful in the emergency room, the operating room, emergency medical vehicles or other situations where there may be an unanticipated need to provide electrotherapy to a patient on short notice. The advantage of external defibrillators is that they may be used on a patient as needed, then subsequently moved to be used with another patient. However, because external defibrillators deliver their electrotherapeutic pulses to the patient's heart indirectly (i.e., from the surface of the patient's skin rather than directly to the heart), they must operate at higher energies, voltages and/or currents than implanted defibrillators. The high energy, voltage and current requirements have made current external defibrillators large, heavy and expensive, particularly due to the large size of the capacitors or other energy storage media required by these prior art devices.
The time plot of the current or voltage pulse delivered by a defibrillator shows the defibrillator's characteristic waveform. Waveforms are characterized according to the shape, polarity, duration and number of pulse phases. Most current external defibrillators deliver monophasic current or voltage electrotherapeutic pulses, although some deliver biphasic sinusoidal pulses. Some prior art implantable defibrillators, on the other hand, use truncated exponential, biphasic waveforms. Examples of biphasic implantable defibrillators may be found in U.S. Pat. No. 4,821,723 to Baker, Jr., et al.; U.S. Pat. No. 5,083,562 to de Coriolis et al.; U.S. Pat. No. 4,800,883 to Winstrom; U.S. Pat. No. 4,850,357 to Bach, Jr.; and U.S. Pat. No. 4,953,551 to Mehra et al.
Because each implanted defibrillator is dedicated to a single patient, its operating parameters, such as electrical pulse amplitudes and total energy delivered, may be effectively titrated to the physiology of the patient to optimize the defibrillator's effectiveness. Thus, for example, the initial voltage, first phase duration and total pulse duration may be set when the device is implanted to deliver the desired amount of energy or to achieve that desired start and end voltage differential (i.e, a constant tilt).
In contrast, because external defibrillator electrodes are not in direct contact with the patient's heart, and because external defibrillators must be able to be used on a variety of patients having a variety of physiological differences, external defibrillators must operate according to pulse amplitude and duration parameters that will be effective in most patients, no matter what the patient's physiology. For example, the impedance presented by the tissue between external defibrillator electrodes and the patient's heart varies from patient to patient, thereby varying the intensity and waveform shape of the shock actually delivered to the patient's heart for a given initial pulse amplitude and duration. Pulse amplitudes and durations effective to treat low impedance patients do not necessarily deliver effective and energy efficient treatments to high impedance patients.
Prior art external defibrillators have not fully addressed the patient variability problem. One prior art approach to this problem was to provide the external defibrillator with multiple energy settings that could be selected by the user. A common protocol for using such a defibrillator was to attempt defibrillation at an initial energy setting suitable for defibrillating a patient of average impedance, then raise the energy setting for subsequent defibrillation attempts in the event that the initial setting failed. The repeated defibrillation attempts require additional energy and add to patient risk. What is needed, therefore, is an external defibrillation method and apparatus that maximizes energy efficiency (to minimize the size of the required energy storage medium) and maximizes therapeutic efficacy across an entire population of patients.
SUMMARY OF THE INVENTION
This invention provides an external defibrillator and defibrillation method that automatically compensates for patient-to-patient impedance differences in the delivery of electrotherapeutic pulses for defibrillation and cardioversion. In a preferred embodiment, the defibrillator has an energy source that may be discharged through electrodes on the patient to provide a biphasic voltage or current pulse. In one aspect of the invention, the first and second phase duration and initial first phase amplitude are predetermined values. In a second aspect of the invention, the duration of the first phase of the pulse may be extended if the amplitude of the first phase of the pulse fails to fall to a threshold value by the end of the predetermined first phase duration, as might occur with a high impedance patient. In a third aspect of the invention, the first phase ends when the first phase amplitude drops below a threshold value or when the first phase duration reaches a threshold time value, whichever comes first, as might occur with a low to average impedance patient. This method and apparatus of altering the delivered biphasic pulse thereby compensates for patient impedance differences by changing the nature of the delivered electrotherapeutic pulse, resulting in a smaller, more efficient and less expensive defibrillator.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic representation of a low-tilt biphasic electrotherapeutic waveform according to a first aspect of this invention.
FIG. 2 is a schematic representation of a high-tilt biphasic electrotherapeutic waveform according to the first aspect of this invention.
FIG. 3 is a flow chart demonstrating part of an electrotherapy method according to a second aspect of this invention.
FIG. 4 is a schematic representation of a biphasic waveform delivered according to the second aspect of this invention.
FIG. 5 is a schematic representation of a biphasic waveform delivered according to the second aspect of this invention.
FIG. 6 is a flow chart demonstrating part of an electrotherapy method according to a third aspect of this invention.
FIG. 7 is a schematic representation of a biphasic waveform delivered according to the third aspect of this invention.
FIG. 8 is a schematic representation of a biphasic waveform delivered according to the third aspect of this invention.
FIG. 9 is a flow chart demonstrating part of an electrotherapy method according to a combination of the second and third aspects of this invention.
FIG. 10 is a block diagram of a defibrillator system according to a preferred embodiment of this invention.
FIG. 11 is a schematic circuit diagram of a defibrillator system according to a preferred embodiment of this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIGS. 1 and 2 illustrate the patient-to-patient differences that an external defibrillator design must take into account. These figures are schematic representations of truncated exponential biphasic waveforms delivered to two different patients from an external defibrillator according to the electrotherapy method of this invention for defibrillation or cardioversion. In these drawings, the vertical axis is voltage, and the horizontal axis is time. The principles discussed here are applicable to waveforms described in terms of current versus time as well, however.
The waveform shown in FIG. 1 is called a low-tilt waveform, and the waveform shown in FIG. 2 is called a high-tilt waveform, where tilt H is defined as a percent as follows: ##EQU1## As shown in FIGS. 1 and 2, A is the initial first phase voltage and D is the second phase terminal voltage. The first phase terminal voltage B results from the exponential decay over time of the initial voltage A through the patient, and the second phase terminal voltage D results from the exponential decay of the second phase initial voltage C in the same manner. The starting voltages and first and second phase durations of the FIG. 1 and FIG. 2 waveforms are the same; the differences in end voltages B and D reflect differences in patient impedance.
Prior art disclosures of the use of truncated exponential biphasic waveforms in implantable defibrillators have provided little guidance for the design of an external defibrillator that will achieve acceptable defibrillation or cardioversion rates across a wide population of patients. The defibrillator operating voltages and energy delivery requirements affect the size, cost, weight and availability of components. In particular, operating voltage requirements affect the choice of switch and capacitor technologies. Total energy delivery requirements affect defibrillator battery and capacitor choices.
We have determined that, for a given patient, externally-applied truncated exponential biphasic waveforms defibrillate at lower voltages and at lower total delivered energies than externally-applied monophasic waveforms. In addition, we have determined that there is a complex relationship between total pulse duration, first to second phase duration ratio, initial voltage, total energy and total tilt.
Up to a point, the more energy delivered to a patient in an electrotherapeutic pulse, the more likely the defibrillation attempt will succeed. Low-tilt biphasic waveforms achieve effective defibrillation rates with less delivered energy than high-tilt waveforms. However, low-tilt waveforms are energy inefficient, since much of the stored energy is not delivered to the patient. On the other hand, defibrillators delivering high-tilt biphasic waveforms deliver more of the stored energy to the patient than defibrillators delivering low-tilt waveforms while maintaining high efficacy up to a certain critical tilt value. Thus, for a given capacitor, a given initial voltage and fixed phase durations, high impedance patients receive a waveform with less total energy and lower peak currents but better conversion properties per unit of energy delivered, and low impedance patients receive a waveform with more delivered energy and higher peak currents. There appears to be an optimum tilt range in which high and low impedance patients will receive effective and efficient therapy. An optimum capacitor charged to a predetermined voltage can be chosen to deliver an effective and efficient waveform across a population of patients having a variety of physiological differences.
This invention is a defibrillator and defibrillation method that takes advantage of this relationship between waveform tilt and total energy delivered in high and low impedance patients. In one aspect of the invention, the defibrillator operates in an open loop, i.e., without any feedback regarding patient impedance parameters and with preset pulse phase durations. The preset parameters of the waveforms shown in FIGS. 1 and 2 are therefore the initial voltage A of the first phase of the pulse, the duration E of the first phase, the interphase duration G, and the duration F of the second phase. The terminal voltage B of the first phase, the initial voltage C of the second phase, and the terminal voltage D of the second phase are dependent upon the physiological parameters of the patient and the physical connection between the electrodes and the patient.
For example, if the patient impedance (i.e., the total impedance between the two electrodes) is high, the amount of voltage drop (exponential decay) from the initial voltage A to the terminal voltage B during time E will be lower (FIG. 1) than if the patient impedance is low (FIG. 2). The same is true for the initial and terminal voltages of the second phase during time F. The values of A, E, G and F are set to optimize defibrillation and/or cardioversion efficacy across a population of patients. Thus, high impedance patients receive a low-tilt waveform that is more effective per unit of delivered energy, and low impedance patients receive a high-tilt waveform that delivers more of the stored energy and is therefore more energy efficient.
Another feature of biphasic waveforms is that waveforms with relatively longer first phases have better conversion properties than waveforms with equal or shorter first phases, provided the total duration exceeds a critical minimum. Therefore, in the case of high impedance patients, it may be desirable to extend the first phase of the biphasic waveform (while the second phase duration is kept constant) to increase the overall efficacy of the electrotherapy by delivering a more efficacious waveform and to increase the total amount of energy delivered. FIGS. 3-5 demonstrate a defibrillation method according to this second aspect of the invention in which information related to patient impedance is fed back to the defibrillator to change the parameters of the delivered electrotherapeutic pulse.
FIG. 3 is a flow chart showing the method steps following the decision (by an operator or by the defibrillator itself) to apply an electrotherapeutic shock to the patient through electrodes attached to the patient and charging of the energy source, e.g., the defibrillator's capacitor or capacitor bank, to the initial first phase voltage A. Block 10 represents initiation of the first phase of the pulse in a first polarity. Discharge may be initiated manually by the user or automatically in response to patient heart activity measurements (e.g., ECG signals) received by the defibrillator through the electrodes and analyzed by the defibrillator controller in a manner known in the art.
Discharge of the first phase continues for at least a threshold time t THRESH , as shown by block 12 of FIG. 3. If, at the end of time t THRESH , the voltage measured across the energy source has not dropped below the minimum first phase terminal voltage threshold V THRESH , first phase discharge continues, as shown in block 14 of FIG. 3. For high impedance patients, this situation results in an extension of the first phase duration beyond t THRESH , as shown in FIG. 4, until the measured voltage drops below the threshold V THRESH . Discharge then ends to complete the first phase, as represented by block 16 of FIG. 3. If, on the other hand, the patient has low impedance, the voltage will have dropped below V THRESH when the time threshold is reached, resulting in a waveform like the one shown in FIG. 5.
At the end of the first phase, and after a predetermined interim period G, the polarity of the energy source connection to the electrodes is switched, as represented by blocks 18 and 20 of FIG. 3. Discharge of the second phase of the biphasic pulse then commences and continues for a predetermined second phase duration F, as represented by block 26 of FIG. 3, then ceases. This compensating electrotherapy method ensures that the energy is delivered by the defibrillator in the most efficacious manner by providing for a minimum waveform tilt and by extending the first phase duration to meet the requirements of a particular patient.
Because this method increases the waveform tilt for high impedance patients and delivers more of the energy from the energy source than a method without compensation, the defibrillator's energy source can be smaller than in prior art external defibrillators, thereby minimizing defibrillator size, weight and expense. It should be noted that the waveforms shown in FIGS. 4 and 5 could be expressed in terms of current versus time using a predetermined current threshold value without departing from the scope of the invention.
FIGS. 6-8 illustrate a third aspect of this invention that prevents the delivered waveform from exceeding a maximum tilt (i.e., maximum delivered energy) in low impedance patients. As shown by blocks 52 and 54 in FIG. 6, the first phase discharge stops either at the end of a predetermined time t THRESH or when the first phase voltage drops below V' THRESH . The second phase begins after an interim period G and continues for a preset period F as in the second aspect of the invention. Thus, in high impedance patients, the first phase ends at time t THRESH , even if the voltage has not yet fallen below V' THRESH , as shown in FIG. 7. In low impedance patients, on the other hand, the first phase of the delivered waveform could be shorter in duration than the time t THRESH , as shown in FIG. 8.
Once again, the waveforms shown in FIGS. 7 and 8 could be expressed in terms of current versus time using a predetermined current threshold value without departing from the scope of the invention.
FIG. 9 is a flow chart illustrating a combination of the defibrillation methods illustrated in FIGS. 3 and 6. In this combination method, the first phase of the biphasic waveform will end if the voltage reaches a first voltage threshold V' THRESH prior to the first phase duration threshold t THRESH , as shown by blocks 91 and 92. This defibrillator decision path delivers a waveform like that shown in FIG. 8 for low impedance patients. For high impedance patients, on the other hand, if at the expiration of t THRESH the voltage has not fallen below V' THRESH , the duration of the first phase is extended beyond t THRESH until the voltage measured across the electrodes reaches a second voltage threshold V THRESH , as shown in decision blocks 91 and 93. This defibrillator method path will deliver a waveform like that shown in FIG. 4.
In alternative embodiments of this invention, the second phase pulse could be a function of the first phase voltage, current or time instead of having a fixed time duration. In addition, any of the above embodiments could provide for alternating initial polarities in successive monophasic or biphasic pulses. In other words, if in the first biphasic waveform delivered by the system the first phase is a positive voltage or current pulse followed by a second phase negative voltage or current pulse, the second biphasic waveform delivered by the system would be a negative first phase voltage or current pulse followed by a positive second phase voltage or current pulse. This arrangement would minimize electrode polarization, i.e., build-up of charge on the electrodes.
For each defibrillator method discussed above, the initial first phase voltage A may be the same for all patients or it may be selected automatically or by the defibrillator user. For example, the defibrillator may have a selection of initial voltage settings, one for an infant, a second for an adult, and a third for use in open heart surgery.
FIG. 10 is a schematic block diagram of a defibrillator system according to a preferred embodiment of this invention. The defibrillator system 30 comprises an energy source 32 to provide the voltage or current pulses described above. In one preferred embodiment, energy source 32 is a single capacitor or a capacitor bank arranged to act as a single capacitor. A connecting mechanism 34 selectively connects and disconnects energy source 32 to and from a pair of electrodes 36 electrically attached to a patient, represented here as a resistive load 37. The connections between the electrodes and the energy source may be in either of two polarities with respect to positive and negative terminals on the energy source.
The defibrillator system is controlled by a controller 38. Specifically, controller 38 operates the connecting mechanism 34 to connect energy source 32 with electrodes 36 in one of the two polarities or to disconnect energy source 32 from electrodes 36. Controller 38 receives timing information from a timer 40, and timer 40 receives electrical information from electrical sensor 42 connected across energy source 32. In some preferred embodiments, sensor 42 is a voltage sensor; in other preferred embodiments, sensor 42 is a current sensor.
FIG. 11 is a schematic circuit diagram illustrating a device according to the preferred embodiments discussed above. Defibrillator controller 70 activates a high voltage power supply 72 to charge storage capacitor 74 via diode 76 to a predetermined voltage. During this period, switches SW1, SW2, SW3 and SW4 are turned off so that no voltage is applied to the patient (represented here as resistor 78) connected between electrodes 80 and 82. SW5 is turned on during this time.
After charging the capacitor, controller 70 de-activates supply 72 and activates biphase switch timer 84. Timer 84 initiates discharge of the first phase of the biphasic waveform through the patient in a first polarity by simultaneously turning on switches SW1 and SW4 via control signals T1 and T4, while switch SW5 remains on to deliver the initial voltage A through electrodes 80 and 82 to the patient 78.
Depending on the operating mode, delivery of the first phase of the biphasic pulse may be terminated by the timer 84 after the end of a predetermined period or when the voltage across the electrodes has dropped below a predetermined value as measured by comparator 86. Timer 84 terminates pulse delivery by turning off switch SW5 via control signal T5, followed by turning off switches SW1 and SW4. The voltage across electrodes 80 and 82 then returns to zero.
During the interim period G, SW5 is turned on to prepare for the second phase. After the end of interim period G, timer 84 initiates delivery of the second phase by simultaneously turning on switches SW2 and SW3 via control signals T2 and T3 while switch SW5 remains on. This configuration applies voltage from the capacitor to the electrodes at an initial second phase voltage C and in a polarity opposite to the first polarity. Timer 84 terminates delivery of the second phase by turning off switch SW5 via control signal T5, followed by turning off switches SW2 and SW3. The second phase may be terminated at the end of a predetermined period or when the voltage measured by comparator 86 drops below a second phase termination voltage threshold.
In a preferred embodiment, switch SW5 is an insulated gate bipolar transistor (IGBT) and switches SW1-SW4 are silicon-controlled rectifiers (SCRs). The SCRs are avalanche-type switches which can be turned on to a conductive state by the application of a control signal, but cannot be turned off until the current through the switch falls to zero or near zero. Thus, the five switches can be configured so that any of the switches SW1-SW4 will close when SW5 is closed and will reopen only upon application of a specific control signal to SW5.
This design has the further advantage that switch SW5 does not need to withstand the maximum capacitor voltage. The maximum voltage that will be applied across switch SW5 will occur when the first phase is terminated by turning SW5 off, at which time the capacitor voltage has decayed to some fraction of its initial value.
Other switches and switch configurations may be used, of course without departing from the scope of the invention. In addition, the defibrillator configurations of FIGS. 10 and 11 may be used to deliver electric pulses of any polarity, amplitude, and duration singly and in any combination.
While the invention has been discussed with reference to external defibrillators, one or more aspects of the invention would be applicable to implantable defibrillators as well. Other modifications will be apparent to those skilled in the art. | This invention provides an external defibrillator and defibrillation method that automatically compensates for patient-to-patient impedance differences in the delivery of electrotherapeutic pulses for defibrillation and cardioversion. In a preferred embodiment, the defibrillator has an energy source that may be discharged through electrodes on the patient to provide a biphasic voltage or current pulse. In one aspect of the invention, the first and second phase duration and initial first phase amplitude are predetermined values. In a second aspect of the invention, the duration of the first phase of the pulse may be extended if the amplitude of the first phase of the pulse fails to fall to a threshold value by the end of the predetermined first phase duration, as might occur with a high impedance patient. In a third aspect of the invention, the first phase ends when the first phase amplitude drops below a threshold value or when the first phase duration reaches a threshold time value, whichever comes first, as might occur with a low to average impedance patient. This method and apparatus of altering the delivered biphasic pulse thereby compensates for patient impedance differences by changing the nature of the delivered electrotherapeutic pulse, resulting in a smaller, more efficient and less expensive defibrillator. | 0 |
TECHNICAL FIELD
[0001] The present disclosure relates to methods and devices for managing a cellular radio network.
BACKGROUND
[0002] The evolved UMTS Terrestrial Radio Access Network (UTRAN) which provides the radio interface in the third generation Partnership Program (3GPP) Long Term Evolution (LTE) architecture consists of radio base stations eNB, providing the evolved UTRAN User Plane (U-plane) and Control Plane (C-plane) protocol terminations towards a User Equipment (UE). The eNBs are interconnected with each other by means of the X2 interfaces. It is assumed that there always exist an X2 interface between the eNBs that need to communicate with each other, e.g., for support of handover of UEs in LTE_ACTIVE mode. This is further defined in 3 GPP release 12 .
[0003] FIG. 1 generally depicts a configuration in an LTE network architecture. FIG. 1 shows the X2 interfaces 16 between the eNBs and also the S1 interfaces 17 between the eNBs and the Mobility Management Entity (MME) and Serving Gateway, (S-GW).
[0004] The X2 interface is used for control plane traffic and optional forwarding of user plane traffic during handover. There is also provision for an S1-based handover but is typically only employed as a fallback option when the X2 interface is not available. Current estimates indicate that the combined X2-c and X2-u traffic could be between 4 and 10 percent of the core-facing bandwidth over the S1-u interface and the delay should be less then 30 ms. This traffic is typically important and from future releases in LTE Advanced, it is envisaged that more user plane traffic will traverse the S1-u interface. Also in Release 11 there will be stringent latency requirements necessary to implement features such as collaborative Multiple Input Multiple Output (MIMO) and Coordinated Multi Point (CoMP).
[0005] The connectivity between eNBs can be provided by the means of Layer 3 (L3) connectivity services. For this purpose, the deployment of Internet Protocol/MultiProtocol Label Switching (IP/MPLS) network elements connecting eNBs is required. In the alternative, the L3 connectivity end point can be implemented at or close to the S-GW site, but this can be associated with some drawbacks: First it may introduce too high communication latency and loading the typically bandwidth-limited backhaul link with inter-eNB traffic. Second implementing L3 end points directly on the backhaul network connecting eNBs, may introduce a too high configuration/provisioning complexity as the operator will have a much higher number of configuration points compared to the centralized solution.
[0006] In both cases a rather static configuration of the L3 end points will typically be the most viable option in order to avoid an even higher configuration complexity, which in turn can cause sub-optimal resource utilization and some pairs of eNBs not directly connected.
[0007] Hence, there is a need for a method and an apparatus that provide an improved utilization of resources in a cellular radio network, in particular an LTE radio network.
SUMMARY
[0008] It is an object of the present invention to provide an improved method and apparatus for improving utilization of resources in a cellular radio network, in particular an LTE radio network.
[0009] This object and others are obtained by the method and device as set out in the appended claims.
[0010] In accordance with some embodiments a network node is provided to be operatively connected to a set of radio base stations of the radio network and to retrieving a neighbor list from each radio base station is said set of radio base stations. Based on said list of neighbors it is determined if a pair of radio base stations lack a connection between them, and upon determining that a connection between two radio base stations is lacking a connection between said pair of radio base stations is set up.
[0011] In accordance with some embodiments it is further determined from the neighbor list is there is an existing connection between two radio base stations that is not used, and upon determination that a connection between two radio base stations is unused the connection between that pair of radio base stations can be released. In one embodiment the connection is only released if a timer associated with said pair of radio base stations has expired. The timer can be set when no timer exists for said pair of radio base stations and it is determined that there is an existing connection between two radio base stations that is not used.
[0012] The radio network can typically be a Long term evolution, LTE, network where the connection between the radio base stations is provided over the X2interface of the LTE radio network. However, the radio network can be of other types. For example the radio network can be a heterogeneous network or a radio network comprising small cells.
[0013] In accordance with embodiments described herein a central node is provided. The central node can be implemented as an external standalone server or embedded with an MME element. The central node is configured to dynamically compute a list of eNBs which needs to be connected in the current and an upcoming timeframe while handling the distributed L3 connectivity setup of the network elements backhauling the eNBs connections. Using the central node as described herein this can be performed in one unit.
[0014] Thus a single L3 configuration location is provided in one node instead of in multiple locations in the mobile backhaul network. Hereby an automatic and dynamic detection of connectivity needs depending on traffic patterns can be provided. Also a meshed L3 connectivity services without the need to deploy L3 Network elements in Mobile Backhaul is enabled. The provision of a central node for managing eNB connections also makes it possible to continuously use a shortest path connection between eNBs, saving backhaul capacity and minimizing delay.
[0015] The disclosure also extends to a node for use in a cellular radio system adapted to perform the methods as described herein. The node can be provided with a controller/controller circuitry for performing the above processes. The controller(s) can be implemented using suitable hardware and or software. The hardware can comprise one or many processors that can be arranged to execute software stored in a readable storage media. The processor(s) can be implemented by a single dedicated processor, by a single shared processor, or by a plurality of individual processors, some of which may be shared or distributed. Moreover, a processor or may include, without limitation, digital signal processor (DSP) hardware, ASIC hardware, read only memory (ROM), random access memory (RAM), and/or other storage media.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The present invention will now be described in more detail by way of non-limiting examples and with reference to the accompanying drawings, in which:
[0017] FIG. 1 is a general view of a cellular radio network,
[0018] FIG. 2 is a general view of a cellular radio network comprising a central node for managing connections between radio base stations in the radio network,
[0019] FIG. 3 is a flowchart illustrating some steps performed when setting up a connection between two radio base stations.
[0020] FIG. 4 is a flowchart illustrating some steps performed when disconnecting a connection between two radio base stations, and
[0021] FIG. 5 illustrates a central node for managing connections between radio base stations in the radio network.
DETAILED DESCRIPTION
[0022] In FIG. 1 a general view of a cellular radio system is depicted. The system can for example be an LTE radio system. The system comprises a number of radio base stations 15 a , 15 b , 15 c , termed eNBs. A mobile station 18 , termed User Equipment UE, that is in a geographical area 19 covered by an eNB can connect to the eNB over an air-interface providing a downlink 12 and uplink 13 . The eNBs can be connected to each other via an X2 interface 16 . Also each eNB is connected to an S-GW/MME 10 a , 10 b via an S1 interface 17 .
[0023] In a network such as the network schematically illustrated in FIG. 1 , the X2 topology can be established either through configuration from e.g. a management system, or in combination with learning from performed handovers as UEs move in the network. The network will then over time learn which eNB neighbor relations that are applicable.
[0024] To enhance performance in a cellular network such as the network depicted in FIG. 1 , a central node for managing X2 connections can be provided. The central node can be configured to perform the following actions:
Fetch lists of neighbor eNBs associated to each eNBs. Check if a connection between the listed neighbors is already available. If a connection is not available, set up a connection using an OpenFlow configuration protocol.
[0028] In FIG. 2 such a central node 20 is depicted in a network as set out in FIG. 1 . The central node can be configured as a stand alone device or it can be embedded/co-located with another node such as an MME device in the LTE network.
[0029] In FIG. 3 a flow chart illustrating some steps that can be performed in a central node are depicted. First in a step S 1 , the central node fetches a list of neighbors eNBs associated to an eNB from the respective eNBs. The lists are fetched in accordance with some scheme. For example the lists can be fetched at some suitable time intervals. The time interval can be configurable, that can be set by an operator. In some instances the time interval can range from from a second to 30 minutes.
[0030] Next in a step S 2 the received list is checked to see if there is there is a need for a new connection between two eNBs. If the check in step S 2 reveals that there is a need for a new connection between two eNBs a flag can in accordance with some embodiments be set to indicate this by setting the flag to ‘1’ and the number of UEs is set to one ‘1’. Also a new connection is set up between the two eNBs where a connection is determined to be needed in step S 2 . This set up is performed in a step S 3 . The set up in step S 3 can be performed using the OpenFlow protocol such that the SDN controller will be triggered to configure the new path with OpenFlow. If, on the other hand there is no new neighbor pair in the list retrieved in step S 1 as determined in step S 2 , the number of UEs is updated. By keeping a record on the number of UEs it is possible to determine when there are no more UEs that require a particular connection between two eNBs. Thus by keeping a record over the UEs it is possible to delete a connection between two eNBs when the connection is no longer needed.
[0031] In FIG. 4 another flowchart illustrating some steps performed in that can be performed in a central node are depicted. The timer functionality in the below exemplary embodiment is optional. The timer can be useful to reduce the number of connection setups and releases. First, in a step S 11 , the central node fetches a list of neighbors eNBs associated to an eNB.
[0032] Next, in a step S 12 , the received list is checked to see if there is there is an unused connection between two eNBs. If the check in step S 12 reveals that there is an unused connection between two eNBs the number of UEs is set to zero ‘0’ in a step S 13 . Next in a step S 14 it is checked if a timer has expired. The step S 14 is optional. If the timer has expired in step S 14 a flag can be set to indicate this by setting a corresponding flag to ‘0’ and releasing the connection between the eNBs determined to be unused in step S 12 . The release of the connection and flag setting can be performed in a step S 15 .
[0033] If a timer is employed and the timer has not expired in step S 14 , it can be checked in a step S 16 if the timer is set. If the timer is set the procedure continues, but otherwise the timer is set in a step S 17 .
[0034] If in step S 12 it is reveals that a particular connection between two eNBs is not unused, the number of UEs is updated in a step S 18 . Also, as an optional procedure it can be checked is a timer is set in a step S 19 . If the timer is set the timer is deleted in a step S 20 else the procedure proceeds.
[0035] The following table shows an example of a data structure maintained by a central node to keep track of the status and the utilization of the connections and referred to in FIG. 3 and FIG. 4 . The table already includes the complete set of entry for a full mesh topology. The “active” flag determines which connection is currently setup, while the “number of UE” reports how many UEs have such connection currently in their list or in alternative what is the status of the utilization of the channel.
[0036] The frequency with which the controller fetches the neighbor list from eNBs determines the grade of dynamicity by which the connections can be updated. Tradeoffs considerations between the amount of info to be processed by the controller and the required system reactivity can be done.
[0037] In accordance with some embodiments the lists are fetched more frequently from some parts of the network than from other parts of the network. For example the lists can be fetched more frequently from the part of the network determined to be more dynamic and fetching is performed more seldom from a part of the network determined to be more stable. Also the check if a connection between two eNBs is unused can be performed with lower frequency than a check if a new connection between two eNBs is required. Check only periodically if the existing connections are still needed by fetching the lists from eNBs.
[0000]
TABLE 1
From
To
Num. of UEs/utilization
Active
Timer
1
2
3
1
N/A
1
3
5
1
N/A
1
4
0
1
10
2
3
0
0
0
2
4
7
1
N/A
3
4
10
1
N/A
[0038] A corresponding mechanism can be used for optimizing resources in small cells/HetNets (heterogeneous networks). The method as described above can thus also be applied for heterogeneous networks and for small cells.
[0039] In FIG. 5 a device for implementing the central node 20 is depicted. As set out above the central node 20 can be implemented as a stand alone server or it can be embedded in an existing node such as an MME. The central node comprises a processor 21 , a memory 23 , and a network interface 22 for connection to other nodes of the network that the central node is in communication with such as the eNBs. In particular embodiments, some or all of the functionality described above as being provided by a central node, is provided by the processor 21 executing instructions stored on a computer-readable medium, such as the memory 23 . The hardware of the central node 20 can comprise one or many processors 21 that can be arranged to execute software stored in a readable storage media such as the memory 23 . The processor(s) can be implemented by a single dedicated processor, by a single shared processor, or by a plurality of individual processors, some of which may be shared or distributed. Moreover, a processor or may include, without limitation, digital signal processor (DSP) hardware, ASIC hardware, read only memory (ROM), random access memory (RAM), and/or other storage media. | In a radio system a network node is provided to be operatively connected to a set of radio base stations of the radio network and to retrieving a neighbor list from each radio base station in said set of radio base stations. Based on said list of neighbors it is determined if a pair of radio base stations lack a connection between them, and upon determining that a connection between two radio base stations is lacking a connection between said pair of radio base stations is set up. | 7 |
CROSS-REFERENCE TO RELATED APPLICATION
This is a continuation-in-part of my copending application Ser. No. 570,189, filed Apr. 21, 1975.
BACKGROUND OF THE INVENTION
This invention relates to the prevention of access of bacteria and other contaminants to an area where medical operations are carried out.
In my copending application I have disclosed that bacteria and other contaminants can be denied access to such an area by directing a stream of sterile gas over the area to act as gas curtain which prevents access of such contaminants to the area.
That arrangement has been found to be largely satisfactory in its intended effect. However, I have observed that there are some ways in which contaminants may still penetrate the gas curtain.
In particular, in the area where the stream of sterile gas issues from the outlet opening that is provided to direct it across the operating area, there is the danger that the sterile gas stream aspirates contaminants from the ambient space into its boundary layer from where they can make their way to the protected operating area. Contaminants may also enter from the area below the top of the operating table, making their way around the edge of the operating table top and then being picked up by gas eddies to be carried to the operating area.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the invention to overcome these problems.
More particularly, it is an object of the invention to protect the operating area still more reliably against contaminants.
A particular object of the invention is to protect the stream of sterile gas against penetrations by such contaminants.
Further objects are to provide a novel method and arrangement for so protecting the stream of sterile gas.
In keeping with these objects, and with others which will become apparent hereafter, one feature of the invention resides in a novel arrangement of the type in question which, briefly stated, comprises first means for producing a stream of sterile gas, second means for directing the stream tangentially over the area to form a gas curtain which prevents access of contaminants to the area, and third means for preventing ambient contaminants from penetrating into the stream of sterile gas.
The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic illustration, showing an operating table and an arrangement according to the present invention;
FIG. 2 is a top plan view of parts of the novel arrangement;
FIG. 3 shows these parts in a front view;
FIG. 4 is a view similar to FIG. 3, but illustrating a field of flow;
FIG. 5 is a longitudinal section through an element of the invention;
FIG. 6 is a side view of the element in FIG. 5; and
FIG. 7 is a perspective view of the element in FIG. 6.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The invention is illustrated in FIGS. 1-7 by way of exemplary embodiments. The novel arrangement will be seen in FIGS. 1-3 to have a discharge element or head 1 and an aspirating or suction head 2. A stream 3 of sterile gas, e.g. air, is discharged from head 1 in direction towards the head 2 which aspirates it for withdrawal via conduits 4.
The arrangement is for use with an operating table 6 on the top 5 of which medical operations are to be carried out, so that the area 7 above the top 5 must be protected against contaminants, such as bacteria. Heads 1 and 2 may be mounted on adjustable joints (e.g. ball-joints) so that they can be adjusted relative to one another in such a manner that the protective gas stream 3 travels exactly above the area 7.
Depending upon the particular operation to be carried out, the size and shape of the area 7 to be protected may differ from case to case. To allow for such variations, the heads 1 and 2 are mounted on their supports 8 in such a manner that they can be raised and lowered. Head 1 may be concavely curved, in accordance with the contours of a patient resting on the table top 5. It could also be made flexible, so as to accommodate it to different contours.
This arrangement discharges the sterile gas stream 3 which flows above the area 7 in a tunnel-shaped or curtain-like manner and prevents access of contaminants to the area 7. The gas stream 3 may also be so directed that it flows over the edges of the operating wound, e.g. incision, in such a manner that these edges are prevented from drying out. This effect may be obtained, e.g. by having an upper part of the stream travel at higher speed than a lower part of the stream. If the stream 3 is concavely curved in cross-section, it can be used for intensive care applications where a patient must be protected against contaminants. The heads 1 and 2 are so adjusted that the stream 3 travels tangentially over the area 7.
The features set forth above, and the manner in which the sterile gas stream 3 is produced, are essentially set forth in my aforementioned copending application.
I have now found that it is important to protect the gas stream 3 itself against penetration by contaminants which could otherwise make their way through the stream 3 to the area 7.
To achieve this, I surround the outlet opening 9 for stream 3 with ports 10, preferably of slot-shaped configuration. The ports 10 could also have other shapes, e.g. be in form of laterally adjacent bores which are distributed over the boundary wall 11 of opening 9. These ports 10 extend substantially parallel to the flow-direction of stream 3 and are preferably connected with a source of constant suction.
As a result of such suction, a protective air stream 12 is generated which flows towards the ports 10, in countercurrent to the stream 3. Air stream 12, whose length depends upon the degree of suction in ports 10, extends partly along the stream 3 and tubularly surrounds the opening 9. Any bacteria or other contaminants which tend to be drawn from the ambient space into the stream 3 by the velocity of the same, are removed from the stream 3 due to the fact that the surrounding stream 12 draws off the boundary layer of stream 3 and thus carries all such contaminants into the ports 10.
FIG. 4 shows that the ports 10 can be combined to form a channel-shaped port which annularly surrounds the opening 9. Such a construction is best suited if there are no obstructing elements present in the opening 9. The latter may, incidentally, be of different shapes, e.g. rectangular, horse-shoe shaped or the like, and depending upon the particular requirements for area 7 the ports 10 may surround the opening 9, be located only at its lateral sides, only at its top and bottom, or be otherwise distributed.
Instead of connecting the ports 10 with a source of suction, they could also be connected with a source of pressure which is adequate to impart to the air stream 12 a flow speed greater than that of stream 3. The flow of stream 12 would then be concurrent with that of stream 3. It is, however, always important that there be relative movement between the streams 3 and 12.
The entry of contaminants from the area below and laterally of the operating table 6 must also be prevented. For this purpose, tubes 13 are arranged which extend adjacent and substantially parallel to the lateral edges of the table top 5 and preferably extend over the entire length of these lateral edges. Tubes 13 have openings 14, preferably in form of slots extending parallel to the lateral edges. The tubes 13 may, but need not be, arranged upwardly of the table top 5. They could also be recessed into the same, be located beneath the level of the top 5, or arranged laterally thereof. They may also be located outside or inside of the head 1.
Tubes 13 are connected with a source of suction, preferably a source of constant suction, so that lateral eddies formed in the stream 3 are aspirated into the slots 14. The latter could also be facing towards the area 7, if desired. This aspiration takes place in form of gas streams 15 which carry along any contaminated air from the lateral regions of stream 3 and from the lateral edges of table top 5, as well as from the area beneath the table top 5. If desired, the tubes 13 could be communicated with the passages which in head 1 connect the ports 10 with the suction source, especially if lateral portions 25 of head 1 extend to the immediate vicinity of the table top 5.
To protect gas stream 3 against contaminants that might enter it from the area below table top 5, the head 1 is provided in the region of its lower end 16, near the corners of top 5, with downwardly facing openings 17. These are preferably provided at the underside of portions 25 and connected with a source of gas under constant pressure, so that a stream 18 issues from them. This stream is directed into the area below table top 5 where it entrains any contaminants and carries them away from the top 5. Openings 17 may face vertically downwardly, or at an angle. The area between top 5 and openings 17 is provided with a baffle 19 which shields the area 7 relative to the area forwardly of head 1. However, the baffle 19 could be omitted, if the openings 17 are arranged over the entire lower end 16 of head 1 so as to produce a fan-shaped air curtain. Depending upon the size and shape of the area 7, the openings 17 could be connected with a suction source instead of a pressure source, so that a stream 18 is produced which flows into the openings 17, rather than out of them, but of course serves the same purpose.
If desired, the head 2 may also be provided at its lower end 20 with downwardly directed openings 21. These are preferably connected to a source of gas under pressure and advantageously are spaced over the entire lower end 20. They discharge a fan-shaped gas stream 22 which prevents any contaminants below table top 5 from rising upwardly along the edge of top 5 which is located adjacent head 2. Conversely, the openings 21 could, of course, be connected to a source of suction. This would cause a flow of the gas stream 22 into the openings 21, but the purpose and end effect would be the same.
Heads 1 and 2 may be mounted on table top 5 turnably and height-adjustably, by means of supports 8. However, they could be mounted on supports that are separate and spaced from the table 5, if desired. The area between table top 5 and the lower end 16 of the head 1 is protected against entry of contaminants by the baffle 19 which is preferably of flexible material, e.g. a synthetic plastic material such as PVC, PUT or the like. If the baffle 19 is omitted, then this area is shielded by the downwardly directed, fan-shaped gas stream 18.
The boundary-layer removing gas stream which protects the stream 3 against contaminants may be made up of several partial or individual streams, as described. This has the advantage of completely protecting the lateral regions of stream 3 which are particularly susceptable to the entry of contaminants. However, a single, essentially tubular protective stream may also be utilized which surrounds the stream 3 completely.
It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of applications differing from the types described above.
While the invention has been illustrated and described as embodied in an arrangement for protecting an operating area, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.
Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention. | An arrangement for preventing access of bacteria and other contaminants to an area in which medical operations are carried out, having first instrumentalities for producing a stream of sterile gas, second instrumentalities for directing the stream tangentially over the area to form a gas curtain which prevents access of contaminants to the area, and third instrumentalities for preventing ambient contaminants from penetrating into the stream of sterile gas. | 5 |
BACKGROUND
[0001] 1. Technical Field
[0002] The present invention generally relates to a remote supporting apparatus that performs an operation for projecting an image on a predetermined projection region in cooperation with another device, a remote supporting system that includes the remote supporting apparatus, and a remote supporting method to be utilized in the remote supporting apparatus.
[0003] 2. Related Art
[0004] During presentations, images of materials (slides) prepared with presentation software in personal computers (PCs) are often projected on screens by projectors.
[0005] In such image processing, an image sent from a remote place is projected with a projector, an image of the screen having the image projected thereon is recorded, and the image information obtained through the recording is transmitted to a remote place. Alternatively, a picture drawn by a user with a pen or the like is displayed on an electronic whiteboard at own site, and a picture that is originally drawn on an electronic whiteboard is also displayed at another site and is received and converted by a communication controller on the electronic whiteboard at the own site.
SUMMARY
[0006] An aspect of the present invention provides a remote supporting apparatus including: a first receiving unit that receives information about a first annotation image from another device; a projecting unit that projects an image on a predetermined projection region in cooperation with the another device in accordance with the information about the first annotation image received from the first receiving unit; a recording unit that records an image of the projection region; a first transmitting unit that transmits image information about the recorded image obtained by the recording unit, as image information about an image to be displayed on the another device, to the another device; a second transmitting unit that transmits information about a second annotation image to be projected on a projection region at a site at which the another device is placed; a second receiving unit that receives information about a recorded image obtained by recording an image of the projection region at the site at which the another device is placed, the information being received from the another device; and a displaying unit that displays an image in accordance with the information about the recorded image received by the second receiving unit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Embodiments of the present invention will be described in detail based on the following figures, wherein:
[0008] FIG. 1 illustrates the basic structures of remote supporting apparatuses that constitute a remote supporting system;
[0009] FIG. 2 illustrates the structure of the remote supporting system;
[0010] FIG. 3 is a flowchart showing an operation to be performed by each server system;
[0011] FIG. 4 is a flowchart showing an operation to be performed by each client system;
[0012] FIG. 5 illustrates another example structure of a remote supporting apparatus; and
[0013] FIG. 6 illustrates another example structure of a remote supporting system.
DETAILED DESCRIPTION
[0014] A description will now be given, with reference to the accompanying drawings, of exemplary embodiments of the present invention. FIG. 1 illustrates the structures of remote supporting apparatuses that form a remote supporting system. In FIG. 1 , a server system 110 as a remote supporting apparatus and a whiteboard 160 are placed at site A, and a client system 200 as a remote supporting apparatus is placed at site B.
[0015] The server system 110 at the site A includes a drawing server 112 , a video server 114 , a projector 116 , a video camera 118 , and a half mirror 120 . Meanwhile, a client system 240 at the site B includes a monitor 242 . The drawing server 112 and the video server 114 in the server system 110 at the site A are communicably connected to the client system 240 at the site B with the Internet 400 .
[0016] In this exemplary embodiment, the same client system as the client system 240 at the site B is provided together with the server system 110 , so as to form a remote supporting apparatus at the site A. The same server system as the server system 110 at the site A is provided together with the client system 240 , so as to form a remote supporting apparatus at the site B. A whiteboard is also provided at the site B, thereby forming a remote supporting system.
[0017] FIG. 2 illustrates the structure of the remote supporting system. In the remote supporting system illustrated in FIG. 2 , the server system 110 and a client system 140 as a remote supporting apparatus, and the whiteboard 160 are set at the site A. The client system 140 includes a monitor 142 . Meanwhile, a server system 210 and the client system 240 as a remote supporting apparatus, and a whiteboard 260 are set at the site B. The server system 210 is formed with a drawing server 212 , a video server 214 , a projector 216 , a video camera 218 , and a half mirror 220 . The client system 140 at the site A is communicably connected to the drawing server 212 and the video server 214 in the server system 210 at the site B with the Internet 400 .
[0018] The server system 110 at the site A performs an operation for projecting an image at the site A in response to a request from the client system 240 at the site B. Likewise, the server system 210 at the site B performs an operation for projecting an image at the site B in response to a request from the client system 140 at the site A. The operations are described below in greater details.
[0019] In accordance with an operation instruction of the user at the site B, the client system 240 at the site B generates a drawing command as an instruction for projecting an annotation image such as an explanatory note, and information about the annotation image. The client system 240 then transmits the drawing command and the information to the drawing server 112 in the server system 110 at the site A via the Internet 400 .
[0020] In response to the received drawing command, the drawing server 112 outputs the information about the annotation image together with the drawing command to the projector 116 . If there is image information that has already been held by the drawing server 112 , the drawing server 112 outputs the image information to the projector 116 . The projector 116 projects an image in accordance with the input image information, onto the whiteboard 160 via the half mirror 120 .
[0021] An image is projected on the white board 160 by the projector 116 , and characters or the likes are written on the whiteboard 160 by the user of the site A. The video camera 118 records, through the half mirror 120 , the whiteboard 160 having an image projected thereon and characters or the likes written thereon. The video camera 118 has various settings for panning, tilting, zooming, and the likes, so that the video camera 118 has the same field angle and the same optical axis as the projector 116 . The image information obtained through the recording is output to the video server 114 . The video server 114 transmits the input image information to the client system 240 at the site B via the Internet 400 .
[0022] The client system 240 at the site B displays the received image information on the monitor 242 . Accordingly, the user of the site B can recognize the image on the whiteboard 160 at the site A.
[0023] The same operation as above is performed between the client system 140 at the site A and the server system 210 at the site B. In accordance with an operation instruction from the user of the site A, the client system 140 at the site A generates a drawing command as an instruction for projecting an annotation image, and information about the annotation image. The client system 140 then transmits the drawing command and the information to the drawing server 212 in the server system 210 at the site B via the Internet 400 .
[0024] In response to the received drawing command, the drawing server 212 outputs the information about the annotation image together with the drawing command to the projector 216 . If there is image information that has already been held by the drawing server 212 , the drawing server 212 outputs the image information to the projector 216 . The projector 216 projects an image in accordance with the input image information, onto the whiteboard 260 via the half mirror 220 .
[0025] An image is projected on the whiteboard 260 by the projector 216 , and characters or the likes are written on the whiteboard 260 by the user of the site B. The video camera 218 records, through the half mirror 220 , the whiteboard 260 having an image projected thereon and characters or the likes written thereon. The video server 214 transmits the input image information to the client system 140 at the site A via the Internet 400 .
[0026] The client system 140 at the site A displays the received image information on the monitor 142 . Accordingly, the user of the site A can recognize the image on the whiteboard 260 at the site B.
[0027] In the following, the operations of the server system 110 at the site A and the client system 240 at the site B are described, with reference to flowcharts.
[0028] FIG. 3 is a flowchart showing the operation to be performed by the server system 110 at the site A. The drawing server 112 in the server system 110 at the site A outputs already held image information to the projector 116 . The projector 116 projects the image in accordance with the input image information (the initial image), onto the whiteboard 160 through the half mirror 120 (S 101 ).
[0029] The video camera 118 starts recording the whiteboard 160 (S 102 ). The image information through the recording (the information about the recorded image) is output to the video server 114 . The video server 114 starts transmitting the input image information to the client system 240 at the site B (S 103 ). After that, the video camera 118 continues recording the whiteboard 160 , and the video server 114 keeps transmitting image information to the client system 240 at the site B every time image information is input.
[0030] The drawing server 112 determines whether it has received a drawing command from the client system 240 at the site B (S 104 ) If having received a drawing command, the drawing server 112 outputs the information about the annotation image attached to the drawing command to the projector 116 in accordance with the drawing command. The projector 116 projects the image in accordance with the input information about the annotation image, onto the whiteboard 160 via the half mirror 120 (S 105 ). As a result, the initial image and an image such as an explanatory note in accordance with the information about the annotation image attached to the drawing command from the client system 240 at the site B are projected onto the whiteboard 160 . In the image recorded by the video camera 118 , problems such as uncolored portions might be caused in the image formed in accordance with the information about the annotation image from the client system 240 at the site B. With such problems being taken into consideration, the video server 114 may generate image information about a combined image formed by overlapping the image formed in accordance with the information about the annotation image from the client system 240 at the site B on the position of the image formed in accordance with the information about the annotation image from the client system 240 at the site B in the image recorded by the video camera 118 . The video server 114 may transmit the image information to the client system 240 at the site B.
[0031] After the image projection in step S 105 , or if the drawing server 112 determines that it has not received a drawing command yet in step S 104 , the server system 110 determines whether the user of the site A has issued an instruction to end the operation (S 106 ). If there is an instruction to end the operation, the operation comes to an end. If there is not such an instruction, the procedure for determining whether the drawing server 112 has received a drawing command (S 104 ) and the procedures thereafter are repeated.
[0032] FIG. 4 is a flowchart showing the operation to be performed by the client system 240 at the site B. In accordance with an operation instruction from the user of the site B, the client system 240 generates the drawing command for projecting an annotation image such as an explanatory note on the whiteboard 160 at the site A or the whiteboard 260 at the site B (S 201 ).
[0033] The client system 240 then performs an image drawing process, and generates the information about the annotation image to be projected onto the whiteboard 160 at the site A or the whiteboard 260 at the site B (S 202 ). The client system 240 determines whether the destination of the drawing command is the server system 210 that is also located at the site B (S 203 ). For example, the user of the site B designates the destination through the operation instruction for the generation of the drawing command, and the client system 240 detects the destination from the operation instruction.
[0034] In a case where the destination of the drawing command is not the server system 210 also located at the site B, the client system 240 adds the annotation image information generated in step S 202 to the drawing command, and transmits the drawing command to the drawing server 112 in the server system 110 at the site A (S 204 ) As a result, the server system 110 carries out the procedure of step S 105 of FIG. 3 .
[0035] In a case where the destination of the drawing command is the server system 210 also located at the site B, the client system 240 adds the annotation image information generated in step S 202 to the drawing command, and transmits the drawing command to the server system 210 (S 205 ). In this case, the drawing server 212 in the server system 210 outputs the annotation image information attached to the received drawing command to the projector 216 , and the projector 216 projects the image in accordance with the annotation image information onto the whiteboard 260 .
[0036] After the transmission of the drawing command in step S 204 or S 205 , the client system 240 determines whether there is an instruction to end the operation from the user of the site B (S 206 ). If there is an instruction to end the operation, the operation comes to an end. If there is not an operation to end the operation, the procedure for generating a drawing command (S 201 ) and the procedures thereafter are repeated.
[0037] The server system 210 at the site B performs the same operation as that illustrated in FIG. 3 , and the client system 140 at the site A performs as same operation as that illustrated in FIG. 4 .
[0038] As described above, in the remote supporting system, an image in accordance with annotation image information from the client system 240 at the site B is displayed on the whiteboard 160 at the site A. Likewise, an image in accordance with annotation image information from the client system 140 at the site A is displayed on the whiteboard 260 at the site B. A recorded image of the whiteboard 260 at the site B is displayed on the monitor 142 at the site A, and a recorded image of the whiteboard 160 at the site A is displayed on the monitor 242 at the site B. Accordingly, the whiteboard as the projection region at each site is used as a work area, so that cooperative operations can be performed between the sites, and communications become easier between users.
[0039] The present invention is not limited to the above-described exemplary embodiment, but various changes may be made to it. FIG. 5 illustrates another example structure of the remote supporting apparatus at the site A. In FIG. 5 , a server system 110 as a remote supporting apparatus, a client system 170 for monitoring own site, a client system 180 for another site, and a whiteboard 160 are placed at the site A. The same structure may be employed at the site B.
[0040] The client system 180 for another site includes a monitor 182 . The client system 180 for another site receives image information obtained by recording an image of the whiteboard 260 , and displays the image in accordance with the image information on the monitor 182 .
[0041] The user of the site A can issue such an operation instruction as to designate a part of the image displayed on the monitor 182 to be displayed on the whiteboard 160 . If such an instruction is issued, the client system 180 for another site selects the designated part of the image as a copy area 183 , and transmits the image information about the copy area 183 to the client system 170 for monitoring own site.
[0042] Upon receipt of the image information about the copy area 183 , the client system 170 for monitoring own site generates image information about a combined image of an image in accordance with the image information and an image in accordance with already held image information. The client system 170 for monitoring own site also displays the combined image on a monitor 172 , and transmits the image information about the copy area 183 to the server system 110 .
[0043] The drawing server 112 in the server system 110 outputs the received image information about the copy area 183 to the projector 116 . The projector 116 projects the combined image about the image information on the whiteboard 160 .
[0044] In this manner, at the site A, a part of the image in accordance with the image information obtained by recording an image of the whiteboard 260 at the site B is selected in accordance with an operation instruction from the user of the site A, and the selected part of the image is projected on the whiteboard 160 .
[0045] In the above-described exemplary embodiment, remote supporting apparatuses are placed at the two sites A and B in a remote supporting system. However, the present invention may be applied to a remote supporting system having remote supporting apparatuses placed at three or more sites. FIG. 6 illustrates an example case where remote supporting apparatuses are placed at three sites A, B, and C. At the site A, a server system 110 as a remote supporting apparatus and client systems 140 - 1 and 140 - 2 are placed. At the site B, a server system 210 as a remote supporting apparatus and client systems 240 - 1 and 240 - 2 are placed. At the site C, a server system 310 as a remote supporting apparatus and client systems 340 - 1 and 340 - 2 are placed.
[0046] In this imaging system, the server system 110 at the site A is communicably connected to the client system 240 - 1 at the site B and the client system 340 - 2 at the site C via the Internet 400 . In response to each request from the client systems 240 - 1 and 340 - 2 , the server system 110 at the site A performs an image projecting operation at the site A. Likewise, the server system 210 at the site B is communicably connected to the client system 140 - 1 at the site A and the client system 340 - 1 at the site C via the Internet 400 . In response to each request from the client systems 140 - 1 and 340 - 1 , the server system 210 at the site B performs an image projecting operation at the site B. The server system 310 at the site C is communicably connected to the client system 140 - 2 at the site A and the client system 240 - 2 at the site B via the Internet 400 . In response to each request from the client systems 140 - 2 and 240 - 2 , the server system 310 at the site C performs an image projecting operation at the site C.
[0047] As described so far, the remote supporting apparatuses, the remote supporting systems, and the remote supporting method in accordance with the present invention enable smooth communications between users at different sites, and are suitable for remote supporting apparatuses.
[0048] The foregoing description of the exemplary embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The exemplary embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents. | A remote supporting apparatus including a first receiving unit that receives information about a first annotation image from another device, a projecting unit that projects an image on a predetermined projection region in cooperation with the another device in accordance with the information about the first annotation image received from the first receiving unit, a recording unit that records an image of the projection region, a first transmitting unit, a second transmitting unit, a second receiving unit, and a displaying unit that displays an image in accordance with the information about the recorded image received by the second receiving unit. | 8 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional Patent Application 61/781,086, filed Mar. 14, 2013, which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates generally to controlling the properties of elastic structures, such as elastic hinges in microelectromechanical systems (MEMS).
BACKGROUND
[0003] In microelectromechanical systems (MEMS), rotating hinges may be produced by etching a silicon substrate to form long, narrow beams. In the context of MEMS, as well as in the present description and in the claims, a “long, narrow” element has transverse dimensions (i.e., dimensions measured transversely to the longitudinal axis of the element) that are less than one tenth of the length of the beam. Such hinges are used, inter alia, in scanning micromirrors, such as those described, for example, in U.S. Pat. No. 7,952,781, whose disclosure is incorporated herein by reference. This patent describes a method of scanning a light beam and a method of manufacturing, which can be incorporated in a scanning device.
[0004] As another example, U.S. Patent Application Publication 2012/0236379 describes a LADAR system that uses MEMS scanning. A scanning mirror includes a substrate that is patterned to include a mirror area, a frame around the mirror area, and a base around the frame. A set of actuators operate to rotate the mirror area about a first axis relative to the frame, and a second set of actuators rotate the frame about a second axis relative to the base.
[0005] As yet another example, U.S. Patent Application Publication 2013/0207970, whose disclosure is incorporated herein by reference, describes a micromirror that is produced by suitably etching a semiconductor substrate to separate the micromirror from a support, and to separate the support from the remaining substrate. After etching, the micromirror (to which a suitable reflective coating is applied) is able to rotate in the Y-direction relative to the support on spindles, while the support rotates in the X-direction relative to the substrate on further spindles. (Such a support is also referred to as a gimbal, and the spindles are a type of hinges.) The micromirror and support are mounted on a pair of rotors, which are suspended in respective air gaps of magnetic cores. An electrical current driven through coils wound on the cores generates a magnetic field in the air gaps, which interacts with the magnetization of the rotors so as to cause the rotors to rotate or otherwise move within the air gaps.
[0006] As an alternative to the sorts of etched silicon hinges described above, Fujita et al. describe hinges made from polymeric material, in “Dual-Axis MEMS Mirror for Large Deflection-Angle Using SU-8 Soft Torsion Beam,” Sensors and Actuators A 121 (2005), pages 16-21. This article describes a MEMS galvano-mirror with a double gimbal structure having soft torsion beams made of the photosensitive epoxy resin SU-8. This approach is said to give large deflection angles (over ±40°) for small driving power.
SUMMARY
[0007] Embodiments of the present invention that are described hereinbelow provide elastic micro-devices and methods for production of such devices.
[0008] There is therefore provided, in accordance with an embodiment of the present invention, a mechanical device, which includes a long, narrow element made of a rigid, elastic material, and a rigid frame configured to anchor at least one end of the element, which is attached to the frame, and to define a gap running longitudinally along the element between the beam and the frame, so that the element is free to move within the gap. A solid filler material, different from the rigid, elastic material, fills at least a part of the gap between the element and the frame so as to permit a first mode of movement of the element within the gap while inhibiting a different, second mode of movement.
[0009] In some embodiments, the long, narrow element includes a beam, which is configured as a hinge so as to rotate about a longitudinal axis of the beam relative to the frame, while the filler material inhibits transverse deformation of the beam. In one embodiment, the beam includes an anchor, broader than the hinge, which connects the hinge to the frame. Additionally or alternatively, the device includes a mirror, wherein a first end of the beam is attached to the frame, while a second end of the beam is attached to the mirror, so that the mirror rotates on the hinge relative to the frame.
[0010] In another embodiment, the device includes a sensor, which is configured to sense a relative rotation between the frame and the hinge. The sensor may be configured to sense an acceleration of the device responsively to the relative rotation. Alternatively, the device includes an energy-harvesting assembly, coupled to harvest energy generated by a relative rotation between the frame and the hinge.
[0011] In another embodiment, the long, narrow element is configured as a spiral spring.
[0012] Typically, the frame and the long, narrow element include parts of a semiconductor wafer, in which the gap is etched between the frame and the long, narrow element.
[0013] In some embodiments, the filler material has a Poisson ratio at least 50% higher than that of the long, narrow element, and a Young's modulus at least 50% less than that of the long, narrow element. Typically, the filler material is selected from a group of materials consisting of polymers and adhesives.
[0014] In an alternative embodiment, the filler material includes an array of nano-tubes.
[0015] There is also provided, in accordance with an embodiment of the present invention, a method for producing a mechanical device. The method includes forming, from a rigid, elastic material, a long, narrow element having at least one end attached to a rigid frame with a gap running longitudinally along the element between the beam and the frame, so that the element is free to move within the gap. At least a part the gap is filled with a solid filler material, different from the rigid, elastic material, so as to permit a first mode of movement of the element within the gap while inhibiting a different, second mode of movement.
[0016] In disclosed embodiments, the rigid, elastic material includes a semiconductor wafer, and forming the long, narrow element includes etching the semiconductor wafer to define both the frame and the long, narrow element, with the gap therebetween. In one embodiment, filling at least a part of the gap includes, after etching the gap, coating the wafer with the filler material, so that filler material fills the gap, and then removing an excess of the filler material outside the gap.
[0017] The present invention will be more fully understood from the following detailed description of the embodiments thereof, taken together with the drawings in which:
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a schematic, pictorial illustration of a MEMS scanning mirror assembly, in accordance with an embodiment of the present invention;
[0019] FIG. 2 is a schematic detail view of an elastic hinge, in accordance with an embodiment of the present invention;
[0020] FIG. 3A is a schematic, pictorial illustration of an elastic hinge under torsional deflection, in accordance with an embodiment of the present invention;
[0021] FIG. 3B is a schematic detail view of the elastic hinge of FIG. 3A , showing deformation of a filler material in the hinge due to torsional deflection of the hinge, in accordance with an embodiment of the present invention;
[0022] FIG. 4 is a schematic detail view of an elastic hinge, showing deformation of a filler material in the hinge due to in-plane defection, in accordance with an embodiment of the present invention;
[0023] FIG. 5 is a schematic detail view of an elastic hinge, showing deformation of a filler material in the hinge due to out-of-plane defection, in accordance with an embodiment of the present invention;
[0024] FIGS. 6A-6F are schematic sectional views through a semiconductor wafer at successive stages of a process of fabrication of an elastic hinge reinforced by a filler material, in accordance with an embodiment of the present invention;
[0025] FIG. 7 is a schematic side view of an inertial sensor, in accordance with an embodiment of the present invention;
[0026] FIG. 8 is a schematic side view of an energy harvesting device, in accordance with another embodiment of the present invention;
[0027] FIG. 9A is a schematic, pictorial illustration of a gyroscopic sensor, in accordance with yet another embodiment of the present invention;
[0028] FIG. 9B is a schematic detail view of an elastic hinge in the sensor of FIG. 9A , in accordance with an embodiment of the present invention;
[0029] FIG. 10 is a schematic detail view of an elastic hinge assembly, in accordance with an alternative embodiment of the present invention;
[0030] FIG. 11A is a schematic, pictorial view of an elastic hinge assembly, in accordance with a further embodiment of the present invention;
[0031] FIG. 11B is a schematic, pictorial illustration of the assembly of FIG. 11A under deflection, in accordance with an embodiment of the present invention; and
[0032] FIG. 12 is a schematic top view of a resonant radial spring, in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF EMBODIMENTS
Overview
[0033] Because of its high elasticity (Young's modulus E≅150 GPa), crystalline silicon can be used in MEMS devices to produce excellent hinges and other sorts of springs. Such hinges are well suited, for example, to support scanning mirrors, as described above. The torsional properties of the silicon hinge determine the range of motion and the resonant frequency of rotation of the mirror about the hinge axes.
[0034] In some applications, it is desirable to reduce the torsional stiffness (which is typically expressed in terms of the torsional spring constant K φ ) of the hinge, in order to increase the range of motion and/or to reduce the resonant frequency and the force required to drive the motion. The stiffness can be reduced by reducing the transverse dimensions (thickness) and/or increasing the length of the hinge. These same dimensional changes, however, will also reduce the resistance of the hinge to deflection (expressed in terms of the transverse spring constants K X and K Y , which scale as the inverse cube of the length and the cube of the thickness). As a result, the hinge will be more prone to breakage due to shock or vibration, for example.
[0035] Embodiments of the present invention that are described hereinbelow provide hybrid hinges and other elastic structures that have enhanced compliance (i.e., reduced stiffness) in a desired mode of motion, while maintaining strong resistance against other, undesired modes of motion. In the disclosed embodiments, these principles are applied in producing hinges characterized by both reduced torsional stiffness and robustness against transverse deflection. Such hinges thus have an increased angular range of motion and require less force for rotation than hinges of comparable transverse stiffness that are known in the art. Alternatively, the principles of the present invention may similarly be applied in producing springs with reduced resistance to stretching or desired modes of bending.
[0036] In the embodiments described below, a hybrid hinge comprises a long, narrow beam, which is made from a relatively rigid material of high elasticity and is contained within a rigid frame, which may be of the same or similar material as the beam. The end of the hinge is anchored to the frame, but one or more longitudinal gaps between the hinge and the frame enable the hinge to rotate about a longitudinal axis relative to the frame. These gaps are filled with a solid filler material, which permits the hinge to rotate freely, typically causing the torsional spring constant K φ to increase by no more than about 10-20% relative to the “bare” hinge, while at the same time increasing resistance to transverse deformation (as expressed by spring constants K X and K Y ) substantially—possibly tenfold or more.
[0037] The use of the filler material around the hinge provides added design flexibility, in that it permits the spring constant to be chosen independently of the transverse stiffness. In resonating systems, such as resonant scanning mirrors, the spring parameters may thus be chosen to give the desired resonant frequency and Q factor, without sacrificing mechanical robustness.
[0038] In some embodiments, the gaps between the hinge and the frame are filled with a soft solid material, having a Poisson ratio at least 50% higher than that of the hinge and frame, and possibly more than 100% higher. At the same time, Young's modulus for this soft material is at least 50% less than that of the hinge and frame, and may desirably be less than 10% of Young's modulus for the hinge and frame. For example, in a typical embodiment, the hinge and frame are etched from crystalline semiconductor material, such as silicon (Young's modulus 150 GPa and Poisson ratio 0.17), while the soft fill material comprises a polymer, such as polydimethylsiloxane (PDMS), SU-8 photoresist, RTV silicone, or other elastomer or epoxy (Young's modulus<5 GPa, Poisson ratio>0.45 and possibly≧0.49). Alternatively, the hinge and frame may be made from any other suitable elastic material, including metals such as steel or titanium, while the gaps may be filled with any suitable soft or porous material satisfying the above criteria.
[0039] In alternative embodiments, other types of filler materials may be used with similar effects. Such materials are not necessarily “soft” in the sense defined above. For example, highly-elastic carbon nano-tubes may be placed across the gaps to give the desired effects of rotational compliance and transverse stiffness.
MEMS Hinges
[0040] FIG. 1 is a schematic illustration of a MEMS scanning mirror assembly 20 , in accordance with an embodiment of the present invention. Although this figure shows, for the sake of simplicity, a mirror with a single scanning axis, the principles of this embodiment may similarly be applied to multi-axis gimbaled mirrors, such as those described in the above-mentioned U.S. Patent Application Publication 2013/0207970. The scanning axis is identified in the figure, for convenience, as the Z-axis, and the angle of rotation about the Z-axis is identified as φ.
[0041] Assembly 20 comprises a base 22 formed from a silicon wafer, which is etched to define a micromirror 24 . (The reflective coating of the micromirror is omitted for simplicity.) The micromirror is connected to the base by a pair of hinges 26 , comprising long, thin beams etched from the silicon substrate. These beams are connected at their inner ends to the micromirror and at their outer ends to the base. Wings 28 of micromirror 24 adjoin hinge 26 on both sides, thus defining a frame, with gaps between the frame and the hinge.
[0042] As explained earlier, in some applications it is desirable to reduce the transverse (X and Y) thickness of hinges 26 in order to allow the hinges to rotate about their longitudinal (Z) axes with large angular range and low torsional resistance, as expressed by the spring constant K. For example, hinges may be made 1-300 μm thick and 1-10000 μm long. The thinner the hinges, however, the lower will be their resistance (as expressed by K X and K Y ) to transverse deformation. Thus, even weak forces in the X- or Y-direction may cause hinge 26 to bend and, ultimately, to break.
[0043] FIG. 2 is a schematic detail view of hinge 26 , in accordance with an embodiment of the present invention. As illustrated in this figure, in order to alleviate the problem of the low resistance of the hinge to transverse deformation, the gaps between each hinge 26 and the adjoining wings 28 are filled with a suitable soft filler material 30 . (Alternatively, as noted earlier and as illustrated in FIG. 10 , other sorts of filler materials, not necessarily “soft,” may be configured for this purpose.) The filler material in this embodiment may comprise, for example, a suitable adhesive or other polymer, or a porous (foam) material, with high Poisson ratio and low Young's modulus, as explained above. Filler material 30 may be applied at wafer level during the fabrication process (as illustrated in FIG. 6 ), or it may be dispensed into the gaps in liquid form after fabrication. In the latter case, if the filler material comprises an adhesive, such as SU-8 epoxy, it can also be used to attach magnetic rotors to wings 28 , similar to the rotors described in the above-mentioned U.S. Patent Application Publication 2013/0207970.
[0044] Filler material 30 need not completely fill the gaps between hinge 26 and wings 28 . For example, it may be sufficient to fill only the part of the gap near the end of wing 28 in order hold the hinge in place against bending.
[0045] Filler material 30 acts as a sort of bearing within the gaps, in that it prevents, or at least drastically reduces, deformation of hinges 26 in the X- and Y-direction, while only minimally increasing torsional (φ) stiffness. Consequently, external forces in the transverse (X and Y) directions are largely absorbed by filler material 30 and give rise to only minimal bending stresses in hinge 26 . The hinge can thus be designed only for torsional stress, with a large range of rotation about the longitudinal (Z) axis. Filler material 30 damps shock and vibrations, thus enhancing the robustness and durability of assembly 20 .
[0046] FIGS. 3A and 3B illustrate the effect of torsional deflection (rotation about the Z-axis) on hinge 26 and on filler material 30 , respectively. FIG. 3A shows the rotational motion of wings 28 relative to frame 22 as it affects hinge 26 , while FIG. 3B shows the resulting deformation of filler material 30 . Rotation of hinge 26 stretches material 30 , particularly near its interfaces with the hinge, but material 30 offers only minimal resistance to this sort of stretching, which does not compress or otherwise change the volume of the material.
[0047] FIG. 4 illustrates the response of filler material 30 to deflection of hinge 26 in the plane of mirror 24 (i.e., deflection in the X-Z plane). The high Poisson ratio of material 30 causes deformation in response to the transverse (X-direction) force and resistance to bending of the hinge. Under typical operating conditions, with a hinge thickness of 1-300 μm and a filler material with a Poisson ratio of 4.9, the filler material increases the stiffness (resistance to transverse force) of the hinge in the X-direction by more than 1500%, relative to the stiffness of the hinge alone.
[0048] FIG. 5 illustrates the response of filler material 30 to deflection of hinge 26 out of the plane of mirror 24 (deflection in the Y-Z plane), due to a Y-direction force. The Y-direction movement causes a bulk deformation of the filler material, which consequently resists bending of the hinge. Under the conditions mentioned in the preceding paragraph, the stiffness of the hinge in the Y-direction is increased by about 1000%.
Fabrication Process
[0049] FIGS. 6A-6F are schematic sectional views through a wafer during a process of fabrication of a silicon hinge reinforced by a polymeric filler material, in accordance with an embodiment of the present invention. In this example, the hinge is fabricated in a silicon on insulator (SOI) wafer, in which a crystalline silicon layer 32 overlying an insulating substrate 34 ( FIG. 6A ), although other types of substrates may alternatively be used, as is known in the MEMS art.
[0050] To begin the process ( FIG. 6B ), gaps 36 surrounding the hinge are opened in silicon layer 32 , by deep reactive ion etching (DRIE) or another suitable process. Layer 32 is then overlaid with a polymer or porous filler 38 ( FIG. 6C ), which fills gaps 36 . The filler may comprise, for example, PDMS, which is applied by spin coating. Filler 38 is then etched down ( FIG. 6D ), thus removing the excess filler material and exposing layer 32 , while leaving filler material 40 in gaps 36 .
[0051] To form the MEMS structures, a photolithographic etching process is applied to layer 32 ( FIG. 6E ), creating spaces 42 between mirror 24 , base 22 and other moving elements, including the mirror hinges. To allow the mirror to move freely over a large range, substrate 34 may optionally be thinned away from the back side of the mirror and hinges ( FIG. 6F ). The wafer is then diced, and assembly of the scanner is completed as described, for example, in the documents cited in the Background section above.
Alternative Embodiments
[0052] Although the embodiments described above relate particularly to scanning mirrors, the principles of the present invention may similarly be applied in other types of devices, particularly (although not exclusively) MEMS devices. Some examples are shown in the figures that follow.
[0053] FIG. 7 is a schematic side view of an inertial sensor 50 , in accordance with an embodiment of the present invention. Sensor 50 may serve, inter alia, as an accelerometer or crash sensor. The frame in this case is a proof mass 52 , which is mounted on a torsion spring 54 , causing the mass to rotate by a calibrated amount in response to acceleration. Rotation of mass 52 can be detected, for instance, by a capacitive sensor 58 or by optical sensing, using a LED emitter 60 and one or more photodiodes 62 . (Both types of sensors are shown in the figure for the sake of completeness.) Alternatively, other sorts of sensors may be used for this purpose, such as or electromagnetic or piezoelectric sensors.
[0054] To enable inertial sensor 50 to operate with high sensitivity about the rotational axis of torsion spring 54 , without breakdown due to shocks in other directions, the torsion spring is made long and thin for torsional flexibility, and the gap between the torsion spring and proof mass 52 is filled with a soft filler material 56 . As in the embodiments described above, any suitable material with high Poisson ratio and low Young's modulus may be used, such as adhesives and other polymers, as well as foams and other porous materials.
[0055] FIG. 8 is a schematic side view of an energy-harvesting device 70 , in accordance with another embodiment of the present invention. In this embodiment, the frame is a motion arm 64 , which is mounted to rotate about a torsion spring 66 . Motion of arm 64 actuates an energy-harvesting assembly, by translating a permanent magnet 72 along the axis of a coil 74 . The translation generates current in the coil, which can be used to charge a battery 76 or drive a low-power electrical device. Motion arm 64 rotates in response to external inertial forces, such as motion of an arm or leg of a user on which energy harvesting device 70 is mounted. In order to maximize the range of motion of motion arm 64 relative to the applied inertial force, torsion spring 66 is made long and thin. The gap between the torsion spring and the motion arm is filled with a suitable soft material 68 , as in the preceding embodiments, in order to enhance the robustness of the device against shocks and other transverse forces.
[0056] FIG. 9A is a schematic illustration of a gyroscopic sensor 80 , in accordance with yet another embodiment of the present invention. Two masses 82 are suspended on a base 84 by suspension beams 86 , and are harmonically actuated in the in-plane direction (in the X-Y plane) by a suitable drive, such as a parallel plate, comb drive, piezoelectric drive or electromagnetic drive. In the pictured embodiment, electrodes 88 are driven with currents at the appropriate frequency to actuate masses 82 . When sensor 80 is rotated about the Y-axis, base 84 will harmonically tilt about torsion hinges 90 , with a tilt amplitude (Ωy) proportional to the rate of rotation. The tilt may be measured using capacitive, optic, electromagnetic, or any other suitable means of detection, as described above with reference to FIG. 7 .
[0057] FIG. 9B is a schematic detail view of hinge 90 and a surrounding frame 92 in sensor 80 , in accordance with an embodiment of the present invention. The gaps between hinges 90 and frame 92 are filled with a suitable filler material 94 to damp transverse forces, as explained above.
[0058] FIG. 10 is a schematic detail view of an elastic hinge assembly 100 , in accordance with an alternative embodiment of the present invention. In this embodiment, an array of carbon nano-tubes 102 are formed across the gaps between hinge 26 and frame 28 . Nano-tubes 102 are not “soft” in the sense defined above, since such nano-tubes typically have a higher Young's modulus than do the silicon hinge and frame. Nano-tubes 102 in hinge assembly 100 , however, are configured in such a way as to give the desired effects of rotational compliance and transverse stiffness. Nano-tubes are inherently very stable and thus may have some advantages over polymeric materials for the present purposes.
[0059] FIGS. 11A and 11B schematically illustrate a hinge assembly 110 of alternative design, in which elastic hinge 26 comprises a broad anchor 112 connecting the hinge to base 22 , in accordance with an embodiment of the present invention. The broadening in-plane transverse dimension of anchor 112 , together with filler material 30 in the gaps, is useful particularly in decreasing the shear stress that may arise in hinge 26 due to in-plane or out-of-plane shocks. This feature of anchor 112 is illustrated particularly in FIG. 11B , which shows the effect of both torsional deformation and deflection in hinge assembly 110 .
[0060] FIG. 12 is a schematic top view of a resonant radial spring assembly 120 , in accordance with an embodiment of the present invention. Assembly 120 , which is produced by a MEMS process, is based on an element having the form of a spiral bending spring 122 and has weak stiffness in the in-plane direction. A polymer 124 is applied to the gaps in the spring, in the manner described above, to prevent the in-plane movement without substantially increasing the rotational stiffness. In other words, polymer 124 allows spring 122 to bend, but increases the stiffness of assembly 120 against sideways compression. This embodiment illustrates that the principles of the present invention are applicable to various types of springs, and not only the sort of hinges that are shown in the preceding figures.
[0061] Although the implementation examples described above relate to MEMS devices, the principles of the present invention may similarly be applied in hinges produced by other technologies and on other scales, not only in micro-scale systems, but also in meso- and macro-scale devices. It will thus be appreciated that the embodiments described above are cited by way of example, and that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof which would occur to persons skilled in the art upon reading the foregoing description and which are not disclosed in the prior art. | A mechanical device includes a long, narrow element made of a rigid, elastic material. A rigid frame is configured to anchor at least one end of the element, which is attached to the frame, and to define a gap running longitudinally along the element between the beam and the frame, so that the element is free to move within the gap. A solid filler material, different from the rigid, elastic material, fills at least a part of the gap between the element and the frame so as to permit a first mode of movement of the element within the gap while inhibiting a different, second mode of movement. | 1 |
BACKGROUND OF THE INVENTION
The invention relates to a mounting clip for supporting pipes generally vertically, obliquely or upright, in particular pipe systems of power stations, comprising a support frame adapted to encompass the pipe or the like and having ends which are provided with transverse support plates which are in turn connected to a suspension system.
Pipe clips which serve as a connection between the pipe line and the shock absorbing elements of a pipe line system in power station engineering applications are specifically designed for accepting dynamic forces. To this effect, such conventional pipe clips are made in the form of a rigid support trestle serving, on the one hand, to establish a connection to the pipe, and, on the other hand, to a stationary support. The rigid support trestle is either a welded construction or a steel casting of a relatively heavy weight whose manufacture is involved and expensive. Since a great number of such pipe clips are required for a pipe line system, the financial expenditure for such conventional pipe clips is high, apart from the fact that it is difficult to handle the heavy and rigid pipe clip.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a pipe mounting clip of the foregoing type whose weight is considerably reduced and can be easily handled. Further, the clip of the invention can be adapted easily to various pipe sizes. According to the invention, the problem of varying pipe sizes is solved in that the pipe clip is composed of individual transverse and longitudinal plate members, viz. two longitudinal plates, two transverse plates, and two carrier plates, elements or members, and the latter are all retained in a box-shaped configuration by mechanical interlocking means through the use of intermeshing slot-like connections.
The box-shaped pipe mounting clip can be produced simply and its handling is simple as well. Further, the pipe clip can be easily mounted and, within a predetermined range, it may be adapted to accommodate and support various sizes of pipe. Moreover, due to the invention the weight of the pipe clip may be 6 to 7 times less than that of a conventional pipe clip design.
According to another feature of the invention, the longitudinal plates have vertical slots at their ends while the central region of each longitudinal plate upper edge includes a cutout or slot situated symmetrically relative to the center and receives therein carrier elements. Transverse end plates are provided with vertical slots which lock with the slots of the longitudinal plates. By interfitting the longitudinal plate slots and the transverse plate slots, a simple box shape of the support frame, together with a reliable locking of the nested plates, is realized. A central area of the transverse plates comprise the suspension means for taking the load by the support frame. The suspension means at the transverse plates suitably consists of a closed hole through which a suspension eye or the like may be inserted.
The carrier elements receive and support the weight of an associated pipe by means of lugs secured at centers of the longitudinal plates. Preferably, one side of the carrier elements include corner cutouts, while the other side includes a semicircular cutout adapted to embrace the exterior of an associated pipe. The longitudinal sides of the carrier elements are provided with short transverse slots or longitudinal holes which are used to receive bolts carried by the longitudinal plates. Thus, the pipe is safely supported at the center of the pipe clip.
According to another feature of the invention, one edge of the semicircular cutout of each carrier element may comprise sections projecting beyond the center of the latter and, at the other end of the semicircular cutout, there are sections set back from the center so that the partition joints or faces between the two carrier elements placed against each other are disposed offset from the cutout center. Due to the latter construction the receiving tappets which are mounted diagonally, if possible, with respect to the longitudinal axis of the pipe cross section will not be positioned on a partition joint between the carrier elements.
A clamping plate is secured at the underside of the ends of the longitudinal plates to underengage the adjacent transverse plates to insure that without a load, the box-shape of the pipe clip will be maintained and the plates will not become disassembled.
In another embodiment of the pipe clip of the invention, the longitudinal plates may be provided with a central opening or slot which receives pins secured to the pipe. Further the longitudinal plates may be additionally secured in spaced relationship to each other by transverse bolts.
With the above, and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1, 2 and 3 are respective elevational, plan and side views of one embodiment of a pipe clip of the invention, and illustrates two pairs of longitudinal, transverse and pipe carrier plates assembled in a generally box-shaped configuration.
FIG. 4 is a side elevational view of one of two longitudinal plates and illustrates a central upwardly opening slot and two downwardly opening slots.
FIG. 5 is a side elevational view of one of two transverse plates of the pipe clip, and illustrates a pair of upwardly opening slots thereof.
FIG. 6 is a top plan view of the two pipe carrier elements of the invention, and illustrates semicircular slots collectively defining a pipe-receiving opening.
FIGS. 7 and 8 are plan and elevational views, respectively, the latter partly sectioned, of a safety clamping plate, and illustrate an opening for receiving a clamping bolt.
FIG. 9 is a perspective view of the pipe clip, and illustrates the fully assembled configuration thereof.
FIG. 10 is a perspective view of another embodiment of the box-shaped pipe clip of the invention, and illustrates an opening in a longitudinal plate receiving therein a projection of a pipe.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A novel pipe clip 1 of the invention (FIGS. 1-3) is composed only of individual plates or plate members comprising a pair of longitudinal plates 2, 3, transverse plates 4, 5 and carrier plates or elements 6, 7 interlocked together to form a box-shaped configuration for receiving therebetween a pipe 8. The locking of the individual plates 2 through 7 is effected by means of intermeshing and interlocking slot connections, as will be made more apparent hereinafter.
The longitudinal plates 2, 3 are provided near their ends (unnumbered) with slots 10, 11, which are adapted to be interlocked with slots 18, 19 of the transverse plates 4, 5 In the central region (unnumbered) at the top edges of the longitudinal plates 2, 3 there are cutouts 12 for receiving the carrier elements 6, 7. Further, each longitudinal plate 2, 3 carries threaded bolts 13, 14 at the lower edge and threaded bolts 15, 16 in each cutout 12. The purpose of the bolts 13 through 16 will be explained hereafter.
The transverse plates 4, 5 are interlocked with the longitudinal plates 2, 3 so as to serve as spacers for the latter, as is best shown in FIGS. 2 and 9. Vertical slots 18, 19 are provided near the ends of the transverse elements 4, 5 and open upwardly through upper edges (unnumbered) of the latter. The vertical slots 18, 19 interlock with the slots 10, 11 of the longitudinal plates 2, 3 in the manner clearly evident from FIGS. 4, 5 and 9. in the central area of the transverse plates 4, 5 suspension means is provided, preferably in the form of hole 21 for connection to a support element.
The carrier elements 6 and 7 are also formed from plates or plate members by punching or flame cutting a larger plate. The free ends (unnumbered) of the carrier elements 6 and 7 comprise slots or cutouts 23, 24 by which the carrier elements 6, 7 may be seated in the recesses or slots 12 of the longitudinal plates 2,
At their opposing transverse sides or edges the carrier elements 6, 7 are provided with semicircular slots or cutouts 25, 26 adapted to receive therebetween the outside diameter of the pipe which is to be supported. The longitudinal sides or edges of the carrier elements 5, 6 include short longitudinal slots 28, 29 to enable threaded bolts 15, 16 carried by the longitudinal plates 2, 3 to extend therethrouqh.
At on end of each semicircular cutout 25, 26 each carrier element 6, 7 includes a portion or section 30, 31 (FIG. 2) projecting beyond a plane through the center of its associated cutout and a section or portion 32, 33 which does not project through the center plane. The carrier elements 6, 7 are so disposed with respect to each other that a long section or portion 30, 31 is always opposed to a short portion or section 32, 33, respectively. The carrier elements 6, 7 abut against the bottom of lugs or tappets 35 which are welded to the pipe 8 through which the pipe 8 is generally vertically supported by the pipe clip 1. Due to the mutually offset sections 30, 32 and 31, 33 and the points at which the tappets 35 are disposed on the pipe 8, the tappets 35 are prevented from being situated in the gaps between the sections 30, 32, 31, 33.
As is evident from FIG. 9, the longitudinal plates 2, 3 and the transverse plates 4, 5 form a closed box shape by interlocking or intermeshing with each other through the slots 10, 11 and 18, 19. Since the transverse plates 4, 5 are held in load-bearing relationship to a stationary support, the longitudinal plates 2, 3 inserted into the transverse plates 4, 5 are supported by the latter. To prevent the transverse plates 4, 5 from being displaced and detached from the longitudinal plates 2, 3 under no load conditions and/or when the clip 1 is not in use, a safety clamping plate 36, 37 is provided at the end of each longitudinal plate 2, 3 and threaded bolts 13, 14 at the ends of the longitudinal plates 2, 3 may pass. The clamping plates 36, 37 are secured by nuts (unnumbered) screwed on the bolts 13, 14 (FIGS. 4 and 9).
Due to the corner cutouts 23, 24, the carrier elements 6, 7 seat in and engage the recesses or slots 12 of the longitudinal plates 2, 3 while the longitudinal plates 2, 3 are also held thereby in transverse spaced generally parallel relationship. When the carrier elements 6, 7 are placed in the slots 12, they are secured by threaded bolts 15, 16 extending through the slots 28, 29. The carrier elements 6, 7 are prevented from lifting by nuts 38 threaded tightly against the carrier elements 6, 7.
The embodiment of a pipe clip 40 of FIG. 10 is identical to that of FIGS. 1 through 9 except for the construction of longitudinal plates 2a, 3a. The mounting of the pipe 8a to the pipe clip 40 is achieved by projections, lugs or pins 41, fitted., e.g., by welding, at diametrically opposite points of the periphery of the pipe 8a. The projections 41 engage in bores, openings or slots 42 in the longitudinal plates 2a, 3a. In this pipe mounting clip 40, the carrier elements 6 and 7 are substituted for by the projections or carrier elements 41. To additionally maintain the spacing between the longitudinal plates 2a, 3a, transverse spacers 43, 44 are provided in the form of bars with threaded ends which, on both sides of the longitudinal plates 2a, 3a, may be provided with nuts 45 and 46 between which the longitudinal plates 2a, 3a are clamped.
Although a preferred embodiment of the invention has been specifically illustrated and described herein, it is to be understood that minor variations may be made in the apparatus without departing from the spirit and scope of the invention as defined in the appended claims. | A clip for supporting pipes or the like in a generally upright orientation comprising a pair of generally transversely spaced longitudinal plates each having opposite ends, a pair of generally longitudinally spaced transverse plates each spanning the longitudinal plates at the opposite ends thereof, and intermeshed slots at the ends of the longitudinal and transverse plates retaining the same in assembled relationship. A pair of carrier elements having opposing arcuate slots transversely span the longitudinal plates and are interlocked with a pipe for suspending the latter from a suitable support. | 5 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to wheeled vehicle support devices and more particularly to a novel apparatus by which a single wheel ground contact area can be increased employing a flotation augmentation means.
2. Brief Description of the Prior Art
Numerous attempts have been made to improve the soft-soil and snow performance of wheeled vehicles. In the case of conventional wheeled vehicle designs, for example, automobiles, trucks, and farm tractors, emphasis has been placed on the grouser effect of chains and the like to improve thrust by a soil shearing action. While this approach has enjoyed a measure of success with powered driving wheels, unpowered wheels on trailers, aircraft, farm implements, and construction equipment have represented a compromise in terms of tire and wheel design. On the one hand, the desirable goal of a relatively high-pressure tire for operation on improved surfaces such as paved roads and airfields conflicts with tire characteristics desired, on the other hand, in soft soils and snow. In the latter conditions, increased ground contact area and greater flotation are essential. It is a well known principle in soil mechanics that increasing the lengthwise dimension of the ground contact area is significantly more effective mobility-wise than increasing the width of said contact area.
The compromises afforded the designer up until now have, however, been limited, and in applications demanding a minimum volume running gear, such as an aircraft landing gear, the high-pressure tire, minimum envelope approach has prevailed. This situation of course, has restricted high-performance aircraft, for example, to ground operations on improved surfaces. Likewise, the characteristic stress concentrations on these improved surfaces dictates the depth and composition of the subgrade as well as the thickness of the pavement and base.
If considered in a strict military context, the limited ground mobility, or limited ability to traverse anything short of an improved paved surface represents a serious limitation for today's military aircraft. Additionally, the vulnerability of the high pressure, heavily loaded tire to damage or failure from rocks and debris argues in favor of some form of protective barrier.
Therefore, a longstanding need has existed especially related to aircraft, to provide a flotation device for single and dual wheels to increase ground contact area, ideally, in a lengthwise manner, and also to serve as a protective barrier from rocks, debris, and the like.
SUMMARY OF THE INVENTION
Accordingly, the above problems and shortcomings are obviated by the present invention which provides for a substantial increase in ground contact area by means of a novel apparatus having a unique track geometry. The additional benefit of tire protection is gained by the enveloping characteristics of the tracks with respect to the tire tread and side walls.
In one form, the invention includes at least three elongated track segments having adjacent ends releasably joined together in end-to-end relationship so as to define a circular track substantially encasing the tread and sidewalls of a tire movably carried on a wheeled vehicle. Each track segment includes a plurality of identical block members wherein each of such members is provided with a base and integrally formed side guide horns extending in fixed spaced apart relationship. Hinge means movably join respective block members together and the configuration of each of said track members and side guide horns is such that means are defined for increasing ground contact area, particularly the length of said area, as compared with the ground contact area of the wheeled tire per se.
Therefore, it is among the primary objects of this invention to provide a novel auxiliary flotation track for single or dual wheels to facilitate operation over unimproved terrain, soft-soil and snow.
Another object of the present invention is to provide a protective barrier between a relatively high-pressure pneumatic tire and sharp rocks and other debris likely to be encountered when operating over unimproved surfaces.
Another object of the present invention is to provide for rapid installation and removal of an auxiliary flotation track under field conditions.
Still a further object of this invention resides in the novel method for extending track contact length by utilizing guide tip means to project a load bearing track block beyond full tire contact.
Yet another object of the present invention is to provide a novel track apparatus for the tires of a wheeled vehicle adapted to accommodate lateral forces induced by turning, obstacle negotiation, and side-slope operation as well as increasing ground contact area.
BRIEF DESCRIPTION OF THE DRAWINGS
The features of the present invention which are believed novel are set forth in the appended claims. The present invention, both as to its organization and manner of operation, 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 side-elevational view illustrating the novel tire support or flotation track apparatus of the present invention for increasing the effective ground contact length;
FIG. 2 is an enlarged transverse cross sectional view of the apparatus shown in FIG. 1 as taken in the direction of arrows 2--2 thereof; and
FIG. 3 is a fragmentary plan view of the present invention illustrating the internal convex cone-shaped termination of a typical guide horn as taken in the direction of arrows 3--3 of FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, the novel flotation track apparatus of the present invention is illustrated in the general direction of arrow 10 and is shown in connection with a conventional, high-pressure, tire and wheel combination. The tire is identified by numeral 11 and is illustrated as being mounted on a wheel such as is employed in aircraft or the like and identified by numeral 12. Typical vehicles employing this type of tire and wheel combination that benefit from the added utility of the auxiliary flotation track 10 include trailers, semi-trailers and farm implements. Such crops as lettuce, celery and rice require implements and harvesting equipment with high-flotation running gear. Also, the additional utility of employing a trailer, for example, designed for operation over improved highways in a field or paddy for crop gathering would result in a considerable savings when the subject invention is employed. Likewise, oil and mineral exploration operations benefit from the present invention in that road-mobile equipment could be employed in remote areas requiring high-flotation running gear and tire protection.
Potential military applications are numerous and include all types of aircraft with wheeled landing gear as well as combat and tactical ground vehicles. With the flotation track apparatus installed after landing, an airplane or helicopter may be towed or taxied over unimproved terrain for concealment or dispersal. Conversely, the aircraft may be moved over random routes for access to runways, highways or other suitable surfaces for take-off. Additional possibilities include the recovery of disabled aircraft requiring significant reductions in landing gear unit ground pressures.
Referring now in detail to FIG. 1, the flotation track apparatus 10 includes at least three segments which are joined together by a releasable means so that a continuous circular tread is produced over the tire 11. A single segment is illustrated extended between releasable connector pins 13 and 14. A second segment is illustrated between releasable pin 14 and a releasable pin 15. A third segment is established between releasable pin 15 and releasable pin 13. Therefore, it can be seen that a continuous tread is provided which encompasses the tread and sidewall of the tire 11.
Each of the track segments includes a plurality of track block members such as block member 16 associated with releasable connector pin 13 and a track block member 17 associated with the releasable connector pin 15. The plurality of track block members are joined together at their adjacent ends by a hinge means taking the form of a connector pin which is inserted through a bore in the interwoven tangs of the hinge means. A typical connector pin for interconnecting adjacent ends of track block members is identified by numeral 18 and is joining track block member 17 with track block member 20. The track block member 16 is joined to an adjacent track block member 21 by means of a releasable connecting pin 13 which is held in place by a locking pin 22. When it is desired to install the segments onto a tire, or to remove the segments from a tire, the lock pin 22 is pulled so that the connector pin 13 can be withdrawn to disconnect the segments. At this time, the remaining segments can be disengaged from the tire and laid flat on the ground so that the wheel is not encumbered.
Referring now in detail to FIG. 2, it can be seen that the track block member 20 includes a pair of spaced apart tangs 25 and 26. It can also be seen that the track block member 17 includes similar tangs 27 and 28 which are offset from the tangs 25 and 26 so as to be aligned permitting co-axial and co-extensive relationship of a common bore extending between all of the tangs. The bore associated with each of the tangs is provided with a bushing or sleeve and such a bushing is illustrated by numeral 30 with respect to the tang 28 carried on track block member 17. The connector pin 18 is inserted through the bore in close relationship with the bushing or sleeve 30 and a selected end of the bore is reduced as illustrated by numeral 31 so as to serve as a stop once the pin has been properly inserted. Preferably, the corresponding end of the connector pin associated with the stop 31 is tapered to correspond with the reduced diameter of the bore. This end is identified by numeral 32. The length of the pin 18 is somewhat shorter than the length of the combined bore into which it is inserted so that a retention pin, such as a roll pin identified by numeral 33 may be inserted through a hole in the block 20 and pass through the bore identified by numeral 34 to prevent the connecting pin 18 from dislodging.
Continuing with the detailed description of FIG. 2, it can be seen that the track segment connector pin 13 is inserted into the bore of combined tangs 40 and 41 associated with track block member 16 and tangs 42 and 43 associated with track block member 21. In a similar fashion, the bores are provided with suitable sleeves or bushings such as the bushing 44 associated with tang 43. Also, the end of the segment connector pin 13 is tapered to conform with the reduced bore of the tang 41 so that the pin will bottom-out when properly inserted. The pin 13 includes an outwardly projecting portion 45 having suitable flats provided thereon so that tools such as wrenches or the like may be placed thereon in the event sticking occurs during removal of the connector pin. The connector pin is detachably connected to the assembly by means of locking pin 22 and pull ring arrangement which passes through aligned holes in the tang 42 and the end of the connector pin 13.
It can also be seen that each of the respective track block members is of a U-shaped configuration in end view and that each of the members includes a base 46 and spaced apart side guide horns 47 and 48. Each of the horns includes an exterior surface 50 which slopes from the base 46 inward towards the center of the device. Also, each of the guide horns terminates in a rounded tip 51. By means of the rounded tip 51 and the sloping exterior sides, a configuration is produced and defined which permits the track block members to be rotated with respect to each other as shown in FIG. 1. In FIG. 1, it can be seen that the free rounded ends of the side guide horns are of a lesser dimension than the end of the guide horns which are integrally formed with the respective bases 46. The object of this configuration which may be best determined by reference to FIG. 1, is to cause track block members (X 1 and X 2 ) not fully under and in full intimate contact with the tread of the tire to be projected out horizontally to increase track contact area, particularly in a lengthwise manner. The horizontal projection of said track block members occurs because of the interaction of track block members 21, 16, and X 2 , and the configuration of their side guide horns and the dimensional relationships between the rounded tips of said horns and the centerline of the connector pins (such as 13) joining the track blocks. In further explanation, with the track trained loosely around the tire, as in FIG. 1, track block member 21 pivots on connector pin 13 and the rounded tips of its guide horns impinge on the guide horns of track block member 16. This levering action causes track block member 16 to assume the position shown in FIG. 1, and it, in turn, through the connector pin linking it to track block member X 2 and impingement of the tips of its guide horns on the tips of those X 2 , levers said track block member X 2 into the horizontal position shown.
Tracking, or the ability of the flotation track apparatus to provide a smooth path for the wheel tire combination is enhanced by the convexity of the cone-shaped configuration identified by numeral 52 of the guide horn internal contact surface. This surface geometry transitions to the horizontal internal face of the track block and terminates at the center line vertex.
This latter construction is more clearly shown in FIG. 3 wherein it can be seen that each half of the block member includes such a cone-shaped configuration as identified by numeral 52 and 53 associated with track block member 16. The spaced guide horns of member 16 are identified by numerals 54 and 55 and the apex of the cone-shaped configurations are opposing each other at the point identified by numeral 56.
In actual practice, to facilitate quick installation and removal in the field, a typical track assembly is formed from the three identical segments consisting of the plurality of single-pin track block members. The segments are joined with removable pins 13, 14, and 15, at least one of which will be in a convenient position for installation or removal despite the random rotation of the wheel track combination.
The configuration and design of the integral track block guide horns contribute to the unique performance characteristics of the present inventive concept. In addition to the conventional function of accommodating lateral forces induced by turning, obstacle negotiation, and side-slope operations, the guide tips provide the means by which the increased ground contact length or aspect ratio is achieved in soft-soil or snow conditions. Alternatively, a single, centered guide horn positioned to occupy the cavity between a dual wheel arrangement as found on highway trucks, trailers and the like can be configured with the same radiused guide tips and function in the same manner to project a load bearing track block beyond full tire contact.
This feature of the present invention, when combined with the flat lateral design of the track, provides the increased contact area desired. When contrasted to the short elliptical planform of a conventional tire contacting a surface, the lengthwise oriented, rectangular footprint realized with this invention results in a more effective, sinkage resistant pressure distribution. This attribute improves the potential for avoiding local soil failures, and hence, immobilization.
Should it be desired to employ the flotation track in a single or tandem powered wheel application, the convex design of the track block/tire interface contributes to the transmission of driving torque. Likewise, for both unpowered and powered wheel applications, the track block/tire interface geometry contributes to the transmission of braking forces.
While the potential advantages of the present invention have been briefly described, it will be obvious to those skilled in the art that changes or modification thereof to accommodate the dimensional restrictions of wheel housings, chassis frames, and landing gear geometry may be made without departing from this invention in its broader aspects and, therefore, the object of the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention. | A wheeled vehicle flotation augmentation device is disclosed herein having at least elongated segments releasably connected together in a continuous and endless series of track block guides so as to form a circular tread about the periphery of a single wheel of the vehicle. The plurality of track block guides in the series are hingably coupled together and the adjacent ends of each segment of track block guides are joined by releasable pins. Each track block guide includes a flat base having outwardly projecting and spaced apart side horns which are separated by the wheel of the vehicle. The terminating tips of the side horns are rounded to aid in projecting a load bearing track block beyond full tire contact and so provide increased ground contact length or aspect ratio in soft-soil or snow environments. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part application of pending U.S. Ser. No. 11/405,742 filed Apr. 18, 2006, which is a continuation-in-part application of U.S. Ser. No. 10/474,892, filed Oct. 10, 2003, which is a national stage filing under 35 U.S.C. 371 of International Application No. PCT/GB01/05136, filed Nov. 21, 2001.
TECHNICAL FIELD
[0002] This invention relates to a device for monitoring the activity of a person working in an office environment and notifying that person of a specified pattern and frequency of their activity or inactivity, in order to reduce the risk of them developing deep vein thrombosis.
[0003] The present invention finds a particular use in the prevention of deep vein thrombosis (DVT), which is often caused by extended periods of inactivity, and it will be primarily described with reference thereto.
BACKGROUND OF THE INVENTION
[0004] Deep vein thrombosis is a condition resulting from the lack of blood flow in the veins and the condition is related primarily, but not exclusively, to the legs. Blood flow tends to slow down or stop when there is prolonged inactivity, especially when seated, as would happen in an office or when working on computer or at a telephone especially in a cramped space. More specifically deep vein thrombosis occurs when a clot forms in the deep veins within the calf or thigh muscles. It is usually a spontaneous condition that occurs in people especially at risk, such as those with heart disease, those who smoke or consume alcohol and those that are generally overweight.
[0005] Any period of prolonged inactivity can generally trigger the condition and medical research suggests that those over forty years of age are at ever increasing risk. Warning signs are pain and tenderness in the leg muscles, redness and swelling of the skin. If the blood clot moves to the lung (a pulmonary embolus), then breathing difficulties can occur. A clot travelling on to the heart can cause death or if it travels to the brain a stroke is a possibility. There are well-documented cases of people suffering from this condition during long haul plane journeys and there have been some deaths attributed to DVT. There is also a risk in work environments where employers need to ensure the standards of health and safety for their workers.
[0006] It is to be expected that in office conditions people will stay still in their chairs for extended periods of this time. This cannot be prevented on an individual basis and this is where a problem may arise. Furthermore, at such times, people may for one reason or another remain essentially motionless. This inactivity reduces the blood flow in the legs and the potential problem of DVT becomes a factor.
[0007] Regular use of the legs dramatically reduces the risk of DVT. However, the employer has no way of ensuring that suitable exercise is done by their employees, despite the fact that the health and safety of those workers is at least partially the employer's responsibility.
[0008] Previous attempts have been made to monitor the movement of patients such as those described in U.S. Pat. No. 5,941,836, U.S. Pat. No. 6,646,556, U.S. Pat. No. 4,536,755, U.S. Pat. No. 5,523,742, U.S. Pat. No. 4,064,368 and U.S. Pat. No. 6,445,298. None of these are designed for or suitable for use by workers in an office environment because they are large, cumbersome, suitable only for lying down and/or unable to distinguish relevant exercise movement from background movement caused by incorrect activity or the motion for example of a wheeled chair upon which the person is sitting.
BRIEF SUMMARY OF THE INVENTION
[0009] The present invention aims to provide a mechanism by which the motion or lack of motion of a person may be monitored and remedial action taken if the exercise is deemed inappropriate. In the context of DVT prevention it aims to reduce the risk of DVT occurring and move responsibility from the employer to the individual worker by providing them with a device that will warn of lack of sufficient and suitable movement/exercise of the limbs.
[0010] The invention aims to provide a device that detects a deficiency in a worker's exercise regime; alerts the worker to the increased risk of DVT and promotes the appropriate exercise regime. To find utility in a office setting the present invention provides a device that is small and portable enough to be used in an office setting without compromising the comfort and safety of the worker; that can detect a specific exercise in a vibration rich environment; can learn the appropriate exercise habits of an individual, calculate, and automatically adapt to reduce an individual worker's risk; and is able to adjust its ability to detect exercise as the environment changes.
[0011] According to the present invention there is provided a office worker activity monitoring device for monitoring the activity of a user in an office environment, the device comprising a carrier adapted for releasable attachment to a user, a motion sensor mounted on the carrier to detect motion of the user; a processor also mounted on the carrier that receives motion information from the motion sensor and which differentiates motion attributable to the user performing a defined exercise from the overall pattern of motion detected, and an alarm adapted to be triggered should a time period elapse without the motion attributable to the user performing the defined exercise being detected, wherein the defined exercise and time period are such that the alarm is triggered if the user does not correctly exercised sufficiently frequently to reduce the risk of deep vein thrombosis, and wherein all of the components of the device are self contained on the user such that the device is portable within the office environment.
[0012] The processor may include a timer adapted to count the time period, and be reset if the user correctly performs the defined exercise. The timer may be a separate component linked to the processor.
[0013] The type of motion sensor used is important, and it is highly preferred that the motion sensor comprises a movable contact head mounted on a shaft, and contact plates at right angles to each other and adjacent the contact head to detect movement radially with respect to the shaft by contact of the head with the contact plates. The motion sensor may also include a calibration actuator that is in contact with the shaft and is able to detect vibrations and provide this data to the processor and which may also under control of the processor adjust the motion of the contact head. This can be used to minimise the effect of background vibrations. The calibration actuator may be linked to the processor to dynamically adjust the motion of the contact head to minimise the effect of background motion.
[0014] A small, discrete, self contained device is essential as it must be worn by a user without causing discomfort or danger. Therefore it is preferred that the carrier includes a shell within which the processor, motion sensor and alarm are mounted. This shell should also house all other components such as a power source.
[0015] The processor may preferably include a computer memory and software adapted to perform an analysis of data received from the motion sensor to differentiate the motion attributable to the user performing the defined exercise from the background motion. The software may be stored in the memory and run in the processor in several modes of operation. This may include: a learning mode in which specific performance of the defined exercise is detected and used to calibrate the device to minimise background motion; and a normal mode during which the calibrated device monitors the activity of the user as they work.
[0016] The device may be further provided with a user interface to provide information to the user and/or to allow input by the user of information in to the device. Such user inputted information may include information selected from the group consisting of the user's height, the user's weight, the user's age and the user's lifestyle.
[0017] The device may be used to compliment other types of DVT prevention equipment. It is known to use an air bag exercise apparatus which can be used by a seated person to reduce risk of developing DVT. This apparatus relies on the user to undertake the exercise and so does not ensure that they are reminded to do so. The present invention also provides an exercise apparatus provided with an activity monitoring device as previously described which is adapted to monitor the correct use of the exercise apparatus and sound the alarm if insufficient or incorrect use is made of the apparatus. The apparatus could be a two chamber inflatable device, and this could also be provided with a pump for inflation thereof.
[0018] The device can monitor the activity of the entire body or of a specific limb and in order to monitor such activity it is essential that the sensor be positioned so that it may detect the movements of one or more part of the body. It is preferred that the sensor is held against the user and more particularly the limb of a user, and so the carrier may include an attachment means to permit removable attachment of the device to a user. Those attachment means may take any suitable form, but for attachment to a limb, they may comprise a strap that is adapted to pass around that limb. Such a strap may be made such that it may be stretched to pass over the hand or foot and then grip the limb once fastened. Alternatively the strap may be in two parts, the free end of each part being provided with means for inter-attachment, such as a two part hook and loop fastener (for example those sold under the trade name Velcro®), or a buckle. Releasable adhesive could also be used to fix the device to a limb or clothing. Ideally the device should be as small and easy to attach to the user as possible, it is therefore preferred that the carrier includes a mechanism for the releasable attachment to the user or the user's clothes. A catch or pin to engage the user's belt or clothes is highly suitable. The device is preferably adapted for a single point of attachment, ie it does not have attachments to two separate and relatively-movable parts.
[0019] The motion sensor must be adapted to discern various patterns of movement characteristic of the defined exercise routine, from other motion. This allows the device to discern between different types of activity and only to record the performance of correct activity. This prevents the suppression of the alarm by insufficient or inappropriate movement.
[0020] Vibration can be classified into one or more of the following categories: periodic, random, resonant and harmonic. A periodic vibration repeats itself once every time period. In real terms dorsi and plantar flexion (which are suitable exercise motions) cause such once per cycle vibration which is periodic by nature. Random vibrations do not repeat themselves, and are not related to a fundamental frequency. An example in an office might be the rolling of a chair over the floor.
[0021] Resonant vibrations occur at the natural frequency at which an structure or mechanical system is inclined to vibrate. All things have one or more resonant frequency. Resonant vibrations are the result of a response in a mechanical system to a periodic driving force. Harmonic vibrations are exact multiples of a fundamental frequency.
[0022] The type of exercise motion that the motion sensor is adapted to monitor may be preset during manufacture, as may the time period for its completion. Such manufacture settings could adapt the device to a particular type of use or user (e.g. overweight as compared to ideal weight). Alternatively, the type of predetermined motion and indeed the preset time period may be adjusted to allow the device to be swapped between different uses. This adjustment may be conducted by reprogramming the devices between different modes, using controls on the device or by control remotely from the device. The device may also be adapted to permit user interface, so that characteristics of the user, the office environment and the user's lifestyle can be input directly into the device to determine the required form, duration and frequency of exercise.
[0023] The alarm must be able to notify the user, and possibly persons other than the user, of the correct or incorrect activity, and may therefore, dependant on the end use, take several different forms. The alarm may include at least one of an audible signal generator such as a speaker, a light source such as a flashing LED, a vibrator such as is used in mobile phones and a transmitter connected to a remote notification system. Such a transmitter might be used when it is additionally, or alternatively, desired to notify a person other than the user (wearer) of the device.
[0024] Means for transmitting and/or receiving data may be included, either as part of the alarm, or in addition to the alarm, and these can allow remote control and monitoring of the device.
[0025] The device may be adapted for attachment to a person who desires to correctly carry out a specific exercise. In such an embodiment, the type of predetermined motion may be set to the pattern generated by the correct completion of the specific exercise routine, and the preset time period of the timer is set so that the alarm is triggered if the exercise is not correctly performed at the required frequency by the person wearing the device.
[0026] In a more sophisticated version of the invention the following sequence happens. A wearer will be given an alert on activation of the device. The alert might comprise the flashing of the LED, a buzz from a vibration motor or a message on a screen. The microprocessor could allow for the LED to flash in time with an exact exercise being achieved, in so doing it could train the wearer to do a specific regime of exercise. The LED will flash every fifteen seconds to show its wearer that it is functioning correctly.
[0027] In a further use of the LED, it could be that should the wearer refuse or fail to do the exercise in any one or more period of monitoring, then the flash rate of the LED could be changed by the processor to two flashes every fifteen seconds to indicate this. This has the function of alerting others that the wearer refused or failed to do the determined exercise regime recommended.
[0028] The device would include a timer that can monitor activity over a suitable period such as fifty to sixty minutes and if insufficient/inappropriate exercise is detected in that period then it will cause a warning, such as three distinct buzzes of the vibration motor to warn a user to do the exercise regime.
[0029] On completion of the exercise another signal can be sent to the wearer, e.g. via the vibration motor, to indicate to the wearer that they can stop doing exercise. The device could then reset its clock and continue to monitor for a further fifty or sixty minutes.
[0030] According to the present invention there is also provided a method of preventing deep vein thrombosis in a worker working in an office environment, the method comprising:
providing the worker with a self contained activity monitoring device comprising a motion sensor to detect motion of the worker; a processor that receives motion information from the motion sensor, and an alarm, the activity monitoring device being mounted on the worker whilst working; defining, on the basis of characteristics of the worker, an exercise pattern to be performed, including a frequency time period for its repetition, to reduce the risk of deep vein thrombosis; processing in the processor the motion detected by the motion sensor during the work to differentiate motion attributable to the user performing the defined exercise pattern from the overall pattern of motion detected including the background motion; and notifying the user, by means of the alarm, if insufficient or incorrect exercise is detected in order that the defined exercise pattern may be performed to reduce the risk of deep vein thrombosis.
[0035] The step of defining the exercise pattern may include the inputting in to the device by the user of information concerning their lifestyle and body characteristics (age, height, weight etc). This can be used to define a risk profile and so to determine an appropriate exercise pattern.
[0036] After the step of defining the exercise pattern, there may be a further step of placing the device in a calibration mode during which the user performs the defined exercise pattern (possibly but not essentially with minimal background motion). The particular vibration profile associated with the performance of the exercise by the user is detected and stored for use during work when the device is not in the calibration mode.
[0037] At least the step of processing the detected motion is preferably carried out by software stored in the device and running on the processor. This processing is at least a two stage process. The first stage filters the detected motion and dynamically calibrates the sensor to minimise background effects. This feeds motion information that is wholly or predominantly attributable to the activity of the user through to the second stage. The second stage analyses this motion for compliance with the defined exercise pattern in the time period. If this is detected the user is not notified, but if suitable activity is not detected the alarm may be triggered.
[0038] According to the present invention there is yet further provided a device for monitoring the activity of a user working in an office environment, the device comprising a carrier adapted for local attachment on or adjacent a user's leg by means of a releasable attachment device, a motion sensor mounted on the carrier and adapted to detect the user performing a predefined pattern of movement over a preset time frame, a timer mounted on the carrier and connected to the motion sensor so as to be reset should the motion sensor detect the predefined pattern of movement within the time frame, and an alarm also mounted on the carrier and connected to the timer for triggering thereby, should the timer count a preset time period without being reset, wherein the predefined pattern movement and the preset time frame of the timer are such that the alarm is triggered if the limb of the user is not correctly exercised sufficiently frequently to reduce the risk of deep vein thrombosis and wherein all of the components of the device are self contained on the user such that the device is portable within an office environment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] In order that the present invention may be better understood, but by way of example only, various embodiments of the present invention will now be described in more detail with reference to the following drawings, in which:
[0040] FIG. 1 is a simplified block schematic view of one embodiment of device according to the present invention;
[0041] FIG. 2 is a perspective view of further similar embodiment in a form ready for use;
[0042] FIG. 3 is a simplified block schematic view of a further embodiment of device wherein the alarm comprises a low power transmitter; in communication with a remote monitoring station;
[0043] FIG. 4 is a flow chart to demonstrate operation of the embodiment of FIG. 1 ;
[0044] FIG. 5 is an alternative more sophisticated embodiment of the invention;
[0045] FIG. 6 is a flow chart to demonstrate the embodiment of the embodiment of FIG. 5 ;
[0046] FIG. 7 is a simplified view of a motion suitable for use in the present invention; and
[0047] FIG. 8 is a flow chart to demonstrate the operation of a third embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0048] FIG. 1 shows a simple schematic view a first embodiment of the present invention. The device comprises a motion sensor 10 positioned so that it may detect the movement of a user (not shown); a timer 12 connected to the sensor 10 and an alarm 14 . The timer counts down a time period from a preset time t to zero (or up from zero to t), and when it reaches the end it cause operation of the alarm through a controller 16 . The timer 12 and controller 16 are integrated within a processor 17 . In the context of DVT prevention in office workers t may be 56 minutes. The motion sensor is adapted to detect a motion and the processor 17 discerns if the correct motion is detected and when it is detected, the timer 12 is reset to t. A power source in the form of a battery 18 powers the various components. The alarm may take several forms and indeed a device may include several different types in combination. For example a silent vibrating alert might be appropriate for a worker in an office environment to prevent annoyance to others.
[0049] A more practical embodiment of device operating essentially as described with reference to FIG. 1 is shown in FIG. 2 . In this embodiment the motion sensor, battery and processor are housed inside a carrier 20 which can be affixed to a wearer using the straps 22 and 24 . The straps are passed around the leg (if using for DVT prevention) of a user and connected using a two part hook and loop fastener, one part of which 26 can be seen on the inner face of the strap 24 . The carrier 20 is provided on its outer face 28 with an LED 30 which forms part of the alarm, and with an LCD screen 32 indicating operative information about the device such as the time until activation of the alarm or the number of alarm activations.
[0050] The device shown in FIG. 2 is intended for use by a user in an office environment. The device could be strapped to the ankle, leg or waist of a worker using the straps 22 and 24 and the predetermined motion and time period will be set so as to detect regular motion suitable to reduce the chance of the user developing DVT. An example of appropriate exercise might be the tapping of the foot on the floor more than 180 taps in a 3 minute period to cause resetting of the timer. The length of the time period (t) that the timer counts down can vary, but for the prevention of DVT the exercise may comprise 180-240 foot taps in a three to four minutes period and repeated at least every 30 minutes to 1 hour (t=30 to 60 minutes). Dorsiflexion suggests the aforementioned range of taps is sufficient as in use on post operation rehabilitation.
[0051] As long as the wearer performs the correct exercise regularly enough the timer will be reset and the alarm will not sound. Should correct movement NOT be detected then the timer will reach zero and trigger the alarm, thereby reminding the user to make the necessary exercise. The time period and type of exercise can be set by medical recommendation and by the characteristics of the user including height, weight, age and lifestyle.
[0052] The device could also detect other types of exercise that meet the criteria such as walking around and would also reset the counter in response to these. This minimises unnecessary activation of the alarm and prevents annoyance to the wearer. A range of devices could be provided in an office with different preset values. Devices with different preset values could be colour-coded to allow an easy distinction between different types of people. For example, people who could be at greater risk of DVT might be given a device with a shorter time period than those who are at less risk. It is envisaged that these devices with varying preset timing values could be distributed to the users at the commencement of a work period.
[0053] Simple embodiments of the device are automatic and require no adjustment or button pressing from either staff or users, as once they are preset they could literally be handed out. In more advanced versions of the present invention the device can be adapted to define a suitable exercise pattern depending on the information provided by each user.
[0054] The LCD screen 32 could display the number of times the device has been reset by exercise. This information could be logged by the employer manually or automatically and then correlated to the user. This would give the employer a record of a particular employee's compliance with the recommended exercise regime.
[0055] In practice, each user could be given this device and requested to wear it for their safety. Should they refuse or simply not use it then the employer would have complied with the principle of providing as safe as possible a working environment and the onus would shift on to the individual worker.
[0056] A small transmitter could be used in conjunction with the device and this is shown in FIG. 3 . The embodiment of device in FIG. 3 is essentially similar to that shown in FIG. 1 and therefore like parts will be given like reference numerals. The difference between the two embodiments is that the alarm 36 in FIG. 3 includes a transmitter 36 in wireless communication with a receiver at a remote monitoring station 38 . In this way the alarm signal may be transmitted to a remote location for monitoring by a third party. The transmitter could use low power radio waves or ultrasound to communicate with the remote monitoring station.
[0057] FIG. 4 is a flow diagram showing a simplified version of how an embodiment of device might operate. The device is initially attached to a wearer and reset at stage 40 . The timer then begins counting down at step 41 , whilst monitoring movement at step 42 . If movement is detected the type of movement is analysed at step 43 , and the movement associated with exercise is discerned from that attributable to background motion, and if it meets the criteria the timer is reset at stage 40 . If the correct motion is not detected the timer reaches the end of the time period at step 44 , and the alarm is activated at step 45 . The motion sensor continues to monitor for activity at step 46 , and whilst none of the correct pattern is detected, the alarm continues to activate at step 47 . If exercise is detected, it is analysed at step 48 , and if it meets the criteria the timer is reset at stage 40 to restart the cycle. If the exercise is not correct, the alarm will continue to be activated, unless it is manually cancelled.
[0058] The embodiment in FIG. 5 comprises a microprocessor 49 on which driver electronics are run, and to which is fed motion data from the sensor 10 . The sensor also receives feed back calibration information from the processor. An alarm comprising a sounder/vibration motor 14 and an LED 30 are driven by decisions made by software 51 running in the microprocessor 49 . The LED 30 is used to alert the user that the device is functioning properly and also to alert that exercise over at least one period has not been carried out. This is achieved by changing of the LED flash pattern. A battery 50 provides power to the device.
[0059] The flow chart in FIG. 6 shows how the device in FIG. 5 might operate.
[0060] An embodiment of motion sensor suitable for the present invention is shown in FIG. 7 . The sensor comprises a hammer 80 mounted on a base 82 by location of a shaft 84 in an upstanding part 86 . The hammer has a weighted metal contact 88 , which when affected by vibration of significant amplitude completes an electrical circuit with at least one of a contact on the base 82 and a second contact 90 at ninety degrees to the base contact. The hammer is mounted by the shaft 84 which is insulated by an insulation sleeve 92 which covers the hammer shaft.
[0061] A solenoid controlled adjuster 94 is in contact with the hammer shaft 84 . This can be used to adjust the sensitivity of the sensor and to transfer minute hammer movement to a solenoid coil in an adjuster actuator 96 . This provides feedback on resonant and harmonic vibrations to the microprocessor, and the actuator 96 can be used to alter the motion of the hammer in response to the processor's control signals.
[0062] As mentioned above to use exercise to reduce the risk associated with DVT in an office environment the present invention provides the following unique combination of qualities: 1) portable enough to be used in a office without compromising the comfort and safety of the user or fellow workers; 2) detects a specific exercise in a vibration rich environment; 3) can learn the appropriate exercise habits of an individual, calculate, and automatically adjust the exercise regime to reduce an individual's risk; and 4) can adjust its ability to detect exercise as the environment changes.
[0063] To ensure the present invention is portable enough to use in an office setting and not compromise the comfort and safety of the user and fellow workers, the important design factors are: power consumption, processor size, passive component size, battery size, sensor size, motor size, and the manufacturing process.
[0064] The present invention has been tested to run for more than two weeks continuously using battery power. For present requirements, size no longer determines processor power or speed. Because of recent advances in chip design, microprocessors that meet our size, speed, and power requirements are readily available.
[0065] Battery size may preferably be approximately 23 mm diameter and 5.4 mm height. The sensor measures 20 mm in length×6 mm width×16 mm deep. The vibration actuator currently used is 16 mm length×6 mm in diameter. The manufacturing process uses chip on board combined with surface mount components.
[0066] An exercise detection flowchart is shown in FIG. 8 . In normal mode, vibrations of the various types feed through the sensor 10 . The sensor's characteristics tend to filter out the resonant and harmonic vibrations, leaving the exercise (periodic vibrations) and some of the random portion of the vibration picture. This detected motion is feed into the microprocessor 17 , and stage 1 of detection software running on the processor filters this to remove the random portion. The result of this clearly identifies whether the user is active or not and also how well, the sensor is coping with the resonant and harmonic portion of the vibration picture. The software in the processor uses the solenoid coil in the actuator 96 to detect and isolate changes in the vibration picture which are then referenced against the exercise being performed. After the processor finishes polling the actuator 96 it uses the same coil to drive the hammer adjuster 94 to adjust the sensitivity and calibration of the sensor as necessary. This unique twofold use of the actuator allows it dynamically to adjust the sensitivity of the sensor to cope with environmental changes in real time.
[0067] The software has a second stage process that monitors the frequency of the detected movement and compares it with the user's defined exercise profile. The second stage also uses this profile to help filter out any random vibration with amplitude great enough to pass through the stage 1 filter.
[0068] The device has a training mode which allows it to learn the relevant exercise habits of an individual worker and automatically to adjust the exercise regime to reduce their DVT risk. During the initial training mode the worker is asked to perform a series of movements. This data is then used to form part of the user's profile. In an advanced embodiment the user can interact with the device through a user interface such as an LCD screen and buttons. This interaction allows the user to enter information that helps determine their DVT risk. The software combines this with the other data to develop a profile for the user, and thereby to adjust the defined exercise regime appropriately.
[0069] The background motion encountered in an office environment can take various forms and alter continuously during the same work period. The present invention can automatically adjust its ability to detect exercise as the environment changes. This is achieved this by using two-way interactive feedback between the processor and the sensor (see FIG. 8 ). As conditions change, feedback from the actuator allows the sensor to be automatically adjusted which reduces the effects of background motion on the sensor. | A device for monitoring the activity of a user to prevent deep vein thrombosis when working. The device comprises a carrier ( 20 ) for positioning on or adjacent a user, a motion sensor ( 10 ) mounted on the carrier ( 20 ) and adapted to detect the user performing a predefined motion, processor adapted to filter the motion detected to remove background motion not attributable to the desired exercise and to reset a timer ( 12 ) when the predefined motion is detected. An alarm ( 14 ) is operated by the processor should the time period elapse without the exercise pattern being detected. The components are all contained in the carrier ( 20 ) which is preferably a small container that can be attached to a user's trousers or around the limb of a wearer. Failure to undertake the required motion will cause the alarm ( 14 ) to be activated, thus notifying the wearer of the omission. | 0 |
RELATED APPLICATIONS
This application claims benifit of Provisional Application No. 60/532,539, filed Dec. 24, 2003, entitled “Interior Wall Trim System”.
BACKGROUND AND SUMMARY OF THE INVENTION
The present invention provides components and features which enable a non-expert person to install trim assemblies for interior walls in a building such as a house without requiring specialized skills and special equipment.
The present invention enables an unskilled person, such as a homeowner, to install trim assemblies between interior walls and ceilings.
The prior art ordinarily requires a person with certain expertise and utilizing specialized equipment to install such trim assemblies.
Preferred embodiments of the trim assemblies for interior walls and ceilings, include trim strips at opposite sides of a cornerpiece, and a tang extending from respective opposite sides of the cornerpiece into slots in respective trim strips. A block member is disposed at each of the opposite sides of a cornerpiece, and at least one post extends from one or more block members into respective slots in decorative members, and clips to retain the posts in slots to retain decorative members.
Tangs extend oppositely from respective sides of the cornerpiece and into slots in respective decorative strips. The clips are preferably of a T-shaped configuration and have outwardly extending portions to engage in slots to retain the posts.
One or more tangs extend from each block member and into the slots in the cornerpiece. Other tangs extend from each block member oppositely from said first tang members and into slots in respective trim strips at opposite sides of the cornerpiece.
Clip members are disposed at respective posts to retain the posts in respective slots to retain the decorative member.
The block members are preferably secured at an inter-section between a ceiling and walls by clip members on posts extending into slots in the wall.
In embodiments of generally rectilinear arrangements, as about a door or window, a plurality of corner members are disposed at intersections of elongate members.
Each corner member has at least one tang extending from two adjacent sides and into elongate members to attach them together, the elongate members having end portions thereon at least one post extending into a slot in a trim member with clip means to retain the trim member in the slots.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of a preferred embodiment of the invention, as viewed from below, showing the mounting thereof in corners between walls and ceiling;
FIG. 2 is a perspective view of the decorative molding section of FIG. 3 ;
FIG. 3 is a sectional view taken at line 3 — 3 in FIG. 2 ;
FIG. 4 is a sectional view taken at line 4 — 4 in FIG. 1 ;
FIG. 5 is a sectional view taken at line 5 — 5 in FIG. 1 showing a tang component in relation to a slot defined in an adjacent decorative molding section;
FIG. 5A is a sectional view taken at line 5 A— 5 A in FIG. 1 , showing a tang utilized with the invention;
FIG. 6 is a perspective view of a second embodiment of the present invention;
FIG. 7 is a perspective view of a mounting block utilized with the embodiment of FIG. 6 ;
FIG. 8 is an enlarged sectional view taken at line 8 — 8 in FIG. 6 ;
FIG. 9 is a perspective view of a leaf spring component utilized with the invention;
FIG. 10 is an end view of the leaf spring device of FIG. 9 ;
FIG. 11 is an enlarged sectional view taken at line 11 — 11 in FIG. 8 ;
FIG. 12 is an exploded perspective view of a third embodiment of the present invention, viewed from below, showing it mounted between a ceiling and intersecting walls;
FIG. 13 is an elevational view of a door and decorative components and moldings thereon;
FIG. 14 is a perspective view of a corner block and tangs extending therefrom utilized in the embodiment of FIG. 13 ;
FIG. 15 is an enlarged sectional view taken at line 15 — 15 in FIG. 13 ;
FIG. 16 is an enlarged sectional view taken at line 16 — 16 in FIG. 13 ;
FIG. 17 is a perspective view of an outside corner member with tangs extending therefrom;
FIG. 18 is an enlarged sectional view taken at line 18 — 18 in FIG. 17 showing a rounded corner defined by an insertion member;
FIG. 19 is a perspective view of resilient elements on a block; and
FIG. 20 is a view taken at line 20 — 20 in FIG. 19 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings, a preferred embodiment 10 of the invention is shown in FIGS. 1 through 5 . FIG. 1 is a view upwardly toward an intersection 12 between a ceiling 14 and walls 16 , 18 .
A corner member 20 is secured in a corner between walls 16 and 18 , as by a screw 21 , referring to FIG. 4 which extends into the corner defined between the wall 18 and ceiling 14 . The corner member is self-centering during its installation and is readily urged into the corner without fumbling or complications. If there is no wood or other material disposed at the corner to receive a screw, a separate member (not shown) may be positioned behind the intersecting walls to receive the screw.
The corner-piece member has tangs extending therefrom, and typically molded integrally therewith, one pair of spaced-apart tangs 22 , 24 extending from each side of the corner-piece member 20 , as shown. These tangs extend into passages 26 , 28 in the oppositely extending molding sections 30 , 32 . The tangs are T-shaped in cross-section, as indicated in FIG. 5 and FIG. 5A . The outer portion of the tangs may be tapered, as indicated in FIG. 5 , to facilitate entry of the upper portions of respective tangs into the slots or passages 26 , 28 in the molding sections 30 , 32 . Two blocks 34 , 36 are secured to a wall by screws 21 and are adjacent to the opposite sides of the corner-piece member 20 , and are integral with the corner-piece, as shown.
A slot 23 is defined in block portions 34 , 36 in FIG. 1 and at 53 in block portions in FIG. 12 and at 73 in FIG. 6 , into which an end portion of a measuring tape may be retained, as by force-fitting, thus to enable one person to use the measuring tape without requiring a second person to grip and hold the opposite end of a tape.
FIG. 12 shows an alternate embodiment 40 of the invention which is somewhat simpler than the embodiment of FIG. 1 , and somewhat simpler to use and install. FIG. 12 is an exploded perspective view of components according to the invention mounted between a ceiling and intersecting walls. In this embodiment, two blocks 42 , 44 are adjacent respectively to the respective ends of molding sections 46 , 48 , which molding sections are typically 8′–10′ long. The blocks 42 , 44 may be utilized with specially made cornerpiece 51 .
The type of corner member shown will function as an outside corner as well as an inside corner. Tangs 50 similar to those of FIGS. 1 , 5 and 5 A are mounted on the blocks 42 , 44 . The blocks 42 , 44 may have such width or be narrowed as required in particular installations.
Referring to FIG. 12 , each block is slid into one end of the cornerpieces and provides an arrangement similar to that of FIG. 1 . The tangs 50 , 52 on the respective blocks extend into sockets 54 , 56 in the cornerpiece. It may be appropriate to extend the sockets further into the cornerpiece than shown because it may be less expensive to thus provide the sockets.
The tangs on blocks 42 , 44 enter into passages or sockets 57 , 58 in the respective 8′–10′ long molding sections 46 , 48 , the sockets being shown in broken lines at 57 , 58 .
A third embodiment of the invention is illustrated in FIGS. 6 , 7 and 8 . This embodiment includes a cornerpiece similar to that of FIG. 12 . In FIG. 6 , there is shown a block 72 , similar to block 42 of the embodiment of FIG. 12 , and like block 42 has thereon two tangs to engage in slots or passages (not shown) in adjacent molding sections 74 , 76 in the manner in which the tangs of the embodiment of FIG. 1 extend into the passages or slots indicated in FIG. 1 by broken lines. As with FIG. 1 , the molding section is typically 8′–10′ long and comprise decorative molding.
The broken line showings or areas 82 of FIG. 6 represent spaced-apart members like member 70 , which are secured, as by screws, to a wall and attached by posts with leaf springs thereon extending into T-shaped slots such as are shown in FIGS. 9 , 10 and 11 .
FIGS. 8 to 11 illustrate certain components relative to the embodiment of FIG. 6 . Spring components are provided on posts to engage in openings or grooves, in the manner indicated in FIG. 11 . FIGS. 9 and 10 show the leaf spring components 60 in perspective and in sectional views, and a spring component 60 is shown in FIG. 11 engaged about a post 66 engaged in a T-shaped slot 64 , with the leaf spring portions engaging the side walls of the slot to retain member 62 in the slot, as shown. FIG. 11 is an enlarged sectional view taken at line 11 — 11 in FIG. 8 and showing two posts with leaf spring members 60 thereon in relation to T-shaped slots in a molded decorative section. The spring member 60 snaps in place in the T-shaped slot, thus to retain molded sections in place.
The spring members of FIGS. 9 and 10 are mounted on posts 66 and serve to attach the longitudinal molding pieces to block members such as blocks 70 of FIG. 6 which are secured, as by screws, to a wall on which the longitudinal molding pieces are attached.
With T-shaped grooves 80 in the back side of the decorative longitudinal members when mounted, the decorative molding is on the outer side and the T-shaped grooves are on the inner side and secured by the posts 66 and leaf spring members 60 thereon in position.
The leaf spring members 60 may be fabricated of appropriate plastic, and their configuration may differ somewhat from the configuration of FIGS. 9 and 10 .
The decorative moldings must be solidly anchored along their lengths and are supported typically at 16″–24″ intervals along the molding as necessitated by the moldings being fairly flexible, being formed of certain plastics, wood, or other appropriate material.
Referring to FIGS. 13 through 16 , there are shown components according to the present invention which provide decorative molding about a door or a window.
Blocks 90 have pairs of tangs 92 extending outwardly from adjacent sides of the blocks. The blocks are disposed at upper corners of a door and mid-way adjacent the vertical sides of the door. The tangs 92 extend into appropriate openings in an upper decorative member 94 and into vertical members 93 and 95 . The blocks 90 have tangs extending upwardly and laterally to engage outwardly extending decorative strips 96 and vertical strips 93 , 95 .
FIG. 15 , taken at line 15 — 15 in FIG. 13 , shows enlargement of a cross-section of T-shaped slots 98 in a molding and a block 99 having tangs extending from opposite sides thereof, as shown. FIG. 16 shows the engagement of the T-shaped slots 100 of a decorative section, to accommodate posts 102 with spring members thereon.
FIG. 16 shows the utilization of the leaf spring members 60 atop posts 102 and engaged in T-shaped slots 61 to secure a decorative member 106 .
Decorative trim is mounted by blocks 90 on which are mounted a plurality of tangs extending from adjacent sides 90° apart, to engage decorative molded sections 93 , 94 and 95 by engagement of the tangs thereon in passages or slots in respective decorative mold members.
The tangs engage in slots or openings in the decorative sections or members in a manner similar to that in which the tangs of earlier described embodiments engage in corresponding slots or passages to retain decorative mold sections.
FIG. 17 is a view of a corner member 110 with members 112 , 114 extending therefrom and attached by tangs 116 and 118 . FIG. 18 shows an exterior member 110 with block components 112 , 114 attached thereto by tangs 116 , 118 which extend into passages in the decorative molding as in the embodiment of FIG. 1 .
FIG. 18 is a view looking upwardly and is partially in section to show a member 120 of generally triangular configuration with a rounded outer portion or surface. Member 120 fits into a corner, and has a mounting prong or rod portion 122 extending into the corner member, as shown. This arrangement provided by the invention prevents a person or observer, looking upwardly, from seeing any hole or void or rectangular corner. Current house construction tends to eliminate right-angled corners, and instead employ rounded, curvilinear corners.
FIG. 19 shows resilient retainer elements 123 serving the function of the leaf spring members 60 ( FIGS. 9 and 11 ). They are inserted in the T-shaped slot like post 66 in FIG. 11 , the members 123 being urged through the vertical portion of the T-shaped slot 64 , and being compressed in passing through the vertical portion of the T-shaped slot and expanding into the upper transverse portion of the T-shaped slot 64 ( FIG. 11 ), thus to retain the member 66 in the T-shaped slot.
FIG. 20 is a sectional view taken at line 20 — 20 in FIG. 19 . A threaded fastener or screw 21 extends through a passage 21 ′ which is oriented at a substantial angle relative to the screw of the embodiment of FIG. 8 in order to engage member 18 . This arrangement enables the securement of the block 71 , and is utilized in the event there is no substantial material or wood for the securement of a screw at the corner where member 71 is positioned.
It will be understood that various changes and modifications may be made from the preferred embodiments discussed above without departing from the scope of the present invention, which is established by the following claims and equivalents thereof. | A trim assembly for interior walls of buildings has a cornerpiece configured for retention in a corner between intersecting walls, a trim strip extending from each opposite side of the cornerpiece, a tang extending from each opposite side of the cornerpiece and extending into slots in respective trim strips, a block member at each opposite side of the cornerpiece, at least one post extending from at least one of the block members and into a slot in a decorative member, and a clip device disposed about the post to retain it in the slot to retain the decorative member relative to the block member. | 4 |
This Application is a Divisional of U.S. application Ser. No. 09/599,852 of Edward S. HOLT filed Jun. 23, 2000 for APPARATUS CONFIGURATION AND METHOD FOR TREATING FLATFOOT, now U.S. Pat. No. 6,576,018, the contents of which are herein incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to medical devices and, more particularly, to an apparatus and method for treating acquired flatfoot.
2. Description of Related Art
Many adults develop a painful breakdown and deformity of the arch of the foot. Procedures to correct this deformity have required cutting and realigning or fusing bones in the foot.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an apparatus configuration and method for treating acquired flatfoot, while minimizing the need to fuse bones in the foot.
To achieve this and other objects of the present invention, there is method of installing a prosthesis in a foot. The method comprises positioning a first member between a first bone in the foot, and a second bone in the foot, the first member being longitudinal and flexible, such that the first and second bones are separated by a third bone in the foot, and a maximum force in the first member is a tension force when the foot is under a standing load.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of an apparatus for treating flatfoot in accordance with a first embodiment of the present invention.
FIG. 2 is a perspective, partial view corresponding to FIG. 1 .
FIG. 3 is a view of an element of the first preferred apparatus.
FIG. 4A is a view of another element of the first preferred apparatus.
FIG. 4B is a view taken along the line 4 B— 4 B in FIG. 4 A.
FIGS. 5A is a view of yet another element of the first preferred apparatus.
FIG. 5B is a view taken along the line 5 B— 5 B in FIG. 5 A.
FIGS. 6A is a view of yet another element of the first preferred apparatus.
FIG. 6B is a view taken along the line of 6 B— 6 B in FIG. 6 A.
FIGS. 7A is a view of yet another element of the first preferred apparatus.
FIG. 7B is a view taken along the line 7 B— 7 B in FIG. 7 A.
FIG. 8 is a side view of an apparatus for treating flatfoot in accordance with a second embodiment of the present invention.
The accompanying drawings which are incorporated in and which constitute a part of this specification, illustrate embodiments of the invention and, together with the description, explain the principles of the invention, and additional advantages thereof. Throughout the drawings, corresponding parts are labeled with corresponding reference numbers.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1 and 2 show prosthesis configuration 1 including anchor assembly 5 on first metatarsal bone 4 , anchor assembly 25 on heel bone 24 , and cable assembly 70 coupled between anchor assemblies 5 and 25 . Anchor assembly 5 includes backing plate 6 and tube 14 integrally connected with plate 6 . Tube 14 is located in bone through-hole 16 defined in first metatarsal bone 4 . Plate 6 defines a contour that fits a contour of bone 4 , to distribute load transmitted from flexible, metal cable 72 over the surface of bone. In this patent application, the term “cable” means a plurality of filaments or lines attached along the longitudinal dimension by twisting or braiding.
Plate 6 defines holes 7 and 8 . Bone screw 10 is screwed into bone 4 via hole 7 , and bone screw 12 is screwed into bone 4 via hole 8 .
FIGS. 1 and 2 also show fibula bone 50 and other bones 51 .
Anchor assembly 25 includes backing plate 26 and tube 34 integrally connected with plate 26 . Tube 34 is located in bone through-hole 17 defined in bone 24 . Plate 26 defines a contour that fits a contour of bone 24 , to distribute load transmitted from flexible, metal cable 76 over the surface of bone 24 . Plate 26 defines holes 27 and 28 .
Flexible, metal cable 72 is engaged with assembly 5 through tube 14 . Flexible, metal cable 72 has stop 73 fixed to the end of cable 72 . Stop 73 acts as a type of flange to prevent cable 72 from slipping out of tube 14 .
Flexible, metal cable 72 is attached to flexible, metal cable 76 via compressible sleeve 78 . Flexible, metal cable 76 is engaged with anchor assembly 25 via tube 34 .
As shown in FIG. 3, Flexible, metal cable 76 has stop 77 fixed to the end of cable 76 , to prevent cable 76 from slipping out of tube 34 . Cable 76 includes metallic filament 84 and metallic filament 85 . The longitudinal dimension of filament 84 is attached to the longitudinal dimension filament 85 , by twisting.
As shown in FIG. 1, anchor assembly 55 is on navicular bone 22 , anchor assembly 35 is on tibia bone 23 , and cable assembly 90 is coupled between anchor assemblies 55 and 35 . Anchor assembly 55 includes backing plate 56 and curved tube 64 integrally connected with plate 56 . Plate 56 defines a contour that fits a contour of bone 22 , to distribute load transmitted from flexible, metal cable 92 over the surface of bone 22 . Plate 56 defines holes 57 and 58 . Bone screw 60 is screwed into bone 22 via hole 57 , and bone screw 61 is screwed into bone 22 via hole 58 .
Tube 64 is located in curved, bone through-hole 19 defined in navicular bone 22 . Tube 64 has a constant radius of curvature, allowing tube 64 to be guided through through-hole 19 .
Anchor assembly 35 includes backing plate 36 and curved tube 44 integrally connected with plate 36 . Tube 44 is located in bone through-hole 18 defined in tibia bone 23 . Plate 36 defines a contour that fits a contour of bone 23 , to distribute load transmitted from flexible, metal cable 96 over the surface of bone 23 . Plate 36 defines holes 37 and 38 . Bone screw 40 is screwed into bone 23 via hole 37 , and bone screw 42 is screwed into bone 23 via hole 38 .
Flexible, metal cable 92 is engaged with assembly 55 through tube 64 . Flexible, metal cables 92 and 82 share a common tube 64 . Flexible, metal cable 82 has stop 87 fixed to the end of flexible, metal cable 82 . Stop 87 acts as a type of flange to prevent flexible, metal cable 82 from slipping out of tube 64 . Flexible, metal cable 92 has a stop (not shown in FIG. 1) fixed to the end of cable 92 . The stop at the end of flexible, metal cable 92 acts as a type of flange to prevent cable 92 from slipping out of tube 64 .
Flexible, metal cable 92 is attached to flexible, metal cable 96 via compressible sleeve 98 .
Flexible, metal cable 96 and flexible, metal cable 102 share a common tube 44 . Flexible, metal cable 96 is engaged with anchor assembly 35 via tube 44 . Flexible, metal cable 96 has stop 97 fixed to the end of cable 96 . Stop 97 acts as a type of flange to prevent flexible, metal cable 96 from slipping out of tube 44 . Flexible, metal cable 102 has stop 103 fixed to the end of cable 102 . Stop 103 acts as a type of flange to prevent flexible, metal cable 102 from slipping out of tube 44 .
Each cable assembly in the prosthesis is inside of the body, under the skin.
Referring to FIG. 1, the foot is under a load F L of 50 pounds or more as when, for example, the person is standing up. F L , which is a type of standing load, is delivered to the foot via tibia 23 and fibula 50 . Cable assembly 70 extends into metatarsal 4 and heel 24 . Cable assembly 70 defines a length between position 67 on assembly 70 and position 68 on assembly 70 . Cable assembly 70 is positioned and oriented such that a maximum force, on most of this length, is a tension force, meaning that the force is directed along the length of cable assembly 70 . Although pressure from body tissue or bone may cause a force F N perpendicular to cable assembly 70 , on most of the length, F T is greater then F N .
With the load F L , each cable assembly has a tension force that is the maximum force on most of the length of the cable assembly between the two anchor bones of the assembly, as described above in connection with assembly 70 .
Prosthesis configuration 1 is assembled to restore the arch and prevent its future collapse. More specifically, to assemble prosthesis 1 , first make bone through-holes 16 , 19 , 17 , and 18 in metatarsal bone 4 , navicular bone 22 , heel bone 24 , and tibia bone 23 , respectively. Next, attach assembly 5 to bone 4 by placing tube 14 in through-hole 16 , screwing screw 10 into bone 4 via hole 7 , and screwing screw 12 into bone 4 via hole 8 . Attach assembly 25 to bone 24 by placing tube 34 in through-hole 17 , screwing a screw (not shown) into bone 24 via hole 27 , and screwing a screw (not shown) into bone 24 via hole 28 . Attach assembly 55 to bone 22 by placing tube 64 in through-hole 19 , screwing screw 60 into bone 22 via hole 57 , and screwing screw 61 into bone 22 via hole 58 . Attach assembly 35 to bone 23 by placing tube 44 in through-hole 18 , screwing screw 40 into bone 23 via hole 37 , and screwing screw 42 into bone 23 via hole 38 .
Next, pass distal end 75 of flexible, metal cable 72 through tube 14 and pass distal end 79 of flexible, metal cable 76 through tube 34 . Align distal end 75 with distal end 79 and surround distal ends 75 and 79 with compressible sleeve 78 . Compress compressible sleeve 78 to fix the movement of distal end 75 relative to distal end 79 , thereby setting the length of cable assembly 70 . In setting the length of cable assembly 70 , tension cable assembly 70 appropriately to correct the deformity, by pulling the forefoot and heel into a slightly over arched position, such that, when the foot bears load, the proper longitudinal arch is established. Thus, cable assembly 70 extends from heel bone 24 to metatarsal bone 4 , under cuboid bone 20 , navicular bone 22 and talus bone 21 .
In other words, assembly 70 extends into bone 4 and extends into bone 24 . Bones 4 and 24 are separated by bone 20 . Bones 4 and 24 are also separated by bone 22 . Bones 4 and 24 are also separated by bone 21 . Assembly 70 is positioned and oriented such that, in loaded tension, a maximum force is a tension force when the foot is under a standing load.
Pass distal end 99 of flexible, metal cable 92 through tube 64 and pass distal end 93 of flexible, metal cable 96 through tube 44 . Align distal end 99 with distal end 93 and surround distal ends 99 and 93 with compressible sleeve 98 . Compress compressible sleeve 98 to fix the movement of distal end 99 relative to distal end 93 , thereby setting the length of cable assembly 90 . In setting the length of cable assembly 90 , tension cable assembly 90 to correct forefoot abduction. Thus, cable assembly 90 extends from tibia bone 23 to navicular bone 22 on the inboard side of talus bone 21 .
Pass distal end 104 of flexible, metal cable 102 through tube 44 and pass distal end 109 of flexible, metal cable 106 through tube 34 . Align distal end 104 with distal end 109 and surround distal ends 104 and 109 with compressible sleeve 108 . Compress compressible sleeve 108 to fix the movement of distal end 104 relative to distal end 109 , thereby setting the length of cable assembly 100 . In setting the length of cable assembly 100 , tension cable assembly 100 to correct hind foot valgus, to restore heel 24 to neutral alignment. Thus, cable assembly 100 extends from tibia bone 23 to heel bone 24 on the inboard side of talus bone 21 .
Pass distal end 83 of flexible, metal cable 82 through tube 64 and pass distal end 89 of flexible, metal cable 86 through tube 34 . Align distal end 83 with distal end 89 and surround distal ends 83 and 89 with compressible sleeve 88 . Compress compressible sleeve 88 to fix the movement of distal end 83 relative to distal end 89 , thereby setting the length of cable assembly 80 . In setting the length of cable assembly 80 , tension cable assembly 80 to correct forefoot valgus, restoring neutral alignment of the forefoot. Thus, cable assembly 80 extends from navicular bone 22 to heel bone 24 under talus bone 21 .
Thus, flexible, metal cables 76 , 86 , and 106 share tube 34 .
FIG. 4A shows a front view of anchor assembly 5 , and FIG. 4B shows a cross-sectional view corresponding to the line 4 B— 4 B in FIG. 4 A.
FIG. 5A shows a front view of anchor assembly 35 , and FIG. 5B shows a cross-sectional view corresponding to the line 5 B— 5 B in FIG. 5 A.
FIG. 6A is a front view anchor assembly 55 , and FIG. 6B shows a cross-sectional view corresponding to the line 6 B— 6 B in FIG. 6 A.
FIG. 7A shows a front view of anchor assembly 25 , and FIG. 7B shows a cross-sectional view corresponding to the line 7 B— 7 B in FIG. 7 A.
Each of flexible, metal cables 72 , 76 , 92 , 96 , 82 , 86 , 102 , and 106 is 7×19 stainless cable. These cables may also be another flexible material, such as braided SPECTRA or KEVLAR.
In summary, the preferred prosthesis includes flexible cables with end stops already swaged (permanently affixed) in place, anchor assemblies of appropriate shape and fitted with a rigidly fixed (e.g. welded) tube shaped variously for different bones, and compressible metal sleeves. Appropriate bones are drilled to accommodate the tubular portion of the backing plate. The assembly plates are applied to these bones. A flexible cable with end stop has then been passed through each plate and the appropriate cables are connected together with a compressible sleeve under appropriate tension.
With the cables pulled in appropriate tension, a more appropriate anatomic relationship of the foot is established. The patient may be able to bear weight soon after surgery since the device does not depend on healing for its stability.
The backing plates may also include a porous coating on the undersurface of the plate to allow bone ingrowth to the plate.
FIG. 8 shows prosthesis configuration 1 ′ in accordance with a second embodiment of the present invention. Prosthesis configuration 1 ′ including anchor assembly 5 ′ on first metatarsal bone 4 , anchor assembly 25 ′ on heel bone 24 , and cable assembly 70 ′ coupled between anchor assemblies 5 ′ and 25 ′. Anchor assembly 5 ′ includes backing plate 6 ′ and tube 14 ′ integrally connected with plate 6 ′. Tube 14 ′ is located in bone through-hole 16 ′ defined in first metatarsal bone 4 . Plate 6 defines a contour that fits a contour of bone 4 , to distribute load transmitted from flexible, metal cable 72 over the surface of bone 4 .
Anchor assembly 25 ′ includes backing plate 26 ′ and tube 34 ′ integrally connected with plate 26 ′. Tube 34 ′ is located in bone through-hole 17 ′ defined in bone 24 . Plate 26 ′ defines a contour that fits a contour of bone 24 , to distribute load transmitted from flexible, metal cable 76 over the surface of bone 24 . Plate 26 ′ defines holes 27 ′ and 28 ′.
Flexible, metal cable 72 is engaged with assembly 5 ′ through tube 14 ′. Flexible, metal cable 72 has stop 73 ′ fixed to the end of cable 72 . Stop 73 ′ acts as a type of flange to prevent cable 72 from slipping out of tube 14 ′.
Flexible, metal cable 72 is attached to flexible, metal cable 76 via block 115 . More specifically, block 115 defines holes 112 and 114 . Cable 72 is passed through hole 112 and engaged with hole 112 via a mechanism such as a screw, for example. Cable 76 is engaged with hole 114 to adjust the tension of cable assembly 70 ′.
Flexible, metal cable 76 is engaged with anchor assembly 25 ′ via tube 34 ′.
Anchor assembly 55 ′ is on navicular bone 22 . Anchor assembly 55 ′ includes backing plate 56 ′ and curved tube 64 ′ integrally connected with plate 56 ′.
Flexible, metal cable 82 is engaged with assembly 55 ′ through tube 64 ′. Flexible, metal cable 82 has stop 83 ′ fixed to the end of cable 82 . Stop 83 ′ acts as a type of flange to prevent cable 82 from slipping out of tube 64 ′.
Flexible, metal cable 82 is attached to flexible, metal cable 86 via block 117 . Block 117 defines holes 116 and 118 . Cable 82 is passed through hole 116 and engaged with hole 116 via a mechanism such as a screw, for example. Cable 86 is engaged with hole 118 to adjust the tension of cable assembly 80 ′.
Flexible, metal cable 86 is engaged with anchor assembly 25 ′ via tube 34 ′.
Additional advantages and modifications will readily occur to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or the scope of Applicants' general inventive concept. The invention is defined in the following claims. | Disclosed are a prosthesis configuration and method for treating acquired flatfoot. In an exemplary embodiment of the invention, a member is positioned between a first bone in the foot and a second bone in the foot, such that the first and second bones are separated by a third bone, and a maximum force in the member is a tension force when the foot is under a standing load. The member is longitudinal and flexible. | 8 |
TECHNICAL FIELD
[0001] This invention relates generally to a system and method for modifying code assist within an integrated development environment.
BACKGROUND
[0002] Many software programmers utilize integrated development environments (“IDE”) when writing software. An IDE is an editor that allows for compiling, linking, loading, and testing of software within one user interface. The IDE relies upon the development of various plug-ins to extend its capabilities.
[0003] A plug-in is software that enriches a larger piece of software by adding features or functions. For example, a plug-in could be a program that provides online help in the form of hypertext markup language (“HTML”) based on a user's request.
[0004] With the assistance of a plug-in, an IDE is capable of dealing with many different programming languages. One particularly useful programming language is JavaScript. JavaScript is a general-purpose object language for enhancing web pages and servers. JavaScript may be embedded as a small program in a web page that is interpreted and executed by a web client. A scriptor controls the time and nature of the execution, and JavaScript functions can be called from within a web document, often executed by mouse functions, buttons, or other actions from the user. JavaScript can be used to fully control web browsers, including all the familiar browser attributes. It can also be used to build stand-alone applications that can run on either clients or servers.
[0005] JavaScript is an object-oriented programming language. Object oriented programming languages produce reusable portions of programming code known as “objects” that can be combined and re-used to create new programs. The modularity and re-usability of objects will typically speed development of new programs, thereby reducing the costs associated with the development cycle. In addition, if an error is made in defining the object, the error only needs to be fixed in the object, rather than each time an instance of the object appears. By creating and re-using a set of pre-tested, well-defined objects, a uniform approach to developing new computer programs can be achieved.
[0006] A programming language such as JavaScript contains several different default objects. In addition, JavaScript programmers often develop their own objects when writing software. Objects are comprised of methods, properties, and event handlers. In order to remember particular methods, properties and events, a JavaScript programmer will often code assist. Code assist stores default JavaScript objects and allows a programmer to obtain a listing of methods, properties and events.
[0007] The problem with code assist when used with a JavaScript editor plug-in in conjunction with an IDE is that the code assist only includes a predetermined number of default objects, methods, properties and events. A developer can modify or add methods to code assist by embedding the methods in the JavaScript code. This process, however, is inefficient and prone to errors if the developer wishes to reuse the methods in a separate piece of JavaScript code. A system that allows for a developer to add or modify methods without having to continually recreate the methods in the JavaScript code is needed.
SUMMARY
[0008] A system for modifying code assist within an integrated development environment is presented. The system comprises a memory storage for maintaining a user editable external file and database; and a processing unit coupled to the memory storage, wherein the processing unit is operative to modify the user editable external file and the processor is further operable to: initiate the integrated development environment; initiate a JavaScript editor plug-in; receive a request for code assist; parse the user editable external file; store the parsed user editable external file in the memory storage; and display the parsed user editable external file in a window in the integrated development environment.
[0009] A method for modifying code assist within an integrated development environment is provided. The method comprises: maintaining a user editable external file and database; and modifying the user editable external file; initiating the integrated development environment; initiating a JavaScript editor plug-in; receiving a request for code assist; parsing the user editable external file; storing the parsed user editable external file in the memory storage; and displaying the parsed user editable external file in a window in the integrated development environment.
[0010] A computer-readable medium, which records a computer program for modifying code assist within an integrated development environment is provided. The computer program includes: a procedure for maintaining a user editable external file and database; and a procedure for modifying the user editable external file; a procedure for initiating the integrated development environment; a procedure for initiating a JavaScript editor plug-in; a procedure for receiving a request for code assist; a procedure for parsing the user editable external file; a procedure for storing the parsed user editable external file in the memory storage; and a procedure for displaying the parsed user editable external file in a window in the integrated development environment.
[0011] The foregoing background and summary are not intended to be comprehensive, but instead serve to help artisans of ordinary skill understand the following implementations consistent with the invention set forth in the appended claims. In addition, the foregoing background and summary are not intended to provide any independent limitations on the claimed invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The accompanying drawings show features of implementations consistent with the present invention and, together with the corresponding written description, help explain principles associated with the invention. In the drawings:
[0013] FIG. 1 is a screen shot of an exemplary embodiment of a method of modifying code assist
[0014] FIG. 2 is a functional diagram of an integrated development environment with its associated plug-ins.
[0015] FIG. 3 is a block diagram of components of a system for modifying code assist within an integrated development environment.
[0016] FIG. 4 is a flowchart of an exemplary embodiment of a method of modifying code assist.
[0017] FIG. 5 is a diagram of the method in FIG. 4 .
[0018] FIG. 6 is a flowchart of an embodiment of a method of modifying code assist.
DETAILED DESCRIPTION
[0019] The following description refers to the accompanying drawings in which, in the absence of a contrary representation, the same numbers in different drawings represent similar elements. The implementations in the following description do not represent all implementations consistent with principles of the claimed invention. Instead, they are merely some examples of methods consistent with those principles.
[0020] The ability to modify code assist provides an additional tool for software developers utilizing an IDE with a JavaScript plug-in. The tool allows a developer to modify or add existing methods, events, and properties without having to retype the methods, events, and properties in JavaScript.
[0021] FIG. 1 is a screen shot of an integrated development environment with code assist consistent with the present invention. In FIG. 1 , the IDE 100 shown is Eclipse. The Eclipse IDE 100 allows a developer to perform illustrated steps useful in developing a program within one environment. Within the Eclipse IDE 100 , the JavaScript editor plug-in 102 is also active. The JavaScript editor plug-in 102 enables the Eclipse IDE 100 to manipulate JavaScript code.
[0022] In IDE 100 , the developer activated code assist by pressing “.” and entered in the beginning name of the method “document.get.” The JavaScript editor plug-in 102 parsed and stored a user editable external file 108 , named “assist.txt” in this example. The “assist.txt” is a user editable external file that contains methods, events and properties used by the JavaScript editor plug-in 102 . Once the parsed data has been stored in memory, code assist window 104 displays the various methods that are available for “document.get”. The developer may select from the available methods and use the instructions in the code assist window 104 , so that the method is used correctly.
[0023] If the method that the developer desires is not contained within the code assist window 104 , then the developer may edit the external file 108 and restart the Eclipse IDE 100 and the JavaScript plug-in 102 .
[0024] FIG. 2 is a functional diagram of an integrated development environment with its associated plug-ins. In FIG. 2 , Computer 210 contains the operating system 200 and IDE 202 with its associated plug-ins 204 . Computer 210 may be a general purpose computer running a computer program or a specially constructed computing platform for carrying-out the operations described below.
[0025] The IDE 202 communicates with the operating system 200 and is capable of editing, compiling, linking, loading, and testing software. An integrated development environment simplifies the development process for a software programmer by allowing the development of a program to occur all within one environment. The IDE may be implemented in conjunction with any operating system such as Windows, Unix, Linux, or Apple's OS X. An operating system is a computer program that allows multiple simultaneously executing computer programs to interact on one physical computer. The operating system conceals the details of the computer hardware from the program developer. Operating system 200 may operate with IDEs such as Eclipse, Visual Studio, Delphi or JBuilder.
[0026] IDE 202 relies upon plug-ins 204 to enhance its functionality. The plug-ins may be coded in various programming languages, such as Java, C++ or Visual Basic.
[0027] FIG. 3 is a block diagram of components of a system for modifying code assist within an integrated development environment. Computer 210 , having CPU 304 , may transfer data via I/O interface 306 (which can be any conventional interface) by direct connections or other communication links. Computer 210 may also provide a local or remote display 302 .
[0028] Alternatively, Computer 210 can be part of a network such as a telephone-based network (such as “PBX” or “POTS”), a local area network (“LAN”), a wide are network (“WAN”), a dedicated intranet, and/or the Internet.
[0029] Memory device 310 may be implemented with various forms of memory or storage devices, such as read-only memory, random access memory, or external devices. Memory device 310 is able to store instructions forming an operating system 312 and IDE 314 .
[0030] FIG. 4 is a flowchart of a method of modifying code assist consistent with the present invention. A developer modifies a user editable external file containing information, such as methods, events and properties using computer 210 (stage 400 ). The computer 210 may maintain the user editable external file separately from the code that provides the functionality. The user editable external file may comprise a variety of file types, such as text, HTML or extensible Markup Language (“XML”). The user editable external file may be modified by the developer to change existing methods, events and properties. The developer may also add new methods, events and properties to the user editable external file.
[0031] The IDE program is started on computer 210 (stage 402 ). The IDE intersects with plug-ins to edit, compile, link, load and test software.
[0032] The IDE on computer 210 initiates a JavaScript editor plug-in (stage 404 ). The JavaScript editor plug-in enables the IDE to manipulate JavaScript code. As mentioned earlier, JavaScript is an object-oriented programming language. Objects used in JavaScript are comprised of methods, events and properties. Therefore, there is a large amount of information that a developer needs available when coding JavaScript.
[0033] In order to access a listing of the necessary methods, events and properties, a developer uses the JavaScript editor plug-in to request code assist (stage 406 ). Code assist may be requested by, for example, the user pressing the “.” key on the keyboard of computer 210 . Although, the “.” key is used in this example, it should be appreciated that any key or combination of keys may be used to invoke code assist.
[0034] Once the user has initiated code assist, the JavaScript editor plug-in parses the user editable external file and stores it in memory (stage 408 ). The code assist window appears and displays a listing of one or more of the available methods, properties and events (stage 410 ). For example, the developer may narrow the list of displayed available methods by entering the beginning letter of a method. The code assist will then display methods that begin with that letter.
[0035] If the method that the developer is looking for does not exist within the methods displayed, the developer may edit the external file (stage 400 ) and repeat the process, or she may manually enter the method into the IDE.
[0036] FIG. 5 is a diagram of the method in FIG. 4 . In FIG. 5 , IDE 500 contains JavaScript editor plug-in 502 . JavaScript plug-in 502 requests methods from a user editable external file 506 . JavaScript editor plug-in 502 parses and stores the contents of user editable external file 506 in memory. The contents of the parsed user editable external file are then displayed in the code assist window when the user involves code assist.
[0037] FIG. 6 is a flowchart of a method of modifying code assist. A developer modifies a user editable external file containing methods, events, and properties (stage 600 ). The user editable external file may be maintained separately from the code that is needed to provide the functionality. The user editable external file may comprise a variety of file types, such as text, HTML or XML. The user editable external file may be modified by the developer to change existing methods, events or properties. The developer may also create new objects, methods, events or properties.
[0038] The IDE program is started on computer 210 (stage 602 ). The IDE interacts with plug-ins to edit, compile, link, load and test software.
[0039] The IDE on computer 210 initiates a JavaScript editor plug-in (stage 604 ). The JavaScript editor plug-in enables the IDE to manipulate JavaScript code. When the JavaScript editor plug-in is initiated, the developer is able to write JavaScript code. As mentioned earlier, JavaScript is an object-oriented program. Objects used in JavaScript are comprised of methods, events, and properties.
[0040] In order to access a listing of the necessary methods, events and properties, a developer uses the JavaScript editor plug-in to request code assist (stage 606 ). Code assist may be requested, for example, by the user pressing the “.” key on the keyboard of computer 210 . Although, the “.” key is used in this example, it should be appreciated that any key or combination of keys may be used to invoke code assist.
[0041] Once the user has invoked code assist the JavaScript editor plug-in parses the user editable external file and stores it in memory (stage 608 ). The JavaScript editor plug-in is parsed for any new methods, events or properties that were created by the developer in the JavaScript code (stage 609 ). As discussed earlier, a developer is able to embed new methods, events or properties in the JavaScript code. The code assist window appears and displays a listing of the available methods, properties, and events (stage 610 ). For example, the developer may narrow the list of displayed available methods by entering the beginning letter of a method. The code assist will then display methods that begin with that letter.
[0042] If the method that the developer is looking for does not exist within the methods displayed, the developer may edit the external file (stage 600 ) and repeat the process, or she may manually enter the method into the IDE.
[0043] The foregoing description of possible implementations consistent with the present invention does not represent a comprehensive list of all such implementations or all variations of the implementations described. The description of only some implementation should not be construed as an intention to exclude other implementations. Artisans will understand how to implement the invention in the appended claims in many other ways, using equivalents and alternatives that do not depart from the scope of the following claims. Moreover, unless indicated to the contrary in the preceding description, none of the components described in the implementations is essential to the invention. | A system and method for modifying code assist within an integrated development environment. The method comprises: maintaining a user editable external file and database; and modifying the user editable external file; initiating the integrated development environment; initiating a JavaScript editor plug-in; receiving a request for code assist; parsing the user editable external file; storing the parsed user editable external file in the memory storage; and displaying the parsed user editable external file in a window in the integrated development environment. | 6 |
FIELD OF INVENTION
[0001] The present invention relates to in-line air humidifiers and systems using such humidifiers, in particular to in-line humidifiers and systems using same in connection with medical procedures and techniques and more particularly to medical procedures and techniques involving the eye and eye surgery (e.g., retinal tear or detachment surgery).
BACKGROUND OF THE INVENTION
[0002] Retinal tears can occur when the vitreous, a clear gel-like substance that fills the centers of the eye, pulls away from the retina thereby leaving behind a tear or hole in the retina. Rhegmatogenous retinal detachments can result if the retinal breaks, i.e. tears or holes in the retina of an eye are not treated. With retinal breaks, fluid from the vitreous apparently seeps through the retinal break and accumulates under the retina. The degree of detachment is measured by the volume of subretinal fluid as well as the area of the retina involved. Some symptoms of retinal detachment include the presence of floaters, flashes, shadows or blind area, decreased visual acuity and metamorphopsia.
[0003] A number of techniques are employed for treating retinal detachments including using a scleral buckle, pneumatic retinopexy, cryopexy (i.e., freezing) and photocoagulation using a laser or xenon arc light source. These techniques may be used alone or in combination with each other to treat the retinal detachments for example, a combination of using a scleral buckle and photocoagulation. Additional retinal tears with little or no nearby detachment can be treated using photocoagulation or cryopexy.
[0004] In the photocoagulation technique when using a laser, the retinal break is surrounded with one or more rows of a plurality of laser burns or laser heat spots. These laser heat spots or burns produce scars, which prevents fluid from passing through and collecting under the retina. In the photocoagulation procedure, a gas is exchanged for the vitreous fluid being aspirated from within the eye so the gas is intraocular when performing photocoagulation. Typically, the gas is air from a tank that may be filtered and sterilized before it is infused into the eye.
[0005] Such air infusion of into the eye, however, can be quite problematic. For example, the infused air often can cause the lens of a patient's eye to become cloudy and dry, complicating the surgical procedure and creating conditions that can result in injury to the patient.
[0006] It thus would be desirable to have improved devices, systems and methods for infusing a gas, particularly air, to a patient's eye during eye surgery procedures. It would be particularly desirable to have improved devices, systems and methods for infusing air or other gas to a patient's eye during surgery wherein the eye lens remains substantially clear and moist.
SUMMARY OF THE INVENTION
[0007] We have now produced new devices and methods that enable infusing air or other gases into a patient's eye during surgical procedures whereby the eye remains quite clear and moist.
[0008] More particularly, the present invention provides a humidifier device and a system using such a humidifier, in particular a system configured for use in eye surgery, such as retinal tear and/or detachment surgery. The invention also provides related methods for humidifying air and infusing air during eye surgical procedures as well as a method for treating a retinal tear or detachment.
[0009] The methods of the invention in generally comprise providing a humidifier device, humidifying (i.e. adding moisture) to gas via the device and infusing the humidified gas to a patient's eye typically during an eye surgery procedure. The humidifier device is typically in-line, i.e. positioned in a gas flow path between the gas source and the patient's eye.
[0010] Preferred humidifier devices of the invention generally include a housing and a humidifying section disposed within the housing. The housing comprises an inlet and an outlet connection or port that fluidly communicates with the interior of the housing. The humidifying section is located within the housing so air entering the housing via the inlet connection passes through the humidifying section and thence out through the outlet connection, thereby humidifying the flowing air.
[0011] The humidifying section preferably includes material (preferably hydroscopic) that can be hydrated (e.g., initial charged with a liquid, such as a sterile saline solution) and selectively release moisture to the gas as it passes through the humidifying section. Preferably, the material also is a bacteriostatic material. Alternatively, the humidifying section is treated with a germicide or other agent. In general aspects, the humidifying section is any type of reservoir that allows for efficient humidification of the gas flowing therethrough. Also, in general aspects the hydroscopic material includes any one of a number of materials known in the art, including but not limited to cellulose, absorbent synthetic materials, papers including corrugated paper, and the like. Additionally, the humidifying section can have a variety of structural configurations and shapes including a cylinder that permits the passage of air between the inlet and outlet connections. In a particular embodiment, the humidifying section is a cylinder of concentric layers of corrugated paper or other absorbent material configured to maintain a desired shape and integrity of the air flow passage after the corrugated absorbent material has absorbed a desired quantity of liquid. Such a preferred cylinder design is suitably configured to allow the air to flow along the long axis of the cylindrical humidifying section.
[0012] The device housing may be suitably constructed of any one of a number of materials known in the art that is appropriate for the intended use including maintaining structural integrity while being exposed to the humidified air. More particularly, the housing is constructed of a plastic material such as a rigid polypropylene, polyethylene and the like. In a preferred embodiment, the housing includes a visual port or is constructed, at least in part, of a clear plastic material that allows a surgeon or other device user to observe the condition of the hydroscopic material of the humidifying section within the housing.
[0013] In one aspect of the invention, the device housing is constructed to form a one-piece structure in which is disposed the humidifying section. In another aspect of the invention the housing is constructed so as to have two or more members that are releasably secured to each so a single structure is formed when the humidifier is assembled for use.
[0014] A humidifying system of a device of the invention suitably will be in communication with a source of flowing gas (particularly air) and an in-line humidifier as described above. Such a system can further include an air filter that filters the air before it passes through the humidifier. In a more specific embodiment, the filter or system further includes the capability to sterilize the air. The system typically includes tubing that interconnects the various components that form the system. The source of air that flows through the system and is infused into a patient's eye suitably can be a commercially available pressurized tank of air or the like.
[0015] Other aspects and embodiments of the invention are discussed below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] [0016]FIG. 1 is a schematic view of a humidification system according to the present invention.
[0017] [0017]FIG. 2 is a side view of an in-line humidifier according to the present invention.
[0018] [0018]FIG. 3 is an exploded view of an in-line humidifier according to the present invention.
[0019] [0019]FIGS. 4A and 4B are cross-sectional side views of alternative in-line humidifier embodiments according to the present invention.
[0020] [0020]FIG. 5 is a cross sectional view of the humidifying element of FIG. 3 along line 5 - 5 .
[0021] FIGS. 6 A-C are cross-sectional schematic views of an eye undergoing a retinal tear repair procedure while using a humidifying system of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0022] Referring now to the various figures wherein like reference characters refer to like parts, FIG. 1 depicts a preferred system 10 for humidifying air according to the present invention in which air is infused into an eye 2 during, for example a retinal detachment surgical procedure. Although the illustrated system is for infusing air into the eye the system of the present invention is not limited to such a use. It is within the scope of the present invention for such a humidifying system to be used in conjunction with other medical procedures, particularly other surgical procedures involving the posterior segment of the eye and/or phakic fluid/gas exchange, particularly those involving prolonged infusion of a gas.
[0023] System 10 includes gas supply 12 , filter 14 , in-line humidifier 20 and interconnecting tubing 16 . Gas from gas supply 12 (e.g. a pressurized air tank) is communicated by way of the interconnecting tubing 16 to the filter 14 and the filtered gas is communicated via the interconnecting tubing to in-line humidifier 20 . The filtered and humidified gas is then communicated via the interconnecting tubing 16 to a surgical instrument, for example a gas inflow instrument 4 or cannula used in retinal detachment surgery that infuses air into an eye.
[0024] Although generally less preferred, devices of the invention may omit filter element 14 . In such a design, gas from the gas supply 12 is communicated directly to the humidifier 20 by means of the interconnecting tubing 16 .
[0025] The gas supply 12 in an illustrative embodiment is a pressure tank, however, the gas supply can be any of a number of means for storing and distributing a gas into a feed line including a pressure regulated gas supply system. Alternatively, the gas supply 12 can be the gas supply system of a facility or a structure in which the system is located. For example, the gas supply can be the compressed air system in a hospital or other medical facility. In an exemplary use, the gas supply 12 is a source of dry filtered air and more particularly a source of sterile, dry filtered air. The gas being supplied includes air, sulfur hexafluorine, perfluoro propane and any other gas known to those skilled in the art that can be infused into an eye. Typically, the gas is supplied at a pressure sufficient to maintain the shape of the eye without injury, for example between about 0 and 100 mm Hg or more particularly, between about 20-40 mm Hg.
[0026] Filter 14 filters the gas to remove particulate matter and infectious material such as bacteria in the micron and sub-micron range. The filter 14 also is preferably configured to sterilize the gas or air as it passes there through. In an exemplary embodiment, the filter 14 is a MILLEX-GS manufactured by the Millipore Corporation.
[0027] As further shown in FIGS. 2 - 3 , the in-line humidifier 20 includes a housing 22 , having an inlet and outlet connection 26 a, b and a humidifying element 24 disposed therein. As shown in FIG. 2, housing 22 preferably includes at least an area 28 that is translucent or clear so the user can observe the condition of the humidifying element 24 . Alternatively, the entire housing, or a substantial portion of the housing (60%, 70%, 80% or 90% or more of the housing surface area) may be constructed of a translucent or clear material to enable observation of humidifying element 24 .
[0028] In one embodiment as shown in FIG. 2, the housing 22 forms a one-piece structure in which is disposed the humidifying element 24 . In a second embodiment, as shown in FIG. 3, the housing 22 includes two subsections 30 a, b that are releasably secured to each other so as to form a single housing like that shown in FIG. 2 when assembled together. In the illustrated embodiment, one subsection 30 a includes a male threaded connection 32 a and the other section a female threaded connection 32 b to threadably secure the subsections 30 a, b together. The subsections 30 a, b, however, can be configured with other connecting means, e.g., press fit, etc. Preferably, the subsections 30 a, b also are configured so the gas flows through the humidifying element 24 and does not escape the housing 22 .
[0029] The housing's inlet connection 26 a and outlet connection 26 b are any one of a number of suitable connections, e.g. male/female luer lock connections or slip-on tubing connections (e.g., tubing slipped over a spigot). The inlet and outlet connections 26 a, b are arranged so the gas or air flows through the humidifying element 24 in a manner best suited for releasing moisture that is retained in the humidifying element to the flowing gas. In one embodiment, the inlet connection 26 a is disposed in one end cap 34 and the outlet connection 26 b is disposed in the other end cap so the gas passing through the humidifier 10 flows along the long axis of a cylindrical humidifying element 24 . In an alternative embodiment, the end connections 27 a, b are diametrically opposed on the shell of the housing 22 as shown in phantom in FIG. 2.
[0030] Housing 22 is suitably constructed from a variety of materials. For example, plastics will be suitable, preferably rigid materials, such as a polypropylene or high-density polyethylene. Polyfluorocarbons also can be employed such as an extruded teflon housing. Stainless steel or other metal also can be employed, although may be less preferred for cost reasons. Typically, housing 22 is constructed of one or more materials that can be shipped in a sterile condition from a manufacturer to a remote facility (e.g., hospital) for later use.
[0031] Although FIGS. 2 - 3 illustrate the housing 22 as having a generally cylindrical structure with hemispherical end caps (FIG. 2) or truncated conical end caps (FIG. 3) this is not a limitation as the housing can have any of a number of geometrical configurations or shapes or combination of shapes. For example, the housing 22 can be configured using cylindrically shaped members that are joined at an angle to each other so as to form an L-shaped in-line humidifier. The thickness and other details of the housing 22 are established based on the humidity, pressure and flow conditions of the intended use as well as any external forces and/or external environmental conditions (e.g., in situ sterilization and impact loads).
[0032] In a further aspect of the invention, as shown in FIG. 4A, housing 22 can include one or more internal baffle(s) 36 that direct gas flow through the humidifying element 24 and out of the housing. Such an arrangement allows the inlet and outlet connections 26 a, b to be positioned so as to have differing orientations, e.g. positioned so one connection is an end cap 34 and the other connection in the shell of the housing (e.g., orthogonal to each other). Alternatively, the housing 22 includes one or more baffles 36 and the humidifying element 24 comprises two or more sub-sections 25 a, b so the gas makes two or more passes through the humidifying element. As shown in FIG. 4B, with such a design the inlet and outlet connections 26 a, b can be disposed in the same end cap 34 .
[0033] The humidifying element 24 includes a material that preferably can be hydrated and which exhibits good moisture exchanging properties with a flowing gas. The humidifying element 24 also includes a support structure or capability so as to maintain the humidifying element in its desired configuration (e.g., cylindrical) and so the gas can flow therethrough and adsorb moisture from the hydrated material. As such, the humidifying element can include one or more elements to perform the above functions.
[0034] In an exemplary embodiment shown in FIG. 5, the humidifying element 24 includes a plurality of concentric layers 40 that are substantially parallel to the direction of flow of the gas through the housing 22 and the humidifying element 24 . Each concentric layer 40 includes a plain paper sub-layer 40 having a smooth surface and a corrugated paper sub-layer 42 that preferably is attached thereto using any of a number of means known to those skilled in the art. In a more specific embodiment, the plain paper sub-layer 40 and the corrugated paper sub-layer 42 are formed as a continuous sheet and this sheet is wound about a common axis to form the plurality of concentric layers 40 shown in FIG. 5.
[0035] When so formed, the corrugated paper sub-layer defines a plurality of passages 46 that extend along the entire length of the humidifying element and which are open at both ends of the element. The corrugations also maintain sufficient structural rigidity when hydrated so the flow passages 46 remain open and the humidifying element 24 essentially maintains its structural configuration. In this way, the gas can flow along the entire length of the humidifying element 24 through the flow passages 46 and adsorb moisture from the surrounding hydrated paper of both the corrugated paper sub-layer 42 and the plain paper layer 40 .
[0036] The humidifying element 24 also can be constructed from a variety of other materials. For example, the humidifying element 24 can be made of a sheet of flexible plastic foam material, preferably with one surface of which is configured so has to have a plurality of ridges and valleys extending substantially parallel to each other. The ridges and valleys may form, for example, a saw tooth pattern, a square pulse type of pattern or a sinusoidal pattern. The sheet is suitably then wound about itself along a common axis so that the ridges and valleys cooperate to form a plurality of flow passages.
[0037] In general the humidifying element 24 can be any type of reservoir that allows efficient humidification of a gas flowing therethrough. Also, while FIG. 3 depicts a preferred cylindrical shape, humidifying element 24 can be formed in a variety of other designs that would be appropriate for the specific configuration of the housing 22 . For example, the humidifying element can be hexagonal or octagonal in shape. Other physical characteristics of the humidifying element 24 , such as the thickness of the element are established so as to minimize flow and pressure losses, maximize available area for moisture exchange, establish the level of hydration required for use and the physical configuration of the housing.
[0038] In a further embodiment, the humidifying element 24 is treated with a germicide or other agent so as to minimize the potential for infection and the like when the flowing gas is being humidified.
[0039] Suitable dimensions of devices of the invention and the components thereof can vary rather widely and can be readily determined by those skilled in the art based on the present disclosure. In general, the device should have a shape and length so that the device is capable of being employed as an in-line humidifier during eye surgery procedures. Nevertheless, suitable dimensions include the following. The usable length of the housing 22 (length l h in FIG. 1) suitably may be from about 25 to about 50 mm and correspondingly a suitable length for the humidification element 24 (length l f in FIG. 3) maybe from about 20 to about 45 mm. Suitable diameters of the housing 22 (diameter d h in FIG. 1) may be from about 10-25 mm and suitable diameters for the humidification element 24 (diameter d f in FIG. 3) may be from about 9 to about 20 mm. Additionally, the thickness of the housing 22 can be 2 mm or more, more particularly in the range of from about 2 to about 4 mm.
[0040] The use of the humidifier 20 and system 10 of the present invention can be further understood from the following discussion relating to a method for treating a retinal tear or detachment by means of the laser photocoagulation technique and with reference to FIGS. 6 A-C. Reference also shall be made to FIGS. 1 - 3 and 5 for specific components or elements of the in-line humidifier 20 and system 10 of the present invention not otherwise shown in FIGS. 6 A-C.
[0041] In treating the retinal tear or detachment, the user (e.g. medical practitioner) prepares the in-line humidifier 20 and humidification system 10 for use. As such, the practitioner removes the in-line humidifier 20 from its sterile packaging and the humidifying element 24 therein is charged or hydrated with a liquid such as a saline solution. In a more particular embodiment, the humidifying element is hydrated with a sufficient quantity of liquid so it is saturated.
[0042] The humidifying element 24 can be charged or hydrated by alternative methods. In one technique, the nozzle of a syringe or other such instrument containing a predetermined amount of liquid is inserted through either of the inlet or outlet connection 26 a, b and the liquid is injected onto the humidifying element 24 . The amount of liquid to be injected and the rate of injection preferably is established so the fluid hydrates, more preferably saturates, the humidifying element 24 without spillage.
[0043] Alternatively, fluid can be added to the device without disassembly of the device or insertion through the above noted gas flow path inlet/outlets, e.g. fluid can be introduced through a resealable opening or the like in the device. More specifically, a nozzle of the syringe can be passed through a resealable port or grommet 41 in the shell or end cap 34 of the housing. As is known to those skilled in the art, a resealable grommet reseals itself when the nozzle of a syringe is withdrawn. In an exemplary embodiment, 10 ml of saline solution when injected onto a corrugated paper-humidifying element saturated the element.
[0044] In a further technique for hydrating the element 24 , which is particularly applicable to a multi-piece housing (see FIG. 3), the housing 22 is disassembled by means of the threaded connection 32 a, b so the humidifying element 24 can be removed from within the housing. The removed humidifying element 24 is then hydrated by placing or immersing the element in a liquid bath, e.g. a saline solution, until the element is hydrated. Alternatively, a syringe is used to inject the liquid directly onto the humidifying element 24 to hydrate it. As indicated above, the humidifying element 24 (i.e., the hydratable material comprising the element) is preferably saturated. After the element has been hydrated the humidifying element 24 is re-installed in one housing part 30 a and the housing parts 30 a, b are threaded together and re-secured to each other to reform the housing 20 . The element 24 also can be charged or hydrated by other procedures.
[0045] After preparing the in-line humidifier 20 for use, it is interconnected to the other components of the system. For example, the female male Luer-Lok at the inlet connection 26 a receives the male Luer-Lok attached to the interconnecting tubing 16 so as to establish a fluid connection between humidifier 20 and either the filter 14 or the gas supply 12 . Similarly, the male Luer-Lok at the outlet connection 26 b is inserted into the female Luer-Lok provided on the interconnecting tubing 16 being interconnected thereto so as to establish a fluid connection between the humidifier and the cannula 102 that is inserted into the eye 2 .
[0046] In treating a retinal tear or detachment using a photocoagulation technique employing a laser, a cutting/aspirating instrument 100 , a cannula 102 and a light transmitting instrument 104 are inserted through the sclera so one end of each resides intraocular. The light transmitting instrument 104 is configured so the light from the laser (not shown) can be directed to specific locations on the retina The cutting/aspirating instrument is disposed so an end thereof is proximate the retinal tear.
[0047] Initially, the vitreous gel, especially all strands causing traction on the retinal tear are removed or aspirated by means of the cutting/aspirating instrument 100 . As the vitreous gel is being aspirated, the intraocular volume is maintained by a continuous infusion of a fluid, such as a balanced salt solution (BSS), through the cannula 102 . Any subretinal fluid is also aspirated through the retinal tear. Thereafter, the vitreous fluid is aspirated and exchanged with a humidified gas such as air passing through the cannula 102 . In the method of the present invention, the gas or air being exchanged is humidified by means of the in-line humidifier 20 and humidification system 10 as herein above-described.
[0048] The retina surrounding the tear is then repeatedly exposed to the laser light from the light transmitting instrument 104 so as to form a plurality of heat spots on the retina surrounding the retinal tear. In particular, the practitioner manipulates the light transmitting instrument 104 so that a plurality of rows of a plurality of such heat spots surrounds the retinal tear. In this way, the retinal tear is photocoagulated with a laser to achieve a thermal adhesive injury. The heat spots also produce scars that prevent fluid from passing through and collecting under the retina.
[0049] Thereafter, the intraocular gas or air, infused while exposing the retina surrounding the retinal tear to laser light, is totally exchanged for a longer-lasting gas, such as sulfur hexafluorine or perfluoro propane. This gas allows an adequate tamponade time for the therapeutic chorioretinal scar to develop. Preferably, the longer lasting gas being infused is humidified using the in-line humidifier 20 and system 10 of the present invention. After completing the “in eye” portion of the treatment procedure, the inserted instruments and cannula are removed from the eye and the spent or used in-line humidifier 20 is disposed of in accordance with normal and usual practices.
[0050] During the treatment procedure and, in particular when using the humidified gas into the eye, the practitioner, by visual observation through the clear area 28 of the housing 22 , determines if the humidifying element 24 or humidifier should be replaced. For example, the practitioner visually observes the humidifying element 24 through the clear area 28 to see if the element appears to be dried out as a means for making such a determination. If it is determined that the humidifying element 24 is no longer sufficiently hydrated and thus is no longer capable of performing its humidifying function, then the spent in-line humidifier is replaced with a freshly charged or hydrated in-line humidifier.
[0051] For purposes of easily maintaining sterility of the field, the preferred action is to replace the spent element with a new humidifier that has been properly charged with liquid. This course of action also allows a practitioner to prepare a humidifier in advance to minimize the time amount of time required to return the humidified air supply back to service. It is within the scope of the present invention, however, to re-charge the humidifying element 24 of an in-line humidifier 20 that is in use by either injecting additional liquid onto or into the humidifying element or by re-immersing the element in a liquid bath as described above.
[0052] The invention also includes device kits that comprise an in-line humidifier 20 in an assembled configuration with or without interconnecting tubing packaged in a sterile condition. Alternatively, the humidification element 24 and housing 22 can be supplied together in the sterile packaging for later assembly by the practitioner. Preferably the in-line humidifier 20 is provided in its assembled condition.
[0053] Although a preferred embodiment of the invention has been described using specific terms, such descriptions are for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims. | In preferred aspects the invention provides an in-line humidifier, a system using such a humidifier and methods related thereto, a method for infusing a gas into an eye during retinal detachment surgical procedure and a method for treating a retinal tear. The method for infusing gas includes providing an in-line humidifier, humidifying the gas in the in-line humidifier by flowing the gas there through and infusing the humidified gas into the eye. The in-line humidifier includes a housing and a humidifier section disposed within the housing, the humidifier section including a hydroscopic material that releasably retains liquid therein. The housing includes an inlet and outlet connection in fluid communication with the housing interior. The humidifier section is disposed within the housing so the gas entering through the inlet connection flows through the humidifying section, where small quantities of the releasably retinal liquid is released by the hydroscopic material to the flowing gas, and so the humidified gas exits the housing via the outlet connection. | 0 |
FIELD OF THE INVENTION
The present invention relates to burning tables and more specifically to such a table having improved workpiece support and slag removal structure.
BACKGROUND OF THE INVENTION
Burning tables having steel supports such as burn bars or standards for supporting a workpiece in generally horizontal fashion above a water tank and adjacent a torch or similar cutting tool are well-known in the art, and examples of such can be found in U.S. Pat. Nos. 4,341,374; 4,162,060; 3,941,361; and 3,792,846. The steel supports are often easily cut along with the workpiece during cutting operations and require relatively frequent and time-consuming as well as expensive replacement. Complicated fume-extracting equipment is generally required to prevent pollution problems. Although these problems have been reduced somewhat by providing readily removable steel supports with a water surface closely adjacent the supporting surface, the burning tables of the prior art still suffer from several disadvantages. Individual replaceable supports are usually quite large and costly. The supports are usually widely spaced so that smaller cut parts fall below the level of the support surface. Gratings located below the water level between the supports are utilized to catch small pieces of falling metal, but these pieces can be difficult to retrieve and can subject the operator to burns if they are retrieved by hand before being properly cooled. Densely packed supports or supports with large cross-sectional areas are not suitable since blowback of the cutting arc with impeded cutting can occur as the cutting tool moves directly over the support.
The slag and other materials which fall from the workpiece being cut must drop through the water and be periodically removed, and numerous devices for cleaning the bottom of the tanks have been devised, including those discussed in U.S. Pat. Nos. 3,969,132 and 3,770,110. Various arrangements of sloped bottoms and floor with flushing structure such as nozzles or selectively opening and closing drain channels have been suggested, but none of these devices has been entirely satisfactory. The close proximity of the tank bottom to the floor prevents use of a steep incline to cause the slag to settle to one end of the tank.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an improved burning table. It is a further object of the present invention to provide a burning table which overcomes many of the problems associated with prior art burning table structures.
It is another object of the present invention to provide a burning table which has a long-lasting and relatively inexpensive replaceable workpiece supporting structure.
It is still another object of the present invention to provide a burning table which provides for more complete support of all sizes of cut parts than at least most of the previously available tables. It is a further object to provide such a table which also eliminates blowback problems.
It is another object of the present invention to provide a burning table which reduces the pollution from a burning machine without complicated fume-extracting equipment.
It is still a further object of the present invention to provide a burning table with improved structure for collecting slag and for cleaning slag and other material from the bottom of the water tank.
It is another object of the present invention to provide a burning table having a workpiece support structure fabricated from numerous individually reversible and replaceable elements. It is a further object to provide such a table wherein the individual elements are fabricated from common tubing and are substantially smaller and less expensive than at least most previously available replaceable elements.
The burning table constructed in accordance with the teachings of the present invention includes a long-life steel grid supported adjacent the top of a hopper-shaped tank in freestanding fashion for easy removal. Numerous upright copper cylinders or support elements are carried by the steel grid in cutout or castellated areas uniformly spaced along the length and width of the grid. The cylinders, which are fabricated from relatively inexpensive thin-walled copper tubing, extend upwardly from the grid in a compactly spaced pattern to form a crowded material support structure which prevents smaller cut pieces from falling to the grid. The thin cylinder walls prevent blowback problems. The tank is normally filled with water to a level above the level of the grid and slightly below the top of the copper elements so that the elements cool quickly and the slag and other waste material from the cutting operation are quickly received and disintegrate in the water to prevent pollution. The individual copper elements may be reversed end-to-end if one end is damaged during a cutting operation. If an element becomes overly deteriorated, it is simply removed from the grid and replaced with another inexpensive section of copper tubing. Therefore, replacement of expensive burn bars or standards is eliminated and small sections of the burning table surface can be quickly repaired as necessary without undue expense.
The hopper-shaped tank terminates in a lower downwardly sloping vibrating trough which is supported from sloped tank panels by a plurality of resilient fasteners with a flexible seal extending between the panels and the trough. The lower end of the trough opens into a collection bin which has a wire mesh basket supported therein. Vibrators are connected to the panels on either side of the trough and are activated to move the slag into the wire basket. The basket with the slag contained therein may be easily retrieved from the collection bin.
These and other objects, features and advantages of the present invention will become apparent to those skilled in the art from the description which follows and from the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view, partially in section, showing a burning table constructed in accordance with the teachings of the present invention.
FIG. 2 is a perspective view of a portion of the element supporting grid with the elements removed from the supportive surface.
FIG. 3 is a view taken generally along lines 3--3 of FIG. 1 showing in detail the resilient trough-fastener assembly with the flexible seal.
FIG. 4 is a view showing a torch cutting a metal workpiece with slag from the cutting operation entering the water.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A burning table, designated generally at 10 in FIG. 1, includes a supporting frame 12 with legs 13 resting on the work station floor 14. The frame 12 carries a generally hopper-shaped tank 16 having sidewalls 18 and end walls 20 and 22. The bottom of the tank 16 is defined in part by a pair of sloped panels 24 which converge downwardly and inwardly and terminate in upright flanges 26 extending the length of the tank. An elongated trough 30 is resiliently connected to the flanges 26 and slopes downwardly toward the end wall 22 to an opening 32 which opens into a slag collection bin 34. The trough 30 is spaced only a small distance above the floor and therefore the downward slope is quite small.
The sidewalls 18 and end walls 20 and 22 of the tank 16 terminate in a substantially horizontal edge 38. Horizontal load-bearing grid structure 40 is removably supported in freestanding fashion between the sidewalls 18 and end walls 20 and 22 by angles 42 which extend around the inside of the tank, or by other suitable supporting means. As best seen in FIG. 2, the grid structure 40 includes a plurality of first equally spaced bars 44 extending parallel to the length of the tank 16. Transversely extending connecting bars 46 are equally spaced and extend at right angles to the bars 44. The bars 44 and 46 are welded or otherwise suitably connected to each other so that, when viewed from the top, the grid structure 40 defines an open lattice with a plurality of equally spaced rectangular holes 48.
The top of the grid 40, indicated generally at 52 in FIG. 2, is supported slightly below the level of the horizontal edge 38. As best seen in FIG. 2, the bars 44 are notched at locations 54 and the connecting bars 46 are notched at corresponding locations 56 to form castellated or element-receiving areas as indicated generally at 60. The element-receiving areas 60 are uniformly spaced along the grid structure 40 at the alternating intersection points of the bars 44 and 46. The areas 60 therefore are aligned substantially along imaginary lines which extend at an angle of forty-five degrees with respect to the sidewalls 18. However, the grid 40 may be arranged in numerous other patterns which provide a somewhat closely spaced array of element-receiving areas 60.
A plurality of open tubular elements 64 in the shape of a right circular cylinder are received in the areas 60. Preferably the elements 64 are fabricated from copper tubing and include a bottom edge 66 which rests on the bottom of the area 60 and a top edge 68 which extends somewhat above the top 52 of the grid structure 40 and above the level of the horizontal tank edge 38. In the preferred embodiment, the axis of the element 64 is substantially vertical and intersects the juncture of the corresponding bars 44 and 46. The width of the notches 54 and 56 in the bars 44 and 46 are such that the element 64 fits snugly in the receiving area 60 but can be lifted therefrom for replacement or for reversal within the area. In the preferred embodiment, all the element-receiving areas 60 project downwardly substantially the same distance below water level and the copper elements 64 are all of equal height so that the top edges 68 of the elements define a horizontal work supporting area which projects slightly above the edges 38 of the tank 16. The diameter of the element 64 is chosen such that the smallest piece that will be supported on the burning table 10 will not fall into the element. The elements 64 are spaced on the grid structure 40 such that the area between four adjacent elements is approximately equal to the cross-sectional area of the elements 64. It has been found that elements 3" long cut from copper pipe of outer diameter ranging from 2" to 25/8" work satisfactorily, with the preferred outer diameter of the pipe being approximately 21/4". The distance between intersections of the bars 44 and 46 is chosen to be slightly more than approximately two times the pipe diameter. If desired, additional elements 69 fabricated from elements 64 which are cut in half in the axial direction may be placed on the grid 40 at opposite edges of the tank as shown in FIG. 1 to provide more complete supportive structure adjacent the tank sides.
For most cutting operations, the tank 16 is filled with water to a level just above the top of the grid 52 and slightly below the top edge of the elements 64. Preferably, the water level is approximately 1" below the top edge 68. The open lattice arrangement of the horizontal grid structure 40 permits free circulation of the water around both the inside and outside surfaces of the cylindrical elements 64. As best seen in FIG. 4, a metal workpiece 72 is supported on the top edges of the copper elements 64, and a torch 74 of conventional construction is moved along the workpiece to provide the desired cut. Slag, indicated generally at 76, quickly enters the water 78 so that pollution is minimized. The water 78, which is free to circulate in the open ended elements 64 and which is in constant contact with a substantial portion of both the inner and outer cylindrical surfaces of the element provides rapid cooling of the copper to prevent any substantial damage to the element even during slow cutting of a relatively thick workpiece. The notches 54 and 56 are centered on either side of the intersection points of the corresponding bars 44 and 46 so that water may circulate freely and slag 76 may fall freely through the center of the elements 64 and through any one of four equal area sections defined by the intersection of the bottom edge 66 with the upwardly facing ledges, indicated generally at 82 in FIG. 2, of the notched bars. The upright and inwardly facing edges of the notched areas, indicated generally at 84 in FIG. 2, are spaced such that the elements 64 are snugly received therebetween but can be lifted from the element-receiving area 60 if the top edge 68 becomes damaged. The elements 64 can simply be reversed end-for-end so that the edge 68 is inserted into the area 60 and rests upon the ledges 82 and the edge 66 becomes the material supportive portion of the element. The elements 64 are sufficiently long to provide good heat transfer between the copper and the water. Since the elements 64 are fabricated from relatively inexpensive, conventional copper tubing, manufacturing and replacement costs are kept to a minimum. Damaged sections of the supportive surface can be changed quickly and easily, and since the top of the grid 52 is normally maintained at or below water level, no damage occurs to the grid structure 40 during the cutting operation.
The trough 30 includes a substantially flat bottom surface 88 with upright flanges 90 extending upwardly from both edges substantially the entire length of the trough. The trough 30 is wider than the downwardly facing opening defined by the flanges 26 of the sloped panels 24. The flanges 90 extend outwardly of the corresponding flanges 26 and slightly above the lower edge of the flanges 26. The trough 30 is resiliently connected to the sloped panels 24 by a series of connecting assemblies 92 uniformly spaced at intervals of approximately 6" along the flanges. Each connecter assembly 92 includes a bolt 93 which passes through a hole in the flange 26 and through a corresponding hole 94 in the trough flange 90. A resilient spacer 96 extends over the bolt shank between the flanges 26 and 90, and a continuous, U-shaped seal 100 includes side legs supported between the ends of the spacers 96 and the flanges 26 and 90. A nut 102 is tightened on the bolt 94 to compress the side legs of the flexible seal 100 against the ends of the spacer 96. The upwardly opening trough 30 both seals the bottom of the water tank 16 and captures slag and other waste material that falls down through the support elements 64. The bottom surface 88 is sloped downwardly toward the slag collection bin 34 which contains a removable wire mesh basket 106. A vibrator 110 is connected to each of the sloped panels 24 to cause the slag to move down the panels into the trough 30. The vibrators 110 also cause the trough 30 to vibrate and move the slag down the shallow incline to the opening 32 and into the collection bin 34. The collection bin 34 opens upwardly at 108 above the level of the water in the tank, and basket handles 112 extend upwardly to the bin opening so that the operator can easily remove the slag-containing basket 106 from the bin. The entire slag removal operation can therefore be performed without complicated water flushing systems or complex movable parts.
A small water pump (not shown) is provided near the back of the tank for pumping a small portion of the water from the bottom of the tank to the top of the tank and causing enough circulation so that oxide powders and the like from the cutting operation will mix with the water to prevent the powders from floating on the surface.
The grid structure 40 is preferably fabricated from relatively narrow steel bars of approximately 1/4" thickness so that the bottom portions of the cylindrical support elements 64 remain substantially open and allow slag to fall freely therethrough and water to circulate freely to cool the support elements 64. The open support element structure prevents blowback that would hinder the cutting operation. The tubing from which the elements 64 are fabricated has a relatively thin wall on the order of 1/16" thickness to also help reduce blowback problems. The entire grid structure 40 is freestanding on the angles 42 so it may be simply lifted from the table 10 to gain access to the lower portion of the tank 16. A sump pump 122 is provided for moving the water from the tank 16 to a holding tank 124 located at one end of the burning table 10. The water can be removed from the tank 16 without need of a floor drain or other liquid conveying structure. The pump 122 moves the water from the holding tank 124 back into the hopper-shaped tank 16 before cutting operation is resumed. A conventional ball-cock arrangement (not shown) may be provided to maintain the water level just below the top of the cylindrical support elements 64. For plasma arc cutting, the entire arrangement of support elements 64 may be flooded with water, in which case it is necessary to position the top edges 68 of the elements 64 below the level of the tank edges 38.
Having described the preferred embodiment, it will be apparent that modifications can be made without departing from the scope of the invention as defined in the accompanying claims. | A burning table including numerous upright copper support cylinders carried on a load-bearing steel grid to form a horizontal work surface. A high water level provides rapid cooling of the cylinders as the burning tool moves along the surface supported workpiece and eliminates pollution by quickly disintegrating slag. Individual cylinders are reversible in the grid for extended life, and damaged cylinders are easy and inexpensive to replace. The support cylinders are crowded on the grid for complete support of even relatively small parts. A hopper-shaped pan collects slag, and a vibrator causes the slag to move into a collection bin for quick and convenient removal. | 1 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to rotation rate sensors. More particularly, the invention pertains to a method and apparatus for reducing the influence of modulation transition-induced voltage spikes upon the output of an interferometric fiber optic gyro.
2. Description of the Prior Art
In the operation of an interferometric fiber optic gyro (IFOG) an artificial phase difference is routinely superimposed between two counterpropagating light waves by means of a phase modulator. The phase modulation generally alternates in amplitude between ±π/2 radians and the gyro output is sampled at those points, which correspond to the points of maximum measurement sensitivity of the interferometer output to rotation-induced Sagnac phase shifts. Alternative modulation schemes (so-called "overmodulation"), which employ phase modulation depths that may exceed π/2, are sometimes employed that offer other advantages such as improvement in the signal-to-noise ratio.
A square wave modulation waveform in commonly employed for generating the gyro output signal. While such a waveform is readily approximated by the output of present-day phase modulators, the transition between the ±π/2 modulation values is not instantaneous. Rather the so-called square wave output of the phase modulator includes discrete transition periods on the order of 100 nanoseconds during which the modulation assumes a continuum of values between +π/2 and -π/2. This phenomenon is illustrated in FIG. 1, a graphical representation of the square wave output of a gyro phase modulator. As can be seen, while the modulation output essentially shifts between +π/2 and -π/2, over small periods of time Δt the phase modulator imposes all artificial phase differences therebetween. As a consequence, a large portion of the interferometer output intensity range is scanned between these values. Significantly, such range of values includes maximum intensity as well as an infinite number of adjacent values. It is well known that, at zero phase difference, the energies of the two beams counterpropagating within the gyro sensor coil produce total constructive interference, resulting in maxima of the interferometer output characteristic (1+cosθ) where θ is the phase difference between the counterpropagating beams. This same phenomenon occurs at θ=n2π where n is a (positive or negative) integer.
FIG. 2 is a graph of the above-described relationship between interferometer output and phase difference θ. The portion of the intensity-versus-phase difference indicated in bold at 10 illustrates the variation in interferometer output intensity that is "picked up" as the square wave output of the gyro phase modulator momentarily (i.e. over Δt) scans interferometer output in shifting between the points of primary interest, +π/2 and -π/2. The periodic compression of the output scanning process into the periods of very small duration Δt is reflected in the measured gyro output by the so-called "ears" 12 that are found in the intensity-versus-time gyro output characteristic curve as illustrated in FIG. 3. Such ears are periodic and separated in time from one another by τ, the gyro sensor loop transit time. In general, each transition spike in the output intensity results from passage through the maximum point of the intensity transfer function where the phase shifts from one side to the other side of the maximum intensity value.
The periods of the output curve of FIG. 3 between the ears, or output spikes, represent the useful output intensities I i and are determined in part by the rate of rotation of the IFOG around the coil input axis. Under the well-know Sagnac principle, the output of the gyro experiences a phase shift φ in the presence of a rate of rotation about the sensor coil input axis. (Note, even in the absence of rotation rate, ears are present in the output of FIG. 3 resulting from the modulation process itself.) Commonly employed signal processing schemes for extracting rotation rate information from detected signal are based upon synchronous demodulation in which the difference between successive signal levels I i that correspond to ±π/2 modulation intervals is proportional to the measured input rate.
No useful information is obtained during the finite duration of a transition spike in the intensity output (i.e. FIG. 3) of a interferometric gyro. The unavoidable presence of intensity spikes in the output of present day IFOG's produces numerous problems. These are generally related to the electronic operation and performance of the gyro. Typically, present-day IFOG's employ a photodetector to detect the optical output and to generate a corresponding useful electrical signal. The spikes in the optical intensity output produce pulses in the output of the photodetector. Such pulses can decrease gyro accuracy despite the fact that the useful signal between the transition spikes is only sampled after pulse decay. The existence of pulse decay instabilities can adversely affect high accuracy applications as differential rates of decay may introduce rate measurement errors. In addition, the relative amplitude of the transition spike--as opposed to the useful signal--limits the permissible gain of the gyro's front end signal processing electronics as well as the maximum values of front end amplifier feedback resistors. Such limitations increase overall instrument noise, an effect that is particularly evident in the case of very deep values of overmodulation (θ>3π/4). Alternatively, front end saturation can cause significant performance problems as the finite recovery times of the detector and/or front end amplifiers require that the maximum possible values of the feedback resistors of front end gain elements be limited by the amplitudes of the spikes rather than those of the useful signal.
Attempts to minimize the deleterious effects of signal spikes have centered upon processing of the resultant electrical output of the gyro and have included the incorporation of a gate into the signal processing to block photodetector output for the period corresponding to the intensity spike. Such solution is of limited benefit with respect to gyro front end gain. Since the optical intensity signal is received at the photodetector, the problem of saturation of the photodetector and/or front end amplifiers remains. Further, the incorporation of a gate fails to address the errors that result from differing rates of electrical pulse decay.
SUMMARY OF THE INVENTION
The present invention addresses the shortcomings of the prior art by providing, in a first aspect, a fiber optic rotation rate sensor. Such sensor includes a source of optical energy. An optical fiber is formed into a coil located intermediate its opposed ends. Means are provided for dividing the output of the source into two light beams and for launching the light beams into the fiber to counterpropagate within the coil. Means are also provided for imposing a periodic artificial phase difference between the counterpropagating beams of light and for recombining the counterpropagating beams into an optical output signal.
Means are provided for selectively attenuating the optical output signal. A photodetector receives the selectively attenuated optical signal and converts it to a responsive electrical signal.
In a second aspect, the invention provides an improvement in a rotation rate sensor of the type that includes an optical fiber having an internal coiled portion defining an input axis, a coupler for dividing light traveling within the fiber upon entering the coil into counterpropagating beams, a phase modulator for applying a periodic, artificial phase difference between the counterpropagating beams and a photodetector for receiving an optical signal and converting it to an electrical signal. The improvement provided by the invention includes means for receiving the optical output signal and producing a transformed optical signal for application to the photodetector. Such means comprises an electrooptical device.
In a third aspect, the present invention provides a method for detecting rotation rate about a predetermined space axis. Such method is begun by forming a coil having an axis of symmetry interior of an optical fiber. Such axis is then aligned with the predetermined space axis. The output of a source of optical energy is split to form two light beams and such light beams are injected into opposite ends of the optical fiber whereby the beams counterpropagate and interfere within the coil.
Predetermined phase differences are periodically imposed between the counterpropagating beams to modulate them. The modulated optical output of the interfering beams is received and selectively attenuated. The attenuated optical output is converted into a corresponding electrical signal which is then analyzed to determine rotation rate.
The present invention addresses the problems involved with phase modulation transition spikes by attenuating the optical signal in the IFOG during transition intervals. Each transition interval includes the time at which the output intensity reaches a maximum in the absence of the present invention. Attenuation of the intensity of the optical signal reduces the maximum signal reaching the detector during the phase modulation transition period.
Numerous embodiments are provided in accordance with the invention. One method includes attenuating the intensity of the optical signal during transition intervals below that of the useful signal. This way, the values of front end gain feedback resistors are limited by useful signal, rather than the transition spike, amplitude. Of course, any degree of attenuation of the transition spikes is beneficial.
An embodiment of this invention provides apparatus for attenuating the optical signal in an IFOG during transition intervals. An example of such an apparatus is an intensity modulator between the fiber coupler and the photodetector.
The present invention effectively decreases the maximum intensity of the optical signal that reaches the detector during the transition intervals. Any decrease in the maximum intensity results in the corresponding reduction of limitations on the front end gain characteristics of a typical detector. A decrease in the maximum amplitude of the optical signal generated leads also to a decrease in the amplitude of the tail of the electrical signal. In fact, any degree of attenuation of optical signal intensity spiking is beneficial.
An embodiment of the present invention provides an electrical gate in combination with an optical intensity modulator. The electrical gate blocks the electrical output signal as residual transition interval spiking of the optical signal is detected.
A further embodiment contemplates the use of an intensity modulator as an optical switch. Optical signal attenuation is such that the intensity modulator prevents almost all light from reaching the photodetector during the transition intervals. The intensity of the light that reaches the photodetector is dependent upon intensity modulator quality. Examples of appropriate intensity modulators include Mach-Zehnder interferometers and cutoff modulators. Since nearly no light is incident upon the photodetector during transition intervals, the front end gain of the gyro signal processing electronics can be determined from the intensity of the useful signal, rather than that of the intensity spikes.
Various methods and devices may be employed to modulate the intensity of the optical signal. In one embodiment, a discrete cutoff modulator is located between a coupler and the photodetector of the IFOG. Cutoff modulators of 10-20 dB isolation result in received intensity at the photodetector during transition times being less than the useful outputs.
Other objects, features and advantages of the present invention will become apparent from the detailed description that follows. Such description is accompanied by a set of drawing figures. Numerals of the drawing figures, corresponding to those of the written description, point to the various features of the invention. Like numerals refer to like features throughout both the written description and the drawing figures.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram for illustrating ±π/2 square wave modulation for application to light beams counterpropagating within the sensor coil of a fiber optic gyro with transition times Δt exaggerated in duration;
FIG. 2 is a diagram of the intensity-versus-phase shift output characteristic of an interferometer such as that exhibited by the output of the sensor coil of a fiber optic gyro;
FIG. 3 is diagram of the intensity-versus-time output characteristic of a fiber optic gyro for modulation depths greater than zero and less than π radians illustrating the presence of the periodic intensity spikes addressed by the present invention;
FIG. 4 is a schematic diagram of an IFOG in accordance with the invention;
FIGS. 5(a) through 5(d) are a series of waveforms for illustrating the operation of an IFOG in accordance with the invention; and
FIGS. 6(a) and 6(b) are schematic diagrams of alternative embodiments of IFOG's in accordance with the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Turning to the drawings, FIG. 4 is a schematic diagram of an IFOG 14 in accordance with the present invention. A source 16 of optical energy that may comprise, for example, a superluminescent diode (SLD), a laser diode, a superfluorescent source, a light emitting diode (LED) or equivalent means known to those skilled in the art emits optical energy of predetermined wavelength and bandwidth that travels through an optical fiber 18 to a first coupler 20 and then to a polarizer 22. A second coupler 24 receives the output of the polarizer 22, dividing it into a pair of waves that counterpropagate within a coil 26 of optical fiber whose central axis of symmetry coincides with the sensitive or input axis of the gyro 14.
A phase modulator 28 lies within the optical path between the second coupler 24 and the optical fiber sensor coil 26 for applying a periodic artificial phase difference between light waves counterpropagating within the coil 26. Typically, the phase modulator 28 is arranged to apply a square wave function such as that illustrated in FIG. 1. Upon exiting the coil 26, the modulated, counterpropagating waves are combined to interfere at the second coupler 24. The resultant optical intensity signal is of the well-known form 1+cosθ where θ is the phase difference between the interfering light waves. This optical intensity signal propagates back through the polarizer 22 and to the first coupler 20 where a portion of the intensity is coupled to a fiber 29 that directs it to an optical signal attenuator 30. (The representation of the attenuator 30 in the context of the IFOG 14 of FIG. 4 is generic and intended to support the discussion of its basic operation. Specific alternative embodiments of an IFOG in accordance with the invention incorporating specific and distinct optical signal attenuators are illustrated in FIGS. 6(a) and 6(b).) The (optical signal) output of the attenuator 30 is directed to a photodetector 32 for conversion to an electrical signal suitable for electronic signal processing, including electronic gating of any residual modulation transition energy.
The device 30 acts to suppress the deleterious intensity spikes that characterize the interferometric optical signal output of the second coupler 24. FIGS. 5(a) through 5(d) are a series of timing diagrams for illustrating the operation of an IFOG in accordance with the invention. FIG. 5(a), generally corresponding to prior FIG. 1 although of different scale, illustrates the nominal ±π/2 square wave modulation applied by the phase modulator 28. FIG. 5(b), which replicates prior FIG. 3, illustrates the optical intensity-versus-time output of the coupler 20, combining the counterpropagating light beams from the sensor coil 26. The coupler 20 lies, in part, in an optical path between the coil 26 and the photodetector 32. As can be seen, the output signal of FIG. 5(b) is characterized by the inevitable presence of ears or intensity spikes, separated in time by τ, the sensor coil loop transit time (as well as the period of the applied optical phase modulation), whose origin is described above. As discussed, the presence of such intensity spikes in the interferometric optical output signal has been addressed in the past by post-photodetector 32 electronic signal processing techniques. In the invention, by contrast, the device 30 acts upon the optical signal prior to application to the photodetector 32, periodically attenuating the intensity of the optical signal of FIG. 5(b) to remove the intensity spikes prior to "conversion" of the information from the optical to the electrical domain. By thus pre-filtering the harmful and useless portions from the optical signal, the numerous harmful effects that otherwise unavoidably impact upon the electronics of the gyro are avoided. Since significant optical intensity spikes do not become inputs to the photodetector 32, prior art gyro design limitations related to handling of the resultant electrical signal are mitigated. In the case of some applications, such as those dealing with small amplitude optical signals, it will still be advisable to process the electrical signal output from the photodetector 32 by means of electronic gates. However, in contrast with the types of electrical gating apparatus necessitated by prior art arrangements, much smaller and simpler electronic gates are required for use in conjunction with the invention. As a consequence, the saturation issues posed by electronic signal gating in the prior art are much less significant in conjunction with the invention.
Alternative arrangements and embodiments of the invention will be discussed below. However, regardless of the particulars of the embodiment chosen, the resultant functioning of the invention may be described with reference to the timing diagrams of FIGS. 5(a) through (d). FIG. 5(c) is a timing diagram of the electrical signal for driving the optical signal trimming device 30 of the IFOG 14. As is seen, the signal is periodic with a period of τ, the loop transit time. While the signal of FIG. 5(c) is illustrated as a single and pulsed signal, its particular form will vary in accordance with the physical arrangement of the device 30 within an IFOG in accordance with the invention. The particulars of the electrical signal for driving the device 30, in relation to the type of modulator 30 employed, will be well understood by those skilled in the art.
Returning to the timing diagram, FIG. 5(d) presents the optical output of the device 30. This waveform, in contrast to the output of the coupler 24 (the optical signal input to the device 30), is devoid of the intensity spikes that characterize the optical waveform of FIG. 5(b). Rather, the intensity of the waveform of FIG. 5(d) in the regions of the former intensity spikes may, in fact, be less than the useful signal portions intermediate the end points of the loop transit modulation periods. Such periodic diminutions of optical intensity may be achieved in a number of ways in accordance with the type of device 30 employed and its associated principle of operation. Generally, however, it will be understood that the optical signal trimming device 30, whatever its configuration, is electrooptic in nature, acting upon, and causing resultant optical effects in response to a driving electrical input. An electrooptical material, such as LiNiO 3 , provides an essential operative element of such a device.
FIGS. 6(a) and 6(b) are schematic diagrams of alternative embodiments of the invention characterized by different physical arrangements for achieving the required functional operation of the optical signal attenuator 30. As far as other elements of the IFOG are arranged and located, as in the "basic" configuration of FIG. 4 above, such corresponding elements are referred to by like numerals.
The embodiment of FIG. 6(a) employs a so-called cutoff or amplitude modulator as the optical signal attenuator 30. As in the basic configuration, the cutoff modulator is located in the optical path between the first coupler 20 and the photodetector 32. Such location assures that an optical signal of the form of FIG. 3 (or FIG. 5(b)), with undesired intensity spikes, is received at the attenuator 30. The modulator includes a substrate 34 of electro-optically active material such as LiNiO 3 . An elongated internal waveguide 36 is formed of highly-doped LiNiO 3 . Metallized electrodes 38 and 40 are located atop the substrate 34 at opposite sides of the waveguide 36. Such electrodes 38, 40 receive and apply predetermined voltage signals across the waveguide 36, producing electrical fields that control its optical properties (i.e. mode field size). Referring back to FIG. 5(c), the application of such a periodic voltage profile will render the waveguide 36 lossy on a periodic basis. By altering the mode field size of the highly-doped waveguide 36, light travelling through it becomes correspondingly less guided, or unguided, propagating into the substrate 34 rather than passing to the photodetector 32. In effect, the amplitude or cutoff modulator acts as an optical choke in the presence of an appropriate electrical signal. The periodic diminutions seen when one compares the signals of FIGS. 5(b) and 5(d) to one another reflect such operation of a cutoff modulator as the attenuator 30.
The IFOG of FIG. 6(b) employs a Mach-Zehnder interferometer as the optical signal trimming device 30. Again, such interferometer is located between the first coupler 20 and the photodetector 32. The interferometer is formed upon a substrate 42 of electro-optically active material such as LiNiO 3 . An upper waveguide 44 and a lower waveguide 46 are formed of highly doped regions of the substrate 42. The waveguides 44 and 46 meet at input and output Y-junctions 48 and 50, respectively. The input Y-junction 48 splits the input optical signal into two signals that are "regrouped" at the output Y-junction 50. Pairs of electrodes 52, 54 and 56, 58 are located at opposite sides of the waveguides 44 and 46. The interferometer operates by selectively retarding the phase of light passing through one of the waveguides with respect to that passing through the other. By controlling the amount of phase retardation of light traveling through one waveguide with respect to that traveling through the other, one can control the destructive optical interference that takes place at the output Y-junction 50. In the event that, through the imposition of a voltage (or voltages) of sufficient magnitude, a phase difference of ±π radians were to be created between the light traveling through the waveguides 44 and 46, total destructive interference would take place upon recombination at the output Y-junction 50, blanking the optical signal.
As can be seen, both an amplitude modulator and a Mach-Zehnder interferometer may be effectively employed as the optical signal trimming device of an IFOG in accordance with the invention. In either case, a periodic electrical driving signal of the form illustrated in FIG. 5(c) may be employed to reduce the optical signal of FIG. 5(b) that characterizes present day IFOG's to the form of FIG. 5(d). As discussed above, such an optical signal, devoid of so-called ears, is much more suitable for down-line electronic processing than that of FIGS. 3 (or 5(b)). Further, the input of an optical signal of the form of FIG. 5(d) is readily processed and significantly reduces design limitations upon gyro electronics relative to large amplitude transition spikes.
While the benefits of the invention are apparent when described with reference to the processing of the optical output signal of a gyro modulated by the imposition of conventional ±π/2 phase modulation, the apparatus and methods of the invention are equally applicable to IFOG's that employ other periodic modulation schemes. In fact, the benefits of the invention became even more pronounced when applied to an IFOG employing overmodulation (e.g. ±3π/4). In such a case, the intensity of the useful portion of the output optical signal is less than that of ±π/2 modulation. The maxima of the optical signal due to spiking are the same as in the case of ±π/2 modulation. Thus the absolute sizes of the intensity spikes in the case of overmodulation are greater from those for ±π/2 modulation. For this reason, the degradation of accuracy is greater in the case of overmodulation and the benefits of the teachings of this invention are correspondingly even greater.
The embodiments have been described in considerable detail. However, it is to be understood that the invention can be carried out by specifically different methods and devices. Various modifications can be accomplished without departing from the scope of the invention itself. | An interferometric rotation rate sensor is arranged to overcome effects of the unavoidable generation of intensity spikes in the modulated optical output. An electrooptical device is located within the optical path of the sensor for receiving the optical output signal from the sensor coil and transforming it prior to application to the photodetector. The electrooptical device is driven by a periodic electrical signal with a period equal to the loop transit time of light traveling through the sensor coil. By synchronizing the periods of attenuation with the predictable presence of spikes in the optical output, valid optical signal information is preserved while gyro electronics are sheltered from the results of optical intensity spiking. | 6 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of provisional patent application entitled “Method And System For Controlling A Coupling Or Clutch Assembly And Electromechanical Actuator Subassembly For Use Therewith” filed Dec. 10, 2010 and having Ser. No. 61/421,856. This application is a continuation-in-part application of U.S. patent application entitled “High-Efficiency Vehicular Transmission” filed Sep. 6, 2008 and having Ser. No. 12/211,236 which, in turn, claims the benefit of provisional application No. 60/998,773 filed on Oct. 12, 2007.
TECHNICAL FIELD
This invention relates to coupling and control assemblies. This invention also relates to clutch and control assemblies and, in particular, to such assemblies which are electromechanically actuated for use in vehicular automatic transmissions.
OVERVIEW
A one-way clutch (i.e., OWC) produces a drive connection (locked state) between rotating components when their relative rotation is in one direction, and overruns (freewheel state) when relative rotation is in the opposite direction. A typical one-way clutch consists of an inner ring, an outer ring and a locking device between the two rings. Two types of one-way clutches often used in vehicular, automatic transmissions include:
Roller type which consists of spring loaded rollers between the inner and outer race of the one-way clutch. (Roller type is also used without springs on some applications); and Sprag type which consists of asymmetrically shaped wedges located between the inner and outer race of the one-way clutch.
The one-way clutches are typically used in the transmission to prevent an interruption of drive torque (i.e., power flow) during certain gear shifts and to prevent engine braking during coasting. Also, there is a one-way clutch in the stator of the torque converter.
A controllable OWC is an OWC where the lock action can be turned “off” such that it freewheels in both directions, and/or the lock action can be turned “on” such that it locks in one or both directions.
U.S. Pat. No. 5,927,455 discloses a bi-directional overrunning pawl-type clutch, U.S. Pat. No. 6,244,965 discloses a planar overrunning coupling, and U.S. Pat. No. 6,290,044 discloses a selectable one-way clutch assembly for use in an automatic transmission.
U.S. Pat. Nos. 7,258,214 and 7,344,010 disclose overrunning coupling assemblies, and U.S. Pat. No. 7,484,605 discloses an overrunning radial coupling assembly or clutch.
A properly designed controllable OWC can have near-zero parasitic losses in the “off” state. It can also be activated by electro-mechanics and does not have either the complexity or parasitic losses of a hydraulic pump and valves.
Other related U.S. patent publications include: 2010/0252384; 2010/0230226; 2010/0200358; 2009/0255773; 2009/0211863; 2009/0194381; 2009/0159391; 2009/0142207; 2009/0133981; 2009/0127059; 2009/0098970; 2009/0084653; 2008/0223681; 2008/0110715; 2008/0169166; 2008/0169165; 2008/0185253; 20008/0135369; 2007/0278061; 2007/0056825; 2006/0138777; 2006/0185957; and the following U.S. Pat. Nos. 7,806,795; 7,491,151; 7,464,801; 7,349,010; 7,275,628; 7,256,510; 7,223,198; 7,198,587; 7,153,228; 7,093,512; 6,982,502; 6,953,409; 6,846,257; 6,814,201; 6,503,167; 6,193,038; 6,075,302; 4,050,560; 5,052,534; 5,387,854; 5,231,265; 5,394,321; 5,206,573; 5,453,598; 5,642,009; 5,638,929; 5,362,293; 5,678,668; and 5,918,715.
For purposes of this application, the term “coupling” should be interpreted to include clutches or brakes wherein one of the plates is drivably connected to a torque delivery element of a transmission and the other plate is drivably connected to another torque delivery element or is anchored and held stationary with respect to a transmission housing. The terms “coupling,” “clutch” and “brake” may be used interchangeably.
SUMMARY OF EXAMPLE EMBODIMENTS
In one embodiment, an overrunning clutch and control assembly having first and second operating modes is provided. The assembly includes first and second clutch members supported for rotation relative to one another about a common rotational axis. The first and second clutch members have respective coupling faces that oppose each other. The coupling face of one of the clutch members has a pocket. The coupling face of the other clutch member has a locking formation. The assembly further includes a strut received within the pocket in the coupling face of the one clutch member and has an end that is pivotally movable outwardly of the pocket. The assembly still further includes a biasing spring. The assembly further includes an electromechanical apparatus including an actuator mounted for controlled linear reciprocating motion and move in communication with the pocket. The assembly still further includes communication apparatus for wirelessly communicating electrical power from a source of electrical power to the electromechanical apparatus to cause the actuator to linearly move and pivot the strut end against the bias of the spring from a first position which corresponds to the first operating mode to a second position which corresponds to the second operating mode.
The coupling face of the one of the clutch members may be oriented to face axially in a first direction along the rotational axis and the coupling face of the other clutch member may be oriented to face axially in a second direction along the rotational axis.
The biasing spring may bias the strut against pivotal movement of the strut end out of the pocket toward the locking formation of the coupling face of the other clutch member.
The electromechanical apparatus may include a latching solenoid.
The biasing spring may bias the actuator against linear movement towards the locking formation. The strut may be pivotally connected to the actuator.
The first position may be an overrun position. The first operating mode may be an overrun mode. The second position may be a locked position. The second operating mode may be a locked mode.
The assembly may include a sensor for sensing the position of the strut end and providing corresponding feedback information.
In another embodiment, an overrunning clutch and control assembly having first and second operating modes is provided. The assembly includes first and second clutch members supported for rotation relative to one another about a common rotational axis. The first and second clutch members have respective coupling faces that oppose each other. The coupling face of one of the clutch members has first and second pockets. The coupling face of the other clutch member has at least one locking formation. The assembly further includes a first strut received within the first pocket and a second strut received within the second pocket in the coupling face of the one clutch member. Each of the struts has an end that is pivotally movable outward of its respective pocket. The assembly still further includes a first and second biasing springs. The assembly further includes first and second electromechanical apparatus. The first electromechanical apparatus includes a first actuator mounted for controlled linear reciprocating motion and in communication with the first pocket. The second electromechanical apparatus includes a second actuator mounted for controlled linear reciprocating motion and in communication with the second pocket. The assembly still further includes control logic to control the first and second electromechanical apparatus in accordance with a control algorithm. The assembly further includes communication apparatus for wirelessly communicating electrical power from a source of electrical power to one of the first and second electromechanical apparatus selected by the control logic to cause the actuator of the selected electromechanical apparatus to linearly move and pivot a corresponding strut end against the bias of the corresponding biasing spring from a first position which corresponds to the first operating mode to a second position which corresponds to the second operating mode.
The coupling face of the one of the clutch members may be oriented to face axially in a first direction along an axis and the coupling face of the other clutch member may be oriented to face axially in a second direction along the axis.
Each of the electromechanical apparatus may include a latching solenoid.
The first position may be an overrun position. The first operating mode may be an overrun mode. The second position may be a locked position. The second operating mode may be a locked mode.
The corresponding biasing spring may bias the pivoted strut against pivotal movement of its end out of its pocket toward the locking formation of the coupling face of the other clutch member.
The actuator of the selected electromechanical apparatus may be biased by the corresponding biasing spring against linear movement towards the locking formation. The actuator of the selected electromechanical apparatus may be pivotally connected to its respective strut.
The assembly may include a first sensor for sensing the position of the first strut end and providing corresponding feedback information and a second sensor for sensing the position of second strut end and providing corresponding feedback information for controlling the first and second electromechanical apparatus, respectively.
In yet another embodiment, a coupling and control assembly having first and second operating modes is provided. The assembly includes a first coupling member having a pocket. The assembly further includes a second coupling member having a locking formation. The assembly still further includes an engaging member received in the pocket. The engaging member may be engageable with the locking formation. The assembly further includes an electromechanical apparatus having an actuator mounted for controlled linear reciprocating motion and in communication with the pocket. The assembly still further includes communication apparatus for wirelessly communicating electrical power from a source of electrical power to the electromechanical apparatus to cause the actuator to linearly move and move the engaging member from a first position which corresponds to the first operating mode to a second position which corresponds to the second operating mode.
The coupling face of the one of the clutch members may be oriented to face axially in a first direction along an axis and the coupling face of the other clutch member may be oriented to face axially in a second direction along the axis.
The electromechanical apparatus may include a latching solenoid.
The first position may be an overrun position. The first operating mode may be an overrun mode. The second position may be a locked position. The second operating mode may be a locked mode.
The engaging member may be pivotally connected to the actuator.
The assembly may include a sensor for sensing the position of the engaging member and providing corresponding feedback information.
In still yet another embodiment, a coupling and control assembly having first and second operating modes is provided. The assembly includes a first coupling member having first and second pockets. The assembly further includes a second coupling member having at least one locking formation. The assembly still further includes a first engaging member received in the first pocket and a second engaging member received within the second pocket. The engaging members may be engageable with the at least one locking formation. The assembly further includes first and second electromechanical apparatus. The first electromechanical apparatus includes a first actuator mounted for controlled linear reciprocating motion and in communication with the first pocket. The second electromechanical apparatus includes a second actuator mounted for controlled linear reciprocating motion and in communication with the second pocket. The assembly still further includes control logic to control the first and second electromechanical apparatus in accordance with a control algorithm. The assembly further includes communication apparatus for wirelessly communicating electrical power from a source of electrical power to one of first and second electromechanical apparatus selected by the control logic to cause the actuator of the selected electromechanical apparatus to linearly move and move a corresponding engaging member from a first position which corresponds to the first operating mode to a second position which corresponds to the second operating mode.
The coupling face of the one of the clutch members may be oriented to face axially in a first direction along an axis and the coupling face of the other clutch member may be oriented to face axially in a second direction along the axis.
Each of the electromechanical apparatus may include a latching solenoid.
The actuator of the selected electromechanical apparatus may be pivotally connected to its respective engaging member.
The first position may be an overrun position. The first operating mode may be an overrun mode. The second position may be a locked position. The second operating mode may be a locked mode.
The assembly may include a first sensor for sensing the position of the first engaging member and providing feedback information and a second sensor for sensing the position of the second engaging member and providing feedback information for controlling the first and second electromechanical apparatus, respectively.
In yet another embodiment, a clutch and control assembly having first and second operating modes is provided. The assembly includes first and second clutch members that are rotatably supported for rotation relative to one another about a common rotational axis. The first and second clutch members have respective coupling faces that oppose each other. The coupling face of one of the clutch members has a pocket. The coupling face of the other clutch member has a locking formation. The assembly further includes a strut received within the pocket of the coupling face of the one clutch member and has an engaging portion that is movable away from the pocket. The assembly still further includes an electromechanical apparatus including an actuator mounted for controlled linear reciprocating motion and in communication with the pocket. The assembly further includes communication apparatus for wirelessly communicating electrical power from a source of electrical power to the electromechanical apparatus to cause the actuator to linearly move and move the engaging portion of the strut from a first position which corresponds to the first operating mode to a second position which corresponds to the second operating mode.
The coupling face of the one of the clutch members may be oriented to face axially in a first direction along the rotational axis and the coupling face of the other clutch member may be oriented to face axially in a second direction along the rotational axis.
The electromechanical apparatus may include a latching solenoid.
The strut may be pivotally connected to the actuator.
The first position may be an overrun position. The first operating mode may be an overrun mode. The second position may be a locked position. The second operating mode may be a locked mode.
The assembly may include a sensor for sensing the position of the engaging portion of the strut and providing corresponding feedback information.
In still yet another embodiment, a clutch and control assembly having first and second operating modes is provided. The assembly includes first and second clutch members that are rotatably supported for rotation relative to one another about a common rotational axis. The first and second clutch members have respective coupling faces that oppose each other. The coupling face of one of the clutch members has forward and reverse pockets. The coupling face of the other clutch member has at least one locking formation. The assembly further includes a forward strut received within the forward pocket and a reverse strut received within the reverse pocket of the coupling face of the one clutch member. Each of the struts has an engaging portion that is movable away from its respective pocket. The assembly still further includes forward and reverse electromechanical apparatus. The forward electromechanical apparatus includes a forward actuator mounted for controlled linear reciprocating motion and in communication with the forward pocket. The reverse electromechanical apparatus includes a reverse actuator mounted for controlled linear reciprocating motion and in communication with the reverse pocket. The assembly further includes control logic to control the forward and reverse electromechanical apparatus in accordance with a control algorithm. The assembly still further includes communication apparatus for wirelessly communicating electrical power from a source of electrical power to one of the forward and reverse electromechanical apparatus selected by the control logic to cause the actuator of the selected electromechanical apparatus to linear move and move a corresponding engaging portion from a first position which corresponds to the first operating mode to a second position which corresponds to the second operating mode.
The actuator of the selected electromechanical apparatus may be pivotally connected to its respective strut.
The coupling face of the one of the clutch members may be oriented to face axially in a first direction along the rotational axis and the coupling face of the other clutch member may be oriented to face axially in a second direction along the rotational axis.
Each of the electromechanical apparatus may include a latching solenoid.
The first position may be an overrun position. The first operating mode may be an overrun mode. The second position may be a locked position and the second operating mode may be a locked mode.
The assembly may include a forward sensor for sensing the position of the engaging portion of the forward strut and providing corresponding feedback information and a reverse sensor for sensing the position of the engaging portion of the reverse strut and providing corresponding feedback information for controlling the forward and reverse electromechanical apparatus, respectively.
Objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side schematic, sectional view of a dynamic selectable or controllable clutch assembly with an “on-board” solenoid controller or subsystem constructed in accordance with at least one embodiment of the present invention;
FIG. 2 is a block diagram of a one-way electrical power and two-way data communication apparatus of a control method and system constructed in accordance with at least one embodiment of the invention;
FIG. 3 is a sectional perspective view of a latching solenoid for use in the embodiment of FIG. 1 ; and
FIG. 4 is a sectional schematic view of a second embodiment of a latching solenoid “on-board” the clutch assembly of FIG. 1 .
DETAILED DESCRIPTION
As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.
Referring to FIG. 1 , a main controller typically includes motor and engine (i.e., IC Engine or gas motor) controls or control logic which, in turn, performs a number of control functions including a transmission control algorithm. The main controller directly controls a solenoid controller 17 which is “onboard” a clutch or coupling assembly 16 ′. The solenoid controller 17 controls the coupling assembly 16 ′ in response to a control signal from the main controller. Control algorithms for the clutch 16 ′ are portions of an overall transmission control algorithm.
FIG. 1 is a side schematic, sectional view of the dynamic selectable or controllable clutch 16 ′ with “on-board” solenoid controller or system constructed in accordance with at least one embodiment of the present invention. Such dynamic clutches are generally of the type shown in U.S. patent publication 2010/0252384.
The assembly 16 ′ includes an annular pocket member or plate, generally indicated at 34 . An inner axially-extending surface 35 of the plate 34 has internal splines 36 for engagement with a torque transmitting element of a vehicular transmission. An inner, radially-extending face or surface 37 of the plate 34 is formed with spaced reverse pockets 38 in which reverse struts 39 are received and retained to pivot therein about a pivot 45 . One end portion of each reverse strut 39 is normally biased outwardly by a coil spring 48 disposed with an aperture 47 of the pocket 38 . The opposite end portion of each reverse strut 39 is controlled by an actuator in the form of a central domed plunger or push pin 40 of a magnetically latching solenoid, generally indicated at 42 . As indicated in FIG. 3 , the latching solenoid 42 is mounted to the plate 34 within the cavity 64 by a mounting flange 89 which is held on an end housing member 91 by a locking collar 93 . A second end housing member 86 closes the opposite end of solenoid 42 and may include an O-ring for sealing purposes. The solenoid 42 also includes an exterior housing member 99 .
The push pin 40 (which is shown in its fully extended position in FIG. 3 ) together with an armature 92 of the solenoid 42 reciprocate together within the solenoid 42 so that the pin 40 reciprocates, within a passage 43 of the plate 34 . The push pin 40 is supported for reciprocating motion by a Teflon-coated cylindrical member 88 . A locking ring 90 moves with the pin 40 . The member 88 is supported at its opposite ends of the solenoid 42 by members 41 . The armature 92 is positioned adjacent an upper coil assembly 94 , a permanent magnet 96 and a lower coil assembly 98 . The coil assemblies 94 and 98 include coils embedded within a suitable resin 97 . Springs (not shown) preferably bias the pin 40 between its extended and retracted positions. For example, one spring may be located between the ring 90 and one end of the member 88 and a second spring may be located between the other end of the member 88 and the inner surface of the dome of the pin 40 .
The passage 43 communicates the cavity 64 of a frame rail, generally included at 66 , in which the solenoid 42 is housed with the pocket 38 to actuate the opposite end portion of its reverse strut and overcome the bias of its spring. Preferably, at least two reverse struts 39 are provided. One latching solenoid (such as latching solenoid 42 ) is provided for each reverse strut. However, it is to be understood that a greater or lesser member of reverse struts 39 and corresponding latching solenoids 42 may be provided to control the operating mode or state of the clutch 16 ′.
The face or radial surface 37 of the pocket plate 34 is also formed with spaced forward pockets (now shown) in which forward struts (not shown) are received and retained to pivot therein. Like the reverse struts 39 , one end portion of each forward strut is normally biased outwardly by a coil spring (not shown) disposed within an aperture (not shown) of the plate 34 . Each opposite end portion of the forward struts are controllably actuated or moved by an actuating end portion or part of an armature of a forward, magnetically latching solenoid (not shown but substantially the same in function and structure as the reverse magnetically latching solenoid 42 ). The armature of each forward magnetically latching solenoid reciprocates within a passage which communicates its pocket with the cavity in which its solenoid is housed to overcome the bias of its coil spring. Preferably, two forward struts are provided. However, it is to be understood that a greater or lesser number of forward struts may be provided with a forward, magnetically latching solenoid for each forward strut to control the operating state or mode of the clutch 16 . Also, it is to be understood that the end portion or part of each armature may support different types of strut actuators such as pins or springs to move therewith.
As shown in U.S. patent publication No. 2010/0252384 (but not shown in FIG. 1 , but shown at 208 in FIG. 4 ), the assembly 16 ′ may also include a middle plate or element, having a plurality of spaced apertures extending completely therethrough to allow the reverse struts and the forward struts to pivot in their pockets and extend through their corresponding apertures to engage spaced locking formations or notches formed in a radially extending face or surface 48 of a notch plate, generally indicated at 50 . The forward and/or reverse struts engage the locking formations during linear movement of the push pin 40 towards the plate 50 . The forward and/or reverse struts disengage the locking formations during linear movement of the push pin 40 away from the plate 50 under the biasing action of the corresponding forward and/or reverse coil springs.
A snap ring 52 is disposed within a groove 54 formed in an axial surface 56 of the plate 34 to retain the notch plate 50 with the pocket plate 34 . The ring 52 holds the plates 50 , 34 and the middle plate (not shown) together and limit axial movement of the plates relative to one another. An inner axially extending surface 58 of the plate 50 has internal splines 60 for engagement with a torque transmitting element of the transmission 10 ′.
The forward struts lock the notch plate 50 to the pocket plate 34 in one direction of relative rotational movement about an axis but allow free-wheeling in the opposite direction about the axis. The reverse struts perform the same locking function in the opposite direction.
Each solenoid 42 is disposed in its cavity 64 formed in the frame rail 66 . In turn, the frame rail 66 is press fit via dowel pins 68 into the back side or surface 69 of the pocket plate 34 so that the frame rail 66 rotates with the plate 34 . The frame rail 66 houses the solenoid controller 17 and associated electronics 70 for the solenoids within the frame rail 66 . In general, the solenoid controller 17 bi-directionally communicates data from and to the main controller via an interface circuit including rotating and static transformer inductors or coils 74 and 76 , respectively. The coils 74 and 76 also help communicates or couples power from a power source to the latching solenoids.
The frame rail 66 has a second cavity 72 in which the rotating transformer coil 74 is housed to rotate therewith. The coils 74 are electromagnetically coupled to the static coils 76 which are housed in a third cavity 78 formed in an aluminum housing 80 . The housing 80 is grounded or fixed to the transmission housing by splines 82 formed on an axially extending exterior surface 84 of the housing 80 . The main controller sends both modulated and unmodulated power signals to the static coils 76 which, in turn, induces corresponding signals in the rotating coils 74 across the gap between the rotating frame rail 66 and the fixed housing 80 .
The solenoid controller 17 converts the AC power signals to DC power signals downstream of the rotating coils 74 to induce current in selected ones of the solenoids 42 under control of the controller 17 . The controller 17 and associated electronics 70 split the signals and directs the signals to separately control the brake side and drive side of the OWC 16 ′ (independent control and actuation of the reverse and forward struts via the latching solenoids 42 ). The controller 17 and the electronics 70 also act as a communication bus for the control data or signals to and from the main controller and the rotating clutch 16 ′. Examples of what are communicated are:
Send a signal to the main controller verifying “OFF” and “ON” positions (feedback signal) generated from a position sensor or transducer 90 disposed within the pocket plate 34 adjacent the strut 39 within or immediately adjacent the pocket 38 . The position sensor 90 may include an electromagnetic coil or inductor embedded within or surrounded by a suitable resin and disposed within a coil housing. The resulting sensor 90 is disposed within a cavity formed in the plate 34 or in the pocket 38 in which the strut 39 is located. The coil is energized by a DC voltage by the microprocessor to generate a magnetic flux which, as long as the strut 39 is in the pocket 38 , flows through the coil housing, through a portion of the strut 39 and across the small air gaps between the coil housing and the strut 39 . When the strut 39 pivots out of the pocket 38 , the magnetic flux is broken which condition is sensed by the microprocessor. In this way, the states or positions of the struts 39 are monitored by the microprocessor.
The OWC 16 ′ goes “OFF” when there is a loss of power in the system. A signal is sent to the clutch 16 ′ saying power is “ON”. If that signal fails, one or more capacitors (which are typically maintained charged) in the electronics 70 fire into the coils 94 and/or 98 of the solenoids 42 and latch the solenoids 42 in their “OFF” position.
The control system has the capability to communicate control data and feedback signals using the same circuit (i.e., the controller 17 and the electronics 70 ) by which power is delivered to the solenoids 42 (i.e., the frame rail 66 may be modified to add sensors/the electronics 70 /the controller 17 ).
The solenoid controller 17 may comprise a programmed microprocessor to control initialization and strut actuation, preferably by directly or indirectly controlling current supplied to the solenoids 42 in the form of pulses which function as drive signals for the solenoids.
The various components or functions of controller 17 may be implemented by a separate controller as illustrated, or may be integrated or incorporated into the vehicular transmission or the main controller, depending upon the particular application and implementation. The solenoid controller 17 may include control logic to control the AC signals and one or more switching devices (such as transistors) to selectively store and recover energy from one or more energy storage devices (such as capacitors) and/or to selectively provide a start-up control switch. Control logic which may be implemented in hardware, software, or a combination of hardware and software, then controls the corresponding strut actuator(s) to implement the solenoid control algorithm.
Transfer of Electrical Power
Referring now to FIG. 2 , there is shown a one-way electrical power and two-way data communication apparatus of the preferred embodiment of this invention, coupled to a main controller and a source of electrical power. The apparatus is generally of the type described in U.S. Pat. No. 5,231,265. Specifically, the apparatus includes the inductors or coils 74 and 76 , a modulator and power driver circuitry, a demodulator, a rectifier, latching solenoids and position sensors, a data recovery and voltage regulator circuit, a switching and latching circuit and a microprocessor. The modulator and power driver circuitry is coupled to the electrical power source and to the main controller. The modulator and power driver circuitry transfers the electrical power signal from the source to the inductor 74 which, in turn, transfers the electrical power signal to the inductor 76 by means of magnetic flux between the inductors 74 and 76 . Thereafter, the inductor 76 couples the received electrical power signal to the rectifier. The rectifier is coupled to each of the latching solenoids 42 contained within each of the cavities 64 and acts to transfer this received electrical power to a latching solenoid 42 selected by the microprocessor. Additionally, the output of the rectifier is input into a voltage regulator which produces a DC output voltage at a level which is required by the microprocessor.
Upon receipt of the electrical power signal from the inductor 74 , the inductor 76 outputs this electrical signal to the rectifier which rectifies the received AC electrical power signal to obtain a DC signal which is controllably coupled to each of latching solenoids disposed within each of the cavities 64 . While this power is coupled to the individual latching solenoids, none of the electrical power flows therethrough due to the field effect transistors of the switching and latching current. That is, each of the individual latching solenoids 42 is coupled to a unique field effect transistor. The output of the rectifier is then applied and flows through its individual latching solenoid 42 only when its uniquely associated field effect transistor is enabled or is activated by the microprocessor. If the individual field effect transistor associated with a particular latching solenoid 42 is disabled, then the flow of electrical power to that individual latching solenoid 42 is blocked or prevented and, consequently, that latching solenoid 42 is not energized.
The microprocessor is coupled to each of the field effect transistors and to the position sensors 90 which sense the position of the struts 39 . The position sensors 90 are deployed within the frame rail 66 so as to generate a signal representative of the position of the struts 39 actuated by each of the latching solenoids 42 . The position signals are downloaded to the microprocessor, where they are stored by the microprocessor and later output therefrom.
Two-Way Data Communication
The modulator and power driver circuitry has an input which receives control data from the main controller. The electrical power signal received by the circuitry (from the power source) is modulated by the control data from the main controller. A tuned circuit in the circuitry has a resonant frequency. The resonant frequency provides an efficient transfer of electrical power to the latching solenoids from the electrical power source. When it is desired to transmit control data from the main controller 12 to the latching solenoids, the control data is transmitted to the circuitry. The circuitry causes a signal to be produced in the inductor 74 which comprises a variation or a modulation of the electrical power signal according to the control data. After such control data is sent, the circuitry then transfers electrical power to the inductor 76 (via the inductor 74 ) which is substantially un-altered or unmodulated. That is, the electrical power signal from the power source is initially varied according to the control data received from the main controller. In this manner, control data may be transmitted from the main controller to the microprocessor without the need for a physical connection therebetween or some sort of additional communication apparatus.
Not only is electrical power transferred to the individual latching solenoids in the form of pulses (for purposes of activating these solenoids), but the same electrical power signal is modified or varied according to control or feedback data which is desired to be sent to the microprocessor from the main controller. In this manner, the solenoids and the solenoid controller may be deployed in an inaccessible place (since no physical connections between the solenoid controller and main controller are necessary) making the solenoid controller much more adaptable to various situations while maintaining simplicity in overall design.
When an individual field effect transistor activates its associated latching solenoid a load is reflected to the inductor 74 by means of the flux communication between the inductor 76 and the inductor 74 . By periodically activating and deactivating the field effect transistor, the programmed microprocessor causes a variation in the flux between the inductors 74 and 76 . This flux occurs and/or exists because of the aforementioned transfer of electrical power between the inductors 74 and 76 . This variation in the flux is used in the preferred embodiment of the invention, to send feedback data from the solenoid controller to the main controller via the demodulator. This feedback data is transmitted to the main controller by the selective activation and deactivation, of one of the field effect transistors by the microprocessor. In this manner feedback data such as strut position data may be transferred, from the position sensors 90 to the solenoid controller and then to the main controller, without the need for physical connection between the solenoid controller and the main controller.
Referring now to FIG. 4 , there is shown a second embodiment of a latching solenoid 142 for controlling a coupling or clutch assembly. The coupling or clutch assembly includes an annular notch plate or member 250 having at least one locking formation 206 formed thereon and an annular pocket member or plate, generally indicated at 234 . An inner axially-extending surface of the plate 234 has internal splines for engagement with a torque transmitting element of a vehicular transmission. An inner, radially-extending face or surface of the plate 234 is formed with spaced reverse pockets 238 in which reverse struts 239 are received and retained to pivot therein about a pivot 204 which pivotally connects an end portion 210 of an actuator 140 to the strut 239 . The opposite end portion of the actuator 140 is normally biased to the left by a coil spring 200 disposed between a ring 190 mounted on the actuator 140 and an end portion of a cylindrical member 188 . An engaging portion of each reverse strut 239 is controlled by the actuator 140 which has the form of a domed plunger or push pin of a magnetically latching solenoid, generally indicated at 142 . As indicated in FIG. 4 , the latching solenoid 142 is mounted to an apertured plate 218 within the cavity 64 by a mounting flange 189 which is held on an end housing member 191 by a locking collar 193 . Mounting members 214 extend through apertures 212 formed through the flange 189 and are secured to locking formations 216 on a surface of the plate 218 . Another apertured plate 220 may be used to secure the plate 218 to the plate 234 . A second end housing member 186 closes the opposite end of solenoid 142 and may include an O-ring for sealing purposes. The solenoid 142 also includes an exterior housing member 199 .
The push pin or actuator 140 (which is shown in its fully extended position in FIG. 4 ) together with an armature 192 of the solenoid 142 reciprocate together within the solenoid 142 so that the pin 140 reciprocate within a passage 243 of the plate 234 . The push pin 140 is supported for reciprocating motion by Teflon-coated inner surface of the cylindrical member 188 . The locking ring 190 moves with the pin 140 . The member 188 is supported at its opposite ends of the solenoid 142 by members 141 . The armature 192 is positioned adjacent an upper coil assembly 194 , a permanent magnet 196 and a lower coil assembly 198 . The coil assemblies 194 and 198 include coils embedded within a suitable resin 197 . Springs 200 and 202 bias the pin 140 between its extended and retracted positions. For example, the spring 200 is located between the ring 190 and one end of the member 188 and the spring 202 is located between the other end of the member 188 and the inner surface of the dome portion 210 of the pin 140 .
The passage 243 communicates the cavity 64 of a frame rail, generally included at 66 , in which the solenoid 142 is housed with the pocket 238 to actuate the end portion of its reverse strut 239 and overcome the bias of the spring 200 .
While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention. | An electromechanically actuated coupling and control assembly is provided. In one embodiment, an overrunning clutch and control assembly having first and second operating modes is provided. The clutch and control assembly includes first and second clutch members supported for rotation relative to one another about a common rotational axis. The first and second clutch members have respective coupling faces that oppose each other. The coupling face of one of the clutch members has a pocket. The coupling face of the other clutch member has a locking formation. The assembly further includes a strut received within the pocket in the coupling face of the one clutch member and has an end that is pivotally movable outwardly of the pocket. The assembly still further includes a biasing spring. The assembly further includes an electromechanical apparatus including an actuator mounted for controlled linear reciprocating motion and in communication with the pocket. The assembly still further includes communication apparatus for wirelessly communicating electrical power from a source of electrical power to the electromechanical apparatus to cause the actuator to linearly move and pivot the strut end against the bias of the spring from a first position which corresponds to the first operating mode to a second position which corresponds to the second operating mode. | 5 |
CLAIM OF PRIORITY
[0001] This application claims priority to U.S. Provisional Patent Application No. 61/708,749, filed Oct. 2, 2012, the contents of which are hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention relates generally to cryogenic delivery systems and methods and, in particular, to a cryogenic liquid delivery system and method with active pressure building capabilities.
BACKGROUND
[0003] This invention relates to a delivery system and method of a cryogenic fluid, such as liquefied natural gas (LNG), from a storage tank to a use device, such as a natural gas powered vehicle engine. An embodiment of the system of the invention is particularly suited for markets in which pre-saturation of the LNG fuel is not performed, though it may also function as a source of “trim heat” if the tank pressure falls below a pre-defined level.
[0004] Many heavy-duty vehicle engines require that the intake pressure of natural gas be around 100 psig. In most markets, LNG is saturated, or heat is added, to a point at which its vapor pressure is roughly equal to the pressure required b the use device. This process of building saturation pressure is typically performed at LNG fueling stations. However, there exist some markets in which this saturation of the fuel before transferring it to the vehicle storage tank is not performed or is not performed to an extent great enough to achieve 100 psig saturated liquid in the vehicle tank after fueling. Thus, the storage tank may end up being filled with LNG well below the desired pressure.
[0005] One proposed method for building tank pressure is to utilize a pressure building circuit that is common on many stationary cryogenic cylinders. These circuits function by utilizing gravity to feed liquid cryogen into a vaporizer. Upon vaporization of the liquid, its volume expands and the evolved gas is routed to the vapor space above the cryogen, building a head of vapor pressure above the liquid phase in the tank. However, there are three distinct problems with this type of circuit for LNG vehicle tanks. First, as most LNG vehicle tanks are mounted horizontally, there is small liquid head pressure compared to a vertical tank to force liquid into the vaporizer. Second, since LNG vehicle tanks are used M mobile applications, any vapor pressure that is built above the liquid phase will quickly collapse as soon as the vehicle is in motion and the liquid and vapor phases mix. It may take several hours or more to add enough heat in this fashion to fully saturate the bulk of LNG in the tank. Third, because pressure building coils are gravity feed systems, the feed line is directly connected to the liquid space. In a vehicle accident, this open liquid line can be damaged, creating a fire hazard due to the large volumes of gas generated from a liquid leak.
[0006] Another proposed solution is referenced in U.S. Pat. No. 5,163,409 to Gustafson et at whereby compressed natural gas (CNG) is used to add vapor pressure above LNG to deliver the fuel at an elevated pressure. However, this solution requires a second tank for CNG be mounted on the vehicle, which would add weight and occupy space on the vehicle chassis.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a schematic view of a prior art ENG delivery system;
[0008] FIG. 2 is a schematic view of an embodiment of the delivery system of the invention;
[0009] FIG. 3 is an enlarged schematic view of an embodiment of the flow inducing device of the delivery system of FIG. 2 ;
[0010] FIG. 4 is a schematic view of an embodiment of a controller for activating the flow inducing device of FIGS. 2 and 3 ;
[0011] FIG. 5 is a schematic view of a multiple cryogenic tank system in an embodiment of the delivery system of the invention.
DETAILED DESCRIPTION OF EMBODIMENTS
[0012] While the invention is described below in terms of liquid natural gas (LNG) as the cryogenic liquid, it is to be understood that the invention is not so limited and may be used with other types of cryogenic liquids in other applications.
[0013] The LNG delivery system described below overcomes the aforementioned shortcomings of the prior art by including a compressor or pump situated on a parallel path downstream of the vaporizer to actively force natural gas vapor hack into the vehicle fuel tank, adding heat to the tank at a rate that far exceeds that which could be accomplished by passive systems. Compressor operation is controlled by a control system that monitors the system pressure, turning the compressor on when system pressure is low and of when the system pressure reaches a predefined point. Once the liquid is saturated, the LNG delivery system functions as the system described in commonly owned U.S. Pat. No. 5,421.161 to Gustafson, the contents of which are hereby incorporated by reference.
[0014] FIG. 1 depicts the fuel delivery system in the '161 patent and a brief description is included here for clarity. A cryogenic tank 22 contains cryogenic product such as LNG consisting of liquid cryogen 26 with a vapor filling the tank vapor space or head space 36 above it. Liquid line 24 communicates with the bottom of tank 22 where liquid 26 is contained, Product withdrawal line 28 connects liquid line 24 to the gas use device such as a vehicle engine. A heat exchanger or vaporizer 32 is located in withdrawal line 28 to vaporize the cryogen before it is delivered to the use device. The withdrawal line also contains a tank mounted excess flow valve 48 , which protects the downstream piping in case of as line break. Valve 10 in withdrawal line 28 may be taken to represent the throttle of a vehicle with the idea that demand for product is constantly changing. Economizer circuit 34 includes vapor tube 40 , which communicates with head space 36 , and includes economizer regulator 38 , which is set at a predetermined pressure threshold. In this mariner, when the pressure in tank 22 exceeds the set point of regulator 38 , the vapor in head space 36 may be withdrawn through vapor line 40 and to the use device through withdrawal line 28 , which lowers the pressure in tank 22 . However, due to the horizontal nature of LNG vehicle fuel tanks, there is often sufficient hydrostatic pressure to cause liquid 26 to be withdrawn even when regulator 38 is open. Therefore, a biasing relief valve 42 is included in liquid line 24 to cause economizer circuit 34 to be the path of least resistance when regulator 38 is open. A small orifice 44 is located in parallel with relief valve 42 to allow back flow to the tank during transient periods of high to low use.
[0015] Referring now to FIG. 2 , a fuel system with the components previously described plus an additional active pressure: building circuit 55 is shown, Inlet line 51 branches of withdrawal line 28 downstream of vaporizer 32 . Flow inducer 52 causes vaporized gas to flow from inlet line 51 to outlet line 53 which returns the gas to vapor line 40 through cheek valve 54 .
[0016] FIG. 3 shows one possible embodiment of the flow inducing device 52 . Pressure vessel 60 operates at the same pressure as outlet line 53 . Compressor 61 has inlet 63 piped directly to inlet line 51 and has outlet 65 open to the interior of vessel 60 .
[0017] It should be noted that flow inducing device 52 is not limited to a compressor housed inside a pressure vessel. but may take on other forms of actively moving a fluid against a pressure gradient such as a positive displacement pump or other type of motor. Additionally, the process piping of the flow inducing device may be configured in other manners, such as by piping the compressor outlet to the tank and leaving the compressor inlet open to the interior of the vessel.
[0018] FIG. 4 shows one possible embodiment of a controller or control system circuit to activate or deactivate the flow inducing device. A power source, such as a battery 75 . supplies a voltage to device 60 via electrical circuit 76 . The voltage is controlled by several relays and switches (where the terms “relay” and “switch” are used interchangeably herein), which dictate logical events that must occur simultaneously to in order to supply power to device 60 . In order for flow inducing device 60 to operate, the vehicle's ignition switch or key must be turned on to close ignition relay 70 , and the system pressure must be below a predetermined threshold to close pressure relay 71 . Additionally, it is desirable that the engine is operating, in order for device 60 to operate for two reasons: first, to avoid excessive vehicle battery drain and second, to ensure an adequate amount of heat is supplied to vaporizer 32 . A signal indicating that the engine is in operation will close engine operating relay 72 , A manual bypass switch 73 , connected in parallel with engine operating relay 72 , is provided for rare instances when a user may desire to operate the compressor when the engine is not operating (for example, when the tank pressure is too low to even support the engine to start).
[0019] A further description of the logical events for the controller or control system circuit are as follows. The signal to close ignition relay 70 can he simply taken from the vehicles ignition switch 80 ( FIG. 4 ). The signal to close pressure relay 71 requires that the pressure in the system is below a predefined limit. Therefore, a pressure switch or sensor should be included in the system of FIG. 2 to sense a system pressure in one of several locations such as the head space 36 of the tank, as illustrated by sensor 82 in FIGS. 2 and 4 , or somewhere in pressure building circuit 55 , as illustrated by sensor 83 in FIGS. 2 and 4 , and can be used to close relay 71 when the sensed pressure is below the pressure threshold or predetermined minimum pressure. A signal to close the engine operating relay 72 may come from a variety of sources that may serve as an engine operating sensor. The most direct source would be a signal from the on vehicle electrical system, 84 in FIG. 4 , that senses if the engine is operating or not via the engine's electronic control circuitry. Alternatively, an indirect method of detecting the engine operating may be used by including a temperature switch or sensor in inlet line 51 , as illustrated by sensor 86 in FIGS. 2 and 4 , or in the heat exchange space surrounding vaporizer 32 , as illustrated by sensor 88 in FIGS. 2 and 4 , such that relay 72 closes if the temperature is above a predetermined threshold.
[0020] It should be appreciated that the controller may take on other forms not limited to the above description. In any case, the primary goals of the control system are 1) to prevent over pressurization of the cryogenic tank; 2) to prevent excessive discharge of the vehicle's battery when the engine is not operating; and 3) to avoid damage to both vaporizer 32 and flow inducing device 52 due to low temperatures when the engine is not operating. In an alternative embodiment, the controller could be omitted completely and the control system could consist of simply a manually controlled “on” and “off” switch or other manual control switch or device.
[0021] A typical setup and operation of the described system in accordance with an embodiment of the method of the invention is as follows. The minimum allowable inlet pressure to the engine is 70 psig. To allow an adequate buffer in addition to the largest expected pressure drop from the tank to the engine, one might conclude that the normal operating pressure of the tank should be around 100 psig. Therefore, the economizer regulator is set to open at 100 psig, which will work to lower tank pressure to this level when tank pressure exceeds that value. With an economizer set at 100 psig, it would be logical to have the set point on the flow inducing device around 95 psig. Though technically feasible to have flow inducing device active at 100 psig or higher, it is not best practice because there would then be two active competing devices operating at the same time causing unnecessary energy consumption and wear on the components. In this example, suppose the vehicle fuel tank is filled with LNG saturated at 80 psig. When the engine is restarted after fueling, the compressor will immediately turn on and begin to build a false head pressure in the vapor space. In this example, suppose the compressor moves fluid at a rate of 100 L/min. In about one minute, the pressure may rise to 95 psig at which point the compressor will turn off. However, when the vehicle starts driving and the liquid and gas phases slosh together inside the tank, much of that false vapor head pressure will recondense back to liquid phase, and the tank pressure will drop back to a pressure near its starting pressure. The lower pressure will trigger the compressor to turn on again. While the vehicle is in motion and the liquid and gas phases are in thermodynamic equilibrium, the rate of pressure rise will be much slower, and the saturation of the LNG may increase to 95 psig in several minutes. With fuel saturated at the desired level, the compressor may not need to function again until the tank is again fueled with LNG that is not properly saturated to the required level.
[0022] In an alternative embodiment of the delivery system of the invention illustrated in FIG. 5 , a single pressure building circuit 55 may be used in a system consisting of multiple tanks 80 a, 80 b, etc. (while two tanks are shown, an alternative number may be used) configured in parallel. As in the embodiment described previously with respect to FIG. 2 , inlet line 51 branches off of the withdrawal line downstream of vaporizer 32 , and a flow inducer 52 causes vaporized gas to flow from inlet line 51 to outlet line 53 . Outlet line 53 returns the gas to the vapor line of the. economizer circuit and then to the tank head space via check valves 54 a and 54 h for tanks 80 a and 80 b, respectively.
[0023] The controller or control system circuit illustrated in FIG. 4 may also he used to activate or deactivate the flow inducing device 52 of FIG. 5 , Of course, alternative controllers or control system circuits could be used. Returning to the embodiment of FIGS. 4 and 5 , the signal to close pressure relay 71 requires that the pressure in the system is below a predefined limit. Therefore, a pressure switch or sensor should be included in the system of FIG. 5 to sense a system pressure in several locations, such as the bead spaces of the tanks 80 a and 80 b or somewhere in pressure building circuit 55 , and can be used to close relay 71 of FIG. 4 when the sensed pressure is below the pressure threshold or predetermined minimum pressure. If the pressure in one of the tanks is below the pressure threshold or predetermined minimum pressure (for example, tank 80 a ) and the other pressure of the other tank is not (for example, tank 80 b ), the chock valve corresponding to the tank that is not below the pressure threshold or minimum pressure (check valve 54 b in the present example) will prevent gas from the pressure building circuit 55 from entering that tank (tank 80 b in the present example).
[0024] While the preferred embodiments of the invention have been shown and described, it will he apparent to those skilled in the art that changes and modifications may be made therein without departing from the spirit of the invention, the scope of which is defined by the appended claims. | A cryogenic fluid delivery system includes a tank adapted to contain a supply of cryogenic liquid, with the tank including a head space adapted to contain a vapor above the cryogenic liquid stored in the tank. A liquid withdrawal line is adapted to communicate with cryogenic liquid stored in the tank. A vaporizer has an inlet that is in communication with the liquid withdrawal line and an outlet that is in communication with a vapor delivery line. A pressure building circuit is in communication with the vapor delivery line and the head space of the tank. The pressure building circuit includes a flow inducing device and a control system for activating the flow inducing device when a pressure within the head space of the tank drops below a predetermined minimum pressure and/or when other conditions exist. | 5 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a ball grid array (BGA) type semiconductor device and its manufacturing method. Particularly, it relates to the improvement of a repairing method of defective solder generated when the BGA type semiconductor device is mounted on a motherboard.
[0003] 2. Description of the Related Art
[0004] Since BGA type semiconductor devices (packages) can have a larger number of external terminal pins as compared with quad flat packages (QFPs) and small outline packages (SOPs), such BGA type packages have recently been developed.
[0005] In a prior art method for manufacturing a BGA type semiconductor device, a semiconductor chip is mounted on a first surface of an interposer substrate. On the other hand, solder balls are provided on a second surface of the interposer substrate. As a result, the semiconductor chip is electrically connected via through holes having a relatively small diameter provided in the interposer substrate to the solder balls. Next, the BGA semiconductor device is mounted on a motherboard by soldering the solder balls thereto. This will be explained later in detail.
[0006] In the above-described method, an open state or a short-circuit state may be generated due to the defective soldering process. In order to repair the open state or the short-circuit state, the interposer substrate is separated and detached from the motherboard by a heating process using hot air blown via through holes provided within the motherboard 4 (see JP-A-9-181404) or by a special local heating process using hot air blown via nozzles provided at the periphery of the BGA type semiconductor device (see JP-A-11-26929). Then, the surface of the motherboard is cleaned, and solder paste is again adhered thereto. Finally, a new BGA type semiconductor device is mounted on the motherboard. Note that BGA type semiconductor devices including such defective solder balls are usually discarded. Thus, the manufacturing cost is increased.
SUMMARY OF THE INVENTION
[0007] It is an object of the present invention to decrease the manufacturing cost of BGA type semiconductor devices.
[0008] According to the present invention, in a BGA type semiconductor device including an interposer substrate having first and second surfaces, a semiconductor chip mounted on the first surface of the interposer substrate, and solder balls formed on the second surface of the interposer substrate, a plurality of through holes are formed within the interposer substrate, and each of the solder balls clogs one of the through holes of the interposer substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The present invention will be more clearly understood from the description set forth below, as compared with the prior art, with reference to the accompanying drawings, wherein:
[0010] [0010]FIGS. 1A and 1B are cross-sectional views illustrating a prior art method for manufacturing a BGA type semiconductor device;
[0011] [0011]FIGS. 2A and 2B are cross-sectional views for explaining defective soldering states of the BGA type semiconductor device of FIG. 1B;
[0012] [0012]FIGS. 3A and 3B are cross-sectional views illustrating a first embodiment of the method for manufacturing a BGA type semiconductor device according to the present invention;
[0013] [0013]FIGS. 4A and 4B are cross-sectional views for explaining defective soldering states of the BGA type semiconductor device of FIG. 3B; and
[0014] [0014]FIGS. 5A and 5B are cross-sectional views illustrating a second embodiment of the method for manufacturing a BGA type semiconductor device according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] Before the description of the preferred embodiments, a prior art method for manufacturing a BGA type semiconductor device will be explained with reference to FIGS. 1A and 1B.
[0016] First, referring to FIG. 1A, a semiconductor chip 1 is mounted on a first surface of an interposer substrate 2 . In this case, the semiconductor chip 1 can be of a flip-chip type. On the other hand, solder balls 3 a and 3 b are provided on a second surface of the interposer substrate 2 . The semiconductor chip 1 is electrically connected via through holes 2 a and 2 b having a relatively small diameter such as 0.3 mm provided in the interposer substrate 2 to the solder balls 3 a and 3 b , respectively. Note that metal layers (not shown) are formed within the through holes 2 a and 2 b.
[0017] Next, referring to FIG. 1B, the BGA semiconductor device of FIG. 1A is mounted on a motherboard 4 by soldering the solder balls 3 a and 3 b thereto.
[0018] In the method as illustrated in FIGS. 1A and 1B, an open state or a short-circuit state may be generated due to the defective soldering process. For example, as illustrated in FIG. 2A, the solder ball 3 a is disconnected from the motherboard 4 , which shows an open state. On the other hand, as illustrated in FIG. 2B, the solder ball 3 a is electrically connected to the solder ball 3 b , which shows a short-circuit state.
[0019] In order to repair the open state as illustrated in FIG. 2A or the short-circuit state as illustrated in FIG. 2B, in the prior art, the interposer substrate 2 is separated and detached from the motherboard 4 by a heating process using hot air blown via through holes provided within the motherboard 4 (see JP-A-9-181404) or by a special local heating process using hot air blown via nozzles provided at the periphery of the BGA type semiconductor device (see JP-A-11-26929). Then, the surface of the motherboard 4 is cleaned, and solder paste is again adhered thereto. Finally, a new BGA type semiconductor device is mounted on the motherboard 4 . This would increase the manufacturing cost.
[0020] Note that BGA type semiconductor devices including such defective solder balls are usually discarded.
[0021] A first embodiment of the method for manufacturing a BGA type semiconductor device according to the present invention will be explained next with reference to FIGS. 3A and 3B.
[0022] First, referring to FIG. 3A, a semiconductor chip 1 is mounted on a first surface of an interposer substrate 2 . In this case, the semiconductor chip 1 can be of a flip-chip type. On the other hand, solder balls 3 a and 3 b are provided on a second surface of the interposer substrate 2 . The semiconductor chip 1 is electrically connected via through holes 2 a ′ and 2 b ′ having a relatively large diameter such as 0.5 mm provided in the interposer substrate 2 to the solder balls 3 a and 3 b , respectively. In this case, the solder balls 3 a and 3 b are provided so as to clog the through holes 2 a 40 and 2 b ′, respectively. Also, metal layers (not shown) are formed within the through holes 2 a ′ and 2 b′.
[0023] Next, referring to FIG. 4B, the BGA semiconductor device of FIG. 4A is mounted on a motherboard 4 by soldering the solder balls 3 a and 3 b thereto.
[0024] Even in the method as illustrated in FIGS. 3A and 3B, an open state or a short-circuit state may be generated due to the defective soldering process. For example, as illustrated in FIG. 4A, the solder ball 3 a is disconnected from the motherboard 4 , which shows an open state. On the other hand, as illustrated in FIG. 4B, the solder ball 3 a is electrically connected to the solder ball 3 b , which shows a short-circuit state.
[0025] In order to repair the open state solder ball 3 a in FIG. 4A, melted solder is added by using a special tool via the through hole 2 a ′ onto the solder ball 3 a as indicated by an arrow, so that the solder ball 3 a can be in touch with the motherboard 4 . Thus, the solder ball 3 a can be repaired without separating and detaching the interposer substrate 2 from the motherboard 4 , which would decrease the manufacturing cost.
[0026] In order to repair the short-circuited solder balls 3 a and 3 b in FIG. 4B, the solder balls 3 a and 3 b are sucked by using a special tool as indicated by arrows. Then, melted solder is injected by using a special tool into the through holes 2 a ′ and 2 b ′, so that new solder balls can be in touch with the motherboard 4 . Thus, the short-circuited solder balls 3 a and 3 b can be repaired without separating and detaching the interposer substrate 2 from the motherboard 4 , which would decrease the manufacturing cost.
[0027] A second embodiment of the method for manufacturing a BGA type semiconductor device according to the present invention will be explained next with reference to FIGS. 5A and 5B.
[0028] First, referring to FIG. 5A, resin layers 5 a and 5 b are formed in advance within through holes 2 a ′ and 2 b ′ of an interposer substrate 2 . Then, a semiconductor chip 1 is mounted on a first surface of the interposer substrate 2 . In this case, the semiconductor chip 1 can be of a flip-chip type. On the other hand, solder balls 3 a and 3 b are provided on a second surface of the interposer substrate 2 . The semiconductor chip 1 is electrically connected via through holes 2 a ′ and 2 b ′ having a relatively large diameter such as 0.5 mm provided in the interposer substrate 2 to the solder balls 3 a and 3 b , respectively. In this case, the solder balls 3 a and 3 b are provided so as to clog the through holes 2 a ′ and 2 b ′, respectively. Also, metal layers (not shown) are formed within the through holes 2 a ′ and 2 b′.
[0029] Next, referring to FIG. 5B, the BGA semiconductor device of FIG. 4A is mounted on a motherboard 4 by soldering the solder balls 3 a and 3 b thereto.
[0030] The resin layers 5 a and 5 b serve as means for supporting the solder balls 3 a and 3 b . Therefore, if the BGA semiconductor device of FIG. 5A is relatively heavy, the solder balls 3 a and 3 b cannot penetrate the through holes 2 a ′ and 2 b ′, respectively, due to the presence of the resin layers 5 a and 5 b.
[0031] Even in the method as illustrated in FIGS. 5A and 5B, an open state or a short-circuit state may be generated due to the defective soldering process in the same way as in the first embodiment.
[0032] In order to repair the solder ball 3 a and/or 3 b in FIG. 5B, the resin film 5 a and/or 5 b is first removed by a mechanical or chemical process. Then, the solder ball 3 a and/or 3 b can be repaired in the same way as in the first embodiment. Thus, the solder ball 3 a and/or 3 b can be repaired without separating and detaching the interposer substrate 2 from the motherboard 4 , which would decrease the manufacturing cost.
[0033] As explained hereinabove, according to the present invention, since defective solder balls can be repaired without separating and detaching an interposer substrate from a motherboard, the manufacturing cost can be decreased. Note that BGA semiconductor devices including such defective solder balls can be reused. | In a ball grid array type semiconductor device including an interposer substrate having first and second surfaces, a semiconductor chip mounted on the first surface of the interposer substrate, and solder balls formed on the second surface of the interposer substrate, a plurality of through holes are formed within the interposer substrate, and each of the solder balls clogs one of the through holes of the interposer substrate. | 8 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit under 35 USC §119(e) of a United States (US) provisional patent application filed on Apr. 26, 2002 under Ser. No. 60/375,619 whose contents are incorporated by reference.
TECHNICAL FIELD
This invention relates to the general subject of production of oil and gas and, in particular, to marine risers used in the production of oil and gas from the seabed.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable.
REFERENCE TO A “MICROFICHE APPENDIX”
Not applicable.
BACKGROUND OF THE INVENTION
Marine riser technology and its development have been driven by two basic needs in the oil industry.
The first need has been to resolve the challenges that are related to using drilling risers during exploratory drilling. These risers bridge between the seabed and the surface when doing exploration drilling from a floating vessel, which is normally either a semi-submersible drilling rig, or a drill ship. These riser needs can be characterized as large diameter and relatively low pressure. They are designed for rapid disconnect from the seabed equipment, efficient running and retrieval via the drilling vessel, and relatively short design life. Basic floating drilling methods were established in the 1960's 1 (superscripts refer to “List of References” appearing before the Claims at the end of this specification) and these methods continue to be improved upon today 2 .
The second riser need occurs when exploration drilling is successful, leading to a field development. These field development risers bridge between the life-of-field development seabed and surface Host Facility. These risers have small diameters and large diameters, operate at relatively high pressures, and are designed in accordance with field development expectations for near-continuous hydrocarbon depletion that may require 20 years and more of uninterrupted service. These risers may include export and import riser systems that are related to the hydrocarbon production and sales. Also, if well drilling and completion is to be performed from the Host Facility, these riser needs have also to be addressed 3 .
The pace for deepwater developments in the Gulf of Mexico has been dramatic since the mid-1990's. A brief summary is presented in Appendix IV. The Industry has gone through a series of stages of riser technology development, resulting in the present preferred Steel Catenary Riser (SCR)/Flowline (FL) riser solutions for deepwater. SCR's have evolved in a natural way to replace the large, complex and costly top tensioning equipment that are required when vertical riser systems are used. Vertical risers with top tensioning are effective to water depths of about 4000 feet. However, top tensioning equipment, because of its size, weight, and tight clearances, is costly and difficult to manage. This geometric relationship becomes increasingly challenging when the Host Facility must support this equipment for riser strokes of more than 7–12 feet. For one project in the Gulf of Mexico in 6000 feet of water, riser top motions can approach about 20 feet. These motions represent major design challenge, even for the SCR/FL risers. The challenge is magnified due to the large number of risers that must bridge between the seabed and the Host Facility.
This stroke length is necessary to accommodate the change in riser system length as the Host Facility moves from its neutral position. Without this riser stroke, the riser would be subjected to either over-stressing or large stress level cycles. Riser failure can be manifested by either overstressing it, or by subjecting it to excessive stress cycling. The stress cycling can lead to riser failure due to accumulated fatigue damage, even though the allowable stress is not exceeded for the riser system.
The riser stroke length challenge is graphically represented in FIG. E-2 of a U.S. provisional patent application filed on Apr. 26, 2002 under Ser. No. 60/375,619. When a riser is attached to a fixed point on the seabed and directly to the Host Facility, the riser top must move along with the Host Facility. Considering the life of field possibilities, the range of motions that may occur is extensive. The solution to this changing riser length (stroke requirement) should be robust, as failure to do so is can lead to riser failure. Riser failure can be caused either by the immediate effect of over-stressing, or by diminished fatigue life due to excessive stress cycling. Riser failure due to collapse can also occur, but this tends to be a direct consequence of over-stressing it. In the case of Host Facilities that have very large motions, such as the FPSO systems that have been used outside the Gulf of Mexico, the riser stroke requirement can be met by using flexible pipe 16 .
A flexible pipe solution (See FIG. E-3(a) of the U.S. provisional patent application filed on Apr. 26, 2002 under Ser. No. 60/375,619), has been used successfully many times. However, for very deep water, this method can be costly. Also, flexible pipe technology for risers (i.e., ones that require a design combination of deepwater, high pressure, high temperature, or large size) remains under on-going development before flexible pipe will be ready for the long field life riser applications. Flexible pipe risers can provide good closing solutions when used in conjunction with a free-standing rigid riser (See FIG. E-3(b) of the U.S. provisional patent application filed on Apr. 26, 2002 under Ser. No. 60/375,619). This arrangement is sometimes referred to as a “hybrid riser” because it combines elements of both buoyancy for top tensioning of the steel risers and flexible pipe to complete the bridging from the top of the rigid risers to the Host Facility. This arrangement is commonly used for Spar well system jumpers that bridge between the well tree and the host manifold. The flexible pipe elements are comprised of a wall body that is made up of various combinations of metal and elastomers. The flexible pipe design is tailored to meet each specific application need. Although the resulting flexibility can help resolve the strokelength challenges that exist with rigid risers and they provide an efficient closing duty, their use for a life-of-field application for the entire riser system remains uncertain. Also, specialized installation methods are often used to ensure that the integrity of flexible pipe is maintained.
The fundamental need for a top-tensioning assembly is represented in FIG. E-4A of the U.S. provisional patent application filed on Apr. 26, 2002 under Ser. No. 60/375,619). In that example, no top-tensioning assembly with stroke length change is provided for the riser. Thus, it bridges directly between the seabed connection point and a point on the host facility. This is only shown as a hypothetical configuration. It assumes that the Host Facility could be designed such a way that the combination of hull and mooring would limit the hull motions so that this would be feasible. Also, it assumes that no over pull is applied to the riser at the neutral position. In an actual design, some over pull is necessary to ensure riser integrity for the range of environmental loads to which it will be subjected. However, as can be seen in this drawing, as the Host Facility moves laterally from its neutral position, the riser top-tensile stress begins to increase rapidly. In this example, an allowable material stress value of about 60,000 psi was assumed. Modern steels can be manufactured to provide material properties like this, including the direct requirement for suitable welding methods. Work to provide suitable commercial grade steels of higher stress values is continuing. But if it were possible to keep the Host Facility offset to within a very small percent of water depth, this type of rigid riser could be feasible today if cost realities related to the hull and mooring were not a consideration.
Given the recent pace of these developments, it is easy to understand why a deepwater field development would be based on the most proven riser systems that are available to the system designers. However, when subsea wells and equipment are located directly under the Host Facility, managing the seabed equipment, wells flowlines, and risers is costly and complex. The SCR/Flowline system requires that the SCR be routed in a straight line and away from the Host Facility. The flowline is routed around and back under the Host Facility, where it can then be connected to the subsea manifold using a jumper. Also, a flowline jumper arrangement is required to allow efficient transition between the SCR and the flowline. The drilling riser that is located on the Host Facility can be equipped with a conventional riser top-tensioning system. This is possible because it can be disconnected when Host Facility motions exceed a pre-determined limit. Since the production export and import risers cannot be disconnected this way, the use of a top tensioning assembly at the surface for these risers can only be obtained at the expense of space, weight, and clearance requirements on the topsides. The complexity and cost of doing this is high for deepwater applications. This is the fundamental reason why the SCR/Flowline method has been used. It represents a better solution than can be achieved by using a vertical riser with a top tensioning assembly. Top-tensioned risers continue to meet field development needs, and it is expected that they will continue to do so for many situations. Even so, the need for new approaches continues. Current riser design practices 15 recognize this need, and theses practices provide guidance on the approaches that can be used to qualify new riser designs.
In those cases that require vertical access into the riser system, a top tensioning assembly may continue to be a preferred solution, as this may be the only practical means for providing vertical riser access for well drilling and completion purposes. However, some types of risers do not require vertical access. These riser systems include the export and import risers that are used to move products away from and onto the Host Facility. The SCR/FL solution can also be used to meet these duties, especially for the larger riser sizes.
These problems have existed for some time. Considerable effort has been made, and significant amounts of money have been expended to resolve this problem. In spite of this, the problem still exists. Actually, the problem has become aggravated with the passage of time because the water depth requirements continue to rely on costly solutions, or solutions that are approaching their limits of practical application.
SUMMARY OF THE INVENTION
In accordance with the present invention, a bottom tensioned riser (BTR) assembly is disclosed comprising: a generally extendable coil section having an upper end adapted to be in flow communication with a generally vertical marine riser carried by a facility floating on the surface of a body of water, and having a lower end adapted to be in flow communication with a fluid source on the seafloor; and tensioning means, mechanically connecting the upper end of the marine riser with the lower end of the marine riser, for biasing said ends towards each other. The tensioning means comprises: a cylinder having one end open to sea pressure, having an opposite end sealed from sea pressure, and connected to the lower end of the vertical marine riser; a piston within the cylinder slidably and sealingly disposed for movement within the cylinder; and a piston rod sealingly and slidably moving through the opposite end of the cylinder having one end connected to the piston and having an opposite end connected to the upper end of the vertical marine riser.
The BTR can be designed to meet a wide range of Host Facility motions throughout the field development life, and it eliminates the need for disconnecting the vertical export/import riser. This is made possible by virtue of a coil section, which is located in the lower portion of the riser system. One unique aspect of the invention is that it solves a riser system application problem that has normally been approached from the surface/Host Facility (i.e., from the top down). The BTR concept, which approaches the top tension problem from the bottom up, provides a solution that has both technical and cost benefits.
The technical benefits include its use as a vertical riser system. The vertical riser system projection onto the seabed is low when compared to other methods. By virtue of this, it simplifies the seabed architecture. Simplicity in deepwater operations is directly related to the magnitude of risk of unplanned occurrences happening. The vertical riser design can be performed using analysis techniques and assumptions that are proven. The time required to do the analysis of a vertical riser is roughly one-half that of a SCR. The reason that the SCR requires so much more time is that it is a relatively new type of riser itself. Specialized and proprietary analysis methods are required for demonstrating riser fatigue life at the SCR touchdown point. The SCR touchdown point and lift-off modeling remains an area that is under research work to better resolve uncertainties about the models and their required assumptions. A SCR also requires proprietary modeling that is related to vortex-induced-vibrations (VIV). Since the riser shape is not vertical through the water column, VIV modeling cannot be performed in the traditional ways. Research work in this area of modeling is also continuing. The BTR concept can be designed to impose a relatively low top tensile load on the Host Facility. This tensile load change can be designed to be relatively small as the Host Facility goes through its full range of motions. This feature reduces the risks that are associated with predicting both the riser system maximum tensile stress and the fatigue design life that results from stress cycles. The BTR design can be configured to be forgiving without incurring excessive costs. If Host Facility motions are not identical to analytical predictions or model basin simulations, the BTR can be configured to provide a conservative design margin to allow for the differences from these predictions.
The BTR coil section can be designed so that it contains a minimum number of active components that require maintenance or repair. If it is necessary to replace any of these elements during field life, the coil section design lends itself to either replacement of individual components or the entire coil section, if this is necessary.
Cost efficiency of the BTR over present methods is summarized in FIG. D-3 of the U.S. provisional patent application filed on Apr. 26, 2002 under Serial No. 60/375,619. Riser sizes depend on specific application needs, but 8-inch through 12-inch sizes are common. Both smaller and larger sizes may be necessary in any particular application, but the trends that are identified in this Figure are representative. In comparison to the SCR/Flowline method, the BTR cost benefit is estimated to be about $2.9 million; $3.2 million; $3.5 million for each 8-inch, 10-inch, and 12-inch riser, respectively. This comparison assumes that a completely independent riser installation is used to install the BTR systems. When the Host Facility is equipped with a drilling rig, it is feasible to consider using the drilling rig to do the BTR running activities. If this BTR alternative is used, these same benefits are estimated to increase to $3.9 million, $4.3 million, and $4.8 million. Overall, the first set of benefits represent about a 33 percent cost reduction.
Most deepwater field developments will require site-specific numbers and sizes of risers. A representative example is provided in FIG. D-4 of the U.S. provisional patent application filed on Apr. 26, 2002 under Ser. No. 60/375,619). In this example, the BTR benefit represents a cost reduction of about $54 million, and the alternative BTR installation method represents about $75 million. These are cost benefits of about 32 percent and 44 percent, respectively.
Since the coil section diameter is relatively large, it is located a substantial vertical distance away from the Host Facility. By placing the coil section near the bottom of the riser, the required space is readily available. This location has the inherent and important advantage that it then only needs to support its own self-weight during installation and operation. If it were to be placed near the top of the riser, it would not only have to carry its own weight, but that of the riser suspended below it, both during installation and throughout its operating life.
In the case of export and import risers, the BTR invention may provide cost benefit over alternative riser solutions. And when compared to present methods, the technical benefits may also be significant, especially for deepwater configurations that use seabed equipment that is located under the Host Facility.
The BTR system is one way to simplify the deepwater challenge. Riser top tensile stresses for this new system are shown in FIG. E-4B of the U.S. provisional patent application filed on Apr. 26, 2002 under Ser. No. 60/375,619). That figure shows that the new rigid riser system can provide a relatively low top tensile stress level across the range of possible Host Facility motions.
Numerous other advantages and features of the present invention will become readily apparent from the following detailed description of the invention, the embodiments described therein, from the claims, and from the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the overall environment of the invention;
FIG. 2 illustrates a side elevation view of a basic embodiment of the invention;
FIG. 3 depicts top, side elevation, and front views of the Coil Section;
FIG. 4 shows an enlarged elevation view of the invention with the Coil Section removed;
FIG. 5 depicts a top view of the apparatus shown in FIG. 4 ;
FIG. 6 shows the locking mechanism in its locked position;
FIG. 7 shows the locking mechanism in its un-locked position;
FIG. 8 depicts three optional arrangements of the BTR assembly;
FIG. 9 shows the basic global geometry of the BTR; and
FIG. 10 depicts minimum coil diameter consistent with 5Do pipe bends;
LIST OF TABLES
Table 1 BTR Advantages and Disadvantages
DETAILED DESCRIPTION
While this invention is susceptible of embodiment in many different forms, there is shown in the drawings, and will herein be described in detail, one specific embodiment of the invention. It should be understood, however, that the present disclosure is to be considered an exemplification of the principles of the invention and is not intended to limit the invention to any specific embodiment so described.
Turning to FIG. 1 , the invention, and the overall environment of one embodiment of the invention is illustrated. At the upper half of the drawing is shown a Host Facility in the form of a semi-submersible platform and a floating production system 3 Production Drilling Quarters (PDQ). The PDQ comprises a drilling rig 4 , topsides 5 , crew quarters 6 , cranes 7 , and an emergency flare 8 . The superstructure of the PDQ is supported by columns 10 which are connected to pontoons 11 which are submerged below the surface 1 of the water. The PDQ is positioned by mooring lines 12 which extend to the seabed 2 . A drilling riser 13 is shown supported by the drilling rig 4 . Also shown are a production riser porch 14 and an export pipeline porch 15 . An export pipeline 16 sends oil to another facility.
Looking at the bottom of FIG. 1 , a clustered well manifold system 17 is shown on the seafloor 2 . The drilling riser 13 extends to a lower marine riser package 18 and a blowout preventer 19 to a subsea wellhead 20 . Flowline jumpers 23 join subsea Christmas Trees 21 to a subsea manifold 22 . Manifold jumpers 24 join the subsea manifold 22 to the Bottom Tension Riser (BTR) system 25 that is the subject of the present invention.
Turning to FIG. 2 and FIG. 3 , the BTR system 25 is located above the riser base 26 and below a generally long vertical section of main production riser 32 . The BTR comprises a Coil Section 27 , a lower connector 28 , flexing elements 29 , a tensioning assembly 30 , and an upper connector 31 . The riser base 26 has a jumper vertical connector hub 33 and a horizontal connector hub 34
FIG. 4 and FIG. 5 show the BTR system 25 with the Coil Section removed. There are four tensioning units 40 . A tensioning rod 39 extends from each unit and is mechanically connected to the upper structure and connector 38 . An auxiliary tensioning pressure unit 41 and a sea chest 42 are joined to the main body of the tensioning unit 40 . The main body of the tensioning unit is connected to the lower structure and connector 43 .
The locking mechanism 44 is shown in FIG. 6 and FIG. 7 . FIG. 6 shows the mechanism in the “locked” position. FIG. 7 shows the mechanism in the “open” position. The locking mechanism mechanically connects the main body of a tensioning unit 40 with the upper connector 31 . The mechanism comprises a fixed pawl 44 a is connected to the upper connector 31 . Another pawl 44 b is pivotally connected to the tensioning unit 40 . The free end of that pawl 44 b is moved towards and away from the free end of the fixed pawl 44 a by means of a locking screw 46 that is preferably configured to be operated by a Remotely Operated Vehicle (ROV). Thus, when the screw 46 is advanced toward the pivoted pawl 44 b , the two pawls separate. A clearance tolerance 49 allows the upper connector 31 to move away from the main body of the tensioning unit 40 .
The BTR system 25 is unique in at least four important ways:
First, it provides the means for providing top tension at the Host Facility in a way that tensile stresses remain relatively low throughout the range of Host Facility offsets. This is important because it ensures that riser integrity can be maintained as the Host Facility moves about.
Second, the stroke length requirement is provided via the Coil Section, which is contained within the lower section of the riser. Thus, the BTR system remains essentially transparent to the design of the hull and topsides. This is important because it simplifies hull and topsides designs.
Third, since this is a vertical riser system, it projects a relatively small footprint onto the seabed. This is important, particularly for those field developments that use of subsea wells and equipment that are located under the Host Facility. In these situations, the BTR approaches being an “enabling technology”. This is because there is only limited space at the seabed to accommodate the system and seabed equipment architecture needs.
Fourth, the BTR concept can be configured so that it is a “forgiving” arrangement, with minor cost increase to do so. Forgiving in this context refers to those situations in which the Host Facility could be displaced beyond its expected limits. The importance of the BTR system is that the Coil Section 27 can be provided with a conservative stroke length to account for this possibility. The reason that this is feasible is that unlike the topsides, where interface limits measure in inches between the riser and topsides equipment, ample headroom exists at the lower section of the riser. This feature allows many optimizing opportunities for the BTR system.
Moving on to the BTR rod and piston elements there are at least two basic approaches that can be used for this part of the system.
The first approach is to use a “closed” arrangement for the pressurized gas that is used in the cylinder and rod assembly. This method is represented in FIG. 8A . The gas is installed at a pre-determined pressure, and the pressure in the cylinder increases or decreases as the rod and piston move up or down, respectively. This approach has the advantage that it is cost efficient, but it may require occasional intervention to replenish the gas. In the event of component failure, removal and repair or replacement of the unit may be necessary. However, this design can provide an efficient solution. It is the basis that is used for developing the riser top tensile stress computations that are shown in FIG. E-4(b) of the U.S. Provisional Patent Application Ser. No. 60/375,619 filed on Apr. 26, 2002 This approach results in tensile stress increase, primarily as the Host Facility approaches maximum offset limits. Even so, the related maximum tensile stress remains well within acceptable limits. Most of the time, Host Facility offsets will be much less than the extreme offsets, and the tensile stress change is quite small.
The second approach is to use an “open” system for the pressurized gas that is used in the cylinder and rod assembly This method is represented in FIG. 8B . This approach has the advantage that a constant level of gas pressure can be applied via the Host Facility, resulting in the capability to maintain a near constant level of pressure on the cylinder and rod piston. This allows maintaining a more constant top tensile stress at the top of the riser throughout the range of Host Facility movements. However, this additional capability comes at considerable additional cost and complexity, with near certainty that the frequency of component failure, removal or replacement of the unit is expected to be little different than for the closed system approach. Due to the added complexity of this system, it could even require more frequent intervention than for the closed system approach. In any case, these are the reasons why the closed system approach is assumed for this BTR concept assessment.
FIG. 8C shows another variation of the “open system” approach wherein an auxiliary cylinder 41 is co-axial with the main cylinder 40 . Details of the comparison of different cylinder, rod, piston, and auxiliary cylinder configurations are provided in the Appendix II. The “piggy-back” auxiliary cylinder method is beloved to provide the most efficient solution for the cylinder volumes required for this type of application.
Dynamics
This invention has immediate application to situations where top tensioned risers have been used to transfer products between a floating Host Facility and the seabed for deepwater oil and gas field developments. Referring to FIG. 2 , there are two basic elements.
The first element is placement of the top tensioning equipment in the lower portion of the riser rather than at the top of the riser. By placing this equipment at the bottom of the riser system, the tensioning assembly is subjected to lower loads than when the tensioning assembly is placed at the top of the riser. This load reduction is roughly equal to the riser weight in water.
The second element is the use of a Coil Section 27 that lengthens and shortens to accommodate the Host Facility movements. In addition to this, it provides the required riser top tension to maintain riser integrity. By virtue of this invention, the need for large, complex, and costly top tensioning equipment at the interface with the Host Facility is eliminated. Since the Coil Section is placed at the bottom of the riser, it can accommodate most any Host Facility motions that fall within the practicalities of building, transporting and installing the Coil Section.
The BTR system global geometry is summarized in FIG. 9 . There are three important aspects of the riser system:
1. installation, 2. performance at the Host Facility neutral position, and 3. performance at Host Facility offset positions, including possible extreme events.
Turning to system installation, this is represented by FIG. 9A . The overall riser length is l to for a given water depth. The main riser section, which will make up most of the riser system, will have a riser section length, l r . As can be seen, it is the length of the riser system (excluding the height of the riser base and Coil Section above the seabed). This main part of the riser is commonly made from steel, but other materials, such as titanium, have been used. The weight of this riser during installation will include its weight in water during installation, and that of the Coil Section weight, W c . After installation, the weight of product carried within the riser will be also need to be included. These riser weights are represented by W r .
Before lowering the main riser section to the seafloor, the Coil Section of length l c and self-weight in water W c is attached to the riser. Since the Coil Section 27 is attached to the lower section of the main riser, the Coil Section carries only its own weight and that of the riser bottom connector and any special riser or subsea components that may be necessary for a specific application. This results in the riser system that is short of its final installed length by the value l o . The riser top tension at this point is T r . Once the riser system is landed and locked onto the riser base, the riser system is pre-tensioned to provide a pre-determined riser top tension, T ro . This is performed in conjunction with docking the riser top into the riser top connector that is provided on the Host Facility. At this point, the Coil Section is extended by the length l eo , resulting in the Coil Section tension load T co that causes the riser system top to increase to T ro . The connected and pre-tensioned riser system is represented by FIG. 9B . These riser system installation activities described herein are typical of those that are used when installing many types of deepwater equipment.
Performance at the Host Facility neutral position will now be addressed. At the Host Facility neutral, or no offset position, environmental responses and operational load changes will cause the need for riser length changes to occur. Also at this position, the riser top tension should be sufficient to ensure appropriate riser system behavior through the long water column. Maintaining the riser top tension to an amount that is somewhat more than the weight of the riser system does this. The pre-tensioning as described above causes the Coil Section length to increase from its original length l C by an amount l eo . This results in the Coil Section length l CO at the neutral position. This pre-tensioning load is transmitted directly through the main riser body and into the riser top connector, resulting in the total riser top tension, T ro . Thus, as Host Facility motions or operating loads change, the Coil Section length l eo also changes accordingly.
Performance at the Host Facility offset positions will now be addressed. The third set of conditions that the riser system should satisfy is represented in FIG. 9C . These conditions occur when the Host Facility moves laterally from it neutral position. During a possible extreme event, this offset can approach in excess of five percent of the water depth. From a riser system configuration standpoint, all motions are important. But of these motions, the most important is the Host Facility extreme offset conditions. In an area like the Gulf of Mexico, hurricanes normally define the extreme events, which in turn determine the Host Facility maximum offset. However, in some situations, the Host Facility may be offset even more than this for system operating purposes. If this is so, this need should also be accounted for in the riser system configuration. During hurricane events, Host Facilities are commonly de-manned. During these periods, the riser system should continue to perform without any requirement for man-machine interaction. The offset x, as shown in FIG. 9C , is used to represent all Host Facility and the connected riser system lateral displacements. Since a moored, floating body experiences six degrees of motion, and not just the single degree of freedom motion (x offset) that is represented in this drawing, additional allowance for the other five degrees of motion is necessary in actual practice. However, since x is the most significant single item, a first approximation of the change in riser system length can be defined using equations (1), (2) and (3):
tan −1 ( x/l to )=θ (1)
cos(θ)= l to /l tx (2)
l tx =l to /cos(θ) (3)
l ex =l tx −( l r +l c ) (4)
The main riser body length l r is essentially unchanged as the Host Facility offsets from its neutral position. The Coil Section length extends beyond its neutral position length l eo to satisfy the extreme event Coil Section extension length l ex , as shown in equation (4). This results in a total Coil Section extended length of l cx and riser system length of l tx for the extreme offset conditions. These same relationships can be used to characterize the riser system throughout the range of Host Facility offset positions between the neutral and maximum positions. The Coil Section is a key part of the BTR system. It is now described in more detail.
The export and import riser duty of the BTR system should satisfy specific Industry Practice design features. The overall Coil Section assembly is shown in FIG. 2 . It consists of the upper and lower connectors 31 and 28 , the Coil Section 27 , and the tensioning unit 40 . The connectors are commercially available components today, so they are not be described in detail. However, the way in which the connectors are configured to meet the specific requirements of the BTR Coil Section is unique, and their use in this way is included in this application. The main Coil Section is described first, followed by the tensioning unit and the complete assembly.
The Coil Assembly is shown in FIG. 3 . As shown in the plan and elevation views, it consists of six components.
The first two components are the upper connector 31 and lower connector 28 . Each connector is required to provide the structural strength that is needed to transmit loads and provide pressure isolation for the riser production as it is moved from the main riser body into the riser base. These connectors are commercially available today, so no further description is necessary.
The next component is the Pipe Section 35 for the Tensioning Assembly 30 . The Pipe Section 35 is an engineered segment of pipe that provides the attachment to the bottom of the upper connector 31 and the top of the Upper Coil Transition Section 36 (described later). The Pipe Section 35 serves two purposes. The first purpose is to provide a length of pipe that reduces the number of individual coils to the minimum number of coils that are needed in the Coil Section 27 . For most situations, excluding Pipe Section 35 would result in the need for using more coils than is required to meet the Coil Section maximum stroke length. The Pipe Section 35 provides design efficiency for each application. The second purpose for Pipe Section 35 is to provide the strength that is needed to expand the coils while providing pressure isolation for the riser products.
The next component of the Coil Section 27 is the Upper Coil Transition Section 36 . It is connected to the bottom of the Pipe Section 35 and the uppermost coil. The Upper Coil Transition Section 36 has two purposes. The first is to provide the strength that is required to expand the uppermost of the coils while providing pressure isolation for the riser products. The second purpose is to provide this transition in accordance with Industry Practices for export and import pipelines. Basically, this means that the Upper Coil Transition Section 36 will have a minimum pipe bend limit throughout its own shape and as it makes the tangential transition into the connection with the uppermost of the coils. FIG. 10 shows one way in which the Industry Practice for minimum bend radius criteria determines the geometry of both the Upper Coil Transition Section 36 and the main coils.
The engineered coils are the next components of the Coil Assembly. These coils have two purposes: The first purpose is to provide the flexibility that will satisfy the stroke length changes that will be required by the riser system as the Host Facility moves. The second purpose is to provide pressure isolation for the riser products between the Upper Coil Transition Section 36 and the Lower Coil Transition Section 37 .
The last component of the Coil Assembly is the Lower Coil Transition Section 27 . It bridges between the coils and directly to the Lower Connector 28 . The purposes for the Lower Transition Section 5 and the Lower Connector 28 are the same as those described for the Upper Connector 31 and the Upper Coil Transition Section 36 . As an assembled unit, the six components of the Coil Assembly will have a structural stiffness modulus as the assembly length changes. This Coil Assembly stiffness modulus is to be considered in conjunction with the Tensioning Assembly that is shown in FIG. 4 .
Referring to FIGS. 4 and 5 , the Tensioning Assembly the main body of a Riser Pipe 32 is attached to the Upper Connector 31 . Also, an engineered Upper Structure and Connector 38 is attached to the Upper Connector 31 . The Upper Structure and Connector 38 has two functions: The first function is to transmit the forces from a Tensioning Rod 39 to the Upper Connector 31 . The second function is to provide a proper connection for the Tensioning Rod 39 .
In one embodiment, this connection has a gimble configuration so that the Tensioning Rod 39 can perform properly. The displacement that occurs at the top of the overall Coil Section is expected to be more than the displacement that occurs at the bottom. This occurs because the base of the Coil Section is fixed by the Lower Connector 28 attachment to the riser base 26 , while the top of the Coil Section 27 responds to main riser length changes and offsets. This gimble arrangement can also be configured so that the Tensioning Rod 39 can be disconnected using subsea intervention practice. The reason for this is so that individual Tensioning Units 40 can be recovered for repair or replacement without having to recover and replace the entire Tensioning Assembly 30 . As will be explained later, the force that is developed by the Tensioning Rod 39 is provided by compression of gas that is acting on the piston 55 that is attached to the lower end of it, and confined within the Tensioning Unit 40 .
Each Tensioning Unit 40 is configured so that it is long enough to satisfy the particular application stroke needs, including additional length that may be considered appropriate by the system designers. The diameter of this cylinder is determined by the combination of contained gas compression pressure that is acting on the Tensioning Rod 39 piston's net area and the Tensioning Rod's tensile force that is required for the application. It is this Tensioning Rod tensile force, working in unison with the rods of the other Tensioning Units' rods' tensile forces that provides a significant portion of the Coil Section 27 stiffness modulus that is required as the system stroke length changes take place.
The Tensioning Auxiliary Pressure Unit 41 is an integral element to the Tensioning Unit 40 . This unit provides additional compressed gas volume that is in direct communication with that of the Tensioning Unit's compressed gas volume. This configuration permits the Tensioning Rod 39 to make the long stroke length changes without causing excessive compressed gas pressure changes. If this were not performed in this way, the rod load changes could be excessive, resulting in excessive changes in the riser top tension, which could lead to riser fatigue failure. The positioning of the individual Tensioning Units 40 around the Upper and Lower Connectors 31 and 28 is important. As a minimum, they should be placed so that they work in unison. This will prevent any excessive unbalanced loads on these two connectors 31 and 28 . Since the Host Facility lateral movements can occur in any direction, the number of Tensioning Units 40 and their placement should preferably satisfy this requirement. Evaluation of each application will reveal the appropriate arrangement.
FIG. 5 shows a representative plan view of an assembled Coil Section 27 that uses four Tensioning Units 40 . As shown in FIG. 4 and FIG. 8 , the Tensioning Unit 40 is also provided with a Sea Chest 42 . It is connected to the underside of the rod piston element that is contained within the Tensioning Unit 40 . The Sea Chest 42 provides the important function of pressure balancing the Tensioning Unit 40 . Local seawater pressure will be allowed to act on the underside of the rod piston and on the top of the rod. By using this pressure compensation method, the compressed gas pressure that is required to charge the cylinder of Tensioning Unit 40 and the cylinder of Tensioning Auxiliary Pressure Unit 41 is reduced roughly by the equivalent seawater pressure at the application depth. This provides important design and system performance efficiency. The Sea Chest 42 can be used to provide an inhibited fluid that is displaced into and out of the underside of the Tensioning Rod 39 and its connected piston as it moves in and out of the cylinder of the Tensioning Unit 40 in response to the Host Facility movements. This arrangement not only serves to eliminate the possibility for hydraulic block of the mechanism, but it reduces the possibility for unwanted corrosion or debris from affecting performance of the Tensioning Unit. At the base of the Tensioning Unit, the Lower Structure Connector 43 is provided. This item transmits Tensioning Unit 40 loads into the Lower Connector 28 . Preferably, it will have a gimble feature and disconnect capability for the same reasons as described previously for the Upper Structure 38 .
Operation
Referring to FIG. 1 through FIG. 5 , the way in which the Coil Section 27 works will now be summarized. The lower connector 28 is attached to a mating connector that is contained within a riser base. The riser base is structurally attached to the seabed, resulting in the lower connector 28 being a fixed point that is near the seabed. The bottom of the main riser pipe contains a mating connector for the upper connector 31 .
As the Host Facility moves, the top of the main riser pipe, which is connected directly to the Host Facility, moves with it. This movement is transmitted immediately via the main riser pipe into the Upper Connector 31 . This causes the spacing of the Coil Section coils to increase for Host Facility motions that tend to make the riser system length increase. As this coil spacing increases, coils provide a resisting force to the movement that is transmitted into the upper Connector 31 . Also, the tensile force of the tensioning rod 39 of the Tensioning Unit 40 is maintained, increasing somewhat as coil spacing increases. This action maintains a near constant load that also resists this Main Riser pipe movement, as the load is transmitted into the upper connector 31 . The load of the combined coils and Tensioning Units' 40 are transmitted into the Upper Connector 31 , and are in turn transmitted into the main body of the riser pipe. This Coil Section and main riser pipe loading increase results in an increasing tension load at both the bottom and the top of the riser that is predictable for the riser system. This helps ensure riser system design integrity. Since the fundamental purpose for the riser system is to provide pressure isolation for the fluid that is transmitted through it, maintaining this riser integrity is important. For Host Facility movements that tend to shorten the riser system length, the changes that occur are exactly the opposite of those changes that were just described for movements that tend to lengthen the riser system.
This concludes the detailed description of the Bottom Tensioned Riser system. By placing the top tensioning equipment in the lower section of a deepwater riser, the loads that are carried by the Tensioning System are reduced by an amount that is roughly equal to the weight of the riser in water. Moreover, a Coil Section 27 , which is placed in the lower part of a riser, can be used to efficiently control riser top tension loads while accommodating the Host Facility motions.
Representative BTR System examples are further discussed in Appendix I and Appendix II. The results of Model Experiments are provided in Appendix III. A rudimentary description of the installation of a BTR System is presented in Appendix VI.
Scope
From the foregoing description, it will be observed that numerous variations, alternatives and modifications will be apparent to those skilled in the art. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the manner of carrying out the invention. Various changes may be made in the shape, materials, size and arrangement of parts. Deepwater production risers range in pipe diameters from 3-inch through 36-inch. They are used in water depths (length) ranging from a few thousand feet to more than ten thousand feet. Carried fluid internal pressure may range from 1,000 psi to more than 20,000 psi.
Moreover, equivalent elements may be substituted for those illustrated and described. Parts may be reversed and certain features of the invention may be used independently of other features of the invention. For example, the common application for the BTR System will be steel and steel alloy materials. Other metallic materials, such as titanium, can be used. Composite type materials, such as those that are based on high strength, lightweight strands like Kevlar, also may be used in the future. The invention may also have applicability to the Ocean Thermal Research Program. It may ultimately lead to the need for long life and deep risers that are suspended from a surface facility. These risers also need be to be stabilized against lateral current forces, while managing riser top tensioning loads. This is just what the BTR System does. However, as presently configured, the BTR System is for high pressures and relatively low rates. Energy recovery that is based on the temperature differences between shallow water and deepwater will likely require very high seawater throughput rates at low pressures. The BTR System configuration may look different, but the principles would be the same. Thus, it will be appreciated that various modifications, alternatives, variations, and changes may be made without departing from the spirit and scope of the invention as defined in the appended claims. It is, of course, intended to cover by the appended claims all such modifications involved within the scope of the claims.
Appendix I
Worked Examples of Bottom Tensioned Riser (BTR) System
Referring to Appendix FIG. 1 , the U.S. Provisional Patent Application filed on Apr. 26, 2002 under Ser. No. 60/375,619, the BTR System and its key relationships are shown. These relationships are used in Appendix Table 1. All subsequent references to figures and tables in this appendix will be with respect to the U.S. Provisional Patent Application filed on Apr. 26, 2002 under Ser. No. 60/375,619. The examples provide simple static solutions for 4-inch through 14-inch riser and Coil Section pipe sizes in 6000 feet of water. This type of global, static solution information is representative for the initial riser approximations. Thus, the solutions are only indicative of the first step forward for doing a full riser analysis and design. These subsequent steps, which are beyond the scope of concept feasibility assessment, should include appropriate riser dynamic analysis in the frequency and time domains, use the predicted hull motions at the Host Facility attachment point, and apply appropriate hydrodynamic and modeling for the riser system. Also, static and transient multiphase product hydraulic simulations, and inclusion of the riser changes that will occur as a result of related thermal effects—especially for high temperature and pressure conditions will require analysis. However, based on previous experience, it is believed that these simple initial static results are sufficiently representative to reach conclusions about this new riser concept based on the results of these worked examples.
Referring to Appendix Table 1, this initial information results in the wall thickness estimate for a given grade of material, which is steel of Grade X60 in this case. The pipe code that is used is B31.4, with the wall thickness shown for each of the line sizes. For convenience, it is assumed that the riser pipe and coil pipe is made using the same material. It is feasible to use different materials for each, and this could result in optimized solutions. The single coil properties are defined, and items are specified or calculated as shown in the Table. Where applicable, the specific figure number and equation that is used to do each calculation is provided for reference. The global system parameters are then specified for the particular case. This provides an estimate for the number of individual coils that are required to satisfy these global conditions, and the Stiffness Modulus for the number of pipe coils that are used in the Coil Section. As described earlier, these are approximate solutions only. The reason is that engineering solutions for this type of system are not yet matured for detailed design purposes. The next section provides the calculations for the Tensioning Units that are used with the Coil Section 27 . This case assumes that a “closed system” is used for the cylinder and rod piston elements, along with an auxiliary cylinder. This is performed to efficiently manage the gas compression. Further discussion about this is provided in Appendix II.
The focus on this work has been primarily on the 12-inch riser size, so the tensioning assembly sizes and rod forces are best suited to using four of these tensioning units. As can be seen in Appendix Table 1, the number of units is artificially reduced for the smaller sizes. If this were not performed, riser top tension loads would be too high because the tensioning unit rod loads would be too high. In actual practice, smaller tensioning units would be configured so that a minimum of three units, perhaps four would be used. The larger number of units is necessary to ensure that the rod loads are properly distributed around the Coil Section top connector. For this work, it is assumed that the rod piston cylinders are completely efficient. This is rarely a good assumption, and it is common engineering practice to handle this matter during detailed design of equipment. With the Tensioning Unit Stiffness Modulus determined, the overall Coil Section Stiffness Modulus is then established, accounting for the stiffness of both the coils and the tensioning units. The Stiffness Modulus for the Riser Pipe itself is then calculated as referenced in the Table. The combined Stiffness Modulus for the Riser Pipe and the Coil Section 27 is also calculated as shown in the Table.
The weights that are represented in this Table are essentially solutions in air. In actual practice, a very wide range of weights will be possible in a given situation. This is because individual pipes will displace a volume of seawater, and buoyant forces will partially offset the pipe weight in air. However, the product in the riser will add weight, while coatings added to the pipe usually decrease the pipe weight in water. Experience has shown that for initial approximations, just using the pipe weight in air is a reasonable initial assumption pending availability of detailed information. It is believed that this weight in air assumption will provide reasonable first approximations for assessing the BTR System.
With the riser system stiffness modulus established, the conditions for the riser when the Host Facility is in the neutral, or no offset position are satisfied. The means for doing this is to apply an initial top tension in the riser that exceeds the weight of the riser itself. This allows the Host Facility to move around in its neutral position, and it provides a top tension load that exceeds the riser self weight. This additional tension is needed to structurally stabilize the riser during the wide range of environmental loadings to which it will be subjected, even when the Host Facility as at or near its no offset position. For this case, it is assumed that one third of the Coil Section 27 extension capability is used to provide this pre-tensioning. This fixes the top tensile stress in the riser at the level at which it will be for the predominant time period of its useful life. These calculations are shown in Appendix Table 1. Similarly, the next condition that should be satisfied is when the Host Facility is offset to its predicted extreme offset position. These calculations, including the resulting riser top tensile stress, are shown in the Table.
Maintaining a consistent set of assumptions, these calculations can be repeated for a wide range of possible water depths. An example for a 12-inch BTR System is provided in Appendix FIG. 2 . This is performed to demonstrate that the BTR concept is suitable for a wide range of water depths. Use of the closed system Tensioning Unit method causes the riser top tensile stress to increase as the Host Facility moves from the no offset position to the maximum offset position. This appears to be a manageable level of stress increase. However, if detailed riser design determines that this is not acceptable, an open system Tensioning Unit can be used to maintain a near constant riser top tensile stress across the range of Host Facility movements. However, this open system Tensioning Unit design is expected to add complexity and cost to the BTR System.
A few final comments are provided about the loads that will occur at the lower end of the BTR System. The Coil Section 27 will be subjected to a wide range of loads. Since it is located under the main riser body, these loads will be relatively small. This is why the focus of this discussion is the riser top loads, which are quite large in deep water. Even so, the Coil Section loads should be properly identified and detailed designs provided to meet these load conditions. When these bottom-located Coil Section loads are compared to those of a comparable surface located, stroke-providing tensioning unit, where the surface unit carries the riser weight and its over pull, the true value of a BTR riser system and the Coil Section design becomes immediately apparent. Since the Coil Section is located at the bottom of the riser, the impact of providing a long stroke unit is minimal. Providing a long stroke unit at the surface is costly, and interfacing a unit like this with the topsides can become complex to the extent that it may not be feasible to do it.
Appendix II
Tensioning Assembly Cylinder and Rod Piston Configurations and Comparisons
This is a summary of the work that was performed to select one preferred configuration for a Coil Section 27 closed system Tensioning Unit. There are three fundamental ways in which a subsea cylinder and rod piston unit can be configured. These three methods are represented in Appendix FIG. 3 and FIG. 8 herein. Unless otherwise indicated, all references to figures and tables in this appendix will be with respect to the U.S. Provisional Patent Application filed on Apr. 26, 2002 under Ser. No. 60/375,619.
A basic cylinder and piston rod option is shown in FIG. 8A . The work that was performed previously in conjunction with the Coil Section 27 load determination established representative types of rod loads and stroke lengths that would be needed for a Tensioning Unit. The focus of this effort was on a 12-inch riser pipe size for 6000 feet of water. This provided first approximations of a required rod force of between 100,000 pounds and 130,000 pounds (when combined with coil properties and four tensioning units, this will result in top tension loads (over pull) up to about 500,000 pounds. At 6000 feet, the required stroke length is about 360 inches. For the purposes of this work, a minimum stroke length of 480 inches was assumed.
In a perfectly pressure compensated system (i.e., frictionless), gas pre-charge at the surface can be performed so that the cylinder pressure at subsea application depth is exactly the same as it is at the surface (See FIG. D-13, equations (1) through (3)). Thus, cylinder wall thickness requirements can be determined for the application. In an actual design, a higher gas pre-charge than the “perfect” pressure would be used. This is performed because some extra pressure is required subsea for two reasons: First, the rod lubricator that is located at the top of the cylinder, and the rod piston element, where it contacts the cylinder wall, exhibit real world friction that must be overcome. Second, the rod is long and slender. Thus, the piston force should be kept high enough that it ensures that the rod will be “pulled” into the cylinder, and not “pushed” into it as the Tensioning Unit stroke is decreasing. If the rod were pushed, it could easily buckle. This could lead to failure of the Rod and Cylinder. For this comparison, the perfect gas pre-charge pressure is assumed for all options, recognizing that all configurations will require a pressure greater than this for actual design.
As can be seen in Appendix FIG. 3 and FIG. 8 herein, as the piston rod is stroked out, the gas in the cylinder is compressed. The solution to this problem is easily determined using the compressed gas pressure that will not over pressure the cylinder or over stress the rod as it develops the required tension load as it approaches the required rod stroke length.
Appendix FIG. 4 provides the results of this solution for the basic cylinder and piston rod option of FIG. 8A herein. However, as shown in Appendix FIG. 4 , the cylinder length is twice as long as the stroke length objective of 480 inches to prevent over pressuring the cylinder.
The auxiliary cylinder option uses an auxiliary cylinder and is shown in the middle of Appendix FIG. 3 and FIG. 8B herein. This configuration achieves the same purpose as the first option, but because the added gas compression volume is provided in parallel, the cylinder pressure increases more slowly. The results of this solution are shown in Appendix FIG. 5 . The configuration length remains within the stroke length objective of 480 inches.
A “carrier pipe” option, which is basically placing the main cylinder within another cylinder to provide the added gas compression volume in parallel to the main cylinder, is shown on the right side of Appendix FIG. 3 and FIG. 8C herein. The results for this solution are provided in Appendix FIG. 6 . The configuration length remains within the stroke length objective of 480 inches.
An overall summary comparison of the “attributes” for these three Tensioning Unit options is provided in Appendix FIG. 7 . It is clear that the configuration that is represented in the middle of Appendix FIG. 3 is the preferred way to approach the design for the Tensioning Unit assemblies.
In closing on this topic, it should be noted that no allowance has been made for the weight of these Tensioning Units in the Coil Section 27 weight estimate. The reason for this is the possibility that these units will be of very low weight in water, perhaps even buoyant (tendency to float). At this point, it is thought conservative to exclude their weight from the example calculations.
Appendix III
Summary of Model Experiments
A series of simple, but representative, experiments were performed to assess the BTR concept. The experimental set-up is shown in FIG. C-1 of the U.S. Provisional Patent Application filed on Apr. 26, 2002 under Ser. No. 60/375,619. All subsequent references to figures and tables in this Appendix will be with respect to the U.S. Provisional Patent Application filed on Apr. 26, 2002 under Ser. No. 60/375,619. Each Experiment is characterized by investigating the physical deflection of the Coil Section 27 with different weights attached to the apparatus. The primary difference between each of the experiments is a change in the Coil Section diameter. For each Test Condition, engineering calculations were performed based on representative materials and the model geometry. These measured and calculated results were then compared to one another. Results of the Experiments are summarized in Appendix FIG. C-2 through Appendix FIG. C-22. The following conclusions may be made:
First, the calculated deflection values (Coil Section stretch) were consistently over-predicted. By direct inference, this resulted in consistent under-prediction of the Coil Section Modulus K. Second, at very low loadings on the model, the Coil Section Modulus values demonstrated significant high variations. Some of this can be readily explained by limitations of the model apparatus, such as friction on the weight/pulley assembly being inconsistent. Regardless, low-load measurements are suspect. Third, at higher end loadings, the convergence of Coil Section Modulus measured and calculated value seems to be more consistent. However, the Coil Section tends to retain more of its stretched length with the higher loads. Even so, the Coil Section appears to retain its basic modulus value. This aspect warrants further investigation before any full-scale application is considered. Fourth, the agreement between measured and calculated deflections across Coil Section diameters supports the basic analytical procedures. Given that general engineering handbook properties are assumed representative for hardware store supplied materials, confidence in the methods that were used is bolstered.
At the end of Experiment 1, an attempt was made to “fail” the Coil Section at the maximum offset position of the model. This model offset is much more than would occur in actual practice. It is noteworthy that although this was quite a severe condition, and the Coil Section was permanently extended, nothing came apart. Although this should not be construed as a design attribute, it indicates that the Concept does provide some forgiveness for conditions that may exceed design expectations.
Much was learned about the model apparatus and its limitations during the set-up for Experiment 1. Since this work was performed solely for purposes of simple assessment of a concept, no costly effort was made to overcome observed deficiencies.
Appendix IV
Brief Summary of Recent Deepwater Developments
Riser concepts and designs have evolved along with the various types of offshore field developments. Field development configurations are dependent on water depth, reservoir size and properties, fluids properties and the environmental conditions. A summary of Gulf of Mexico representative field development methods is provided in FIG. E-1 of the U.S. Provisional Patent Application filed on Apr. 26, 2002 under Ser. No. 60/375,619. All subsequent references to figures and tables in this Appendix will be with respect to the U.S. Provisional Patent Application filed on Apr. 26, 2002 under Ser. No. 60/375,619. Given the nature of well development drilling, completion, production and well work over operations, the field developments that use Conventional Platforms have established a long and proven track record for water depths approaching 1500 feet of water. These platforms are rigid structures that are designed not only to support topsides equipment, but they also fully resist the large environmental loads. The well risers, consisting of the surface conductor, drill casings, production casing and production tubing are supported by the surface conductor, which is anchored, usually by pile-driving it, into the seabed. Conductor guides, which are imbedded within the platform structure, are spaced to prevent the conductor from buckling due to its self and supported weights 4 . This arrangement provides the desirable hands-on access to the surface wellhead equipment. This “dry” well equipment access exists throughout the field life. In the relatively shallow water, export and import risers can be “stalked-on” to the platform with the assistance of divers. However, as water depths increase, the J-tube pull-in riser is generally preferred. This is because the need for diving support is eliminated. As water depths increase, commercial diving support is feasible to a little more than 1000 feet of water. However, saturation diving, which is necessary beyond 180 feet of water, is costly and there can be safety issues to consider as well. Even so, the stalk-on riser method can be used when necessary, with water depth limitations as noted.
As water depths continue to increase, the Compliant Tower Jacket (CTJ) 5 can be an alternative field development method. This name is used because it is a flexible structure. This flexibility reduces the environmental loads that would need to be accommodated if it were of the more rigid conventional platform design. Thus, for a given water depth, the CTJ contains less steel, resulting in cost advantages when compared to conventional platforms. Above the water line, the CTJ looks much like the conventional platform, providing the “dry” well equipment features, with support to this equipment still being provided by the surface conductors. As the water depth increases, the depth to which the surface conductor is anchored into the seabed increases. Due to soft bottom conditions that prevail to several hundred feet below the seabed in many parts of the Gulf of Mexico, proper placement of these conductors using pile-driving technology can be a challenge. J-Tube risers can be used for export and import risers for many cases, but stalk-on or steel catenary risers are also viable alternatives.
The Tension Leg Platform field development method originated in the early 1970's. This concept introduced the floating hull method as a way to keep the Host Facility cost from escalating due the large quantities of steel that are required by bottom-founded structures as the water depth increases. A bottom-founded structure requires that the amount of steel that is needed just to support its own weight will increase geometrically with water depth. The TLP, combined with highly tensioned mooring tendons, reduces the amount of heave (up-and-down) motions to a much smaller amount than would exist if the hull were spread-moored. This feature makes it feasible to attach the well system equipment to the TLP, retaining “dry” equipment features. However, even though the heave motions are small, the TLP will still move laterally due to its response to environmental loadings. Thus, the riser top-tensioning equipment is designed to provide a strokelength to accommodate the small up and down motions as well as the riser length change that occurs as the TLP moves laterally. This top tensioning assembly stroke length capability prevents the riser from being over-stressed as the TLP moves in response to the environment and load changes on the TLP itself. Also, the riser top tensioning assembly should maintain a relatively constant tension along with the stroke length changes. This is performed to prevent the large stress cycles that could otherwise limit fatigue life of the riser. The riser tensioning systems add complexity and weight to the Host Facility, but allow retaining the “dry” features. Several TLP's have been installed since the 1980's, and their design methodologies have matured accordingly 7 .
The pace at which the need for field developments in deepwater has increased rapidly. In the early 1990's, it was thought that commercial viability of field developments would probably be in the range of 3000–4000 feet of water in the Gulf of Mexico. Since TLP technology was viable to these water depths, it was thought that the TLP, top-tensioned risers, and steel catenary risers could meet most, if not all, of these needs. Even so, there remained concerns about the high cost of these systems, primarily due to the way that tendon size and weights escalate beyond 3000 feet of water. New technology approaches to address these TLP needs were initiated. Some of the most notable include the use of new materials to reduce topsides weight and consideration for the use of new materials for tendons, production, and drilling risers 8,9 . In the interim, exploration drilling has continued to identify field development opportunities well beyond 4000 feet. Thus, while the TLP well and export and import riser needs can be met efficiently using top-tensioning methods to about 4000 feet, the TLP approach remains challenged for the deeper water applications.
During the mid-1980's, a new type of riser system was conceived to address some of the disadvantages that exist with the top-tensioned export and import risers. It was called the Steel Catenary Riser (SCR). This name is based on the shape that the riser takes as it bridges between its connection point on the Host Facility to an offset position that is located on the seabed. It offers technical and cost advantages for those top-tensioned riser applications that do not require vertical access. Since vertical access is needed for drilling and completion risers, the SCR approach is limited to the export and import riser applications. First commercial use of the SCR risers was for the Auger TLP export pipelines 6,10 . Following this success, SCR's continue to meet many deepwater field development needs.
Also, during the mid-1980's, a new type of hull system that can be used for the Host Facility was conceived 11 . It is referred to as a Deep Draft Caisson Vessel (DDCV). It is also called a “Spar”, which refers to its up-right appearance when it is installed, but before the topsides have been installed. The DDCV has been used for some field developments that are in water depths for which the TLP or other methods are too costly. The riser systems for a DDCV can use buoyancy in the upper riser section, which is guided through the central section of the hull. This method not only meets the requirements for top tensioning of each well riser, but it reduces the load that the hull carries. The Spar drilling riser may be top-tensioned using an approach that is similar to the one that is used for the TLP. The Spar surface well equipment retains “dry” access to the wells. Export and import SCR's, which do not require the vertical access, are commonly attached to the hull. In some circumstances, even the well equipment may be provided with top-tensioning equipment rather than using buoyancy in the riser. The Spar hull, which may be either spread moored or taut moored, provides heave motions that are somewhat similar to those of the TLP, but the Spar can handle topsides weight increases more efficiently than a comparable TLP. Thus, the Spar mooring system cost does not increase geometrically as the water depth increases. The Spar riser stroke length is considerable for the extreme design events, but topsides can be configured to accommodate these clearance, or headroom, needs. It is thought that the DDCV/Spar approach may continue to be cost efficient as exploration success in ultra-deep water continues.
With continuing increase of the water depth and additional topsides payload capacity requirements, a Host Facility called a Semi-submersible-shaped Floating Production System (FPS) 12 can provide cost advantage over a DDCV. Although FPS's have been used many times for field developments in other areas, especially offshore Brazil, they have not yet seen frequent application in the Gulf of Mexico. The spread-moored FPS provides favorable motions for producing operations, but these motions are not compatible with the use of “dry” well equipment due to the riser stroke challenge. Thus, they are most often used with subsea equipment and “wet” wells as represented in this drawing. Mobile Offshore Drilling Units (MODU's) are used to drill and complete the subsea wells that are laterally offset from the FPS. Since the FPS is offset from the subsea wells, the SCR's can be routed directly to the Host Facility and connected to the hull. Another variation on the FPS is to locate the subsea wells directly under the FPS. In this configuration, the FPS can be equipped with a drilling rig that can meet these “wet” subsea well needs. Floating well drilling and completion methods are used for these wells. SCR's that are needed for export are connected directly to the hull. However, seabed manifold equipment is commonly used to commingle production so that a reduced number of SCR's can be used for the import riser duty. A flowline is run outward and away from the Host Facility. It is then routed through a 180-degree turn so that the SCR approach to the FPS is provided in a straight line.
Another type of floating system, referred to as a Floating Production Storage and Offloading (FPSO) system, has been used elsewhere, with application area environments ranging from quite benign to extremely harsh 13 . This particular configuration includes a new large diameter export riser concept 14 called a Helical-base Riser. It provides a means to meet the very long stroke requirements for a large diameter rigid riser (steel) that might be used with an FPSO system. The use of FPSO-based developments in the Gulf of Mexico has only recently been approved by the Minerals Management Service (MMS). Since the FPSO type system and its risers may be applied at some undefined time in the future, further discussion is premature.
Each of the previous field development methods are based on technology that is relatively mature, but ultimate field development costs remain high. A significant cost element remains the cost of meeting the riser system needs. Table E-1 of the U.S. Provisional Patent Application Ser. No. 60/375,619 filed on Apr. 26, 2002 provides a summary for the types of risers that have been discussed above.
Appendix V
BTR Performance
Overall BTR system relationships are shown in FIG. E-5, of the U.S. Provisional Patent Application filed on Apr. 26, 2002 under Ser. No. 60/375,619. All subsequent references to figures and tables in this Appendix will be with respect to the U.S. Provisional Patent Application filed on Apr. 26, 2002 under Ser. No. 60/375,619. Typical results for the riser top tensile stress that are provided in FIG. E-4B, indicate that the BTR system can provide efficient vertical riser solutions for deepwater applications. FIG. E-5 represents a summary of pertinent information that is individually developed as shown FIG. E-6 and FIG. E-7. The BTR system is directed to those deepwater riser duties that do not require vertical access. These duties are generally regarded as export and import risers.
The BTR concept could be used for some export and import riser applications with considerable benefit over present methods. The combinations of very deep water and the deep reservoirs can result in the need for handling very high pressure and temperature fluids. The BTR system provides a solution that is all metal. This is a very important advantage for the high pressure and temperature situations. Table E-2 (reproduced below) provides a summary list of advantages and disadvantages for the BTR concept.
TABLE 1
BTR Advantages & Disadvantages
Advantages
Disadvantages
Low Cost
New
Minimum impact on Host Facility Design
Requires New Design
Small Seabed Footprint
Methodologies
All Steel, Vertical Riser Design
New Challenges for
Small Top Tensile Loads for Full Range
Manufacturing,
of Host Facility Offsets
Transportation and
Coil Section can be Changed (if
Installation
necessary) Throughout Field Life
Demonstration of Life-of-
“Forgiving” Design if Host Facility
Field Materials behavior in
Motions are Different from those
Coil Section will need to be
Predicted
evaluated
Minimum number of Active Components
to Maintain or Repair
As can be observed from FIG. E-5 and FIG. 2 herein, the top tensioning assembly, including provision for accommodating basic riser length changes as the Host Facility moves, is placed in the lower part of the riser. By doing this, the top tension load is limited to that of the riser self weight, external environment loads on the riser, and the tension that is developed by the Coil Section 27 to provide structural integrity of the riser for these external loads. The really large differences between this approach and traditional top tensioning assemblies is that the BTR tensioning assembly does not need to carry the riser self weight and by virtue of the Coil Section 27 location, riser stroke length needs can be easily accommodated. This Coil Section 27 includes a combination of pipe coils and rod/gas pressurized cylinder assemblies.
As shown in FIG. E-6 and FIG. 10 herein, the Coil Section 27 includes a series of pipe coils. The purposes of these coils are primarily twofold: First, they provide product pressure containment and continuity from the main riser pipe to the riser base connection. Second, they provide the riser flexibility that allows the main riser body to move along with the Host Facility without incurring excessive riser top tensile stresses. The coil behavior is assumed to be similar to that of a spring coil that is made from a solid rod of a particular material 17 .
These relationships are recognized for their intended purpose, which is to provide reasonable first approximations for the evaluation of this new riser concept To account for this difference between a solid rod and a tube, an equivalent tube diameter is estimated using the cross-section moment of inertia equivalency as the means for approximating a solid rod diameter. Determination of appropriate tube coil relationships that can be used with confidence for Coil Section 27 design purposes will be necessary as a first step forward to mature this concept. Regardless, application of these solid rod principles is straight forward, and the first approximations should provide reasonable results.
The coil design boundaries are determined by the combination of application duties and manufacturing limitations. It is desirable to make the coil diameter as small as possible for at least two reasons:
First, the coil stiffness modulus is an inverse exponential relationship to the coil diameter. The smallest possible diameter provides the largest stiffness modulus. And the larger the stiffness modulus, the closer the Coil Section system modulus is to that of the main riser itself. Also, the smaller the coil radius is, the smaller the resulting seabed footprint. As discussed previously, this is desirable to simplify subsea architecture. The smallest feasible diameter can ease manufacturing, transportation, and installation requirements, which are directly related to costs and risks.
Second, the coil diameter needs to keep the pipe strain within acceptable design practice limits 18, 9 . This requirement is best met by increasing the coil diameter. Since application duty will also require accommodating pigging operations, the Industry criteria for minimum pipe bend radius, which is the same as that required for maximum strain, has to be followed.
FIG. E-6, FIG. E-7 and FIG. 10 herein summarize what the assembled coils, including the upper and lower transition sections, can look like to meet these objectives. Although there are many ways that can be used to solve the underlying geometry, the method that is provided in these drawings is straightforward and suitable for first approximations. Based on these relationships, single coil solutions vs. coil pipe outside diameter for the minimum pipe bend criteria are provided in FIG. E-7, FIG. E-9, FIG. E-10, and FIG. 10 herein This information is representative of maximum conditions.
The relationships for the closed system cylinder and rod assembly that are provided in FIG. E-11 can be used to determine this assembly Stiffness Modulus. Summary results are provided in FIG. E-14.
The Coil Section 27 components, as described earlier, result in the configuration and relationships that are shown on FIG. E-15. Although numerous possible solutions exist, it is assumed for this concept assessment work that four cylinder and rod assemblies are used. Also, the equipment design is based on the use of a sea chest to pressure balance the equipment at its subsea operating depth. This result provides efficient use of gas pressure that can be readily accommodated at both surface and subsea conditions and controlled and clean fluid displacement from the underside of the piston elements.
Appendix VI
BTR Installation
A representative description of the BTR system installation activities will not be given. The objective is to provide information about one way in which the BTR System could be installed. The method that is described should result in little interference with other activities that may be taking place on the Host Facility. Other installation methods may be preferred for other specific installation equipment and site-specific situations. The activities that are described are based on the use of installation equipment that reduces the amount of Host Facility assistance as much as is practical under the circumstances.
Modern deepwater installation equipment comes with fully equipped facilities that are needed for this sort of work. Such facilities include high capability dynamic positioning and station keeping systems. Even so, deepwater riser installation activities, including those described below, are often weather and water column current sensitive. Thus, the riser installation activities are progressed as the environment is determined to be in accordance with the pre-determined limits for each activity.
Initial Conditions
As shown in FIG. I-1 of the U.S. Provisional Patent Application filed on Apr. 26, 2002 under Ser. No. 60/375,619, the Host Facility is spread moored at its permanent location. All subsequent references to figures in this Appendix will be with respect to the U.S. Provisional Patent Application filed on Apr. 26, 2002 under Ser. No. 60/375,619.
1. The seabed riser base connector is pre-installed, 2. The riser top connector is pre-installed on the Host Facility, and 3. The riser installation aids are installed.
The riser top connector placement is shown on an out-board pontoon, but it could also be placed on the in-board side of the pontoon. This connector placement is shown below the water line, but it could also be placed at other locations, including a suitable connection point on the Host Facility that may be above the water line.
Coil Section
FIG. I-2 represents how the BTR Coil Section is transported from a land fabrication site to the field location on a cargo barge.
1. The Coil Section 27 is transported in a transportation frame. This frame is used to secure the Coil Section during transportation. It also provides structural strength to the Coil Section as it is lifted from the horizontal position into the vertical position. 2. The cargo barge is brought alongside a construction vessel that is equipped with a lifting crane. 3. The crane lifts the Coil Section into the vertical position (see FIG. I-3) until it is free of the cargo barge. 4. An auxiliary crane (not shown for clarity) on the construction vessel is used to assist with removal of the transportation frame. All materials having no further need in the field are loaded onto the cargo barge, and it is returned to port. 5. An installation vessel that is equipped to install the Main Riser and the Coil Section is brought to a location that is near the construction vessel, which continues to suspend the Coil Section in its vertical position. This is shown in the upper part of FIG. I-3. In this case, a reel-type vessel is used to install the Main Riser. The Main Riser and Coil Section could also be installed using a vessel that is outfitted for J-Laying pipe. It is also possible to use the Host Facility drilling rig to assist the Main Riser installation, but as previously mentioned, this assumed case is based on conducting the riser installation work with minimum interference with any other activities that may be taking place on the Host Facility. 6. As shown in the lower part of FIG. I-3, keelhaul rigging lines are run from the Riser Installation vessel to the top of the Coil Section. These activities can be performed using hard-hat diving because the water depth is relatively shallow, but it is also possible to use a remotely operated vehicle (ROV) to make the necessary connections as well. 7. The mating connector attaches to the bottom of the Main Riser and the top of the Coil Section is attached to the end of the Main Riser, which is suspended below the installation vessel. 8. Once the rigging is in place, the construction vessel crane lowers the Coil Section 27 , and the riser installation vessel begins picking up the weight of the Coil Section, resulting in the Coil Section being located beneath the Main Riser and its Mating Connector 9. The Main Riser is lowered to engage the Coil Section Upper Connector, and this connection is made using ROV assist techniques. As can be seen in the upper portion of FIG. I-4, the Coil Section 27 , Main Riser, keelhaul rigging lines, and construction vessel lowering lines are attached near the top of the Coil Section upper connector. Riser loads are now carried by way of the Main Riser body. 10. The connector is tested to confirm integrity. 11. Then, each of the handling lines is disconnected from the Main Riser using ROV methods. This results in the arrangement that is shown in the lower part of FIG. I-4. 12. The riser and Coil Section 27 can be lowered towards the seabed and the Construction Vessel released. 13. As the Main Riser reaches a pre-determined water depth and riser length, it is “hung-off” on the installation vessel. 14. In this reel-type installation vessel example, the Main Riser pipe is continuous, so it is cut off just above the hang-off point. 15. The Riser Top Connection Assembly is then attached to the Main Rise, pipe. This length of the Main Riser pipe and the Coil Section 27 , including consideration for pipe stretch due to self-weight and contraction of the pipe due to the cold water column, is shorter than the connection length between the riser base and the Host Facility riser top connection point.
Thus, after the Coil Section 27 is locked onto the seabed riser base as described further below, it will require an over pull at the top of the riser that is in excess of the weight of the Main Riser and Coil Section as it is landed at the Main Riser to the Host Facility connection point. This over pull, which is performed once the Coil Section 27 is readied for extension provides the Main Riser pre-tensioning that is required for the Main Riser structural stability when the Host Facility is located in its neutral, or no-offset position. Once the BTR is connected to both the Riser Base and the Host Facility, the Coil Section 27 extension and retraction accommodates Host Facility motions at its neutral position. At the same time, it maintains the riser top tension at the appropriate level as these motions take place. Although a separate handling line could be used for remaining Installation vessel activities, it is efficient to use the excess riser pipe that is still on the installation vessel.
As described above, the Main Riser is cut off above the Main Riser hang-off point. Thus, a riser handing assembly, which is robust, flexible, and capable of handling the weight of the riser, is attached to the end of the pipe that is still on the installation vessel. The flexibility is necessary to ensure that the Main Riser pipe is not over stressed or otherwise damaged during any of these handling operations.
16. This riser handling assembly is connected to the Riser Top Connection Assembly, 17. The installation vessel pipe tensioning equipment and excess riser pipe is used to lower the top of the Main Riser as necessary. If required for any reason, this equipment can also be used to raise the Main Riser. As mentioned previously, there are other methods for doing these activities. The preferred method is determined based on vessel specific information and installation engineering design. 18. Continuing with this example, the riser is in its suspended position and the Main Riser Installation vessel is maneuvered close to the Host Facility as shown in FIG. I-5. 19. The riser handling equipment and riser installation line that is located on the Host Facility is hauled over to the riser top and attached to the riser top connection assembly. Since this is usually a very heavy chain, appropriate rigging and handling equipment is used to assist making this connection. The connection activities may be aided by the use of hard-hat diving and ROV equipment. 20. This connected equipment is then used to take up the riser weight using a sequence of coordinated steps. These steps include: moving the installation vessel toward the Host Facility; and as this is being performed, reducing the riser weight that is carried by the installation vessel and increasing the riser weight that is carried by the Host Facility riser installation line is increased. The steps are complete when the Host Facility Riser Installation Line carries all of the riser weight as represented on the left side of FIG. I-6. 21. The Main Riser installation vessel Line and any related installation aids are disconnected from the Main Riser. 22. The Riser Installation vessel can then be released. 23. The Host Facility is positioned on its mooring so that the Main Riser and Coil Section 27 are located above and directly over the Riser Base Connector. 24. The Coil Section 27 , which contains the upper portion of the Riser Base Connector, and the Main Riser are lowered onto the riser base connector, locked, and tested. These guideline-less connection methods are commonly used to install well and subsea equipment in deepwater. Since these connection activities occur in deepwater, ROV and related tooling methods are used exclusively to assist these Riser Base connection activities. An ROV is then used to perform additional duties after the BTR System is connected to the Riser Base. These may include:
disabling Coil Section locking mechanisms, removing various installation aids, and confirming readiness of the Coil Section Tensioning Units for the riser pre-tensioning activity.
25. For example, it may be determined that more or less Tensioning Unit cylinder gas pressure may be required to meet the actual Main Riser weight in water top tensioning objectives. The reason for this is that the actual riser weight in water may not be exactly as estimated. Any differences are usually due to the combination of engineering assumptions, manufacturing tolerances, and other minor deviations that may be unique to the installation site. 26. Once final adjustments are finished, the conditions that are represented on the left side of FIG. I-6 exist. 27. The Host Facility Riser Installation Line is used to pre-tension the Main Riser and the Coil Section 27 . Lifting the Riser Top Connection to the appropriate level does this. 28. The Riser Top Connection is then landed into the docking receptacle as represented on the right side of FIG. I-6. 29. Auxiliary handling lines from the Host Facility may be used to assist landing the Riser Top Connection Assembly in the Host Facility docking receptacle. 30. Once the Main Riser is docked in the receptacle and the Riser handling equipment is removed, the BTR installation activities are essentially complete. Any remaining Host Facility piping bridging between the top of the riser and Host Facility piping is installed and tested as appropriate. Once all risers that are to be installed are completed, related Host Facility Installation Aids would typically be removed.
LIST OF REFERENCES
All of Which are Hereby Incorporated by Reference
1—Moran, K.:“Deepwater Technology in the International Ocean Drilling Program”, Offshore Technology Conference (1–4 May, 2000), OTC 12179
2—Moyer, M.C., Barry, M.D., Tears, N.C.: “Hoover-Diana Deepwater Drilling and Completions”, Offshore Technology Conference (Apr. 30–May 3, 2001), OTC 13081
3—Bates, John B., Kan, Wan C., Allegra, Allen P., Yu, Allen: “Dry Tree and Drilling Riser System for Hoover DDCV”, Offshore Technology Conference (Apr. 30–May 3, 2001), OTC 13084
4—Stahl, B., Baur, M. P.: “Design Methodology For Offshore Platform Conductors”, Offshore Technology Conference (May 5–8, 1980), OTC 3902
5—Simon, J. V., Edel, James C., Melancon, Charles: “An Overview of the Baldplate Project”;, Offshore Technology Conference (May 3–6, 1999), OTC 10914
6—Enze, C. R., Brasted, L. K., Arnold, Pete, Smith, J. S., Luyties, W. H.: “Auger TLP Design, Fabrication, and Installation Overview”, Offshore Technology Conference (May 2–5, 1994), OTC 7615
7—Recommended Practice for Planning, Designing, and Constructing Tension Leg Platforms, API Recommenced Practicee 2T, Second Edition, August 1997
8—Hanna, Shaddy Y., Salama, Mamdough M.: “New Tendon and Riser Technologies Improve TLP Competitiveness in Ultra-Deepwater”, Offshore Technology Conference (Apr. 30–May 3, 2001), OTC 12963
9—Botker, Stig, Storhaugh,Turid, Salama, Mamdough M.: “Composite Tethers and Risers in Deepwater Field Development: Step Change Technology”, Offshore Technology Conference (Apr. 30–May 3, 2001, OTC 13183
10—Hays, P. R.: “Steel Catenary Risers for Semisubmersible Based Floating Production Systems”, Offshore Technology Conference (May 6–9, 1996), OTC 8245
11—Halkyard, John, Horton, Edward H.: “Spar Platforms for Deep Water Oil and Gas Fields”, MTS Journal, Vol. 30, No. 3, 3–12
12—Blincow, R. M., Whittenburg, L. A., Pickard, R. D.: “GB 388—An Independent's Approach to Deepwater Development”, Offshore Technology Conference (May 1–4, 1995), OTC 7842
13—Leghorn, J., Brookes, D. A., Shearman, M. G.: “The Foinaven and Schiellion Developments”, Offshore Technology Conference (May 6–9, 1996), OTC 8033
14—McShane, Brian M., Bruton, David A. S., Palmer, Andrew C.: “Rigid risers for floating production systems in deepwater field developments”, Pipes & Pipelines International, January–February 2000
15—Design of Risers for Floating Production Systems (FPS's) and Tension Leg Platforms (TLP's), API Recommended Practice 2RD First Edition, June 1998
16—Serta, Otavio B., Longo, Carlos E. V., Roveri, Francisco E.: “Riser Systems for Deep and Ultra-Deepwaters”, Offshore Technology Conference (Apr. 30–May 3, 2001), OTC 13185
17—Baumeister, Theodore, Avallone, Eugene A., Baumeister III, Theodore: “Marks'Handbook for Mechanical Engineers”, Eighth Edition, 1978, pages 8–76/8–77
18—Design, Construction, Operation, and Maintenance of Offshore Hydrocarbon Pipelines (Limit State Design), API Recommended Practice 1111, Third Edition, July 1999
19—Kopp, F., Peek, R.: “Determination of Wall Thickness and Allowable Bending Strain of Deepwater Pipelines and Flowlines”, Offshore Technology Conference (Apr. 30–May 3, 2001), OTC 13013
20—Byle, Steven M.: “Tension control device for tensile elements”, U.S. Pat. No. 6,190,091, Feb. 20, 2001
21—Davies, Richard; Finn, Lyle D., Pokladnik, Roger: “Riser tensioning device”, U.S. Pat. No. 5,758,990, Jun. 2, 1998 | A new marine oil production riser system for use in deepwater applications is disclosed. An efficient means for accommodating movements of the host facility, while maintaining riser top tension within the limits for long-term riser performance. Long riser stroke lengths can be accommodated without requiring complex interfacing with the topsides. The riser assembly comprises: a generally extendable substantially non-vertical section having an upper end adapted to be in flow communication with a generally vertical marine riser carried by a facility floating on the surface of a body of water, and having a lower end adapted to be in flow communication with a fluid source on the seafloor; and tensioning means, mechanically connecting the upper end of the marine riser with the lower end of the marine riser, for biasing said ends towards each other. The tensioning means comprises: a cylinder having one end open to sea pressure, having an opposite end sealed from sea pressure, and connected to one end of the marine riser; a piston within the cylinder disposed for movement within the cylinder; and a piston rod passing through the opposite end of the cylinder and having one end connected to the other end of the marine riser. | 4 |
CROSS REFERENCE TO RELATED APPLICATIONS
This application is the US National Stage of International Application No. PCT/EP2006/064458, filed Jul. 20, 2006 and claims the benefit thereof. The International Application claims the benefits of German application No. 10 2005 034 880.7 filed Jul. 26, 2005, both of the applications are incorporated by reference herein in their entirety.
FIELD OF INVENTION
The present invention relates to a method and a device for diagnosis of an exhaust gas cleaning system.
BACKGROUND OF THE INVENTION
According to current legislation and statutory regulations, a self-monitoring function (on-board diagnosis) which monitors adherence to the maximum permissible emissions of hydrocarbons, carbon monoxide and nitrogen oxides is specified for new vehicles with an internal combustion engine. In order to comply with the legal requirements, different diagnosis functions are generally integrated within the engine management system of the internal combustion engine. Special importance is attached in this context in particular to the diagnosis of catalytic converters present in the exhaust gas tract of the internal combustion engine.
Methods for the diagnosis of catalytic converters are currently in general use in which the oxygen storage capacity (OSC) of the catalytic converter is determined and used as a measure for the ability of the catalytic converter to convert hydrocarbons, carbon monoxide and nitrogen oxides. The core of OSC-based catalytic converter diagnosis is determining the ability of the catalytic converter to store oxygen. For this purpose a balance is typically kept of oxygen volumes which flow into or, as the case may be, flow out of the catalytic converter in a defined period of time. At the same time it must be ensured by means of suitable measures that the volume of oxygen already stored in the catalytic converter does not give rise to any errors when determining the OSC.
A common feature of all currently known methods for determining the OSC is that they require an exhaust gas probe upstream and an exhaust gas probe downstream of the catalytic converter that is to be diagnosed. If one of these exhaust gas probes is not present, it is not possible to diagnose the catalytic converter on the basis of the oxygen storage capacity. In particular for exhaust gas cleaning systems in a Y configuration, variants can occur in which exhaust gas probes are not provided upstream and downstream of all the catalytic converters which are present. With a first exhaust manifold and a second exhaust manifold, exhaust gas cleaning systems in a Y configuration have two exhaust manifolds, to which a first individual catalytic converter and a second individual catalytic converter are assigned respectively. Downstream of the individual catalytic converters the exhaust gas comes together in a common exhaust pipe. Further downstream the common exhaust pipe opens into a main catalytic converter.
In order to determine the oxygen storage capacity of all three catalytic converters of an exhaust gas cleaning system in Y configuration with the methods which are conventionally used, five exhaust gas probes are needed: one exhaust gas probe upstream of each of the individual catalytic converters and between each of the individual catalytic converters and the main catalytic converter, as well as downstream of the main catalytic converter. For reasons of cost it may be necessary to dispense with one exhaust gas probe between an individual catalytic converter and the main catalytic converter. The oxygen storage capacity of this individual catalytic converter cannot then be determined by means of the methods which are conventionally used.
SUMMARY OF INVENTION
The object of the invention is to provide a method and a device by means of which the diagnosis of an individual catalytic converter of an exhaust gas cleaning system in a Y configuration can be made possible, despite a lack of an exhaust gas probe between the individual catalytic converter and a main catalytic converter.
The object is achieved by the features of the independent claims. Advantageous embodiments of the invention are characterized in the dependent claims.
The invention is characterized by a method and a corresponding device for diagnosing an individual catalytic converter of an exhaust gas cleaning system in a Y configuration, despite the lack of an exhaust gas probe between the individual catalytic converter (referred to in the following text as the second individual catalytic converter) and a main catalytic converter, wherein the diagnosis is carried out on the basis of the signals from the exhaust gas probes associated with the exhaust gas cleaning system. With regard to the method, the oxygen storage capacity of the other individual catalytic converter present in the exhaust gas cleaning system (referred to in the following text as the first individual catalytic converter) is determined on the basis of the signals from two exhaust gas probes by means of the known method, whereby one exhaust gas probe is located upstream and another exhaust gas probe is located between the first individual catalytic converter and the main catalytic converter.
Furthermore, the sum of the oxygen storage capacities of the first individual catalytic converter and the main catalytic converter is determined on the basis of the signals of the exhaust gas probe upstream of the first individual catalytic converter and the signals of an exhaust gas probe downstream of the main catalytic converter. Moreover, the sum of the oxygen storage capacities of the second individual catalytic converter and the main catalytic converter are determined on the basis of the signals of an exhaust gas probe upstream of the second individual catalytic converter and the signals of the exhaust gas probe downstream of the main catalytic converter. The oxygen storage capacity of the second individual catalytic converter is determined on the basis of the oxygen storage capacity of the first individual catalytic converter, the sum of the oxygen storage capacities of the first individual catalytic converter and the main catalytic converter and the sum of the oxygen storage capacities of the second individual catalytic converter and the main catalytic converter. The diagnosis of the second individual catalytic converter is performed by means of the oxygen storage capacity.
The method has the advantage that a diagnosis of the second individual catalytic converter can take place despite a lack of exhaust gas probe between the second individual catalytic converter and the main catalytic converter. This means that the exhaust gas cleaning system can be implemented at low cost by dispensing with an exhaust gas probe. Furthermore, the method means that it is possible to determine the oxygen storage capacity of the second catalytic converter even if its oxygen storage capacity is very much less than that of the main catalytic converter.
In an advantageous embodiment of the invention, the oxygen storage capacity of the second individual catalytic converter is determined according to the following formula:
OSC2=OSC1+OSC2HK−OSC1HK,
where OSC 2 is the oxygen storage capacity of the second individual catalytic converter, OSC 1 the oxygen storage capacity of the first individual catalytic converter, OSC 2 HK the sum of the oxygen storage capacities of the second individual catalytic converter and the main catalytic converter, and OSC 1 HK is the sum of the oxygen storage capacities of the first individual catalytic converter and the main catalytic converter. In addition to a simple calculation of the oxygen storage capacity of the second individual catalytic converter, the forming of the difference between the terms OSC 2 HK and OSC 1 HK produces yet a further advantage. The forming of the difference reduces the influence of errors during the measuring of the signals of the exhaust gas probes and errors of the exhaust gas probes on the determination of the oxygen storage capacity. Offset errors of linear lambda probes, errors caused by the switching delay of binary lambda probes or errors when determining the volumetric air flow can be cited as possible errors in this connection.
In a further advantageous embodiment of the invention, the second individual catalytic converter is operated with a stoichiometric exhaust gas during the determination of OSC 1 HK(lambda=1.0). This ensures that no oxygen is carried into or out of the main catalytic converter via the second individual catalytic converter, which would lead to falsification of the determination of OCS 1 HK.
Alternatively, the determination of the oxygen storage capacity of the second individual catalytic converter can also be performed by means of a slightly modified method. For this alternative method, the oxygen storage capacity of the main catalytic converter is determined on the basis of the signals of the exhaust gas probe between the first individual catalytic converter and the main catalytic converter and the signals of the exhaust gas probe downstream of the main catalytic converter. Furthermore, the sum of the oxygen storage capacities of the second individual catalytic converter and the main catalytic converter is determined on the basis of the signals of the exhaust gas probe upstream of the second individual catalytic converter and the signals of the exhaust gas probe downstream of the main catalytic converter. The oxygen storage capacity of the second individual catalytic converter is determined on the basis of the oxygen storage capacity of the main catalytic converter and the sum of the oxygen storage capacities of the second individual catalytic converter and the main catalytic converter.
In an advantageous embodiment of this alternative method, the oxygen storage capacity of the second individual catalytic converter is determined according to the following formula:
OSC2=OSC2HK−OSCHK,
where OSC 2 is the oxygen storage capacity of the second catalytic converter, OSC 2 HK is the sum of the oxygen storage capacities of the second individual catalytic converter and the main catalytic converter, and OSCHK is the oxygen storage capacity of the main catalytic converter. This formula allows simple calculation of the oxygen storage capacity of the second individual catalytic converter. Furthermore, because of the forming of the difference, the influence of errors during the measurement of signals of the exhaust gas probes and errors of the exhaust gas probes on the determination of the oxygen storage capacity is diminished.
In a further advantageous embodiment of the invention, the first individual catalytic converter is operated with a stoichiometric exhaust gas during the determination of OSC 2 HK (lambda=1.0). This ensures that no oxygen is carried into or out of the main catalytic converter via the first individual catalytic converter, thus falsifying the determination of OCS 2 HK.
In a further advantageous embodiment of the invention, the individual oxygen storage capacities (OSC 1 , OSC 1 HK, OSC 2 HK, OSCHK) are determined by varying the lambda value of the exhaust gas in the corresponding catalytic converters by means of targeted measures in such a way that an oscillating waveform is produced around the value lambda=1.0.The oscillation parameters (curve shape, amplitude, cycle period) are selected in such a way that a considerably higher oxygen loading occurs as opposed to normal operation (oxygen volume which has to be alternately stored or discharged). From the waveform of the signals of the corresponding exhaust gas probe it must be possible to record a response which enables the respective oxygen storage capacity to be calculated.
In a further advantageous embodiment, the individual oxygen storage capacities (OSC 1 , OSC 1 HK, OSC 2 HK, OSCHK) are determined by varying the lambda value of the exhaust gas abruptly by means of suitable measures around the value lambda=1.0. In this embodiment the lambda stimulation is implemented by means of lambda jumps (e.g. from lambda=0.95 to lambda=1.05 and from lambda=1.05 to lambda=0.95). Furthermore, varying the parameters amplitude and stimulation period is usually dispensed with. The oxygen storage capacity of the catalytic converter is determined through keeping a balance of the oxygen volume carried into or out of the catalytic converter over the period from the start of the lambda jump through to the establishment of a response at the corresponding exhaust gas probe downstream of the catalytic converter.
In a further advantageous embodiment, the method is applied to an internal combustion engine which mainly operates in super-stoichiometric mode (lean operation). In this mode of operation large volumes of nitrogen oxides are generated, thus necessitating efficient cleaning of the exhaust gas. Efficient cleaning can be ensured by means of an exhaust gas cleaning system in a Y configuration.
In a further advantageous embodiment, the first and the second individual catalytic converters are implemented as three-way catalytic converters and the main catalytic converter is embodied in the form of a NOx storage catalytic converter. With this configuration, nitrogen oxides in the exhaust gas can be reduced in a particularly effective way.
In a further advantageous embodiment, the individual storage capacities (OSC 1 , OSC 1 HK, OSC 2 HK, OSCHK) are determined on the basis of the signals of the exhaust gas probes which are captured during a regeneration phase of the NOx storage catalytic converter. The lambda value of the exhaust gas is changed abruptly for the purpose of regenerating the NOx storage catalytic converter. These jumps can be used in order to determine the oxygen storage capacities. This means that the oxygen storage capacity can be determined without the additional emissions caused by the catalytic converter diagnosis and without additional fuel being consumed for the purpose of the determination.
In a further advantageous embodiment, the oxygen storage capacities OSC 1 HK and OSC 2 HK are determined at the end of a regeneration of the NOx storage catalytic converter. This eliminates the influence of the nitrogen oxides stored in the NOx storage catalytic converter on the determination of the oxygen storage capacities.
In a further advantageous embodiment, the lambda value of the exhaust gas flowing through the first individual catalytic converter is selected to be correspondingly lean (e.g. lambda>1.05) during the determination of OSC 1 HK so that the NOx storage catalytic converter is placed in a state in which to be able to again store the nitrogen oxides contained in the exhaust gas. This ensures that no additional nitrogen oxide emissions are produced as a result of determining OSC 1 HK.
In a further advantageous embodiment, the lambda value of the exhaust gas flowing through the second individual catalytic converter is selected to be correspondingly lean (e.g. lambda>1.05) during the determination of OSC 2 HK so that the NOx storage catalytic converter is placed in a state in which to be able again to store the nitrogen oxides contained in the exhaust gas. This ensures that no additional nitrogen oxide emissions are produced as a result of determining OSC 2 HK.
In a further advantageous embodiment, the first individual catalytic converter is operated with a slightly super-stoichiometric exhaust gas (e.g. 1.0<lambda<1.01) during the determination of OSC 2 HK. The result of this is that the first individual catalytic converter is slowly filled with oxygen. Filling must proceed slowly in order to ensure that no oxygen from the first individual catalytic converter falsifies the results during the determination of OSC 2 HK. Fulfillment of this requirement can be monitored by means of the exhaust gas probe which is positioned between the first individual catalytic converter and the NOx storage catalytic converter. When the determination of OSC 2 HK has been completed, the determination of OSC 1 can be concluded rapidly. The advantage of determining OSC 1 in accordance with this embodiment consists in a lessening of the influence of measuring errors of the exhaust gas probes due to dynamic processes, as the process runs more slowly as opposed to the determination of OSC 1 during a regeneration of the NOx storage catalytic converter.
In a further advantageous embodiment, the exhaust gas probes are implemented upstream of the first and second catalytic converter in the form of linear lambda exhaust gas probes. The exhaust gas probe between the first individual catalytic converter and the main catalytic converter is implemented in the form of a binary lambda exhaust gas probe. Furthermore, the exhaust gas probe downstream of the main catalytic converter is implemented in the form of a binary lambda exhaust gas probe or as a NOx exhaust gas probe with lambda signal output. This configuration makes possible efficient determination of the oxygen storage capacities.
BRIEF DESCRIPTION OF THE DRAWINGS
Exemplary embodiments of the invention are described in the following with reference to the schematic drawings, in which:
FIG. 1 shows an exhaust gas cleaning system of an internal combustion engine in a Y configuration and
FIG. 2 variations in the signals from exhaust gas probes over time in order to illustrate the method according to the invention.
DETAILED DESCRIPTION OF INVENTION
FIG. 1 shows an exhaust gas system in a Y configuration associated with an internal combustion engine 1 . The internal combustion engine 1 has two cylinder banks 2 , 3 . An exhaust manifold 5 is assigned to the cylinder bank 2 and an exhaust manifold 4 is assigned to the cylinder bank 3 for cleaning of the exhaust gas generated by the cylinder bank 2 , 3 respectively. Furthermore, the exhaust manifold 4 includes an individual catalytic converter 6 and the exhaust manifold 5 includes an individual catalytic converter 7 for cleaning of the exhaust gases generated in the respective cylinder banks 2 , 3 . Downstream, exhaust pipes 8 , 9 of the exhaust manifolds 4 , 5 converge into a common exhaust pipe 10 . The common exhaust pipe opens into a main catalytic converter 11 . The main catalytic converter 11 serves for removing pollutants from the exhaust gas which can be only inadequately removed with the individual catalytic converters 6 , 7 . For example, the main catalytic converter 11 can be implemented as a NOx storage catalytic converter 11 and the individual catalytic converters 6 , 7 can be implemented as three-way catalytic converters.
Furthermore, the exhaust gas cleaning system has an exhaust gas probe 12 upstream of a first individual catalytic converter 6 , an exhaust gas probe 13 upstream of a second individual catalytic converter 7 , an exhaust gas probe 14 between the first individual catalytic converter 6 and the main catalytic converter 11 and an exhaust gas probe 15 downstream of the main catalytic converter 11 . The exhaust gas probes 12 , 13 , 14 , 15 can be implemented for example as linear or binary lambda probes. The signals of the exhaust gas probes 12 , 13 , 14 , 15 are captured by an electronic computing unit 16 . On the basis of the signals it is possible to regulate the air-fuel mixture supplied to the internal combustion engine 1 , to regenerate individual catalytic converters or to determine the oxygen storage capacities of individual catalytic converters. No exhaust gas probe is present between the second individual catalytic converter 7 and the main catalytic converter 11 . Nevertheless, the method according to the invention allows the determination of the oxygen storage capacity of the second individual catalytic converter 7 .
In order to clarify the method according to the invention, FIG. 2 shows the variations in the signals of the exhaust gas probes 12 , 13 , 14 , 15 over time. In this example, the internal combustion engine 1 operates mainly in super-stoichiometric mode (lean operation). Accordingly, the main catalytic converter 11 is implemented in the form of a NOx storage catalytic converter and the individual catalytic converters 6 , 7 are implemented in the form of three-way catalytic converters. Furthermore, the exhaust gas probes 12 , 13 upstream of the two individual catalytic converters 6 , 7 are implemented in the form of linear lambda probes and the exhaust gas probe 14 between the first individual catalytic converter 6 and the NOx storage catalytic converter is implemented as a binary lambda probe. The exhaust gas probe 15 downstream of the NOx storage catalytic converter is implemented in the form of a binary lambda probe or as a NOx sensor with lambda signal output. The diagnosis of the exhaust gas cleaning system is carried out by means of two diagnostic cycles, with abrupt changes in the progression of the lambda value of the exhaust gas, caused by regeneration of the NOx storage catalytic converter, being used for the diagnosis within the individual diagnostic cycles. This results in the advantage that the diagnosis of the, exhaust gas cleaning system is carried out without additional emissions caused by the catalytic converter diagnosis, and that only a minimal amount of additional fuel is required for the diagnosis.
At the start of the first diagnostic cycle, (first regeneration of the NOx storage catalytic converter), the lambda value of the exhaust gas of both exhaust manifolds 4 , 5 is suddenly changed from lambda>1.5 to lambda≈0.8 at point in time t 1 . The sudden change reveals itself in the shape of the signals of the linear exhaust gas probes 12 , 13 upstream of the two individual catalytic converters 6 , 7 . At point in time t 1 , all the catalytic converters are saturated with oxygen because of the lean operation of the internal combustion engine 1 . The switchover to rich operation leads to the oxygen which is stored in the two individual catalytic converters 6 , 7 being discharged and used for oxidation of the hydrocarbons and carbon monoxides which are present in the exhaust gas. As soon as the oxygen stored in the individual catalytic converters 6 , 7 has been consumed, the rich exhaust gas flows through the two individual catalytic converters 6 , 7 without being influenced. This state is shown by the binary exhaust gas probe 14 between the first individual catalytic converter 6 and the NOx storage catalytic converter at point in time t 2 . The oxygen storage capacity of the first catalytic converter 6 can now be determined with the aid of an oxygen balance determination. It can be determined by means of the area shown in FIG. 2 which includes the signal of the exhaust gas probe 12 upstream of the first individual catalytic converter 6 between points in time t 1 and t 2 with the straight line parallel to the time axis through the point lambda=1.
After the oxygen in the individual catalytic converters 6 , 7 has been consumed, the rich exhaust reaches the NOx storage catalyst. Here, the stored oxygen and the stored nitrogen oxides are now released. The oxygen is again used directly for oxidation of the hydrocarbons and carbon monoxides contained in the exhaust gas. The stored nitrogen oxides are first reduced to nitrogen and oxygen. The oxygen which results is made use of again immediately for oxidation of the hydrocarbons and carbon monoxides. After all the oxygen stored in the catalytic converters has been consumed, the rich exhaust gas can no longer be further oxidized. This leads to what is termed the rich breakthrough, which is indicated by the lambda signal of the exhaust gas probe 15 downstream of the NOx storage catalytic converter at point in time t 3 . This point in time identifies the end of the first regeneration of the NOx storage catalytic converter.
Keeping an oxygen balance of the entire oxygen clearing process of all catalytic converters of the exhaust gas cleaning system yields a stored volume of oxygen. This stored oxygen volume is not, however, representative of the condition of the catalytic converter, since the stored volume of nitrogen oxides is also contained therein. For this reason the influence of the nitrogen oxides stored in the NOx storage catalytic converter has to be eliminated when determining OSC 1 HK and OSC 2 HK. Therefore OSC 1 HK and OSC 2 HK are determined at the end of a regeneration of the NOx storage catalytic converter. During the first diagnostic cycle, a first exhaust manifold 4 is operated with a stoichiometric exhaust gas (Lambda=1.0) as from point in time t 3 for the determination of OSC 2 HK. This operation can be carried out with a constant lambda or with an oscillating progression of the lambda value, the average of which results in lambda=1.0. FIG. 2 shows the operation with an oscillating progression of the lambda value and this operation can be seen in the shape of the signal of the linear exhaust gas probe 12 . A second exhaust manifold 5 is operated with lean exhaust gas, the lambda value of the exhaust gas having a defined value. Following this is a period of waiting while the second individual catalytic converter 7 and the NOx storage catalytic converter are completely filled with oxygen. The end of this process is indicated by means of the lambda signal of the exhaust gas probe 15 downstream of the NOx storage catalytic converter at point in time t 4 . OSC 2 HK is determined by means of an oxygen balance. OSC 2 HK can be determined by means of the area shown in FIG. 2 which includes the signal of the exhaust gas probe 13 upstream of the second catalytic converter 7 between points in time t 3 and t 4 with the straight line parallel to the time axis through point lambda=1.
The signals of the exhaust gas probes 12 , 13 , 14 , 15 during the subsequent regeneration of the NOx storage catalytic converter are used for the second diagnostic cycle. In this case the roles of the exhaust manifolds 4 , 5 are reversed, i.e. as from point in time t 5 , the second exhaust manifold 5 is operated with a stoichiometric exhaust gas (lambda=1.0). The first exhaust manifold 4 is operated with lean exhaust gas as from this point in time, the lambda value of the exhaust gas having a defined value. Following this is a period of waiting while the first individual catalytic converter 6 and the NOx storage catalytic converter are completely filled with oxygen. The end of this process is indicated by means of the lambda signal of the exhaust gas probe 15 downstream of the NOx storage catalytic converter at point in time t 6 . OSC 1 HK is determined by means of an oxygen balance determination. OSC 1 HK can be determined by means of the area shown in FIG. 2 which includes the signal of the exhaust gas probe 12 upstream of the first catalytic converter 6 between points in time t 5 and t 6 with the straight line parallel to the time axis through point lambda=1.
It is now possible to determine OSC 2 using the formula
OSC2=OSC1+OSC2HK−OSC1HK.
In selecting the lean lambda value for determining OSC 2 HK and OSC 1 HK it should be ensured that the lambda value of the exhaust gas is selected in such a way that the NOx storage catalytic converter is already able to store the nitrogen oxides contained in the exhaust again (e.g. lambda>1.05). In this means no additional nitrogen oxide emissions are produced during the determination of the oxygen storage capacities. | The invention is distinguished by a method and a corresponding device for diagnosis of an individual catalytic converter of an exhaust gas purification unit assigned to an internal combustion engine in the Y configuration, despite the lack of exhaust gas probe between the individual catalytic converter and a main catalytic converter. The diagnosis proceeds on the basis of signals from the exhaust gas probes belonging to the exhaust gas purification unit. On the basis of these signals, the oxygen storage capacity of the individual catalytic converter is determined despite the lack of exhaust gas probe between the individual catalytic converter and the main catalytic converter. | 8 |
DESCRIPTION
This invention relates to a process and to an apparatus for removing shrunk-on sleeves or all-round labels from vessels according to the precharacterising clause of claim 1 and to the precharacterising clause of claim 10, respectively.
Processes for removing shrunk-on sleeves or all-round labels surrounding vessels are already known in which a parting line is first produced substantially transverse to the circumferential direction of a shrunk-on sleeve or an all-round label. Attempts are then made to blow off the cut-through all-round label or the shrunk-on sleeve by fluid jets (compressed air, water jets) aligned substantially radially in relation to the vessel outer wall (EP 0 587 358 A1) or to remove them by suction from the vessel outer wall by means of suction devices. In this respect it has been shown in particular that the detachment of the labels or shrunk-on sleeves after producing the parting line creates difficulties.
Accordingly, the underlying object of the present invention is to provide a process and an apparatus which permit improved detachment of the labels or shrunk-on sleeves.
This object is achieved with respect to the process by the characterising features of claim 1 and is achieved with respect to the apparatus by the characterising features of claim 10.
The production of a parting line in the covering material (all-round label, shrunk-on sleeve) can be effected in the known manner, e.g. by means of a cutter blade or a high-pressure water jet, for which purpose the vessels are preferably held clamped axially between their top and their bottom face on a conveyor device, generally on a continuously drivable turntable. After the parting line is produced, the vessels, e.g. drinks bottles made of plastics (PET) are held as far as possible in the region near their mouths with their bases free, so that the covering material is removed by fluid jets which are aligned obliquely from above, substantially axially in relation to the vessel outer wall, and which impinge at high pressure on the vessel outer wall, preferably above the top edge of the covering material.
Because the vessels are suspended with their bases free, the detached covering material can be conveyed away without problems and in a trouble-free manner.
The process and the apparatus which is suitable therefor can be used particularly advantageously in beverage filling lines for returnable bottles, particularly plastics bottles (PET), which have a neck collar below their mouths. The neck collar facilitates ease of handling of the bottles during the detachment of the covering material.
The fluid jets can be produced by compressed air and/or water. When water or another suitable liquid is used, a closed circuit can be produced by capturing the floated-off covering material and the liquid underneath the bottles, separating the covering material and feeding it to a press for compaction, for example, and feeding the liquid collected in a container to the nozzles for re-use, by means of a pump. Prior purification of the liquid by filtration or other measures is optionally effected. Moreover, cleaning substances may be admixed with the liquid in order also to effect a preliminary cleaning of the outside of the bottles during the removal of the covering material.
According to a further embodiment, it is particularly advantageous if the vessels are rotated about their vertical axes during the impingement of the fluid jets on their outsides, so that substantially almost the whole periphery of a bottle is impinged upon by fluid, even if fixed jet nozzles are used. In this respect it is advantageous if a plurality of jet nozzles are disposed in succession along both sides of the path of movement of the bottles, preferably with decreasing height as seen in the direction of conveying. It may also be advantageous to cause the individual fluid jets to impinge on the bottle walls at different angles, and preferably to fasten the jet nozzles so that they are adjustable.
Other advantageous forms of the process and of the apparatus are given in the subsidiary claims.
A preferred embodiment is described below with reference to the Figures, where:
FIG. 1 is a schematic plan view of a machine for removing covering material;
FIG. 2 is a vertical partial section along section line II--II through the machine illustrated in FIG. 1;
FIG. 3 is a vertical section along line III--III through the machine illustrated in FIG. 1;
FIG. 4 is an enlarged sectional illustration of the bottle holding device depicted in FIG. 3; and
FIG. 5 is a plan view of the mounting system for the jet nozzles depicted in FIGS. 3 and 4.
The machine for removing covering material which is schematically illustrated in FIG. 1 comprises a table plate 1, on which a continuously drivable turntable 2, which has an associated input star wheel 7 and an output star wheel 8, is rotatably mounted. An input conveyor belt 5 with a one-piece screw 6 is associated with the input star wheel 7 for feeding the bottles 4 to be processed. The one-piece screw is driven synchronously in a positionally correct manner with respect to the turntable 2, as are the feeder belt 5, the input star wheel 7 and the output star wheel 8. A curved guide sector 8 is situated between the input star wheel 7 and the output star wheel 9. Two curved guide rails 40 and 41, which together form a guide slot for guiding the tops of the bottles through, are disposed fixed above the output star wheel 9. The inside width of the guide slot is slightly greater than the outside diameter of the top of a bottle. A straight friction strip 42, which is held fixed, adjoins the guide rail 40, and extends as far as a discharge conveyor 50 with an associated discharge conveyor screw 51. A chain 45 which can be driven synchronously with the output star wheel 9 via chain wheels 43 and 44 is disposed opposite and at a distance from the friction rail, and carries rollers 46, which are each freely rotatably mounted in pairs with a uniform spacing.
A plurality of jet nozzles 60 is disposed in succession along both sides of the rectilinear conveying path of the bottles in the region between the output star wheel 9 and the discharge conveyor belt 50. A catchment hopper 70 is disposed in the region of the jet nozzles 60, underneath the bottles 4, which are suspended, with their bases free, between the output star wheel 9 and the discharge conveyor belt 50 (FIG. 3).
The turntable 2 (FIG. 2) carries a plurality of uniformly spaced bottle plates 3, which are disposed on a reference circle. These bottle plates 3 can be rotatably mounted on the bottle table 2, and their rotational position can be manipulated by an associated drive 20 (servomotor, cam control system or the like). As can be seen from FIG. 2, a carrier disc 11, which is not shown in FIG. 1, is disposed at a distance above the turntable 2 and parallel thereto, and is attached rotationally fixed to a central shaft 12 driven in rotation, as is the turntable 2. Raisable and lowerable centring cones or cups 19, which are aligned with the bottle plates 3, are disposed at the periphery of the carrier disc 11. Each centring cone 19 is freely rotatably mounted at the lower end of a guide rod 17, which is mounted so that it can slide up and down at the periphery of the carrier disc 11 and is equipped with a cam roller 18 at its upper end. This cam roller 18 engages with positive fit in a radial cam 13 which is held stationary by means of a holding pillar 16 and an extension arm 15.
Two guide rods 21, which are aligned parallel to the vertical axis 23 of the bottle 4, are fixed between the turntable 2 and the carrier disc 11 disposed above the latter, radially inwardly of the path of circulation of the bottle 4, which is held axially clamped between its mouth and its bottom face. A support body 22 is displaceably mounted on these guide rods 21. The support body has a cam roller 25 on its side facing radially inwards towards the central shaft 12, which cam roller engages with positive fit in a radial cam 26 which is held stationary. The support body 22 is provided with a slot on its side facing radially outwards towards the bottle 4, in which slot a horizontal bearing axis 27 is disposed on which a cutter 31 is swivel-mounted. The cutter is permanently acted upon by a pressure spring 28 towards the outer curved surface of the bottle 4. The cutter 31 has a cutting edge 24 which points radially outwards away from the curved surface of the bottle 4. The arrangement of the cutter 31 is selected so that the point of the cutter is pressed against the curved surface by the pressure spring 28, the radial cam 26 being constructed so that the point of the cutter 31 is placed above the top edge of the all-round label or the shrunk-on sleeve 30 adhering to the bottle 4 and is subsequently moved downwards in the cutting direction S. During this downward movement the point of the cutter penetrates between the curved surface of the bottle 4 and the back of the label 30. The label is cut through from back to front by the outwardly oriented cutting edge 24. The axial parting line which is produced in the label 30 runs substantially parallel to the vertical axis 23 of the bottle 4. Instead of the cam roller 25 and radial cam 26 illustrated, the up and down movement of the cutter 31 may also be produced by any other suitable operating device, e.g. a controlled pneumatic cylinder.
Detachment of the labels or shrunk-on sleeves 30, which have already been cut through transverse to their circumferential direction, is effected in the detachment station which is illustrated in FIG. 3 as seen in the direction of conveying. The bottles 4 are held radially at their top regions between the fixed friction rail 42, which is provided with a continuous longitudinal channel, and an opposing pair of rollers 46. The freely rotatable rollers 46 have a groove extending over their entire circumference which serves to receive the neck collar 14 situated underneath the mouth of the bottle 4. This neck collar 14 is also seated in the friction rail 42 by means of the aforementioned channel. Below the neck collar 14, the entire curved surface of the bottle 4, which is suspended with its base free, is accessible to the fluid jets 80 which are discharged obliquely from above by the jet nozzles 60. The fluid jets 80 impinge at an acute angle on the curved surface of the freely suspended bottle 4, preferably above the top edge of the cut-through label 30, so that at least part of the fluid can penetrate between the vessel outer wall and the back of the label, due to which the label 30 is rapidly and reliably detached. Pressurised water jets are preferably used as the fluid jets 80.
The water flowing downwards from the bottle outer wall and the labels 30 detached from the bottle 4 are collected by a catchment hopper 70 disposed under the bottles 4, which hopper is open at the bottom, and are delivered on to a label extraction device 71 disposed underneath. The label extraction device 71 consists of a screen belt 74 or the like, which is guided over two drivable rollers 72 and 73 and which is permeable to water. Water flowing off from the catchment hopper 70 can thereby drip off unimpededly into a collecting vessel 76, which is open at the top and which is situated under the screen belt 74, whilst the separated labels 30 are discharged laterally into the hopper of a label press 75. The water collected in the container 76 is withdrawn by a pump 77 and fed to the jet nozzles 60 again.
The construction of the chain 45 for conveying the bottles from the output star wheel 9 to the discharge conveyor 50, which was merely indicated schematically in FIG. 1, can be seen in detail from the vertical section illustrated in FIG. 4. A support 91, which comprises multiple bends and which extends from the deflection chain wheel 44 as far as the drive chain wheel 43 (FIG. 1) is fixed to a plurality of supporting pillars 90 disposed in succession along one side of the conveying path of the bottles. A plurality of transverse arms 93 is disposed at a distance above the path of the mouths of the bottles. The transverse arms are disposed in succession on the top face of the support and serve for the fixed mounting of the friction rail 42 and of a sliding rail 94 disposed above the latter. A second, opposing sliding rail 94 which extends horizontally is associated with this sliding rail 94 at the same height on the support 91. Stirrups 48 bent into a U-shape are fixed with a uniform spacing to the roller chain 45, which circulates in a horizontal plane. Each of the stirrups carries two freely rotatable rollers 46 on its lower limb for receiving the neck collar 14 of a bottle 4, and the upper limb of the stirrup slides on the top face of the sliding rails 94. The lower limb has a recess, which is not illustrated, between the rollers 46 for the top of the bottle. So that a bottle mouth which is rotatably clamped between a pair of rollers 46 and the friction rail 42 is guided accurately and reliably, a supporting rail 47; 49 for the rollers 46 and the roller chain 45, respectively, is fixed to the support 91.
A plurality of vertical round rods 81, which are each disposed side by side in pairs and are displaced in succession in the direction of conveying, is rigidly fixed to the support 91 for mounting the jet nozzles 60 (FIG. 5). A horizontally aligned transverse rod 82 is adjustably mounted on each of these pairs of rods with the aid of clamping pieces 85. Longitudinal rods 83, which extend in the direction of conveying F and to which the jet nozzles 60 are fixed by means of clamping pieces 87, are mounted on these transverse rods 82, again by means of clamping pieces 86 (FIG. 5). The said clamping pieces each have two receiver bores which cross each other at right angles on offset planes, by means of which both the angle of the jet nozzles 60 to the bottle outer wall and the vertical position of the jet nozzles 60 can be continuously adjusted. In addition, the lateral distance between two opposing jet nozzles 60 can also be adjusted continuously by the clamping pieces 86 to match the width of the bottle. The jet nozzles 60 can be adjusted so that the fluid jets 80 emerging from jet nozzles 60 which are disposed in succession as seen in the direction of conveying impinge on the bottle outer wall at decreasing heights and/or at different angles. It can also been seen from FIG. 5 in combination with FIG. 4 that window-like apertures 92 are present in the longitudinal support 91 through which the nozzles 60 are passed.
The operating sequence for a bottle passing through the machine is described below by way of example.
A bottle 4 provided with an overlapping all-round label 30 which is partially adhesively bonded to its outer wall is conveyed from the feeder conveyor 5 to the one-piece screw 6, carried by the latter on to the machine portion and introduced into a receiver pocket of the star wheel 7. In cooperation with the curved guide sector 8, the star wheel 7 conveys the bottle 4 on to a bottle plate 3 of the turntable 2, whereupon the bottle 4 is simultaneously clamped axially between its mouth and bottom face by the centring cone 19 being lowered. The spring-loaded cutter 31 seated against the outside of the bottle 4 is then moved axially on the bottle wall from the top edge of the label to the bottom edge of the label, whereupon the cutter point penetrates between the outside of the bottle and the back of the label and the label 30 is cut through from the back of the label by the cutting edge 24, which points away from the outside of the bottle. The cutter 31 is then moved back upwards again into its original starting position for the next cutting operation. As soon as the bottle 4 with the label 30 which has been cut through transverse to its circumferential direction enters the output star wheel 9, the centring cone 19 is raised from the bottle mouth, due to which the axial clamping operation is terminated. The top of the bottle 4 is introduced into the gap between the guide rails 40 and 41 by the output star wheel 9, whereupon the guide rails engage below the neck collar 14 of the bottle and slightly raise the bottle during its forward movement in the output star wheel 9. The neck collar 14 of the bottle 4 is accurately introduced into the channel of the friction rail 42 and the groove in the rollers 46 by means of the guide rails 40 and 41, whilst at the same time a pair of rollers 46 is swung round past the friction rail 42 by the deflection wheel 44 at the end of the guide rail 41. In this operation the neck collar 14 of the bottle 4 is radially rotatably clamped at three points on its circumference. The bottle 4 is rolled, rotating anti-clockwise, along the friction rail 42 due to the forward movement of the chain 45 in the direction of conveying F.
Compressed air is blown obliquely from above by the first pair of jet nozzles 60, at an acute angle on to the top edge of the all-round label which has already been cut through, in order to create a gap between the label and the bottle outer wall. Water under high pressure is discharged by the jet nozzles 60 which follow in the direction of conveying F. The water likewise impinges obliquely from above on the bottle wall and detaches the label from the bottle 4, which is suspended at its neck collar 14 with its base free. The detached label 30 and the water which runs off the bottle are fed by the catchment hopper 70 to the label extraction device disposed 71 underneath, and the water is introduced into the collecting vessel 76 (FIG. 3). The bottle 4, which is now free from its label, is introduced into the conveyor screw 51, which is driven synchronously with the chain 45, and is held and prevented from falling over by the conveyor screw whilst the neck collar 14 is released at the end of the friction rail 42. The bottle, which is now standing with its bottom face on the discharge conveyor belt 50, is subsequently conveyed away, e.g. to a bottle washing machine. | The invention relates to a process and a device for removing shrinking casings or encircling labels from containers, particularly bottles, glasses, cans, or the like, in which, first of all, a separating line which proceeds essentially transversely to the direction of circumference is produced and the shrinking casing or the encircling label is then removed by means of a fluid stream which is directed against the container. During the removal of an encircling label or of a shrinking casing which has been cut through, the containers are preferably held, in a bottom-free manner, near the area of the head, and at least one fluid stream is directed, in an angular manner, from above, essentially axially to the wall of the container, against the container, and preferably above the upper edge of the shrinking casing or of the encircling label. | 8 |
STATEMENT REGARDING PRIOR DISCLOSURES BY THE INVENTOR OR A JOINT INVENTOR
[0001] Various aspects of the present invention have been disclosed by an inventor or a joint inventor in the product Trusteer Apex v1307, made publically available on Apr. 23, 2014. This disclosure is submitted under 35 U.S.C. 102(b)( 1 )(A).
FIELD OF THE INVENTION
[0002] The present invention relates generally to computer security, and more particularly, to detecting “heap spraying” on a computer.
BACKGROUND OF THE INVENTION
[0003] Many computer operating systems use what is called heap memory to store data used by software applications during their execution. The essential requirement of memory management is to provide ways to dynamically allocate portions of memory to programs at their request, and free it for reuse when no longer needed. The task of fulfilling an allocation request consists of locating a block of unused memory of sufficient size. Memory requests are satisfied by allocating portions from a large pool of memory called the heap (e.g., heap memory) or free store. At any given time, some parts of the heap memory are in use, while some are “free” (unused) and thus available for future allocations.
SUMMARY
[0004] In one aspect of the present invention a method is provided for detecting heap spraying on a computer, the method includes detecting, by one or more processors, a plurality of requests to allocate portions of heap memory. The method further includes measuring, by one or more processors, the plurality of requests to determine a value of a characteristic of the plurality of requests. The method further includes identifying, by one or more processors, an activity consistent with heap spraying by determining that the value of the characteristic is consistent with a benchmark value of the characteristic, wherein the benchmark value of the characteristic is associated with heap spraying. The method further includes performing, by one or more processors, a computer-security-related remediation action responsive to determining that the value of the characteristic is consistent with the benchmark value of the characteristic.
[0005] In other aspects of the invention systems and computer program products embodying the invention are provided.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0006] Aspects of the present invention will be understood and appreciated more fully from the following detailed description taken in conjunction with the appended drawings in which:
[0007] FIG. 1 is a simplified conceptual illustration of a system for detecting heap spraying on a computer, constructed and operative in accordance with an embodiment of the present invention;
[0008] FIG. 2 is a simplified flowchart illustration of an exemplary method of operation of the system of FIG. 1 , operative in accordance with an embodiment of the present invention; and
[0009] FIG. 3 is a simplified block diagram illustration of an exemplary hardware implementation of a computing system, constructed and operative in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION
[0010] Embodiments of the present invention recognize that in order to take advantage of certain computer security vulnerabilities, designers of malicious software applications have developed a method known as “heap spraying” whereby data that includes malicious instructions are stored in a computer's heap memory to facilitate a later attack. In a typical heap spraying operation, multiple copies of such data are stored in heap memory to increase the likelihood that program execution flow will encounter one of the copies of the data and execute the instructions. Embodiments of the present invention allow for detecting heap spraying on a computer. Implementation of embodiments of the invention may take a variety forms, and exemplary implementation details are discussed subsequently with reference to the Figures.
[0011] The present invention may be a system, a method, and/or a computer program product. The computer program product may include a computer readable storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out aspects of the present invention.
[0012] The computer readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device. The computer readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of the computer readable storage medium includes the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon, and any suitable combination of the foregoing. A computer readable storage medium, as used herein, is not to be construed as being transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire.
[0013] Computer readable program instructions described herein can be downloaded to respective computing/processing devices from a computer readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a local area network, a wide area network and/or a wireless network. The network may comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. A network adapter card or network interface in each computing/processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium within the respective computing/processing device.
[0014] Computer readable program instructions for carrying out operations of the present invention may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C++ or the like, and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The computer readable program instructions may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). In some embodiments, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) may execute the computer readable program instructions by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects of the present invention.
[0015] Aspects of the present invention are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer readable program instructions.
[0016] These computer readable program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer readable program instructions may also be stored in a computer readable storage medium that can direct a computer, a programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer readable storage medium having instructions stored therein comprises an article of manufacture including instructions which implement aspects of the function/act specified in the flowchart and/or block diagram block or blocks.
[0017] The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer implemented process, such that the instructions which execute on the computer, other programmable apparatus, or other device implement the functions/acts specified in the flowchart and/or block diagram block or blocks.
[0018] The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts or carry out combinations of special purpose hardware and computer instructions.
[0019] Reference is now made to FIG. 1 which is a simplified conceptual illustration of a system for detecting heap spraying on a computer, constructed and operative in accordance with an embodiment of the present invention. In the system of FIG. 1 , an allocations monitor 100 is configured to detect requests to allocate portions of a heap memory 102 , memory within a computer memory of a computer 104 , where each of the allocation requests is a request to allocate a portion of heap memory 102 , typically for the purpose of storing an allocation data payload in the requested allocation portion. Allocations monitor 100 is preferably configured to detect such allocation requests, such as may be made by a computer software application during its execution by a computer, by intercepting calls to low-level memory allocation functions, such as to VirtualAllocEx and VirtualAlloc on computers running the MICROSOFT WINDOWS™ operating system, although the invention is applicable to other operating systems that are vulnerable to heap spraying. Optionally, allocations monitor 100 is configured to prevent such calls from being serviced by their called memory allocation functions. Allocations monitor 100 is also preferably configured to store each detected allocation request in a data structure or data file, together with an identification of the requesting process and a timestamp indicating the time that the allocation request was made. Allocations monitor 100 is also preferably configured to remove any such stored allocation requests where a deallocation request is detected that corresponds to a stored allocation request.
[0020] The system of FIG. 1 also includes an allocations analyzer 106 configured to periodically measure the detected allocation requests made by a given process, such as after detecting a predefined number of allocation requests, such as 1,000 allocation requests, to determine a value of one or more predefined characteristics of the allocation requests. Allocations analyzer 106 is preferably configured to perform the measurements on one or more groups of detected allocations requests, where a group of allocation requests is defined as those allocation requests that belong to the same time window of a predefined duration, such as 780 milliseconds, and preferably where the number of detected allocations request that belong to a group meets or exceeds a minimum, such as 300. In various embodiments, which may be employed individually or in any combinations thereof, allocations analyzer 106 is configured to:
measure the detected allocation requests in a group to determine the number of the allocation requests that request memory allocations of the same size; specify multiple byte positions within an allocation data payload, such as the first eight bytes of an allocation data payload, and measure the detected allocation requests in a group to determine the number of the allocation data payloads that have the same bytes at the same specified byte positions; measure the detected allocation requests in a group to determine the number of the allocation requests that are requests for allocations on executable pages within heap memory 102 .
[0024] Allocations analyzer 106 is also configured to determine whether the value of any of the characteristics described hereinabove is consistent with a predefined benchmark value of the characteristic that is associated with heap spraying, where this determination represents an identification of activity that is consistent with heap spraying. Thus, for example, any of the following benchmark values may be used to identify activity that is consistent with heap spraying when:
a predefined percentage, such as 90% or more, of the allocation data payloads in a group of allocation requests are of the same size; a predefined percentage, such as 90% or more, of the allocation data payloads in a group of allocation requests have the same bytes at the same specified byte positions; a predefined percentage, such as 90% or more, of the allocation requests in a group of allocation requests are requests for allocations on executable pages within heap memory 102 .
[0028] Allocations analyzer 106 is preferably configured to release to their called memory allocation functions any intercepted allocation requests that are not determined to be associated with activity that is consistent with heap spraying.
[0029] The system of FIG. 1 also includes a security manager 108 configured to perform one or more predefined computer-security-related remediation actions in response to the identification of activity that is consistent with heap spraying as described hereinabove. For example, for any group of allocation requests regarding which activity that is consistent with heap spraying is detected as described hereinabove, the remediation actions may include any of:
replacing their corresponding allocation data payloads with benign instructions (e.g., NOPs); terminating any process that is the source of any of the allocation requests; providing a computer-security-related notification reporting the activity, such as to a user or administrator of computer 104 .
[0033] Any of the elements shown in FIG. 1 are preferably implemented by one or more computers, such as by computer 104 , in computer hardware and/or in computer software embodied in a computer readable storage medium in accordance with conventional techniques.
[0034] Reference is now made to FIG. 2 which is a simplified flowchart illustration of an exemplary method of operation of the system of FIG. 1 , operative in accordance with an embodiment of the present invention. In the method of FIG. 2 , requests to allocate portions of a heap memory are detected (step 200 ). A group of allocation requests made by a given process in a given time window is measured to determine a value of one or more predefined characteristics of the allocation requests (step 202 ). If the value of any of the characteristics is consistent with a predefined benchmark value of the characteristic that is associated with heap spraying (step 204 ), then one or more predefined computer-security-related remediation actions are performed (step 206 ), which may include any of: replacing the allocation data payloads that correspond to the allocation requests with benign instructions (e.g., NOPs) or otherwise preventing execution of instructions in such data; terminating any process that is the source of any of the allocation requests; and providing a computer-security-related notification reporting that activity that is consistent with heap spraying has been detected.
[0035] Referring now to FIG. 3 , block diagram 300 illustrates an exemplary hardware implementation of a computing system in accordance with which one or more components/methodologies of the invention (e.g., components/methodologies described in the context of FIGS. 1-2 ) may be implemented, according to an embodiment of the present invention.
[0036] As shown, the techniques for controlling access to at least one resource may be implemented in accordance with a processor 310 , a memory 312 , I/O devices 314 , and a network interface 316 , coupled via a computer bus 318 or alternate connection arrangement.
[0037] It is to be appreciated that the term “processor” as used herein is intended to include any processing device, such as, for example, one that includes a CPU (central processing unit) and/or other processing circuitry. It is also to be understood that the term “processor” may refer to more than one processing device and that various elements associated with a processing device may be shared by other processing devices.
[0038] The term “memory” as used herein is intended to include memory associated with a processor or CPU, such as, for example, RAM, ROM, a fixed memory device (e.g., hard drive), a removable memory device (e.g., diskette), flash memory, etc. Such memory may be considered a computer readable storage medium.
[0039] In addition, the phrase “input/output devices” or “I/O devices” as used herein is intended to include, for example, one or more input devices (e.g., keyboard, mouse, scanner, etc.) for entering data to the processing unit, and/or one or more output devices (e.g., speaker, display, printer, etc.) for presenting results associated with the processing unit.
[0040] The descriptions of the various embodiments of the invention have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein. | Detecting heap spraying on a computer by determining that values of characteristics of a plurality of requests to allocate portions of heap memory are consistent with benchmark values of the characteristics, wherein the benchmark values of the characteristics are associated with heap spraying; and performing a computer-security-related remediation action responsive to determining that the values of the characteristics are consistent with the benchmark values of the characteristics. | 6 |
CROSS REFERENCE TO PENDING APPLICATIONS
This application includes material which overlaps material in pending U.S. patent application Ser. No. 07/499,114, filed Mar. 26, 1990, entitled "METHOD AND APPARATUS FOR DESCRIBING DATA TO BE EXCHANGED BETWEEN PROCESSES", inventors: Richard Demers, et al.; and U.S. patent application Ser. No. 07/500,031, filed Mar. 27, 1990, entitled "METHOD AND APPARATUS MINIMIZING DATA CONVERSIONS WHEN SHARING DATA BETWEEN PROCESSES", inventors: John G. Adair, et al.
BACKGROUND OF THE INVENTION
1. Technical Field
This invention addresses the problem of accessing a remote data repository, hereafter called a database management system (or DBMS), from an application program which is executing in a different computer than the DBMS.
2. Description of the Prior Art
Data repositories, or DBMSs, store information which can be used in many ways to manage, control, analyze, model, track, and document a wide variety of real work activities in business, commerce, science, and government. The information stored in DBMSs can be shared by various application programs which exploit the information for specific purposes. Because it is very difficult to maintain the same information in different DBMSs on different computers, it is important that application programs be able to access and manipulate needed information wherever it resides.
However, application programs must not only access and manipulate information in DBMSs, but also interact with humans via computer displays and keyboards. This interaction is greatly facilitated if the application program can execute on a computer which is physically near to the human. It is also sometimes the case that an application program developed and adapted to a specific computer environment defined by language, operating system, or computer may need to exploit data in, or the special features of, a DBMS which is adapted to (and runs on) a different computer environment. Therefore, it would be useful for application programs to be able to access and manipulate information in a DBMS which is located at a different computer than the computer of the application program.
Another aspect of maintenance of information in DBMSs is that there are many differently implemented DBMSs whose database commands are specialized to particular computing environments or data models. An important class of differently implemented DBMSs are those known as relation database systems. Within this class are those DBMSs whose database command language is known as SQL. C. J. Date in his book entitled "AN INTRODUCTION TO DATABASE SYSTEMS", Vol. 1, Addison-Wesley (4th Edition, 1986), describes in Chapter 2 a relational database system which is based on the SQL database command language. However, even within this restricted class of DBMSs, there are differences in the SQL commands which different implementations can accept and process. These differences in the SLQ database command language reflect the different operating environments of different implementation as well as differences in the language functions supported.
Application programs which exploit DBMSs supporting the SQL database command language are written in any one of several different programming languages. SQL database commands to access the DBMSs data are embedded in the programs of the applications. Application programs are prepared for execution in several steps. First a component of a Application Access Agent called the SQL Preprocessor examines the text of the application program and replaces embedded SQL database commands with calls to another component of the Application Access Agent called the Database Interface Functions. These Database Interface Functions mediate the actual interactions with the DBMSs to effect the execution of the SQL database commands. Next, the modified application program is processed by a language compiler which translates it into a machine dependent sequence of computer instructions. Finally, the translated application program is combined (or linked) with the Database Interface Functions to produce a module which can be invoked and executed in a specific computing environment.
In addition to replacing the SQL database commands embedded in an application program with calls to Database Interface Functions, some SQL Preprocessor systems and SQL DBMSs support the ability to analyze and prepare SQL database commands for execution well in advance of the need to perform the commands during execution of the linked application program. This preparation for database command execution, known as binding, significantly improves application program performance. This is because analysis of SQL database commands generally entails relatively costly I/O operations to compare the names of database objects (e.g., tables, columns, etc.) found in the commands to the names of objects present in the particular DBMS. In addition, for many SQL database commands, the determination of the best sequence of database steps necessary to perform the command entails consideration of a, possibly, large number of alternative sequences. Choosing the best sequence of steps is known as optimization. Once analysis and optimization have been completed, the DBMS can retain the result and use it whenever execution of the corresponding SQL database command is required.
The problem addressed by this invention is the provision of a mechanism and procedure by which application programs executing on one computer can exploit the full services of a DBMS running on a different computer with a, possibly, different computer environment. The invention specifically addresses exploitation of evolving and idiosyncratic features of the database command language of different implementations of the remote DBMSs. This tolerance of database command idiosyncrasies is achieved using a single embodiment (implementation) of the Application Access Agent programs, coupled via a communication protocol to the DBMSs in remote computers. The invention also achieves enhanced performance by supporting binding of database commands in advance of execution of the application program.
Alternative mechanisms addressing these goals include:
1. a (local) DBMS at the application program computer which is capable of interacting with other, remote DBMSs to perform database commands at those DBMSs (i.e., a distributed database system);
2. remote execution of the database calls which could have been made to a local DBMS implementation using a Remote Procedure Call (RPC) mechanism;
3. a program on the application program computer which accepts, analyses, and optimizes database commands and sends (communicates) the resulting sequence of database steps to the remote DBMS for immediate or deferred execution;
4. communicating the database commands of the application program to a program (or device) at the remote computer of the DBMS which issues the database commands to its (now local) DBMS on behalf of the (now remote) application program; and
5. the Remote Database Access (RDA) communication protocol under consideration by national and international standards bodies.
The first alternative above requires advanced database function which is not available in most DBMS implementations. In addition, it requires that such a DBMS be present at the application program computer. This might entail significant cost for licenses, maintenance, and resources (CPU and storage).
Because database call interfaces are usually specific to a DBMS implementation and its computing environment, the second alternative above would require special support at the application program computer for each differently implemented remote DBMS. This multiplicity of support for specific DBMS call interfaces is costly to develop and must be extended whenever new remote DBMS implementations become available.
The third alternative above is extremely sensitive both to the kinds of database steps used at the remote DBMS and to the database command language features and functions supported by the program at the application program which computes the needed steps. Furthermore, functional enhancements to the database command language of the remote DBMS must be matched by similar enhancements to the Application Access Agent.
The fourth alternative above cannot analyze and prepare database commands prior to execution because the database commands of the application program are not presented to the remote DBMS prior to the execution of the application program on the application program's computer.
The fifth alternative above (RDA), also does not support analysis and processing of database commands prior to the execution of the application program which invokes the execution of the database commands. This leads to (possibly) significant performance penalties and does not allow amortization of the cost of analyzing and optimizing database commands over multiple executions of the application program.
SUMMARY OF THE INVENTION
This invention operates in an environment consisting of a multiplicity of computer systems connected by a communication facility. Some of the computing systems are designated application program computers while the remaining computing systems are designated as DBMS computers. Both the application program computers and the DBMS computers may vary in their implementation and computing environments. The communication mechanism is operated according to a communication protocol agreed upon by the application program and DBMS computers. In this invention, the application program computers are physically separate from the DBMS computer; therefore, from the perspective of an application computer, a DBMS computer is a "remote" data site.
According to the invention, an application program which exploits a DBMS supporting a database command language can be written in any one of several different programming languages. Database commands to access the DBMS data are embedded in the program of the application. A Application Access Agent prepares the application program for execution in several steps and supports execution with full exploitation of DBMS data and facilities.
First, a component of the Application Access Agent called the Preprocessor examines the text of the application program and replaced embedded database commands with calls to another component of the Application Access Agent called the Database Interface Functions. This component mediates the actual interactions with the DBMS to effect the execution of the database commands. Next, the modified application program is processed by a language compiler which translates it into a machine-dependent sequence of computer instructions. The translated application program is combined or linked with the Database Interface Functions to produce a module which can be invoked and executed in a specific computing environment.
The embedded database commands extracted from the application program are assembled while the application program is being manipulated by the Preprocessor. The extracted database commands are analyzed and prepared for execution during preprocessing and are assembled. A Bind program component of the Application Access Agent interacts with a remote DBMS to bind the database commands from the application program to a named DBMS which retains the database commands for execution in response to execution of the application program.
Last, the Database Interface Function component of the Application Access Agent receives the calls in the application program which replace the database command. When a call is made from the application program, the Database Interface Function component notifies the DBMS of the called command, and the DBMS executes the command, sending the result back to the Database Interface Function. The received results are passed to the application program immediately or in response to subsequent requests from the application program.
This invention solves the problem of exploiting the facilities of a remote DBMS from a different application program computer by defining the necessary elements of a protocol for:
1. causing database commands to be bound (analyzed, optimized, and retained) at a remote DBMS computer; and
2. initiating execution of retained commands at the remote DBMS computer.
The goal of support for idiosyncratic versions of the database command language is achieved by limiting the degree to which the Application Access Agent programs at the application program computer must analyze and understand the meaning of database commands to the minimum necessary to transform application programs to properly call for the execution of their database commands. Additionally, the protocol for binding database commands at a remote DBMS computer is adapted so as to be insensitive to idiosyncrasies of the database command language syntax and semantics of the particular remote DBMS implementation.
Another significant feature of this invention is the extraction of Host Variables from the database language command prior to their being bound at the remote DBMS. The language-specific variables are replaced with markers which include information as to the type and size of the Host Variable. This isolates database language differences resulting from language dialects to the DBMS site. This enables the Application Access Agent to talk to all possible DBMSs the same way, independent of the DBMS type.
Other features and advantages of this 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
FIG. 1 is a block diagram showing the primary complement of elements which form the invention in combination with other elements significant to the practice of the invention.
FIG. 2 shows a pseudo-code implementation of a preprocessor of this invention.
FIG. 3 shows a pseudo-code implementation for classifying database commands according to this invention.
FIG. 4 shows a pseudo-code implementation for replacing database commands according to this invention.
FIG. 5 shows a pseudo-code implementation for replacing variable declaration database commands according to this invention.
FIG. 6 shows a pseudo-code implementation for replacing atomic database commands according to this invention.
FIG. 7 shows a pseudo-code implementation for replacing set database commands according to this invention.
FIG. 8 shows a pseudo-code implementation for replacing dynamic database commands according to this invention.
FIG. 9 shows a pseudo-code implementation for replacing transaction database commands according to this invention.
FIG. 10 shows a pseudo-code implementation for adding database commands to the bind file according to this invention.
FIG. 11 shows a pseudo-code implementation for debined program according to this invention.
FIG. 12 shows a pseudo-code implementation for the atomic command database interface function according to this invention.
FIG. 13 shows a pseudo-code implementation for a database interface function for initiating set-oriented data access according to this invention.
FIG. 14 shows a pseudo-code implementation showing a database interface function for accessing elements of set-oriented data accesses according to this invention.
FIG. 15 shows a pseudo-code implementation for a database interface function for terminating set-oriented data access according to this invention.
FIG. 16 shows a pseudo-code implementation of a database interface function for immediate execution of dynamic database commands according to this invention.
FIG. 17 shows a pseudo-code implementation for a database interface function for deferred execution of dynamic database commands according to this invention.
FIGS. 18-20 together comprise a flow diagram which illustrates the method of this invention.
FIG. 21 is a flow diagram illustrating Host Variable processing according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The invention is illustrated in its essential form in FIG. 1 of the drawings where reference numeral 10 indicates a first computer system which is approximately configured using conventional means to execute an application program, as well as the functions of this invention. The computing system 10 can be, for example, a mainframe machine of the 3090 type manufactured by and available from the IBM Corporation, The Assignee of this application. As is known, the 3090 computing system includes a CPU with a mainstore, input/output channel control means, direct access storage devices, and other I/O devices coupled thereto. Such a computing system may operate under the control of an operating system of the MVS type which executes application programs written in languages such as PL/1 or Cobol. The components of this invention which operate in this computing system can be written in, for example, the programming language called "C". A user interface to such a computing system would be any terminal provided with interactive time sharing under the TSO (time sharing option) available from the Assignee of this application. It is asserted that the environment established by the characteristics of the machine, language, and operating system of the first computing system 10 differs from the environment of the computing system 12. The computing system 12 can comprise, for example, a personal computer of the PS/2 type with an OS/2 EE operating system. Such a system can support a DBMS written in the "C" language which, in turn, supports a dialect of the well-known SQL language. A local agency for the purposes of this invention can be a program in the computing system 12 written in "C" language.
An application program 14 is written to execute on the computer system 10. However, database commands such as the command 16 are embedded in the program 14 in order to process data in the database of the computer system 12. Due to the difference between the environments of the systems 10 and 12, the command 16 (and other database commands in the application program) is written in a language which is different from the language in which the rest of the application program is written. The database commands are syntactically correct for execution on the computer system 12. However, they may include information such as variables, parameter values, and so on which are in a format acceptable to the computing system 10, but foreign to the computing system 12.
The invention concerns the preprocessing of the application program to identify the database commands, process and assemble them prior to compilation of the application program, and bind them in the computing system 12 for execution during run-time of the program 14. The invention also provides for the modification of the application program 14 to a form that is totally native to the computing system 10 by replacement of the database commands with calls in the language of the application program. After compilation of the application program, the invention response to the calls in the application program by requesting execution of the related database command by the computing system 12. The invention receives the results of the executed command on behalf of the application program.
The components for performing the functions of the invention reside in an application Access Agent 17. Preferably, the Access Agent 17 is a set of programs entered conventionally into the computing system 10 which are invoked using well-known techniques to perform the novel functions of the invention.
The primary components of the Access Agent 17 include a Preprocessor 18, a Bind program 38, and a Database Interface Function 40. Data structures which are built, filled, and used in the application Access Agent include a Bind file 20, a Host Variable table 30, and a cursor table 34.
The Preprocessor 18 analyzes the application program 14, recognizes database commands such as the command 16, and classifies the database commands based on syntactic cues. After the Preprocessor recognizes and classifies the database commands, it replaces them in a modified version 14a of the application program whose contents are unchanged except for the replacement of the embedded database commands. Once classified, database commands are further analyzed to produce, in the programming language of the application program, a database function invocation 28 whose type and content are dependent on the classification of the database command. When the Preprocessor 18 replaces a database command in the application program, it assigns a tag to that command, recognizes input and output Host Variables of the command, places them into the Host Variable table 30, correlates the replaced command with other related database commands, if necessary, and places an invocation (reference numeral 28 in FIG. 1) in the application program. The application program invocation 28 includes package name (explained below), tag, input variable structure parameters and output variable structure parameters, which are explained in detail below. Last, the Preprocessor 18 retains each database command, together with its tag assigned them, and a marker describing input and output variables in the Bind file 20. A modified command is indicated by reference numeral 22. The Bind file has an identifier, "NAME", and retains modified database commands until the Preprocessor 18 has completed modification of the application program. The Bind file is used as input to the Bind program 38 for binding of the commands to the DBMS in the computing system 12.
The function of binding the database commands extracted from the application 14 to a remote DBMS is assigned to the Bind program 38. The Bind program establishes communication with a named DBMS and then conducts a sequence of operations which send the entries in the Bind file 20 to the remote DBMS, with information required to bind the commands to the computing system 10 which executes the application process.
The Database Interface Functions 40 comprises a set of functions linked to the application program 14a when the program is compiled. The Database Interface Functions 40 effect the execution of database commands at a remote DBMS using a database command invocation protocol in response to invocation of the modified application program 14a, such as the invocation 28. When invoked from the application program, the Database Interface Functions 40 communicate the parameters in the invocation which identify the application program, the tagged database command which has been bound at the DBMS, and the variables necessary for execution of the command.
In order to appreciate the invention from the point of view of a relational DBMS, reference is again made to FIG. 1 wherein the computing systems 10 and 12 are connected by conventional communication access elements (which can include communication adapters 46 and 50 at each system) which are physically connected by an interface 48. The communication facility 46, 48, 50, is conventional. For the purposes of this invention, the facility is capable of identifying specific computers from their names, establishing communication between programs running on different computers, transferring data between connected communicating programs, and terminating communication between computers.
In the computing system 12, a Application Access Agent 52 conducts the binding protocol with the Bind program 38, passing tagged database commands received from the Bind program to a DBMS 54 which is identified by a name "ID". The DBMS 54 accepts the database commands and places them in a package 60 identified by the name "NAME" which identifies the application program 14a as the source of the package contents. One database command 62 with a tag is shown in the package 60. As is conventional, the identification "NAME" is the tie that "binds" the command to the application program 14. Packages are stored in a DBMS catalog 63. The DBMS 54 maintains a relational database contained in conventional storage 56.
Upon receipt of a message requesting execution of a database command from the Database Interference Functions 40, the Application Access Agent 52 interprets the received message to determine what services are requested of the DBMS 54. The agent 52 then requests the indicated services, waits for the response, and, upon receiving the response, passes the results of the services back to the Database Interface Function 40.
INTRODUCTION
The Preprocessor 18 is a critical link in the process of preparing the application program 14 for eventual execution(s). The Preprocessor 18 performs the following basic functions:
1. recognition and classification of database commands embedded in the application program;
2. replacement of database commands embedded in the application program with statements in the language of the application program which declare variables in that language or invoke the Database Interface programs; and
3. recording of database commands for eventual submission to the DBMS 54 by the Bind program 38.
The database command language Preprocessor 18 takes as input a file containing the instructions of the application program specified in some programming language. Interspersed with the programming language instructions are database commands expressed in the syntax of some database command language. To be concrete, we shall assume that the database command language is any of the several variants of SQL. The Preprocessor 18 recognizes the database commands and replaces them with statements of the application program language. The resulting (modified) application program 14a is one of the outputs of the Preprocessor 18 and is suitable for translation by a compiler for the application program language. A second output of the Preprocessor 18 is a retained list (e.g., file) containing certain of the database commands, some of which have been slightly modified by the Preprocessor 18. This second file, known as the Bind file 20, is an input to the Bind program 38 of the Application Access Agent.
FIG. 2 illustrates the high level function of the database command Preprocessor 18. Lines 100-103 show that the parameters of the database command Preprocessor are lists (e.g. files) containing the application program (input), the package name for the database commands of the application program (input), the modified application program (output), and the Bind file for the Bind program (output). Line 103 shows scanning the Application Program File. Lines 104-105 show recognizing database commands and copying lines which are not database command lines from the Application Program File to the Modified Program File. Lines 106-107 specify invocation of a classification module with the recognized command (input) and computed class (output) as parameters of the classification module. Lines 108-109 specify invocation of a replacement module with the recognized command and computed class as input parameters, a package name associated with the application program, and the tag assigned to the command as an output parameter. Lines 110-111 specify invocation of a module to add commands to the Bind file with the recognized command, its computed class and assigned tag as input parameters.
DESCRIPTION OF RECOGNITION AND CLASSIFICATION OF DATABASE COMMANDS
Database commands in a database command language (e.g., SQL) are recognized via syntactic cues that depend on a specific pre-processor implementation. These can be tags which precede the database command (e.g., the string "EXEC SQL"). Database commands can be classified into one of the following categories:
1. Host Variable declarations;
2. Atomic commands;
3. Set Oriented commands;
4. Dynamic commands; or
5. Transaction commands.
Host Variable declarations specify that a particular identifier (name) is to be a variable, of a particular type, which can be manipulated directly by statements of the application program language, as well as by database commands. Host Variable declarations are recognized by syntactic cues unique to each programming language (e.g., "BEGIN DECLARE SECTION" and "END DECLARE SECTION" for PL/1 variable declarations for SQL) and consist of an identifier and a type name.
Atomic database commands are commands which can be executed with a single interaction between the application program and the DBMS. They include Data Definition commands (e.g, "CREATE . . . ", "ALTER . . . ", "DROP . . . ", etc. in SQL), single row data selections, and Update, Delete, or Insert commands. Atomic database commands are recognizable by their syntactic prefix, e.g., the first or first and second words of the command in SQL. Some Atomic database commands may contain references to Host Variables. These Host Variable references are distinguished by being preceded by an easily recognizable mark (e.g., a ":" in some SQL implementations). Host Variable references may be for input to the database command or to receive results (output) from the database command. The distinction must be made between input and Output Host Variables. In SQL Output Host Variables follow the keyword "INTO". Toe accommodate language enhancements whose syntactice prefixes are not known by the Preprocessor, these unknown database commands are classified as atomic database commands and all the host variable references are taken to be input variables.
Set oriented database commands consist of the following types:
1. commands to specify a set of database items (e.g., "DECLARE CURSOR . . . " in SQL);
2. commands to initiate processing of a set of database items (e.g., "OPEN . . . " in SQL);
3. commands to access the next element of a set of database items (e.g., "FETCH . . . " in SQL);
4. commands to terminate processing of a set of database items (e.g., "CLOSE . . . " in SQL).
The Preprocessor 18 of the Application Access Agent must recognize and handle each of these Set Oriented commands specially. Recognition and classification is again based on the initial keywords of the database command.
Dynamic database commands allow an application program to postpone specification of a database command until execution of the application program. Dynamic database commands are submitted to the DBMS for analysis, optimization, (temporary) retention, and execution during the execution of the application program. Dynamic database commands are specific, distinguishable commands in the application program which indicate that the actual database command will be provided during execution. The database command to be executed is a parameter of the dynamic database command and may be supplied from a string type Host Variable. Like other database commands, dynamic database commands can be recognized by then reading keywords (e.g., "EXECUTE IMMEDIATE . . . ", PREPARE . . . " in SQL).
Transaction commands are database commands for committing or aborting the current database transaction. In some SQL implementations, the Transaction commands are "COMMIT WORK" and "ROLLBACK WORK".
FIG. 3 illustrates the classification module of the Preprocessor 18. This illustration shows classification of database commands using the concrete example of SQL. Lines 200-201 show that the parameters of the Preprocessor classification module are a database command (input) and the determined class (output). Lines 202-207 show that database commands encountered while with a SQL DECLARE scope are classified as Host Variable commands unless the command begins with "END DECLARE". Line 209 is a multi-way branch statement based upon the leading words of the Database Command. The five cases of the multi-way branch (lines 210, 213, 215, 217, and 219) set the computed class of the Database Command. Note that in most cases, several different database commands will cause a branch to be satisfied.
The Preprocessor 18 in the application program computer analyzes the application program, recognizes database commands, and classifies them based on syntactic cues rather than a complete parsing of the full database command. Both the recognition of database commands and their classification are accomplished without knowledge of, and independently of, the specific intended remote DBMSs at which the application program's database commands will be bound. The classification step examines only the initial keyword(s) of database commands, and therefore it is independent of the idiosyncracies of the database command language syntax that follows. As an example of classification, the statement EXEC SQL CREATE TABLE EMP (NAME CHAR(23)); would be recognized by the classification module as an SQL database command and would be classified as an Atomic command.
DESCRIPTION OF REPLACEMENT OF DATABASE COMMANDS
Each recognized and classified database command in the application program 14 must be replaced with application program programming language statements which cause the command to be executed. In general, for each database command of the application program, the Preprocessor 18 will replace the database command with a call to a Database Interface Function. The Database Interface Functions 40 are responsible for causing the database commands to be executed in a remote DBMS by communication with that DBMS via a communication protocol. The conventions for passing parameters to Database Interface Functions depend on the computer environment of the application program and Application Access Agent programs and are left to the needs of the implementer.
Host Variable declarations are replaced by the language statement corresponding to the declaration of a language variable with the same name as the name in the Host Variable declaration and the same type. The Host Variable name and type are also recorded in the Host Variable Table 30, which is an associative table managed by the Preprocessor 18. The Host Variable Table is used by the Preprocessor 18 during replacement and Bind file processing.
Atomic database commands are replaced by calls to the Database Interface Function 40 for executing Atomic commands. In order to indicate which database command retained at the remote DBMS is to be executed, a mechanism for identifying retained database commands is required. For this, the invention identifies the set of database commands of an application program and identifies each of the database commands of the application program.
The invention identifies a package (the set of database commands of an application program) with a name that is unique to the remote DBMS which retains and executes the commands. While many naming conventions are possible in the invention, the name of a package of an application program is the name of the "family" of the application program followed by the name of the application program. In the Figures, the name is "NAME". The individual database commands of an application program package are identified by tags (e.g., numbers) assigned by the Preprocessor 18, placed in the Bind file, and communicated to the DBMS by the Bind program 38.
The call to the Database Interface Function which replaces an Atomic database command includes parameters specifying the package name and database command tag. The call to the Database Interface Function for Atomic database commands must also communicate values for the Input Host Variables of the command (if any) and receive values of the Output Host Variables (if any). The mechanism used by the invention is to search the database command for Host Variable cues (a ":" or following "INTO" or "USING" for some implementations of SQL) and add parameters to the Database Interface Function to call to pass (or receive) the values of the corresponding variables of the host language. The Preprocessor 18 must also consult the Host Variable Table to insure that the indicated Host Variables are declared. Each Host Variables is removed and replaced with a marker denoting a replaced Host Variable by type, size, format, etc.
All the set oriented database commands relating to the same set of database items are grouped together based on their shared Cursor Name, which is easily extracted from the database command. The same database command tag is associated with all the commands relating to the same set of Database items. Set specification commands are simply removed from the application program. However, the Preprocessor program assigns a database command tag and associates it with the Cursor Name found in the set specification command. Another associative table, the Cursor Table 34, is maintained by the Preprocessor 18 to record the association between Cursor Names and database command tags. The remaining set oriented database commands are replaced with calls to Database Interface Functions specific to the (sub)class of the command. The set processing initiation and access commands may have Host Variables. Processing for the Host Variables of these set oriented database commands is similar to that for the Atomic database commands. As described earlier, Host Variables contained in Atomic database commands whose initial syntactice prefix was not recognized and understood by the Preprocessor are assumed to be input variables.
Dynamic database commands are processed similarly to Atomic or set oriented database commands. A tag is assigned to the dynamic database command. Dynamic database commands specify another database command to be submitted for immediate analysis, optimization, and execution, or a database command to be submitted with one dynamic database command and executed with another. The distinction is syntactically evident in the corresponding database commands. In the case of immediate execution ("EXECUTE IMMEDIATE . . . " in SQL), the Preprocessor 18 assigns a tag to the database command and replaces ti with a call to the Database Interface Function for immediate execution of dynamic database commands. In the case of deferred execution, the dynamic database command ("PREPARE . . . " in SQL) contains a label which can be referenced in other database commands to effect the execution. The Preprocessor 18 assigns a database command tag to the command and associates that tag with the label in the command using an associative Label table 36. The deferred execution dynamic database command (i.e., "PREPARE . . . " in SQL) is replaced with a call to the Database Interface Function for deferred execution dynamic database commands. The database command to be submitted by a dynamic database command may be specified by a character string literal expression or by a text string type Host Variable and the call to the Database Interface Function must take this into account and pass the correct text string containing the database command to be processed, The database command for executing a deferred dynamic database commands (e.g, in SQL either "EXECUTE <label> . . . " or "OPEN <label> . . . " followed by "FETCH <label> . . . and "CLOSE <label> . . . ") is replaced with a call to the Database Interface Function 40 for executing that statement. The call to the Database Interface Functions 40 uses, as a parameter, the database command tag, from the Label Table 36, associated with the "PREPARE . . . " command which causes the dynamic database command to be analyzed, optimized, and (temporarily) retained. The Database Interface Functions used to execute dynamic database commands are the same ones used for Atomic or set oriented database commands.
Transaction database commands are replaced by calls to the appropriate transaction Database Interface Function.
FIG. 4 illustrates the high level function of the program replacement process of the application program Preprocessor 18. Line 300 shows that the replacement process takes as input parameters a database command, its class, and the name of the package of database commands for the application program. The tag assigned to the command is an output parameter. Line 301 is a multi-way branch on the class of the database command. The remaining lines (302-312) call modules specialized in the replacement of application program text for specific classes of database commands.
FIG. 5 illustrates the function of the program module for replacement of Host Variable declarations using SQL as a concrete example. Line 400 shows the parameters of this module. Line 401 analyses the Database Command parameter to determine the name of the program Host Variable and its type. Line 402 enters the Host Variable into the Host Variable Table 30. Line 403 produces code in the language of the application program 14 and adds to it to the Modified Program File. An application program language dependent module ("AP Language Declaration") produces code in the language of the application program to declare a variable with the specified Name and Type.
FIG. 6 illustrates the function of the program module for replacement of Atomic database commands using SQL as a concrete example. Line 500 shows the parameters of this module. Line 501 allocates a tag for the database command. Lines 502-503 identify the Input Host Variables by searching the database command for the simple keywords or punctuation which signify the presence of an Input Host Variable. The identification of Input Host Variables also checks that the identified Host Variables are present in the Host Variable Table. Lines 504-509 add code to create a descriptive structure which can be used by Database Interface Functions to access the values of the Host Variables during execution. An application program language dependent module ("AP Language Host Variables") produces code in the language of the application program to create and fill the structure to describe the location and type of the Input Host Variables and returns the "name" of that structure. Lines 510-517 perform a similar function for Output Host Variables. Lines 518-521 add to the Modified Program File code in the language of the application program to call the Database Interface Function 40 for executing Atomic database commands using a language dependent module ("AP Language DIF call"). The necessary parameters for invocation of the "Atomic DIF" Database Interface Function are shown on lines 519.520.
FIG. 7 illustrates the function of the program module for replacement of the class of set oriented database commands using SQL as a concrete example. Line 600 shows the parameters of this module. Line 601 is a multi-way branch on the first word of the database command. The first CASE of the multi-way branch (lines 602-605) processes the database command for specification of a set of database items as the database command result. Line 603 allocates a tag for the database commands relating to the same result set (i.e., the same Cursor name in SQL). Lines 604-607 determine the Cursor name for the command and associates that name with the allocated tag in the Cursor Table 34. Lines 605 and 606 convey the input and output Host Variables in the Set Oriented specification to where they are needed when replacing the initiating and access commands (OPEN and FETCH). These are saved in the Cursor Table. Thus, for a later instance of FETCH, either the output variables are used accompanying the FETCH or, if none, the output variables saved in the Cursor Table from the DECLARE -- CURSOR are used. This also applies to the OPEN statement. The second CASE of the multi-way branch (lines 608-621) processes the database command for initiation of processing of the database command result set. Lines 608-609 determine the Cursor name of the database command and the tag associated with the Cursor name. Lines 611-618 process Input Host Variables in a manner similar to Host Variable processing in the replacement for Atomic database commands. Lines 619-621 add to the Modified Program File code in the language of the application program to call the Database Interface Function for initiating processing of set oriented database commands using a language dependent module ("AP Language DIF call"). The necessary parameters for invocation of the "Set DIF open" Database Interface Function are shown on line 620. The third CASE of the multi-way branch (lines 622-635) processes the database command for accessing the database items in the database command result set. Lines 623-624 determine the Cursor name of the database command and the tag associated with the Cursor name. Lines 625-632 process Output Host Variables in a manner similar to Host Variable processing in the replacement for Atomic database commands. Lines 633-635 add to the Modified Program File code in the language of the application program 14 to call the Database Interface Function for accessing a database item in the result set of a set oriented database command using a language dependent module ("AP Language DIF call"). The necessary parameters for invocation of the "Set DIF fetch" Database Interface Function are shown on line 634. The last CASE of the multi-way branch (lines 636-641) process the database command for terminating processing of the result set of a set oriented database command. Lines 637-638 determine the Cursor name of the database command and the tag associated with the Cursor name. Lines 639-641 add to the Modified Program File code in the language of the application program 14 to call the Database Interface Function 40 for termination of processing result set of a set oriented database command using a language dependent module ("AP Language DIF call").
FIG. 8 illustrates the function of the program module for replacement of dynamic database commands using the example of SQL. Line 700 shows the parameters of this module. Line 701 is a multi-way branch on the first word of the database command. The first CASE of the multi-way branch (lines 702-712) processes the database command for specifying a database command for deferred execution. Line 703 allocates a tag for the database commands which specify and eventually execute the dynamically supplied database command. Lines 704-705 determine the Label of the dynamically specified and executed database command and associate that Label with the allocated tag in the Label Table 36. Line 706 enters the label into the Cursor Table where it must be in order to be found by the Preprocessor 18 in case the execution of the Dynamic deferred statement is "OPEN Lable . . . ", for example. Lines 707-710 add code to create a descriptive structure which can be used by the Database Interface Function to access the text value of the dynamically defined database command during execution. An application program language dependent module ("AP Language Command String") produces code in the language of the application program to create and fill the structure to describe the location of the text string containing the dynamically specified database command and returns the "name" of that structure. Lines 711-713 add to the Modified Program File code in the language of the application program to call the Database Interface Function for dynamically specifying a database command for deferred execution using a language dependent module ("AP Language DIF call"). The necessary parameters for invocation of the "Dyn DIF defer" Database Interface Function are shown on line 712. The second CASE of the multi-way branch (lines 714-740) processes the database command for immediate or deferred execution of dynamically specified database commands. Lines 715-724 handle the case of immediate execution of a dynamically specified command. Line 716 allocates a tag for the command. Lines 717-720 generated code in the Modified Program File in a manner similar to that used in the "PREPARE" case of this module. Lines 721-724 add to the Modified Program File code in the language of the application program to call the Database Interface Function for immediate execution of a dynamically specified database command using a language dependent module ("AP Language DIF call"). The necessary parameters for invocation of the "Dyn DIF immed" Database Interface Function 40 are shown on line 724. Lines 725-740 handle the case of deferred execution of a dynamically specified database command. Lines 727-735 process Input Host Variables in a manner similar to Host Variable processing in the replacement for Atomic database commands. Lines 737-740 add to the Modified Program File code in the language of the application program to call the Database Interface Function 40 for initiating the deferred execution of dynamically specified database commands using a language dependent module ("AP Language DIF call"). The necessary parameters for invocation of the "Atomic DIF" Database Interface Function are shown on line 740.
FIG. 9 illustrates the function of the program module for replacement of transaction database commands using the concrete example of SQL. Line 800 shows the parameters of this module. Line 801 is a multi-way branch on the first word of the transaction database command. Lines 802-805 add to the Modified Program File code in the language of the application program 14 to call the Database Interface Function for initiating transaction commit. Lines 806-809 add to the Modified Program File code in the language of the application program 14 to call the Database Interface Function for initiating transaction abort.
In summary, after the database commands are recognized and classified as described above, the commands are replaced in a modified version of the application program 14a whose contents are unchanged except for the replacement of the embedded database commands. Database commands classified as Host Variable Declarations are placed without modification into the modified application program. The other database commands are further analyzed to produce a Database Interface Function invocation in the programming language of the application program whose type and contents are dependent on the classification of the database command. This replacement is accomplished by assignment of a tag (if needed) to be used in later execution of that command, recognition of input and Output Host Variables (if any) and placement of them into a structure dependent on the application program's language, correlation (if needed) with related database commands, and placement of an invocation of the appropriate Database Interface Function in the appropriate programming language that includes the following parameters: package name, tag, input variable structure, and output variable structure.
The replacement of database commands in the application program depends solely on syntactic cues rather than a complete parsing of the full database command. This replacement is accomplished without knowledge of, and independently of, the DBMS 54 at which the application program's database commands will be bound. The replacement step examines only the initial keyword(s) of database commands, and the Host Variables (which are recognized by syntactic cues) and therefore it is independent of the idiosyncracies of the database command language syntax that follows.
The following set of SQL database commands embedded in Pl/I illustrates the mechanism described above for replacement of database commands in the application program. Assume that the application program contains the following database commands:
______________________________________EXEC SQL BEGIN DECLARE SECTION; DCL PARTNO BIN FIXED(15); DCL DESCR CHAR(10); DCL NAME CHAR(15);EXCE SQL END DECLARE SECTION;EXEC SQL SELECT PARTNUM, DESCRIPTIONINTO :PARTNO, :DESCRFROM INVENTORYWHERE PARTNAME = :NAME;______________________________________
An instance of the replacement mechanism above would produce the following:
______________________________________ DCL PARTNO BIN FIXED(15); DCL DESCR CHAR(10); DCL NAME CHAR(15);CALL ATOMICDBINTFN(packageP,tag1,IVARS(1, (TYPE(NAME),ADDR(NAME))),OVARS(2, (TYPE(PARTNO),ADDR(PARTNO)), (TYPE(DESCR), ADDR(DESCR))));______________________________________
DESCRIPTION OF BIND FILE GENERATION
The Preprocessor 18 must prepared the information needed by the Bind program to bind the database commands of the application program to a remote DBMS. This information consists of the text of (some of) the database commands embedded in the application program. Only Atomic and one type of set oriented specification database commands (in the case of SQL, DECLARE CURSOR) need to be entered into the Bind file 22. The Input Host Variable references (variable names) embedded in the database commands which are inserted into the Bind file are replaced with simple Host Variable markers. Furthermore, these markers are associated with the types of the Host Variables referenced by the database command. This association may be by appending a positional list of type names, or by placing the type name following the Host Variable mark in the database command. This module of the Preprocessor uses the Host Variable table defined above to determine the types of the Host Variables referenced by the database command. Note well that this replacement of the Input Host Variable references allows application program language specific Preprocessor programs to recognize and process not only simple Host Variable references, but also expressions over Host Variables. This advanced facility can be supplied for different languages, and to different degrees by different implementations of the Preprocessor program of the Application Access Agent without requiring changes to either the Bind program, Database Interface Functions, communication protocols, or DBMS implementations. (Of course, complex Host Variable expressions in database commands might impact the code which invokes the Database Interface Functions in order to compute the value of the Host Variable expressions.) References to Output Host Variables can be removed from the database commands appended to the output Bind file.
FIG. 10 illustrates the function of the program module of the Preprocessor 18 for constructing the Bind file 22 which is an input to the Bind program 38 of the Application Access Agent. Line 900 shows the parameters of this module. Line 901 is a multi-way branch on the Class of the database command. Line 902 intercepts database commands which do not need to be added to the Bind file. Lines 903-905 add Atomic database commands to the Bind file. The module "Fix Up Host Variables" replaces the names of input Host Variables in the database command with markers and adds the type of the Host Variable (either following the marker or in an ordered list associated with the database command). It also may remove references to Output Host Variables from the database command. Line 905 adds the Database command, as modified by "Fix Up Host Variables", to the Bind file. Lines 906-909 process set oriented database commands. Line 907 limits this processing to the commands which specify the result set of database items. Lines 908-909 perform the same function as in lines 904-905.
In summary, since the Preprocessor 18 of the Application Access Agent 17 executes independently of the binding of database commands to a specific remote DBMS, it is necessary during pre-processing to retain certain database commands in modified form, together with the tag used in the modified application program to identify each database command. The Bind file is the mechanism by which this information is retained. This Bind file will be used as input to the Bind program of the Application Access Agent during binding to the remote DBMS.
This invention permits the Preprocessor 18 of the Application Access Agent to be executed once and the results (Bind file 22) bound at different times to several different DBMSs. Therefore this invention is more efficient than alternative mechanisms that perform pre-processing and binding in a single step, because both steps would have to be executed for each DBMS to which the application program is bound. Furthermore, such alternative mechanisms require using and holding remote DBMS resources during the recognition, classification, and replacement of database commands in the application program. In this invention, these steps are performed independently of the binding to any specific DBMS and do not require resources at any remote DBMS during the Pre-processor execution.
Following the example given above, a Bind file entry is illustrated that is generated from the application program in:
______________________________________TAG = TAG1COMMAND = SELECT PARTNUM, DESCRIPTIONFROM INVENTORYWHERE PARTNAME = :CHAR(15)______________________________________
THE BIND PROGRAM OF THE APPLICATION ACCESS AGENT
Introduction
The Bind program 38 of the Application Access Agent 17 interacts with a remote DBMS to effect the binding (analysis, optimization, and retention) of database commands from the application program 14. The Bind program takes as input the following items:
1. a Bind file prepared by the Preprocessor;
2. the name of the remote DBMS at which the database commands should be bound; and
3. processing options to be used by the remote DBMS for binding the database commands.
The binding of the database commands is accomplished using an agreed upon communication protocol between the Bind program at the application program computer and the DBMS at a remote computer.
DESCRIPTION OF THE BIND PROGRAM
The Bind Program 38 first determines the communication address of the named remote DBMS using mechanisms which may be particular to the computing environment of the application program computer. Then the Bind program establishes communication with the remote DBMS. Establishment of communication may involve identifying the user on whose behalf the Bind program is executing. The mechanisms for establishing communication and for user identification are outside the scope of this invention. Once communication is established, the Bind program 38 indicates that it wishes to initiate binding database commands using an agreed upon message format. This message, the BEGIN -- BIND contains the bind processing options to be used by the DBMS to process the database commands to be bound. Bind processing options can include the name of the package of database commands to be constructed, whether the package is new or replaces a package of the same name, parsing rules (e.g., the symbol used to delimit text string literals in database commands), and the authorized user responsible for the application program package.
Having established communication and received an acceptable response to the bind initiation message, the Bind program 38 of the Application Access Agent transmits each database command in the Bind file 20 to the DBMS using another agreed upon message format. This message, the BIND -- DATABASE -- COMMAND message, contains the database command 22 as modified by the Preprocessor 18 and the tag associated with that database command. Note that the Input Host Variable references in the database command no longer carry Host Variable identifiers, but rather the type of the value to be passed to the DBMS when the database command is executed. The remote DBMS, upon receipt of a BIND -- DATABASE -- COMMAND message, will analyze, optimize, and retain the database command contained in the message. The database command will be incorporated into a package of database commands (whose name was specified in the BEGIN -- BIND message) for eventual executions by the application program and will be associated with the tag received in the BIND -- DATABASE -- COMMAND. Together, the package name and the tag uniquely identify the analyzed and optimized database command. If errors are detected by the DBMS, they are reported in a response message to the Bind program and the database command is not retained in the package. Otherwise, the DBMS signals acceptance of the database command in its response message. When all the database commands from the Bind file 38 have been sent to the remote DBMS in BIND -- DATABASE -- COMMAND messages, the Bind program requests completion of the package resulting from the binding of the database commands via an END -- BIND message. Upon receipt of an END -- BIND message the DBMS completes the package and its optimized database commands by "committing" changes to the catalogs of the DBMS and responds with an acknowledgement message indicating the outcome of the attempt to "commit" the package. END -- BIND completes the processing o the package according to the Processing Options accompanying the BEGIN -- BIND message and the events that occurred during the processing of each BIND -- DATABASE -- COMMAND. Typically, this will result in the retention of the package in the DBMS when no errors are encountered. If the Bind program or the DBMS terminates during binding of database commands, or if a communication failure interrupts binding of database commands, or if errors are detected in one or more database commands sent via bind -- database command messages and the Processing Options specify that a package should not be created if errors occur, the package is not retained by the remote DBMS.
FIG. 11 illustrates the processing of the Bind program 38 of the Application Access Agent 17 using SQL as a concrete example. Line 1000 illustrates the parameters which are passed to the Bind program. Line 1001 establishes communication with the DBMS specified by the DBMSname parameter. Lines 1002-1004 illustrate the initiation of the bind process with the sending of the BEGIN -- BIND message containing the package Name and the bind processing options. Lines 1005-1008 send the database commands and their tags to the remote DBMS in BIND -- DATABASE -- COMMAND messages. Lines 1009 terminates the binding processing with the sending of an END -- BIND message to complete processing of the package being created.
Since the Preprocessor 18 executes independently of the binding of database commands to a specific remote DBMS, the function of binding to a remote DBMS is performed by the Application Access Agent 17 using the Bind file 20 produced by the Bind file generator mechanism of the Application Access Agent. The bind process initiates the binding of a package at a named DBMS by establishing communication with that DBMS, and sending a BEGIN -- BIND message to that DBMS together with the information needed at the DBMS to create a package, including the package name and Processing Options. Following bind initiation, the entries in the Bind file 20 at the application program computer 10 are sent to the remote DBMS, including the tag used in the modified application program and its associated database command as parameters to BIND -- DATABASE -- COMMAND messages. After all the entries in the Bind file have been sent to the remote DBMS and processed there, the bind process terminates binding by sending the END -- BIND message.
This mechanism permits the Bind file entries for the application program 14 to be bound at different times to several different DBMSs. Furthermore, it permits the cost of analyzing and optimizing each database command to be amortized over possibly several executions of that database command, possibly invoked by multiple instances of the application program at the same time or at different times, by the same user or different users. Since communications costs can be relatively expensive, the elapsed time (and thus the communication expense) to perform the execution of an already optimized database command can be significantly less than the elapsed time needed to analyze and optimize it. This is an additional advantage of this invention over alternative mechanisms which analyze and optimize database commands for each execution request or for each invocation of the application program.
The following elaboration of the example given above illustrates package contents resulting from binding a Bind file entry that was generated from the application program:
__________________________________________________________________________PACKAGEname, ProcOpts, Number of database commands = 1: Optimized code for TAG1:Expect one input variable of type CHAR(15)Use (internal access path) to access (internal database table name) with key = input variable.Produce (internal element name1, internal element name2) as output Original database command for tag1: SELECT PARTNUM, DESCRIPTIONFROM INVENTORYWHERE PARTNAME = :CHAR(15)__________________________________________________________________________
DESCRIPTION OF DATABASE INTERFACE FUNCTIONS OF THE APPLICATION ACCESS AGENT
Introduction
The Database Interface Functions 40 of the Application Access Agent are programs which effect execution of database commands at a remote DBMS using the database command invocation protocol. Database Interface Functions 40 are linked to the application program and called from the (modified) application program during the execution of the application program. The exact interface between Database Interface Functions and the application program may depend on the computing environment of the application program computer 10. Database Interface Functions obey a communication protocol agreed upon with the remote DBMS to effect the execution of bound database commands in packages at the remote DBMS. Database Interface Functions are responsible for communicating the values of Input Host Variables to the remote DBMS and for setting the values of Output Host Variables to the values returned from the remote DBMS as a result of executing a database command.
In response to (or prior to) the first call to a Database Interface Function 40 during the execution of an application program, the Application Access Agent 17 must establish communication with the remote DBMS 54. The mechanism for determining which remote DBMS and its computer (address) is dependent upon the computing environment of the application program computer. Establishment of communication may involve identifying the user on whose behalf the application program is executing. The mechanisms for user identification are outside the scope of this invention. Establishment of communication may involve exchanging agreed upon messages to identify the services needed, the DBMS to be used, and the level (or version) of the communication protocol to be used in subsequent communication.
This section describes the Command invocation protocol (i.e., the messages exchanged between the Database Interface Functions of the Application Access Agent and the remote DBMS) as well as the actions taken by the Database Interface Functions and the remote DBMS in response to messages of the protocol.
DESCRIPTION OF THE ATOMIC DATABASE COMMAND DATABASE INTERFACE FUNCTION
The Database Interface Function which is called from an executing application program to perform and Atomic database command constructs and transmits an EXECUTE -- ATOMIC -- COMMAND message to the remote DBMS. The EXECUTE -- ATOMIC -- COMMAND message contains the following elements:
1. the name of the application program package in which the command is located;
2. the tag of the particular Atomic database command;
3. the values of the Input Host Variables of the Atomic database command; and
4. a description of the types of the Input Host Variable values.
The Atomic database command Database Interface Function must access the values of the Input Host Variables and construct a description of their types for inclusion in the EXECUTE -- ATOMIC -- COMMAND message. Note that the information needed to construct the EXECUTE -- ATOMIC -- COMMAND is included in the information passed to the Database Interface Function by the modified application program. Upon receipt of an EXECUTE -- ATOMIC -- COMMAND message, the remote DBMS 54 locates the retained execution plan for the indicated database command in the package indicated by the package name in the received message. If this step succeeds, the remote DBMS 54 executes the plan for the located database command using the Input Host Variable values received in the EXECUTE -- ATOMIC -- COMMAND message. If execution of the Atomic database command is not successful, the DBMS prepares and transmits a message to the Database Interface Function with an indicator, in an agreed upon format, describing the reason why execution did not succeed. If the execution is successful, and the database command in question produces results consisting of one or more result values (i.e., the original database command contained Output Host Variables), these values, along with descriptions of their data types, are turned to the Database Interface Function in a message in the agreed upon format. The Database Interface Function 40 then copies the returned result values into the corresponding Output Host Variables of the application program. (Note that conversions from the value representations of the DBMS to the corresponding value representation in the application program computing environment may be necessary. The mechanisms to specify and support such value transformations are beyond the scope of this invention.)
FIG. 12 illustrates the Database Interface Function and Command Execution protocol for Atomic database commands. Line 1100 shows the invocation of "Atomic DIF" with the parameters prepared during replacement of database commands. Note that the InHVstruct and OutHVstruct contain both references to Host Variables and the types of the referenced Host Variables. Note also that either or both of the InHVstruct and outHVstruct may be empty. Lines 1101-1102 use the InHVstruct to obtain values for the Input Host Variables and construct a description of their types. Lines 1103-1105 send an EXECUTE -- ATOMIC -- COMMAND message. Line 1106 receives the response and checks for errors. Lines 1107-1110 copy any received result values into Output Host Variables. Conversion between compatible types and different representations of the same type may occur during copying of Output Host Variables.
DESCRIPTION OF SET ORIENTED DATABASE COMMAND DATABASE INTERFACE FUNCTIONS
Introduction
The Database Interface Functions which are called from the executing application program to perform set oriented database commands are somewhat more complicated. Set oriented database commands produce (possibly large) sets of result values. Because the cost of sending and receiving messages via today's communication facilities is relatively high, it is of great importance to minimize the number of message exchanges needed to execute set oriented database commands. To this end, when set oriented data access is initiated by an executing application program (i.e., "OPEN . . . " in SQL), the corresponding Database Interface Function constructs and transmits a OPEN -- QUERY message which instructs the remote DBMS to response, in a single response message, with multiple result elements. Subsequently, the Database Interface Function for accessing Set data access results either returns the next, already received, result element, or demands another group of result elements from the remote DBMS using a CONTINUE -- QUERY message.
However, if update or delete of the current result set element database commands ("UPDATE CURRENT OF CURSOR . . . " or "DELETE CURRENT OF CURSOR . . . "in SQL) are to be processed, the return of multiple result elements must be suppressed. This is because the update and delete current element database commands operate on the "current" element of the result set. Fortunately, the DBMS in its analysis of the set oriented specification database commands ("DECLARE CURSOR . . . FOR UPDATE" in SQL) and its association of current element update or delete database commands with the corresponding set specification command can determine when result elements of a set oriented database command might be updated or deleted. If the DBMS determines that update or delete of a result element is possible, it will return only a description of the data in response to OPEN -- QUERY and a single result element in response to OPEN -- QUERY and CONTINUE -- QUERY messages.
Because processing of the result elements of a set oriented data access involves multiple database commands of the application program, the set oriented database command Database Interface Functions maintain an Active Cursor Table 34 to record the status of active set oriented data accesses. The Active Cursor Table associates the tag of the Set Oriented commands with the following information:
1. status of OPEN or CLOSED;
2. description of types of result element values;
3. a sequence of already received elements of the result set; and
4. indications of which received elements have been accessed.
DESCRIPTION OF DATABASE INTERFACE FUNCTION FOR INITIATING SET ORIENTED DATA ACCESS
The Database Interface Function responsible for initiating processing of set oriented data access (e.g., in response to "OPEN . . . " in SQL) constructs and transmits a message to the remote DBMS, in the agreed upon format of an OPEN -- QUERY message, containing the following elements:
1. the name of the application program package in which the command is located;
2. the tag of the particular set oriented database command;
3. the values of the Input Host Variables of the set oriented database command;
4. a description of the types of the Input Host Variable values; and
5. an indication of how much of the result set should be returned.
The specification of how much of the result set should be returned can take several forms. Either a number of result elements or the amount of space available to receive result elements can be agreed upon. (Another alternative is to allow the DBMS to attempt to return the entire set of result elements and make use of flow control or pacing features of the communication facility to regulate the flow of result elements.) The remote DBMS, upon receipt of an OPEN -- QUERY, must locate and access the retained execution plan for the indicated set oriented data access. If this succeeds, execution of the retained plan is initiated using the received Input Host Variable values and as many result elements as requested (or will fit in the space indicated) will be produced and formatted into a reply message in an agreed upon format. If the DBMS has determined that the set oriented database command may be subject to set oriented updates or deletes, it will return only the description of the data in response to OPEN -- QUERY and a single result element in response to CONTINUE -- QUERY. In both these cases, the DBMS suspends execution of that command such that execution can be resumed to produce further result elements at a later time. If the production of result elements exhausts the set of elements specified by the database command before exceeding the quantity of result elements specified in the OPEN -- QUERY message, an indication that the set is exhausted is returned with the reply message and the database terminates processing of the query.
The elements of the reply message to the OPEN -- QUERY message contains the following elements:
1. a description of the data types of the values of a single result element or row in SQL;
2. a sequence of result elements; and
3. a indication of successful, "end of query", or unsuccessful execution.
The Database Interface Function which initiates processing of set oriented database commands receives the response message from the DBMS and checks the indicator as to whether execution was successful. If not an error indication is returned to the application program. If successful, the Database Interface Function enters the command tag, data type descriptions, and sequence of elements into the Active Cursor Table 37. If the DBMS indicated that the result set was exhausted, the status in the Active Cursor Table is set to CLOSED; otherwise to OPEN.
FIG. 13 illustrates the Database Interface Function and Command Execution protocol for initiating set oriented data access. Line 1200 shows the invocation of "Set DIF open" with the parameters prepared during replacement of database commands. Lines 1201-1202 process Input Host Variables similarly to the processing described for the Atomic command Database Interface Function. Line 1203 sends a OPEN -- QUERY message. Lines 1204-1205 receive the response and check for errors. Lines 1206-1211 add the set being processed to the Active Cursors. The pseudocode for this and the subsequent set oriented Database Interface Functions represent access to members of the Active Cursors by bracketed expressions, such as the one on line 1209. Also, in the interest of clarity, mechanisms for keeping track of which received elements of the result set have been accessed are not explicitly represented. Note that lines 1210-1211 may set the status of the Active Cursors to CLOSED before any result elements have been accessed. This allows the CLOSE -- CURSOR message to be avoided (see Pseudocode for termination of set oriented data access).
DESCRIPTION OF DATABASE INTERFACE FUNCTION FOR ACCESSING ELEMENTS OF SET ORIENTED DATA ACCESSES
The Database Interface Function responsible for accessing elements of set oriented data accesses is called from the application program to obtain the values of the next element of the result set ("FETCH . . . " in SQL). This Database Interface Function must determine that the set oriented database command has been initiated by examining Active Cursor Table 37. If access has not been initiated, an error is reported to the application program. Otherwise, the Database Interface Function determines whether there are elements which have been received from the remote DBMS and not yet accessed by the application program. If there are unaccessed elements, the Database Interface Function copies the values of the next unaccessed element into the Output Host Variables of the application program, using the type description returned from the remote DBMS and maintained in the Active Cursor Table. The element Database Interface Function also marks the (newly) accessed element as accessed. If the status in the Active Cursor Table is CLOSED, and all received elements have been accessed, the element access Database Interface Function returns the set exhaustion ("end of query") error to the application program.
If all the elements already received for the particular set oriented data access have been accessed and the status is OPEN, the Database Interface Function constructs and transmits a message in the agreed upon format of a CONTINUE -- QUERY message. The elements of a CONTINUE -- QUERY message are:
1. the name of the application program package in which the command is located;
2. the tag of the particular set oriented database command; and
3. an indication of how much of the result set should be returned.
Upon receipt of a CONTINUE -- QUERY message, the remote DBMS determines whether the indicated database command from the indicated package has been initiated. If not, an error indication is returned in an agreed upon message format. If the indicated database command has been initiated, the remote DBMS resumes execution of the plan for that database command to produce additional result elements and assembles as many result elements as were requested (or will fit in the indicated space) into a reply message in an agreed upon format. If the DBMS (in its infinite wisdom) has determined that the set oriented database command may be subject to set oriented updates or deletes, a single result element is returned. If the production of result elements exhausts the set of elements specified by the set oriented database command before exceeding the quantity of result elements specified in the CONTINUE -- QUERY message, an indication that the set is exhausted is returned with the reply message and the DBMS terminates processing the query. The element access Database Interface Function associates the received result elements and DBMS set exhaustion indication with the Active Cursor Table entry. If any elements were returned from the remote DBMS, the first of them is copied to the Output Host Variables of the application program and marked as having been accessed.
FIG. 14 illustrates the Database Interface Function and Command Execution protocol for accessing elements of set oriented data accesses. Line 1300 shows the invocation of "Set DIF fetch" with the parameters prepared during replacement of database commands. Lines 1301-1302 check whether processing has been initiated for the set specified by the package and tag parameters. If there are already received but unaccessed elements, lines 1303-1306 copy the values of the next such element into output Host Variables in ways similar to those of the Atomic command Database Interface Function. Otherwise, lines 1307-1308 report "end of query" to the application if an "end of query" response has been received from the DBMS. If the already received elements have all been accessed, and "end of query" not been received, lines 1309-1314 replenish the supply of unaccessed elements by sending a CONTINUE -- QUERY message and receiving the response. If additional elements are received, the first such one is copied into Output Host Variables by lines 1317-1319. Note that the status of Active Cursors is also updated in the same way as during the initiation of set oriented data access.
DESCRIPTION OF DATABASE INTERFACE FUNCTION FOR TERMINATING PROCESSING OF SET ORIENTED DATA ACCESSES
The Database Interface Function called in response to the execution of the database command which terminates processing of a set oriented data access ("CLOSE . . . " in SQL) must examine the Active Cursor Table 37 to determine whether the set oriented database command has been initiated. If not, an error is reported to the application program. If the Active Cursor Table 37 status is CLOSED, the Database Interface Function returns "end of query" to the application program. Otherwise, the Database Interface Function prepares and sends a CLOSE -- QUERY message to the remote DBMS. The agreed upon format of the CLOSE -- QUERY message contains:
1. the name of the application program package in which the command is located; and
2. the tag of the particular set oriented data access.
Upon receipt of a CLOSE -- QUERY message, the remote DBMS determines whether the indicated database command from the indicated package has been initiated and is still active. If so, the DBMS completes (terminates) processing of the indicated set oriented data access and responds favorably to the Database Interface Function. If not, the DBMS return an error response in an agreed upon format. The set oriented termination Database Interface Function removes the entry for the Set Oriented command from the Active Cursor Table.
FIG. 15 illustrates the Database Interface Function and Command Execution protocol for terminating set oriented data access. Line 1400 shows the invocation of "Set DIF close" with the parameters prepared during replacement of database commands. Lines 1401-1402 check whether processing has been initiated for the set specified by the package and tag parameters. Lines 1403-1406 send a CLOSE -- QUERY message and process its response if the "end of query" indication has not been received from the DBMS. Line 1407 removes the set specified by the package and tag parameters from Active Sets.
DESCRIPTION OF DATABASE INTERFACE FUNCTION FOR PROCESSING DYNAMIC DATABASE COMMANDS
The Database Interface Functions called to process the specification of a database command during application program execution transmit the text of the dynamically specified database command to the remote DBMS for either immediate or deferred execution. The Database Interface Function for immediate execution of a dynamically specified database command prepares and transmits an EXECUTE -- IMMEDIATE message, in an agreed upon format, to the remote DBMS. The elements of the EXECUTE -- IMMEDIATE message are:
1. the name of a package at the remote DBMS;
2. the database command tag assigned by the language Preprocessor program; and
3. the text of the database command to be dynamically defined and executed.
Upon receipt of an EXECUTE -- IMMEDIATE message the remote DBMS locates the package referenced by the message and confirms that it does not contain a (permanently) retained command with the same tag as the tag in the EXECUTE -- IMMEDIATE message. Then the received database command text is analyzed, optimized, and immediately executed. If errors are detected during this process, an error response message is returned to the Database Interface Function. The Database Interface Function for processing the specification of a dynamically specified database command for deferred execution prepares and transmits a PREPARE -- COMMAND message to the remote DBMS. The elements of the PREPARE -- COMMAND message are:
1. the name of a package at the remote DBMS;
2. the database command tag assigned by the language Preprocessor program; and
3. the text of the database command to be dynamically defined and executed.
Upon receipt of a PREPARE -- COMMAND message the remote DBMS locates the package referenced by the message and confirms that it does not contain a (permanently) retained command with the same tag as the tag in the PREPARE -- COMMAND message. Then the database command text from the PREPARE -- COMMAND message is analyzed, optimized, and (temporarily) retained as part of the package specified in the PREPARE -- COMMAND message. If no errors are detected, the remote DBMS prepares a reply message indicating successful execution. Otherwise, an error message will be returned to the Database Interface Function. The dynamically defined database command can subsequently be executed using the Database Interface Functions and messages for execution of Atomic or set oriented database commands.
FIG. 16 illustrates the Database Interface Function and Command Execution protocol for immediate execution of dynamically specified database commands. Line 1500 shows the invocation of "Dyn DIF immed" with the parameters prepared during replacement of database commands. Line 1501 obtains a copy of the database command to be executed. Lines 1502-1504 send an EXECUTE -- IMMEDIATE message to the remote DBMS and process the response.
FIG. 17 illustrates the Database Interface Function and Command Execution protocol for immediate execution of dynamically specified database commands. Line 1600 shows the invocation of "Dyn DIF defer" with the parameters prepared during replacement of database commands. Line 1601 obtains a copy of the database command to be prepared for deferred execution. Lines 1602-1604 send a PREPARE -- COMMAND message to the remote DBMS and process the response.
DESCRIPTION OF DATABASE INTERFACE FUNCTION FOR PROCESSING TRANSACTION DATABASE COMMANDS
The Database Interface Functions called to process transaction commit or abort database commands generate COMMIT -- transaction or ABORT -- transaction messages. These messages contain no additional elements. Upon receipt of a COMMIT -- transaction or ABORT -- transaction message, the remote DBMS commits or aborts the current database transaction. The remote DBMS replies to the Database Interface Function with a message, in an agreed upon format, indicating the outcome of the transaction database command.
THE DBMS COMMUNICATION AGENT
Introduction
This invention is dependent upon the agreed upon protocols for binding and database command execution. DBMS implementations, however, are usually greatly dependent on the computer environment in which they operate. This dependency is partially reflected in the precise ways in which the services of the DBMS are invoked for execution. An important aspect of this invention is that the communication protocols do not demand that new DBMS function be implemented. Rather, the invention is directed towards exploiting the full range of whatever function is available in already implemented DBMS systems. To this end, the invention relies on a component of the DBMS (or separate from the DBMS but running on the same computer) which is capable of communicating with the programs of the Application Access Agent and invoking the services of the DBMS proper to effect the execution of the functions associated with the messages of the binding and command execution protocols. This component is called the DBMS Communication Agent 52 (see FIG. 1).
The preferred implementation of the DBMS Communication Agent 52 is as an integrated component of the DBMS. Alternatively, the information content of the messages of the Binding and Command Execution protocols is sufficient to allow a separate implementation of the DBMS Communication Agent. A separated implementation of the DBMS Communication Agent can obtain needed DBMS services using the DBMS invocation mechanisms native to the computing environment of the DBMS computer.
DESCRIPTION OF THE DBMS COMMUNICATION AGENT
The DBMS Communication Agent 52 is the component of the DBMS computer with which the Binding program 38 and the Database Interface Functions 40 of the Application Access Agent 17 communicate. When communication is established by programs of the Application Access Agent, it is the DBMS Communication Agent to which the communication is directed.
Upon receipt of a message from the Application Access Agent, the DBMS Communication Agent 52 interprets the received message to determine what DBMS services are requested. The DBMS Communication Agent then requests the indicates services from the DBMS proper. This will, in general, involve making one or more invocations of DBMS services. For example, the EXECUTE -- ATOMIC -- COMMAND message requires the DBMS to execute a single retained Database Command, while the OPEN -- QUERY and CONTINUE -- QUERY messages require that the DBMS Communication Agent obtain and return multiple result set elements. The DBMS actions and services elicited by each of the messages of the binding and command execution protocols have been described in the preceding descriptions of the Bind program 18 and Database Interface Functions 40. The DBMS Communication Agent is also responsible for casting the DBMS responses to requested DBMS services into response messages to the Bind program and Database Interface Functions of the application program computer. This involves examining the execution results and indicators from the DBMS proper and fabricating the appropriate response messages. The relationship between the local results of DBMS service requests and the contents of the response messages has also been described in the descriptions of the Binding program and Database Interface Functions.
It is notable that the DBMS Communication Agent is, like the programs of the Application Access Agent, relatively insensitive to the detailed syntax and semantics of the Database Command language. Database Commands received via the Binding protocol and in Dynamic Database Command messages can be passed as received, or after some straightforward transformations, to the DBMS proper.
In summary, the DBMS Communication Agent is responsible for managing communication with the programs of the Application Access Agent. The DBMS Communication Agent 52, upon recognition and understanding of received messages, also oversees the invocation of the services of the DBMS proper to effect the execution of the database services requested by the Application Access Agent of the application program computer 10. In addition, the DBMS Communication Agent 52 interprets the results and indications from the DBMS proper in order to fabricate and transmit response messages to the Bind program and Database Interface Functions of the Application Access Agent of the Application Program computer.
SUMMARY OF THE METHOD OF THE INVENTION
Refer now to FIGS. 18-20 for a summary overview of the method of the invention. In step 100, the invention receives the application program with embedded database language commands. Preprocessor 18 scans the statements of the application program and, in step 102 recognizes and classifies the database language commands in the program. According to the best mode, the Preprocessor 18 classifies database commands into one of five categories, Host Variable declarations, Atomic commands, Set Oriented commands, Dynamic commands, or Transaction commands. In step 104, database language commands which have been recognized and classified are replaced in the application program by statements in the language of the application program. Otherwise, where appropriate, the classified database language commands are replaced with calls to the Database Interface Functions 40, the call referencing parameters including the name of the application program package, the command tag, input and output variables, and other parameters necessary to execution of the replaced command. In step 106, the Preprocessor 18 tags the commands and places them into the Bind file 20.
In step 108, the application program as modified by the Preprocessor 18 is compiled and linked to the Database Interface Functions 40. The position of this step in the procedure illustrated in FIGS. 18 and 19 can be moved to follow the Bind program steps.
The Bind program steps being in step 110 after compilation of the application program with determination of the address of the DBMS named as parameter to the Bind program. In step 112, communication with the named DBMS is established and BEGIN -- BIND processing is done during which the name identifying the application program package is communicated to the DBMS. In step 114, the tagged database language commands entered into the Bind file 20 by the Preprocessor 18 are sent one-by-one to the DBMS using a BIND -- DATABASE -- COMMAND process. When all commands have been sent, END -- BIND processing is undertaken in step 116 to terminate the Bind program processing. At this point, the application program is ready to execute and the database commands extracted from it have been sent to the DBMS where they have been retained in the application program's package.
At this point, with reference to FIG. 18, it is worth noting that the process comprising steps 100-108 can be completed at a remote unconnected site, at which time the Bind file 20 and linked application program 14a can be entered into a transportable storage medium such as an optical ROM, magnetic tape, floppy disk, or hard disk and installed in the computer system 10, whereupon the Bind steps 110-116 would be executed using the Application Access Agent of computer 10.
Continuing with the description of the procedure of the invention, the application program begins executing in step 118. The decision 120 is implicit in execution of the program and, for so long as no Database Interface Function call is encountered, the program continues to execute as exemplified by the negative exit from the decision 120 and returned to the decision 120 through the step 121.
When a Database Interface Function call is detected, the method of the program goes to step 124, where, using the name which identifies the application program package, the tag of the replaced database language command, and other command parameters including, but not limited to, input and output Host Variables, the appropriate one of the Database Interface Functions 40 is called. Exit 126 from procedure block 124 corresponds to an Atomic command call for which the corresponding Database Interface Function in step 127 constructs an EXECUTE -- ATOMIC -- COMMAND message and sends it to the DBMS with the name, tag, and other command parameters necessary for the DBMS to execute the command. Assuming successful execution of the command at the DBMS, the DBMS returns data which the Database Interface Function returns the application program as output Host Variables in step 129. From step 129, the program goes back to point B.
The exit 130 from the program block 124 represents the call corresponding to a Dynamic command for which a PREPARE -- COMMAND or EXECUTE -- IMMEDIATE message with the appropriate parameters is constructed and sent to the DBMS. Return is made to point B of the program from program step 131.
A Transaction command call is represented by the exit 135. As explained above, the appropriate Database Interface Function sends a message to the DBMS in step 136 requesting execution of a COMMIT or ABORT command. From here the procedure returns to program location B.
Last, the exit 138 represents a call corresponding to a Set Oriented command. As FIG. 20 illustrates, there are three possible branches, corresponding to the three possible Set Oriented Database Interface Functions. Branch 138a represents the initiation of a query by construction of a BEGIN -- QUERY message sent to the remote DBMS. Assuming a DBMS indicates acceptance of the message, it will retrieve the bound, tagged command and execute it by beginning a QUERY process. It will send result elements via message to the Database Interface Function 40 as laid out in step 141. From this point, the method returns to B in FIG. 19. The branch 138b represents the flow of result elements to the Database Interface Function which accumulates the element. For elements which have not been accessed by the application program, the positive exit from step 142 is taken and the elements are returned as Output Host Variables in step 147 to the application program. If there are no unaccessed retained variables, the negative exit is taken from the decision 142. The appropriate Database Interface Function 40 constructs a CONTINUE -- QUERY message, sends it, together with the appropriate parameters to the the DBMS and retains, in step 145, result elements received from the DBMS. The procedure then, in step 147, returns the elements as Output Host Variables to the application program. The termination of the QUERY is represented by branch 138c which enters the decision 150 to determine whether a "end of query" indication has been received from the DBMS. If so, the Database Interface Function processing is terminated for the query and the method returns to B in FIG. 19. The negative exit from the decision 150 corresponds to the termination of the query on the part of the Database Interface Function 40 by sending an END -- QUERY message with the appropriate parameters in step 151.
In FIG. 21, the Host Variable processing, which is a significant aspect of this invention, is illustrated. This aspect is intrinsic to the Preprocessor steps 102, 104, and 106 in FIG. 18. First, in table 200, every Host Variable declaration command is responded to in step 200 by entering the name and type of declared variable(s) into the Host Variable table 30 (FIG. 1). Now, when commands are placed into the Bind file 20, the Host Variable occurrences in each command are isolated (step 202) their types are determined from the Host Variable table 30 in step 206 and, in step 208, each Host Variable occurrence is replaced by a Host Variable marker with associated Host Variable types. This generic representation accompanies the commands in the Bind file 20 to the DBMS where they are bound. As shown in FIG. 1, each database command in which a Host Variable occurs exhibits, as a replacement, a marker denoting the occurrence and the type. This is shown by the command 62 stored in the package "NAME" 60 in the catalog 63. It is asserted that the DBMS 54 uses the marker to render the Host Variable into a form which is native to the DBMS, thereby supporting execution of the bound command.
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. Accordingly, the scope of protection of this invention is limited only by the following claims and their equivalents. | Application programs which are developed and scheduled within a first computing system environment are permitted to access relational data registered at a remote database management system (DBMS) operating in a second computing environment dissimilar to the first computing environment. Access to data through the DBMS from an application execution site remote from the DBMS is supported by a process, logically subordinate to the application program which maps application program data access requests to the DBMS. | 8 |
FIELD OF THE INVENTION
[0001] The present invention relates to a device for 3D characteristic vertebral feature identification, a medical imaging system, a method for 3D characteristic vertebral feature identification using 3D volume data, a computer program element, and a computer-readable medium.
BACKGROUND OF THE INVENTION
[0002] When performing a minimally invasive spinal intervention, a popular imaging modality is intra-operative fluoroscopy. The field of view of a fluoroscopy imager is quite small. Therefore, such an imager can simultaneously display only a few spinal vertebrae of a long spinal column, and identifying contiguous vertebrae is difficult, because such contiguous vertebrae are similar in shape. Displaying the entire spinal column is not feasible. In addition, the 2D fluoroscopy only shows 2D projections, and it is difficult to assess 3D differences from such projections. Therefore, a burden is placed upon a medical professional performing a minimally invasive spinal intervention, because they must ensure that the correct vertebral level is being treated.
[0003] EP 2 756 804 describes a system for identifying a part of a spine. Such systems can be further improved. U.S. Pat. No. 8,509,502 describes a system configured to identify a plurality of vertebrae and label each vertebra based on a 3D spinal model data and an analysis of 3D vertebral shape difference.
SUMMARY OF THE INVENTION
[0004] It would be advantageous to have an improved technique for providing 3D characteristic vertebral feature identification.
[0005] Towards this end, a first aspect of the invention provides a device for 3D characteristic vertebral feature identification, comprising an input unit, a processing unit, and an output unit.
[0006] The input unit is configured to provide processed 3D volume information representing a portion of a spinal column, wherein the processed 3D volume information is computed from a plurality of images obtained through the spinal column, and is acquired along a plurality of acquisition directions.
[0007] The processing unit is configured to generate 3D spinal model data derived from the processed 3D volume information, to select first vertebra information and second vertebra information in the 3D spinal model data, and to compute 3D characteristic vertebral feature information of the first vertebra by computing a 3D vertebral shape difference between the first vertebra information and the second vertebra information in the spinal model data.
[0008] The output unit is configured to output the 3D characteristic vertebral feature information. In the following specification, the term “outputting” means that the information in question is made available internally to the system for e.g. subsequent processing, and/or externally to a user e.g. via a display.
[0009] According to a second aspect of the invention, a method for 3D characteristic vertebral feature identification using processed 3D volume information is provided. The method comprises the following steps:
[0000] a) providing processed 3D volume information representing a portion of a spinal column, wherein the 3D volume data is computed from a plurality of images obtained through the spinal column, and is acquired along a plurality of acquisition directions;
b) generating 3D spinal model data derived from the processed 3D volume information;
c) selecting first vertebra information and second vertebra information in the 3D spinal model data;
d) computing 3D characteristic vertebral feature information of the first vertebra by computing a 3D vertebral shape difference between the first vertebra information and the second vertebra information in the spinal model data; and
e) outputting the 3D characteristic vertebral feature information.
[0010] According to a third aspect of the invention, there is provided a medical imaging system, comprising a medical imaging acquisition arrangement, and an image processing arrangement.
[0011] The image processing arrangement is provided as a device as previously described.
[0012] According to a fourth aspect of the invention, there is provided a computer program element for controlling a device for displaying medical images acquired from a target as previously described, which, when being executed by a processing unit, is adapted to perform the method steps previously described.
[0013] According to a fifth aspect of the invention, a computer-readable medium having stored the computer program previously described is provided.
[0014] The computation of 3D characteristic vertebral feature information of at least a first vertebra enables pre-interventional data, such as CT data, to be used for the automatic determination of patient-specific characteristic features of vertebrae, facilitating automatic vertebral level determination when only a portion of a spinal column is visible. The automatic determination of such patient-specific characteristic features allows the identification of specific vertebral levels, even when a full spinal column is not visible in a fluoroscopy image.
[0015] The automatic determination of three-dimensional patient-specific characteristic features from pre-interventional data additionally permits the identification of an improved viewing angle for the identification of a certain vertebral level during an X-ray fluoroscopy operation. Therefore, an improved viewing direction can also be provided. The use of the improved viewing direction as a given projection view of 2D medical imaging equipment, such as X-ray fluoroscopy equipment, enables a viewer, such as a medical professional, to perceive as many characteristic vertebral features as possible. The fact that such medical imaging equipment is positioned in an optimal view direction allows for more reliable vertebral feature identification, because more patient-specific vertebral features are visible to a medical professional in the 2D view.
[0016] In the following specification, the term “processed 3D volume information” means 3D image data defining the internal arrangement of an imaged volume in the form of voxels, for example. The processed 3D volume data could originate from, for example, a CT scanner, an MRI scanner, or a C-arm imaging system. Reconstruction algorithms, which provide processed 3D volume information from a plurality of images obtained through a patient, and acquired along a plurality of acquisition directions, are known to the person skilled in the art.
[0017] In the following specification, the term “3D spinal model data” means data that has been post-processed from the processed 3D volume data, to provide outline, or volume information of a spinal column, or a portion of a spinal column, in the processed 3D volume data.
[0018] In the following specification, the term “vertebra information” means 3D spinal model data defining a specific vertebra of the spine, contained in the processed 3D volume information. Such vertebra information may be selected automatically from the 3D spinal model data, by image recognition algorithms. Alternatively, the vertebra information may be highlighted manually by a user using a workstation and graphical user interface.
[0019] In the following specification, the term “3D vertebral shape difference” means that an element of the 3D spinal model data has a voxel arrangement, which is notably different to that of another neighbouring vertebra of the patient, in the context of the rest of the 3D spinal model data. Typically, when comparing two vertebrae, the shape difference will be seen when one vertebra has an extra protrusion, caused by a spondylophyte, a fracture, or a surgical screw or an implant.
[0020] In other words, during a minimally invasive spinal intervention, it is important to identify with confidence at least one spinal vertebra in the fluoroscopy field of view. This does not, necessarily, need to be the vertebra being treated, because provided one vertebral level is identified in the field of view of the fluoroscopy equipment, the others can be identified implicitly by counting up or down. Pre-interventional data from a CT or MRI scanner is used to identify patient-specific features of at least one spinal vertebra. These features are accepted as characteristic features of the vertebra. The characteristic features allow the identification of unique vertebral segments. Patient-specific vertebral features such as spondylophytes, fractures, missing bone pieces or surgical screws and implants are three-dimensional, and therefore are best characterized using a three-dimensional shape difference. An optimal viewing direction can be computed for at least one vertebra identified as having a characteristic feature or more vertebrae having each a identified characteristic feature. The computation can be performed off line, before or during the intervention. During the intervention, the computed optimal viewing direction that may be selected among the other ones may depend on a target vertebral level information.
[0021] These and other aspects of the invention will become apparent from, and are elucidated, with reference to the embodiments described hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Exemplary embodiments of the invention will be described with reference to the following drawings:
[0023] FIG. 1 shows an example of a method according to an aspect of the invention.
[0024] FIG. 2 shows a segment of spinal column.
[0025] FIG. 3 shows an exemplary spinal 3D characteristic feature identification process.
[0026] FIG. 4 shows an exemplary identification of an optimal view direction.
[0027] FIG. 5 shows an exemplary practical result of optimal view direction identification.
[0028] FIG. 6 shows a device for 3D characteristic vertebral feature identification according to an aspect of the invention.
[0029] FIG. 7 shows an example of a medical imaging system according to an aspect of the invention.
DETAILED DESCRIPTION OF EMBODIMENTS
[0030] When performing minimally invasive spinal interventions, it can be difficult to identify the correct vertebral level of a spinal column. Usually, the imaging modality is intra-operative fluoroscopy, and this modality has a restricted field of view. Identifying neighbouring (contiguous) vertebrae is difficult, because such contiguous vertebrae are very similar in shape to each other. Displaying the entire spinal column is not feasible. In addition, the 2D fluoroscopy only shows 2D projections, and it is difficult to assess 3D differences from such projections. Therefore, only a few vertebrae of the spinal column are visible at one time. Identification of a specific vertebral level can be misleading if a medical professional performing the spinal intervention miscalculates the number of vertebral levels. Such a miscalculation could originate from confusion, over which vertebral level appears at the boundary of the field of view of the fluoroscopy imager's field of view. Vertebral levels are labelled sequentially, as is known in the art, as T 1 , T 2 , T 3 , et cetera.
[0031] FIG. 2 illustrates such a situation. A spinal column 12 comprising seven vertebrae is shown. The vertebrae are labelled T 1 to T 7 . An effective field of view 10 of a fluoroscopy imager is shown by a dotted boundary. There is a region 14 of vertebrae within the field of view, such as vertebrae T 2 , T 3 , T 4 , T 5 . Vertebrae T 1 and T 2 fall in an upper excluded area 16 of the fluoroscopy imager's field of view. T 7 is excluded from a bottom of the fluoroscopy imager's field of view 18 . If a minimally-invasive surgical intervention was performed on vertebra T 4 , and the medical professional had no prior knowledge of the positioning of the fluoroscopy field of view 10 with respect to the rest of the spinal column, it would be easy for the medical professional to perform, incorrectly, the intervention in vertebra T 3 , or vertebra T 5 . Thus, for example, it could be difficult to assess whether, given sequence T 4 -T 5 -T 6 , one is looking at sequence T 3 -T 4 -T 5 , T 4 -T 5 -T 6 , or T 5 -T 6 -T 7 .
[0032] FIG. 1 illustrates that, according to an aspect of the invention, a method 20 for 3D characteristic vertebral feature identification using processed 3D volume information is provided, comprising the following steps:
[0000] a) providing 22 processed 3D volume information representing a portion of a spinal column, wherein the processed 3D volume information is computed from a plurality of images obtained through the spinal column, and is acquired along a plurality of acquisition directions;
b) generating 24 3D spinal model data derived from the processed 3D volume information;
c) selecting 25 first vertebra information and second vertebra information in the 3D spinal model data;
d) computing 26 3D characteristic vertebral feature information of the first vertebra by computing a 3D vertebral shape difference between the first vertebra information and the second vertebra information in the 3D spinal model data; and
e) outputting 27 the 3D characteristic vertebral feature information.
[0033] Accordingly, the automatic determination of 3D patient-specific characteristic features for vertebral level identification is possible, using pre-interventional volume data obtained from a CT scanner, or an MRI scanner. This additionally allows the identification of an optimal viewing angle for vertebral level identification in medical imaging, because the pre-interventional volume data may be used to calculate the occlusion of the derived 3D characteristic vertebral feature information by a spine, for example, at various forward-projection angles.
[0034] FIG. 3 illustrates an approach to characterizing characteristic vertebral feature information using 3D shape comparison.
[0035] In FIG. 3A there are shown three segments of a section of a spinal column T 4 , T 5 , and T 6 . This information has been acquired from processed 3D volume information, for example from a CT scanner or an MRI scanner. FIG. 3A effectively illustrates 3D spinal model data that has been derived from the processed 3D volume information by segmenting the processed 3D volume data. Shown in the section of a spinal column 28 is vertebral level T 4 , vertebral level T 5 and vertebral level T 6 . Vertebral levels T 4 and T 5 represent relatively normal vertebrae. Vertebral level T 6 , however, has a projection 30 on its left side known as a spondylophyte. Spondylosis is an osteoarthritic degeneration of the vertebrae and the spine characterized by abnormal bony growths. Such features can be useful when characterizing individual vertebral segments.
[0036] FIG. 3B illustrates the 3D characteristic feature detection using shape registration with neighbouring vertebrae. A letter 8 denotes the function of performing the computation of shape differences.
[0037] There are various ways to identify the shape difference between two arbitrary regions of voxels.
[0038] Preferably, surface representation in 3D spinal model data is most commonly done using triangular surface meshes. Therefore, surface registration between the first and second vertebra information is performed using, for example, an iterative closest point (ICP) algorithm. After surface registration, the surface distances are calculated by finding, for each vertex on the first vertebral information, the closest point to that point on the surface of the second vertebral information. Features are then found by thresholding the distances.
[0039] According to an embodiment of the invention, an example of the method as described previously is provided, wherein in step d), the computing of the 3D characteristic vertebral feature information further comprises:
[0000] d6) performing a shape registration between the first vertebra information and the second vertebra information;
d7) computing a 3D shape difference between the registered first vertebra information and second vertebra information; and
d8) identifying a region in the first vertebra information using a computed shape difference as the 3D shape difference.
[0040] According to an embodiment, in step d6), an iterative closest point (ICP) algorithm is used to perform the shape registration.
[0041] According to an embodiment, in step d8), the region in the first vertebra information is identified by thresholding surface differences between the first vertebra information and the second vertebra information.
[0042] According to an embodiment of the invention, an example of the method as described previously is provided, wherein in step d8), the step of identifying a region in the first vertebra information comprises identifying the 3D shape difference between the registered first vertebra information and second vertebra information, which is greater than a vertebral difference threshold.
[0043] Therefore, it is possible to prevent the mis-identification of vertebral differences, which are due to natural variations in the bone surface, for example, and to only detect vertebral differences, which are significant to a medical professional.
[0044] In an alternative embodiment, the 3D vertebral shape difference between the first vertebra information and the second vertebra information is computed by superimposing upon pre-calculated centre-lines of the first and second vertebra information, and a direct subtraction of the first vertebra information, representing a first vertebral level from the second vertebra information, representing a second vertebral level, could be performed in 3D. The remaining voxels would be the 3D characteristic features.
[0045] In another alternative embodiment, a shape registration of the first vertebra information and the second vertebra information is performed. For example, a registration could be performed between T 6 and T 5 , and/or T 6 and T 4 . This shape registration may be extended to a larger number of vertebral segments.
[0046] As illustrated, using a technique as discussed above, or similar, a first shape difference between a first vertebral level T 6 and a second vertebral level T 5 is derived. Then, the shape difference between the first vertebral level T 6 and a third vertebral level T 4 is derived.
[0047] According to an embodiment of the invention, the derivation of the shape difference is limited to vertebrae present in a proposed 2D fluoroscopy field of view.
[0048] FIG. 3C illustrates vertebra T 6 with its 3D characteristic vertebral feature information 32 isolated. Because the 3D characteristic vertebral feature information is a subset of the voxels of the processed 3D volume information representing a portion of the spinal column, the 3D characteristic vertebral feature information may be viewed in different directions. In addition, the voxels constituting the 3D characteristic vertebral feature information are referenced to the geometric frame of reference of the original processed 3D volume information, enabling the production of forward projections through only the extracted the 3D characteristic vertebral feature information, or alternatively the production of forward projections of the 3D characteristic vertebral feature information, which are occluded by portions of the spinal column.
[0049] According to an embodiment of the invention, a method is provided as described previously, wherein the 3D characteristic vertebral feature information represents an anatomical feature selected from the group of: a first rib pair, a last rib pair, a sacrum, an atlas, a spondylophyte, a fracture, or an implant.
[0050] Therefore, frequently occurring spinal deformations can be used to identify 3D characteristic vertebral feature information.
[0051] Although the foregoing embodiments have discussed the acquisition of 3D characteristic vertebral feature information of a first vertebra only, it will be understood that the algorithm can be extended to compute, alone, or in combination, 3D characteristic vertebral feature information of at least a second vertebra, and/or a third vertebra, and/or a fourth vertebra, and/or a fifth vertebra, or all vertebrae present in a spinal column.
[0052] According to an embodiment of the invention, the viewing position of a 2D intra-operative fluoroscopy device along the spine of a patient is provided. Then, 3D characteristic feature information may be computed for vertebrae, which can be best seen in the viewing plane of the 2D intra-operative fluoroscopy device, at the viewing position.
[0053] The viewing position is provided as a point in the 3D frame of reference of the original processed 3D volume information. For example, the viewing position is provided as a horizontal displacement along the spine, at a certain distance from the spine, and an angular deviation from the spine.
[0054] After the identification of the 3D characteristic vertebral feature information, a series of voxel regions will be available. These voxel regions, representing characteristic features of a spinal column, will self-evidently be referenced to the geometric datum used for acquiring the processed 3D volume information. Therefore, using reconstruction techniques, an optimal patient viewing direction of the 3D vertebral features can be calculated, which optimizes the visibility of the 3D characteristic vertebral features in a 2D projection.
[0055] According to an embodiment of the invention, forward projections through the voxels representing only the 3D characteristic vertebral features are performed.
[0056] According to an embodiment of the invention, forward projections through the voxels representing the 3D characteristic vertebral features, and through the voxels representing the spinal column are performed. According to an embodiment of the invention, a method is provided as discussed previously, wherein step a) further comprises:
[0000] a1) providing target vertebral level information;
wherein step d) further comprises:
d1) determining a patient viewing direction using the 3D characteristic vertebral feature information and the target vertebral level information, wherein the patient viewing direction is determined by searching for a viewing direction, which optimizes a 3D characteristic vertebral feature visibility metric; and
wherein step e) further comprises:
e1) outputting the patient viewing direction.
[0057] According to this embodiment, the visibility of the characteristic spinal features (represented by the 3D characteristic vertebral feature information) in a 2D projection can be optimized during an intra-operative fluoroscopic image intervention.
[0058] In the previously described embodiments, the provision of target vertebral level information comprises the identification by a medical professional of a vertebral level of a patient's spinal column, which will be treated in a minimally invasive spinal intervention. For example, in FIG. 3 , the level T 5 would be selected and input as the target vertebral level information using a computer interface, for example.
[0059] The 3D characteristic vertebral feature visibility metric provides an indication of how a certain viewing direction affects the visibility of the 3D characteristic vertebral feature information. There are many ways to calculate such a metric.
[0060] According to an embodiment of the invention, the 3D characteristic vertebral feature visibility metric is calculated by performing a plurality of forward projections through voxels representing the 3D characteristic vertebral feature information from a plurality of directions around voxel clusters.
[0061] The forward projection direction, which results in the greatest area in a 2D projection resulting from a forward projection through the 3D characteristic vertebral feature information, is the viewing direction, which optimizes a 3D characteristic vertebral feature visibility metric.
[0062] Due to the projective nature of fluoroscopy, there will be viewing directions, in which certain features can be identified more easily than others. Given a target vertebral level, characteristic features in close proximity can be selected. Using the previously described method, a viewing direction is determined such that the maximum number of these features can be identified, or that one feature is optimally viewable. In addition to shape characteristics, superimposed surrounding anatomy can also be taken into account for optimum view angle determination. After determining the characteristic feature for identification, it also need to be considered that the features are only visible in certain viewing directions.
[0063] In order to determine features that can easily be seen in a fluoroscopic projection, the range of viewing directions, for which the characteristic edges of the features are parallel are first determined. Then, simulated projection images can be calculated from the pre-operative data, such as CT data. Standard algorithms for projection are used in the step. Then, an analysis is made of the local neighbourhood around the feature, by calculating the variability of grey values within a small region of interest around the feature, or by analyzing the gradients at the feature position to detect whether or not the landmark is located on an edge. Then, features that can clearly be seen in the image can be automatically selected. The optimal view plane is then chosen such that it contains the maximum number of clearly visible features. The optimal view plane may be selected during the intervention while the range of viewing directions may be computed before or during the intervention.
[0064] According to an embodiment of the invention, in step d1) the 3D spinal model data is used to occlude the 3D characteristic vertebral feature information.
[0065] Therefore, the forward projections, which are calculated when determining the patient viewing direction, produce 2D areas in the projected view plane, which result firstly from rays projected through 3D characteristic vertebral feature information, and secondly from rays projected through 3D spinal model data. This ensures that the 3D characteristic vertebral feature visibility metric for each forward projection direction, and therefore the patient viewing direction eventually chosen, is that which enables the most characteristic features to be seen, even in the presence of the spine.
[0066] According to an embodiment of the invention, the outputting of the patient viewing direction may be in a standard format, such as a solid angle with respect to the datum of the processed 3D volume data acquired, for example, from a CT scanner.
[0067] According to an embodiment of the invention, this geometrical information is used to align equipment to provide an optimal viewing direction of the characteristic vertebral features.
[0068] FIG. 4 illustrates the above-described process. A geometrical reference cube 40 containing display voxels is illustrated with a segment of spinal column inside. The spinal column has first and second characteristic features illustrated by a triangle 44 , and by a circle 46 . Although in this purely exemplary presentation, two characteristic vertebral features are shown on different vertebral levels, it will be understood that the algorithm would work with only one 3D characteristic vertebral feature on one vertebral level, such as only the triangle 44 .
[0069] The algorithm produces forward projections at a range of different forward projection angles through a 3D spinal model data 42 . The forward projection angles are illustrated from points or positions 41 , 43 , and 45 .
[0070] An exemplary first 2D screen 47 shows the effect of a forward projection from the position 41 . It can be seen that the spinal column section is viewed from the side, and the characteristic features 44 and 46 are entirely occluded by the spine itself. Therefore, this would not be a good candidate viewing direction.
[0071] An exemplary second 2D screen 48 shows a forward projection of the characteristic features from the position 43 . It can be seen that the triangular characteristic feature 44 is present, but this occludes the characteristic feature 46 .
[0072] An exemplary third 2D screen 49 shows the view of the 3D characteristic vertebral feature information from the position 45 . In this screen, the sides of both characteristic features 44 and 46 can be seen with ease, and this is selected as the patient viewing direction, because the 3D characteristic vertebral feature visibility metric will be optimal in this position.
[0073] FIG. 5 illustrates a clinical example where defining the correct viewing direction is important.
[0074] In FIG. 5A , a projection from processed 3D information is shown 52 . A ringed area 53 shows a spondylophyte in the processed 3D information, which could be used for identification, because other vertebrae in the processed 3D information do not have such a feature.
[0075] In FIG. 5B , a fluoroscopic projection of the spinal column imaged in the processed 3D information of FIG. 5A is shown.
[0076] The fluoroscopic projection has been taken from a viewing direction (with respect to the spine), in which the spondylophyte 53 is occluded by the remainder of the spinal column. Therefore, the spondylophyte is not visible to the medical professional performing the intervention. This means that a surgical professional aiming to identify a target vertebral level of the spine using the spondylophyte from the fluoroscopic projection angle of B would have difficulty identifying the correct target vertebral level.
[0077] FIG. 5C illustrates a fluoroscopic projection 56 taken from a viewing direction, which clearly shows the spondylophyte at 58 , as identified by the algorithm.
[0078] Therefore, the target vertebral level can easily be identified by a medical professional from the fluoroscopy image using the spondylophyte.
[0079] According to an embodiment of the invention, a method is provided as described previously, wherein step b) further comprises:
[0000] b1) providing 3D superimposed anatomy information from the processed 3D volume information; and
wherein step d) further comprises:
d2) calculating an occlusion metric of the 3D characteristic vertebral feature information for a plurality of synthetic viewing directions of the 3D spinal model data, wherein an occlusion is caused by an anatomical feature in the 3D superimposed anatomy information; and
d3) deriving the 3D characteristic vertebral feature visibility metric based on the occlusion metric of the 3D characteristic vertebral feature information.
[0080] Different organs inside the patient such as the liver, the heart, the lungs, and the pancreas, have different X-ray translucencies, and may affect the identification of characteristic vertebral features during a 2D fluoroscopy.
[0081] Therefore, in this embodiment, 3D superimposed anatomy information is derived from the processed 3D volume information obtained, for example from a CT scan. The occlusion of the internal organs around the spinal column is taken into account when calculating the 3D characteristic vertebral feature visibility metric. It could be the case that a patient viewing direction, which provides the optimal 3D characteristic vertebral feature visibility without taking into account the patient's anatomy might not be so optimal when taking into account the position of the liver, the lungs and other organs. It will be appreciated that the position of the patient's internal organs can easily be derived from the processed 3D volume information and used in forward projection reconstructions.
[0082] According to an embodiment of the invention, a method is provided as discussed previously, wherein step i) further comprises:
[0000] e2) aligning a patient imaging system based on the determined patient viewing direction.
[0083] Patient imaging systems are provided on electrically-positionable frames, with electro-mechanical drives, which can be interfaced to a control system, such as a computer control system. Provided a geographical datum of the processed 3D volume information, the patient imaging system, and the current alignment of a patient are accounted for, it is possible for a patient imaging system to be aligned with respect to a patient, using the determined patient viewing direction.
[0084] Therefore, a patient imaging system may be automatically aligned to provide the optimal imaging direction based on 3D volume data representing a portion of a spinal column, providing a more convenient and accurate self-alignable item of medical imaging equipment.
[0085] According to an embodiment of the invention, the patient imaging system is an electro-mechanically alignable fluoroscopy system.
[0086] The optimum viewing angle (related to the optimal view plane) is communicated to the user (or directly to the imaging system). Fluoroscopy projections are made using that viewing angle. The pre-interventional data is displayed to the user as volumetric, or as a slice display, or as a simulated projection, with the identified characteristic landmarks and the target vertebral level indicated.
[0087] According to an embodiment of the invention, a method is provided as discussed previously, wherein step a) further comprises:
[0000] a2) providing processed 2D live intervention data, representing a portion of a spinal column during a surgical intervention;
wherein step d) further comprises:
d4) registering the 2D live intervention image data to the 3D characteristic vertebral feature data; and
d5) providing a 2D augmented intervention image by projecting the 3D characteristic vertebral feature data onto the 2D live intervention image from the patient viewing direction; and
wherein step e) further comprises:
e3) displaying the augmented intervention image.
[0088] Therefore, the live 2D fluoroscopy data is augmented with a forward projection of the 3D characteristic vertebral feature data at the same angle as the patient viewing direction used with the fluoroscopy equipment during the intervention.
[0089] Because the 2D live intervention image data will be aligned in the same viewing plane as the forward projection of the 3D characteristic vertebral feature data; it is possible to highlight, or to “ghost” the characteristic vertebral feature data into the 2D live intervention image data view. This ensures that during a minimally invasive intervention, the target vertebral level is correctly identified.
[0090] The augmented live intervention image provides enhanced feedback about the location of characteristic features on the spine. Therefore, the user can identify the 3D characteristic features during a live fluoroscopy, and then as a reference determines the appropriate target vertebral level for treatment.
[0091] According to an embodiment of the invention, a device 60 for 3D characteristic vertebral feature identification is provided. The device comprises an input unit 62 , a processing unit 64 , and an output unit 66
[0092] The input unit 62 is configured to provide processed 3D volume information representing a portion of a spinal column, wherein the processed 3D volume information is computed from a plurality of images obtained through the spinal column, and is acquired along a plurality of acquisition directions.
[0093] The processing unit 64 is configured to generate 3D spinal model data derived from the processed 3D volume information, to select first vertebra information and second vertebra information in the 3D spinal model data, to compute 3D characteristic vertebral feature information of the first vertebra by computing a 3D vertebra shape difference between the first vertebra information and the second vertebra information in the 3D spinal model data.
[0094] The output unit 66 is configured to output the 3D characteristic vertebral feature information.
[0095] The device 60 may be implemented as a software programme executing on a computer processor, with input and output interface circuitry. Alternatively, processing may be performed by a digital signal processor, an FPGA, an ASIC, or combinations of these.
[0096] According to an embodiment of the invention, an example of the device 60 is provided as discussed previously, wherein the input unit 62 is further configured to provide target vertebral level information. The processing unit 64 is further configured to determine a patient viewing direction using the 3D characteristic vertebral feature information and the target vertebral level information, wherein the patient viewing direction is determined by searching for a viewing direction, which optimizes a 3D characteristic vertebral feature visibility metric. The output unit 66 is further configured to output the patient viewing direction.
[0097] According to an embodiment of the invention, an example of the device 60 is provided according to the previous description, wherein the processing unit 64 is further configured to generate 3D superimposed anatomy information from the processed 3D volume information, to calculate an occlusion metric of the 3D vertebral shape difference for a plurality of synthetic viewing directions of the 3D spinal model data, wherein an occlusion is caused by an anatomical feature in the 3D superimposed anatomy information, and to derive the 3D characteristic vertebral feature visibility metric based on the occlusion metric of the 3D characteristic vertebral feature information.
[0098] According to an embodiment of the invention, an example of the device 60 is provided according to the previous description, wherein the output unit 66 is further configured to align a medical imaging acquisition arrangement based on the determined patient viewing direction.
[0099] According to an embodiment of the invention, an example of the device 60 is provided according to the previous description, wherein the input unit 62 is further configured to provide processed 2D live intervention image data, representing a portion of a spinal column during a surgical intervention. The processing unit 64 is further configured to register the 2D live intervention image data to the 3D characteristic vertebral feature data, to provide a 2D augmented intervention image by projecting the 3D characteristic vertebral feature data onto the 2D live intervention image data from the patient viewing direction. The output unit 66 is further configured to display the augmented intervention image.
[0100] According to an embodiment of the invention, an example of the device 60 is provided as described previously, wherein the processing unit 64 is further configured to segment the processed 3D volume information to provide 3D spinal model data from the processed 3D volume information.
[0101] According to an embodiment of the invention, an example of the device 60 is provided as described previously, wherein the processing unit 64 is further configured to compute the 3D characteristic vertebral feature information by performing a shape registration between the first vertebra information and the second vertebra information, by computing a shape difference between the registered first vertebra information and second vertebra information, and by identifying a region in the first vertebra information using the computed shape difference as the 3D shape difference.
[0102] According to an embodiment of the invention, an example of the device 60 is provided according to the previous description, wherein the processing unit 64 is configured to identify the 3D vertebral shape difference between the registered first vertebra information and second vertebra information, which is greater than a vertebral difference threshold.
[0103] According to an aspect of the invention, a medical imaging system 70 is provided. The medical imaging system 70 comprises a medical imaging acquisition arrangement 72 and an image processing arrangement 74 .
[0104] The image processing arrangement 72 is provided as a device as previously described.
[0105] According to an embodiment of this aspect, the medical imaging system 70 is provided as described previously, wherein the medical imaging acquisition arrangement 72 further comprises an imager alignment mechanism 76 . The image processing arrangement 74 is provided as a device according to the previous description, and the imager alignment mechanism 76 is configured to be aligned based on the patient viewing direction output from the image processing arrangement 74 . The imager alignment mechanism comprises electro-mechanical drives controlling an azimuth 80 and an elevation 78 of the fluoroscopic imager 72 .
[0106] According to this aspect of the invention, it is possible to align automatically a medical imaging system, which for example may include a 2D fluoroscopy imager, according to characteristic features on input 3D volume data acquired from a pre-operative CT scan.
[0107] According to an embodiment of the invention, a medical professional may select certain characteristic features in the 3D volume data, and the medical imaging acquisition arrangement may be aligned, based only on the optimal viewing direction for the selected features.
[0108] Therefore, when performing a minimally invasive spinal intervention, it is possible to arrange a medical imaging acquisition arrangement at an optimal angle, in a convenient manner, to ensure that mis-identification of target vertebral levels does not occur.
[0109] According to an embodiment of the invention, the image processing arrangement 74 further comprises a pre-operative processing application, executed on a computer. A user may use an interface of the a pre-operative processing application to position a “field of view” frame in a user interface of the application, corresponding to the field of view of the fluoroscopy equipment, over a displayed relevant section of spinal column, to pre-compute the 3D characteristic features.
[0110] According to an embodiment of the invention, the image processing arrangement 74 further comprises alignment monitoring means connected to the image processing arrangement 74 . The alignment monitoring means is configured to monitor a change in the alignment of the medical imaging acquisition arrangement 72 . When a change in the alignment of the medical imaging acquisition arrangement 72 , relative to the patient, is detected, the image processing arrangement 74 recomputes the 3D characteristic vertebral feature information.
[0111] Therefore, if the a medical imaging acquisition arrangement 72 is translated horizontally along the patient, or around the patient, image processing arrangement 74 can display an updated enhanced 2D fluoroscopy view, showing the expected 3D vertebral characteristic features, which will be visible in the changed field of view.
[0112] According to an aspect of the invention, a computer program element for controlling a device for displaying medical images acquired from a target is provided according to the previous description. The computer program element, when being executed by a processing unit, is adapted to perform the method steps as discussed above.
[0113] According to an aspect of the invention, a computer-readable medium having stored the program as described above is provided.
[0114] A computer program element might therefore be stored on a computer unit, which might also be part of an embodiment of the present invention. This computing unit may be adapted to perform or induce performance of the steps of the method described above.
[0115] Moreover, it may be adapted to operate the components of the above described apparatus. The computing unit can be adapted to operate automatically and/or to execute the orders of a user. A computer program may be loaded into a working memory of a data processor. The data processor may thus be equipped to carry out the method of the invention.
[0116] This exemplary embodiment of the invention covers both the computer program that has the invention installed from the beginning, and a computer program that by means of an update turns an existing program into a program that uses the invention.
[0117] A computer program may be stored and/or distributed on a suitable medium, such as optical storage media or a solid state medium supplied together with, or as a part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems.
[0118] However, the computer program may also be presented over a network like the World Wide Web and can be downloaded into the working memory of a data processor from such a network. According to a further exemplary embodiment of the present invention, a medium for making a computer program element available for downloading is provided, which computer program element is arranged to perform a method according to one of the previously described embodiments of the invention.
[0119] It should to be noted that embodiments of the invention are described with reference to different subject-matters. In particular, some embodiments are described with reference to method-type claims, whereas other embodiments are described with reference to the device-type claims. However, a person skilled in the art will gather from the above, and the following description that, unless otherwise notified, in addition to any combination of features belonging to one type of subject-matter, also any other combination between features relating to different subject-matters is considered to be disclosed with this application.
[0120] All features can be combined to provide a synergetic effect that is more than the simple summation of the features.
[0121] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary, and not restrictive. The invention is not limited to the disclosed embodiments.
[0122] Other variations to the disclosed embodiments can be understood, and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the dependent claims.
[0123] In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single processor, or other unit, may fulfil the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope. | Minimally-invasive spinal inventions are often performed using fluoroscopic imaging methods, which can give a real-time impression of the location of a surgical instrument, at the expense of a small field of view. When operating on a spinal column, a small field of view can be a problem, because a medical professional is left with no reference vertebra in the fluoroscopy image, from which to identify a vertebra, which is the subject of the intervention. Identifying contiguous vertebrae is difficult because such contiguous vertebrae are similar in shape. However, characteristic features, which differentiate one vertebra from other vertebra, and which are visible in the fluoroscopic view, may be used to provide a reference. | 0 |
BACKGROUND OF THE INVENTION
This invention concerns wastewater treatment, and in particular a modification of the manner in which settled sludge is withdrawn from the bottom of a clarifier tank.
In a conventional wastewater treatment plant, wastewater is fed into one or more clarifier tanks, where solids are settled to the bottom of the tank, gathered toward the center of the sloping tank bottom by the rake arms of a rotating rake, then discharged out of the tank through a bottom exit pipe installed beneath the concrete floor surface. This type of installation can present problems, such as corrosion, clogging or failure of a pipe beneath the surface, lack of such an exit pipe in a tank to be converted to a clarifier tank, servicing of the pipe, need for increase in outflow capacity, etc. Replacement of such an underground pipe is difficult and very costly.
U.S. Pat. No. 5,340,485 showed a somewhat different system for collection of settled sludge from the floor of a clarifier. The patent shows a collection tube positioned radially outwardly from the center column, for drawing the sludge to an elevated position initially, then into the center column and down through an exit pipe. The withdrawal pipe in that system was located beneath the flow of the clarifier. A pump was positioned to withdraw the sludge. In one embodiment the sludge is drawn up almost to the liquid level in the tank, to a sludge collection box, into the center column and a vertical discharge pipe, then back down below the clarifier floor to an exit pipe. The patent also shows, in FIG. 5 , a manifold device for use where the sludge enters the vertical discharge pipe, and a device similar to that manifold device can be used in the current invention, although in a different way.
It is an object of the invention to withdraw settled sludge from the floor of a clarifier into the center column of the clarifier and then upwardly and radially out from the clarifier without underground pipes, including retrofitting existing floor-effluent clarifiers to eject the settled sludge upwardly and outwardly. These and other objects, advantages and features of the invention will be apparent from the following description of a preferred embodiment, considered along with the accompanying drawings.
SUMMARY OF THE INVENTION
In the clarifier system of the invention, a clarifier tank is built with or retrofitted with piping and a pump to withdraw settled sludge from the bottom of the tank upwardly through the tank's center column and radially out from that column via an exit pipe which can be secured to a fixed walkway, or other means.
At the bottom end of the central tower, and preferably supporting the central tower, is a special manifold device similar to what is shown in U.S. Pat. No. 5,340,485, but installed in a different way and for a different purpose. In the invention the special manifold device, with one or more side branch pipes extending from a central hub outwardly to and through a peripheral wall, is positioned upside down relative to the '485 patent, with an effluent end of the hub oriented upwardly. Three branch pipes, of relatively large diameter and preferably at equal angular intervals, may be provided. The special manifold device, which has sometimes been known as a CMD in its previous uses, can be installed directly down against a foundation or pedestal at the tank bottom, such pedestal being sufficient to support the central column of the clarifier. The special manifold device or CMD preferably is substantially open from top to bottom, within the space defined by the peripheral wall (which typically is cylindrical but could be a polygonal shape if desired), interrupted only by the central hub and pipe branches extending radially through that space. The open upper end of the hub receives settled sludge that has been collected through the pipe branches, and the sludge is drawn upwardly through a vertical RSS (return settled sludge) pipe connected in sealed relationship with (or integral with) the central hub.
At the top of the central column the RSS pipe turns outwardly, i.e. is connected to an essentially horizontal exit pipe to carry the RSS outwardly away from the tank. A sludge withdrawal pump preferably is located on the exit pipe outside the tank, although it could be other locations along that pipe.
If needed the hub and the connected vertical RSS pipe can be off-center in the special manifold device, in order to properly pass through the drive assembly up near the top of the column. The location of the RSS pipe within the column will depend on size of the RSS pipe and the configuration of the drive assembly through which it must pass.
At the bottom of the tank the special manifold device or CMD has its radial openings in communication with the wastewater in the tank, and particularly with the settled sludge at the bottom of the tank. A larger-diameter, conventionally used sludge shield often is included in the tank, this large manifold simply being a large cylinder closed at its top and with side openings, to assure that sludge is collected from locations spaced outwardly from the center column. This is to assure that clarified water, typically present immediately around the center column above the bottom, will not be drawn out along with sludge.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top plan view, with portions broken away, showing a clarifier which includes the system of the invention.
FIG. 2 is a side elevation view showing the clarifier tank and system.
FIG. 3 is a more detailed elevation view showing a portion of the clarifier and illustrating the system of the invention.
FIG. 4 is a detailed elevation view showing, partially in cross section, the bottom center portion of the clarifier tank with equipment according to the invention.
FIG. 4A is a detail view in perspective showing a special manifold device of the invention, known as an RMD (reverse manifold device).
FIG. 5 is another detail view at the bottom center of the tank, showing the bottom of the center column and the important components of the invention.
FIG. 6 is a detail section elevation view showing a fixed walkway of the clarifier tank system.
DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 shows, in a fragmentary top plan view, a clarifier 10 that includes a tank 12 , a center column 14 , a fixed platform 16 , a fixed walkway 18 for service access to equipment via the platform 16 , and rotational apparatus including rake arms 20 and 22 and a feedwell 24 which extends down approximately from the liquid level in the tank about four to six feet, sometimes more. The tank apparatus includes a drive unit for rotating the rotatable components, the drive unit not being clearly seen in the drawing, but typically located at the top of the center column 14 and connected to a driving cage that extends down to the rake arms. Above the rake arms are skimmer blades, not clearly seen in FIG. 1 . Feedwell supports are shown at 26 , supporting the feedwell from the rake arms 20 , 22 below and from stub arms 28 below.
FIG. 1 also shows an RSS exit pipe 30 which is included in the clarifier system according to the invention. The RSS exit pipe 30 is supported, preferably suspended from, the walkway 18 , and comes out of the center column 14 as indicated.
FIG. 2 shows the system in side elevation view, better illustrating the RSS exit pipe 30 and its relationship to the walkway 18 and the center column 14 from which it emerges. The pipe 30 extends up from the interior of the center column and, in this embodiment, bends out and down to the straight section shown leading generally radially out from the clarifier. A pump is indicated at 32 , just outside the clarifier. This pump, which draws sludge up from the bottom of the clarifier, could be at other locations along the RSS pipe 30 .
FIG. 2 also shows a wastewater influent pipe at 34 , shown partially behind the RSS exit pipe 30 . As indicated by a direction arrow, the influent pipe 34 directs wastewater into a cordoned space near the surface, defined by the feedwell 24 . An energy dissipating inland (EDI) can be included at the outlet of the influent pipe 34 .
FIG. 2 also shows spiral wiper blades 36 extending to the tank floor from the rake arms. Skimmer blades 38 are shown at the top of the rotating apparatus, rotatable with the rake arms 20 , 22 and the feedwell 24 .
FIG. 3 shows the clarifier system in greater detail, but with a portion of the left side not shown. In FIGS. 3 and 4 a wastewater influent pipe 40 is shown entering the center column or influent column 14 from beneath, for a system wherein this influent pipe is embedded in the concrete bottom of the tank. In this case the center column or influent column carries the influent up to the feedwell 24 , the influent exiting the influent column through exit ports 42 , preferably into an energy dissipating inlet (EDI) 44 . This influent equipment is conventional, the embedded pipe 40 being an alternative to the above-liquid influent pipe 34 shown in FIG. 2 .
FIG. 3 shows the sludge exit pipe 30 at a different location on the walkway than FIGS. 1 and 2 .
With the invention, sludge accumulated at the bottom of the tank 12 and gathered toward the center along the sloping bottom by the rakes is fed up through a vertical RSS pipe 50 which is indicated as being within the center column or influent column 14 . This can be, for example, a 24 inch pipe contained within a much larger center column which might be 48 inches outside diameter. The withdrawn RSS enters a special manifold device indicated at 52 in FIG. 3 , the sludge entering essentially radially inwardly through openings in the periphery of the manifold device 52 and then up through the vertical RSS pipe 50 . In another use such a manifold device has been called a CMD or collection manifold device. Here it can be called an RMD or reverse manifold device. The manifold device 52 , as further described below, does not block flow of influent wastewater if the wastewater is delivered through a subterranean influent pipe such as shown at 40 . The inflowing wastewater can flow through the manifold device 52 , isolated from the exiting RSS, and up through the influent column 50 .
In FIG. 4 the CMD or RMD or manifold device 52 is shown connected at the bottom of the center column 14 . FIG. 4A schematically shows the special manifold device 52 in one preferred form prior to incorporation into the system of the invention. The manifold device 52 or CMD has an annular vertical wall 54 , preferably cylindrical but which could also be another shape, such as polygonal, and a center hub 56 with a solid bottom as seen in this schematic view. The center hub 56 may not be at center, but can be off-center within the outer ring or wall 54 so as to allow the outflow RSS pipe 50 ( FIGS. 3 and 4 ) to be off-center when needed so as to pass through the drive unit with adequate clearance. As FIG. 4A shows, the hub 56 is connected by at least one, and preferably two or three, pipe branches 58 that are open to the interior of the center hub and connect to holes 60 in the outer ring or peripheral wall 54 . These pipe branches 58 provide conduits for inflow of settled sludge, inwardly toward the interior of the central hub 56 and then upwardly into the vertical RSS pipe 50 indicated in FIGS. 3 and 4 . In FIG. 4 one of the branch pipe holes 60 is seen, and the central hub 56 is indicated in dashed lines, off-center in this particular implementation.
The CMD or manifold device 52 allows flow of wastewater up through the device, isolated from RSS being removed, as indicated by the arrow in FIG. 4A . FIG. 4A shows that the center hub 56 is closed at its bottom end 62 . The upper end of the manifold device 52 is secured to the bottom end of the center column 14 , which can be by a lip or flange 64 on the manifold device that can be coupled by bolts or welding to a similar flange secured to the bottom end of the center column 14 . Another mounting flange 66 at the bottom side of the CMD or manifold device 52 can be used to secure the CMD down to the tank floor or to a pedestal 68 which would normally receive the bottom end of the center column.
The upper end of the hub 56 is secured to the vertical RSS pipe 50 as shown in FIG. 4 . This can be by welding, securement using a sealing sleeve, or other means. The center hub could be a longer section of pipe if desired, with a coupling, such as a threaded sleeve, to connect it to the bottom of the RSS pipe 50 .
In some implementations the manifold device 52 is formed integrally at the bottom end of the center column or influent column 14 ( FIG. 5 can be considered an example of this). The center column is simply of the proper length to bear against the pedestal 68 , and pipe branches 58 are welded to the interior of the center column at holes such as shown at 60 , and to a center hub connectable to a vertical RSS pipe. This can conveniently be done in a new installation, as opposed to a retrofit where the existing center column is saved, although it can be done in either case. The lower end part of the column in this integral installation is considered to have the RMD or reverse manifold device 52 .
FIG. 4 also shows an outer manifold or sludge shield 70 as discussed above. The sludge shield 70 is designed to cause settling sludge to accumulate somewhat outwardly from the center of the tank, spaced away from the inlet holes 60 of the CMD or special manifold device 52 . Such sludge shields have been used previously for conventional systems wherein accumulated sludge is directed downwardly through a floor pipe and removed from beneath the floor. This generally keeps clarified water from being discharged with sludge. The shield 70 has a closed top and can be a large-diameter simple cylinder, with large exterior holes as indicated at 72 in FIG. 4 . As shown in the detailed view of FIG. 5 , the sludge shield 70 , which may have diameter of seven feet or more in a large clarifier wherein the manifold device 52 is about four or five feet in diameter, is positioned against the tank floor 74 and can have rectangular inlet openings 76 . FIG. 5 shows a center column 14 with the CMD/RMD or manifold device 52 at its bottom end, and this could be an integral installation such as described above. One of the manifold device intake holes 60 is seen in FIG. 5 . The manifold device, or the base of the center column 14 in the case of a integral installation, is shown secured down into the concrete pedestal 68 by anchor bolts 78 .
FIG. 6 shows a preferred construction for support of influent wastewater and effluent sludge (RSS) pipes which are also seen in FIGS. 1, 2 and 3 . The walkway 18 has a walkway base structure 80 to which are connected pipe hangers 82 and 84 . The wastewater influent pipe 34 , larger in diameter than the RSS exit pipe 30 , is shown suspended generally centrally from the walkway structure, while the RSS exit pipe 30 is shown suspended from a position to the side of the other pipe, which is also seen in FIGS. 1 and 2 . The top edge of the tank wall is illustrated in relation to these pipes, at 86 .
For installation of the invention in an existing clarifier apparatus, where the center column is to be retained, the base of the center column is disconnected from the floor or pedestal, then raised up and cut to a shorter length as needed to accommodate the RMD to be installed. The RMD is designed and configured to fit the diameter of the center column and with a hub positioned in a proper location for the desired location of the vertical RSS pipe, which has been determined based on a proper location for the RSS pipe to pass through the drive unit above, with adequate clearance. The RSS pipe is lowered into the column from the top and secured at its bottom end to the hub of the RMD. A new attachment flange is welded to the cut column end, and the RMD is secured to the bottom of the column in a sealed connection. Then the RMD is secured down to the floor or pedestal. This could be using the same array of bolts that secured the column, if they are in good condition.
For a new clarifier system, or in a situation where an existing center column is to be replaced, the RMD can be built into the bottom of a new center column, as described above with reference to FIGS. 4 and 5 . Again, the center hub of the RMD is located as needed so that the attached RSS pipe can pass properly through a drive unit above. The column is bolted down to the floor or pedestal in the usual way. Note that a separately-formed RMD could be secured to the bottom of a new center column if desired, but in the case of a new column it is usually preferred to form the RMD as an integral part of the column. Further, it is also possible to form an integral RMD in an existing, reused center column, but this would generally not be preferred because of the more difficult conditions for cutting holes in the column and welding the branch pipes in place.
The above described preferred embodiments are intended to illustrate the principles of the invention, but not to limit its scope. Other embodiments and variations to these preferred embodiments will be apparent to those skilled in the art and may be made without departing from the spirit and scope of the invention as defined in the following claims. | In a wastewater treatment plant a clarifier is fitted with piping and a pump to withdraw settled sludge from the bottom of the tank upwardly through the tank's center column and radially out from the clarifier via an exit pipe above the liquid level. The exit pipe can be supported on a fixed walkway. At the bottom end of the central tower is a manifold device for collecting settled sludge, including an annular preferably cylindrical wall, a central pipe hub and at least one pipe branch extending from an opening in the cylindrical wall radially inwardly to the central hub. Sludge is drawn up through a vertical sludge return pipe by a pump located preferably above the tank's liquid level, drawing sludge into pipe branches of the manifold device and through the hub to the sludge return pipe, then out through the exit pipe. | 1 |
RELATED APPLICATION INFORMATION
[0001] The present application claims priority to and the benefit of German patent application no. 10 2012 219 769.9, which was filed in Germany on Oct. 29, 2012, the disclosure of which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a method for producing an electrical feedthrough in a substrate, and to a substrate having an electrical feedthrough.
BACKGROUND INFORMATION
[0003] Electrical feedthroughs in a substrate or in a subarea of a substrate, such as a wafer, for example, exist in a wide variety of embodiments. The aim is always to achieve as small as possible a feedthrough at a low electrical volume resistance. To achieve that, frequently a narrow through-hole with almost vertical walls is produced in the substrate concerned, the wall is electrically insulated, and then the through-hole is completely or partially filled with a metal or a metal alloy in order to obtain the desired low volume resistance.
[0004] Depending on the application, that known approach is subject to limitations. On the one hand, there are applications in which the presence of metal produces interference. As an example of numerous MEMS applications, the micromechanical pressure sensor may be mentioned here.
[0005] FIG. 3 shows a schematic cross-sectional illustration to explain the set of problems underlying the present invention, with reference to an example of a substrate having an electrical feedthrough and a pressure sensor.
[0006] In FIG. 3 , reference numeral 2 denotes a silicon semiconductor substrate. A first region 1 having an electrical feedthrough 6 a and a second region 11 having a micromechanical component in the form of a pressure sensor are provided in silicon semiconductor substrate 2 . Feedthrough 6 a is connected to a first electrical contact terminal DK 1 of pressure sensor 11 a via a strip conductor 15 a on front side V of substrate 2 . Pressure sensor 11 has a diaphragm 3 which is provided over a cavity 3 a. A piezoresistive resistor 4 and an isolation well 4 a situated therebeneath are diffused into diaphragm 3 . First electrical contact terminal DK 1 and, in addition, a second electrical contact terminal DK 2 contact piezoresistive resistor 4 in such a way that the piezoelectric resistance is detectable between them.
[0007] A first insulating layer I 1 is provided between electrical metal strip conductor 15 a and front side V of substrate 2 . A second insulating layer I 2 is provided between a back-side electrical metal strip conductor 15 b and back side R of substrate 2 . Insulating layers I 1 and I 2 may, for example, be oxide layers. Feedthrough 6 a connects front-side strip conductor 15 a to back-side strip conductor 15 b. A wall insulating layer 7 a, which is likewise made of oxide, for example, isolates feedthrough 6 a from surrounding substrate 2 . Lastly, reference numeral 9 denotes what is referred to as a seed layer for applying the metal of feedthrough 6 a, which at the same time may be used as a diffusion barrier.
[0008] In such classical micromechanical pressure sensors 11 , deformation of silicon diaphragm 3 , which is disposed on silicon substrate 2 , is measured by way of the piezoresistive resistance. When the pressure changes, the deformation of diaphragm 3 , and hence the resistance signal of piezoresistive resistor 4 , changes. Owing to the differing material parameters of silicon and metal, even the narrow metal strip conductors 15 a situated on the surface and in the vicinity of diaphragm 3 cause voltages which are transmitted via substrate 2 to diaphragm 3 . It is possible with some effort to compensate for the temperature-dependent component of the voltages. However, the inelastic properties of many metals also cause hysteresis in the characteristic curve of the pressure sensor. It is not possible to compensate for that effect. When metallic regions are provided not only at the surface but also at a depth within substrate 2 , distinctly greater adverse effects on voltage-sensitive components, such as pressure sensors, for example, are also expected.
[0009] On the other hand, there are a number of applications in which primarily also high voltages or also only high voltage peaks (ESD, for example) are to be conducted through a substrate or a subarea of the substrate via an electrical feedthrough. This proves to be difficult with the approach described above. Isolation of the etched through-holes is usually achieved by oxide deposition. The achievable oxide thicknesses are greatly limited by the process control and the specific geometry. Accordingly, the maximum dielectric strength is also greatly limited. In addition, the surface of the through-holes, which is formed using a trench etching process or a laser process, is rather rough. That roughness causes electric field peaks which likewise reduce the dielectric strength.
[0010] Alternative approaches that manage without metals are not usable in many applications, since only with metals is it possible to achieve the extremely low volume resistances that are often necessary.
[0011] FIG. 4 shows a schematic cross-sectional illustration to explain the set of problems underlying the present invention, with reference to a substrate having an electrical feedthrough and a pressure sensor as known from German patent document DE 10 2010 039 330 A1.
[0012] Substrate 2 shown in FIG. 4 has an electrical feedthrough 6 running through substrate 2 from its front side V to its back side R. An annular isolation trench IG in substrate 2 surrounds electrical feedthrough 6 and is closed off by first insulating layer I 1 on front side (V) and by second insulating layer I 2 and a closing layer 18 on back side R of substrate 2 . A thin liner-shaped insulating layer 18 ′ is formed on the walls of annular isolation trench IG. Annular isolation trench IG may be filled or unfilled (as illustrated). An annular substrate region 2 a surrounds electrical feedthrough 6 . An electrical contact terminal DK 3 to electrical feedthrough 6 is formed on back side R of substrate 2 . An electrical strip conductor 5 is formed on front side V of substrate 2 between a contact ring 5 a, situated on electrical feedthrough 6 , and pressure sensor 11 a. Thereover, a dielectric protection layer 16 , for example made of nitride, is formed.
[0013] The subject matter of German Patent document DE 10 2010 039 330 permits the production of metallic feedthroughs through a substrate, with a high dielectric strength and voltage decoupling between the metalized region and the substrate being possible.
[0014] The method from German patent document DE 10 2010 039 330 is, however, relatively laborious and expensive. In addition, the combination disclosed therein of metallic punch and separate isolation ring permits only relatively large feedthroughs to be produced.
SUMMARY OF THE INVENTION
[0015] The present invention provides a method for producing an electrical feedthrough in a substrate, having the features described herein, and a substrate with an electrical feedthrough, having the features described herein.
[0016] By virtue of the present invention, a feedthrough and a corresponding production method are made available which make it possible to form, instead of a metallic feedthrough, a feedthrough that makes use of a low-resistance metal silicide layer which may be produced in a simple manner on a trenched substrate punch. The feedthrough according to the invention saves on space and at the same time has a low resistance, a high dielectric strength and also low parasitic capacitances.
[0017] An aspect of the present invention resides in the formation of a substrate punch in the substrate, which substrate punch is isolated by an annular trench and onto which a metal layer is conformally deposited. At the interface between metal layer and silicon of the silicon semiconductor substrate, a metal silicide layer is formed by a temperature step or another type of activation. Thereafter, the excess metal is selectively removed to the silicide layer. The resulting silicon punch with the surface metal silicide layer serves as a low-resistance feedthrough. The annular region which is trenched to form the punch serves as insulation since, at the base of the annulus and at the upper side of the annulus, the pre-product (metal layer) of the silicide layer may be removed relative to the silicide layer and nor is any silicide able to form in that region.
[0018] The resulting substrate punch coated with the metal silicide layer may be connected to one or more components at the front side and at the back side in a simple manner via electrical strip conductors.
[0019] The main advantages of that type of feedthrough reside in high dielectric strength, low leakage currents, low parasitic capacitances, low electrical resistance, and in the independence of the resistance of the feedthrough and the substrate doping. In particular, very small feedthroughs having high aspect ratios may be obtained, it also being possible to obtain the feedthroughs in very thick substrates and especially to form feedthroughs having a planar surface.
[0020] Further developments form the subject matter of the respective further embodiments described herein.
[0021] Further features and advantages of the present invention are described below with the aid of embodiments and with reference to the Figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIGS. 1 a to 1 l show schematic cross-sectional illustrations to explain various process stages of a method for producing an electrical feedthrough in a substrate according to a first embodiment of the present invention.
[0023] FIG. 2 shows a schematic cross-sectional illustration of a substrate with an electrical feedthrough in use for encapsulation of a MEMS wafer according to a second embodiment of the present invention.
[0024] FIG. 3 shows a schematic cross-sectional illustration to explain the set of problems underlying the present invention, with reference to an example of a substrate having an electrical feedthrough and a pressure sensor.
[0025] FIG. 4 shows a schematic cross-sectional illustration to explain the set of problems underlying the present invention, with reference to a substrate having an electrical feedthrough and a pressure sensor as in German patent document DE 10 2010 039 330 A1.
DETAILED DESCRIPTION
[0026] In the Figures, identical or functionally identical components are denoted by the same reference symbols.
[0027] FIGS. 1 a to 1 l show schematic cross-sectional illustrations to explain various process stages of a method for producing an electrical feedthrough in a substrate according to a first embodiment of the present invention.
[0028] As shown in FIG. 1 a , a micromechanical component 11 a in the form of a pressure sensor, which has already been explained in detail with reference to FIG. 3 , is provided in a silicon semiconductor substrate 2 .
[0029] Reference symbol IU denotes a lower insulating layer, for example made of oxide or nitride, on front side V of silicon semiconductor substrate 2 , on which insulating layer a strip conductor 15 ′ is formed which electrically contacts silicon semiconductor substrate 2 in a step-shaped manner in a contact region KB. In addition, electrical strip conductor 15 ′ is connected to electrical contact terminal DK 1 of pressure sensor 11 a.
[0030] Above lower insulating layer IU and electrical strip conductor 15 ′ there is an upper insulating layer IO, for example likewise made of oxide or nitride, which constitutes a front-side passivation.
[0031] To form electrical strip conductor 15 ′, one or more metal layer(s) may be deposited with or without diffusion barriers or adhesive layers. A W or Cu or Al metal layer with a Ti/TiN or TaN/Ta barrier may be used. After the deposition, appropriate patterning is carried out in a photolithographic process.
[0032] Further, with reference to FIG. 1 b , silicon semiconductor substrate 2 may be ground on back side R to reduce the thickness of silicon semiconductor substrate 2 by a differential thickness d which is based, for example, on the height of the feedthrough that is to be formed. Back side R may in that case be conditioned using a back-etch process in a plasma process or in a liquid etching medium or in a CMP process.
[0033] As shown in FIG. 1 c , a back-side insulating layer IR is then applied to back side R, for example an oxide layer.
[0034] In a process step that then follows, which is illustrated in FIG. 1 d , a fine grid G is then patterned into back-side insulating layer IR in a grid region GB, grid region GB lying opposite contact region KB on front side V. Grid region GB therefore lies in the region in which a trench for the feedthrough is subsequently to be created. In grid region GB, back side R of silicon semiconductor substrate 2 is laid bare.
[0035] At the center of grid G opposite contact region KB, grid G is then closed off in a closing region VB, an annular open region OB surrounding closing region VB. An appropriate plug of a closing layer VS may be formed, for example, from photoresist which may later be selectively removed. This is illustrated in FIG. 1 e.
[0036] Further, with reference to FIG. 1 f , silicon semiconductor substrate 2 is trenched higher from back side R in order to form an annular trench 20 in silicon semiconductor substrate 2 , which trench 20 extends from back side R to front side V. The process parameters are chosen here in such a way that the silicon of silicon semiconductor substrate 2 is completely removed under open region OB of grid region GB, where applicable with additional lateral under-etching. The etching process stops at lower insulating layer IU on front side V of the substrate and in a specific variant, as shown, also partly at electrical strip conductor 15 ′. In that manner, a low resistance of the feedthrough may be achieved in the further course of the process, since electrical strip conductor 15 ′ may be connected directly to the metal silicide layer that is to be formed in the subsequent course of the process.
[0037] As shown in FIG. 1 g , the plug made of resist of closing layer VS, which plug forms closing region VB, is subsequently selectively removed to back-side insulating layer IR over silicon substrate punch 2 a situated at the center of annular trench 20 .
[0038] Then, as shown in FIG. 1 h , a metal layer 40 is deposited over back side R in a conformal deposition process, metal layer 40 being deposited also in annular trench 20 on the surface of silicon semiconductor substrate 2 and on lower insulating layer IU and strip conductor 15 ′ on front side V. Grid region
[0039] GB may also be closed again in the process. A grid region GB that is still open is equally possible.
[0040] Suitable metals are, for example, Ti, Ni, Co, Pt or W, which are able to form low-resistance silicide phases with silicon with low activation energy. The deposition may be carried out in a simple sputtering process. In the case of high aspect ratios, which may be conformal depositions, such as, for example, an MOCVD deposition (metallo-organic chemical vacuum deposition) or an ALD deposition (atomic layer deposition), are used.
[0041] As shown in FIG. 1 i , in the process of deposition of metal layer 40 or subsequently by a separate process step (for example oven, RTP, laser anneal), a thermal silicide reaction is activated between metal layer 40 and the regions covered by metal layer 40 in annular trench 20 of silicon semiconductor substrate 2 , which leads to the formation of a metal silicide layer 41 on the walls of annular trench 20 and on the underside of substrate punch 2 a. In particular, metal silicide layer 41 is also in electrical contact with front-side strip conductor 15 ′.
[0042] Then, as illustrated in FIG. 1 j , the excess metal of metal layer 40 and the metal of metal layer 40 that has not been deposited on back-side insulating layer IR of silicon semiconductor substrate 2 is selectively removed to metal silicide layer 41 .
[0043] A wet-chemical process using H 2 SO 4 may be used for that purpose. Particularly on lower insulating layer IU and front-side electrical strip conductor 15 ′, the excess metal of metal layer 40 is completely removed again in that operation, so that isolation from the surrounding substrate 2 is ensured.
[0044] Substrate punch 2 a, coated with metal silicide layer 41 , of silicon semiconductor substrate 2 is therefore linked on front side V of silicon semiconductor substrate 2 via electrical strip conductor 15 ′ to micromechanical component 11 a in the form of the pressure sensor. It will be appreciated that linking to further components also may be carried out by providing further electrical strip conductors (not shown). An electrical feedthrough WDK is thus created.
[0045] As illustrated in FIG. 1 k , grid G is then closed off by a back-side closing layer VR, for example an oxide layer or a nitride layer.
[0046] In one process step (not shown), annular region 20 may be completely or partially filled with a further insulating layer beforehand to offer even better isolation.
[0047] Lastly, with reference to FIG. 11 , a back-side contact region KB′ is formed opposite front-side contact region KB, and a back-side contacting of punch 2 a coated with metal silicide layer 41 is created by way of a back-side electrical strip conductor 15 ″. The advantage with that arrangement is that, by way of the lower region of metal silicide layer 41 , it is possible to create a direct electrical contact to the region of metal silicide layer 41 surrounding substrate punch 2 a.
[0048] On closing layer VR it is possible to form, by suitable metal deposition and patterning, any desired redistribution layer, for example with connections to further back-side components, FIG. 11 showing, for reasons of simplicity, only back-side electrical strip conductor 15 ″.
[0049] Thereafter, it is then possible, for example by applying balls of solder to back-side strip conductor 15 ″, to mount silicon semiconductor substrate 2 with feedthrough WDK on a circuit board or on some other housing using the flip-chip method.
[0050] Optionally, still further components or other structures may also be formed on back side R of silicon semiconductor substrate 2 and be connected to feedthrough WDK beforehand.
[0051] FIG. 2 shows a schematic cross-sectional illustration of a substrate with an electrical feedthrough in use for encapsulating a MEMS wafer according to a second embodiment of the present invention.
[0052] In the case of the embodiment shown in FIG. 2 , instead of the single silicon semiconductor substrate 2 , a stack of substrates is provided, reference symbol W 1 denoting a first substrate with a base wafer S 1 and, situated thereon, a micromechanical function layer MF on which a second substrate WK having a feedthrough WDK according to the embodiment is disposed, a small ball of solder LK being provided on a strip conductor 15 ″ on the top side of substrate WK having feedthrough WDK for the purpose of flip-chip bonding. Second substrate WK is bonded onto first substrate W 1 as an encapsulation.
[0053] Although the present invention has been described with reference to several exemplary embodiments which may be combined with one another as desired, the present invention is not limited thereto but may be further modified in various ways.
[0054] In particular, the materials mentioned above are merely examples and are not to be construed as being limiting. In addition, the micromechanical components such as the pressure sensor, the strip conductors, and further electrical components, for example, may be produced in or on the substrate either before or after production of the feedthroughs.
[0055] It will be appreciated that any desired additional protective, insulating, passivation and diffusion barrier layers may be deposited to further increase the reliability.
[0056] Although substrate punch 2 a or feedthrough WDK is shown as being cylindrical in the embodiment illustrated in FIGS. 1 a through 1 , it is possible to depart from cylindrical punch shapes and use rectangular or square punch shapes if especially space-saving yet low-resistance feedthroughs are required. It is also possible to use, for example, star-shaped punch shapes, that is to say, punch shapes that have a large surface in comparison with their volume. Furthermore, it is also possible to adjust any desired resistances even within a chip by way of the shape of the stacks for the feedthroughs.
[0057] In many other feedthrough concepts, the resistance may be obtained only through parallel connection of a plurality of feedthroughs not scalable at chip level. | A method for producing an electrical feedthrough in a substrate having an electrical feedthrough, including: forming an etch stop layer on the front side of the substrate; forming a mask on the back side of the substrate; forming an annular trench in the substrate, which trench extends from the back to the front side, by an etching process that stops at the etch stop layer, using the mask, the trench surrounding a substrate punch; depositing a metal layer over the back side of the substrate using the mask, the metal layer penetrating into the annular trench and being deposited on the substrate punch; forming a metal silicide layer on the substrate punch by at least partially converting the metal layer into the metal silicide layer on the substrate punch; selectively removing a remainder of the metal layer; and closing off the annular trench at the back side of the substrate. | 7 |
This application is a continuation of U.S. application Ser. No. 09/436,186, filed Nov. 8, 1999, now U.S. Pat. No. 6,406,604.
FIELD OF THE INVENTION
The present invention relates generally to the analysis of chemical and biological materials and, more particularly, to an improved electrophoresis apparatus which simultaneously performs multiple analyses on a plurality of analytes.
BACKGROUND OF THE INVENTION
Electrophoresis is a known technique for separating and characterizing constituent chemical and/or biological molecules, or analytes, present in simple and complex matrices undergoing analysis. Candidate sample compounds include drugs, proteins, nucleic acids, peptides, metabolites, biopolymers and other substances which exist in simple and complex forms.
Conventional systems are based on interchangeable cartridges which house a thin capillary tube equipped with an optical viewing window that cooperates with a detector. Sample solutions and other necessary fluids are placed in vials (cups) positioned beneath inlet and outlet ends of the capillary tube by means of a rotatable table.
When high voltage is applied to a capillary filled with an appropriate solution and/or matrix, molecular components migrate through the tube at different rates and physically separate. The direction of migration is biased toward an electrode with a charge opposite to that of the molecules under investigation. As the molecules pass the viewing window, they are monitored by a UV or other detector which transmits an absorbance or appropriate signal to a recorder. The absorbance or appropriate values are plotted as peaks which supply analytical information in the form of electropherograms.
Electrophoresis separation relies on the different migration of charged particles in an electric field. Migration speed is primarily influenced by the charge on a particle which, in turn, is determined by the pH of the buffer medium. Electric field strength and molecular size and shape of the analyte also influence migration behavior.
Electrophoresis is a family of related techniques that perform high efficiency separations of large and small molecules. As one embodiment of this science, capillary electrophoresis is effective for obtaining rapid and high separations in excess of one-hundred-thousand plates/meter. Because it is a non-destructive technique, capillary electrophoresis preserves scarce physical samples and reduces consumption of reagents. A fused silica (quartz) capillary, with an inner bore diameter ranging from about 5 microns to about 200 microns and a length ranging from about 10 centimeters to about 100 centimeters, is filled with an electrically conductive fluid, or background electrolyte, which is most often a buffer. Since the column volume is only about 0.5 to about 30 microliters, the sample introduction volume is usually measured in nanoliters, picoliters and femtoliters (ideally 2% of the total volume of the column). As a consequence, the mass sensitivity of the technique is quite high.
Improved instrumentation and buffer-specific chemistries now yield accurate peak migrations and precise area counts for separated analytes. But, capillary electrophoresis is still limited by concentration sensitivity.
To overcome this deficiency, a series of solid-phase micro-extraction devices have been developed for selective and non-selective molecular consolidation. These devices, which are used on-line with a capillary tube, are commonly known as analyte concentrators containing affinity probes to bind target compounds. Typical embodiments are described in U.S. Pat. No. 5,202,010 which is incorporated by reference in this disclosure. Other relevant teachings are provided by U.S. Pat. No. 5,741,639 which discloses the use of molecular recognition elements; and U.S. Pat. No. 5,800,692 which discloses the use of a pre-separation membrane for concentrating a sample.
Even with the advent of analyte concentrators, there is still a need to improve the sensitivity levels for samples that exist in sub-nanomolar quantities. This deficit is particularly acute in the clinical environment where early detection of a single molecule may be essential for the identification of a life-threatening disease.
Known capillary electrophoresis instruments are also limited by low-throughput, i.e., the number of samples that can be analyzed in a specified period of time. U.S. Pat. No. 5,045,172, which is incorporated by reference, describes an automated, capillary-based system with increased analytical speed. The '172 patent represents a significant improvement over the prior art. But, throughput is still relatively low because the instrument uses only one capillary which performs single sample analyses in approximately 30 minutes.
U.S. Pat. No. 5,413,686 recognizes the need for a multi-functional analyzer using an array of capillary tubes. Like other disclosures of similar import, the '686 patent focuses on samples having relatively high concentrations. There is no appreciation of the loadability and sensitivity necessary for analyzing diluted samples, or samples present at low concentrations in a variety of liquids or fluids.
Based on these deficiencies, there exists an art-recognized need for an electrophoresis instrument having higher loadability, better detectability of constituent analytes, faster throughput and multi-functional capability for analyzing a plurality of components in a single sample and/or a plurality of samples with high and low concentrations using a variety of chromophores, detectors and/or pre-concentration devices.
OBJECTS OF THE INVENTION
Accordingly, it is a general object of the present invention to provide an improved electrophoresis apparatus having at least one transport capillary, at least one separation capillary and an analyte concentrator positioned therebetween;
It is another object of the present invention to provide an electrophoresis apparatus having greater operating efficiency, detectability and throughput.
An additional object of the present invention is to provide a user-friendly, sample preparation step which is designed to eliminate unwanted analytes that occupy binding sites and contaminate the inner walls of capillaries or channels.
A further object of the present invention is to provide an electrophoresis apparatus that can analyze multiple samples having a single constituent, or multiple constituents of a single sample.
It is a further object of the present invention to provide an electrophoresis apparatus which uses more than one analyte concentrator to sequentially bind more than one analyte in a single complex matrix, or in multiple matrices of simple or complex configuration.
It is yet another object of the present invention to provide an electrophoresis apparatus having enhanced loadability and sensitivity which is capable of analyzing samples present in a wide range of concentrations, including those found at low concentrations in diluted liquids or fluids with simple or complex matrices.
It is a further object of the present invention to provide an electrophoresis apparatus that delivers high-throughput for screening and analyzing a wide variety of samples in multiple application areas, utilizing a single or multiple dimension separation principle or mode.
Another object of the present invention is to provide an electrophoresis apparatus which uses more than one separation method to sequentially permit binding to, and elution from, an analyte concentrator to effect the separation of one or more analytes.
It is another object of the present invention to provide an automated, miniaturized desk-top electrophoresis apparatus for bioanalysis and other applications.
Additional objects of the present invention will be apparent to those skilled in the relevant art.
SUMMARY OF THE INVENTION
In one aspect of the invention, a sample including a number of analytes of interest is passed through a relatively large-bore transport capillary orthogonal to a plurality of smaller-bore separation capillaries. An analyte concentrator is positioned at each intersection of the transport capillary and separation capillaries.
After the sample has been passed through each of the analyte concentrators, and after the analytes of importance are captured by each concentrator matrix, a selected buffer is applied to each analyte concentrator to free the system of salts and other non-relevant components. For example, a typical buffered solution is sodium tetraborate having a pH in the range of 7.0 to 9.0. The bound analytes are then eluted from each concentrator matrix in a sequentially time-controlled fashion using an aliquot or plug of an optimal eluting solution. The process continues until each of the analytes has been removed from the concentrator matrices and passed through the detector by high resolution electrophoresis migration. To increase the sensitivity of the analytes, an additional analyte concentrator containing a chromophoric reagent may be placed in one or more of the separation capillaries to react with the analyte present in that capillary. Alternatively, the eluting solution may contain a chromophoric reagent allowing decoupling and derivatization to occur simultaneously. The derivatized analytes can then be isolated in the separation capillary.
To separate and analyze multiple samples with the electrophoresis apparatus of the invention, individual separation capillaries are provided, each of which contains an analyte concentrator that enriches the analytes present in diluted solutions of low concentration. Multiple elutions are carried out in a manner similar to that performed when analyzing a single sample. Effective results can also be achieved using solutions that contain an appropriate eluting chemical and a chromophoric reagent to simultaneously elute the targeted analyte and enhance sensitivity. As with a single-sample analyzer, an extra analyte concentrator may be placed in one or more of the separation capillaries to allow on-line derivatization of analytes to achieve even further enhancement of concentration sensitivity. In addition, an extra analyte concentrator may be placed in one or more of the separation capillaries to permit biochemical reactions, such as the on-line cleavage of proteins to generate peptides.
An analyte concentrator may also be used to quantify enzymatic products generated by the action of one or more pharmacological agents during a specific enzyme reaction. Furthermore, the use of an analyte concentrator coupled to a different mode of electrophoresis can be used to differentiate structurally related substances present in biological fluids or tissue specimens. For example, the identification and characterization of natural proteins from artificially-made proteins or other chemicals in serum.
All reactions described above can be performed in an apparatus containing a format that includes either capillaries or channels. In addition, the migration of analytes can be accomplished by an electrical or mechanical pump.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the electrophoresis apparatus of the present invention;
FIG. 2 is an enlarged, elevated view of a plurality of analyte concentrators stationed at the respective intersections of a large bore transport capillary and an equal plurality of small bore separation capillaries;
FIG. 3 is an elevated view of a second embodiment of the present invention, showing a plurality of analyte concentrators stationed at the respective intersections of an alternative transport channel and an equal plurality of separation channels;
FIG. 3A is an enlarged view of the described intersection containing the analyte concentrator microstructure;
FIG. 4 is an enlarged, elevated view of an analyte concentrator stationed at the intersection of a transport capillary and a separation capillary;
FIG. 5 is an elevated view of an analyte concentrator in the form of a cross-shaped capillary;
FIG. 6 is an elevated view of the electrophoresis apparatus of the present invention, showing an analyte concentrator disposed along the length of a separation capillary;
FIG. 7 is a perspective view of a third embodiment of the present invention, showing a plurality of separation capillaries connected to a single outlet capillary for sequential detection; and
FIG. 8 is a perspective view of a fourth embodiment of the present invention, showing a plurality of separation capillaries adapted to analyze multiple samples according to the techniques described in this specification.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 illustrates electrophoresis apparatus 10 of the present invention. In its elementary mode (e.g., FIG. 8 ), apparatus 10 performs single sample studies on chemical or biological matrices having constituents or analytes of interest. But, according to the operating principles shown and described, apparatus 10 can perform multiple analyses by detecting and measuring the presence of a plurality of analytes (for example, three). Suitable and representative analytes may include narcotics, glucose, cholesterol or pharmaceutical drugs that may be present in urine or whole blood, as well as small and large molecular weight substances having simple and complex structures.
As shown in FIG. 1 , apparatus 10 includes platform 12 having side wall 14 . Sample cup 15 is mounted laterally on side wall 14 . A large-bore (150–300 mm in length×500–2000 μm I.D.), non-selective introduction capillary 16 and large-volume (1–3 ml) analyte concentrator 17 connect sample cup 15 to a first input of valve 18 which is coupled, by capillary 20 , to waste container 22 positioned on side wall 14 adjacent to sample cup 15 . In a typical configuration, analyte concentrator 17 comprises a matrix-like assembly of the type shown in U.S. Pat. No. 5,202,010. The collective mass of the matrix is provided by large quantities of microstructures such as beads, platelets, chips, fibers, filament or the like. Individual substrates can be made from glass, plastic, ceramic or metallic compositions; and mixtures thereof. Coated or otherwise deposited onto the microstructures are immobilized analyte-specific antibodies or other affinity chemistries which are suitable for characterizing and separating particular analytes of interest. Representative antibodies include those which act against peptide hormones such as insulin, human growth hormone and erythropoietin. These antibodies are readily available from commercial vendors such as Sigma-Aldrich Co., St. Louis, Mo. and Peninsula Laboratories, Belmont, Calif.
The present invention contemplates a user-friendly, sample preparation step which is designed to eliminate unwanted analytes that occupy binding sites and contaminate the inner walls of capillaries or channels. This procedure will now be described with specific reference to apparatus 10 of FIG. 2 .
A first output of valve 18 is placed in the closed position and a quantity of solution from sample cup 15 is introduced into analyte concentrator 17 . Depending on its pre-selected matrix, analyte concentrator 17 traps, in a non-specific manner, many (up to 100 or more) different analytes, including the analytes under investigation. Sample cup 15 is then replaced by a buffer container (not shown). This replacement step may be accomplished by a rotatable table mechanism of the type described in U.S. Pat. No. 5,045,172. Thereafter, a quantity of buffer is injected through analyte concentrator 17 to remove excess amounts of sample and unwanted sample components. Because valve 18 remains closed during this operation, excess and unwanted samples are passed into waste container 22 .
The remainder of apparatus 10 can now be considered. A second output of valve 18 communicates with transport capillary 24 which, as shown by FIG. 2 , intersects a plurality, here shown as three, of narrow-bore (20–75 μm) separation capillaries 28 , 30 and 32 . Analyte concentrators 34 , 36 and 38 are sequentially stationed at the intersections of transport capillary 24 and separation capillaries 28 , 30 and 32 to trap or bind different analytes of interest.
A first end (the left as viewed in FIG. 1 ) of separation capillary 28 is initially placed in buffer solution cup 40 . In like manner, a first end of separation capillary 30 is placed in buffer solution cup 42 ; and a first end of separation capillary 32 is placed in buffer solution cup 44 . A major portion of separation capillaries 28 , 30 and 32 extend in parallel over the upper surface of platform 12 through detection zone 45 where the analytes respectively present in each of the separation capillaries are identified by an otherwise conventional detector 46 . Separation capillaries 28 , 30 and 32 , which terminate at ground connection 48 , may be secured to the upper surface of platform 12 by holders 49 . Platform 12 can also take the form of an interchangeable cartridge with pre-positioned capillaries and analyte concentrators properly secured and aligned with respect to the optical system. In yet another embodiment, best shown in FIG. 3 , transport channel 24 A and separation channels 28 A, 30 A and 32 A, having uniform and concave shapes, can be engraved, etched or otherwise formed into a glass or plastic microchip using known lithography or other manufacturing techniques. Analyte concentrators 34 A, 36 A and 38 A are disposed at the respective intersections of transport channel 24 A and separation channels 28 A, 30 A and 32 A as previously described.
When the sample preparation step is complete, valve 18 is opened to the main system and a buffer (e.g., sodium tetraborate) is passed through introduction capillary 16 and analyte concentrator 17 . At this time, the analytes of interest are released from analyte concentrator 17 using an eluting solution, along with other analyte constituents present in the sample. The analytes of interest and all the other analytes captured and released by concentrator 17 are passed through transport capillary 24 to analyte concentrators 34 , 36 and 38 which, as described below with reference to FIG. 3 , contain a large quantity of microstructures that are capable of binding different analytes of interest; that is, each of the analyte concentrators 34 , 36 and 38 select and isolate a different one of the analytes under investigation. Excess amounts of sample then pass through the other end of transport capillary 24 to waste container 27 . Transport capillary 24 is subsequently washed with running buffer until unwanted substances are removed.
Separation capillaries 28 , 30 and 32 are filled hydro-dynamically (pressure or vacuum) with an appropriate electrophoresis separation buffer which occupies the entire volume of the capillary or channel. Immobilized analytes on a solid support are stable for long periods of time. As a result, large numbers of analytes can be sequentially separated over time, thereby providing high throughput for the apparatus of the present invention. Separation capillary 28 is first activated by introducing a plug of an appropriate eluting buffer from cup 40 by hydrodynamic (pressure or vacuum) or electrokinetic methods to desorb or elute analytes bound to analyte concentrator 34 . The eluting buffer is immediately followed by a freshly prepared electrophoresis separation buffer present in replacement cup 40 . Then, the power supply connected to cup 40 is activated to begin the process of analyte separation.
As shown in Table 1, with insulin taken as representative, a typical analysis involves the targeted analyte of interest, its corresponding antibody, an appropriate buffer and eluting solution.
TABLE 1
Eluting
Antigen
Antibody
Sep. Buffer+
Solution*
Insulin
Anti-insulin
Sodium
Magnesium
antibody
tetraborate
Chloride or
(pH 8.5)
Ethylene
Glycol
+Concentrations of electrophoresis separation buffer may range from 50 mM to 200 mM.
*Elution of other antigens or haptens may require a different eluting method. Effective eluting buffers include a 2 M solution of Magnesium Chloride and a 25% solution of Ethylene Glycol.
When the initial separation is complete, the next cycle, using separation capillary 30 and analyte concentrator 36 , is performed in a similar manner, i.e., the analyte is eluted from concentrator 36 and then separated by eletrophoresis migration in separation capillary 30 . During these operations, the power supply is connected to one analyte concentrator-separation capillary system at a time.
Separated analytes are then passed sequentially to detection zone 45 where each analyte is recognized and measured by detector 46 using, for example, known UV or fluorescence techniques. In one embodiment of the present invention, a single, bi-directional detector is indexed laterally above platform 12 to detect analytes of interest in separation capillaries 28 , 30 and 32 or separation channels 28 A, 30 A and 32 A. Other sub-assemblies could include a single, fixed detector and movable platform 12 which operates to position separation capillaries 28 , 30 and 32 or separation channels 28 A, 30 A and 32 A beneath the detector. Multiple detectors and movable platforms configured for X, Y and Z indexing are also contemplated.
FIG. 4 illustrates the location of analyte concentrator 34 stationed at the intersection of transport capillary 24 and separation capillary 28 . As shown in FIG. 4 , and in U.S. Pat. No. 5,203,010, porous end plates or frits 50 , which permit fluid flow, are provided in transport capillary 24 and separation capillary 28 to act as barriers for holding microstructures 54 in analyte concentrator 34 .
Alternatively, as shown in FIG. 5 , analyte concentrator 55 can be fabricated by using two constricted areas with no frits at all. Analyte concentrator 55 , in the form of a cross-shaped capillary, has inner diameter 61 and 63 pre-formed in relation to inner diameter 57 of transport capillary 24 and inner diameter 59 of separation capillary 28 .
Analyte concentrator capillary 55 contains a plurality of previously described microstructures 54 which are larger than inner diameters 57 and 59 . They are typically coated with non-specific chemistries such as C-18 or highly specific antibodies or antigens having an affinity for one of the analytes under investigation. Several other well-known chemistries can also be used.
In the embodiment illustrated by FIG. 5 , microstructures 54 are retained or confined in the interior of analyte concentrator 55 by making inner diameter 57 of transport capillary 24 smaller than inner diameter 61 of analyte concentrator 55 . In like manner, inner diameter 59 of separation capillary 28 is smaller than inner diameter 63 of analyte concentrator 55 . For example, inner diameters 57 and 59 may be one-quarter to one-half the size of inner diameters 61 and 63 .
To increase detection sensitivity for a particular analyte, a chromophore may be added to the eluting buffer to elute and tag the bound analyte for the purpose of enhancing the ultraviolet absorptivity, fluorescence, phosphorescence, chemiluminescence or bioluminescence of the analyte as it passes through detector 46 .
In an alternative technique to increase detection sensitivity, additional analyte concentrator 60 may be placed in one of separation capillaries 28 , 30 and 32 , as shown in FIG. 6 . Analyte concentrator 60 has a plurality of microstructures 54 coated with a chromophoric agent or antibody that binds to a portion of a chromophoric agent which increases ultraviolet absorptivity, fluorescence or phosphorescence when bound to a minute quantity of a specific analyte. Frits 62 are located at the input and output of analyte concentrator 60 , and narrow capillary 64 , which intersects with separation capillary 28 , carries a buffer to periodically cleanse microstructures 54 in analyte concentrator 60 after each analysis.
An analyte tagged with a chromophoric agent is more readily identified by the apparatus of the present invention, thereby increasing the sensitivity of analyte detection by as much as 100 times or more. Many different chromophoric agents emit light when they bind a specific functional group to form a product molecule in an electronically excited state.
The alternative embodiment illustrated by FIG. 7 is similar to that shown in FIG. 1 . But, the FIG. 7 embodiment is different because the output ends of separation capillaries 28 , 30 and 32 are connected to each other at the interface with a single outlet capillary 66 which cooperates with on-column detector 86 that senses ultraviolet (UV) or fluorescent energy. The exit position of outlet capillary 66 may also be connected (as shown) to off-column detector 88 which comprises an electrochemical, mass spectrometry, circular dichroism detector or nuclear magnetic resonance detector.
The electrophoresis apparatus of FIG. 7 employs multiple separation capillaries or channels for sample concentration, but only one outlet capillary for sample detection. This coordinated separation by individual capillaries may be sequentially activated and controlled by well-known electronic circuitry. Like the FIG. 1 embodiment, preceding analytes are completely separated and detected before the next separation operation is activated.
The electrophoresis apparatus of FIG. 8 is similar to that of FIG. 7 , but it is adapted to work with multiple samples (here, e.g., three) having a simple or complex component. There is no introduction capillary 16 or sample cup 15 as provided by embodiments of FIG. 1 and FIG. 7 . Separation capillaries 28 , 30 and 32 are equipped with single analyte concentrators 34 , 36 and 38 , respectively. Individual samples are directly and sequentially delivered to separation capillaries 28 , 30 and 32 and the analytes of interest are captured using suitable chemistries as previously described. The capillaries may be washed with buffer until all unwanted substances are removed. Like the FIG. 7 embodiment, separation capillaries 28 , 30 and 32 are activated in series one after the other. When all the analytes are separated in a single capillary, the apparatus begins the next separation cycle. In each of the described embodiments, apparatus 10 provides greater efficiency and higher throughput when compared to prior art devices.
Various modifications and alterations to the present invention may be appreciated based on a review of this disclosure. These changes and additions are intended to be within the scope and spirit of this invention as defined by the following claims. | An electrophoresis apparatus is generally disclosed for sequentially analyzing a single sample or multiple samples having one or more analytes in high or low concentrations. The apparatus comprises a relatively large-bore transport capillary which intersects with a plurality of small-bore separation capillaries. Analyte concentrators, having antibody-specific (or related affinity) chemistries, are stationed at the respective intersections of the transport capillary and separation capillaries to bind one or more analytes of interest. The apparatus allows the performance of two or more dimensions for the optimal separation of analytes. | 6 |
RELATED APPLICATION
This is a continuation-in-part of copending application Ser. No. 541,541, filed Oct. 13, 1983, and now abandoned.
BACKGROUND
1. Field of the Invention
This invention relates generally to protective devices for avoiding impact damage to walls, cabinetry, furniture, chinaware and other objects, and more particularly to transparent self-attaching bumpers.
2. Prior Art
A great variety of bumpers is known for cushioning the impact of swinging doors (particularly including the corners of cabinet doors) and doorknobs, hinged table sections and other panels, rolling carts, and so forth, against walls and furniture. Such bumpers protect the moving surface as well as the stationary surface, and therefore--as an example--are also used for preventing damage to toilet seats when they bump against water closets.
All of these applications, and myriad others, are well known--and have been the object of many commercial "bumper" products. The thrust of design in these products has been to provide bumpers that are sturdy, attachable to the vulnerable surface to be protected (or to the hard surface to be guarded) in a variety of ways, and reasonably attractive.
This last objective has given rise to bumpers in a great variety of shapes, sizes, expensive brushed-metal finishes, decorator colors, and so forth--but by and large has not been satisfied. Bumpers are almost intrinsically unattractive, for several reasons. They are practically by definition something "added on" to a home or office after the decor elements have been settled. They are also conspicuous by virtue of being small, spike-shaped or stubby or knobby objects secured to planar or large-contour surfaces. Attachment is often by screws, which are relatively quite large in relation to the size of each bumper itself.
Even the most esthetic of bumpers, however, are unattractive because they simply do not match the color--or the complex pattern--of the protected or guarded surfaces. They thus appear, at the very least, as non-color-matched "spots" on the wall, wallpaper, or other surface.
Turning to a different field, certain household protective functions have been served by generally transparent articles such as transparent escutcheons for electrical switches. The purpose of such articles, however, has not been to protect against damage due to impacts, but rather generally to protect against soiling of the wall surface near an electrical switch by the oily or dirty hands of users.
Moreover the problem of inconspicuous attachment of such devices is minimized--since the switch itself and its opaque switchplate, behind the transparent escutcheons, are themselves conspicuous interferences with the decor. Too, there is very little added annoyance produced by the means of attachment of the escutcheons to the switchplates--often using the same screws that attach the switchplates to the junction boxes.
In an even more remote field, U.S. Pat. No. 3,687,792 to Charles Ruff discloses a decorative trim strip for automobiles and the like. Ruff's trim strip is composed of a colored ribbon that is coextruded with a generally transparent, colorless plastic bar of trapezoidal cross-section. The ribbon is cemented to the surface to be decorated, and the angles of the plastic bar--along its edges that are elevated above the colored ribbon--are such as to trap any light entering the plastic bar.
Regardless of the angle of entry, in Ruff's invention, light is directed to the colored ribbon; in addition, only light reflected from the colored ribbon can escape the transparent plastic bar. Thus the bar, although actually colorless, appears to have the color of the underlying ribbon. The objective of Ruff's invention is to provide a trim strip that appears to have any one of a great variety of different colors even though it is only the ribbon that is actually colored. Thus the Ruff device is deliberately designed to distort the passage of light in and out of the trim strip.
Now it will be plain that if a piece of Ruff's trim strip were glued over a wall--such as a solid-color wall or a patterned-wallpaper-covered wall--in a home or office, the trim strip would be very conspicuous. It would thus fail to satisfy the needs suggested earlier.
In principle, one might propose to separate the transparent plastic bar that forms the upper portion of Ruff's trim strip from the ribbon portion. One might then propose to use only the plastic bar, in household and office applications such as outlined above.
Ruff, it must be emphasized, suggests no such possibility. His invention is in an entirely different field, and exists for an entirely different purpose, than to guard household or office surfaces inconspicuously, and he does not suggest separating the two components of his invention for any purpose. Without such a suggestion it would not be obvious to make such a modification. Even if this proposed modification of the Ruff invention were made, however, the resulting performance would be quite unsatisfactory for the purposes discussed in this document.
In the case of a uniformly colored wall, the area covered by the plastic bar would have a conspicuously different apparent illumination level than the rest of the wall. This would be a natural consequence of the deliberate design of Ruff's bar to trap all light entering at all possible entry angles and to direct such light to the underlying surface. The surface covered by the plastic bar would appear conspicuously brighter than the surrounding surface.
In the case of a patterned wall surface, dislocations would appear in the image of the pattern as seen through the plastic bar. These dislocations would be due to the abrupt differences in refraction along the distinctly angled edges of the plastic bar, well elevated in front of the wall surface.
To my knowledge there has never been any effort to combine the teachings from these various fields.
SUMMARY OF THE DISCLOSURE
Preferred forms of my invention provide transparent bumpers that are self-attaching to the vulnerable surface to be protected, or to the guarded hard surface against which some other article is to be protected. Self-attachment is provided either by transparent adhesive on the back surface of each bumper, or by configuring the bumper to grip a particular protected or guarded article.
Some of the bumpers of my invention are intended for attachment to generally planar surfaces. The front surface of each such bumper is preferably smooth, and preferably convex outward with a shallow curvature (that is to say, a large radius of curvature). If preferred the forwardmost part of the front surface may be planar, and only the more-peripheral portions shallowly curved. By virtue of this curvature it is possible to provide a fair thickness of resilient material near the center of the bumper, while avoiding the annoyance of an abrupt thick corner or edge at the periphery of the bumper--which otherwise would cause a discontinuity in refraction of light along the edge and thereby call attention to the presence of the bumper. Such a curved surface is preferred, to help hide the edge of the bumper.
If desired, the bumper material and its surface quality can be selected, using principles and techniques well known in the art of plastics engineering and molding, to minimize scattering and specular reflection and refraction while maintaining good resiliency for cushioning against impact. In addition the bumper can be made so that the optical magnification, apparent displacement, and apparent dislocation of the underlying wall pattern are very inconspicuous--or, preferably, quite negligible. These conditions can be met by avoiding sharply angled edges elevated in front of the wall surface, and by proper selection of (1) refractive index of the bumper material, (2) bumper thickness, (3) radius of curvature of the forward surface, and (4) bumper surface angles relative to the underlying wall surface.
(The terms "displacement," "dislocation," "inconspicuous" and "negligible" will be given more precise meanings, for the purposes of this document, in the detailed discussion which follows.)
Such a bumper for use on a generally planar surface has a coating of transparent adhesive at the rear, and is installed simply by being pressed into position. A slick cover sheet over the adhesive, during shipment and storage, protects the adhesive until just before use, as is common with self-adhesive labels, self-adhesive picture mounts, and other articles.
Thus the bumper is at least inconspicuous, whether applied to a surface that is a solid color or to a surface (such as wallpaper) that has an elaborate pattern with many colors. In either case the bumper permits virtually unobstructed view of the guarded or protected surface. At the same time the bumper can protect a wall against a door or doorknob, particularly the handle or corner of a cabinet door; or can protect furniture against hard edges of rolling carts; or can protect a toilet seat against repeated impact with the front of the water closet; and so forth.
Such bumpers for use on generally planar surfaces may also be used on generally cylindrical surfaces or on irregularly curved surfaces, if the radius of curvature of the surface is not too small. For instance, some appliances such as refrigerators have broadly curved door surfaces, and my bumpers can protect these against impact with the corners of other appliances, of furniture, or of walls. Similarly, some homes and offices have round pillars, which--if they are not too small in diameter--can be protected by my bumpers.
Other bumpers in accordance with my invention are specially made to grip particular surfaces or articles to be protected or guarded. In many such cases, the adhesive may be omitted.
For example, many domestic and industrial chores involve moving fragile glassware, chinaware, laboratory instruments, and the like, in close proximity to hard protrusive fixtures such as water faucets. It is a commonplace source of exasperation and wasted resources to break such fragile articles (while washing them, for instance) by striking them inadvertently against such hard fixtures.
Transparent self-attaching bumpers of my invention simply fit over such fixtures--as, for example, slide in a snug fit over the end of a water-faucet nozzle--and grip such fixtures to hold themselves in place. Once thus simply and immediately installed, they cushion the impact of the fragile articles. By virtue of transparency they interfere very little with the appearance of the sink or other use area.
All of the foregoing operational principles and advantages of the present invention will be more fully appreciated upon consideration of the following detailed description, with reference to the appended drawings, of which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic plan view of a bumper in accordance with my invention installed on a wall (shown in cross-section) to protect the wall against impact by a doorknob.
FIG. 2 is an enlarged view of the FIG. 1 embodiment, also in plan (and also showing the wall in section).
FIG. 3 is an elevation of the embodiment of FIGS. 1 and 2, showing a bumper that is generally circular in frontal shape and showing a patterned wall or wallpaper.
FIG. 4 is an elevation of an embodiment that is similar to that of FIG. 3 but has a different frontal shape.
FIG. 5 is an elevation of another embodiment of my invention, installed on a conventional water faucet.
FIG. 6 is an isometric view of the FIG. 5 embodiment detached from the faucet.
FIG. 7 is an isometric view of an embodiment similar to that of FIGS. 5 and 6 but adapted to fit a water faucet of slightly different tip shape.
FIG. 8 is a plan view of an embodiment related to the FIG. 2 embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As shown in FIGS. 1 through 3, a bumper 21 in accordance with my invention is simply pressed against a wall such as 12, in position to intercept a doorknob 14 of swinging door 13--or any other similar hard article that repetitively strikes the wall 12 in generally the same position. The corners and handles of cabinet doors are particularly troublesome in this regard, and my invention is particularly useful in avoiding impact damage due to them. The back surface of the bumper 21 is provided with a layer of transparent adhesive 25, by which the bumper 21 is attached to the wall 12.
The bumper material 22 is itself transparent and resilient. Suitable materials satisfying these criteria, and the others to be specified below, can be provided by a person skilled in the art of plastics engineering and molding.
The forward surface 23 of the bumper 21 is smooth, but not highly shiny; and is convex outward, but with a shallow curvature (that is to say, a large radius of curvature) over almost all of its extent. The index of refraction of the material 22 should be as low as practical.
Because of the surface smoothness and lack of shininess there is very little scattering and very little specular reflection of lights within the room or other area. Consequently the surface color and the pattern 15 of the wall 12 show through the surface 23 as well as through the bulk 22 of the bumper material. Because of the shallow curvature and low index of refraction, there is relatively little refraction, and therefore there is relatively little visual interference with the pattern details 25 of the wall 12. This preservation of wall patterns is particularly beneficial in the case of finely patterned wallpaper.
At the extreme periphery of the bumper 21 there may be provided a relatively more strongly curved "break" 24--a relatively abrupt truncation of the shallow curvature of the surface 23. This change of curvature serves to provide greater strength and uniformity of appearance than would be obtained with a relatively sharp peripheral "edge". As previously mentioned, the convexity of the overall frontal surface 23 of the bumper 21 helps to hide the periphery of the bumper: it brings the periphery, whether a curved break or a sharp edge, very close to the underlying wall surface. Placing the periphery so close to the wall minimizes the possibility of refractive displacements of the underlying pattern, as well as the possibility of noticeable shadows cast by the bulk of the bumper onto the wall.
In short, if the break is sufficiently close to the edge--and therefore very close to the underlying wall surface when the bumper is installed--refractive and umbral effects will be unnoticeable in normal use. To help keep the refractive effects small, even when the break is positioned at the extreme periphery of the bumper 21, the "break" 24 is preferably given some curvature rather than being made a sharply defined edge.
The invention is not limited to generally circular bumpers 21 such as that shown in FIG. 3, but may also be used to provide bumpers of virtually any convenient shape, such as the generally rectangular bumper 21' shown in FIG. 4.
The wall-protective bumpers of my invention preferably produce minimal distortion of patterned or uniform wall surfaces. Ideally the distortion should be negligible or unnoticeable under ordinary viewing conditions. To obtain this result the bumper can be made so that the optical magnification, apparent lateral displacement, and apparent dislocation of the underlying wall pattern are very inconspicuous--or, again ideally, quite negligible.
By "displacement" I mean the distance between the actual position of a point on the wall surface behind the bumper and the image, produced by the bumper, of that same point. By "lateral displacement" I refer to that component of the displacement which is perpendicular to the line of sight. By "dislocation" I mean a break or jump in the appearance of the wall pattern, caused by the bumper.
Magnification of an underlying pattern may be considered "inconspicuous" if, for example, the magnification is less than fifty percent--in other words, if the magnification is less than 1.50 times. Magnification may be considered "negligible" if it is less than, say, fifteen percent--in other words, less than 1.15 times. These values may be appreciated simply by mentally visualizing the effect of looking casually at a small portion of a wallpaper pattern that is magnified by 1.50 or 1.15 times, respectively.
Similarly, lateral displacement may be considered "inconspicuous" if the viewer is perhaps two or more meters (six or more feet) from a wall and the lateral displacement is one centimeter or less. Lateral displacement may be considered "negligible" for the same viewing distances if it is, say, three millimeters or less.
As previously indicated, these various conditions can be met by avoiding sharply angled edges elevated in front of the wall surface, and by proper selection of (1) refractive index of the bumper material, (2) bumper thickness, (3) radius of curvature of the forward surface, and (4) bumper surface angles relative to the underlying wall surface.
More specifically, apparent dislocations of the pattern are made negligible by avoiding sharply angled edges at positions substantially elevated in front of the underlying surface--such as the elevated edges shown in the Ruff patent. Not only abrupt dislocations, however, but also overall apparent displacement of a continuous sort, can be conspicuous.
As to apparent lateral displacement, it is to be understood that the amount of such displacement depends upon the angle at which the person's gaze (the line of sight) lies relative to the "normal". (In geometry a "normal" is a line drawn perpendicular to a surface.) In addition, the conspicuousness of the lateral displacement depends upon the distance of a viewing person from the bumper.
When the viewer observes the bumper at a very large angle from the normal, the amount of refractive displacement (as well as the amounts of scattering and reflection) can be quite large--particularly if the dimensions of the bumper are unfavorable.
Moreover, at very large viewing angles the bumper can actually obscure portions of the wall pattern. This effect too can be minimized by optimizing the bumper dimensions.
It is not strictly necessary to reduce the lateral displacement and other effects to an insignificant level for very large viewing angles. In practice, people do not ordinarily direct their gaze in a purposeful manner to particular areas of a wall, at very large viewing angles relative to the wall. Moreover, even if they do so, the overall visual angle subtended by one of my bumpers is made smaller by the cosine effect, while the same effect renders the pattern details of the wall less distinct.
Hence as a practical matter it is reasonable to configure one of my bumpers to perform well only at viewing angles less than, say, sixty or seventy degrees. This point will be explored further below.
The following equation shows the approximate relationship between the lateral component w of the optical displacement produced at any point on a curved frontal surface of one of my bumpers: ##EQU1## in which h is the height of the bumper-surface point in front of the patterned wall surface, X the viewing angle relative to the normal, Y the bumper-surface angle at the point of interest relative to the surface of the underlying wall, and n the index of refraction of the bumper material.
This equation may be simplified for points at which the bumper frontal surface is parallel to the underlying wall surface--such points as will typically be found at, for example, the apex of a spheroidal or like bumper--by setting Y equal to zero, so that: ##EQU2##
Now I will define F as the factor appearing in parentheses in the equation above, and the equation may be rewritten w p =h·F. This equation represents an important case, since the parallel-surface point produces the largest value of displacement anywhere on the surface. This is true because the height h is greatest at the parallel-surface apex. The effect of larger surface angles Y (at points on the frontal surface at the far side of the bumper from the viewer) tends to be compensated by the effect of the accompanying smaller heights h above the wall surface.
Although "inconspicuous" bumpers can be made allowing apparent displacements w p as large as one centimeter, I prefer to make bumpers in which the lateral displacement w p will be "negligible"--three millimeters or less. It develops that this can be easily accomplished even for high refractive index. To find the maximum permissible apex height h max for any particular value of apparent displacement w p at the apex, the simplified equation above is solved for h in terms of w p ,
h=w.sub.p /F,
and the permissible displacement value is inserted for w p . Of course the refractive index must also be supplied.
The factor F varies with viewing angle X and refractive index n in a way that is somewhat surprising and useful for purposes of practicing my invention:
______________________________________X F(degrees) n = 1.3 n = 1.45 n = 1.65______________________________________ 0 0.00 0.00 0.0010 0.04 0.05 0.0720 0.09 0.11 0.1430 0.14 0.18 0.2240 0.21 0.26 0.3250 0.30 0.37 0.4360 0.42 0.49 0.5670 0.58 0.65 0.7080 0.78 0.82 0.8690 1.00 1.00 1.00______________________________________
This tabulation shows that F cannot exceed 1.00, regardless of the refractive index. This means that the lateral displacement w p =h·F cannot exceed the bumper thickness h, regardless of index.
From these facts it should now be apparent that one very simple way to configure my transparent bumpers to prevent the lateral displacement from exceeding any desired value is to make the thickness of the bumpers equal to that lateral-displacement value. In other words, we can use the value F max =1.00, and find h max =w p /F max =w p . If the bumpers are ten millimeters thick, the lateral displacement will not exceed ten millimeters--and will be "inconspicuous" as defined above. If the bumpers are three millimeters thick, the lateral displacement will not exceed three millimeters--and accordingly will be "negligible."
For reasonable cushioning effect it is preferable to have at least a 21/2-millimeter thickness of plastic (varying with material, as elsewhere noted). This condition is easily satisfied within the constraint presented above for "negligible" lateral displacement.
If better cushioning is desired (or if for any other reason it is considered very important to use a thicker bumper), and in particular if this consideration is more important than the appearance of the wall pattern at very large viewing angles, then as previously suggested the performance of the bumper at large viewing angles can be sacrificed slightly to obtain greater thickness. In this connection it is possible to take advantage of the variation of F with refractive index at intermediate viewing angles, to select a material whose index of refraction yields sufficiently low lateral displacement w p =h max ·F at some intermediate angle such as sixty or seventy degrees.
As indicated earlier, the importance of extreme viewing angles may be discounted by virtue of the cosine effect on the visibility of wall-pattern details, in combination with the normal casual viewing habits of people generally. At a horizontal viewing angle of seventy-five degrees the overall visual angle subtended by the width of a bumper is only about one-quarter the actual width of that bumper (though the apparent height of the bumper remains the true height), making the entire bumper reasonably inconspicuous in the usual sense of that word.
By reference to the tabulation presented above it can be seen that h max may be kept between, for example, w p /0.70 (at seventy degrees, n=1.65) and w p /0.42 (for sixty degrees, n=1.3). These values correspond to 1.42 w p and 2.38 w p respectively. Summarizing, and including some additional intermediate values for sixty and seventy degrees:
______________________________________dis- maximumplace- "important" maximum bumper heightment --w.sub.p view angle (mm)effect (mm) X (degrees) n = 1.3 n = 1.45 n = 1.65______________________________________"incon- 10 60 24 20 18spicuous" 70 17 15 14 90 10 10 10"negli- 3 60 7 6 5gible" 70 5 5 4 90 3 3 3______________________________________
As seen from this tabulation, even for refractive index of 1.65 the bumper may be eighteen millimeters (1.8 centimeter) thick if the greatest viewing angle considered "important" is sixty degrees. At index 1.30, however, the bumper may be twenty-four millimeters (2.4 centimeters) thick for the same viewing angle; thus there is an advantage to use of material with lower index, when trading off viewing angle for thickness.
Now turning to the matter of magnification, it will be helpful first to explore the dimensional requirements if the bumper has a spheroidal front surface. For simplicity's sake it also will be assumed that the overall diameter of the bumper is just large enough to effectively catch a doorknob--say, one inch (21/2 centimeters). In addition it will be assumed that the peripheral portion of the surface has a "break" about 1.5 millimeter tall--in other words, that the spheroidal surface terminates 1.5 millimeter away from the underlying wall surface, when the bumper is installed.
Under these assumptions the radius of curvature of the spheroidal surface must be roughly (in centimeters): ##EQU3##
Concentrating on the values in the preceding tabulation, and recalling that w p is three millimeters for "negligible" displacement and ten millimeters for "inconspicuous" displacement,
______________________________________dis- maximumplace "important" radius of curvature --Rment --w.sub.p view angle (cm)effect (mm) X (degrees) n = 1.3 n = 1.45 n = 1.65______________________________________"incon- 10 60 1.5 1.4 1.3spicuous" 70 1.3 1.3 1.3 90 1.3 1.3 1.3"negli- 3 60 1.7 1.9 2.2gible" 70 2.3 2.7 3.0 90 5.3 5.3 5.3______________________________________
This summary tabulation shows that allowing the apparent displacement to be merely "inconspicuous" rather than fully "negligible" is not necessarily more desirable in terms of radius of curvature. The ten-millimeter apex displacement w p seems to lead to a maximum permissible height h max of ten to twenty-four millimeters; but if these height values are actually used, the corresponding radius of curvature--for a 21/2-centimeter overall diameter--becomes extremely sharp. The radius is 1.3 to 1.5 centimeters, depending upon index of refraction and viewing angle.
A similar result appears for the "negligible" displacement figures, if one attempts to take actual advantage of the intermediate-angles tradeoff: in these cases the radius goes to 1.7 to 3.0 centimeters.
The resulting magnification values are unacceptable. The corresponding magnification M of the wall pattern as viewed along the normal to the wall (that is to say, looking straight toward the wall; X=0) may be calculated from-- ##EQU4##
For the same conditions in the two preceding tabulations, the magnification is:
______________________________________dis- maximumplace- "important"ment --w.sub.p view angle magnification --Meffect (mm) X (degrees) n = 1.3 n = 1.45 n = 1.65______________________________________"incon- 10 60 1.60 1.87 2.20spicuous" 70 1.45 1.61 1.81 90 1.21 1.30 1.41"negli- 3 60 1.11 1.11 1.11gible" 70 1.05 1.06 1.06 90 1.01 1.02 1.02______________________________________
Looking first at the upper half of this tabulation, the conditions (namely, bumper height of ten millimeters) previously identified with so-called "inconspicuous" lateral image displacement produce very large values of magnification. These values are as high as 2.20, which represents an increase of one hundred twenty percent in apparent size. Even the smallest value of magnification in the upper half of the table is 1.21, or a twenty-one percent increase. This value, and the other values given for maximum important viewing angle of ninety degrees do fall in the range of magnification values previously identified as "inconspicuous," but they are not in the "negligible" range.
Most of the other magnification values in the upper half of the table are likely to make the pattern seen through the bumper very conspicuously different from the pattern adjacent to the bumper. Furthermore, the curvature is so strong that conspicuous reflective effects are likely to appear, and in fact the bumper will protrude rather prominently from the wall.
To avoid these characteristics it becomes necessary either to make the overall diameter considerably larger, so as to spread the height over a larger lateral dimension and thereby reduce the magnification, or simply to reduce the height below the maximum value that was found to be permissible when considering only displacement.
Using the former option, the height and lateral dimension combine to produce very large, bulky articles which are correspondingly expensive to manufacture, stock, package and distribute. These articles are also unnecessarily large in terms of the desired wall-surface protection. (Moreover, as will be recalled, image displacement is only "inconspicuous" rather than "negligible".) The latter option is far preferable, since it provides lower costs and better apparent image displacement. Cushioning is adequate with suitable choice of materials.
The best solution is to reduce the height to the values shown earlier for "negligible" displacement. Referring to the last tabulation above, the magnification is only 1.01 to 1.11--i.e., a size increase that is between one and eleven percent.
It will be understood, however, that my invention encompasses all such parameter combinations in the so-called "inconspicuous" category, as well as the so-called "negligible" cases.
Now in view of the spheroidal-surface cases discussed above it should be understood that irregularly shaped bumper frontal surfaces may be much more difficult to analyze, or may be straightforwardly comprehended from the analysis already presented, depending on the degree of irregularity.
For example, as shown in FIG. 8 a bumper 321 with a curved outer portion 323c leading upwardly to an essentially planar middle portion 323p will produce maximum displacement in its planar middle region. The displacement so produced in the planar region can be calculated from the apex-displacement equation already stated. In that same central region the magnification will be zero, by virtue of the planar surface. If the curved outer part 323c is circular in cross-section, the magnification in that region can be found from the magnification equation above--considering the outer part 323c as if it were part of an entirely spheroidal bumper of the same radius of curvature. (This magnification of course occurs only in the direction of the curvature.) The overall diameter of the bumper, however, will be larger by virtue of the planar portion 323p. It will be understood that a bumper of the sort described in this paragraph need not be circular in overall shape, but rather may be shaped as at 21' in FIG. 4.
Bumper curvature in the curved portion 323c of FIG. 8--and indeed at any part of the frontal surface of any of the bumpers in FIGS. 1 through 4--may be ellipsoidal, parabolic, or simply "gradually tapered" without any particular geometric definition. In any event the local curvature and height at a particular surface point may be used to find the apparent displacement and magnification at that point for purposes of optical-performance evaluation.
Using good-quality transparent plastic my invention should produce no conspicuous discontinuity of apparent illumination--as between the underlying wall surface that is covered by a bumper and the adjacent wall surface that is not so covered. An exception may arise in a very thin annular area at the extreme periphery, immediately adjacent to the underlying wall surface. Otherwise lighting discontinuity should be inconspicuous--in photographic terms well under a half-stop (a factor of about 1.4). With ordinary care in design the lighting discontinuity should be negligible--less than a quarter-stop (a factor of 1.2).
For comparison, the Ruff plastic trim strip has, as it appears from his drawings, between approximately thirty-seven and fifty-six percent more light-collecting surface than underlying surface to be illuminated. Assuming isotropic illumination, the apparent illumination of the wall area behind one of his clear plastic strips would be 1.37 to 1.56 times brighter than the uncovered wall area.
Another embodiment of my invention appears in FIGS. 5 and 6. In FIG. 5 the bumper 121 fits over the tip or filter section 113 of an ordinary faucet or water spout 112. The tip section 113 is here assumed to be generally cylindrical; hence the internal surface 125 of the bumper 121 is also generally cylindrical. The outer surface 123 may if desired be generally conical as shown, to minimize mechanical interference with activities nearest the tip of the faucet. If preferred to yield even better impact guarding, however, the outer surface 123 may instead be generally cylindrical.
The top and bottom surfaces may be generally planar, normal to the axis of the faucet tip, as suggested at 124 in FIG. 6. As will be apparent, many other shapes are also practical.
A variant of the embodiment of FIGS. 5 and 6 appears in FIG. 7. Here the bumper is made to fit over a faucet tip that is tapered or generally conical; consequently the internal surface 225 of the bumper too is correspondingly tapered or generally conical.
It is to be understood that all of the foregoing detailed descriptions are by way of example only, and not to be taken as limiting the scope of my invention--which is expressed only in the appended claims.
For the purposes of the appended claims the term "consumer" and the term "home" or "household" shall be understood to encompass, respectively, "office worker" and "office". | Like conventional bumpers, these transparent self-attaching bumpers for household and office use protect walls, cabinets, furniture, chinaware and other objects from damage due to impacts. By virtue of transparency and other optical properties, however, they avoid the conspicuous "spots" on the protected or guarded surfaces which conventional bumpers constitute. These bumpers are sufficiently low in optical distortion (ideally they have negligible magnification, displacement, and discontinuity), as well as in optical scattering and reflectance, to be extremely inconspicuous even when placed over distinctly patterned surfaces. These bumpers are made self-attaching either by a coating of adhesive--which is also transparent--or by forming the bumpers themselves to grip particular shaped surfaces to be protected or guarded. | 4 |
BACKGROUND OF THE INVENTION
The invention relates to a starter for an internal combustion engine. By way of example, one such starter is described in the Kraftfahrtechnischen Taschenbuch (Motor vehicle manual) produced by Bosch, 25 th edition, page 986, in the form of a pre-engaged Bendix starter, which is operated via a so-called pull-in relay. This relay carries out the pulling-in functions, that is to say engaging the pinion of the starter motor in the toothed rim on an internal combustion engine, and switching the main current of the starter motor. In this case, a distinction can be drawn between two possible processes when the pinion engages in the toothed rim: in about 20%-30% of switching operations, one tooth of the pinion engages in a gap in the toothed rim, while, in approximately 70%-80% of the switching operations, one tooth of the pinion strikes a tooth on the toothed rim during engagement, and the engagement process must be assisted by an engagement spring. This known starter design admittedly requires only a single relay and can therefore be produced at relatively low cost, but on the other hand it results in very difficult working conditions for the switching process for the high motor current on the switching contact which connects the motor windings to the voltage source. Particularly in the case of partially discharged batteries and as the mechanical wear on the engagement parts increases, the dynamic response when switching on the main starter current can decrease to such an extent that the contacts are welded by arcs which occur during the switching process. On the other hand, if the pinion engages directly in the engine toothed rim, the dynamic response of the switching process and the contact wear resulting from it may possibly be high, depending on the design of the starter, when starting from an initial tooth-in-gap position.
In order to improve the switching-on process, particularly in the case of high-power starters, it is also known from the abovementioned reference for the motor current to be switched on in two stages in so-called pre-engaged starters wherein, in a first stage, the pinion of the starter is moved against the toothed rim of the engine, and the armature of the starter motor is at the same time fed with a reduced current, as a result of which the armature and, with it, the pinion, rotate during the engagement process, thus simplifying the engagement process. The engagement mechanism is in this case provided with a ratchet which closes a further switching contact of the relay and, via this, the main current circuit of the motor, only at the end of the engagement process of the pinion. This allows the engagement process and the switching of the main current of the motor to be carried out in two separate processes, but the design of the pull-in relay is more complex and more susceptible to defects, from the mechanical and electrical points of view.
SUMMARY OF THE INVENTION
The starter according to the invention, has the advantage that the processes for engagement of the pinion on the one hand and the switching of the motor current on the other hand are completely decoupled by the use of separate means for this purpose, in particular by the use of separate relays, in which case, the types of relay can be optimally matched to the respective process steps. However, it is also possible to use suitable semiconductor components, preferably transistors or GTO (Gate Turn Off) thyristors, for switching relatively high currents for all of the switching means, or for individual switching means. In particular, this makes it possible to completely separate the switching function for the high main motor current during starting of the internal combustion engine from the engagement process, thus avoiding reactions from the engagement dynamics on the contact system of the relay. The speed at which the contacts close is in this case independent of the engagement situation.
It is particularly advantageous for the switching relay in the main circuit of the starter motor to be activated by the engagement relay itself at the end or shortly before the end of the engagement movement, and in this case for the starter motor to be connected directly to the voltage source. With little additional complexity, this results in exact interaction between the engagement movement of the pinion and the process of switching on the main starter current at the end of the engagement movement. The engagement relay is for this purpose expediently equipped with a holding winding and a separate pull-in winding, which jointly operate a switching contact for activation of the switching relay. The holding winding and the engagement winding are preferably seated on the same relay core, and are in this case selectively switched in the same sense or in opposite senses. If they are switched in the same sense, the required total flux is achieved with a smaller number of turns and/or a lower excitation current while, if the fluxes are opposite, the winding with the lesser flux can be used to damp the switching process. The numbers of turns and the excitation currents for the holding winding and the pull-in winding are in this case expediently chosen such that the holding winding produces the switching process of the engagement relay with a large number of turns and an adequate excitation current, while the pull-in winding is equipped with considerably fewer turns, but carries a considerably higher excitation current, which is sufficient to easily rotate the armature during engagement.
One particularly simple and cost-effective circuit design is obtained by current being passed through the starter motor in a single stage, in which case the pull-in winding of the engagement relay is connected in series with a series winding of the starter motor, as a bias resistance, and both windings of the engagement relay jointly switch a make contact, via which current is passed to the winding of the switching relay, and the starter motor is supplied with the entire motor current at the end of the pull-in movement of the engagement relay. As is known, an arrangement such as this requires an engagement spring which, in conjunction with a steep-pitched thread, in particular when the pinion and the toothed rim are in a so-called tooth-on-tooth position, assists the engagement process, before suddenly switching on the main current for the motor.
A particularly protective engagement process is achieved by passing current through the starter motor in two stages in a manner which is known in principle, in which case, in a first switching stage, a limited rotation current for the starter armature flows via a normally-closed contact and the pull-in winding of the engagement relay. In a second stage, current is subsequently passed through the separate switching relay via a make contact of the engagement relay at or shortly before the end of the pulling-in movement of the relay armature, and the full motor current is supplied to the starter motor. In this case, the two separate relays can be optimally designed in accordance with the different requirements.
BRIEF DESCRIPTION OF THE DRAWINGS
Further details and advantageous refinements of the invention will become evident from the dependent claims and the description of the exemplary embodiments, which will be explained in more detail in the following description and are illustrated in the drawings, in which:
FIG. 1 shows an outline illustration of a pre-engaged Bendix starter with a series winding,
FIG. 2 shows a circuit diagram of a conventional embodiment of a starter through which current is passed in a single stage,
FIG. 3 shows a circuit diagram of an embodiment according to the invention of a starter through which current is passed in a single stage,
FIG. 4 shows a first circuit diagram of an embodiment according to the invention of a starter through which current is passed in two stages,
FIG. 5 shows a second circuit diagram of an embodiment according to the invention of a starter through which current is passed in two stages,
FIG. 6 shows an outline illustration of the spatial arrangement and connection of a starter according to the invention with an engagement relay and a switching relay, and
FIG. 7 shows an outline illustration of the spatial arrangement and connection of a starter as shown in FIG. 6 , with an additional pilot control relay for passing current through the engagement relay.
DETAILED DESCRIPTION
FIG. 1 schematically illustrates the mechanical design of the starter 10 according to the invention, in the form of a pre-engaged Bendix starter for an internal combustion engine. The starter 10 has a starter motor 12 whose output drive shaft 14 has a steep-pitched thread 16 which interacts with a corresponding female thread in a driver shaft 18 . Alternatively, the output drive shaft 14 is driven via an epicyclic gearbox, which is connected in between, but is not illustrated. The driver shaft 18 is firmly connected to the outer ring of a freewheeling ring 20 , whose inner ring is fitted with a pinion 22 . The pinion 22 and the freewheeling mechanism 20 are mounted on the output drive shaft 14 such that they can move axially as far as a stop 24 . The pinion 22 in this case engages in a toothed rim 26 of an internal combustion engine, which is not illustrated. The axial movement takes place with the aid of a relay arrangement 28 , which is illustrated in detail in the following figures and acts on the freewheeling mechanism 20 via a direction-changing lever 29 and an engagement spring 32 . A battery is used as the voltage source 34 for the arrangement; the negative pole 31 of the battery is connected to ground, and its positive pole 30 is connected on the one hand directly and on the other hand via an ignition/starter switch 36 to the relay arrangement 28 . A series winding 38 is fed via the relay arrangement and is connected to ground via brushes 40 , 42 and via the commutator 44 of the motor. The armature of the starter motor 12 is annotated 46 , and its stator is annotated 48 .
FIG. 2 shows a circuit diagram of a conventional embodiment of a starter through which current is passed in a single stage. In this case, the positive pole 30 of the voltage source is connected to an engagement relay 49 , on the one hand via the ignition/starter switch 36 and a connection 50 , and on the other hand directly. This engagement relay 49 contains a holding winding 52 and a pull-in winding 54 , which are wound in the same sense, are wound on the same core, and are both connected at one winding end to the connection 50 . The other winding end of the holding winding 52 is connected to the negative pole 31 and to ground, and the corresponding other winding end of the holding winding 54 is connected to the negative pole 31 and to ground via the series winding 38 and the armature 46 of the starter motor 12 . The holding winding and the pull-in winding jointly operate a make contact 56 in the engagement relay 49 , via which the starter motor 12 is connected directly to the positive pole 30 as soon as the relay armature has pulled in entirely or virtually entirely, and the pinion 22 has engaged in the toothed rim 26 .
The holding winding 52 and the pull-in winding 54 in this known arrangement together carry out the task of engagement of the pinion 22 in the toothed rim 26 on the internal combustion engine, and at the same time the function of switching the main current for the starter motor 12 . If, during this process, a tooth of the pinion 22 meets a gap in the toothed rim 26 , then only a small amount of force is required for engagement, and the dynamic response during switching of the contact 56 is relatively high. On the other hand, the dynamic response during switching of the contact 56 is very low when, during engagement, a tooth on the pinion 22 strikes a tooth on the toothed rim 26 , as a result of which the engagement spring 32 , as shown in FIG. 1 , must also be stressed during engagement, and only a small amount of energy is available for operation of the make contact 56 . In consequence, relatively long-lasting arcs and welding can occur, which adversely affect the operation of the starter, at least in the long term.
FIG. 3 shows the circuit diagram of an embodiment according to the invention of a starter through which current is passed in a single stage, and which overcomes the difficulties described above. In principle, with an engagement relay 57 and its connection to the DC voltage power supply system 30 , 31 , the design of the circuit arrangement corresponds to that in FIG. 2 , but in this arrangement the relay contact 56 does not carry out the switching function for the high motor current, but only for passing current through the winding 58 of a switching relay 60 , which then switches the motor current via its make contact 62 . In addition, this arrangement operates in only one stage, with the pinion 22 engaging in the toothed rim 26 in the same way as in the arrangement shown in FIG. 2 , and with the motor current being switched on completely at the end or shortly before the end of the engagement movement of the pinion 22 . In contrast to the arrangement shown in FIG. 2 , in addition to the engagement work for the pinion 22 , however, the engagement relay 57 only has to operate the lightly loaded contact 56 , and the actual process of switching on the motor current is carried out by the switching relay 60 , as a result of which the functions of engagement and switching are completely separate, and the engagement process does not cause any reaction on the contact system of the switching relay 60 .
FIG. 4 shows a circuit arrangement for passing current through a starter motor 12 in two stages. In this case, instead of the engagement relay 57 for passing current in a single stage, as shown in FIG. 3 , there is an engagement relay 64 with a normally-closed contact 66 and a make contact 68 . The fixed connections of the contacts 66 and 68 can in this case be connected in parallel via a pilot control relay 70 to the positive pole 30 , with one end of the relay winding being connected to the negative pole 31 and to ground, and the other end being connected via the connection 50 and the ignition/starter switch 36 to the positive pole 30 of the DC voltage power supply system. The holding winding 52 of the engagement relay 64 is likewise connected via the pilot control relay 70 to the positive pole 30 and to the negative pole 31 of the DC voltage power supply system.
In this embodiment, the two windings 52 and 54 of the engagement relay 64 are wound in opposite senses, with the holding winding 52 having a considerably greater number of turns than the pull-in winding 54 and being excited with a sufficiently high current in order to carry out the engagement process for the pinion 22 on its own, despite the flux in the opposite direction in the pull-in winding 54 . In this case, the pull-in winding 54 advantageously damps the dynamic response of the engagement movement, and at the same time supplies a sufficiently high excitation current to the series winding 38 of the starter motor in order to rotate this slightly, and to simplify the engagement process, or to allow the engagement process. In this arrangement, an engagement spring can additionally be used in order to assist the engagement process.
Once again, the current flow through the starter motor 12 is provided by the switching relay 60 , independently of the operation of the engagement relay 64 . For this purpose, current is passed through the winding 58 of the switching relay 60 at the end or close to the end of the switching movement of the engagement relay 64 , by closing its make contact 68 and opening the normally-closed contact 66 , such that the switching relay 60 is supplied with its predetermined operating current via its make contact 62 , without the engagement process adversely affecting the starter motor 12 . Because the normally-closed contact 66 has been opened, there is no current through the pull-in winding 54 of the engagement relay 64 , while its holding winding 52 remains excited until the ignition/starter switch 36 opens, and thus ensures that the starting process is continued.
The use of a pilot control relay 70 for the operation of the circuit arrangement as shown in FIG. 4 is not absolutely essential, and current can also be passed through the engagement relay 64 directly via the ignition/starter switch, analogously to the circuit arrangement shown in FIG. 3 . On the other hand, in the first current-flow phase, the motor current via the pull-in winding 54 is in the order of magnitude of up to 200 A, which means that it is expedient to use a pilot control relay to bypass the ignition/starter switch 36 in the first stage of the current flow, at least for high-power starting motors.
FIG. 5 shows a variant of the circuit arrangement from FIG. 4 , which differs from the previously described embodiment in that the excitation current for the winding 58 of the switching relay 60 does not flow via the pilot control relay 70 , but is tapped off directly from the supply line to the positive pole 30 of the voltage source. This admittedly has the disadvantage that an additional connection is required between the engagement relay 64 and the switching relay 60 , but on the other hand it reduces the magnitude of the current via the engagement relay 64 , and there is therefore no need for the pilot control relay 70 , at least for relatively small types of motor. All the other functions of the circuit arrangement shown in FIG. 5 correspond to those in FIG. 4 , and do not need to be explained again.
In order to explain illustrations in FIGS. 6 and 7 , FIGS. 3 to 5 show additional connection points with the reference symbols 50 i , 50 k , 50 m and 50 n . In this case, the connection point 50 i is connected to the fixed connection of the relay contact of the pilot control relay 70 , the connection point 50 k is connected to the winding connection of the switching relay 60 , the connection point 50 m is connected to one connection, and the connection point 50 n is connected to the other connection, of the make contact of the engagement relay 57 , or 64 . These reference symbols make it easier to interpret the illustrations in FIGS. 6 and 7 , in which case the switching contacts which are normally in practice in the form of double contacts or have a contact plate, are likewise illustrated schematically.
FIG. 6 shows the design configuration of a starter according to the invention with a single-stage current flow corresponding to FIG. 3 . In this case, the starter motor 12 , the engagement relay 57 and the switching relay 60 form one unit 72 , in which case either both relays 57 and 60 or one of them are or is integrated permanently in the housing of the starter motor 12 , or is or are detachably connected to it. The internal design of the engagement relay 57 , of the switching relay 60 and of the starter motor 12 are indicated symbolically by the respective connection points. For example, the engagement relay 57 receives its start signal via an external connection from the ignition/starter switch 36 , as a result of which the make contact 56 is closed, and the connection points 50 m and 50 n are connected to one another for excitation of the relay.
In the switching relay 60 , the positive pole 30 is connected via the make contact 62 to the connection point 45 on the relay, and this is externally connected to the starter motor 12 and, via its series winding 38 , to the negative pole 31 , and to ground.
FIG. 7 shows the spatial arrangement of a starter according to the invention through which current is passed in two stages, corresponding to FIG. 4 or 5 . In this case, the pilot control relay 70 , the engagement relay 64 , the switching relay 60 and the starter motor 12 form one unit 74 . Once again, the relays 70 , 64 and 60 are selectively integrated individually or jointly in the housing of the starter motor 12 , or are detachably connected to it. The illustration of the connection points and of the contacts corresponds to FIGS. 4 and 5 , which differ only in the current supply to the make contact 68 in the engagement relay 64 . The connection 50 n in the engagement relay 64 is in this case selectively connected either to the connection point 50 i on the pilot control relay 70 , or directly to the positive pole 30 of the voltage source. | The invention relates to a starter ( 10 ) for an internal combustion engine, comprising a starter motor ( 12 ) which can be coupled to the internal combustion engine by means of a pinion ( 22 ), and a device for engaging the pinion ( 22 ) in a gear rim ( 26 ) of the internal combustion engine and connecting the starter motor ( 12 ) to a DC voltage supply system ( 30, 31 ). In order to disconnect the sequence of operations, the device has separate means, in particular separate relays ( 57, 64; 60 ), for engaging the pinion ( 22 ) on one hand and turning on the starter motor on the other when the internal combustion engine is started, thus preventing reactions of the engagement dynamics on the contact system when the motor current is switched. | 5 |
FIELD OF THE INVENTION
The present invention is directed generally to a vehicle door unlocking device. More particularly, the present invention is directed to a vehicle door unlocking device operable from the exterior of the vehicle to elevate the interior door lock rod. Most specifically, the present invention is directed to a vehicle door unlocking device having a door lock knob ensnaring loop formed of two flexible wires. The wires are supported and guided by a generally rigid guide member which is generally arcuate in shape and is insertable between a vehicle window or window frame and a cooperating resilient seal element or the like. The two flexible wires can then be remotely manipulated from the outside of the vehicle in such a manner that a loop that they form can be enlarged and placed over a door lock actuating knob or rod, and then tightened about the rod or knob. Once the flexible wire loop has been drawn tight about the door unlocking rod, the vehicle door unlocking device can be moved in an appropriate manner to unlock the vehicle's door.
DESCRIPTION OF THE PRIOR ART
In numerous situations the need arises to unlock a vehicle door when either the vehicle's owner, the vehicle's keys, or both are not present. Police officers, security officers, fire fighters and the like all are frequently faced with a situation where access to a vehicle must be obtained in a rapid manner. While such access can be accomplished either by breaking a window or in another similar destructive manner, this is not a satisfactory solution. Various other personnel, such as parking lot attendants, tow truck operators, locksmiths and various officials have a legitimate need to be able to obtain access to locked vehicles. Such access in situations of this nature should be obtained in a manner which is not harmful of the vehicle. Even though the vehicle's owner may have parked in an improper area, may have locked his vehicle when he should not have, or may have lost or misplaced his keys, he will expect that the person obtaining access to his car do so in a non-destructive manner.
Various prior art devices are generally known and are available for opening locked vehicle doors. Perhaps the most common of these devices is the so-called "slim jim" which is typically in the form of a long flat strip of spring steel having various hooks or slots formed at one end. This device is inserted down into the interior of the door and is then manipulated to unlock the door. Several drawbacks are inherent with this device. Initially, the user cannot actually see what he is doing with the end of the steel strip that has been inserted down inside the door. Thus the success of the attempted unlocking varies with the skill of the operator. Another problem with this type of tool is that it is somewhat large and cumbersome. It cannot be folded, collapsed or otherwise reduced in size when it is not being used and is somewhat cumbersome to transport or store. Additionally, many newer cars with internal door reinforcing beams cannot readily be unlocked using this device.
Most vehicle owners have probably been in the situation where they have inadvertently locked their keys inside their vehicle or have misplaced them. Attempts to unlock the vehicle are often made by using a wire coat hanger that has been reformed by being manually bent to have a loop in one end. This looped end is then inserted between the window and frame or between the door and frame and the coat hanger is manipulated to attempt to place the loop over the door locking knob or rod. Such crude devices are sometimes successful but often are not and quite frequently damage the vehicle. Various other prior art devices are basically refinements of the bent coat hanger but still suffer the same problems as well as also being cumbersome or bulky.
Vehicles are frequently equipped with electric door locks or with door lock actuating rods that do not have an enlarged free end. In the former case, the looped coat hanger type of unlocking device is not sufficiently strong to operate an electrically locked door while in the latter situation, the hook or loop, which is not adjustable in size once it has been inserted into the vehicle, merely slides up over the free end of the door lock actuating knob. In either situation, the presently available vehicle door unlocking devices have proven unsatisfactory.
It will be apparent that a need exists for a vehicle door unlocking device which overcomes the disadvantages of the prior art devices. The device should be small, able to be operated by the infrequent user, not damaging to the vehicle, and able to unlock various door configurations. The vehicle door unlocking device in accordance with the present invention, as will be discussed shortly, satisfies these requirements in a manner far superior to prior art devices.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a vehicle door unlocking device.
Another object of the present invention is to provide a vehicle door unlocking device utilizing flexible wires.
A further object of the present invention is to provide a vehicle door unlocking device utilizing a door lock rod encircling loop.
Yet another object of the present invention is to provide a vehicle door unlocking device in which the flexible wires are manipulatable exteriorly of the vehicle.
Still a further object of the present invention is to provide a vehicle door unlocking device having a rigid, arcuate guide sleeve which is positionable between the vehicle window and frame.
Even yet another object of the present invention is to provide a vehicle door unlocking device which is small, compact and inexpensive.
Yet still a further object of the present invention is to provide a vehicle door unlocking device that is simple to operate and which will not cause damage to the vehicle.
As will be discussed in greater detail in the description of the preferred embodiment, which is set forth subsequently, the vehicle door unlocking device in accordance with the present invention utilizes a pair of flexible elongated wires which pass through a rigid, generally arcuate guide sleeve. The wires are formed into an adjustably sized loop at a first, interior end, and are provided with manipulating handles at a second, exterior end. The guide sleeve has a loop protecting insertion tip which is shaped to facilitate insertion of the sleeve from the exterior of a vehicle into the interior of the vehicle as by insertion of the sleeve between the vehicle window glass and resilient seal or between the door frame and seal. Once the inner end of the guide sleeve has been placed within the vehicle, the flexible wires can be manipulated from outside of the vehicle to manipulate the wires and loop interiorly within the vehicle and into position about the door's unlocking rod. The loop may then be tightened by pulling one of the exterior wires. This secures the loop about the rod or knob so that it can be pulled upwardly by further tension being applied to the wire, by elevation of the wire guide sleeve, or by both to raise the knob and thereby unlock the door.
In contrast to prior art devices, the vehicle door unlocking apparatus of the present invention is small and easy to store. It can be carried in a shirt pocket, so that it is out of the way when not in use. Instead of requiring the operator to work in the dark as is the case of the "slim jim", the door unlocking device of the present invention is observable by the operator during usage. It is thus easier to use and does not require a great deal of skill.
The guide sleeve and insertion tip are rigid and shaped to be positionable between a window and resilient seal or between a door window frame and resilient seal in an expeditious manner. The guide sleeve will not damage the vehicle, either by tearing or ripping the resilient seal or by scratching the paint. During insertion of the guide sleeve, the insertion tip protects the flexible wire loop and prevents it from being bent or displaced. Once the guide sleeve is in place, the flexible wires are easily extended out away from the insertion tip by manipulation of the free, exterior ends of the wires. The loop can be enlarged, placed over the door lock actuating rod, and then tightened about the rod, all in an easy manner and all in clear view of the operator.
The vehicle door unlocking device in accordance with the present invention is much easier to use, carry, and store than prior art devices. It is simple to operate, durable, yet inexpensive to make and works well with various types of door locks, either manual or power. It does not damage the vehicle during use and can be used and positioned in whatever orientation the situation requires. It is superior to the previously known devices and performs its intended function in an expeditious manner.
BRIEF DESCRIPTION OF THE DRAWINGS
While the novel features of the vehicle door unlocking device in accordance with the present invention are set forth with particularity in the appended claims, a full and complete understanding of the invention may be had by referring to the detailed description of the preferred embodiment, as is set forth hereinafter, and as is illustrated in the accompanying drawings in which:
FIG. 1 is a perspective view of the vehicle door unlocking device in accordance with the present invention with the lengths of the flexible wires being shortened for purposes of illustration;
FIG. 2 is a partial view, partly in section, of a portion of the vehicle door unlocking device;
FIG. 3 is a perspective view of a portion of the vehicle door unlocking device depicting placement of the device and formation of the flexible wire loop; and
FIG. 4 is a perspective view generally similar to FIG. 3 and showing the loop positioned about the vehicle door lock actuating knob.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring initially to FIG. 1, there may be seen a preferred embodiment of a vehicle door unlocking device, generally at 10, in accordance with the present invention. Vehicle door unlocking device 10 is comprised generally of a rigid, arcuate guide sleeve, generally at 12, a loop forming interior flexible wire portion 14, and an exterior flexible wire manipulation portion 16. As will be discussed in greater detail shortly, the interior loop forming wire portion 14 and the exterior manipulation wire portion 16 both include two individual wires 18 and 20 which extend through the arcuate guide sleeve assembly 12. However, for ease of discussion and comprehension they will be discussed as interior wire portions 14 and exterior wire portions 16. The terms "interior" and "exterior" denote the location of the wire portions as being interior or exterior of the vehicle during usuage of the vehicle door unlocking device of the present invention.
Again referring to FIG. 1 and also to FIG. 2, rigid arcuate guide sleeve assembly 12 is comprised of a pair of hollow, spaced, rigid guide tubes 22 and 24. Each of these guide tubes is formed generally in a semi-circle and each is positioned at a first end 26, 28, respectively, in spaced bores 30, 32, respectively, formed in a mounting block 34. A rigid support or guide rod 36 is positioned between the guide tubes 22 and 24 and has a corresponding arcuate shape. The two guide tubes 22 and 24 and the guide rod 36 are joined together by suitable means such as soldering or the like to form a strong, rigid guide member 40. Rigid guide rod 36 has a first end 42 that is received in a central bore 44 in mounting block 34 where it is held by a set screw 46. If necessary, the hollow guide tubes 22 and 24 and solid guide rod 36 can be separated from mounting block 34 by loosening set screw 46 and sliding the hollow guide tubes 22 and 24 out of bores 30 and 32 and rigid guide rod 36 out of bore 44. A generally oval insertion tip 50 is attached to second ends of hollow guide tubes 22 and 24 and intermediate rigid guide rod 36. Insertion tip 50 is open at its free end 52 and forms a housing for the loop forming interior wire portion 14 during insertion of the guide member 40 into the interior of the vehicle whose door is to be unlocked.
It is important that the arcuate guide sleeve 12 be sufficiently strong to withstand the forces exerted on it during insertion between a vehicle window and resilient seal or door frame. At the same time, the guide sleeve 12 must be small and thin enough that it does not damage the vehicle during insertion. In the vehicle door unlocking device in accordance with the present invention, this is accomplished by making the two guide tubes 22 and 24 from stainless steel tubing having an outer diameter of generally about 1/16 inch with a wall thickness of 0.010 inches. Each of the guide tubes is about 6 inches long. The solid guide rod 36 has the same overall dimensions but is solid. A guide tube size substantially greater than 1/16 inch would make the assembly difficult to insert in many vehicles.
Turning now to FIG. 2, it may be seen that each of the flexible wires 18 and 20 passes through one of the hollow rigid guide tubes 22 and 24. These flexible wires are sized to pass freely through the hollow guide tubes 22 and 24. Furthermore, the wires 18 and 20 are sheathed in a friction reducing flexible plastic such as nylon or the like to render them less apt to snag or catch within the hollow guide tubes 22 and 24. The free end of each one of the exterior portions of flexible wires 18 and 20 is provided with a manipulating handle 60, 62. These manipulating handles 60, 62 are, in the preferred embodiment, larger diameter rigid plastic sleeves which are bonded to flexible wires 18 and 20. It should be noted that the actual lengths of wires 18 and 20 are greater than that shown in FIGS. 1 and 2 with the actual lengths of the wires 18 and 20 being sufficient to span the length of a typical vehicle door.
Referring again now to FIG. 1, a loop 66 is formed at the free end of the interior loop forming wire portion 14. This is accomplished by forming a small eye 68 in the first flexible wire 18 such as by passing the end of wire 18 down through a metal sleeve or ferrule 70 and back up into the ferrule thereby forming eye 68. The free end of the second flexible wire 20 is passed through eye 68 and is inserted down into the top of ferrule 70 adjacent wire 18. The ferrule 70 is then pressed closed to form loop 66 whose size can be adjusted by relative movement of wire 20 with respect to flexible wire 18. As may be seen in FIG. 1, the encircling plastic or nylon has been removed from the loop forming ends of flexible wires 18 and 20 leaving the underlying wires 72 and 74 exposed. This increases the flexibility of the loop 66 and makes it easier to open and close.
Referring now to FIGS. 3 and 4, there may be seen an operational sequence utilizing the vehicle door unlocking device 10 of the present invention to unlock a locked vehicle door 80. This door 80 is shown in a somewhat schematic manner and includes a conventional window 82 which, as shown in FIGS. 3 and 4, is slideable vertically in a rigid window frame 84. This is a structure typical of sedans and similar vehicles in which the window frame 84 moves with the door 80 during opening and closing, and in which an opening 86 between the window frame 84 and the vehicle roof support pillar 88 is sealed with a resilient sealing gasket (not shown). In an alternate configuration (not shown), the window 82 is frameless and seals directly against a sealing gasket carried by the vehicle roof support pillar 88 or by the rear window. In either situation, the vehicle door unlocking device 10 is positioned adjacent the exterior of the vehicle door and window with the flexible wires 18 and 20 retracted so that small loop 66 and eye 68 are shielded within the open end 52 of insertion tip 50. The insertion tip is then inserted between either the door frame 84 and resilient sealing gasket through opening 86 or between the window glass 82 and the resilient sealing gasket, depending on the style and configuration of the vehicle. Once the insertion tip 50 and guide member 40 have been inserted into the vehicle's interior, the small loop 66 and eye 68 can be extended out from the open free end 52 of insertion tip 50 by exerting a slight forward force on manipulating handles 60 and 62. The eye of loop 66 is then increased by continued forward movement of wire 20 through use of handle 62, while holding handle 60 stationary. As soon as the loop 66 has been sufficiently enlarged, it can be positioned about a door lock actuating rod or knob 90 positioned on the interior of vehicle door 80 in a generally known manner. The loop 66 is then made smaller by retraction of wire 20 until the loop is snug about knob 90. Continued retraction of flexible wires 18 and 20 will elevate knob 90 to unlock the door 80. In some situations, it is also beneficial to raise the guide member 40 to facilitate raising knob 90. Since loop 66 has been tightly secured about knob 90, there is little likelihood of the loop sliding up off knob 90 even if the knob does not have an enlarged head. The tight engagement of loop 66 about knob 90 is particularly beneficial when the vehicle is equipped with electric door locks since these require greater force to operate than do conventional, non-electric door locks. Once door 80 has been unlocked, it can be opened and the door unlocking device 10 can be removed by again enlarging loop 66 and removing it from knob 90. Loop 66 can then be reduced in size, placed within insertion tip 50 and the unlocking device 10 can be stored in a small amount of space.
As has been discussed above, the vehicle door unlocking device 10 of the present invention is small and easily stored yet is more effective than larger prior art devices. It is easy to operate and does not require a great deal of operator skill since it is always within the user's sight. It can be used with various styles and configurations of vehicles without harming or damaging window glass, window frames, door frames, paint and the like. It firmly grasps vehicle door lock actuating rods or knobs, even those without enlarged heads, and is able to also unlock many electric locks.
While a preferred embodiment of a vehicle door unlocking device in accordance with the present invention has been fully and completely set forth hereinabove, it will be obvious to one of skill in the art that a number of changes in, for example, the length of the flexible wires, the shape of the mounting block, the specific curvature of the guide tubes and guide rod, and the like could be made without departing from the true spirit and scope of the present invention which is accordingly to be limited only by the following claims. | A vehicle door unlocking device utilizes a pair of spaced, rigid hollow guide tubes to form a guide member that is insertable into the interior of a vehicle through an opening in the vehicle formed by the door or window and a resilient seal. A pair of flexible wires are slideably carried in the guide tubes and have manipulating handles on ends thereof which remain on the exterior of the vehicle. The ends of the wires positionable interiorly of the vehicle are manipulatable from outside the vehicle to form an enlarged loop that is positioned about a poor unlocking rod. Once the loop has been properly positioned, its size is reduced and the door lock rod can then be raised to unlock the vehicle door. | 4 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device for locating a port, facing the exterior of a patient, on a medical implant.
2. Description of the Prior Art
Some medical implants, such as implantable systems for the infusion of liquid medication as shown in FIG. 1, contain ports, viz. a medication filling port 2 and sometimes a so-called flushing port 4, located on the catheter connection 6, for checking and measuring the functioning of the catheter 8 (i.e. whether it is open or occluded etc.), flushing and cleaning the catheter, internal washing and cleaning of the medication container, pump, flushing port etc., for checking pump functions such as stroke volume, backflow etc. and for injecting contrast medium into the catheter for various studies.
The ports are covered by a septum in the form of a rubber membrane. After the device has been implanted in the abdominal wall, the skin and septum can be punctured by a cannula to gain access to the port to refill medication or conduct one of the aforementioned procedures.
Locating the relatively small port, the diameter of which is typically 5 mm, with the tip of the cannula is very difficult. This is especially the case in obese patients in whom finding even the catheter connection molding by palpation may be difficult. The cannula tip is damaged every time the cannula is incorrectly inserted and must be replaced, since a bent cannula tip would damage the septum rubber. This procedure with repeated punctures can be very taxing for both patient and physician, which makes the above-mentioned procedures difficult.
Attempts have been made to facilitate the described procedure by noting the position of the catheter connection on a drawing as a guide in subsequent palpation.
U.S. Pat. No. 4,573,994 discloses a medication infusion apparatus with a funnel-shaped port entrance to facilitate guidance of the cannula tip toward the septum-covered port opening. This patent also shows different ways to confirm that the cannula has reached the correct position in the port.
SUMMARY OF THE INVENTION
An object of the present invention is to solve the aforementioned problems associated with conventional devices and to provide a device for reliably locating the port of a medical implant from the exterior of the patient's body.
The above object is achieved in accordance with the principles of the present invention in a device for locating a port of an implanted medical device which employs two magnetically interacting elements, a first of these magnetically interacting elements being associated with the port at the implanted medical device, such as by surrounding the port, and a second of these magnetically interacting elements being adapted to be moved over the exterior surface of the patient in whom the medical device is implanted. One of the magnetically interacting elements can be a source of a magnetic field and the other of the magnetically interacting elements is then a magnetic field detector. The magnetic field source may be implanted as a part of the medical implant, associated with the port, and then the detector will be the element which is movable over the exterior of the patient. Alternatively, the detector can be implanted with the medical implant and the magnetic field source can be moved over the exterior of the patient. In this alternative, the magnetic field detector will include, or will be connected to, means for providing some type of indicator signal to the exterior of the patient. In another alternative, one magnetically interacting element can be a ferromagnetic element and the other magnetically interacting element will then be an element having an inductance which is alterable dependent on the position of the ferromagnetic element.
In all of these alternative embodiments, the first and second magnetically interacting elements magnetically interact with each other as the second magnetically interacting element is moved over the exterior of the patient, and the magnetic field detector, whether implanted or on the exterior of the patient, provides an extracorporeally perceptible indication when the first and second magnetically interacting units are in a defined spatial relationship, such as the second magnetically interacting element being disposed over the implanted first magnetically interacting unit. The location of the port in the patient is thus identifiable from this extracorporeally perceptible indication. The term "magnetically interact" is used herein in a broad sense, which encompasses inductive interaction.
In the device according to the invention, the relative position of a magnet and a magnetic field detector is thus determined, one of these components being implanted and located at a given position in relation to the port of the implant, whereas the other component is movable on the exterior of the patient's body, and the port of the medical implant is located from the determined relative positions of these components. Alternatively, a coil is implanted in a given position in relation to the port of the implant, and a means, made of a ferromagnetic material, is moved on the exterior of the patient's body over the area of the coil, and from ensuing changes in the inductance of the coil, the relative positions of the coil and the ferromagnetic means, and accordingly the position of the port, can be determined by moving the ferromagnetic means on the exterior of the patient's body.
In one embodiment of the device of the invention, the port is equipped with a rod-shaped magnet, more precisely arranged behind the port along the extension of the central axis of the port. "Centering" the magnet in this way in relation to the port results in greater aiming accuracy when localizing the port.
According to other embodiments of the device of the invention, the detector has a fixture plate, intended to be moved on the patient's skin to locate the port, and an indicator, actuated by the magnetic field and movingly arranged in the fixture plate, designates the position of the port by its position in relation to the fixture plate. The movable plate of the detector has an axially magnetized spherical body which is journaled with low friction in a spherical recess in the plate. When the fixture plate is opposite the port the magnetic body rotates to a given position in the recess. The spherical body is preferably arranged inside a spherical shell with a larger radius than that of the spherical body, the space between the shell and the body being filled at least in part with a liquid to achieve a "suspension" with a minimum of friction. Since the space between the shell and the body is filled with a liquid the density of which is essentially the same as or somewhat higher than that of the spherical body, the spherical body will float in the liquid. The interior of the shell, or the exterior of the spherical body, are also advantageously provided with bumps preventing extended direct surface contact between the spherical body and the shell, thereby avoiding increased friction as a consequence of such a surface contact.
According to another embodiment of the inventive device, a hole is made in the middle of the recess through the fixture plate and a cannula guide is devised to fit in the recess, after the fixture plate has been positioned over the port and the spherical body or the shell has been removed from the recess, the cannula guide being devised to steer a cannula inserted into the guide through the hole in the fixture plate into the port.
According to another embodiment of the device of the invention, at least three indicators, which can be actuated by the magnetic field are movably arranged in the fixture plate, the position of the indicators in relation to the fixture plate designating the position of the port, and the fixture plate further has a cannula guide for guiding a cannula, inserted into the guide, into the port when the fixture plate is in the correct position. This makes it possible to verify continuously that the fixture plate is in the correct position during insertion of the cannula into the port.
In another embodiment of the invention, the cannula has a small diameter along an end section of a given length at the tip and a larger diameter along the rest of the length of the cannula. The end section of the cannula must have a small diameter, so the puncture hole in the port's septum becomes small enough to allow the septum to seal when the cannula is withdrawn. In order to avoid such fine diameter cannulas from being too weak (i.e., too susceptible to bending) they can only be made of limited lengths. This means the cannula will be too short for use with many patients and this problem is accentuated when a fixture plate with a cannula guide is used. Devising only the end section with a small diameter and the rest of cannula with a larger diameter, however, will make cannulas for the most widely ranging abdominal thicknesses stiff enough. Further, the shoulder formed at the location where diameter changes can serve as a stop which prevents the cannula from being inserted too deeply. In this way the risk is eliminated that the cannula tip might hit the bottom of the port and be bent or damaged in some other way, such that the septum is damaged when the cannula is withdrawn.
According to other embodiments of the device of the invention, a coil is wound around the port and is energized by a power source in the implant, the power source being telemetrically controllable from outside the patient. In this way the coil can be conveniently energized only on occasions when a port is to be located, thereby reducing power consumption.
In another embodiment, the unit for determining the change in coil inductance, when a ferromagnetic means on the exterior of the patient's body is moved across the coil area is arranged in the implant, and telemetry equipment is arranged to transmit the determined inductance change to an external received indicator. Thus, the port in question can be located from the outside of the patient's body. The ferromagnetic means can advantageously consist of the cannula, intended to be inserted into the port. The sensed change in induction occurring when the cannula is introduced is then transmitted to the external received indicator, so the insertion of the cannula into the port can be guided with the aid of the received indicator.
DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a front view of a conventional medical implant in the form of a system for the infusion of liquid medication.
FIG. 2a shows a part of the infusion device in FIG. 1 with a tubular permanent magnet embedded around the flushing port of the device, and FlG. 2b shows an axially magnetized tube for locating the port when the infusion device is implanted, in accordance with the principles of the present invention.
FIGS. 3a and 3b show a fixture plate at the device according to the invention respectively in a top view and in cross section.
FIG. 4 shows a cross section of a cannula guide for use in the fixture plate in FIG.2.
FIG. 5a shows a spherical body, fitted into the recess of the fixture plate of FIGS. 3a and 3b and with a rod-shaped permanent magnet arranged inside the body.
FIG. 5b shows a solid permanent magnet spherical body for use in the invention.
FIG. 6 illustrates the use of the inventive fixture plate with the spherical body for locating the flushing port of an implanted infusion device, a rod-shaped permanent magnet being arranged behind the port along the extension of the center axis port.
FIG. 7 shows the introduction of the cannula into the flushing port with the aid of the cannula guide in the inventive fixture plate.
FIG. 8 shows an embodiment of a cannula, suitable for introduction into a port of the implant with the aid of a fixture plate in accordance with the invention.
FIG. 9 top view of an alternative embodiment of the fixture plate of the invention.
FIG. 10 illustrates different versions of an embodiment of the invention with a coil arranged around the flushing port of an infusion device.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A device for the infusion of liquid medication, as depicted in FIG. 1, has been described above.
FIG. 2a shows in larger scale a part of the infusion device in FIG. 1 with the catheter connection 6 and the flushing port 4, around which a permanent magnet in the form of a tube 10 is embedded in accordance with the invention. The tubular magnet 10 is axially magnetized, (see FIG. 2b), and has high coercive force and a high energy product. A large magnetic moment is desirable for obtaining the best axial field distribution.
Recesses are provided in the magnet for input and output tubes 12 and 14 to and from the flushing port 4, (see FIG. 6).
As an alternative, a rod-shaped permanent magnet can be 5 arranged coaxially with the port 4 and behind the same along an extension of the center axis of the port 4, (see FIG. 6).
The port 4 itself, as well as the enclosure of the device and other adjacent materials, should be non-magnetic, e.g. made 10 of titanium or epoxy plastic.
FIGS. 3a and 3b show a fixture plate 16 with a central, hemispherical recess 18 with a small hole 20 in the middle.
FIG. 5a shows a spherical device, fitted into the recess 18 in the fixture plate 16. For localizing the flushing port 4, equipped with a magnet, the spherical device is placed in the recess 18 with an equatorial plate 22, arranged on the device, bearing against the upper side of the fixture plate 16.
The spherical device has an external shell 24, at least the upper half of which is transparent and has a central marking 26, in the form of a cross or the like, on its top.
A spherical body 28 is mounted inside the outer shell 24 with the lowest possible friction. This is appropriately achieved by completely or partly filling the space 30 between the outer shell 24 and the spherical body 28 with a liquid. The center of gravity of the spherical body 28 should be located as centrally as possible to prevent undesirable torques. The resulting density of the spherical body 28 is preferably equal to or almost equal to the density of the liquid in the space 30. The spherical body 28 will then float in the liquid with extremely low friction, and the absence of air and/or a liquid meniscus will eliminate undesirable surface tension forces.
Alternatively, the spherical body 28 can be devised in such a way that its resulting density is less than the density of the liquid. The space 30 is then filled to such a degree that 5 the spherical body 28 floats centrally in the outer shell 24.
In both the above described embodiments, a number of "bumps" 32, i.e., at least four, can be arranged on the inner side of the outer shell 24, or on the outer side of the spherical body 28, to avoid extended surface contact and, accordingly, increased friction, between the spherical body 28 and the shell 24.
The spherical body 28 can be made of a non-magnetic material 15 with a permanently magnetized bar magnet 34 arranged along a diameter (see FIG. 5a). The surface of the spherical body 28 is provided with a visible marking 36 at its north pole.
As an alternative to the above described version, the 20 spherical body can be a solid, axially magnetized permanent magnet 28a, as shown in FIG. 5b.
As an alternative to the above described "frictionless" suspensions of the spherical body 28, other known principles for suspending principles for suspending a bar magnet with a central pivoting point, coinciding with the center of gravity of the magnet and with two angular degrees of freedom inside the outer shell, can be used, since rotation around the axis of the bar magnet is unnecessary. As an example some form of gyro suspension of the bar magnet can be used, the spherical body itself then not being needed. The spherical outer shell, however, can be filled with liquid for damping and/or lubricating the mechanical system, if desired.
Locating the port with the device according to the invention is performed as follows:
The patient with the implant in his or her abdomen is placed on his or her back, and the fixture plate 16 is positioned with its center in the vicinity of the anticipated location of the port. The plate 16 has a comparatively large diameter for stable placement on the skin of the patient's abdomen. The spherical sensor device is inserted into the recess 18 in the plate 16 with the equatorial plate 22 bearing against the upper side of the fixture plate, as shown in FIG. 6. The fixture plate is moved laterally on the abdomen, the magnet 34 being acted on by the magnetic field from the magnet 38 at the port 4, and as the mark 36 at the north pole of the magnet 34 becomes aligned with the marking 26 on the outer shell 24, the fixture plate 16 becomes situated opposite the port 4, and it is immobilized in this position. The spherical sensor device is then lifted out of the recess 18 and is replaced with the cannula guide 40 shown in FIG. 4. The cannula guide 40 fits in the recess 18 with the channel 42 aligned with the hole 20 in the fixture plate 16. A cannula 44 can then be passed through the channel 42 and hole 20 into the port 4, the fixture plate 16 with the cannula guide 40 then serving as an aiming means, as shown in FIG. 7.
In the embodiment shown in FIG. 7, the port 4 is encircled by the tubular magnet 10, and the port 4 itself is covered by a rubber septum 46 which is penetrated by the cannula 44. The cannula 44 is further connected to a syringe 48 containing the liquid 50 injected into the port after the cannula 44 has been introduced.
As an alternative to the use of the cannula guide 40, a marking can simply be made on the patient's skin with a suitable pen through the hole 20 in the base of the fixture plate 16 after the sensor device has been removed. The 35 fixture plate 16 is then removed, and the cannula 44 can be inserted perpendicularly to the skin at the marking.
The earth's magnetic field is negligible, compared to the near field of the permanent magnet. It is desirable, however, that strong sources of interference, such as electromagnets, other permanent magnets, soft iron etc., be avoided in the vicinity of the sensor device in order to reduce undesirable deviations.
The cannula 44 which is used must have a small diameter to prevent damage to the septum 46. The cannula 44 will therefore be weak and can only be made in limited lengths. Currently employed cannulas are therefore rather short for many patients and the problems with short cannulas are accentuated when using a fixture plate 16 with cannula guide 40. It is therefore advantageous to devise the cannula in the way shown in FIG. 8. The end section 52 of this cannula has a small diameter to only make a tiny puncture hole in the septum. The length of this end section 52 is limited, typically 7 to 8 mm. The remainder 54 of the cannula has a larger diameter, enabling the cannula to be made long enough to suit most varying abdominal thicknesses while maintaining sufficient stiffness. Another advantage with this design of the cannula is that a shoulder, blocking further penetration of the septum by the cannula, is formed at the diameter change junction 56 of the cannula. In this way it can be avoided that the tip of the cannula strikes the bottom of the port 4, which is an important advantage since the cannula tip would be bent if it is pressed against the bottom of the port 4. A bent cannula tip would then damage the septum rubber when the cannula is withdrawn from the port 4.
FIG. 9 shows an alternative embodiment of a fixture plate 58 with three sensor devices 60 of the above described kind. The sensor devices 60 are symmetrically arranged around the 35 center of the fixture plate 58 where a channel 62 is formed perpendicularly through the plate 58.
With the aid of the sensor devices 60, the plate 58 can be positioned exactly over the port, equipped with a magnet, so the channel 62 is right over the port in a manner analogous to that described above, whereupon a cannula can be introduced through the channel 62 and into the underlying port, the channel 62 thus serving as an aiming means.
In this embodiment, the sensor devices 60 do not have to be removed from the fixture plate 58 when the cannula is introduced through the guide channel 62. The sensor devices 60 can therefore be permanently mounted in the fixture plate 58, and checks can be made, throughout the process of introducing the cannula into the port and injecting liquid, to ensure that the fixture plate 58 is in the correct position in relation to the port.
FIG. 10 shows another alternative embodiment of the device according to the invention in which the flushing port 64 is made of a non-ferromagnetic metal and is encircled by a coil 66. The winding of the coil is connected, via a hermetically sealed two-pin terminal block 68, to transceiver electronics 70 in the hermetically sealed electronics compartment of the infusion device. The transceiver electronics 70 can be activated by a 25 telemetry unit 72 placed on the patient's abdomen above the implant to deliver a weak alternating current at an appropriate frequency through the coil 66.
The cannula 73 which is to be introduced into the flushing 30 port 64 via the port's septum 76 is inserted through the skin at an appropriate point 74.
Conventionally, the appropriate point 74 can be located by palpation of the molding for the connection 78 for the catheter 80. This palpation 35 may be difficult on obese patients. Alternately, the surgeon can make a mark, e.g. a small tatoo or the like, on the patient's skin immediately above the port at the time of implantation of the infusion device.
A better and more accurate technique according to the present invention is achieved by placing a ferromagnetic test body 82 on the patient's skin. This body 82 affects the inductance of the coil 66, and this effect is a function of the distance to and angle in relation to the coil axis. The maximum effect on the coil inductance is achieved when the test body 82 is situated immediately above the flushing port, provided the axis of the coil is reasonably perpendicular to the plane of the abdomen.
An alternative according to the invention for locating the correct position for inserting the cannula into the patient is to sense the alternating field from the coil 66 of the flushing port 64 with the aid of a detector coil 84 and attendant detector electronics 86. A maximum signal is obtained from the detector coil 84 when it is in a position on the abdomen which is coaxial to the coil 66 of the flushing port 64.
Another alternative according to the invention is to use a cannula 73 made of a ferromagnetic material. When the cannula 73 then is inserted into the abdominal wall at the point 74 and approaches the flushing port 64, the inductance of the coil an increases, an increase detectable with the electronics unit 70.
The change in inductance can be detected e.g. as a change in current, a change in phase angle or a change in the resonance frequency of a tuned LC circuit. The change in the actual parameter is transmitted by telemetry to the transceiver electronics 88 in the telemetry unit 72 and is presented with appropriate indication unit 90, such as an acoustic signal generator, optical signal generator or the like. Thus, the indicating unit 90 can be arranged to emit e.g. an acoustic signal whose strength, or frequency, is proportional to the inductance of the coil 66. As the tip of the cannula comes closer to the flushing port 64, the signal becomes stronger or, alternatively, the frequency of the sound becomes higher. Alternatively, the indication unit 90 can be a lamp, light-emitting diode or the like which blinks at a varying rate depending on the proximity of the cannula 73 to the port 84.
By utilizing feedback obtained via the indication unit 90, the operator can slowly advance the cannula 73 toward the port 64 and steer it accurately until the cannula 73 hits the flushing port 64.
When the cannula 73 has reached the correct position in the 15 flushing port 64, the electronics 70 are deactivated by a telemetry signal from the unit 72 in order to save energy in the battery of the implant.
In the above described manner, the presence of the cannula 73 in the port 64 can thus be sensed inductively. Thus, the correct position of the cannula 73 can be verified throughout the entire flushing operation. Verifying that the cannula is in the correct position in the port in question is particularly important when implanted infusion devices are filled with medication, such as insulin. According to the above, a similar device can be consequently be employed to ensure that the cannula remains in the filling port 2 in FIG. 1 throughout the filling operation, so insulin is not injected at an erroneous site because the cannula slips out of the filling port.
The above described technique according to the invention can also be applied to standard cannulas made of non-ferromagnetic materials. Eddy currents and losses in non-ferromagnetic metals cause a detectable reduction in inductance, a phase shift in the current etc. The effect is less pronounced, however, than when a cannula made of a ferromagnetic material is used. Moreover, the coil-encircled port in this instance is made of metal which reduces sensitivity to the position of the cannula. This difficulty will be eliminated if the metallic material, such as polymer, ceramic or the like.
All the components in the device according to the invention are advantageously made of materials and are devised in a way 10 enabling them to be sterilized with normal methods.
Although modifications and changes may be suggested by those skilled in the art, it is the intention of the inventor to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of his contribution to the art. | A device for locating a port, facing the exterior of a patient, on a medical implant has at least one magnet and a detector arranged to sense magnetic fields. The magnet is associated with the implanted port and the detector is arranged to sense the magnetic field from the outside of the patient's body and, on the basis thereof, determine the location of the port. Alternatively, the detector is associated with the (implanted) port and the magnet is intended to be moved across the area above the detector on the exterior of the patient's body to then determine the location of the port from the magnetic field detected. The device can alternatively use a coil which is associated with the (implanted) port and a ferromagnetic element is moved on the exterior of the patient's body over the area above the coil. Changes in the inductance of the coil when the ferromagnetic means is moved are monitored and, therefrom, the position of the port is identified. | 0 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of U.S. Pat. No. 6,539,727 (U.S. Ser. No. 10/026,167) filed Dec. 21, 2001 to Burnett, issued Apr. 1, 2003, entitled “Angled UV Fixture”.
STATEMENT OF FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
BACKGROUND OF THE INVENTION
1. Technical Field
This invention relates in general to air conditioning systems and, more particularly, to ultraviolet light fixtures.
2. Description of the Related Art
Over the last several years, the use of ultraviolet (UV) light in commercial and residential air conditioning applications has become more popular. A UV light source in the UV-C spectrum, specifically at 253.7 nm, and potentially UV light in other frequencies such as 187 nm, has been shown to be extremely effective in destroying bacteria and fungi in air conditioning systems.
During operation of an air-conditioning system, water condenses on the heat exchanger (typically referred to as the condensing coil). The drain pan is situated below the coil and collects run-off from the coil. Because the cool and moist environmental conditions in the coil are conducive to microbial infestations, UV lamps are often used to illuminate the coil and drain pan. U.S. Pat. No. 5,817,276 to Fencl et al claims that the UV lamp should be oriented perpendicular to the fins of the coil for maximum reflection within the coil.
Mounting a substantially straight lamp perpendicular to the fins, however, has some significant shortcomings. First, in some orientations, the fins will be horizontal in relation to the drain pan. If a substantially linear UV lamp is mounted perpendicular to the drain pan, its effectiveness in killing bacteria in the drain pan may be reduced. Further, mounting a linear UV lamp perpendicular to the fins may result in the use of a relatively short UV lamp, which will not emit as much UV energy as would a longer lamp.
In U.S. Ser. No. 10/026,167, filed Dec. 21, 2001, entitled “Angled UV Fixture” to Burnett, which is incorporated by reference herein, an angled UV lamp fixture is shown. The angled orientation overcomes many of the shortcomings of the prior art.
It is also important that a UV lamp be mounted inexpensively and securely, with precautions taken to reduce the risk of inadvertent UV exposure.
Therefore, a need has arisen for a method and apparatus for UV filtration that maximizes energy to the coil and drain pan for higher microbial efficacy.
BRIEF SUMMARY OF THE INVENTION
In a first aspect of the invention, a mounting system for mounting a germicidal lamp to a sidewall at an angle comprises first and second slide clips. The first slide clip has a planar surface having an opening for engaging the germicidal lamp and an extended portion formed at an angle to said first planar surface, such that the planar surface is held at an desired angle relative to the sidewall when the first slide clip is positioned against the sidewall with the extended portion in contact with the sidewall. The second slide clip has a planar surface with an opening for engaging the germicidal lamp and is slideably engaged with said first slide clip.
In a second aspect of the invention, a germicidal lamp is mounted in a duct. An access cover is coupled to the duct for covering said germicidal lamp, where the access cover has a hole formed therein for receiving an electrical connection to the contacts.
In a third aspect of the invention, an integral piece of material has openings formed therein for receiving a plurality of germicidal lamps. The integral piece of material is secured to a sidewall to mount the germicidal lamps.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS 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 a illustrates a perspective view of a coil illuminated by a angled germicidal lamp; FIGS. 1 b and 1 c illustrates top and side cross-sectional views of FIG. 1 a ;
FIG. 2 illustrates a first embodiment of an angled mounting system;
FIG. 3 illustrates an exploded view of a retainer mechanism;
FIGS. 4 a and 4 b illustrate side and front views of the retainer mechanism of FIG. 3 a in a locked position;
FIGS. 5 a and 5 b illustrate top and side views of an alternative embodiment of an angled mounting system;
FIGS. 6 a and 6 b illustrate top and side views of a security access cover for preventing access to a UV lamp without prior disconnection of the ballast power supply;
FIG. 6 c illustrates a top view of a flanged plug for use with the security access cover of FIGS. 6 a and 6 b ; and
FIGS. 7 a and 7 b illustrate side and front view of a multiple lamp mounting clip.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is best understood in relation to FIGS. 1-7 of the drawings, like numerals being used for like elements of the various drawings.
FIG. 1 a illustrates a generalized perspective view of the present invention. A coil 10 , having fins 12 and coolant exchange tubes 14 , is disposed in a duct 15 of an air conditioning system. A drain pan 16 is disposed below the coil, such that condensation from the coil 10 flows into the drain pan 16 . A germicidal lamp 18 is disposed between a first position near an upper corner 20 of the coil 10 and a second position near opposite lower corner 22 . Airflow is shown as passing through a filter 24 , which typically precedes the coil 10 in the direction of the airflow. Generally, the airflow is produced by a blower motor (not shown). The blower motor is often placed between the coil 10 and filter 22 , although it could also be placed before the filter or after the coil. The relative order of the blower motor, filter 24 and coil 22 is not critical for the operation of the present invention. Also, while the duct of FIG. 1 a is shown in a horizontal configuration, it could be vertical or at any angle in other configurations. Further, the any type of germicidal lamp 18 could be disposed on either side of the coil, or on both sides. The lamp 18 could be, for example, a single-ended, dual-ended, bi-pin, or mini bi-pin or other configuration. In a dual-ended configuration, an electrical connection to the far side could be made, for example, using a uni-strut angle bracket with the terminal box and electrical connections.
In operation, the air in duct 15 is forced through the coil 10 by a blower motor. The fins 12 are cooled by the coolant exchange tubes 14 ; hence air passing over the fins is cooled as well. Cooling the air causes condensation to form on the tubes 14 and fins 12 . Gravity causes the condensation to flow towards the drain pan 16 . The cool moist conditions are ideal for the growth and reproduction of bacteria, mold and other microorganisms on the coil 10 and in the drain pan 16 .
The germicidal lamp 18 shines on both the coil 10 and the drain pan 16 Typically, the germicidal lamp is a UVC frequency lamp, which has been shown to be extremely effective in combating bacteria and mold and other airborne organisms. Other frequencies could also be used.
Placing the germicidal lamp 18 at an angle of 10 degrees to 80 degrees to a duct sidewall 17 , preferably from a position near one corner of the coil 10 towards an opposite comer of the coil 10 (rather than orienting the lamp horizontally or vertically with respect to a sidewall 17 of duct 15 ) provides significant benefits. First, the angled disposition of the lamp 18 allows a longer lamp to be used. A longer lamp provides a greater energy output than a shorter lamp of the same intensity. Hence, more energy is available for destroying microorganisms. The increased energy is particularly evident in the drain pan 16 .
FIGS. 1 b and 1 c illustrate top and side views, respectively, of the air conditioning system of FIG. 1 a . In FIG. 1 b , an angled mount 26 is shown which allows the germicidal tube 18 to be mounted on a sidewall 17 of duct 15 at a desired angle. Embodiments for the angled mount 26 are shown in greater detail in connection with FIGS. 2-5 .
FIG. 2 illustrates a partially cross-sectional view of a first embodiment of an angled germicidal lamp that allows for variable angle positioning. FIG. 2 illustrates a side view of a germicidal lamp 18 disposed through a hole 19 in duct 15 (shown in cross-section) at an angle set by angled mount 26 . Germicidal lamp 18 is preferably a single-terminated lamp or doubleterminated lamp with return wires such that all electrical connections are available at one end of the lamp. Lamp 18 includes an endcap 28 at the end of the lamp 18 within the duct 15 and an endcap 30 at the end of the lamp 18 outside of the duct 15 . Endcap 30 includes a flange 32 which is oriented in a plane perpendicular to the longitudinal axis of the lamp 18 , or at another fixed angle. Electrical contacts 31 protrude endcap 30 ; these contacts are connected to the ballast.
Angled mount 26 includes angled coupler 34 (shown in cross-section) and restraining mechanism 36 . Angled coupler 34 abuts a sidewall 17 of duct 15 and flange 32 , thus holding the longitudinal axis of lamp 18 at a desired angle to the plane of the sidewall 17 of duct 15 and, consequently, to the coil 10 , as shown in FIG. 1 . Restraining mechanism 36 holds the flange 32 and angled coupler 34 fixedly against duct 15 .
In typical installations, the coil 10 is accessible from the outside through a “cabinet” or “housing”. For purposes of this specification, the cabinet or housing will be considered part of the duct 15 . Further, electronics for powering the germicidal lamp 18 , commonly referred to as a “ballast”, are contained in a housing which is typically secured to the outside of the duct 15 . It is possible, and sometimes most efficient, to attach the lamp 18 to the ballast housing; therefore, for purposes of the specification, the ballast housing or any other housing for containing the end of lamp 18 , is considered to be part of the pertinent sidewall 17 of duct 15 as well.
FIG. 3 illustrates an exploded view of a restraining mechanism 36 that could be used in connection with lamp 18 and angled coupler 34 to hold the lamp 18 at the desired angle. Restraining mechanism 36 includes a slide clip 38 with dual slots 40 . Threaded studs 42 , which are attached to duct 15 , are disposed through respective slots 40 , such that slide clip 38 can travel up and down in relation to the studs 42 when the restraining mechanism is in an “unlocked” state. Nuts 44 are threaded to screw onto studs 42 . On each stud 42 , a locking washer 46 and a spring 48 are disposed about stud 42 on the opposite side of slide clip 38 from nuts 44 .
FIGS. 4 a and 4 b illustrate side and front views of the restraining mechanism 36 of FIG. 3 in a “locked” position with the nuts 44 tightened to firmly press flange 32 and angled coupler 34 against duct 15 (shown in cross-section in FIG. 4 a ). The slide clip 38 is placed such that the narrow portion of the opening is set against the endcap 30 with the clip 38 pressing against flange 32 . In this position, springs 48 press lock nuts 46 against the opposite side of slide clip 38 so that the slide clip is restrained by friction from sliding upwards to an unlocked position.
FIG. 4 b illustrates a front view of the restraining mechanism in the locked position.
In operation, the angled germicidal lamp shown in FIGS. 1-4 can be used to accommodate a variety of coil configurations and sizes. To mount the germicidal lamp, the installer forms hole 19 in the duct 15 through which the lamp 18 will be installed. Typically, the hole would be located on the duct at a position near an upper corner of the coil 20 . The studs 48 are secured to the duct 15 at the sides of the hole 19 (in general, it is beneficial to secure the studs to a plate or chassis to reinforce thinner duct material). A spring 48 and locking washer 46 are placed around each stud 48 . Slide clip 38 is placed over the studs 48 and the nuts 44 are placed over the studs 48 . An angled coupler 34 is chosen such that the lamp 18 is directed to the opposite corner of the coil 20 , as shown in FIG. 1 . The selected angled coupler 34 is placed around the lamp 18 and positioned against flange 32 at the opposite end of the lamp 18 . The lamp 18 is placed through the hole 19 such that the angled coupler 34 is flush against duct 15 and flange 32 is flush against the angled coupler 34 . The slide clip is placed in a locked position against the flange and the nuts 44 are tightened.
In general, the lamp is oriented between two opposite corners, as shown in FIG. 1 . The germicidal lamp 18 , however, should be angled such that the end of the lamp does not protrude lower than the plane of the top of the drain pan 16 . Also, in order to enter at a flat portion of the duct 15 , the lamp may be positioned somewhat below the upper corner of the coil 10 . Typically, the angle of the longitudinal axis of the lamp will be between 10 and 80 degrees relative to the horizontal plane at the top of the coil 10 or at the edge of the drain pan 16 , depending upon the application and the relationship between coil depth, width, height and angle of tilt in the air-handling unit. The lamp 18 could enter the duct at a corner as well, although the mounting may be more difficult.
FIGS. 5 a and 5 b illustrate an alternative embodiment for angling lamp 18 . In this embodiment, an automatically angled restraint mechanism 50 including two slide clips 38 is used to angle the lamp 18 . A “bottom” slide clip 38 a (i.e., the slide clip 38 closest to the sidewall 17 ) is oriented such that an angled portion 52 and opposite tip 54 cause the planar portion 56 of the clip 38 to form a desired angle with the sidewall 17 . The planar portion 56 of “upper” slide clip 38 b rests against the planar portion 56 of slide clip 38 a . The slide clips 38 a and 38 b are oriented such that a hole is formed in their interiors to expose hole 19 in sidewall 17 .
Threaded studs 42 , which are attached to sidewall 17 , are disposed through overlapping slots 40 of both clips 38 a and 38 b , such that the slide clips 38 can travel up and down in relation to the studs 42 when the restraining mechanism is in an “unlocked” state. Nuts 44 are threaded to screw onto studs 42 . A locking washer 46 and a spring 48 are disposed about stud 42 between the bottom clip 38 a and the sidewall 17 .
The restraining mechanism 50 provides significant benefits to the installer. First, it is easily and inexpensively manufactured from sheet metal.
Second, it is easily installed at the site. Third, the angled portion 52 can be designed to support different angles, or it can be bent using standard tools at the installation site to provide the proper angle.
FIGS. 6 a and 6 b illustrate a front view and a cross-sectional side view, respectively, of a security access cover 60 for protecting technicians and home owners from possible electrical shock while servicing the UV lamp 18 . The security box 60 can be used with any UV lamp orientation, either straight or angled. For ease of illustration, the security access cover 60 is shown in FIG. 6 b with a straight lamp installation.
The security access cover 60 is attached to sidewall 17 of duct 15 using, for example, studs 62 and nuts 64 . The security access cover 60 completely covers the endcap 30 of the lamp 18 . An access hole 66 is disposed through the cover to allow access by a plug 68 , including female power socket 70 , power cable 72 , and shield 74 (shown in cutaway view in FIG. 6 b to expose the power socket 70 ). The power cable 72 is coupled to the UV ballast (not shown) and supplies power to the pins 31 of lamp 18 .
In operation, the security access cover is difficult to remove without first disconnecting the plug 68 from the UV lamp 18 . This greatly reduces the possibility of a technician or home owner from UV exposure and from accidental contact with the electrical output of the ballast and prevents anyone from removing the lamp without first disconnecting the lamp from the electricity from the ballast.
FIG. 6 c illustrates an embodiment of shield 74 where it is impossible to remove the security access cover 60 without first disconnecting the power. In this embodiment, a flange 76 (or other protrusion) is disposed about the top of shield 74 , such that the flange 76 is located on the top of security access cover 60 when connected to the UV lamp in normal operation. Any attempt to remove the security access cover 60 will cause the flange to automatically disconnect the socket 70 from the lamp 18 . The flange 76 may have text for instructing the individual to remove the plug prior to removing the cover 60 .
FIGS. 7 a and 7 b illustrate front and side views of a multi-lamp slide clip 80 . Multi-lamp slide clip 80 includes a plurality of openings 82 , for securing respective lamps 18 to a sidewall of a duct 15 or other casing, formed in an integral sheet of material, such as sheet metal. In the preferred embodiment, two slots 40 are positioned adjacent to each opening 82 . An angled extension 84 protrudes from the top of the slide clip 80 .
In operation, the multi-lamp slide clip 80 is used to secure multiple lamps 18 to a duct 15 or to other casing. Studs 48 and nuts 44 may be used to hold the multi-lamp slide clip 80 to the sidewall, as shown above in connection with FIG. 3 . The lamps 18 can be mounted straight (perpendicular to the sidewall) or at an angle. An angled mount can be achieved by using techniques described above, such as couplers 34 shown in FIG. 2 or by using two multilamp slide clips 80 in the configuration described in connection with FIGS. 5 a and 5 b.
The multi-lamp slide clip allows multiple lamps 18 to be easily installed and removed. The lamps 18 could be used for sterilization of a surface of a coil, a filter, or for general air sterilization.
An access cover such as that shown in FIGS. 6 a and 6 b could have multiple access holes 66 to cover the lamps secured with the multi-lamp slide clip.
The retaining assemblies described herein could be used not only to illuminate a rectangular coil, as shown in FIG. 1 a , but also with other coil designs, such as an A-coil, described in connection with U.S. Pat. No. 6,539,727 (U.S. Ser. No. 10/026,167) to Burnett, issued Apr. 1, 2003, entitled “Angled UV Fixture”, which is incorporated by reference herein. Additionally, the retaining assemblies could be used in other parts of the air conditioning system to purify filters and other surfaces, and to purify the air itself.
Although the Detailed Description of the invention has been directed to certain exemplary embodiments, various modifications of these embodiments, as well as alternative embodiments, will be suggested to those skilled in the art. The invention encompasses any modifications or alternative embodiments that fall within the scope of the Claims. | An angled germicidal lamp is used to illuminate a coil and drain pan for optimum energy utilization. An angled mount formed of two retention clips positions a germicidal lamp at a desired angle. A security access cover ensures that the germicidal lamp is disconnected from its power supply before access. Multiple germicidal lamps may be mounted by a single retention clip. | 5 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Application Ser. No. 61/043,589, filed Apr. 9, 2008, the details of which are hereby incorporated by reference as if fully set forth herein.
TECHNICAL FIELD
[0002] This application relates generally to warewasher systems which are used in commercial applications such as cafeterias and restaurants and, more particularly, to such a warewasher system including a heat recovery system with hot water supplement.
BACKGROUND
[0003] Commercial warewashers may include a heat recovery system that is installed in an outlet exhaust system of the warewasher to recover heat. The heat is usually transferred to the fresh water supply in the rinse cycle thus reducing the energy required to heat the water supply. However, upon system start up the exhaust system temperature is not sufficiently high to reach desired operating temperatures and the amount of time needed to wait for the source water to reach temperature can be objectionable.
SUMMARY
[0004] In an aspect, a warewasher for washing wares includes a housing defining an internal space with at least one spray zone for washing wares. A liquid delivery system provides a spray of liquid within the spray zone. A tank includes an inlet that is connected to a hot water source for filling the tank with hot water. The liquid delivery system receives water from the tank. An exhaust vents heated air from the housing. A final rinse system is connected to a cold water source. A heat recovery system is located between the final rinse system and the cold water source. The heat recovery system transfers heat from the exhaust air to the cold water provided from the cold water source. A valve associated with the hot water source selectively supplements the water exiting the heat recovery system with hot water from the hot water source.
[0005] In another aspect, a method of washing and rinsing wares by providing heated rinse water to a rinse station of a warewasher is provided. The method includes providing a spray of liquid to a spray zone within a housing using a liquid delivery system. A tank is filled with hot water from a hot water source and the liquid delivery system receiving water from the tank. Heated air is vented from the housing through an exhaust. A final rinse system is connected to a cold water source. Heat is transferred from the exhaust air to cold water provided from the cold water source using a heat recovery system located between the final rinse system and the cold water source. Water exiting the heat recovery system is selectively supplemented with hot water from the hot water source using a valve associated with the hot water source.
[0006] In another aspect, a warewasher for washing wares including a housing defining an internal space with at least one spray zone for washing wares. An exhaust path is provided for venting air from the housing. A liquid delivery system provides a spray of cleaning liquid within the spray zone. A final rinse system delivers a spray of rinse liquid for rinsing wares within the housing. A hot water booster feeds the final rinse system. A hot water booster filling arrangement includes a heat recovery system associated with the exhaust path. The heat recovery system is connected with a cold water input and arranged to transfer heat from exhaust air to cold water from the cold water input. An output of the heat recovery system is operatively connected to fill the hot water booster. A flow path delivers water from a hot water source to the hot water booster. A valve is located along the flow path. The valve is controlled to selectively deliver water from the hot water source to the hot water booster in dependence upon at least one monitored condition of the hot water booster filling arrangement.
[0007] The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a diagrammatic, section view of an embodiment of a warewash system;
[0009] FIG. 2 is a diagrammatic illustration of an embodiment of a heat recovery system with hot water supplement for use in the warewash system of FIG. 1 ;
[0010] FIG. 3 is a diagrammatic illustration of another embodiment of a heat recovery system with hot water supplement for use in the warewash system of FIG. 1 ; and
[0011] FIGS. 4 and 5 illustrate another embodiment of a heat recovery system with hot water supplement.
DETAILED DESCRIPTION
[0012] Referring to FIG. 1 , an exemplary conveyor-type warewash system, generally designated 10 , is shown. Warewash system 10 can receive racks 12 of soiled wares 14 from an input side 16 which are moved through tunnel-like chambers from the input side toward a dryer unit 18 at an opposite end of the warewash system by a suitable conveyor mechanism 20 . Either continuously or intermittently moving conveyor mechanisms or combinations thereof may be used, depending, for example, on the style, model and size of the warewash system 10 . The racks 12 of soiled wares 14 enter the warewash system 10 through a flexible curtain 22 into a pre-wash chamber or zone 24 where sprays of liquid from upper and lower pre-wash manifolds 26 and 28 above and below the racks, respectively, function to flush heavier soil from the wares. The liquid for this purpose comes from a tank 30 via a pump 32 and supply conduit 34 . A drain system 35 provides a location where liquid is pumped from the tank 30 using the pump 32 and where liquid can be drained from the tank, for example, for a tank cleaning operation.
[0013] The racks proceed to a next curtain 38 into a main wash chamber or zone 40 , where the wares are subject to sprays of cleansing liquid from upper and lower wash manifolds 42 and 44 with spray nozzles 47 and 49 , respectively, these sprays being supplied through a supply conduit 46 by a pump 48 , which draws from a main tank 50 . A heater 58 , such as an electrical immersion heater provided with suitable thermostatic controls (not shown), maintains the temperature of the cleansing liquid in the tank 50 at a suitable level. Not shown, but which may be included, is a device for adding a cleansing detergent to the liquid in tank 50 . During normal operation, pumps 32 and 48 are continuously driven, usually by separate motors, once the warewash system 10 is started for a period of time.
[0014] The warewash system 10 may optionally include a power rinse chamber or zone (not shown) that is substantially identical to main wash chamber 40 . In such an instance, racks of wares proceed from the wash chamber 40 into the power rinse chamber, within which heated rinse water is sprayed onto the wares from upper and lower manifolds.
[0015] The racks 12 of wares 14 exit the main wash chamber 40 through a curtain 52 into a final rinse chamber or zone 54 . The final rinse chamber 54 is provided with upper and lower spray heads 56 , 58 that are supplied with a flow of fresh hot water via pipe 60 under the control of fill valve 62 . A rack detector 64 is actuated when rack 12 of wares 14 is positioned in the final rinse chamber 54 and through suitable electrical controls, the detector causes actuation of the solenoid valve 62 to open and admit the hot rinse water to the spray heads 56 , 58 . The water then drains from the wares into tank 50 . The rinsed rack 12 of wares 14 then exit the final rinse chamber 54 through curtain 66 , moving into dryer unit 18 .
[0016] Referring now to FIG. 2 , the warewash system 10 is provided with a heat recovery system 70 that utilizes warm, humid air from within the system (e.g., typically at about 105° F. to 120° F., such as 114° F.) flowing through an exhaust 72 to heat cold water (e.g., typically at about 45° F. to 60° F., such as 50° F. or 55° F.) flowing from a cold water source 74 . The illustrated heat recovery system 70 includes a heat recovery coil 76 located within an exhaust conduit (represented by dashed lines 78 ) of the exhaust 72 . The heat recovery coil 76 is in a heat exchange relationship with the warm air flowing through the exhaust conduit 78 . In some embodiments, the heat exchange relationship between the heat recovery coil 76 and the heated air can provide a temperature increase in the water of about 40 to 45° F. or more. A booster heater 80 (e.g., an electric or steam booster heater) is in communication with the heat recovery coil 76 to receive water from the heat recovery coil. The booster heater 80 can provide a temperature increase to the water of about 40 to 80° F. The booster heater 80 then delivers the heated water to the final rinse station 54 , e.g., at a temperature of at least about 180° F.
[0017] As can be appreciated, during start-up or reactivation of the warewash system 10 , it takes time for the warm, humid air exiting the exhaust to reach temperature (e.g., about 114° F.). During this time, the water exiting the heat recovery coil 76 may not be sufficiently heated to reach the desired rinse temperature after leaving the booster heater 80 or the time period required for the booster heater to raise the water temperature to the desired rinse temperature may be deemed excessive.
[0018] A control valve 82 is provided to selectively and controllably mix hot water with water exiting the heat recovery coil 76 . A temperature sensor 86 is located downstream, but near the heat recovery coil 76 to monitor the temperature of water exiting the heat recovery coil. A controller 85 receives an indication from the temperature sensor 86 and responsively opens and closes the control valve 82 based on whether the water temperature is below a predetermined temperature (e.g., about 100 to 140° F., such as about 105° F. depending on the type of booster heater 80 ). In one embodiment, the control valve 82 is a fully open or fully closed type valve. In this embodiment, it may be desirable to size the control valve 82 to allow in enough hot water to assure water flowing into the booster heater 80 will be at or above the predetermined temperature, even in a no heat recovery case from the heat recovery coil. If the temperature of the water exiting the heat recovery coil 76 is below the predetermined temperature, the controller 85 opens the control valve 82 thereby allowing an amount of hot water from a hot water source 84 (e.g., boiler) to supplement the cooler water flowing from the heat recovery coil in order to raise the water temperature to at least the desired temperature. If the temperature of the water exiting the heat recovery coil 76 is at or above the predetermined temperature, the controller 85 closes the control valve 82 thereby preventing hot water from the hot water source from supplementing the water flowing from the heat recovery coil. The controller 85 can continuously monitor the water temperature of water exiting the heat recovery coil 76 to open and close the control valve 82 as needed. The hot water source 84 also provides hot water (e.g., at about 120° F.) to fill the tank 30 , 48 ( FIG. 1 ) for a washing operation. In an alternative embodiment, the control valve 82 may be a modulating control valve that continuously monitors temperature of water exiting the heat recovery coil 76 using a thermostat control 86 and responsively varies an amount of hot water allowed to mix with water exiting the heat recovery coil.
[0019] Referring now to FIG. 3 , an alternative warewash system 10 a includes a modulating control valve 82 a . The modulating control valve includes a thermostat control 86 a located downstream of mixing node N and upstream of the booster heater 80 . The modulating control valve 82 a varies the amount of hot water allowed to mix with the water exiting the heat recovery coil 76 based on the temperature detected by the thermostat control 86 a . If the water entering the booster heater 80 is less than the predetermined temperature, the rate of hot water allowed to supplement the water may be increased in order to reach the desired temperature. Because the temperature of the air flow through the exhaust 72 increases as the warewash system 10 warms up, the temperature of the water entering the booster heater 80 will rise. This rise in temperature of water entering the booster heater 80 is detected by the thermostat control 86 a , which will, in response, cause the control valve 82 to reduce the amount of hot water flowing therethrough as higher hot water flow rates will no longer be needed to reach the desired water temperature. The amount of hot water allowed to supplement the water exiting the heat recovery coil 76 may be continuously adjusted based on temperature of the water entering the booster heater 80 . In an alternative embodiment, the control valve 82 a may be a fully open and close type control valve.
[0020] FIG. 3 shows another alternative embodiment that includes a thermostat control 86 b (represented by dashed lines) located downstream of the booster heater 80 . Control valve 82 b is opened or closed (or continuously modulated) based on whether the final rinse water is above or below the predetermined temperature (e.g., of at least about 180° F.). The embodiment of FIG. 2 could likewise be modified to place the sensor 86 downstream of the booster heater 80 .
[0021] Referring now to FIGS. 4 and 5 , another warewash system embodiment 10 b is illustrated. In this embodiment, three valves 90 , 92 and 94 are used to control flow of water into the booster heater 80 . Valve 90 is associated with a low flow path 96 that receives water from the heat recovery coil 76 of the heat recovery system 70 , valve 92 is associated with a high flow path 98 that also receives water from the heat recovery coil of the heat recovery system and valve 94 is associated with a hot water path 100 that receives hot water from the hot water source 84 . Although not shown here, the hot water source 84 also fills the tank, as described above. A flow restrictor 102 is provided along the low flow path 96 for restricting flow of water therethrough when the valve 90 is open. A temperature sensor 104 is provided to monitor temperature of water flowing from the heat recovery coil 76 . Check valves 106 and 108 prevent back flow of water into the paths 96 , 98 and 100 .
[0022] When temperature of the water flowing from the heat recovery coil 76 is at or below a predetermined temperature (e.g., between 100° F. and 140° F., such as about 105° F.), the valve 90 associated with the low flow path 96 and the valve 94 associated with the hot water path 100 are opened (or allowed to remain open) and the valve 92 associated with the high flow path 98 is closed (or remains closed) such that only a small portion of the water entering the booster heater 80 comes from the heat recovery coil 76 and a majority of the water entering the booster heater 80 comes from the hot water source 84 . When the air in to the heat recovery system 70 (see arrow 110 ) heats the cold water flowing into the heat recovery coil 76 to or above the predetermined temperature, the valves 90 and 94 are closed and the valve 92 is opened such that all the water entering the booster heater 80 is provided from the heat recovery coil 76 .
[0023] As described above, the valves 90 , 92 and 94 are fully open or fully closed type valves. However, the valves 90 , 92 and 94 may be modulated valves. The valves 90 , 92 and 94 may be controlled by a controller 112 , for example, that receives a signal from the temperature sensor indicative of temperature. Or, for example, the valves 90 , 92 and 94 may be switched open or closed directly by a signal from the temperature sensor.
[0024] The above-described heat recovery systems with hot water supplement can be advantageous in a number of ways including during an initial start-up operation to reduce the amount of time needed for the final rinse water to reach the desired temperature of 180° F. For example, hot water may be used to supplement the water exiting the heat recovery coil 76 when the warewash system 10 is activated, but has been idle for some time. In certain embodiments, the thermostat control 86 may monitor water temperature only during an initial start up period, or the thermostat control may be used to continuously monitor water temperature throughout operation of the warewash system 10 . Hot water may be mixed with the water exiting the heat recovery coil 76 in situations where the heat recovery coil's efficiency has decreased, for example, due to clogging. In some embodiments, the hot water supplement may be used continuously to bring the water exiting the heat recovery coil 76 up to temperature. For example, in some buildings, the cold water source 74 may provide cold water at a temperature less than 50 degrees such that the temperature increase provided by the heated air in the exhaust 72 cannot bring the temperature of the water exiting the heat recovery coil to the desired temperature. In these instances, the water exiting the heat recovery coil 76 may be continuously supplemented with the hot water from the hot water source 84 . The above-described heat recovery system 70 may be used with a number of commercial warewashers such as the FT900 Flight Type warewasher or the C-Line warewasher, both commercially available from Hobart Corp., Troy Ohio. Significant energy savings can be realized without sacrificing high temperature rinse performance.
[0025] It is to be clearly understood that the above description is intended by way of illustration and example only and is not intended to be taken by way of limitation, and that changes and modifications are possible. For example, other configurations of heat recovery systems could be provided for transferring heat from the machine exhaust air to the incoming cold water (e.g., a heat pump arrangement). Further, while the downstream side of the hot water supplement control valve is shown and described as joining with the flow path of water exiting the heat recovery system, embodiments are contemplated in which the hot water flow path leads directly into the booster without pre-mixing with the water exiting the heat recovery system. Accordingly, other embodiments are contemplated and modifications and changes could be made without departing from the scope of this application. | A warewasher for washing wares includes a housing defining an internal space with at least one spray zone for washing wares. A liquid delivery system provides a spray of liquid within the spray zone. A tank includes an inlet that is connected to a hot water source for filling the tank with hot water. The liquid delivery system receives water from the tank. An exhaust vents heated air from the housing. A final rinse system is connected to a cold water source. A heat recovery system is located between the final rinse system and the cold water source. The heat recovery system transfers heat from the exhaust air to the cold water provided from the cold water source. A valve associated with the hot water source selectively supplements the water exiting the heat recovery system with hot water from the hot water source. | 0 |
CROSS-REFERENCES TO RELATED APPLICATIONS
This application claims priority of Japanese Patent Application No. 2006-029170, filed Feb. 7, 2006.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a system for charging battery cells used in portable electronic equipment and, in particular, to a charging system including a charger having a simplified structure for a battery pack including a processor.
2. Description of the Related Art
Lithium-ion batteries and nickel-hydride batteries, which have high energy densities, are often used in laptop personal computers (hereinafter referred to as laptop PCs), which are typical portable electronic equipment, because the laptop PCs require higher central processing unit (CPU) operating frequencies, longer operating times in mobile environments, and smaller sizes and lighter weights. To charge and discharge these batteries, recharge and discharge currents and voltages must be precisely controlled. Therefore, rather than conventional battery packs having only battery cells in a housing, battery systems called “smart batteries” are commonly used in which a microcomputer provided in the battery pack itself communicates with a laptop PC to exchange information while controlling charge and discharge.
Smart batteries are battery systems that are compliant with specifications called the Smart Battery System (SBS) specification proposed by Intel Corporation and Duracell Inc. in the United States. The first version, version 0.9, of the SBS specification was disclosed in 1995 and the latest version is Version 1.1. The SBS specification's main aim was to unify methods for controlling charge and discharge, measuring capacities, and communicating with laptop PCs, which had been being developed by laptop PC manufacturers on their own, to enable a battery pack itself to perform control of charge and discharge suitable to the chemical composition of the battery pack, thereby relieving the laptop PC designers of recharge/discharge control design work. Battery packs compliant with the SBS specification are referred to herein intelligent batteries.
An intelligent battery includes battery cells, which are the main unit to be charged and discharged, and electric circuitry including a CPU, a current measurement circuit, a voltage measurement circuit, and sensors contained on a substrate. In addition, the intelligent battery communicates with an embedded controller provided in a laptop PC through a data line. The intelligent battery can cooperate with the laptop PC to change a power consumption mode of the laptop PC in accordance with the remaining capacity of the battery or to shut off the laptop PC after displaying a warning on a display if remaining capacity becomes small or some abnormality occurs on the battery.
Two types of intelligent battery chargers, Level 2 and Level 3, are defined in the section “4.2 Smart Battery Charger Types” of the SBS specification “Smart Battery Charger Specification” Revision 1.1, released Dec. 11, 1998. In the case of the Level 2 battery charger, the intelligent battery is a master device and the battery charger is a slave device following the directions of the intelligent battery. The intelligent battery sends information about a current and voltage required for charging to the battery charger through a data line. The battery charger outputs a current and voltage based on the information. The Level 3 battery charger has a charger master operation mode in which the battery charger is the master device and the intelligent battery is the slave device following the battery charger. The Level 3 battery charger also has the battery master mode of the Level 2 battery charger. In the charger master mode, the battery charger sends an inquiry about a current and voltage required for charging to the intelligent battery and outputs a current and voltage according to a replay to it.
While a laptop PC equipped with a battery pack is being supplied with power from an alternating current (AC) power source, the battery pack is concurrently charged through a battery charger contained in the laptop PC. The laptop PC can then be used in a mobile environment. A user using a laptop PC in a mobile environment for a long time must charge spare battery packs beforehand. This requires many external battery chargers and places an extra cost burden on the user.
FIG. 7 shows a basic configuration of a conventional charging system. FIG. 7(A) shows a conventional battery pack 10 ′ attached to a laptop PC 100 being supplied with power from an AC power source. An AC adapter 123 is connected to the AC power source through an AC cord 125 , converts an AC voltage to a predetermined direct current (DC) voltage, and supplies power to the laptop PC 100 through a DC cable 127 . Power supplied to the laptop PC 100 is used by a system load of the laptop PC 100 and also used for charging the battery pack 10 ′. FIG. 7(B) shows the battery pack 10 ′ attached to and charged by an external battery charger 50 ′. The same AC adapter 123 that is attached to the laptop PC 100 is connected to the battery charger 50 ′.
FIG. 8 shows in detail the conventional battery pack 10 ′ shown in FIG. 7(A) attached to the laptop PC 100 . The battery pack 10 ′ is compliant with the SBS specifications. Provided in the battery pack 10 ′ are battery cells 11 and electronic components such as a microprocessor unit (MPU) 21 , a depletion field effect transistor (D-FET) 17 , a complementary field effect transistor (C-FET) 19 , a voltage regulator 23 , a thermistor 35 , a current measurement circuit 13 , and a voltage measurement circuit 15 . The battery pack 10 ′ is connected to the laptop PC 100 through five terminals: a positive terminal 37 , a C terminal 39 , a D terminal 41 , a T terminal 43 , and a negative terminal 45 . Power outputted from the battery cells 11 inside the battery pack 10 ′ is provided to the laptop PC 100 through the positive terminal 37 and the negative terminal 45 . The C terminal 39 and the D terminal 41 are connected to a clock terminal and a data terminal of the MPU 21 , respectively, and the T terminal is connected to the thermistor 35 .
The MPU 21 is an integrated circuit that operates on a constant voltage provided through the voltage regulator 23 . The MPU 21 may include a CPU of 8 to 16 bits or so, a RAM, a ROM, an analog input and output, a timer, and a digital input and output in one package. In addition, the MPU 21 may be capable of executing a program for controlling the battery pack 10 ′. The MPU 21 uses the current measurement circuit 13 and the voltage measurement circuit 15 to constantly monitor the current and voltage output from the battery 11 and controls the D-FET 17 for discharging of the battery 11 and the C-FET 19 for charging of the battery 11 . From the MPU 21 , a clock line and a data line lead to the embedded controller 115 of the laptop PC 100 through the C terminal 39 and D terminal 41 , respectively, so that the MPU 21 can communicate with the embedded controller 115 .
The resistance of the thermistor 35 changes in accordance with temperature. In one embodiment, the thermistor 35 is provided near the battery cells 11 and is connected to a voltage source Vcc through a pull-up resistance 121 of the laptop PC 100 , thereby functioning as a temperature measurement circuit. An output from the thermistor 35 is input into the embedded controller 115 through the T terminal 43 . The thermistor 35 is used for measuring the temperature of a battery.
The power management function of the laptop PC 100 is implemented by the embedded controller 115 together with a battery charger 117 , a control line 119 , a DC-DC converter 122 , and an AC adapter 123 . The embedded controller 115 is an integrated circuit that controls the power supply as well as many hardware components constituting the laptop PC 100 . The embedded controller 115 obtains information about the present current value and voltage value of the battery 11 through communication with the MPU 21 and, on the basis of the information, controls the battery charger 117 through the control line 119 to control charging of the battery pack 10 ′.
Power supplied from the AC adapter 123 and the battery pack 10 ′ is provided to components in the laptop PC through the DC-DC converter 122 . The embedded controller 155 is also connected onto an industry standard architecture (ISA) bus 113 , from which the embedded controller 155 is interconnected with and can communicate with a CPU 101 , a main memory 105 , and other hardware components constituting the laptop PC 100 through connections, including a peripheral component interconnect (PCI) bus 109 , a PCI-ISA bridge 111 , a CPU bridge 107 , and a front side (FS) bus 103 . Most of the other hardware components comprising the laptop PC 100 such as a display, a magnetic disk, an optical disk, and a keyboard are well known and therefore not shown in FIG. 8 .
FIG. 9 shows in detail the battery pack 10 ′ shown in FIG. 7(B) attached to an external battery charger 50 ′. The internal configuration of the battery pack 10 ′ is the same as that of the battery pack 10 ′ connected to the laptop PC 100 shown in FIG. 8 . The battery charger 50 ′ includes an MPU 116 , a switch (SW) 129 , a voltage regulator 51 , and a current regulator 53 . The MPU 116 plays a roll equivalent to the embedded controller 115 of the laptop PC 100 during charging the battery pack 10 ′. The MPU 116 obtains charging information such as the present current and voltage of the battery 11 through communication with the MPU 21 and, on the basis of the information, controls the SW 129 , the voltage regulator 51 , and the current regulator 53 to control charging in a manner similar to that in the laptop PC 100 .
The conventional external battery charger 50 ′ is capable of controlling charging of the battery pack 10 ′ in a manner similar to that used in the battery charger 117 incorporated in the laptop PC 100 . However, such an external battery charger 50 ′ is costly because it uses an MPU 116 . Therefore there is a demand for simplifying the structure of external battery chargers to reduce their costs.
SUMMARY OF THE INVENTION
From the foregoing discussion, there is a need for an apparatus, system, and method that charges a battery pack. Beneficially, such an apparatus, system, and method would simplify the structure of external battery chargers.
The present invention has been developed in response to the present state of the art, and in particular, in response to the problems and needs in the art that have not yet been fully solved by currently available battery charging methods. Accordingly, the present invention has been developed to provide a charging system and method for battery charging that overcome many or all of the above-discussed shortcomings in the art.
A charging system for a battery pack of the present invention is presented. In particular, the system, in one embodiment, includes an external battery charger and a battery pack. The external battery charger includes an identification circuit and a charging regulator. The external battery charger controls charging characteristics of the charging regulator in accordance with charging parameter values received from an external source.
The battery pack is attachable to an electronic apparatus having an identification circuit. In addition, the battery pack includes a battery cell and a processor capable of recognizing the identification circuit of the electronic apparatus and the identification circuit of the external battery charger and, upon recognizing the identification circuit of the external battery charger, sending the charging parameter values to the charging regulator. The charging system recognizes and sends the charging parameter values to the charging regulator to control charging of the battery pack, simplifying the structure of the external battery charger.
A method of the present invention is also presented for charging a battery pack. The method in the disclosed embodiments substantially includes the steps to carry out the functions presented above with respect to the operation of the described system.
A battery pack connects to an external battery charger. A processor of the battery pack recognizes that the processor is connected the external battery charger. The external battery charger provides charging parameters to the battery pack. The processor sends charging parameters to the external battery in response to recognizing that the processor is connected to the external battery charger. The method controls the controls the charging of the battery pack by the external battery charger with the charging parameters, simplifying the structure of the external battery charger.
References throughout this specification to features, advantages, or similar language do not imply that all of the features and advantages that may be realized with the present invention should be or are in any single embodiment of the invention. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention. Thus, discussion of the features and advantages, and similar language, throughout this specification may, but do not necessarily, refer to the same embodiment.
Furthermore, the described features, advantages, and characteristics of the invention may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize that the invention may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the invention.
The present invention charges battery packs with a simplified external battery charger structure. These features and advantages of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the advantages of the invention will be readily understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which:
FIG. 1 shows a configuration of a charging system to which an embodiment of the present invention is applied;
FIG. 2 shows a state in which a battery pack to which the present embodiment is applied is attached to a laptop PC;
FIG. 3 shows a state in which the battery pack to which the present embodiment is applied is attached to an external battery charger;
FIG. 4 shows a method for determining and controlling a charging voltage value and charging current value of an external battery charger to which the present embodiment is applied;
FIG. 5 is a flowchart showing operation of a program executed by an MPU in a battery pack to which the embodiment is applied;
FIG. 6 shows a charging voltage and a charging current during charging of a battery pack to which the present embodiment is applied;
FIG. 7 shows a configuration of a conventional charging system;
FIG. 8 shows a conventional battery pack attached to a laptop PC; and
FIG. 9 shows the conventional battery pack attached to an external battery charger.
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below in detail with respect to an embodiment shown in the accompanying drawings. FIG. 1 shows a configuration of a charging system to which an embodiment of the present invention can be applied. FIG. 1(A) shows a battery pack 10 attached to a laptop PC 100 being supplied with power from an AC power source. The laptop PC 100 operates on a DC voltage supplied from an AC adapter 123 and concurrently charges a laptop PC 10 . The AC adapter 123 converts an AC voltage supplied from a commercial power source through an AC cord 125 to a predetermined DC voltage and supplies the DC voltage to the laptop PC 100 through a DC cable 127 . The battery pack 10 is an intelligent battery compliant with the SBS specification. FIG. 1(B) shows the battery pack 10 attached to an external battery charger 50 being supplied with power from a commercial power source through the AC cord 125 . The battery charger 50 is integrated with an AC adapter and operates on AC power supplied directly through the AC cord 125 .
FIG. 2 shows in detail the battery pack 10 shown in FIG. 1 (A) attached to a laptop PC 100 . The laptop PC 100 is the same as the conventional laptop PC shown in FIG. 8 and therefore the description thereof will be omitted. The battery pack 10 is similar to the conventional battery pack 10 ′ shown in FIG. 8 and therefore only features of the present invention will be described.
The battery pack 10 includes a first selector switch (SW 1 ) 27 , a second selector switch (SW 2 ) 29 , a voltage setting section (Vset) 31 , and a current setting section (Iset) 33 in addition to the components of the conventional battery pack 10 ′. The circuitry has been modified so that a voltage of the thermistor 35 is input into an analog input A/D # 3 of an MPU 21 . The MPU 21 , provided inside the battery pack 10 , is capable of operating the first selector switch (SW 1 ) 27 and the second selector switch (SW 2 ) 29 . The first selector switch (SW 1 ) 27 couples one of an output of CLOCK terminal of the MPU 21 and an output of the voltage setting section (Vset) 31 to the C terminal 39 . The second selector switch (SW 2 ) 29 couples one of an output of DATA terminal of the MPU 21 and an output of the current setting section (Iset) 33 to the D terminal 41 . The output of the voltage setting section (Vset) 31 may be coupled to the D terminal 41 and the output of the current setting section (Iset) 33 may be coupled to the C terminal 39 . The voltage setting section (Vset) 31 and the current setting section (Iset) 33 will be described later.
When the battery pack 10 is connected to the laptop PC 100 , the MPU 21 operates the first selector switch (SW 1 ) 27 and the second selector switch (SW 2 ) 29 to connect the outputs of the CLOCK terminal and DATA terminal of the MPU 21 to the C terminal 39 and D terminal 41 , respectively. Consequently, a clock line and a data line are connected from the MPU 21 to the embedded controller 115 of the laptop PC 100 through the C terminal 39 and the D terminal 41 , respectively to enable communication between the MPU 21 and the embedded controller 115 . The battery pack 10 identifies that either the laptop PC 100 or the external barter charger 50 the battery pack 10 has been connected as will be described hereafter.
FIG. 3 shows in detail the battery pack 10 shown in FIG. 1(B) attached to the external battery charger 50 . The internal configuration of the battery pack 10 is the same as that of the battery pack connected to the laptop PC 100 shown in FIG. 2 . The external battery charger 50 includes a voltage regulator 51 , a current regulator 53 , a transformer 57 , and a pull-up resistance 121 ′ connected to a thermistor 35 through the T terminal 43 . The external battery charger 50 according to the present embodiment does not have an MPU and switches required by conventional external battery chargers. Furthermore, the external battery charger 50 according to the present embodiment includes the function of an AC adapter, which in the past has been separately provided for conventional external battery chargers. The external battery charger 50 of the present embodiment is capable of converting an AC voltage supplied from an AC power supply through the AC cord 125 to a DC voltage through use of the transformer 57 . In addition, the external battery charger 50 may adjust a voltage value and a charging current value using the voltage regulator 51 and the current regulator 53 . The pull-up resistance 121 ′ is connected to a voltage source Vcc having a voltage value equal to that of the laptop PC 100 but has a resistance different from that of the pull-up resistance 121 of the laptop PC 100 .
The parameters required for controlling charging of the battery pack 10 in a constant voltage constant current control (CVCC) mode are a charging voltage value and a charging current value. The type and physical characteristics of the battery cell 11 to be charged uniquely determine the charging voltage and current values. The voltage setting section (Vset) 31 generates a signal that provides a charge voltage value for charging the battery pack 10 to the external battery charger 50 . Similarly, the current setting section (Iset) 33 generates a signal that provides a charging current value for charging the battery pack 10 to the external battery charger 50 .
When the battery pack 10 is connected to the external battery charger 50 , the MPU 21 operates the first selector switch (SW 1 ) 27 and the second selector switch (SW 2 ) 29 to connect the output of the voltage setting section (Vset) 31 and the output of the current setting section (Iset) 33 to the C terminal 39 and the D terminal 41 , respectively. The voltage regulator 51 and the current regulator 53 receive the signals indicating the charging voltage value and the charging current value set by the voltage setting section (Vset) 31 and the current setting section (Iset) 33 through the C terminal 39 and the D terminal 41 , and adjust the charging voltage and current values to the charging voltage value and the charging current value to perform charging. A specific method for determining the charging voltage and current values will be described later.
The MPU 21 determines whether the charging has been completed on the basis of a charging current and voltage measured at a current measurement circuit 13 and a voltage measurement circuit 15 , respectively. If the MPU 21 determines that the charging has been completed, the MPU 21 turns off a D-FET 17 and a C-FET 19 to stop the charging of the battery pack 10 . The external battery charger 50 has a simplified structure and does not include a switch that turns off its output voltage.
A voltage value of the thermistor 35 is input in the analog input A/D # 3 of the MPU 21 . The thermistor 35 is connected to a voltage source Vcc through a pull-up resistance 121 ′ of the external battery charger 50 through the T terminal 43 . Since the pull-up resistance 121 ′ has a sufficiently high impedance, the voltage source Vcc does not influence temperature measurement by the embedded controller when the battery pack 10 is connected to the laptop PC 100 while the thermistor 35 is connected to the pull-up resistance 121 ′. The resistance values of the pull-up resistance 121 ′ of the external battery charger 50 and the pull-up resistance 121 of the laptop PC 100 are different, so that the voltage value input into the analog input A/D # 3 of the MPU 21 varies depending on whether the battery pack 10 is connected to the external battery charger 50 or the laptop PC 100 . The difference in the voltage value input into the A/D # 3 identifies which of the laptop PC 100 and the external battery charger 50 the battery pack 10 is connected to. Furthermore, the voltage value input in the A/D # 3 readily identifies a state in which the battery pack 10 is connected to neither the external battery charger 50 nor the laptop PC 100 . In that state, input and output of power are turned off by the D-FET 17 and the C-FET 19 mentioned above.
The MPU 21 identifies whether the battery pack 10 is connected to the external battery charger 50 or the laptop PC 100 from the voltage value input into the A/D # 3 . Therefore, various embodiments can be contemplated in addition to the example described above in which the external battery charger 50 and the laptop PC 100 differ in resistance values of pull-up resistance and/or voltage value of the voltage source Vcc. For example, the pull-up resistance values of the external battery charger 50 and the laptop PC 100 may be equal and the voltage values of the voltage sources Vcc may be different. In another example, both of the resistance values of the pull-up resistances and the voltage values of the voltage sources Vcc may differ between the external battery charger 50 and the laptop PC 100 .
The configuration of the battery pack 10 described above can be implemented by adding a few elements to a conventional battery pack 10 ′ and making modifications to firmware inside the MPU 21 to cause it to perform operation as shown in FIG. 5 , which will be described later. Thus, implementation of the battery pack 10 requires only minor modifications. Since the MPU 21 can also be omitted from the external battery charger 50 , the external battery charger 50 can be significantly simplified in structure and can be manufactured at a low cost accordingly. Terminals for connecting an intelligent battery to a laptop PC 100 can be used to connect the battery pack 10 to the external battery charger 50 . Therefore, no extra terminals need to be provided in the battery pack 10 and no modifications to software and hardware of the laptop PC 100 are required.
It should be noted that FIGS. 1 to 3 schematically show principle hardware configuration and connections for the purpose of illustrating the present embodiment. While many other electric circuits and devices are used in addition to these components to implement the battery pack 10 , external battery charger 50 , and laptop PC 100 , they are well known to those skilled in the art and therefore are not described herein. It will be understood that multiple blocks shown in FIGS. 1 to 3 may be integrated into a single integrated circuit or a single block may be separated into multiple integrated circuits. Such implementations also fall within the scope of the present invention as is well known to those skilled in the art.
FIG. 4 shows determining and controlling the charging voltage and current values in the external battery charger 50 to which the present embodiment is applied. As described above, the external battery charger 50 includes the function of an AC adapter and operates on an AC voltage directly supplied through the AC cord 125 . The AC voltage inputted through the AC cord 125 is first full-wave rectified by a rectifier bridge diode 71 on the primary side, and then smoothed by a capacitor 69 , and provided to a primary-side coil of a transformer 57 . Also provided on the primary side are a switching transistor 67 which makes switching operation on the voltage having been rectified and smoothed, a pulse width modulation (PWM) IC 65 which controls switching of the switching transistor 67 and provide a predetermined operation frequency, and a photo-transistor (TR 1 ) 63 which receives an output feedback from the secondary-side photodiode (PD 1 ) 61 and controls the periodicity of PWM in accordance with the level of the output voltage.
On the secondary side, a photodiode (PD 1 ) 61 for feeding outputs from the voltage regulator 51 and the current regulator 53 back to the primary side is provided in addition to the voltage regulator 51 and the current regulator 53 . Since the primary circuitry must be electrically separated from the secondary circuitry for safety reasons, a photocoupler is used between the photodiode (PD 1 ) 61 on the secondary side and the phototransistor (TR 1 ) 63 on the primary side.
A resistance R 13 31 provided inside the battery pack 10 functions as a voltage setting section (Vset) 31 that sets a charging voltage value Vchg. While the battery pack 10 is connected to the external battery charger 50 , a first selector switch (SW 1 ) 27 connects the resistance R 13 31 to a C terminal 39 . The difference between the charging voltage value Vchg and an actual charging voltage provided from the external battery charger 50 to the battery pack 10 is output from an operational amplifier AMP 11 in a voltage regulator 51 in the external battery charger 50 as the difference between a second reference voltage Vref 2 and the input voltage. Here, equation (1) given below holds in the voltage regulator 51 , where R 11 , R 12 , and R 13 are resistances, Vchg is the charging voltage vlue, and Vref 2 is the second reference voltage.
(
R
12
*
R
13
R
12
+
R
13
)
*
R
12
(
R
12
*
R
13
R
12
+
R
13
)
+
R
11
*
Vchg
=
Vref
2
(
1
)
From the equation, the following equation (2) can be derived and the charging voltage value Vchg can be established according to equation (2).
Vchg
=
Vref
2
*
(
1
R
12
+
R
11
R
12
+
R
13
+
R
11
2
*
R
12
)
(
2
)
Resistance R 3 provided in the battery pack 10 functions as a current setting section (Iset) 33 that sets a charging current value Ichg. When the battery pack 10 is connected to the external battery charger 50 , a second selector switch (SW 2 ) 29 connects R 3 to a D terminal 41 . The difference between the set charging current value Ichg and an actual charging current value provided from the external battery charger 50 to the battery pack 10 is output from an operational amplifier AMP 1 in a current regulator 53 in the external battery charger 50 as the difference between a reference voltage Vref 1 and the input voltage. Here, equation (3) given below holds in the current regulator 53 , where Rs, R 1 , R 2 , and R 3 are resistances, Ichg is the charging current value, and Vref 1 is the first reference voltage.
(
R
2
*
R
3
R
2
+
R
3
)
(
R
2
*
R
3
R
2
+
R
3
)
+
R
1
*
Vref
1
Rs
=
Ichg
(
3
)
From this equation, equation (4) given below can be derived and the charging current value Ichg can be established.
Ichg
=
(
R
2
R
1
*
R
2
R
3
+
R
1
+
R
2
)
*
Vref
1
Rs
(
4
)
As has been described above, the voltage setting section (Vset) 31 and the current setting section (Iset) 33 in the battery pack 10 in practice can set a charging voltage value and a charging current value according to equations (2) and (4) simply by setting resistance values R 3 and R 13 . Therefore, the battery pack 10 can be implemented at an extremely low cost.
If an excess voltage or current is generated, an output equivalent to the excess current outputted from the AMP 1 and an output equivalent to the excess voltage outputted from the AMP 11 are combined and output to the photodiode (PD 1 ) 61 . The output from the photodiode (PD 1 ) 61 is fed back to the power width modulator IC 65 on the primary side through the phototransistor (TR 1 ) 63 which forms a photocoupler. When feedback equivalent to an excess voltage or current is provided to the phototransistor (TR 1 ) 63 , the pulse width modulator IC 65 reduces the pulse width by means of the switching transistor 67 to reduce the period during which the switching transistor 67 is in the on state. Thus, the charging voltage value and the charging current value are controlled to a constant level. Methods for controlling the voltage value and current value by using pulse width modulation in a switching-regulator-based power supply unit used for an AC adapter for laptop PCs are well known to those of skill in the art. The external battery charger 50 according to the present embodiment can be readily implemented by adding a voltage regulator 51 and a current regulator 53 to the power supply unit so that outputs from the AMP 1 and AMP 11 are inputted into the photodiode (PD 1 ) 61 .
FIG. 5 is a flowchart of an operation of a program executed by the MPU 21 when the battery pack 10 described above is connected to the laptop PC 100 or the external battery charger 50 . The program is provided as firmware stored in the MPU 21 . It should be noted that the D-FET 17 and C-FET 19 are in the off state when the program shown in FIG. 5 is activated because the battery pack 10 turns off the D-FET 17 and C-FET 19 when the battery pack 10 is connected to neither the external battery charger 50 nor the laptop PC 100 .
First, when a voltage is input into the analog input A/D # 3 of the MPU 21 , it is determined that the battery pack 10 is likely to have been connected to the laptop PC 100 or the external battery charger 50 and the program is activated (block 301 ). Then, determination is made as to whether the battery pack 10 is connected to the laptop PC 100 or the external battery charger 50 (blocks 303 through 305 ). More specifically, if the voltage input into the analog input A/D # 3 indicates the resistance value of the pull-up resistance 121 ′ of the external battery charger 50 , it is determined that the battery pack 10 is connected to the external battery charter 50 . On the other hand, if the input voltage indicates the resistance value of the pull-up resistance 121 of the laptop PC 100 , it is determined that the battery pack 10 is connected to the laptop PC 100 . If the input voltage indicates neither of these values, it is determined that the battery pack 10 is connected to neither of the laptop PC 100 nor the external battery charger 50 and the process will end (block 339 ).
If it is determined that the battery pack 10 is connected to the laptop PC 100 , the first selector switch (SW 1 ) 27 and the second selector switch (SW 2 ) 29 are switched to connect the outputs of the CLOCK terminal and DATA terminal of the MPU 21 to the C terminal 39 and D terminal 41 , respectively (block 311 ). Then, the D-FET 17 and the C-FET 19 are turned on (block 313 ). As a result, communication between the MPU 21 and the embedded controller 115 is started (block 315 ). The battery pack 10 starts functioning as an intelligent battery (block 317 ) and then the operation of the program will end (block 339 ). The present current value and voltage value of the battery pack 10 are sent to the laptop PC 100 through communication between the MPU 21 and the embedded controller 115 . If the battery pack 10 needs to be charged, charging power is provided from a charger 117 on the laptop PC 100 .
On the other hand, if it is determined that the battery pack 10 is connected to the external battery charger 50 , determination is made first as to whether the battery pack 10 needs to be charged (blocks 321 and 323 ) on the basis of a current value and voltage value measured by a current measurement circuit 13 and a voltage measurement circuit 15 . If the battery pack 10 does not need to be charged, the operation of the program will end (block 339 ). If the battery pack 10 needs to be charged, the first selector switch (SW 1 ) 27 and the second selector switch (SW 2 ) 29 are switched to connect the outputs of the voltage setting section (Vset) 31 and the current setting section (Iset) 33 to the C terminal 39 and the D terminal 41 , respectively, (block 325 ) to set a charging voltage value and current value to be outputted. After the charging voltage and current values are set, the D-FET 17 and the C-FET 19 are turned on (block 327 ) to provide the set charging voltage and current values to the battery pack 10 , thereby staring charging of the battery pack 10 (block 329 ). On completion of the charging (block 331 ), the D-FET 17 and the C-FET 19 are turned off, thereby ending the charging (block 333 ), and the operation of the program will end (block 339 ).
FIG. 6 shows a charging voltage and a charging current during charging of the battery pack 10 . FIG. 6(A) is a block diagram of the battery pack 10 viewed from near the battery cells 11 during charging and shows where a voltage Vout and current lout are measured; FIG. 6(B) shows changes in the voltage Vout and the current Iout output from the external battery charger 50 . If the battery cells 11 are lithium-ion cells, charging is performed in a constant voltage/constant current control mode. Hereafter, the charging voltage value set by the voltage setting section (Vset) 31 is denoted by Vchg, the charging current value set by the current setting section (Iset) 33 is denoted by Ichg, the voltage across the cell is denoted by Vcell, and the DC resistance of the cell (excluding the DC resistance of the battery pack 10 ) is denoted by Rpk. The constant current period 201 is a time period during which charging is performed at a constant current value. As represented by curve 209 in FIG. 6(B) , the current lout is kept at the set current value Ichg during the constant current period 201 . The voltages Vout and Vcell gradually increase as represented by curves 205 and 207 . When the voltage Vcell reaches a value at which Equation (5) is satisfied, the voltage Vout becomes equal to the set voltage value Vchg and a constant voltage period 203 is entered.
Vchg=IchgRpk+V cell (5)
In the constant voltage period 203 , the voltage Vout remains at the set voltage value Vchg, the voltage Vcell gradually approaches Vchg, and the current lout gradually decreases. The voltage Vout becomes approximately equal to Vcell. When the current lout becomes equal to the set charging end current 211 , the charging of the battery pack 10 ends. The MPU 21 constantly monitors the values of Vcell and lout through the voltage measurement circuit 15 and the current measurement circuit 17 provided inside the battery pack 10 . When a charging end state is reached, the MPU 21 turns off the D-FET 17 and the C-FET 19 , thereby completing the charging.
The voltage value and current value suitable for charging a battery pack 10 vary depending on the structure and physical characteristics of the battery pack 10 . Conventionally, the MPU 21 of a battery pack 10 has indicated a charging voltage value and charging current value to be set to an external battery charger 50 through communication with the MPU of the external battery charger 50 . According to the present invention, internal resistance values in the voltage setting section and the current setting section are also set in the external battery charger 50 having an inexpensive and simple structure without an MPU, whereby each individual battery pack 10 can hold information about a voltage value and a current value suitable for charging of the battery pack 10 . This eliminates the need for providing different external battery chargers 50 for different types of battery packs 10 but instead a single external battery charger 50 can be used for charging many types of battery packs 10 .
Furthermore, according to the present embodiment, a charging voltage value and a charging current value can be readily set by using only internal resistance values in the voltage setting section and the current setting section. Therefore, if a single battery pack 10 requires multiple sets of charging voltage and charging current values, the charging voltage and charging current values can be set simply by selecting values from among multiple resistance values provided inside the voltage setting section and the current setting section by using selector switches. Since the numbers of switches and resistances in the battery pack 10 are only slightly increased, the manufacturing cost of the battery pack 10 is not significantly increased and an external battery charger 50 in the same embodiment described above may be used.
In an alternative embodiment, as a voltage setting section and a current setting section, voltages equivalent to a charging voltage and current values instead of resistance values may be directly provided from the analog output of the MPU 21 to a voltage regulator 51 and a current regulator 53 . The alternative embodiment also can be implemented by making slight modifications to firmware in the MPU 21 and switches in the battery pack 10 .
While the present invention has been described with respect to the specific embodiment shown in the drawings, the present invention is not limited to the embodiment shown in the drawings. It will be understood that any equivalent configurations may be used as long as they provide the effects of the present invention.
The present invention can be applied to a charging system including a battery pack 10 having an internal processor therein and an external battery charger 50 . In addition, the present invention may be embodied in other specific forms without departing from its spirit 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 system and method are disclosed for charging battery packs. A battery pack connects to an external battery charger. A processor of the battery pack recognizes that the processor is connected the external battery charger. The external battery charger provides charging parameters to the battery pack. The processor sends charging parameters to the external battery in response to recognizing that the processor is connected to the external battery charger. | 7 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for evaluating a crystalline semiconductor substrate, and more particularly to a method for evaluating a crystalline semiconductor substrate which includes a collector layer, a base layer, and an emitter layer and is used for heterojunction bipolar transistors.
2. Background Art
Heterojunction bipolar transistors (hereinafter referred to as HBTs) are widely used for power amplifiers for portable telephones, etc. since they provide good high-frequency characteristics and high current density. As its emitter-base junction, the HBT employs a heterojunction in which the emitter layer has a band gap larger than that of the base layer to enhance the emitter injection efficiency of the bipolar transistor. A semiconductor device made up of HBTs employs a semiconductor crystal substrate having a multilayer structure.
With reference to FIG. 9, a description will be made of a general cross-sectional structure of the semiconductor crystal substrate for HBTs, using an AlGaAs HBT as an example. As shown in the figure, the AlGaAs HBT includes a semiconductive GaAs substrate 32 , and an n-GaAs subcollector layer 33 , an n-GaAs collector layer 34 , a p-GaAs base layer 35 , an n-AlGaAs emitter layer 36 , and an n-GaAs contact layer 37 , which are all formed on the semiconductive GaAs substrate 32 in that order. These layers are formed by epitaxially growing each layer by use of, for example, the metalorganic chemical vapor deposition method (hereinafter referred to as the MOCVD method). Further in FIG. 9, reference numeral 38 denotes collector electrodes; 39 denotes base electrodes; and 40 denotes an emitter electrode. The collector electrodes 38 have a laminated structure made up of, for example, AuGe/Ni/Au. The base electrodes 39 , on the other hand, have a laminated structure made up of, for example, Pt/Ti/Au. Furthermore, the emitter electrode 40 is made of, for example, WSiN.
To enhance the high-frequency characteristics of an HBT configured as described above so that its characteristics are sufficient for a microwave device, the base resistance must be reduced by reducing the thickness of the p-type compound semiconductor crystal layer constituting the base layer and increasing the impurity concentration. For example, a known method for reducing the base resistance is to add, as an impurity, carbon to the p-GaAs layer, which is a p-type compound semiconductor crystal layer used as the base layer, in order to increase the carrier concentration of the base layer. In this method, however, hydrogen is undesirably taken into the base layer from ambient atmosphere in the base layer growth process. If hydrogen is included into the base layer, an initial change in the electrical characteristics, especially in the current gain is observed, which is disadvantageous to the quality control. This phenomenon is explained below using a specific example.
FIG. 10 shows the change in the current gain (β) of an HBT with changing base current (Ib). The HBT indicated by the figure has a base layer whose carrier concentration and hydrogen concentration are approximately 4×10 19 cm −3 and 2×10 19 cm −3 , respectively. The thickness of the base layer of the HBT is approximately 1,000 Å, and its emitter size is 4×20 μm. The change in the current gain (β) was measured five times on the same conditions. In the figure, the label “First measurement” indicates the characteristic curve measured for the first time immediately after the device was produced, while the label “Fifth measurement” indicates the characteristic curve measured for the fifth time.
As shown in FIG. 10, the current gain (β) changes with changing base current (Ib). Specifically, when the base current (Ib) is increased, the current gain (β) increases to a certain value and then decreases. The shapes of the curves of the current gains (β) measured immediately after energization for the first time and the fifth time are greatly different from each other when the current gains (β) increase. Specifically, the current gain (β) increases more rapidly as the number of times the device is energized increases. However, the maximum value of the current gain (β) measured for the first time is not largely different from that measured for the fifth time. Furthermore, the shapes of the curves obtained when the current gains (β) decrease are substantially the same.
The occurrence of the phenomenon shown in FIG. 10 that the current gain increases more rapidly with increasing number of energization operations is conceivably attributed to hydrogen included in the base layer of the HBT. That is, inclusion of hydrogen into the base layer of the HBT makes the electrical characteristics of the device extremely unstable, which is disadvantageous to the quality control of the semiconductor device. On the other hand, the change in the current gain with increasing number of energization operations becomes small for the fifth and later measurements, making the characteristics stabilized. However, inspecting the product after its characteristics have become stable takes considerable time, which is not preferable in terms of productivity.
Furthermore, conventionally, it is difficult to measure an initial change in the current gain at the time point when the crystal has been grown. That is, it is not possible to determine the initial change in the current gain until an HBT device is actually manufactured (from the grown crystal) and its electrical characteristics are evaluated. Such characteristics (as the current gain change) of a semiconductor crystal substrate cannot be determined without actually manufacturing an HBT device from it, raising the problem that it is not possible to perform the quality control at stages before the HBT is manufactured from the semiconductor crystal substrate.
SUMMARY OF THE INVENTION
The present invention has been devised in view of the above problems. It is, therefore, an object of the present invention to provide a method for evaluating a semiconductor crystal substrate in such a way that it is possible to estimate the initial change in the current gain of the semiconductor crystal substrate.
Another object of the present invention is to provide a method for evaluating a semiconductor crystal substrate in such a way that it is possible to perform quality control of an HBT device.
Other objects and advantages of the present invention will become apparent from the following description.
According to one aspect of the present invention, in a method for evaluating a semiconductor crystal substrate which includes a collector layer, a base layer, and an emitter layer and is used for a heterojunction bipolar transistor, a semiconductor crystal substrate to be evaluated which includes a crystal layer whose composition is the same as that of the base layer is produced. Excitation light is irradiated to the semiconductor crystal substrate to be evaluated and a change with time in an intensity of photoluminescence from the crystal layer is measured before the intensity becomes saturated. A change with time in a current gain of the heterojunction bipolar transistor produced using the semiconductor crystal substrate is measured based on the change with time in the intensity.
Other and further objects, features and advantages of the invention will appear more fully from the following description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a change in a base current with time depending on concentration of hydrogen.
FIG. 1B is a change in a base current with time depending on concentration of hydrogen.
FIG. 1C is a change in a base current with time depending on concentration of hydrogen.
FIG. 2A shows a cross section of a semiconductor substrate used for PL evaluation.
FIG. 2B shows a cross section of a semiconductor substrate used for PL evaluation.
FIG. 3A shows change in PL intensity with time depending on concentration of hydrogen.
FIG. 3B shows change in PL intensity with time depending on concentration of hydrogen.
FIG. 4A shows the relationship between base current and PL intensity.
FIG. 4B shows the relationship between base current and PL intensity.
FIG. 4C shows the relationship between base current and PL intensity.
FIG. 5 shows a cross section of a semiconductor crystal substrate according to the first embodiment.
FIG. 6 shows across section of a semiconductor crystal substrate according to the second embodiment.
FIG. 7 shows across section of a semiconductor crystal substrate according to the third embodiment.
FIG. 8 shows across section of a semiconductor crystal substrate according to the fourth embodiment.
FIG. 9 shows a cross section of a HBT device.
FIG. 10 shows the relationship between a base current and a current gain.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
The change in the current gain of an HBT shown in FIG. 10 is related to the hydrogen concentration in the base layer. This relationship will be described in detail with reference to FIG. 1 A˜FIG. 1 C. FIGS. 1A, 1 B, and 1 C each shows the change in the base current with time. Specifically, FIG. 1A shows the change in the base current with the concentration of the hydrogen contained in the base layer set to 1×10 19 cm −3 ; FIG. 1B shows the change with the concentration set to 4× 10 18 cm −3 ; and FIG. 1C shows the change with the concentration set to 1×10 18 cm −3 . All of the curves shown in FIG. 1 A˜FIG. 1C were obtained with the collector-emitter voltage and the base-emitter voltage fixed to 2.5V and 1.3V, respectively. As shown in the figures, the higher the hydrogen concentration, the larger the change in the base current with time. The current gain (β), the base current (Ib), and the collector current (Ic) are related by the following formula,
β=Δ Ic/ΔIb.
It should be noted that a similar phenomenon is observed in photoluminescence (hereinafter abbreviated as PL) evaluation, which will be described below in detail.
PL is a light-emitting phenomenon which occurs when minority carries (electrons in the case of a p-type semiconductor) within a semiconductor recombine with holes (or electrons) and thereby form electron-hole pairs after the minority carriers are excited by irradiating to the semiconductor a light having a wavelength with energy larger than the forbidden energy band gap.
FIGS. 2A and 2B each shows a semiconductor crystal substrate used for PL evaluation. The semiconductor crystal substrate shown in FIG. 2A comprises a GaAs substrate 1 , and an i-GaAs layer 2 , an i-In 0.5 Ga 0.5 P layer 3 (200 Å thick), a C-doped p-GaAs layer 4 (carrier concentration: 4×10 19 cm −3 , thickness: 1,000 Å), an n-In 0.5 Ga 0.5 P layer 5 (carrier concentration: 3×10 17 cm −3 , thickness: 200 Å), and an i-GaAs layer 6 (200 Å thick), which are all formed on the GaAs substrate 1 in that order. The semiconductor crystal substrate shown in FIG. 2B, on the other hand, comprises a GaAs substrate 7 , and an i-GaAs layer 8 , an i-In 0.8 Ga 0.2 As layer 9 (500 Å thick), a C-doped p-GaAs layer 10 (carrier concentration: 4×10 19 cm −3 , thickness: 1,000 Å), an n-In 0.5 Ga 0.5 P layer 11 (carrier concentration: 3×10 17 cm −3 , thickness: 1,000 Å), and an i-GaAs layer 12 (200 Å thick), which are all formed on the GaAs substrate 7 in that order.
In FIGS. 2A and 2B, the p-GaAs layers 4 and 10 in which carbon is doped as a p-type impurity correspond to the base layers of the HBTs. In the semiconductor crystal substrate shown in FIG. 2A (hereinafter referred to as Sample I), the concentration of the hydrogen contained in the p-GaAs layer 4 is 1×10 19 cm −3 . In the semiconductor crystal substrate shown in FIG. 2B (hereinafter referred to as Sample II), on the other hand, the concentration of the hydrogen contained in the p-GaAs layer 10 is 4×10 18 cm −3 . The impurity concentrations of the p-GaAs layers 4 and 10 in Sample I and Sample II, respectively, are both 4×10 19 cm −3 . Furthermore, the thicknesses of the p-GaAs layers 4 and 10 are both approximately 1,000 Å, which is approximately equal to the thicknesses of the base layers of the HBTs.
FIG. 3 A and FIG. 3B show PL intensities measured at room temperature using an Ar ion laser (light) having a wavelength of 488 nm as an excitation light source. FIG. 3A shows PL intensities of Sample I shown in FIG. 2A, while FIG. 3B shows PL intensities of Sample II shown in FIG. 2 B. In each figure, the horizontal axis indicates the excitation time, and the vertical axis indicates the PL intensity. In FIG. 3 A and FIG. 3B, the PL wavelength is 897 nm, which corresponds to the forbidden energy band gap of GaAs. The value of the PL intensity increases with time and becomes constant from a certain time point, reaching the saturation point. The change in the PL intensity of Sample I from the start of the measurement to the saturation point is larger than that for Sample II. That is, the higher the concentration of the hydrogen contained in the base layer, the longer the time required for the PL intensity to reach its saturation point. Furthermore, regardless of the hydrogen concentration, the PL intensity increases with increasing excitation light intensity.
A description will be made below of the relationship between the base current and the PL intensity. FIGS. 4A, 4 B, and 4 C each shows the time dependences of the base current and the PL intensity of a semiconductor crystal substrate whose base layer has a different hydrogen concentration. Specifically, FIG. 4A shows the time dependences of the base current and the PL intensity with the hydrogen concentration set to 1×10 19 cm −3 ; FIG. 4B shows the time dependences with the hydrogen concentration set to 4×10 18 cm −3 ; and FIG. 4C shows the time dependences with the hydrogen concentration set to 1×10 18 cm −3 . Furthermore, the base currents are measured with the collector-emitter voltage and the base-emitter voltage fixed to 2.5 V and 1.3 V, respectively. The PL intensities, on the other hand, are measured at room temperature with the excitation light intensity set to approximately 3.8 kW/cm 2 using an Ar ion laser (light) having a wavelength of 488 nm. The changes in the intensity of the PL wavelength (λ=897) were plotted. As shown in the figures, as the concentration of the hydrogen contained in the base layer becomes higher, the changes in the base current and in the PL intensity increase and the time required for the base current and the PL intensity to saturate also increases. Therefore, the change in the PL intensity of a semiconductor crystal substrate over time can be measured to determine the change in the base current over time, that is, the change in the current gain of the HBT device over time.
Incidentally, the hydrogen concentration of the base layer of an HBT is decided by the base layer growth conditions. Therefore, the PL intensity may be measured before actually manufacturing the device, and the base layer growth conditions may be determined based on the measurements to control the quality of the device. Conventionally, a device is actually produced to measure its base current. The production of the device takes at least approximately half a day. The quality control by use of the above PL intensity measurement, on the other hand, does not require the production of the device, and furthermore the PL intensity measurement itself takes only a few minutes, which leads to a significant reduction in the entire working hours. Furthermore, the present invention inspects a semiconductor crystal substrate instead of the actual HBT device, making it possible to carry out nondestructive inspection of the HBT device to measure its electrical properties.
For example, assume that the PL intensity of a semiconductor crystal substrate is measured with an excitation light intensity of 3.8 kW/cm 2 using an Ar ion laser (light) having an excitation wavelength of 488 nm. Letting the PL saturation intensity value (the value of the PL intensity when it no longer changes with time in FIG. 3 A˜ 3 B, or FIGS. 4 A˜ 4 C) be 1, if the value of the measured PL intensity reaches 0.95 or more within 50 seconds from the start of the measurement, the initial change in the current gain will be within 5%, which means that the semiconductor crystal substrate is suitable for manufacture of a device.
It should be noted that the relationship between the current gain and the PL intensity of an HBT is described in Japanese Patent Application Laid-open No. Hei 3-64943. The patent utilizes the correlations among the PL intensity, the carrier lifetime, and the current gain, and measures the lifetime of the PL after the saturation of the PL intensity in order to measure the lifetime of the carriers in the base layer. However, the lifetime of PL is generally on the order of a few tens of picoseconds. This means that the above literature only measures such a short time to obtain the lifetime of specific PL (and the lifetime of the carriers in the base layer).
The present invention, on the other hand, is characterized in that it utilizes the correlations among the current gain change, the base current change, and the PL intensity change over time. Specifically, the present invention aims to measure how the PL intensity (which indicates the lifetime of the PL) changes in units of a few tens of seconds before its saturation, instead of measuring the lifetime of the PL itself after the saturation of the PL intensity. Therefore, there is no need for measuring time-resolved PL on the order of picoseconds; it is only necessary to monitor the change in the PL intensity with time on the order of seconds.
First Embodiment
The present embodiment characteristically uses the semiconductor crystal substrate shown in FIG. 5 as a sample and measures its PL intensity. It should be noted that the term “sample” hereinafter indicates a semiconductor crystal substrate to be evaluated. A semiconductor crystal substrate to be evaluated includes a crystal layer corresponding to a base layer used for manufacturing an actual HBT.
In an actual HBT, since the emitter layer, the contact layer, etc. are formed on the base layer, PL emitted from the base layer is absorbed by these layers and as a result, PL of a low intensity can be only observed. To solve this problem, the present invention uses a sample made up of a GaAs substrate 13 , an undoped GaAs layer 14 , and a p-GaAs layer 15 doped with carbon as a p-type impurity. The undoped GaAs layer 14 and the p-GaAs layer 15 are formed on the GaAs substrate 13 in that order. Alternatively, the p-GaAs layer 15 may be directly formed on the GaAs substrate 13 . In the present embodiment, the p-GaAs layer 15 corresponds to the base layer of the HBT, and light emitted from this layer is observed to measure the time dependence of the PL intensity. Since the present invention does not form any other layer on the layer corresponding to the base layer, it is possible to reduce the absorption of PL by other layers, resulting in measurement with sufficient intensity. Furthermore, since the configuration of the sample is very simple, it can be easily produced at low cost.
A sample of the present embodiment can be produced, for example, through epitaxial growth using the MOCVD method. The carrier concentration of the p-GaAs layer 15 is preferably set to approximately from 1×10 18 cm −3 to 1×10 20 cm −3 . Its thickness is preferably set to approximately from 500 Å to 10,000 Å. A thickness thinner than 500 Å results in low PL intensity, while a thickness thicker than 10,000 Å leads to high cost. Both cases are undesirable.
The wavelength (λ) of excitation light used for the PL measurement is preferably set to from 300 nm to 550 nm. For example, an Ar ion laser (light) having a wavelength of 488 nm may be used for the measurement. On the other hand, since the main wavelength (λ) of PL at room temperature (25° C.) is from 890 nm to 900 nm, it is desirable to use this wavelength to monitor the PL intensity.
Second Embodiment
The present embodiment characteristically uses the semiconductor crystal substrate shown in FIG. 6 as a sample and measures its PL intensity. A p-GaAs layer 18 doped with carbon as a p-type impurity corresponds to the base layer of the HBT. The present invention is characterized in that barrier layers 19 and 17 are formed over and under the p-GaAs layer 18 , respectively. As used herein, the term “barrier layer” is a layer which functions to confine excited minority carriers and thereby increase the PL intensity. A material to be used for a barrier layer must have a forbidden energy band gap larger than that of the p-GaAs layer. That is, another semiconductor layer having a forbidden energy band gap larger than that of the p-GaAs layer is bonded to each of the top and the bottom surfaces of the p-GaAs layer so that an energy barrier can be formed due to the difference between these forbidden energy band gaps. The formation of this energy barrier makes it difficult for the carriers within the p-GaAs layer (that is, the electrons and holes) to leave the layer, confining them therein. With this arrangement, the electrons and the holes in the base later can be efficiently recombined together, making it possible to increase the PL intensity.
Materials such as In 0.5 Ga 0.5 P and Al 0.3 Ga 0.7 As can be used for the barrier layers for the present embodiment. These materials may be doped or undoped. Further, the barrier layers formed over and under the p-GaAs layer may be made of the same material or different materials. Still further, barrier layers need not be formed both over and under the p-GaAS layer. A barrier layer may be formed only either over or under the p-GaAs layer.
A sample of the present embodiment can be produced, for example, through epitaxial growth using the MOCVD method. The carrier concentration of the p-GaAs layer 18 is preferably set to approximately from 1×10 18 cm −3 to 1×10 20 cm −3 . Its thickness is preferably set to approximately from 500 Å to 10,000 Å. A thickness thinner than 500 Å results in low PL intensity, while a thickness thicker than 10,000 Å leads to high cost. Both cases are undesirable.
Unlike the first embodiment, the present embodiment is characterized in that the barrier layers 19 and 17 are formed over and under the p-GaAs layer 18 , respectively. Therefore, the thicknesses of the barrier layers 17 and 19 are preferably each set to approximately from 100 Å to 1,000 Å to reduce the absorption by the barrier layers 17 and 19 of PL emitted from the p-GaAs layer 18 .
The wavelength (λ) of excitation light used for the PL measurement is preferably set to from 300 nm to 550 nm. For example, an Ar ion laser (light) having a wavelength of 488 nm may be used for the measurement. On the other hand, since the main wavelength (λ) of PL at room temperature (25° C.) is from 890 nm to 900 nm, it is desirable to use this wavelength to monitor the PL intensity.
Third Embodiment
The present embodiment characteristically uses the semiconductor crystal substrate shown in FIG. 7 as a sample and measures its PL intensity. That is, the present embodiment is characterized in that it measures a sample having the same configuration as that of the semiconductor crystal substrate constituting an actual HBT. Therefore, according to the present embodiment, a sample HBT device can be actually produced from a measured sample (semiconductor crystal substrate), making it possible to obtain accurate information on the electrical characteristics of an HBT device to be produced by using the semiconductor crystal substrate beforehand. Furthermore, since the formation of the base layer of an actual HBT is affected by lattice defects in the crystal layers formed under the base layer, the use of a sample according to the present embodiment having the same configuration as that of an actual semiconductor crystal substrate makes it possible to carry out more accurate evaluation.
As shown in FIG. 7, a semiconductor crystal substrate according to the present embodiment comprises a GaAs substrate 20 , and an n + -GaAs layer 21 , an n-GaAs layer 22 , a p-GaAs layer 23 , an n-barrier layer 24 , and an n-GaAs layer 25 , which are all formed on the GaAs substrate 20 in that order. The p-GaAs layer 23 is doped with carbon as a p-type impurity. These layers can be formed through epitaxial growth using the MOCVD method. The carrier concentration of the p-GaAs layer 23 is preferably set to from 1×10 18 cm −3 to 1×10 20 cm −3 , and its thickness is preferably set to approximately from 500 Å to 10,000 Å. A thickness thinner than 500 Å results in low PL intensity, while a thickness thicker than 10,000 Å leads to high cost. Both the cases are undesirable. On the other hand, the carrier concentration of the n + -GaAs layer 21 is preferably set to 1×10 18 cm −3 or more, and its thickness is preferably set to 500 Å or less. Materials such as In 0.5 Ga 0.5 P and Al 0.3 Ga 0.7 As can be used for the n-barrier layer 24 . The carrier concentration of the n-barrier layer 24 is preferably set to from 1×10 17 cm −3 to 5×10 17 cm −3 , and its thickness is preferably set to approximately from 100 Å to 500 Å. Furthermore, the carrier concentrations of the n-GaAs layers 22 and 25 are preferably set to 1×10 17 cm −3 or less, and their thicknesses are preferably set to 2,000 Å or more.
The wavelength (λ) of excitation light used for the PL measurement is preferably set to from 300 nm to 550 nm. For example, an Ar ion laser (light) having a wavelength of 488 nm may be used for the measurement. On the other hand, since the main wavelength (λ) of PL at room temperature (25° C.) is from 890 nm to 900 nm, it is desirable to use this wavelength to monitor the PL intensity.
Fourth Embodiment
The present embodiment characteristically uses the semiconductor crystal substrate shown in FIG. 8 as a sample and measures its PL intensity. A p-GaAs layer 29 doped with carbon as a p-type impurity corresponds to the base layer of the HBT. The present invention is characterized in that a barrier layer 28 is formed under the p-GaAs layer 29 . A material to be used for a barrier layer must have a forbidden energy band gap larger than that of the p-GaAs layer. With this arrangement, an energy barrier is produced due to the difference between these forbidden energy band gaps, making it possible to confine the carriers within the base layer so that the electrons and the holes can be efficiently recombined together, increasing the intensity of PL from the base layer.
Further, since the configuration of the sample (semiconductor crystal substrate) of the present embodiment is similar to that of the semiconductor crystal substrate of an actual HBT device, it is possible to obtain accurate information on the electrical characteristics of the actual HBT device to be produced by using the sample semiconductor crystal substrate beforehand. Furthermore, since the formation of the base layer of the actual HBT is affected by lattice defects in the crystal layers formed under the base layer, the present embodiment makes it possible to carry out more accurate evaluation also in this respect.
As shown in FIG. 8, a semiconductor crystal substrate according to the present embodiment comprises a GaAs substrate 26 , and an n + -GaAs layer 27 , an n-barrier layer 28 , a p-GaAs layer 29 , an n-barrier layer 30 , and an n-GaAs layer 31 , which are all formed on the GaAs substrate 26 in that order. The p-GaAs layer 29 is doped with carbon as a p-type impurity. These layers can be formed through epitaxial growth using the MOCVD method. The carrier concentration of the p-GaAs layer 29 is preferably set to approximately from 1×10 18 cm −3 to 1×10 20 cm −3 , and its thickness is preferably set to approximately from 500 Å to 10,000 Å. A thickness thinner than 500 Å results in low PL intensity, while a thickness thicker than 10,000 Å leads to high cost. Both the cases are undesirable. On the other hand, the carrier concentration of the n + -GaAs layer 27 is preferably set to 1×10 18 cm −3 or more, and its thickness is preferably set to 500 Å or less. Furthermore, the carrier concentration of the n-GaAs layers 28 and 31 are preferably set to 1×10 17 cm −3 or less, and their thicknesses are preferably set to 2,000 Å or more.
Materials such as In 0.5 Ga 0.5 P and Al 0.3 Ga 0.7 As can be used for the barrier layers for the present embodiment. The barrier layers formed over and under the C-doped GaAs layer may be made of the same material or different materials. Further, the carrier concentrations of the barrier layers are preferably set to from 1×10 17 cm −3 to 5×10 17 cm −3 , and their thicknesses are preferably set to approximately from 100 Å to 500 Å.
The wavelength (λ) of excitation light used for the PL measurement is preferably set to from 300 nm to 550 nm. For example, an Ar ion laser (light) having a wavelength of 488 nm may be used for the measurement. On the other hand, since the main wavelength (λ) of PL at room temperature (25° C.) is from 890 nm to 900 nm, it is desirable to use this wavelength to monitor the PL intensity.
The features and advantages of the present invention may be summarized as follows.
According to one aspect, it is possible to determine the change in the base current of an HBT with time, that is, the change in the current gain of the HBT with time, by measuring the change in the PL intensity of a semiconductor crystal substrate with time.
According to another aspect, since no other layer is formed on a layer corresponding to a base layer, it is possible to reduce the absorption of PL by other layers, resulting in measurement with sufficient intensity.
According to another aspect, it is possible to efficiently recombine electrons and holes together within a base layer, resulting in increased PL intensity.
According to another aspect, since a sample HBT device can be actually produced from a measured sample (semiconductor crystal substrate) it is possible to obtain accurate electrical information on an HBT device to be produced by using the semiconductor crystal substrate beforehand.
According to another aspect, it is possible to efficiently recombine electrons and holes together within a base layer, resulting in increased PL intensity. Furthermore, since a sample HBT device can be actually produced from a measured sample (semiconductor crystal substrate), it is possible to obtain accurate electrical information on an HBT device to be produced by using the semiconductor crystal substrate beforehand.
According to another aspect, it is possible to efficiently recombine electrons and holes together within a base layer, resulting in increased PL intensity.
According to other aspect, it is possible to determine the change in the base current of an HBT device with time, that is, the change in the current gain of the HBT device with time, by measuring the change in the intensity of PL from a p-type GaAs crystal layer doped with carbon with time.
Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may by practiced otherwise than as specifically described.
The entire disclosure of a Japanese Patent Application No. 2002-228514, filed on Aug. 6, 2002 including specification, claims, drawings and summary, on which the Convention priority of the present application is based, and incorporated herein by reference in its entirety. | In a method for evaluating a crystalline semiconductor substrate which includes a collector layer, a base layer, and an emitter layer and is used for a heterojunction bipolar transistor, a layer is provided having the same composition as the base layer. The semiconductor substrate is irradiated with excitation light and change with time in intensity of photoluminescence from the layer is measured before the intensity becomes saturated. The change with time in current gain of the heterojunction bipolar transistor produced using the semiconductor substrate is determined from the change with time in the intensity. | 6 |
FIELD OF THE INVENTION
[0001] The present invention relates to a method and an apparatus for controlling sleep mode in wireless communication networks; and, more particularly, to a method and an apparatus for maximizing power saving by lengthening sleep duration through adoption of the N-ary exponential sleep mode of a base station and a mobile station in the wireless communication networks.
BACKGROUND OF THE INVENTION
[0002] In general, a communication system has been developed to provide high quality service capable of transmitting and receiving massive data at high speeds. In particular, demands for wireless communication network environments have recently increased. Due to a limited battery life of a mobile station (hereinafter, referred to as “MS”), power consumption of the MS is one of the factors significantly affecting overall performance of the wireless communication systems.
[0003] Sleep mode of a base station (hereinafter, referred to as “ES”) and an MS can be employed to efficiently reduce power consumption of the MS. For example, the IEEE 802.16e standard for communication systems supports sleep mode, which is mandatory for the BS. Further, implementation of sleep mode is optional for the MS according to the IEEE 802.16e standard, however, the MS not supporting sleep mode keeps monitoring the downlink all the time even when it does not receive data from the BS or transmit data to the BS, resulting in high power consumption.
[0004] Sleep mode is composed of repetition of a sleep interval and a listening interval. The sleep interval is the time duration when the MS does not receive downlink data for power saving, whereas the listening interval is the time duration when the MS receives instruction for the existence of downlink traffic addressed to the MS. During the sleep interval, the MS may not supply power to some of the physical components and it does not communicate with the BS.
[0005] FIG. 1 illustrates the operation for controlling sleep mode in a communication system.
[0006] As shown in FIG. 1 , an MS 100 transmits a sleep request (MOB_SLP-REQ) message to a BS 120 to switch from active mode to sleep mode in step S 141 . On receiving this MOB_SLP-REQ message, the BS 120 determines whether to approve the switching request of the MS 100 to sleep mode or not, and transmits a sleep response message (MOB_SLP-RSP) depending on the determined result to the MS 100 in step S 143 . For example, according to the IEEE 802.16e standard, this MOB_SLP-RSP message contains several parameters such as initial-sleep window indicating the length of an initial sleep interval; listening window indicating the length of a listening interval; final-sleep window base indicating a base for a final sleep interval and final-sleep window exponent indicating an exponent for the final sleep interval, which are necessary to determine the maximum length of a sleep interval; and start_frame_number indicating the number of the starting frame of the initial sleep interval. In step S 143 , the BS 120 may request the MS 100 to start sleep mode by sending a sleep response (MOB_SLP-RSP) message without receiving a sleep request message from the MS 100 , which is called an unsolicited manner. Upon reception of the MOB_SLP-RSP message, the MS 100 goes to sleep mode at the beginning frame M of the initial sleep interval, and the sleep mode lasts for the length of the initial sleep interval N 1 . After the sleep interval, the MS 100 enters a listening interval with a length of L.
[0007] During the listening interval, the BS 120 transmits a message instructing the MS 100 to switch to access mode if there is any downlink data destined for the MS 100 , whereas the BS 120 transmits a message instructing to remain in sleep mode to the MS 100 if there is no downlink data.
[0008] Subsequently, during the listening interval right after the initial sleep interval, the BS 120 transmits a traffic indication (MOB_TRF-IND) message with negative indication for the MS 100 since the BS 120 has decided there is no downlink data for the MS 100 in step S 145 . This MOB_TRF-IND message with negative indication does not require the identification of the MS 100 and the MS 100 having received this message continues its sleep mode. The length of the next sleep interval of the MS 100 is 2×N 1 , which is a double of the length of the previous sleep interval. That is, if a MOB_TRF-IND message contains negative indication for the MS 100 , the length of the next sleep interval of the MS 100 doubles the length of the previous sleep interval until it reaches up to a maximum length N 2 of the sleep interval. After the sleep interval has ended, the MS 100 enters a listening interval with a length of L. For example, the sleep interval and the listening interval as described above are defined by Power Saving Class of type I in the IEEE 802.16e standard.
[0009] Thereafter, if provided with a protocol data unit (PDU) for the MS 100 , that is, if the BS 120 determines that there is downlink data intended for the MS 100 , it transmits a traffic indication (MOB_TRF-IND) message with positive indication for the MS 100 in step S 147 . This MOB_TRF-IND message with positive indication has the identification of the MS 100 . The MS 100 having received this message switches to access mode, thereby receiving the downlink data.
[0010] In the wireless communication networks, while the BS and the MS perform normal operations in access mode for data transmission or reception, they may enter sleep mode by minimizing the data transmission or reception in order to save power, thereby reducing power consumption of the MS.
[0011] The method for controlling sleep mode described above by referring to FIG. 1 is called the binary exponential algorithm. This algorithm is known to be adequate for a packet-by-packet service, which stores data as a unit of packet in a buffer of the BS and transmits packets to mobile subscribers.
[0012] FIG. 2A shows a configuration of sleep mode when the IEEE 802.16e communication system employs the binary exponential algorithm, whereas FIG. 25 shows a configuration of sleep mode when the IEEE 802.16m communication system employs the binary exponential algorithm. In the IEEE 802.16e communication system as shown FIG. 2A , the length of each listening interval L is identical, whereas if there is no downlink data intended for the MS 100 , then the length of a sleep interval So is doubled to S 1 and S 1 is doubled to S 2 , and so on. In the IEEE 802.16m communication system as shown FIG. 2B , an initial sleep cycle C 0 consisting of a sleep interval is extended twice to the next sleep cycle C 1 consisting of a listening interval L and a sleep interval S. If there is no downlink data intended for the MS 100 , then C 1 is extended to C 2 , and so on. If there is any downlink data intended for the MS 100 , then during the listening interval, the data can be delivered to the MS 100 .
[0013] In recent years, the communication systems have been developed to provide a high data rate service and have operated a scheduler to transmit multiple (bulk) packets or variable length packets to an MS at a time.
[0014] However, if the conventional binary exponential algorithm is applied to these latest communication systems, power efficiency achieved by the sleep mode is reduced since transitions between access mode and sleep mode are unnecessarily frequent, it may degrade overall performance of the wireless communication systems.
SUMMARY OF THE INVENTION
[0015] The present invention has been conceived to solve the problems described above and it is, therefore, an object of the present invention to provide a method and an apparatus for maximizing power saving by lengthening sleep duration through adoption of the N-ary exponential sleep mode of a BS and an MS in the wireless communication network, where N is set to be equal to or greater than 2, and in particular, if N=2 then it corresponds to the conventional binary exponential sleep mode.
[0016] In accordance with an aspect of the prevent invention, there is provided a method for controlling sleep mode of a base station and a mobile station in wireless communication networks. The method includes: determining N of the N-ary exponential sleep mode to decide a length of sleep duration including a sleep interval, where N is equal to or greater than 2; measuring the amount of downlink traffic addressed to the mobile station at the beginning of a listening interval right after the sleep interval; when there exist downlink traffic but m times additional consecutive sleep duration is not expired, confirming whether the measured amount of the downlink traffic satisfies a mode transition condition; conducting a sleep interval of the next sleep duration of which the length is determined by multiplying the length of the current sleep duration by N unless the measured amount of the downlink traffic satisfies the mode transition condition; and transmitting the downlink traffic to the mobile station when m times the additional consecutive sleep duration is expired or when the measured amount of the downlink traffic satisfies the mode transition condition even when m times the additional consecutive sleep duration is not expired.
[0017] In accordance with another aspect of the present invention, there is provided an apparatus for controlling sleep mode of a mobile station in a wireless communication network, including: an N-value decision unit for determining N of the N-ary exponential sleep mode to decide a length of sleep duration including a sleep interval, where N is equal to or greater than 2; a traffic measuring unit for measuring an amount of downlink traffic for the mobile station stored in a buffer at the beginning of a listening interval right after the sleep interval; a mode transition determination unit for determining the mode transition by confirming whether the measured amount of the downlink traffic satisfies a mode transition condition when there exist downlink traffic but m times additional consecutive sleep duration is not expired; a sleep duration managing unit for conducting a sleep interval of the next sleep duration, the length of the next sleep duration being determined by multiplying the length of the current sleep duration by N based on the determination of the mode transition determination unit; and a packet control unit for transmitting the downlink traffic to the mobile station when m times the additional consecutive sleep duration is expired or according to the determination of the mode transition determination unit even when m times the additional consecutive sleep duration is not expired.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The above and other objects and features of the present invention will become apparent from the following description of embodiments given in conjunction with the accompanying drawings, in which:
[0019] FIG. 1 is a signal flow chart for illustrating the operation for controlling sleep mode in a communication system;
[0020] FIG. 2A presents a configuration of sleep mode when the binary exponential algorithm is applied to a communication system based on the IEEE 802.16e standard;
[0021] FIG. 2B shows a configuration of sleep mode when the binary exponential algorithm is applied to a communication system based on the IEEE 802.16m standard;
[0022] FIG. 3 is a flow chart describing a method for controlling sleep mode in accordance with the first embodiment of the present invention;
[0023] FIG. 4 shows a flow chart describing a method for controlling sleep mode in accordance with the second embodiment of the present invention;
[0024] FIG. 5 is a flow chart describing a method for controlling sleep mode in accordance with the third embodiment of the present invention; and
[0025] FIG. 6 illustrates a block diagram of a sleep mode controlling apparatus provided in a base station for performing methods for controlling sleep mode in accordance with the embodiments of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0026] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings which form a part hereof.
[0027] The present invention provides a method and an apparatus for controlling sleep mode of a BS and an MS in a wireless communication network. Although the present invention is described with a wireless communication system based on the IEEE 802.16e standard and a wireless system based on the IEEE 802.16m standard, the method and the apparatus of the present invention can be applied to other communication systems. Furthermore, although the present invention is described with a BS and a single MS, the method and the apparatus of the present invention can be applied to multiple MSs as well.
[0028] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0029] FIG. 3 is a flow chart describing a method for controlling sleep mode in a wireless communication network in accordance with the first embodiment of the present invention.
[0030] First, in step S 201 , a BS and an MS 700 determine various parameters necessary for the mode transition operation. For example, a length of initial sleep duration T 0 , the length of the maximum sleep duration T max , the number of additional consecutive sleep duration m upon arrival of packets, the maximum N-ary exponent I max , the length of a time-out for retransmission R, the maximum number of allowed retransmissions N max , the required transmission delay constraint D* and the size of multiple packets M can be determined. Here, the length of the sleep duration corresponds to the length of each sleep interval S 0 , S 1 or S 2 in the wireless communication system based on the IEEE 802.16e standard shown in FIG. 2A , whereas it corresponds to the length of each sleep cycle C 0 , C 1 or C 2 in the wireless communication system based on the IEEE 802.16m standard shown in FIG. 2B .
[0031] That is, the sleep duration means sleep mode with a variable length such as a sleep interval or a sleep cycle in wireless communication systems based on various standards. The above parameters can be determined by a sleep request (MOB_SLP-REQ) message and a sleep response (MOB_SLP-RSP) message exchanged between the BS and the MS. For example, if the MS transmits a sleep request MOB_SLP-REQ message to the BS for the mode transition operation, the BS determines whether to approve transition to sleep mode by using variables contained in the MOB_SLP-REQ message and then transmits a sleep response (MOB_SLP-RSP) message with the decision to the MS, or not. Otherwise, the BS transmits a sleep response (MOB_SLP-RSP) message to the MS in an unsolicited manner. This transmitted message contains both parameters of step S 201 and N determined as follows.
[0032] After that, in step S 203 , N of the N-ary exponent for the sleep duration is determined using the various parameters. N is used to decide the length of the next sleep duration by multiplying the current sleep duration by N.
[0033] The value of N needs to be determined to minimize power consumption as well as to satisfy the quality of service for transmission delay constraint. For this, N satisfying the following Equation 1 is chosen.
[0000] ( m×N I max T 0 )+( N max ×R )≦ D* Eq. 1
[0034] In Equation 1, m is the number of the additional consecutive sleep duration upon arrival of packets, I max is the maximum N-ary exponent, T 0 is the length of the initial sleep duration, N max is the maximum number of allowed retransmissions, R is the length of a time-out for retransmission, and D* is the transmission delay constraint. Here, by collecting packets which arrived during m times the maximum sleep duration determined under the worst-case delay constraint and sending the multiple packets to the MS in downlink, the MS continues its sleep mode for m-times longer sleep duration, thereby saving extra power.
[0035] Next, in step S 205 , the consecutive sleep duration parameter K is initialized to 1.
[0036] The sleep duration with a length determined above is proceeded in step S 207 . Initially, the sleep duration is set to T 0 . During the sleep duration, the ES does not send downlink data to the MS. If the wireless communication network provides any protocol data unit for the MS during the sleep duration, the BS stores downlink traffic for the MS in a buffer.
[0037] Thereafter, in step S 209 , whether the current sleep duration has expired or not is determined. When the sleep duration with a length determined above is not expired, then the sleep duration continues and the process described above is repeated.
[0038] When the sleep duration has expired, then a listening interval begins in step S 211 .
[0039] Next, n step S 213 , the existence of downlink traffic for the MS stored in the buffer is checked when the listening interval starts. When there is no traffic, the method goes to step S 215 where the ES transmits the MS a traffic indication message with negative indication for the MS to conduct the sleep duration.
[0040] Subsequently, in step S 217 , the length of the next sleep duration is determined right after the current listening interval. The length of the next sleep duration is decided by using N determined as in step S 203 . When the maximum exponent is greater than I max , it is fixed to I max . As shown in Equation 2, the length of the next sleep duration T next is determined by multiplying the length of the current sleep duration T cur by N. Here, the length of the next sleep duration T next is limited to the length of the maximum sleep duration T max .
[0000] T next =N×T cur , where T next ≦T max Eq. 2
[0041] After the length of the next sleep duration T next is decided in step S 217 , the method returns to step S 207 in which the next sleep duration T next is proceeded.
[0042] On the other hand, if the BS has decided that there is traffic in step S 213 , then it is checked, in step S 219 , whether or not the consecutive sleep duration parameter K reaches to the number of additional consecutive sleep duration m.
[0043] If K does not reach to m, in step S 221 , whether or not the amount of the measured downlink traffic satisfies the mode transition condition is decided. Here, either whether the number of downlink data packets satisfies the mode transition condition or whether the amount of downlink data satisfies the mode transition condition can be adopted.
[0044] As for whether the number of downlink data packets satisfies the mode transition condition or not, the following Equation 3 is used for decision making.
[0000] N pkt ≧M Eq. 3
[0045] In Equation 3, N pkt is the number of the packets stored in the buffer and M is the threshold value representing the maximum number of packets allowed for one-time downlink transmission.
[0046] As for whether the amount of downlink data satisfies the mode transition condition or not, the following Equation 4 is used for decision making.
[0000] N bit ≧N th Eq. 4
[0047] In Equation 4, N b i t is the number of the transmitted bits and N th is a threshold value representing the maximum allowable number of the transmitted bits in a given time.
[0048] When the BS determines that the mode transition condition is not satisfied in step S 221 , the BS increases K by 1 in step S 223 and then transmits the MS a traffic indication message with negative indication for the MS to conduct the sleep duration in step S 215 .
[0049] On the other hand, if K reaches to m in step S 219 , the BS transmits the MS a traffic indication message with positive indication for the MS for the mode transition and transmits the downlink data stored in the buffer to the MS in step S 225 and then it switches to initial sleep mode I step S 227 .
[0050] Although not shown in FIG. 3 , if there is uplink data from the MS after the BS transmits the downlink data stored in the buffer to the MS, the BS may receive the uplink data from MS. When the BS transmits the MS the downlink data stored in the buffer, the parameter M or the threshold value Nth of the maximum allowable number of transmitted bits may be fixed, varied or unlimited. In case of the fixed or varied value, data conforming to the amount of data bits or the number of data packets assigned to the MS is transmitted. In case of the unlimited value, all of the stored downlink traffic is transmitted.
[0051] Further, although not shown in FIG. 3 , a time-out can follow after the data transmission or reception is completed.
[0052] FIG. 4 is a flow chart describing a method for controlling sleep mode in a wireless communication network in accordance with the second embodiment of the present invention when a wireless communication system based on the IEEE 802.16e standard is employed.
[0053] First, in step S 301 , a BS and an MS determine various parameters required for the mode transition operation. For example, the length of an initial sleep interval S 0 , the length of the maximum sleep interval S max , the number of additional consecutive sleep intervals m upon arrival of packets, the maximum N-ary exponent I max , the length of a time-out for retransmissions R, the maximum number of allowed retransmissions N max , the required transmission delay constraint D and the threshold value M for the maximum number of packets allowed for one-time downlink transmission can be determined.
[0054] The above parameters can be determined by a sleep request (MOB_SLP-REQ) message and a sleep response (MOB_SLP-RSP) message exchanged between the BS and the MS. For example, if the MS transmits a sleep request MOB_SLP-REQ message to the BS for the mode transition operation, the BS determines whether to approve transition to sleep mode by using variables contained in the MOB_SLP-REQ message and then transmits a sleep response (MOB_SLP-RSP) message with the decision to the MS. Otherwise, the BS transmits a sleep response (MOB_SLP-RSP) message to the MS in an unsolicited manner. This transmitted message contains both parameters determined in step S 301 and N determined in step S 303 as follows.
[0055] In step S 303 , N of the N-ary exponent for the sleep interval is determined using the various parameters. N is used to determine the length of the next sleep interval by multiplying_the current sleep interval by N. N needs to be determined to minimize power consumption as well as to satisfy the quality of service for a given transmission delay constraint. For this, N satisfying the following Equation 5 is chosen.
[0000] ( m×N I max S 0 )+( N max ×R )≦ D* Eq. 5
[0056] In Equation 5, m is the number of the additional consecutive sleep interval upon arrival of packets, I max is the maximum N-ary exponent, So is the length of an initial sleep interval, N max is the maximum number of allowed retransmissions, R is the length of a time-out for retransmission, and D* is the required transmission delay constraint.
[0057] Next, the consecutive sleep interval parameter K is initialized to 1 in step S 305 and then the sleep interval with a length determined above begins in step S 307 .
[0058] Initially, the sleep interval is set with So. During the sleep interval, the BS does not send downlink data to the MS. If the wireless communication network provides any protocol data unit for the MS during the sleep interval, the BS stores downlink traffic for the MS in a buffer.
[0059] Thereafter, in step S 309 , whether the current sleep interval has expired or not is determined. When the frames do not reach up to the sleep interval with a length determined above, then the method returns to step S 307 to continue the sleep interval and repeat the process described above.
[0060] However, when the current sleep duration has expired, then a listening interval starts in step S 311 .
[0061] Next, in step S 313 , the existence of downlink traffic for the MS stored in the buffer is checked when the listening interval begins. If there is no traffic, in step S 315 , the BS transmits the MS a traffic indication message with negative indication for the MS to conduct the sleep interval.
[0062] The length of the next sleep interval is determined following right after the current listening interval. The length of the next sleep interval is decided by using N determined in step S 303 . When the maximum exponent is greater than I max , it is fixed to I max . As shown in Equation 6, the length of the next sleep interval S next is determined by multiplying the length of the current sleep interval S cur by N. Here, the length of the next sleep interval S next is limited to the length of the maximum sleep interval S max .
[0000] S next =N×S cur , where S next ≦S max Eq. 6
[0063] After that, in step S 317 , the length of the next sleep interval S next is decided, and the method returns to step S 307 to start the next sleep interval S next .
[0064] On the other hand, however, if the ES has decided that there is traffic in step S 313 , then it checks whether or not the consecutive sleep interval parameter K reaches to the number of additional consecutive sleep intervals m in step S 319 .
[0065] When K does not reach to m, whether or not the amount of the measured downlink traffic satisfies the access mode transition condition is decided in step S 321 . Here, either whether the number of downlink data packets satisfies the access mode transition condition or whether the amount of downlink data satisfies the access mode transition condition can be adopted.
[0066] As for whether the number of downlink data packets satisfies the access mode transition condition, the following Equation 7 is used for decision making.
[0000] N pkt ≧M Eq. 7
[0067] In the Equation 7, N pkt is the number of the packets stored in the buffer and M is the threshold value requesting the maximum number of packets allowed for one-time downlink transmission.
[0068] As for whether the amount of downlink data satisfies the access mode transition condition, the following Equation 8 is used for decision making.
[0000] N bit ≧N th Eq. 8
[0069] In the Equation 8, N bit is the number of the transmitted bits and N th is a threshold value for the maximum allowable number of transmitted bits in a given time.
[0070] When the BS determines that the access mode transition condition is not satisfied in step S 321 , the BS increases K by 1 in step S 323 and then transmits the MS a traffic indication message with negative indication for the MS to conduct the sleep interval in step S 315 .
[0071] On the other hand, when K reaches to m in step S 319 , the BS transmits the MS a traffic indication message with positive indication for the MS for the mode transition to access mode and transmits the downlink data stored in the buffer to the MS in step S 325 .
[0072] After completing the transmission of the downlink data, the BS switches to initial sleep mode in step S 327 and goes back to step S 305 .
[0073] Although not shown in FIG. 4 , if there is uplink data from the MS after the BS transmits the downlink data stored in the buffer to the MS, the BS may receive the uplink data from MS. When the BS transmits the MS the downlink data stored in the buffer, the parameter value of M or the threshold value Nth for the maximum allowable number of transmitted bits can be fixed, varied or unlimited. In case of the fixed or varied value, data conforming to the amount of data bits or the number of packets assigned to the MS is transmitted. In case of the unlimited value, all of the measured downlink traffic is transmitted.
[0074] Although not shown in FIG. 4 , a time-out can follow after the transmission and reception of data is completed.
[0075] FIG. 5 is a flow chart describing a method for controlling sleep mode a wireless communication network in accordance with the third embodiment of the present invention when a wireless communication system based on the IEEE 802.16m standard is employed.
[0076] First, in step S 401 , a BS and an MS determine various parameters required for the mode transition operation. For example, the length of an initial sleep cycle Co, the length of the maximum sleep cycle C max , the number of additional consecutive sleep cycles m upon arrival of packets, the maximum Nary exponent I max , the length of a time-out for retransmission R, the maximum number of allowed retransmissions N max , the required transmission delay constraint D* and the threshold value M for the maximum number of packets allowed for one-time downlink transmission can be determined.
[0077] The above parameters can be determined by a sleep request (MOB_SLP-REQ) message and a sleep response (MOB_SLP-RSP) message exchanged between the BS and the MS. For example, if the MS transmits a sleep request MOB_SLP-REQ message to the BS for the mode transition operation to sleep mode, the BS determines whether to approve transition to sleep mode by using variables contained in the MOB_SIP-REQ message and then transmits a sleep response (MOB_SLP-RSP) message with the decision to the MS. Otherwise, the BS transmits a sleep response (MOB_SLP-RSP) message to the MS in an unsolicited manner. This transmitted message contains both parameters of step S 401 and N determined as follows.
[0078] In step S 403 , N of the N-ary exponent for the sleep cycle is determined by using the various parameters. N is used to decide the length of the next sleep cycle by multiplying the current sleep cycle by N. The value of N needs to be determined to minimize power consumption as well as to satisfy the quality of service for q given transmission delay constraint. For this, N satisfying the following Equation 9 is chosen (S 403 ).
[0000] ( m×N T max C 0 )+( N max ×R )≦ D* Eq. 9
[0079] In Equation 9, m is the number of the additional consecutive sleep cycle upon arrival of packets, I max is the maximum N-ary exponent, Co is the length of initial sleep cycle, N max is the maximum number of allowed retransmissions, R is the length of a time-out for retransmission, and D* is the required transmission delay constraint.
[0080] Next, the consecutive sleep cycle parameter K is initialized to 1 in step S 405 and then whether or not the previously determined sleep cycle is the initial sleep cycle is checked in step S 407 . Initially, the sleep cycle is set with C 0 .
[0081] When the sleep cycle is the initial sleep cycle, in step S 409 , the sleep mode lasts until the sleep cycle is expired. During the sleep mode, downlink data is not sent to the MS from the BS. When the wireless communication network provides any protocol data unit for the MS during the sleep mode, the BS stores downlink traffic for the MS in a buffer.
[0082] Thereafter, the length of the next sleep cycle is determined. The length of the next sleep cycle is decided by using N determined as in step S 403 . When the maximum exponent is greater than I max , it is fixed to I max . As shown in the Equation 10, the length of the next sleep cycle C next is determined by multiplying the length of the current sleep cycle C cur by N. Here, the length of the next sleep cycle C next is limited to the length of the maximum sleep cycle C max as follows.
[0000] C next =N×C cur , where C next ≦C max Eq. 10
[0083] Accordingly, the length of the next sleep cycle C next is determined in step S 411 .
[0084] Meanwhile, when the sleep cycle is not the initial sleep cycle, in step S 413 , a listening interval of the sleep cycle begins. In this step, a single frame is used for the listening interval.
[0085] Next, in step S 415 , the existence of downlink traffic for the MS stored in the buffer is checked when the listening interval starts. When there is no traffic, the method returns to step S 409 where the BS transmits the MS a traffic indication message with negative indication for the MS to conduct the sleep duration.
[0086] On the other hand, however, when the BS has detected that there is traffic in step S 415 , then it checks whether or not the consecutive sleep cycle parameter K reaches to the number of additional consecutive sleep cycle m in step S 417 .
[0087] When K does not reach to m, in step S 419 , whether or not the amount of the measured downlink traffic satisfies the access mode transition condition is decided. Here, either whether the number of downlink data packets satisfies the access mode transition condition or whether the amount of downlink data satisfies the access mode transition condition can be adopted.
[0088] As for whether the number of downlink data packets satisfies the access mode transition condition, the following Equation 11 is used for decision making.
[0000] N pkt ≧M Eq. 11
[0089] In Equation 11, N pkt is the number of the packets stored in the buffer and M is the threshold value requesting the maximum number of packets allowed for one-time downlink transmission.
[0090] As for whether the amount of downlink data satisfies the access mode transition condition, the following Equation 12 is used for decision making.
[0000] N bit ≧N th Eq. 12
[0091] In Equation 12, N b j t is the number of the transmitted bits and N th is a threshold value for the maximum allowable number of the transmitted bits in a given time.
[0092] When the BS determines that the access mode transition condition is not satisfied in step S 419 , the BS increases K by 1 in step S 421 and then transmits the MS a traffic indication message with negative indication for the MS to conduct the sleep mode in step S 409 .
[0093] On the other hand, when K reaches to m in step S 417 or if the mode transition condition is satisfied in step S 419 , the method advances to step S 423 . In step S 423 , the BS transmits the MS a traffic indication message with positive indication for the MS for traffic transmission. Then, the BS sets the length of the current sleep cycle C cur to the length of the initial sleep cycle C 0 and then initializes the consecutive sleep cycle parameter to 1. Next, in step S 425 , while keeping the listening interval, the BS transmits the downlink data stored in the buffer to the MS. When the BS transmits the MS the downlink data stored in the buffer, the parameter value of M or the threshold value Nth for the maximum allowable number of transmitted bits can be fixed, varied or unlimited. In case of the fixed or varied value, data conforming to the amount of data bits or the number of packets assigned to the MS is transmitted. In case of the unlimited value, all of the measured downlink traffic is transmitted.
[0094] Then, in step S 427 , whether or not the current sleep cycle including the listening interval of step S 425 is expired is decided.
[0095] When the current sleep cycle has expired in step S 427 , then the method returns to step S 411 where the length of the next sleep cycle is determined. When the current sleep cycle has not expired, whether or not the buffer is empty is then checked in step S 429 . The listening interval of the current sleep cycle lasts until the buffer is completely emptied. When the buffer is emptied, the sleep mode continues until the current sleep cycle ends in step S 431 .
[0096] FIG. 6 as a block diagram of a sleep mode control apparatus 500 provided in a BS for implementing methods for controlling sleep mode in accordance with the embodiments of the present invention.
[0097] As shown in FIG. 6 , a sleep mode controlling unit 500 includes a sleep duration managing unit 510 , a traffic measuring unit 520 , a mode transition determination unit 530 , an N-value decision unit 540 and a packet control unit 550 .
[0098] The sleep duration managing unit 510 determines the length of sleep duration in sleep mode to enter and then conducts a sleep interval of the sleep duration. The sleep duration managing unit 510 stores downlink traffic for an MS 700 in the buffer if a protocol data unit for the MS 700 is provided from a wireless communication network. The sleep duration managing unit 510 conducts a listening interval when the current sleep interval has expired. Here, the sleep duration managing unit 510 determines the length of the next sleep duration by multiplying the length of the current sleep duration by N provided from the N-value decision unit 540 .
[0099] The traffic measuring unit 520 measures the amount of the downlink traffic for the MS 700 stored in the buffer at the beginning of the listening interval. As described above, the amount of the downlink traffic for the MS 700 can be measured in terms of the number of downlink data packets or the amount of downlink data bits, e.g., the number of data bits, addressed to the MS 700 stored in the buffer at the beginning of the listening interval. Upon arrival of packets, extending the current sleep duration by up to m times allows more packets to arrive.
[0100] The mode transition determination unit 530 determines whether or not to send a traffic indication message with positive indication or to send a traffic indication message with negative indication based on either the measured amount of the downlink traffic or reaching the number of the additional consecutive sleep duration m. For example, when the measured amount of the downlink traffic does not satisfy the mode transition condition, the mode transition determination unit 530 transmits the MS 700 a traffic indication message with negative indication for the MS 700 during a listening interval so that the MS 700 can enter a sleep interval. On the other hand, when the measured amount of the downlink traffic satisfies the mode transition condition or when the number of the additional consecutive sleep duration m has been reached, the mode transition determination unit 530 transmits the MS 700 a traffic indication message with positive indication for the MS 700 during a listening interval to manage mode transition such as packet transmission.
[0101] The N-value decision unit 540 determines N of the sleep duration by using various parameters required for the mode transition operation and provides it to the sleep duration managing unit 510 . Here, N can be sent to the sleep duration managing unit 510 either directly or via the mode transition determination unit 530 . N is used to determine the length of the next sleep duration by multiplying the length of the current sleep duration by N and it needs to minimize power consumption as well as to satisfy the quality of service for a given transmission delay constraint. For this, the length of the initial sleep duration, the number of the additional consecutive sleep duration, the maximum N-ary exponent, the maximum allowable number of retransmissions, the length of a time-out for retransmission and the transmission delay constraint are considered to determine N. Here, these various parameters requi 8 red for the mode transition operation can be determined by a sleep request message and a sleep response message exchanged between the BS and the MS 700 .
[0102] The packet control unit 550 performs the following operation in sleep mode or access mode. The packet control unit 550 controls the BS to transmit the downlink data stored in the buffer to the MS 700 . When there is uplink data from the MS 700 , the packet control unit 550 controls the BS to receive the uplink data from the MS 700 and when the transmission and reception of the data is completed, it conducts a time-out as described above.
[0103] The sleep mode controlling apparatus 500 performs the methods for controlling sleep mode described with respect to the embodiments described by referring to FIGS. 3 to 5 . A detailed description thereof will be omitted to avoid redundancy since it can be readily implemented by those skilled in the art by using the description referring to FIGS. 3 to 5 .
[0104] In accordance with the embodiments of the present invention, power consumption due to too frequent mode transition caused when the wireless communication network supports sleep mode of the BS and MS can be reduced. Power saving can be significantly increased by lengthening a sleep cycle through adoption of the N-ary exponential sleep mode considering a multiple packet transmission technique as well as satisfying the required delay constraint for each service flow, where N is set to be equal to or greater than 2. In particular, if N=2 then it corresponds to the conventional binary exponential sleep mode.
[0105] Furthermore, power consumption of the MS can be reduced without hardware modification in broadband wireless access communication systems based on the IEEE 802.16e and 802.16m standards.
[0106] While the invention has been shown and described with respect to the embodiments, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims. | A method for controlling sleep mode of a base station and a mobile station in wireless communication networks, including: determining N of the N-ary exponential sleep mode to decide a length of sleep duration including a sleep interval; measuring downlink traffic addressed to the mobile station at the beginning of a listening interval right after the sleep interval; and when there exist downlink traffic, confirming whether the measured downlink traffic satisfies a mode transition condition. The method further includes: conducting a sleep interval of the next sleep duration of which the length is determined by multiplying the length of the current sleep duration by N unless the downlink traffic satisfies the mode transition condition; and transmitting the downlink traffic to the mobile station when m times the additional consecutive sleep duration is expired or when the measured amount of the downlink traffic satisfies the mode transition condition. | 8 |
BACKGROUND OF THE INVENTION
The present invention relates in general to triggered oscillators and in particular to a triggered oscillator having a frequency locked output signal.
Sampling oscilloscopes were developed more than twenty years ago to observe small, fast-changing signals to which conventional oscilloscopes could not respond due to limited bandwidth or risetime characteristics. Sampling is a now well-known technique wherein a signal path is gated for an extremely short period of time to pass the substantially instantaneous amplitude value (voltage sample) of an electrical signal during that period. Each sample taken in this manner is processed by electronic circuits and displayed as a dot on a cathode-ray tube (CRT) screen at an appropriate position corresponding to the relative timing and magnitude of the sample. Since the samples appear on the CRT display as dots, a large number of samples are required to accurately reconstruct a waveform. Generally speaking, sampling is most practical when the electrical signal is repetitive in nature since it is impossible to acquire all of the needed samples during a single cycle of all but relatively low frequency signals. Indeed, one of the advantages of sampling is that at least one-sample can be acquired from each of a large number of cycles of a high frequency signal, and a representative waveform may be reconstructed and displayed therefrom.
High frequency noise in a waveform can cause a sampling system to distort the waveform display, particularly if a sample happens to be taken at a noise peak. One method of reducing the effects of noise would be to sample a periodic waveform repeatedly at similar times with respect to an event (such as a zero crossing) occurring in repetitive sections of the waveform and then to average the digitized results to determine the actual magnitude of the waveform at each sample time. For instance if 1000 repetitive waveform sections were sampled at similar points, and the sample values were averaged, the effects of noise in any one sample would be reduced by a factor of 1000.
In sequential sampling systems waveforms are sampled at periodic intervals. In order for a sequential sampling system to be used in conjunction with such an averaging method for reducing noise effects, the sampling frequency would have to remain constant and the sample timing with respect to the repetitive event in a sampled waveform would have to remain constant during several repetitive sections of a waveform. However, in sequential sampling systems of the prior art, the point at which sampling begins following a triggering event in the waveform cannot be precisely controlled. Since sample timing is typically controlled by a strobe signal generator which initiates sampling in response to a periodic input signal produced by an oscillator, what is needed is a triggered oscillator for producing a periodic clock signal of precisely controllable frequency in which the first cycle of the periodic signal coincides with a triggering signal derived from a repetitive triggering event in a waveform.
A triggered oscillator of the prior art includes a NOR gate having an output delayed by a delay circuit and then fed back to an input of the NOR gate. An active low trigger signal is applied to a second input of the NOR gate. When the trigger signal is asserted, the output of the NOR gate oscillates with a frequency determined by the delay time associated with the delay circuit, but when the trigger signal is not asserted the NOR gate output does not oscillate. However due to temperature changes, differences in components utilized in the oscillator and other sources of error, the frequency of the triggered oscillator output signal is not accurately predictable and tends to change over time.
SUMMARY OF THE INVENTION
In accordance with one aspect of the invention, a triggered oscillator produces a frequency controlled output signal initiated by an active low triggering signal. The oscillator includes a NOR gate having its output fed back to one of its inputs through a programmable delay circuit while the triggering signal is applied to another of its inputs. When enabled by the triggering signal, the output signal of the NOR gate oscillates at a frequency inversely proportional to the delay time of the delay circuit. The delay time is programmed by a control circuit which continuously measures the frequency of the NOR gate output signal and increments the delay time if the frequency is too high and decrements the delay time if the frequency is too low, thereby to correct the frequency of the oscillator output.
In accordance with another aspect of the invention, the frequency of the NOR gate output signal is measured by counting the NOR gate output signal cycles during a measurement time interval which is in turn measured by counting cycles of a reference clock signal of known frequency. If the count of the NOR gate output signal cycles during the measurement time interval is higher than an expected value, the output signal frequency is too high and the delay time is increased by an amount proportional to the excess cycle count. Conversely, if the count of the NOR gate output signal cycles is lower than the expected value, the output signal frequency is too low and the delay time is decreased by an amount proportional to the cycle count deficiency. Thus the oscillator output signal is frequency locked to the reference clock signal while being phase locked to the trigger signal. The frequency of the output signal can be easily changed by modifying the magnitude of the expected count value.
In accordance with a further aspect of the invention, the triggered oscillator is adapted to respond to a repetitive triggering signal by rephasing its output signal to the triggering signal upon each receipt of the triggering signal and to perform frequency locking utilizing either of two frequency locking modes depending on the repetition rate of the triggering signal. When the period between triggering signals is longer than the frequency measurement time interval, the oscillator may be operated in a "continuous" count mode wherein the oscillator continuously repeats the frequency count and correction operation but terminates and restarts a current output frequency measurement each time the triggering signal is stopped and restarted. The continuous count mode ensures that the output signal frequency will be continuously corrected between triggering signals to avoid drift. When the period between triggering signals is shorter than the measurement time interval, the oscillator may be operated in a "processor start" mode wherein a frequency count is initiated only on command of a controlling microprocessor and continues for the full duration of the measurement time interval irrespective of any stopping and restarting of the triggering signal during the measurement time interval. The processor start mode ensures that the frequency count will be completed so that the output signal frequency can be adjusted.
It is accordingly an object of the invention to provide a new and improved oscillator for producing a periodic output signal of controllable frequency which is phase locked to a trigger signal.
The subject matter of the present invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. However, both the organization and method of operation, together with further advantages and objects thereof, may best be understood by reference to the following description taken in connection with accompanying drawings wherein like reference characters refer to like elements.
DRAWINGS
FIG. 1 is a simplified block diagram of the present invention;
FIG. 2 is a more detailed block diagram of the present invention;
FIG. 3 is a state diagram for the state machine of FIG. 2; and
FIG. 4 is a flow chart for a program for controlling the operation of the microprocessor of FIG. 2.
DETAILED DESCRIPTION
Referring to FIG. 1, there is depicted in simplified block diagram form a triggered, frequency locked oscillator 10 according to the present invention adapted to generate a periodic output signal Vo of controlled frequency commencing on receipt of a trigger signal YTRIG. The trigger signal is applied as an input to a NOR gate 12 which produces the oscillator output signal Vo as its output. The output signal Vo is fed back as voltage Vo' to another input of the NOR gate through a delay circuit 14 delaying the Vo signal by a programmably determined delay time Td. When the YTRIG signal is held continuously high, the output of the NOR gate Vo stays continuously low and therefore the oscillator 10 output is inhibited. When the YTRIG signal goes low the NOR gate 12 output Vo immediately goes high, and after delay time Td the input voltage Vo' to NOR gate 12 goes high. At this point the output Vo of NOR gate 12 is driven low again and after another delay time interval Td, Vo' goes low again. This process continues indefinitely as long as the YTRIG signal remains low, with Vo oscillating at a frequency determined by Td. When the YTRIG signal goes high again, Vo is driven low and remains low as long as the YTRIG signal stays high.
Thus NOR gate 12 cooperates with delay circuit 14 to produce an output signal Vo of frequency determined by the delay time Td of the delay circuit. The output signal commences when the YTRIG signal is driven low and stops when the YTRIG signal is driven high again. The frequency of the output signal can be controlled by controlling the delay time Td.
To ensure that the delay time Td is properly adjusted so that the oscillator 10 produces an output signal Vo of the desired frequency, the frequency of the output signal Vo is measured, and if the frequency is too high or too low, the delay time Td is increased or decreased accordingly. The frequency of the oscillator output signal Vo is measured by a counter 16, the oscillator output signal Vo being applied to a clock input of counter 16 while a signal HSTOP of is applied to a gate input (S) of counter 16. The counter 16 counts pulses of the oscillator output signal Vo occurring while the HSTOP at its gate input is low and stops counting when HSTOP is driven high. The count is reset to zero by a signal IHZERO applied to a reset input of the counter.
After the count of counter 16 is reset to zero by IHZERO signal, the HSTOP signal is driven low for a known period T. The count C generated by counter 16 at the end of period T represents the number of cycles of the oscillator output signal Vo occurring during period T and this number will equal a known constant M if the Vo signal is of the appropriate frequency. For instance if the frequency of Vo is to be 100 MHz, and if the duration of period T is 100 microseconds, then the constant M will be 10,000. If C is less than 10,000, the frequency of Vo is too low. If C is greater than 10,000, the frequency of Vo is too high. The output C of counter 16 is provided as input to a microprocessor 18 which subtracts the value of C from the constant M to produce a difference variable Cd. In FIG. 1, the subtraction operation is represented by symbol 20. The difference variable Cd is then scaled by multiplying Cd (operation 22) by a scaling factor X to produce a scaled difference value Cd' which is then added to another variable Cp (operation 24). The result of operation 24 replaces the previous value of variable Cp. An HDATARDY signal, applied as input to the microprocessor 18, is asserted at the end of each counting period T to indicate that the counter 16 has completed its count, and this signal causes the microprocessor to read the value of C from counter 16 and to perform operations 20, 22 and 24 and to store and output the new value of Cp. The operation of storing and outputting Cp, which is actually carried out by software, is represented in FIG. 1 by a register 26 receiving the output of operation 24 as input and producing the Cp variable as output. The microprocessor 18 transmits the Cp variable to a latch 28 clocked by a system clock (SYSCLK) signal and, when Cp is latched into latch 28, Cp is transmitted to a digital to analog converter (DAC) 30 which converts Cp into an analog signal Vp of proportional magnitude. The Vp signal controls the delay time Td of programmable delay circuit 14, where Td is inversely proportional to Vp.
By inspection of FIG. 1 it can be seen that if the frequency of Vo is too large, the count C output of counter 16 at the end of counting period T will be greater than M. Thus Cd' will be negative (X being a positive number). On assertion of the HDATARDY signal, the magnitude of Cp will be reduced by the value of Cd' and when the new value of Cp is latched into latch 28, the magnitude of Vp will be reduced. This causes an increase in Td which in turn causes a corrective decrease in the frequency of Vo. Conversely, if the frequency of Vo is too small, the count C at the end of period T will be less than M, and Cd' will be positive. Thus the value of Cp will be increased, causing an increase in the magnitude of Vp, a decrease in Td, and ultimately a corrective increase in the frequency of Vo.
Once the duration of counting period T is chosen, and the desired frequency of Vo is selected, the only variable which is not fixed is the scaling factor X. The magnitude of X is chosen to be large enough to provide fast frequency correction response without being so large that frequency is overcorrected, leading to instability. Since the frequency of the output signal Vo can change after each frequency measurement and correction cycle, the frequency of output signal Vo can be expressed as a function of the measurement cycle:
F(n)=1/[Td(n)+Tc] [1]
where n denotes the nth measurement and correction cycle since the YTRIG signal triggered the oscillator output, F(n) denotes the frequency of Vo following the end of the nth frequency measurement and correction cycle, Td(n) represents the time delay setting of delay circuit 14 after the nth cycle, and Tc is an inherent time delay associated with NOR gate 12. Normally Tc is very small compared to Td(n) and can be ignored. Therefore equation [1] reduces to
F(n)=1/Td(n). [2]
The time delay Td(n) is inversely proportional to the value of Vp(n), according to some fixed constant of proportionality m' (determined by the characteristics of the delay circuit 14) such that
1/Td=m'Vp(n). [3]
Substituting equation [3] into equation [2],
F(n)=m'Vp(n). [4]
But Vp(n) is proportional to Cp(n) by another fixed constant of proportionality j determined by the characteristics of the DAC 30. Therefore from equation [4]
F(n)=mCp(n) [5]
where m=jm'. From equation [5] it follows that the frequency of Vo after the next frequency measurement and correction cycle (n+1) will be
F(n+1)=mCp(n+1). [6]
The value of Cp(n+1) is related to the value of Cp at the end of the previous frequency correction cycle n. Specifically,
Cp(n+1)=Cp(n)+Cd'(n). [7]
Therefore, ##EQU1## But from equation [5] mCp(n) is equal to F(n). Thus
F(n+1)=F(n)+mX[M-C(n)]. [9]
From FIG. 1, the count output C(n) of counter 16 at the end of period n is equal to product of the duration of the count T and the frequency F(n) of the Vo signal. Thus it follows that ##EQU2##
This equation has a solution for F(n) as follows:
F(n)=[F(O)-M/T][1-mXT].sup.n +M/T [11]
where F(O) is the initial frequency of Vo prior to the start of the first frequency measurement and correction cycle. From equation 11 it is noted that the product mXT should be greater than 0 and less than 2 if F(n) is to remain stable; otherwise the absolute value of the term [1-mXT] n will grow increasingly larger after each frequency correction cycle, causing F(n) to be unstable. Since the values of m and T are fixed by the physical constraints of the oscillator circuit components and by the desired frequency, an appropriate value of X may be chosen such that 0<mXT<2, with an ideal value of mXT=1, so that the frequency of the oscillator output signal is rapidly corrected and does not become unstable.
The oscillator 10 of FIG. 1, depicted in more detailed block diagram form in FIG. 2, includes in addition to XOR gate 12, delay circuit 14, counter 16, microprocessor 18, latch 28 and DAC 30, other components for controlling the operation of the oscillator 10 depicted in FIG. 1. The sequence of frequency measurement operations of the oscillator is controlled by a state machine 34. The duration of the HSTOP signal applied to the gate input S of counter 16 is controlled by a count down timer 32 which stores count limit data (DATA) on assertion of an LLOAD signal from the state machine 34 and counts down from the stored count limit on receipt of each pulse of the system clock SYSCLK after the LLOAD signal is deasserted. When the count reaches zero, the timer 32 transmits an output signal pulse (TIMEUP) back to the state machine 34 and to an OR gate 36 having inverting and non-inverting outputs connected to the K and J inputs, respectively, of a JK flip-flop 38. An HHold signal from the state machine 34 is applied to another input to the OR gate 36. JK flip-flop 38 is clocked by the Vo output of NOR gate 12 and is reset by an externally generated IHSYSRESET signal. The Q output of flip-flop 38 comprises the HSTOP signal controlling the count enabling input S of counter 16. State machine 34 generates the IHZERO signal which controls the reset input of counter 16.
Prior to a frequency measurement operation, the state machine 34 asserts the HHOLD signal (active high) causing OR gate 36 to drive the J input of flip-flop 38 high and the K input low, thereby setting the flip-flop such that its Q output (HSTOP) stays high. When the HSTOP is high counter 16 does not count. At the same time, the state machine 34 also asserts the IHZERO signal which resets the counter 16 and asserts the LLOAD signal to load the limit data into the timer 32. To initiate a frequency measurement operation, the state machine deasserts the HHOLD signal at the same time it deasserts the LLOAD signal. Deassertion of the HHOLD signal causes flip-flop 38 to reset, driving the HSTOP output low to enable counter 16 to begin a frequency count, while deassertion of the LLOAD signal causes the timer 32 to begin its count down. The count limit data is sized so that timer 32 produces the HTIMEUP signal after an interval of duration T, the period of the frequency count. For instance if the system clock SYSCLK is 50 MHz, and a count interval T of 100 microseconds is desired, then the count limit is set to 5,000 so that timer 32 will produce the HTIMEUP signal 100 microseconds after receiving the LLOAD signal.
When the timer 32 asserts the HTIMEUP signal, the OR gate 36 sets flip-flop 38, driving HSTOP high to stop the frequency count operation of counter 16. At the same time, when state machine 34 detects the assertion of the HTIMEUP signal, it reasserts the HHOLD signal to inhibit counter 16 from resuming the count once HTIMEUP goes low again. After detecting the HTIMEUP signal, state machine 34 asserts the HDATARDY signal causing microprocessor 18 to read and process the count data output C of counter 16 in the manner previously described to produce a new value of control data Cp which is transmitted to latch 28. On the next subsequent SYSCLK pulse, this value of Cp passes through latch 28 to DAC 30 which produces a new value for Vp to appropriately correct the delay time of delay circuit 14.
In addition to processing the count data and producing Cp, the microprocessor 18 also initiates frequency measurement and correction cycles by transmitting a YGOSTROBE signal to a clock input of a type D flip-flop 46. The D input of flip-flop 46 is tied to a logical "1" source so that the Q output of the flip-flop is driven high when the YGOSTROBE signal is asserted. The Q output of flip-flop 46 is an input signal YGO to the state machine 34 which tells the state machine to initiate a frequency measurement and correction cycle. After the state machine 34 receives the YGO signal it resets the flip-flop 46 by transmitting an IHRSTYGO signal to an input of an OR gate 48, the output of which drives the reset input of the flip-flop.
The oscillator 10 of the present invention is adapted to operate in either of two frequency correction modes. In a "continuous run" mode, the microprocessor 18 initiates a frequency measurement and correction cycle following receipt of an externally generated START signal (which may be derived from the YTRIG signal) and reinitiates a new frequency measurement and correction cycle continuously thereafter each time such a cycle completes so that the frequency of Vo is continuously corrected. The oscillator 10 may also be operated in a "processor start" mode wherein only one frequency measurement and correction operation is performed following assertion of the START signal and the microprocessor does not reset counter 16 until it detects another START signal. The desired mode of operation (continuous run or processor start) is provided as externally generated input data MODE to the microprocessor 18 prior to operation of the oscillator 10. The microprocessor transmits a YCONMODE signal to the state machine 34 which remains high if the oscillator is to operate in the continuous run mode and low if the oscillator is to operate in the processor start mode. The state machine monitors the YCONMODE signal to determine the current mode of oscillator operation.
The continuous run mode is appropriate when the YTRIG signal is not stopped and restarted very often compared to the duration T of the frequency count period. Since the YTRIG signal may be briefly stopped and reasserted while counter 16 is counting, the count will misrepresent the actual frequency of the Vo signal. Therefore, in the continuous run mode, the state machine 34 stops, resets and restarts the frequency count whenever the YTRIG signal is stopped and restarted. Since the operation of the state machine 34 is clocked by the system clock signal SYSCLK, a pair of type D flip-flops 40 and 42 are provided to synchronize YTRIG signal to the system clock and to provide an indication as to when the YTRIG signal has been stopped and restarted. The YTRIG signal clocks flip-flop 40 having its D input tied to a logic "1" so that it sets when the YTRIG signal is asserted (driven low). The Q output of flip-flop 40 drives the D input of flip-flop 42 which is clocked by SYSCLK. Thus flip-flop 42 sets on the trailing edge of the first SYSCLK pulse following the YTRIG signal. The Q output of flip-flop 42 is applied as an input to state machine 34 as a synchronized "trigger restart" indicating signal YRST. If the state machine detects the YRST signal during a frequency count operation while the oscillator is operating in the continuous run mode, it knows that the YTRIG signal has been stopped and restarted and, accordingly, the state machine stops and restarts the frequency count by asserting and deasserting the IHZERO and the LLOAD signals. The IHZERO signal also resets flip-flop 40 to prepare the flip-flop to detect when the YTRIG signal is stopped and asserted again.
As previously mentioned, when the state machine 34 detects the HTIMEUP signal, indicating that the frequency measurement period is complete, it transmits the HDATARDY signal to the microprocessor 18, telling it to read and process the count data output C of counter 16. However the microprocessor requires a certain amount of time to process the count data C to produce a new value for Cp and an additional amount of time is required for the new Cp data to effectuate a change in the frequency of Vo due to delays in latch 28 and DAC 30. Therefore the state machine 34 must not restart another frequency measurement operation until the microcomputer 18 has had time to process the count data and to adjust the frequency of Vo. Accordingly when the oscillator is operating in the continuous run mode, the microprocessor 18 delays assertion of the YGOSTROBE signal for the appropriate amount of time following detection of the HDATARDY signal so that the state machine 34 does not restart the frequency count until after the frequency of Vo has been adjusted. When the oscillator 10 is in the continuous run mode, the state machine 34 checks for the assertion of an externally generated YDELAYEDTRIG signal before initiating another count measurement cycle. The YDELAYEDTRIG signal is produced by delaying the YTRIG signal briefly in order to ensure that the frequency count cycle does not start immediately after a YTRIG signal has been asserted since it takes a moment for the frequency of the oscillator output signal Vo to stabilize following assertion of YTRIG signal.
The continuous run mode of oscillator operation is not appropriate when the YTRIG signal is stopped and reasserted so often that the counter 16 cannot complete a frequency count since in such case the oscillator output signal frequency cannot be adjusted. Therefore the oscillator is operated in the processor start mode when YTRIG is frequently stopped and restarted. In this mode, the microprocessor 18 generates a YGOSTROBE signal only once after each assertion of the START signal to initiate a single frequency measurement and correction cycle. While the state machine 34 initiates a frequency measurement count after receipt of the YGO signal from the microprocessor, it ignores the YRST signal so that the frequency measurement count is completed even if the YTRIG signal happens to be deasserted and reasserted during the frequency count. The count completion mode is inappropriate when the YTRIG (and subsequent therefore START) signal assertions are widely separated in time because only one frequency measurement and correction operation is performed after each START signal assertion and the frequency of Vo may drift considerably before the START signal is reasserted.
The operation of the oscillator 10 may be reset to an initial state at any time by an externally controlled reset signal, IHSYSRESET. This signal provides an input to the state machine 34 and causes the state machine to reset to an initial state wherein it resets the frequency count of counter 16 and waits for a new YGO signal before initiating another count. The IHSYSRESET signal is also applied to the reset input of flip-flop 38, causing the flip-flop to drive the HSTOP signal high, which stops the count of counter 16, and to an input of OR gate 48, causing the OR gate output to reset flip-flop 46 to drive the YGO signal low.
FIG. 3 is a diagram for the operation of the state machine 34 of FIG. 2. On system power up or reset (IHSYSRESET) the state machine enters a state Y (block 50) wherein the state machine asserts its HDATARDY and HHOLD signals. The HHOLD signal prevents counter 16 of FIG. 2 from counting. The state machine 34 waits (block 52) for the YGO signal from the microprocessor via flip-flop 46 and then enters state Z (block 54). In state Z the state machine asserts the LLOAD, IHZERO, and HHOLD signals to load data into the timer 32, to reset the counter 16, and to inhibit counter operation. If the oscillator is operating in the continuous run mode (tested in block 55), the state machine remains in state Z until it detects the YDELAYEDTRIG signal (block 57). If the state machine detects the YDELAYEDTRIG signal, or is in the processor start mode, then the state machine enters state W (block 56) on the next system clock cycle. In state W the LLOAD, IHZERO, and HHOLD signals are all deasserted, causing the counter 16 to begin counting Vo cycles and the timer 32 to begin its count down. The state machine also asserts the IHSTYGO signal while in state W to reset flip-flop 46. If the oscillator is in the processor start mode, or if the oscillator is in the continuous run mode and the YRST signal has not been asserted (conditions tested in block 58), the state machine remains in state W until it detects the HTIMEUP signal (block 60) indicating the end of the frequency measurement interval, at which point the state machine enters state X (block 62). However if the oscillator is in the continuous run mode, and the state machine is in state W waiting for assertion of the HTIMEUP signal, but detects that the YRST signal has been asserted before the HTIMEUP signal is asserted, then the state machine moves directly (via block 58) to state X without waiting for the HTIMEUP signal.
In state X the state machine reasserts the HHOLD signal to stop the frequency count and reasserts the IHRSTYGO signal to reset the YGO signal output of flip-flop 46. On the next system clock cycle the state machine checks the YRST and YCONMODE signals again (block 64), and if the YRST signal has not been asserted, or if the oscillator is in the processor start mode, the state machine returns to state Y (block 50) where it asserts the HDATARDY and HHOLD signals and waits for reassertion of the YGO signal to start another measurement cycle. However if the oscillator is in the continuous run mode, and the trigger signal has been stopped and restarted, then the YRST signal will be asserted, and the state machine will change from state X to state Z via block 64, by-passing state Y such that another measurement cycle is initiated without waiting for the YGO signal from the microprocessor.
FIG. 4 is a flow chart for programming the microprocessor 18 of FIG. 2 for oscillator operation in the continuous run mode. On detection of the START signal in step 66 the processor asserts the YGOSTROBE signal in step 68 to initiate a frequency count and then waits (step 70) until the state machine asserts the HDATARDY signal, indicating that the frequency count is complete. At that time the microprocessor reads the frequency count data C (step 72), computes the value of Cd from the stored values of M and C (step 74), computes the new value of Cp by adding the previous value of Cp to the product of the stored value of X and the computed value of Cd (step 76) and then outputs the new value of Cp to latch 28 of FIG. 2 (step 78). The microprocessor waits (step 80) for a time sufficient for the new value of Cp to change the frequency of the oscillator output signal Vo, and returns to step 68 where it reasserts the YGOSTROBE signal to initiate another measurement cycle. When the oscillator is operating in the processor start mode, the microprocessor is programmed to operate in a similar fashion to that depicted in FIG. 4 except that the flow of operation terminates after step 78 and is not returned to step 68 so that a frequency measurement and correction cycle is initiated only once following the START signal.
Thus the oscillator of the present invention is adapted to produce a periodic output signal commencing on receipt of a trigger signal and to monitor and control the frequency of the output signal. The oscillator is particularly suited for controlling the timing of sampling in a waveform sampling and digitizing system. When the triggering signal for the oscillator is derived from a repetitive triggering event in a periodic waveform being sampled, the waveform can be sampled repetitively at the same times relative to a repetitive triggering event in the waveform because samples will be taken at the same regular intervals following each triggering event. This allows sample data taken at similar times along successive, repetitive waveform sections to be averaged, thereby reducing the effects of transients in the waveform on characterizations of the waveform magnitude based on sample data.
While a preferred embodiment of the present invention has been shown and described, it will be apparent to those skilled in the art that many changes and modifications may be made without departing from the invention in its broader aspects. The appended claims are therefore intended to cover all such changes and modifications as fall within the true spirit and scope of the invention. | An oscillator produces an output signal which is frequency locked to a reference signal but phased locked to a triggering signal. The oscillator includes a NOR gate having its output fed back to one of its inputs through a programmable delay circuit while the triggering signal is applied to another of its inputs. When enabled by the triggering signal, the output signal of the NOR gate oscillates at a frequency inversely proportional to the delay time of the delay circuit. The delay time is controlled by a control circuit which counts NOR gate output signal cycles occurring during a predetermined number of reference signal cycles and increments the delay time when the count is higher than expected for an oscillator output signal of a desired frequency and decrements the delay time when the count is lower than expected. | 8 |
FIELD OF INVENTION
[0001] The present invention relates to methods of production of the completely post-translationally modified protein by combination of cell-free protein synthesis and cell-free complete post-translational modification.
BACKGROUND
[0002] The present invention relates to protein production of therapeutic, research and commercial value requiring post-translational modification not by a cell culture method but a cell-free completely post-translationally modified protein synthesis method. To explain in more detail, using a cell-free completely post-translationally modified protein synthesis method comprised of cell extract including protein synthesis machinery and cell membrane extract including complete post-translational modification machinery, a valuable protein is produced.
[0003] Many pharmacological proteins undergo post-translational modifications such as glycosylation, phosphorylation and amidation etc. that are indispensable for their activity. Moreover, the majority of proteins secreted by mammalian cells are post-translationally modified. Many proteins become post-translationally modified during the ‘secretory process’, which comprises of a journey from their site of synthesis in the rough endoplasmic reticulum (ER), through the Golgi apparatus and then to various cellular or extracellular destinations. In post-translational modification of a protein, inorganic phosphate is attached to proteins through phosphorylation, amide group is generated at the terminus of polypeptides by amidation and carbohydrate is attached to proteins through glycosylation. Of these, the most complex procedure involving several enzymes is glycosylation. Hence, glycoproteins are the most diverse group of biological compounds that are ubiquitous constituents of almost all living organisms. They occur in cells in both soluble and membrane-bound forms as well as in the extracellular matrix and in intercellular fluids, and they serve a variety of functions. These proteins possess oligosaccharides covalently attached through an asparagine (Asn) side chain (“asparagine-linked” or “N-linked”) or through a threonine or serine side chain (“O-linked”). A given glycoprotein may contain N-linked oligosaccharide chains only, O-linked oligosaccharide chains only, or both. The carbohydrate units of glycoproteins exhibit considerable variation in size and structure ranging from mono- or disaccharide to a branched oligosaccharide composed of as many as 20 monosaccharide residues.
[0004] In summary, N-linked glycosylation begins with the synthesis of a lipid-linked oligosaccharide moiety, and its transfer en bloc to a nascent polypeptide chain in the ER. Attachment occurs through Asn, generally at the tripeptide recognition sequence Asn-X-Ser/The, where X can be any amino acid from naturally occurring amino acids. A series of trimming reaction is catalyzed by exoglycosidase in the ER. Further processing of N-linked oligosaccharides by mammalian cells continues in the compartment of the Golgi, where a sequence of exoglycosidase- and glycosyltransferase-catalyzed reactions generate high-mannose, hybrid-type and complex-type oligosaccharide structures.
[0005] For the biosynthesis of post-translationally modified proteins with biological activity, it is necessary to culture eukaryotic cells capable of undergoing the post-translational modification including glycosylation. The production of post-translationally modified proteins by the culture of such cells, however, costs a great deal, e.g., in right of culture medium cost, operation cost, apparatus cost, etc. This process is also very time-consuming and in order to simplify the process and to save time, many cell-free protein synthesis systems have been developed.
[0006] A cell-free protein synthesis has been used as an experimental tool for the investigation of gene expression in vitro especially for the proteins that cannot be synthesized in vivo because of their toxicity to host cells. In addition, various synthetic amino acids besides the 20 natural amino acids can be effectively introduced by this method into protein structures for specially designed purposes (Noren, C. J. et al., Science 244:182-188 (1989)). Moreover, the cell-free protein synthesis has been recently re-evaluated as an alternative to the production of commercially important recombinant proteins, which is mainly due to the recent development of a novel reactor system and the extensive optimization of reactor operating conditions (Kim, D. M. et al., Eur. J. Biochem. 239:881-886 (1996); Kigawa, T. et al., FEBS Lett. 442:15-19 (1999)). Therefore, the development of cell-free protein synthesis systems has reached the next stage, i.e., the production of active proteins on a commercial scale.
[0007] Accordingly, some methods were developed to produce the co-translationally modified and the initial post-translationally modified proteins by adding organelles relevant to the co-translational and the initial post-translational modification to these cell-free protein synthesis systems. As a representative method, U.S. Pat. No. 6,103,489 discloses that cell-free assay systems for proteins with the co-translational and the initial post-translational modification have been constructed by combining a eukaryotic cell-free translation system with rough microsome. In another method, the extract including translational components and post-translational modification components such as ER was prepared by a single step extraction from a single source (Hiroshi, T., et al., J. Biosci. Bioeng. 5:508-514 (2000)). In cells, the biosynthesis of many proteins requires. co-translational translocation across membranes of an organelle called ER for proper processing. In cell-free systems, in place of the ER, microsomal membranes are used, which are equivalent to the ER in that they contain a high percentage of ER membrane which have been isolated by centrifugation. These reconstituted assay systems for assessing protein translation and the initial post-translational processing in higher eukaryotes have allowed characterization of the translocational machinery, and are being actively used to define the topology of membrane proteins and to elucidate the regulation of N-linked core glycosylation. However, they do not produce the completely post-translationally modified proteins. Since proteins not completely post-translationally modified do not have the complete and correct structure, they cannot be used to study the utility and characteristics of proteins including pharmacological activities. This is due to the fact that proteins with incomplete post-translational modification or no post-translational modification do not or have low biological activity and therefore cannot be used therapeutically. Current cell-free protein synthesis methods cannot produce proteins with a complete structure and therefore is insufficient to be used to study post-translational modifications or functions of genes.
[0008] In the meantime, from the results of the Human Genome Project, a great deal of information on the genetics of human have been obtained. In the near future, the complete genome map of humans being will be available. At present, we have reached the Post Genomic Era where the functions of genes and their encoded proteins are being studied. In order to achieve this goal, computer programs that can use information about the sequence of a gene to predict the structure of the encoded protein are used in bioinformatics. From the predicted structure of the protein and the sequence of the gene, the function of the protein can be elucidated. This process of obtaining the function of the protein through prediction is not a completely satisfactory method. A better method would be to express the protein and to study the function through experiments. The protein to be studied should have the complete co- and post-translational modifications. To produce these proteins, the genes of interest should be expressed in a eukaryotic host cell. This process is very time-consuming and in order to simplify the process and to save time, cell-free protein synthesis can be used. Up until now, a cell-free protein synthesis system with a complete post-translational modification has not been developed. Therefore, a cell-free protein synthesis system capable of producing a protein that has undergone complete post-translational modifications needs to be developed.
[0009] To solve the problem of prior art that cell-free protein synthesis systems produced incompletely post-translationally modified protein, the present invention provides methods of producing the completely post-translationally modified proteins by a more advanced cell-free protein synthesis system, in particular, by the combination of cell-free protein synthesis and cell-free complete post-translational modification.
[0010] We expect that the methods of cell-free protein synthesis according to the present invention can become a useful tool for synthesizing completely post-translationally modified protein for the functional analysis of proteins and the large-scale production of therapeutically important proteins, and to serve as a model system for elucidating the role of proteins and the mechanisms of post-translational modification.
SUMMARY OF THE INVENTION
[0011] In order to achieve such goal, the present invention provides a method for preparing completely post-translationally modified protein via coupled cell-free completely post-translationally modified protein synthesis comprising;
[0012] adding a DNA template to a cell extract,
[0013] adding ribonucleotide triphosphates to the extract, and
[0014] adding a sufficient amount of co- and post-translational modification machinery such as ER/Golgi apparatus, or ER/Golgi apparatus/plasma membrane, or other organelles in addition to these to the extract to stimulate the production of completely post-translationally modified protein,
[0015] or via uncoupled cell-free completely post-translationally modified protein synthesis comprising;
[0016] adding a RNA template to a cell extract, and
[0017] adding a sufficient amount of co- and post-translational modification machinery such as ER/Golgi apparatus, or ER/Golgi apparatus/plasma membrane, or other organelles in addition to these to the extract to stimulate the production of completely post-translationally modified protein.
[0018] The most complex post-translational modification process requiring several enzymes is glycosylation. Correct glycosylation implies that most post-translational modification is possible using the same method.
[0019] Reviewing the glycosylation process of proteins in cells, glycosylation in most eukaryotes occurs commonly in the ER, i.e., yeast, insect, plant and mammalian cells share the features of N-linked oligosaccharide processing in the ER. Though the resultant glycoproteins in the ER have a near identical carbohydrate structure, with only the initial glycosylation in the ER, glycoproteins with a therapeutic efficacy cannot be fully produced.
[0020] The production of premature glycoprotein, which does not undergo the complete post-translational modification, may be caused by the deficiency of the terminal glycosylation machinery such as the Golgi apparatus. In other words, oligosaccharide processing by different cell types may diverge in the Golgi apparatus. The initial step in O-glycosylation by mammalian cells is the covalent attachment of N-acetylgalactosamine to serine or threonine. No O-glycosylation sequence has been identified analogous to the Asn-X-Ser/Thr template required for N-glycosylation. In further contrast to N-glycosylation, no preformed, lipid-coupled oligosaccharide precursor is involved in the initiation of mammalian O-glycosylation. Sugar nucleotides serve as the substrates for the first and all subsequent steps in O-linked processing. Following the covalent attachment of N-acetylgalactosamine to serine or threonine, several different processing pathways are possible for mammalian O-linked oligosaccharides in the Golgi. The oligosaccharide structures of glycoproteins can have a profound effect on properties critical to the human therapeutic use, including plasma clearance rate, antigenicity, immunogenicity, specific activity, solubility, resistance to thermal inactivation, and resistance to protease attack. Therefore, for a cell-free protein synthesis to be applied to the large-scale production of glycoprotein and for a rapid insight into the role of protein glycosylation to understand the relationship among. stability, conformation, function of protein and glycosylation, an efficient cell-free completely post-translationally modified protein synthesis system in which protein is completely post-translationally modified needs to be developed.
[0021] For the production of proteins having the complete and correct structure, the present invention includes the combination of a cell-free protein synthesis system and co- and post-translational modification machinery containing organelles, separated from cells, relevant to co- and post-translational modification. This cell-free completely post-translationally modified protein synthesis method is a new approach that has not been attempted by anyone. This method is suitable especially to large-scale production of efficacious and useful proteins. Additionally, this method can be applied directly to post-translational modification processes, required to produce a biologically active protein besides glycosylation.
BRIEF DESCRIPTION OF DRAWINGS
[0022] FIG. 1 shows an autoradiogram of completely post-translationally modified EPO by the method disclosed in the present invention and unmodified EPO that have been separated by SDS-polyacrylamide gel electrophoresis;
[0023] FIG. 2 shows the result of western blotting of EPO produced by a conventional cell culture method and by the present invention.
[0024] FIG. 3 shows an autoradiogram of EPO treated with glycosidase.
[0025] FIG. 4 shows an autoradiogram of EPO produced by an uncoupled cell-free completely post-translationally modified protein, synthesis and by a coupled cell-free completely post-translationally modified protein synthesis.
DETAILED DESCRIPTION OF THE INVENTION
[0026] Because of the inability of prokaryotes to modify proteins co- or post-translationally, the cell-free protein synthesis system used in the present invention must be derived from eukaryotes. Up to now, several sources of eukaryotic lysate (protein-synthesizing machinery) including fungi, mammalian cells (e.g., reticulocytes, endothelial cells, and lymphocytes), immortalized cell lines (e.g., cancer cell lines, etc.), plant cells (such as wheat germ or embryo cells, etc.) were used. And an efficient eukaryotic coupled cell-free transcription and translation system was developed using bacteriophage RNA polymerase and rabbit reticulocyte lysate (RRL) (U.S. Pat. No. 5,324,637). The terms “coupled transcription/translation system” and “coupled cell-free protein synthesis system” define the process whereby transcription and translation steps are carried out in sequence in a cell-free system. The terms “uncoupled cell-free protein synthesis system” and “cell-free translation system” apply to the process where the transcribed mRNA is purified after the initial transcription step and then the purified mRNA is transferred to a separate reaction system in which protein synthesis takes place.
[0027] As mentioned above, since the addition of only the ER cannot produce the completely post-translationally modified proteins, the addition of co- and post-translational modification machinery involved in terminal glycosylation is necessary. The addition of co- and post-translational modification machinery containing signal recognition particle, ER, Golgi apparatus, plasma membrane, and the like to the cell-free protein synthesis reaction mixture stimulates the production of completely post-translationally modified protein. A complete incubation mixture (containing the components of cell-free protein synthesis and co- and post-translational modification machinery) gives the completely post-translationally modified proteins. The events of the co- and post-translational modification process could be faithfully reproduced in vitro. The results described in the present invention have opened the possibility of a cell-free protein synthesis as an alternative to the in vivo production of pharmacological proteins and increased the understanding of the co- and post-translational modification process.
[0028] Cell sources for the preparation of the extract or lysate for the cell-free protein synthesis system and those for the co- and post-translational modification machinery may be the same or different. In the case of using the same cell, the extract or lysate for the cell-free protein synthesis system and the co- and post-translational modification machinery may be prepared separately or together.
[0029] The co- and post-translational modification machinery may be prepared from tissues and cultured cell lines. In glycosylation it is favorable to genetically engineer a cell source for the enhancement of the expression level of glycosylation related enzymes and/or for the enrichment of the pool of sugar nucleotides which serve as sugar donors in glycosylation. This type of genetic manipulation can be carried out by those skilled in the art; therefore, the detailed explanation is omitted in this specification.
[0030] As an example for obtaining the cell extract in the cell-free protein synthesis method, the preparation of nuclease-treated RRL and a crude homogenate from Chinese hamster ovary (CHO) cells are described in detail in Example 1 and 2, respectively. And the preparations of ER containing signal recognition particle, Golgi apparatus, and plasma membrane from a crude homogenate are described in detail in Example 3, 4, and 5, respectively.
[0031] In case of need, the glycoprotein produced by the cell-free protein synthesis method according to the present invention may be further modified through carbohydrate-adding reaction and/or carbohydrate-deleting reaction and/or carbohydrate-substituting reaction with enzymes relevant to the modification of side chains, e.g., glycosyltransferase, glycosidase, transglycosidase and so on. That means the addition, deletion, or substitution of carbohydrate side chains is possible. Furthermore, it is possible to introduce carbohydrate side chains not known in the general glycoprotein structures or to synthesize novel glycoprotein structures artificially, and thus the development of new glycoprotein is anticipated. For example, in the carbohydrate-adding reaction resultant itself or the erythropoietin (EPO) separated from it, sialic acid is further attached to the terminal chain thereof by transglycosidase which is one of carbohydrate chain addition enzymes, and the efficacy of glycoprotein increases with the addition of sialic acid to the terminal chain thereof.
[0032] The present invention can be applied to the production of proteins of therapeutic, commercial or research value. This includes proteins such as growth hormones, granulocyte colony stimulating factor, interleukin, interferon, thrombopoietin, tissue plasminogen activator and humanized monoclonal antibody. Additionally, the present invention not only produces the completely post-translationally modified protein but also can be used as a research tool in the form of a co- and post-translational modification kit in order to discover the function of a gene.
[0033] In one embodiment of the present invention, EPO was produced by cell-free completely post-translationally modified protein synthesis. However, it will be understood that the present invention is not limited to these specific examples, but is susceptible to various modifications that will be recognized by the skilled person in the present invention. Only an example of EPO glycosylation is disclosed but it is representative of all the different co- and post-translational modification. Therefore, the present invention includes all kinds of co- and post-translational modification.
[0034] EPO is a therapeutic glycoprotein currently used to treat anemia associated with several causes including chronic renal failure. EPO is a prime regulator of red blood cell production in mammals and birds. Specifically, this glycoprotein hormone promotes the rapid growth of red blood cell progenitors in marrow, spleen, and fetal liver, and subsequently is required for their terminal differentiation to circulating erythrocytes. Current therapeutic EPO is produced by animal cell culture.
[0035] The production of EPO via coupled cell-free completely post-translationally modified protein synthesis is described in detail in Example 6. And the production of EPO via uncoupled cell-free completely post-translationally modified protein synthesis is described in detail in Example 7. The production of EPO via combination of cell-free completely post-translationally modified protein synthesis and enzymatic in vitro glycosylation is described in detail in Example 8.
[0036] The present invention will now be illustrated by the following examples. The following examples serve to illustrate certain preferred embodiments and aspects of the present invention and are not to be construed as limiting the scope thereof.
EXAMPLE 1
The Preparation of Nuclease-treated Rabbit Reticulocyte Lysate
[0037] Each animal was injected into the scruff of the neck with 4-5 ml of 1.25% (w/v) acetylphenylhydrazine (APH) solution each day on day 1, 2, and 3 of the schedule. An APH stock solution of 1.25% (w/v) in water was prepared on a heater-stirrer and stored at −20° C. The rabbits were normally bled on day 8 of the schedule. 0.5 ml of Hypnorm was injected into the thigh muscle. Once the Hypnorm had taken effect, and the rabbit rather dopey, the margin of one of the ears was shaved to expose the big marginal vein, which was injected with 2-2.5 ml of Nembutal or Sagatal containing 2000 units of heparin. When the animal was completely unconscious, the rabbit's chest was damped with 95% (v/v) ethanol, and the skin was cut away with a pair of sharp scissors. When the ribcage was well exposed, an incision from the bottom midline was made away, and up the midline toward the head, thereby making a triangular flap of flesh and bone with about 1-inch sides. The flap was folded open, and either the heart itself or one of the great vessels leading from the heart was cut. The chest cavity should rapidly be filled with blood, which was removed with a 30-50 ml syringe attached to a 3-inch long piece of silicone rubber or Tygon tubing into a chilled beaker in an ice bucket. An average of about 100 ml of blood was obtained from each rabbit.
[0038] The blood was filtered through cheesecloth or nylon mesh to remove hairs and debris. The cells were harvested from the blood by centrifugation with 500 ml polycarbonate bottles at 2,000 rpm for 10 min. After removal of the supernatant by aspiration, the cells were resuspended in buffered saline (5.5 mM KOAc, 25 mM Tris/acetate, 137 mM NaCl, 0.28 mM Na 2 HPO 4 .12H 2 O, 1 mM ethylenediaminetetraacetic acid (EDTA), and 1 mM dithiothreitol (DTT)) containing 5 mM glucose and spun again as before. The cells were washed additional three times, i.e., four low-speed spins altogether; on the last wash the volume of cells was determined by resuspending them in a measured volume of saline and measuring the total volume. After the final spin, as much of the saline as possible was removed and then 1.5 volumes (with respect to the packed cell volume) of ice-cold distilled water was added. The cells were mixed with the water thoroughly, and the contents of the different bottles were mixed with each other. The lysate was centrifuged for 20 min at 10,000 rpm (about 15,000 g) at 2° C. The supernatant was poured into a beaker through a fine nylon mesh (53 μm Nitex) to prevent any detached lumps of the glutinous stroma getting into the lysate; it contains inhibitor of protein synthesis.
[0039] For 400 μl of lysate, 8 μl of 1 mM hemin, 4 μl of 10 mg/ml creatine kinase solution, 3.2 μl of 125 mM CaCl 2 and 16 μl of 15,000 units/ml micrococcal nuclease solution were added and mixed thoroughly. The mixture was incubated for 30 min at 20° C. Digestion was stopped by adding 8.8 μl of 500 mM ethylene glycol-bis(2-aminoethyl ether)-N,N′-tetraacetic acid (EGTA); 4.8 μl of 10 mg/ml tRNA solution was added and mixed well. The lysate was dispensed in suitable aliquots of about 85 μl. The lysate was frozen in liquid nitrogen to achieve as rapid cooling as possible. Lysates stored in this way lost no activity over at least 3 years. Storage in a −70° C. freezer seemed to be satisfactory for periods of at least several months.
EXAMPLE 2
The Preparation of a Crude Homogenate From Chinese Hamster Ovary Cell
[0040] CHO cells were grown in two liters of cell culture media in 30 culture plates (15 cm diameter) at 34° C. for at least three generations (doubling time was approximately 20 h) to a density of about 5×10 5 cells/ml (4-6×10 7 cells per plate). Cells were removed from the plates by trypsinization. The medium was aspirated, and each plate was rinsed with 10 ml of Tris-buffered saline (5.5 mM KOAc, 25 mM Tris/acetate, 137 mM NaCl, 0.28 mM Na 2 HPO 4 .12H 2 O, 1 mM EDTA, 1 mM DTT, and 0.5 mM phenylmethylsulfonyl fluoride (PMSF) (pH 7.4)). Then each plate was rinsed quickly with 5 ml of Tris-buffered saline containing 0.05% (w/v) trypsin and 0.02% (w/v) Na 2 EDTA. After 5 min at room temperature, cells in each plate were suspended in 2 ml of ice-cold complete medium by pipetting and then pelleted by centrifugation for 5 min at 600 g at 4° C. The cell pellet was washed three times by repeated resuspension with 50-100 ml of Tris-buffered saline and centrifugation, and the packed cell volume was noted. The cell pellet was resuspended in homogenate buffer (250 mM sucrose, 10 mM Tris/acetate, 1 mM EDTA, 1 mM DTT, and 0.5 mM PMSF (pH 7.4)) to achieve a final volume equal to five times the volume of the cell pellet. A crude homogenate was made from this suspension of cells by stroking a very tight-fitting 15 ml Dounce homogenizer (Wheaton Co., Milliville, N.J.) 30 times. The crude homogenate obtained could be used at once or, more conveniently, frozen in liquid N 2 and stored at −80° C. for later subcellular fractionation.
EXAMPLE 3
The Preparation of Endoplasmic Reticulum Containing Signal Recognition Particle From a Crude Homogenate
[0041] Frozen homogenate was thawed rapidly at 30° C. immediately before subcellular fractionation and thereafter maintained in ice. This crude homogenate was centrifuged for 15 min at 5,000 g at 4° C. The supernatant from the first differential centrifugation was further fractionated to yield ER fraction. The supernatant containing ER membranes was gathered, diluted with 4 volume of homogenate buffer, and centrifuged for 5 min at 8,500 g at 4° C. to remove contaminating mitochondria. The supernatant was top-loaded onto a discontinuous sucrose gradient consisting of 2.0 M sucrose-10 mM Tris/acetate (pH 7.4), 1.5 M sucrose-10 mM Tris/acetate (pH 7.4), and 1.3 M sucrose-10 mM Tris/acetate (pH 7.4) in a v/v ratio of 3:4:4. This gradient was centrifuged for 150 min at 90,000 g at 4° C. (Beckman SW28 rotor at 23,000 rpm) and ER fractions were collected at the 1.3 M-15 M interface and the 1.5 M-2.0 M interface. Gradient layers were diluted with 3 volume of dilution buffer (55 mM Tris/acetate and 5 mM Mg(OAc) 2 (pH 7.0)) and centrifuged for 45 min at 90,000 g at 4° C. The sedimented pellet was solubilized with storage buffer (50 mM Triethanolamine, 2 mM DTT, and 250 mM Sucrose).
[0042] ER can be treated with staphylococcal nuclease (EC 3.1.31.1) to deplete it of endogenous mRNA activity. To 0.1 ml fraction of ER, 8 μl of 12.5 mM CaCl 2 solution was added. Staphylococcal nuclease was added to a final concentration of 600 units/ml. Digestion was carried out for 30 min at 20° C. and quenched by the addition of 2.2 μl of 0.5 M EGTA solution (adjusted to pH 7.5 with NaOH). This nuclease-treated ER was frozen in liquid N 2 in 50 μl aliquots and stored at −80° C. Prior to use, frozen ER was thawed rapidly by brief exposure to 30° C. and then maintained in ice.
EXAMPLE 4
The Preparation of Golgi Apparatus From a Crude Homogenate
[0043] The frozen crude homogenate obtained was thawed rapidly at 30° C. immediately before subcellular fractionation and thereafter maintained in ice. This crude homogenate was centrifuged for 15 min at 5,000 g at 4° C. After an initial centrifugation at 5,000 g, most of the supernatant was removed and the yellow-brown portion (upper one-third) of the pellet was resuspended in a small amount of supernatant. After mixing, the sucrose concentration of 6 ml portions of the crude homogenate was adjusted to 1.4 M by adding 6 ml of ice-cold 2.3 M sucrose containing 10 mM Tris/acetate (pH 7.4). The Na 2 EDTA concentration was adjusted to 1 mM by adding 100 mM stock solution. The mixture was vortexed vigorously to ensure uniform mixing, loaded into an SW 28 tube (Beckman), and overlaid with 14 ml of 1.2 M sucrose-10 mM Tris/acetate (pH 7.4) and then 8 ml of 0.8 M sucrose-10 mM Tris/acetate (pH 7.4). This gradient was ultracentrifuged for 150 min at 90,000 g at 4° C. (Beckman SW28 rotor at 23,000 rpm). The turbid band at the 0.8 M-1.2 M sucrose interface was harvested in a minimum volume (≦1.5 ml) by syringe puncture. Gradient layers were diluted with 3 volumes of dilution buffer (55 mM Tris/acetate and 5 mM Mg(OAc) 2 (pH 7.0)) and centrifuged for 45 min at 90,000 g at 4° C. The sedimented pellet was solubilized with storage buffer (50 mM Triethanolamine, 2 mM DTT, and 250 mM Sucrose). The fraction was immediately used or, more conveniently, frozen in liquid N 2 in suitable aliquots and stored at −80° C. The frozen Golgi apparatus fractions should only be thawed shortly before the assay by a minimal exposure to 30° C., and maintained in ice prior to use.
EXAMPLE 5
The Preparation of Plasma Membrane From a Crude Homogenate
[0044] The crude homogenate was centrifuged for 30 min at 25,000 g at 4° C. to prepare membrane-enriched microsome fraction. The supernatant was discarded and the pellets were resuspended in 0.2 M potassium phosphate buffer (pH 7.2) in a ratio of approximately 1 ml per pellet from 5×10 8 cells. The resuspended membranes then were loaded onto the two-phase system with a polymer mixture containing 6.6% Dextran T500 (Pharmacia Biotech), 6.6% (w/w) poly(ethylene glycol) 3350 (Fisher Scientific) and 0.2 M potassium phosphate (pH 7.2). The tubes were inverted vigorously for 40 times in the cold (4° C.). The phases were separated by centrifugation at 1,150 g for 5 min at 4° C. The upper phase containing primarily plasma membranes was diluted with 1 mM bicarbonate and collected by centrifugation at 30,000 g for 15 min.
EXAMPLE 6
The Production of EPO Via Coupled Cell-free Completely Post-translationally Modified Protein Synthesis
[0045] The plasmid, p64T-EPO containing the cDNA of human EPO with its authentic signal sequence (Boissel, J. P., et al., J. Biol. Chem. 268:15983-15993 (1993)) was purified with cesium chloride gradient ultracentrifugation and used as the template for coupled cell-free completely post-translationally modified protein synthesis. The cell-free completely post-translationally modified protein synthesis was carried out in the presence of the co- and post-translational modification machinery including glycosylation machinery besides the components of cell-free protein synthesis. The reaction mixture contained about 53% (v/v) nuclease-treated RRL and the final concentrations of other key components were: 17 mM creatine phosphate, 48 μg/ml creatine phosphokinase, 40 μM each amino acid, 260 units/ml SP6 RNA polymerase, 75 μg/ml circular plasmid DNA, 1.8 mM ATP, 1.3 mM GTP, 1 mM each of UTP and CTP, 50 mM potassium acetate, 3.6 mM magnesium acetate, 0.4 mM spermidine, 4 mM Hepes/KOH (pH 7.3), 1600 units/ml ribonuclease inhibitor, 2.7 mM DTT, 9.5 μM hemin, and 57 μg/ml calf liver total tRNA mixture. The reaction mixture was incubated. for 60 min at 30° C.
[0046] FIG. 1 shows an autoradiogram of completely post-translationally modified EPO by the method disclosed in the present invention and unmodified EPO that has been separated by SDS-polyacrylamide gel electrophoresis. Lane 1 shows EPO produced by cell-free protein synthesis without co- and post-translational modification machinery, Lane 2 shows EPO produced by cell-free completely post-translationally modified protein synthesis. In Lane 2 , the increase in molecular weight of the EPO molecule implies that EPO has been glycosylated.
[0047] FIG. 2 shows the result of western blotting of EPO produced by a conventional cell culture method and EPO produced by a cell-free completely post-translationally modified protein synthesis of the present invention. Lane 1 shows EPO produced by a conventional cell culture method, Lane 2 shows EPO produced by a cell-free completely post-translationally modified protein synthesis. As shown by Lane 2 , EPO produced by the present invention has the same molecular weight as EPO produced by conventional cell culture method and has the characteristic reactivity towards EPO specific antibody.
[0048] FIG. 3 shows an autoradiogram of EPO treated with glycosidase. Glycosidase selectively cleaves the carbohydrate chain from the protein. Lane 1 shows nonglycosylated EPO, Lane 2 and 3 shows glycosylated EPO, Lane 4 and 5 shows EPO treated with glycosidase F, and Lane 6 shows EPO treated with glycosidase H. It is reported that biologically active EPO possesses complex type oligosaccharide. This complex type oligosaccharide is known to be cleaved by glycosidase F and not by glycosidase H. As FIG. 3 shows, EPO produced by cell-free completely post-translationally modified protein synthesis is resistant to glycosidase H and cleaved by glycosidase F and thus contain the correct and complete complex-type oligosaccharide structure.
[0049] As the results of FIGS. 2 and 3 show, it can be concluded that EPO produced by cell-free completely post-translationally modified protein synthesis of the present invention contains the same structure as EPO produced by conventional cell culture methods.
[0050] For the solubilization of membrane, the reaction mixture was treated with 0.5% Triton. X-100. And then the synthesized EPO was immuno-purified with monoclonal antibody to EPO using general procedure.
[0051] After dialysis in refolding solution (50 mM sodium dihydrogenphosphate, 2% (v/v) sodium lauryl sarcosylate, 40 μM cupric sulfate), EPO was lyophilized. Purified EPO was subjected to biological activity test described as follow.
[0052] The biological activities of the purified EPO in vitro and in vivo were assayed by the growth of the EPO-dependent human cell-line, TF-1, cultured in RPMI 1640 medium containing 10% fetal calf serum (Kitamura, T. et al., Blood 73:375-380 (1989)) and by the incorporation of 59 Fe into erythroblast cells of exhypoxic polycythemic mice (Goldwasser, E. and Gross, M., Methods in Enzymol. 37:109-121 (1975)), respectively. Values were determined by a parallel line assay (Dunn, C. D. R. and Napier, J. A. P., Exp. Hematol. (N.Y.) 6:577-584 (1978)) using nine doses/sample and two wells/dose for the in vitro assay, and more than three doses/sample and three mice/dose for the in vivo assay. Any additives in the EPO preparations, such as salts, did not interfere with the assay when used at {fraction (1/500)} dilution with the medium. The highly purified recombinant human EPO (rHuEPO) calibrated by the second International Reference Preparation was used as standard. As predicted, the results conclude that the purified EPO showed similar in vitro and in vivo activities compared with the intact rHuEPO.
EXAMPLE 7
The Production of EPO Via Uncoupled Cell-free Completely Post-translationally Modified Protein Synthesis
[0053] The plasmid, p64T-EPO containing the cDNA of human EPO with its authentic signal sequence was purified with cesium chloride gradient ultracentrifugation and used as the template for in vitro transcription. In vitro transcription was carried out with or without cap structure, 7 mG(5′)ppp(5′)G. The final optimized concentrations of components for in vitro transcription without cap structure were: 40 mM Tris-HCl (pH 7.5), 6 mM magnesium chloride, 10 mM DTT, 1 mM each NTP, 1000 units/ml ribonuclease inhibitor, 2 mM spermidine, 1000 units/ml SP6 RNA polymerase, 10 mM sodium chloride and 0.1 mg/ml circular plasmid. The final optimized concentrations of components for in vitro transcription with cap structure were: 40 mM Tris-HCl (pH 7.5), 6 mM magnesium chloride, 10 mM DTF, 1 mM each ATP, CTT and UTP, 0.5 mM GTP, 1000 units/ml ribonuclease inhibitor, 2 mM spermidine, 1000 units/ml SP6 RNA polymerase, 10 mM sodium chloride, 0.5 mM cap analog and 0.1 mg/ml circular plasmid. To avoid precipitation of DNA with spermidine, the reaction mixture was pre-warmed at 37° C. prior to the addition of DNA. The transcription reaction was carried out at 37° C. for 4 h. For the isolation of synthesized RNA, the reaction mixture was extracted with phenol/chloroform and then with chloroform alone. RNA was selectively precipitated by addition of equal volume of 5 M LiCl and incubation in ice for 1 h. Then the mixture was centrifuged for 15 min at 5,000 g at 4° C. The resulting pellet was washed with 75% (v/v) ethanol and redissolved in RNase-free water. The uncoupled cell-free protein synthesis in the presence of the co- and post-translational modification machinery including glycosylation machinery was carried out. The reaction mixture contained about 53% (v/v) nuclease-treated RRL and the final concentrations of other key components were: 17 mM creatine phosphate, 48 μg/ml creatine phosphokinase, 40 μM each amino acid, 30 μg/ml RNA, 0.8 mM ATP, 0.3 mM GTP, 50 mM potassium acetate, 0.5 mM magnesium acetate, 0.4 mM spermidine, 4 mM Hepes/KOH (pH 7.3), 1600 units/ml ribonuclease inhibitor, 2.7 mM DTT, 9.5 μM hemin, and 57 μg/ml calf liver total tRNA mixture. The reaction mixture was incubated for 60 min at 30° C.
[0054] EPO produced by this method is shown in FIG. 4 to be the same as the EPO produced in example 6. In FIG. 4 , lane 1 shows EPO produced by cell-free protein synthesis without co- and post-translational modification machinery, lane 2 shows EPO produced by an uncoupled cell-free completely post-translationally modified protein synthesis and lane 3 shows EPO produced by a coupled cell-free completely post-translationally modified protein synthesis.
[0055] For the solubilization of membrane, the reaction mixture was treated with 0.5% Triton X-100. And then the synthesized EPO was immuno-purified with monoclonal antibody to EPO using general procedure. After dialysis in refolding solution (50 mM sodium dihydrogenphosphate, 2% (v/v) sodium lauryl sarcosylate, 40 μM cupric sulfate), EPO was lyophilized. Purified EPO was subjected to biological activity test described as example 6. As a result, the purified EPO showed similar in vitro and in vivo activities compared with the intact rHuEPO.
EXAMPLE 8
The Production of EPO Via Combination of Cell-free Completely Post-translationally Modified Protein Synthesis and Enzymatic In Vitro Glycosylation
[0056] The EPO produced by either coupled or uncoupled completely post-translationally modified protein synthesis system described in Examples 6 and 7 may be further modified by enzymes such as glycosyltransferase, glycosidase, and transglycosidase.
[0057] After the cell-free completely post-translationally modified protein synthesis, the reaction mixture was treated with 0.5% triton X-100 to solubilize the membrane. And the reaction mixture or affinity-purified EPO was treated with other modifying enzymes. This example describes the use of trans-sialidase. A crude preparation of trans-sialidase was obtained as described previously (Cavallesco, R. and Pereira, M. E. A., J. Immunol. 140:617-625 (1988); Prioli, R. P., et al., J. Immunol. 144:4384-4391 (1990)).
[0058] 5 μl of 0.5 μg/ml trans-sialidase was added to 15 μl of cell-free completely post-translationally modified protein synthesis reaction mixture containing 0.25 μmol of 2,3-sialyllactose or p-nitrophenyla-N-acetylneuraminic acid. In case of affinity-purified EPO, 10 μl of 0.5 μg/ml trans-sialidase was added to 40 μl of 50 mM cacodylate/HCl buffer (pH 6.9) containing 0.25 μmol of 2,3-sialyllactose or p-nitrophenyl-α-N-acetylneuraminic acid. After incubation at 30° C. for 18 h, the sialylated EPO was purified by affinity chromatography as aforementioned procedure in example 6 and subjected to methylation analysis. The sialylated product was converted to the corresponding permethylated monosaccharide alditol acetate as previously described (Scudder, P., et al., Eur. J. Biochem. 168: 585-593 (1987)). The derivatized samples were analyzed on a Hewlett-Packard 5890A capillary gas chromatography equipped with a 0.25 mm×30-m fused silica DB5 capillary column (J & W Scientific) which, after a 5-min hold time, was ramped from 150 to 230° C. at a rate of 2° C./min. The EPO treated with trans-sialidase featured a 10% elevation in sialic acid content and a 15% enhancement in biological activity.. On average sialic acid increased from 11.9 mol to 13 mol per mol of EPO.
[0059] From the above, it should be evident that the present invention provides an efficient and consistent cell-free completely post-translationally modified protein synthesis system. It should be understood that the present invention is not limited to the specific compositions or methods shown nor to the particular uses of the compositions described. In light of the foregoing disclosure, it will be apparent to those skilled in the art that substitutions, alterations, and modifications are possible in the practice of this invention without departing from the spirit or scope thereof.
EQUIVALENTS
[0060] Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to specific embodiments of the invention described specifically herein. Such equivalents are intended to be encompassed in the scope of the following claims. | The present invention relates to methods of production of the completely post-translationally modified protein by combination of cell-free protein synthesis and cell-free co- and post-translational modification. Previous cell-free protein synthesis system has only been capable of producing partially post-translationally modified protein but the present invention employs a co- and post-translational modification machinery that produces completely post-translationally modified protein. | 2 |
BACKGROUND OF THE INVENTION
This invention relates to electrical equipment used for conditioning electric power and, more particularly, to methods of controlling such equipment.
Active filters and power line conditioners utilize pulse width modulated (PWM) inverters with high frequency switching. In general, these applications require the inverter to supply harmonic and transient currents to a node on the power line with the objective of maintaining either a sinusoidal fundamental current on the line feeding the node, or a sinusoidal voltage at the point of connection, or both of these. Modern inverters can operate at quite high power levels with switching frequencies as high as 20 kHz. They are thus intrinsically capable of producing output currents of up to about the 40th harmonic of 60 Hz.
In the early development of these systems, the approach used was to establish closed loop control of the inverter currents with the highest possible bandwidth. Each event on the power line that caused the controlled quantity to deviate from the desired sine wave would then produce a corrective response from the controller. This is a reasonably effective approach, but it cannot completely eliminate any harmonics because of the limited dynamic response of the current controller. In the case where the current controlled loop is referenced by an outer voltage control loop, the ability of the voltage controller to reduce harmonics may be seriously limited.
Vector control techniques have been used in prior art motor control systems. In a vector control system, a controlled quantity (such as a three phase current in which the individual currents sum to zero) is represented by a single vector. That vector is then transformed onto a synchronously rotating frame of reference to produce a dc signal. The dc signal can then be integrated and subjected to an inverse transformation to produce an output signal which is used as a control signal to adjust the controlled quantity.
While prior art rotating frame controllers are very effective at tracking a single balanced set of three phase sine waves with zero error, they typically behave poorly in response to additional components of different frequency or phase sequence, due to system non-linearities. This invention seeks to apply a rotating frame control technique to systems such as active filters and power controllers which are subject to harmonic interference on the controlled power line.
SUMMARY OF THE INVENTION
This invention uses multiple frames of reference in the error path of a controller. In each such frame, a particular chosen component of the error vector appears as a constant vector and is passed through a pure integrator thus acquiring infinite gain. In the steady state, the net error vector can then be forced to have zero content at each of the targeted frequencies (as set by the rotational velocity of the frames of reference).
Control circuits constructed in accordance with this invention include a reference frame controller implemented in either a parallel or a series configuration. If a parallel implementation is used the control circuit comprises: means for producing an error signal vector in a fixed reference frame, with the error signal vector being representative of the difference between an output signal and a reference signal; a plurality of rotating frame controllers connected to receive the error signal vector, each of the rotating reference frame controllers including means for transforming the error signal vector onto a rotating frame of reference to produce an intermediate signal, means for integrating the intermediate signal to produce an integrated signal, and means for transforming the integrated signal onto the fixed frame of reference to produce a transformed integrated signal. The transformed integrated signals from each of the rotating frame controllers are combined to produce a control signal for use in controlling the output signal.
In the series implementation, the control circuit comprises: means for producing an error signal vector in a fixed reference frame, with the error signal vector being representative of the difference between an output signal and a reference signal; a plurality of series connected rotating frame controllers, each connected to receive at least a preselected component of the error signal vector, with each of the rotating reference frame controllers including means for transforming the preselected component of the error signal vector onto a rotating frame of reference to produce an intermediate signal, means for integrating the intermediate signal to produce an integrated signal, means for producing a signal representative of the error signal, and means for combining the integrated signal and the signal representative of the error signal to produce an output signal. The output signal of a preceding one of the rotating reference frame controllers serving as the input signal for a successive one of the rotating reference frame controllers. The output signal from the last one of the series connected rotating reference frame controllers is transformed onto the fixed frame of reference to produce a control signal.
This invention also encompasses the method of producing a control signal for controlling an output signal performed by both the parallel and series implementation of the circuits discussed above.
This invention makes it possible to eliminate selected steady state harmonics (voltage or current) in an active filter or power line conditioner using a pulse width modulated inverter, without the need for high bandwidth control loops.
BRIEF DESCRIPTION OF THE DRAWING
The invention will be more readily apparent to those skilled in the art by reference to the accompanying drawings wherein:
FIG. 1 is a vector representation of the instantaneous phase variables used in this invention;
FIG. 2 shows the vector of FIG. 1 in cartesian coordinates;
FIG. 3 is a block diagram of a vector control with a synchronously rotating frame of reference;
FIG. 4 is a block diagram of a rotating frame of reference as used in prior art motor control circuits;
FIGS. 5 and 6 are alternative implementations of the vector control of FIG. 4;
FIG. 7 is a block diagram of a current control circuit incorporating the present invention;
FIG. 8 is a block diagram of a voltage control circuit incorporating the present invention;
FIG. 9 is a block diagram of a parallel implementation of a multiple reference frame controller constructed in accordance with this invention; and
FIG. 10 is a block diagram of a series implementation of a multiple reference frame controller constructed in accordance with this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
It has been observed that the vast majority of distortions in multiple phase power line voltage are not transient phenomena, but rather periodic events comprising harmonics of the fundamental with positive or negative phase sequence. Once the magnitude and phase of these harmonics has been determined, they are fully defined until a change occurs. Therefore under steady state conditions, it is possible to set up an inverter, in an active filter or power line conditioner, to produce exactly the required harmonic currents without the need for a high-bandwidth controller. This is true irrespective of whether the controlled quantity is line current or voltage at the point of connection. Of course, a respectable control bandwidth may also be desirable to deal with any transient phenomena.
In the field of motor drive systems, vector control of the three phase currents in a synchronously rotating reference frame is an established technique. It is used to produce a desired set of alternating currents with zero fundamental error in the steady state. The theory of instantaneous symmetrical components gives a convenient representation of three instantaneous quantities that sum to zero, such as for example, the voltages or currents of a balanced three phase system. The three variables are instantaneously represented by a two dimensional vector whose vertical projections onto three symmetrically disposed axes have the same magnitude as the variables. This is illustrated graphically in FIG. 1 wherein the vector i is defined by its phase components i a , i b and i c . As shown in FIG. 2, the vector i can be represented by a complex number whose real and imaginary parts, i ds and i qs , correspond to the (ds, qs) coordinates. In this case,
i=(i.sub.ds +ji.sub.qs) (1)
For a case where vector i represents a balanced three phase sinusoidal set, it has a constant magnitude and rotates in the complex plane with an angular frequency equal to the frequency of the set. Since i a +i b +i c =0, i ds and i qs can be defined in terms of i a and i c as follows: ##EQU1## Alternatively, for the balanced three phase sinusoidal set, i can be represented as:
i=i.sub.0 e.sup.jωt (3)
where i 0 is a complex constant.
FIG. 3 illustrates the notion of a rotating reference frame controller 10 in terms of this vectorial notation. A desired vector i* is compared in summing point 12 with the measured actual vector i to produce an error vector i e on line 14. Block 16 shows that this quantity is multiplied by e -j ωt which corresponds to a rotation of the coordinate axes through the angle ωt. In this reference frame a component of the error vector with frequency ω, such as that described in equation (3), becomes a constant i 0 . The error signal is then passed through a pure integrator 18 which has infinite gain for this component. A further multiplication by e j ωt in block 20 returns the signal to the stationary ds-qs coordinate system. In practice, the output of this process is usually combined with a term proportional to the error vector (produced by the amplifier as illustrated by block 22) in combination with summation point 24, and the net transfer function of the controller is then: ##EQU2##
The important feature of this type of controller is that it provides a vector pole for vector components of rotational angular frequency +ω. The output of the controller may then be used to reference a three phase power amplifier such as an inverter, or to provide a reference to an inner control loop. In the steady state, it will then ensure that the +ω component of the error vector is reduced to zero.
FIG. 4 is a block diagram of a basic rotating frame controller as used in prior art motor control circuits An error vector signal i e is used to produce a voltage control signal v* by multiplying i e by e -j ωt as shown in block 26, integrating the result as shown in block 28 and multiplying the output of the integrator by e j ωt as shown in block 30. FIGS. 5 and 6 show alternative implementations of the controller of FIG. 4. In each case the direct and quadrature components of the error vector (i dse and i qse ) are used to produce direct and quadrature voltage control signal components V dse and V qse .
In FIG. 5, the direct and quadrature components of the error signal are transformed onto a rotating reference frame using the equations shown in block 32. The resultant signals, i de and i qe , include a constant component at the frequency defined by the rotational velocity of the rotating reference frame. These signals are integrated by integrators 34 and 36 to produce integrated signals v de and v qe , which are transformed using the equations in block 40, back to the original frame of reference, where they appear as output signals V dse and V qse .
In FIG. 6, the direct component, i dse , of the error signal vector is amplified as illustrated by block 42, and combined in summation point 44 with a feedback signal on line 46. The resulting signal is integrated as shown in block 48 to produce the output signal V dse . Similarly, the quadrature component, i qse , of the error signal vector is amplified as illustrated by block 50, and combined in summation point 52 with a feedback signal on line 54. The resulting signal is integrated as shown in block 56 to produce the output signal V qse . Multipliers 58 and 60 combine the output signals with a frequency signal ω to produce the feedback signals as shown.
FIG. 7 is a block diagram of a voltage control system constructed in accordance with this invention. A voltage reference generator 62 produces a voltage reference vector v in a first frame of reference. The voltage reference vector is combined with a feedback vector v in summation point 64 to produce an error vector v e . As discussed in detail below, preselected components of the error vector are transformed onto multiple rotating frames of reference by vector compensator 66 to produce direct and quadrature current reference signals i ds * and i qs *. These signals are subjected to a coordinate transformation in block 68 to produce phase current reference signals i a *, i b * and i c *. A controlled current source 70 uses these phase current reference signals to control the output current to a load, which in this example is represented by capacitors 72, 74 and 76 connected across a three phase power line. Voltages v a and v c are detected on lines 78 and 80, and subjected to a coordinate transformation in block 82 to produce the feedback vector v.
FIG. 8 is a block diagram of a current control system constructed in accordance with this invention. A current reference generator 84 produces a current reference vector i* in a first frame of reference. The current reference vector is combined with a feedback vector i in summation point 86 to produce an error vector i e . As discussed in detail below, preselected components of the error vector are transformed onto multiple rotating frames of reference by vector compensator 88 to produce direct and quadrature current reference signals v ds * and v qs * . These signals are subjected to a coordinate transformation in block 90 to produce phase voltage reference signals v a *, v b * and v c *. A controlled voltage source 92 uses these phase voltage reference signals to control the output current to a load, which in this example is represented by blocks 94, 96 and 98. Currents i a and i c are detected on lines 100 and 102, and subjected to a coordinate transformation in block 104 to produce the feedback vector i.
FIG. 9 shows a parallel path implementation of the invention for targeted frequencies of ω 1 , ω 2 , ω 3 , . . . , ω n . An error vector i e is supplied to a plurality of rotating frame controllers 106, 108, 110 and 112. Each of the rotating frame controllers includes a means for transforming the error vector onto a rotating reference frame, an integrator, and a means for transforming the output of the integrator back to the original frame of reference.
Different target frequencies ω n are used in each rotating frame controller. These target frequencies may be, for example, harmonic frequencies on a power line which is being controlled by an active filter or a power line conditioner. An amplifier 114 is used to produce a signal representative of the error signal. The resulting signal is combined with the outputs of the rotating frame controller in summation point 116 to produce a voltage reference vector v*. The transfer function of the circuit illustrated by FIG. 9 is: ##EQU3##
FIG. 10 shows a series path implementation of the invention for targeted frequencies of ω 1 , ω 2 , ω 3 , . . . , ω n . An error vector i e is supplied to a first one of a plurality of series connected rotating frame controllers 118, 120, 122 and 124. Each of the rotating frame controllers includes a means for transforming the error vector onto a rotating reference frame, an integrator, and a means producing a signal representative of the transformed error vector. The integrator output and the signal representative of the transformed error vector are combined in summation point sp n . Different target frequencies ω n are used in each rotating frame controller. These target frequencies may be, for example, harmonic frequencies on a power line which is being controlled by an active filter or a power line conditioner. The output of the last rotating frame controller is transformed in block 124 back to the original frame of reference to produce a voltage reference vector v*. The transfer function of the circuit illustrated by FIG. 10 is: ##EQU4##
Both implementations shown in FIGS. 9 and 10 provide n complex poles at the chosen frequencies, with n associated complex zeros located adjacent in the left half of the complex plane. Either of the techniques illustrated in FIGS. 5 or 6 can be used to implement the rotating frame transformations in the multiple frame controller.
Note that a targeted frequency may be either positive or negative. A positive value corresponds to a positive sequence three phase set and a negative value corresponds to a negative sequence set. If a positive frequency is targeted alone, then the corresponding negative sequence error set at the same frequency will not necessary be eliminated.
The multiple frame controller of this invention is based on the vector representation of three phase quantities arising from the theory of instantaneous symmetrical components. It is thus not applicable to single phase systems since these systems have no useful space vector interpretation.
This invention also encompasses a method of controlling active filters comprising the steps of: producing a first vector signal representative of an output signal to be controlled, with the first vector signal being referenced to a stationary coordinate system; comparing the first vector signal with a reference vector signal to produce an error vector signal; transforming the error vector signal onto a plurality of rotating frames of reference to produce a plurality of intermediate signals; integrating each of the intermediate signals to produce a plurality of integrated signals; transforming each of the integrated signals onto the first set of coordinates to form a set of transformed integrated signals; and combining the transformed integrated signals to produce a control signal for controlling the output signal.
Although the present invention has been described in terms of its preferred embodiments, it will be apparent to those skilled in the art that various changes may be made without departing from the scope of the invention, which is defined by the following claims. | An electrical control system includes multiple frames of reference in the error path of a controller. In each such frame, a particular chosen component of the error vector appears as a constant vector and is passed through a pure integrator thus acquiring infinite gain. In the steady state, the net error vector can then be forced to have zero content at each of the targeted frequencies (as set by the rotational velocity of the frames of reference). Both parallel and series configuration of the controller are provided, as well as the control methods used by the controllers. | 6 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the recovery of caustic from a lignin free solution of hemicellulose and caustic by electrolysis.
2. Description of Related Prior Art
In the production of high purity cellulose fiber used to manufacture rayon, cellulose based films. etc., pulp processed by conventional kraft pulping processes and bleached using chlorine, chlorate, and hydrogen peroxide, the pulp is highly delignified and very clean. The bleaching process steps are very aggressive since low fiber strength and low lignin content so as to obtain high brightness is essential. By the time the pulp enters the last bleaching stages, the lignin content of the pulp is very low. During the last bleaching stages, the hemicellulose and other wood sugars are removed utilizing caustic extraction. Fresh caustic is fed to these stages at a concentration of about 30 to about 35 percent by weight. In a final washing stage, clean water is used to wash away the hemicellulose from the pulp. The water dilutes the caustic solution of hemicellulose to provide a dilute solution off hemicellulose and caustic having a concentration of about 1 to about 10 percent, preferably, about 6 percent by weight caustic. The dissolved hemicellulose gives this solution a brown color. In the paper mill, some of the hemicellulose caustic solution is evaporated to 35 percent caustic content by weight and recycled for use in other parts of the paper mill where the hemicellulose content of the caustic solution is not detrimental such as the initial pulp bleaching and extraction stages in the process.
Because the recovery system for recovering pulping chemicals often represents the critical production limitation in the kraft pulping process because of the limited capacity inherent in the high capital cost for such a recovery system, the capacity of the paper mill to process the entire hemicellulose caustic solution often is inadequate and, accordingly, other methods of recovering a caustic solution, preferably, free of hemicellulose, are needed.
In U.S. Pat. No. 5,061,343, a process is disclosed for the recovery of sodium hydroxide and other values from spent liquors and bleach plant effluents in a kraft pulping mill. This patent discloses a process for removing lignin from an aqueous alkaline liquid by a combination of electrolytic acidification of this liquid and chemical acidification.
U.S. Pat. No. 4.584,076 is cited in the above patent as disclosing a method of treating sulfur-free spent liquors in an electrolysis cell to recover lignin and sodium hydroxide.
It is considered that these references are not directly relevant prior art to the inventive process disclosed herein for the electrolytic recovery of sodium hydroxide and other values such as hemicellulose, oxygen and hydrogen utilizing an electrolytic cell to concentrate an aqueous solution of hemicellulose caustic so as to allow recycling of the sodium hydroxide contained therein.
SUMMARY OF THE INVENTION
In accordance with the invention, a process is disclosed for recovering a purified, concentrated caustic solution from a dilute, essentially lignin free, solution of hemicellulose and caustic obtained as a paper mill discharge stream. A novel electrolytic cell of the filter press type constructed of polyvinyl chloride sheets, preferably, utilizing a bipolar electrode configuration has been found particularly effective for use in the process of the invention. The anode and cathode of the cell can be separated by a any suitable cation exchange membrane cell separator and the preferred bipolar electrode is bonded to individual anode and cathode current collectors utilizing a ductile polyester resin based on a elastomer modified vinyl ester having an elastomeric monomer grafted onto the vinyl ester polymer backbone. The anode and cathode can be any stainless steel or mild steel. Preferably, a 316 stainless steel mesh or a platinum-iridium coating on a ruthenium-titanium mesh substrate is used with a 316 stainless steel wire mesh cathode. Both anode and cathode are separated by stand-off posts in electrical contact with individual current collectors which are in turn bonded with the above described ductile polyester resin which is made electrically conductive by the incorporation of a suitable amount of graphite powder. The electrolytic cell frames of polyvinyl chloride are also bonded with a ductile polyester resin as described above.
By the process of the invention, a dilute, essentially lignin free solution of hemicellulose and caustic is led to the anolyte of an electrolytic cell which is operated at a temperature of about 20° C. to about 100° C. Deionized water is fed to the catholyte compartment of the cell. By the process of the invention, a caustic solution can be withdrawn from the catholyte of said cell at a concentration of up to about 490 grams per liter, preferably, about 150 to about 180 grams per liter while the concentration of caustic in the anolyte of said cell is reduced to about 10 to about 20 grams per liter without precipitation of hemicellulose. Upon withdrawing the hemicellulose solution from the electrolytic cell subsequent to electrolysis, the hemicellulose is precipitated and can be filtered for further use or incineration.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In accordance with the invention, an aqueous, essentially lignin free solution of hemicellulose and caustic can be concentrated by electrolysis in an electrolytic cell so as to allow removal of hemicellulose from a major amount of the caustic. The caustic can be further concentrated by evaporation so as to permit recycling of the caustic solution to the hemicellulose extraction stage of a pulp mill in a process to make very short, low strength, high purity cellulose fiber used to manufacture rayon, cellulose films, etc.
Both solid and liquid recovery are the critical production limitations at a kraft mill. Methods to reduce the load on the recovery boiler of the pulp mill have been described in U.S. Pat. No. 5,034,094; U.S. Pat. No. 5,374,333; U.S. Pat. No. 5,370,771; and U.S. Pat. No. 5,061,343. These prior art references relate mainly to methods of treatment and recovery of values from pulp mill black liquor which is removed from the process stream for processing. Where a pulp mill process has the object of producing very short, low strength, high purity cellulose fiber for use in the manufacture of rayon, cellulose films etc., the pulp has not only to be highly delignified but in addition, the pulp has to be free of hemicellulose and other wood sugars. These are removed from the pulp by a final purification extraction step utilizing a fresh caustic solution fed to the extraction step of the process at a concentration of about 30 to about 35 percent. Subsequently, a final pulp aqueous washing step is used to wash away the hemicellulose and caustic leaving the desired high purity cellulose fiber. These steps of the pulp mill purification process produce a mixture of hemicellulose and caustic of about 1 to about 10 percent caustic by weight, preferably, as a 6 percent by weight caustic solution. This solution is brown in color as a result of the dissolved hemicellulose. While most of the hemicellulose and caustic solution is normally evaporated to a 35 percent by weight concentration in triple effect evaporators and reused in other parts of the pulp mill where the hemicellulose content is not detrimental to the process such as in the initial bleach and extraction stages, a portion of this 6 percent hemicellulose caustic solution is withdrawn from the process stream and neutralized before disposal to the environment. A portion of this 6 percent hemicellulose and caustic solution can not be reused in the pulp process necessitating the expense involved in the neutralization and the added expense and environmental damage which result by discharge of this solution into a treatment lagoon as an undesirable alternative to the process of the invention.
It is an object of the process of the invention to electrolyze a hemicellulose and caustic solution to achieve a concentration of about 1 to 5 percent by weight caustic in the hemicellulose solution recovered from the anolyte compartment of the electrolysis cell after conducting electrolysis. This solution may be filtered or centrifuged to remove the hemicellulose leaving a solution containing only about 10 to about 30 percent by weight of the original caustic content.
Alternatively, the 6 percent hemicellulose and caustic solution can be concentrated to a caustic content of about 25 percent by weight, by conducting the electrolysis again so as to retain only 1 to 3 percent by weight caustic in the hemicellulose solution after electrolysis. In this alternative process, approximately 90 to about 95 percent by weight of the caustic present in the incoming hemicellulose caustic solution would be recovered.
A third alternative to the treatment of the 6 percent hemicellulose caustic solution would be to concentrate this solution to a concentration of 25 percent by weight and subject this solution to a turbulent flow electrodialysis cell as disclosed in U.S. Pat. No. 5,334,300 so as to remove about half of the caustic present in the incoming hemicellulose and caustic solution and, subsequently, remove approximately the second half of the caustic from the incoming hemicellulose caustic solutions by electrolysis as indicated above.
The electrolytic cell utilized in this process is, preferably, a filter press type electrolysis cell which is constructed utilizing polyvinyl chloride sheets bonded with a ductile elastomer modified vinyl ester polymer characterized by the presence of an elastomeric monomer bonded to the backbone of the polymer. Prior to assembly, the polyvinyl chloride electrolytic cell frames are provided with anolyte and catholyte feed channels and the bonding areas are subjected to sandblasting or other methods of mechanically or chemically abrading or etching the surface so as to improve the strength of the bond.
Where both the anode and cathode are mild steel or any stainless steel, preferably, 316 stainless steel, the cell has a unique bipolar electrode configuration in which a single current collector is attached to the anode and the cathode of the cell. Where the anode and cathode are of dissimilar metals, a bipolar electrode is formed by adhering anode and cathode current collectors with the same elastomer modified vinyl ester polymer made electrically conductive by the addition of a suitable amount of powdered graphite or a powdered metal, such as copper, gold, or silver.
The cell separator is any suitable ion exchange permselective cation-exchange membrane. Examples of cation-exchange membranes are those formed from organic resins, for instance, urea formaldehyde resins or resins obtained by polymerization of styrene and/or divinylbenzene, fluorocarbon resins, polysulfones, polymethacrylic or phenoxy resins or vinyl chloride polymers. Such resins can also be employed as mixed polymers or copolymers. Generally, resins with sulphonic groups are preferred, and among these polyfluorocarbon resins which contain cation-exchange groups are useful. Preferably, a vinyl chloride polymer based cation-exchange membrane sold under the tradename Ionics CR65 is used.
In the following Examples there are illustrated the various aspects of the invention but these Examples are not intended to limit the scope of the invention. Where not otherwise specified in this specification and claims, temperature is in degrees centigrade and percentage is by weight.
EXAMPLE 1
In this Example a 6 percent by weight caustic solution of hemicellulose and caustic was electrolyzed in an electrolytic cell so as to obtain an anolyte volume reduction from electrolysis of 16 percent. This is obtained by a combination of water loss through oxygen evolution and water movement with cations through the cation-exchange permselective membrane cell separator. Total caustic recovery obtained by withdrawal from the catholyte compartment of the electrolytic cell was 76 percent. The electrolyzed hemicellulose caustic solution removed from the anolyte compartment did not precipitate during electrolysis cell operation at 55° to 60° C.
The electrolysis cell was a single bipolar electrolysis cell having a polyvinyl chloride filter press type frame glued after sandblasting the areas to be bonded with an elastomer modified vinyl ester polymer having an elastomeric monomer grafted onto the backbone of the polymer. The cell frames are bonded together to form an electrolysis cell having an active area measuring 46.5 inches high and 4 inches wide. The cell separator used was a vinyl chloride polymer based cation-exchange permselective cell membrane having cation-exchanging radicals. The anode used in the cell was a platinum and iridium coating on a ruthenium and titanium mesh substrate. The anode was spot-welded to a titanium substrate current collector on stand-off posts. The cathode used was 316 stainless steel wire mesh spot-welded to a 316 stainless steel substrate on stand-off posts connected to a cathode current collector. Bipolar contact between the anode and cathode current collectors was made by utilizing an electrically conductive cement which is a mixture of powdered graphite and a vinyl ester polymer having an elastomeric monomer grafted onto the vinyl ester polymer backbone to provide a more ductile and flexible polyester. Graphite powder having a particle size of about 10 microns was present in the proportion of about 40 percent by weight of the mixture. The electrode to separator gaps for both anode and cathode were 0.040 inches to 0.060 inches. The cell was operated under the following test conditions: 1.07 amps per square inch; total cell amperage was 193 amps. A head pressure of 12 inches was maintained on the anode side of the cell. The anode feed rate was 123 milliliters per minute. The anode overflow rate for the spent hemicellulose solution was 103 milliliters per minute. The anode feed was 63 grams per liter of sodium hydroxide and 16 to 18 grams per liter equilibrium concentration in the anode compartment. The cathode feed was deionized water which was fed at a rate of about 16 milliliters per minute. The cathode overflow was about 36 milliliters per minute. A sodium hydroxide equilibrium concentration in the cathode compartment of 160 to 170 grams per liter was obtained. Electrolyte recirculation in both compartments of the cell was obtained by gas lift only. The cell was operated at a temperature of 55° to 60° C. by providing cooling utilizing a cooling coil in a cathode gas disengager tank. The temperature differential across the separator was about 5° C.
EXAMPLE 2
In a second experiment utilizing the above cell the cell anolyte was electrolyzed to obtain a concentration of 10 grams per liter of sodium hydroxide with no hemicellulose precipitate being formed in the cell while operating at a cell temperature of 55° to 60° C. When the anolyte solution was removed from the cell, allowed to stand, and cool, a white precipitate formed. This precipitate settles to occupy a volume of about 66 percent of the original volume of the solution upon standing overnight.
While this invention has been described with reference to certain specific embodiments, it will be recognized by those skilled in the art that many variations are possible without departing from the scope and spirit of the invention, and it will be understood that it is intended to cover all changes and modifications of the invention disclosed herein for the purpose of illustration which do not constitute departures from the spirit and scope of the invention. | Pulping chemicals and hemicellulose are recovered from a starting solution essentially free of lignin but containing a mixture of hemicellulose and caustic by electrolyzing this solution in the anolyte compartment of an electrolytic cell. By electrolysis, the concentration of caustic in the anolyte is decreased and the concentration of caustic in a catholyte of said cell is increased so as to allow recovery, of about 60 to about 80 percent of the caustic contained in the hemicellulose caustic starting solution. | 3 |
This is a continuation of application Ser. No. 08/085,512 filed on Jun. 30, 1993 is now abandoned.
FIELD OF THE INVENTION
The present invention relates to an input device for a visual display screen.
BACKGROUND OF THE INVENTION
Input devices for visual display screens are particularly useful in cluttered computing environments where conventional data entry devices such as keyboards and mice are impractical because they occupy valuable working space.
U.S. Pat. No. 4,558,313 describes an example of a conventional electromechanical optical input device in which first and second light beams are scanned across a plane display screen by mechanical rotating beam scanners. The first light beam is scanned from one side of the screen and the second light beam is scanned from the other side. To operate the touch screen, an operator places a stylus at a desired location on the screen. The stylus interrupts portions of the light beams that would otherwise be reflected back towards their respective sources by retroreflective strips. In response to detection of the reflected portions at the sources, via photodetectors, the location of the stylus is determined from the respective angular positions of the two light beams incident on the stylus.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is now provided an input device for a visual display, the device comprising: a light source; a scanner for angularly scanning a light beam from the light source across a plane; and a photodetector for detecting interruption of the beam by an article positioned in the plane; characterized in that the scanner comprises a shutter having a linear array of addressable, electrically actuable, shutter elements, each element being individually operable to transmit or block light from the light source under the control of a corresponding electrical signal.
Because the light beam is scanned by a shutter rather than a mechanical scanner, an input device of the present invention is advantageously more reliable than conventional electromechanical optical input devices.
The device preferably comprises a processor for determining the position of the article in response to the photodetector detecting the presence of the article and as a function of the address or addresses in the array of the element or elements transmitting the interrupted beam or beams.
Because there is no inertia associated with the shutter, an input device of the present invention can advantageously track any motion of the article at higher speeds than conventional electromechanical optical input devices.
In a preferred embodiment of the present invention, the processor is adapted to track the position of the article in the approximate plane by actuating only elements of the array transmitting interrupted beams. This advantageously permits still faster tracking of the stylus and furthermore enables the input device to be serviced by less processing power.
The scanner may, for convenience and simplicity, comprise a diverging lens for generating a diverging envelope of light beams from light generated by the light source.
The scanner may comprise a mirror for directing the diverging envelope of rays towards the shutter. The mirror advantageously reduces the space required for implementing the present invention.
The light source preferably comprises a condenser for producing a substantially collimated light beam. This advantageously improves the sensitivity of the present invention by increasing the intensity of the light beam detected by the photodetector.
Preferably, the light source is driven by a pulse signal to generate pulses of light. This advantageously provides a further improvement in the intensity of the light beam detected at the photodetector.
The photodetector is preferably phase-locked to the pulse signal to advantageously improve the signal to noise ratio of the photodetector.
Preferably, the photodetector comprises a bandpass filter adapted to substantially prevent the photodetector from detecting light of wavelengths that are not generated by the light source. This advantageously provides a further improvement in the signal to noise ratio of the photodetector.
It will be appreciated that the present invention extends to a display device, such as for example a liquid crystal display or a CRT display, comprising an input device as hereinbefore described.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the present invention will now be described with reference to the accompanying drawings in which:
FIG. 1 is a block diagram of an input device of the present invention;
FIG. 2 is a block diagram of a transceiver for the input device;
FIG. 3 is a block diagram of the transceiver in operation;
FIG. 4 is a block diagram of a liquid crystal shutter for the transceiver;
FIG. 5 is a block diagram of the input device in operation; and
FIG. 6 is a block diagram of another transceiver for the touch sensitive input device.
DETAILED DESCRIPTION OF THE INVENTION
Referring first to FIG. 1, an example of an input device of the present invention comprises two light transceivers 10,20 mounted on opposite sides of bezel 30 that can be releasably secured to screen 40 of a visual display (not shown). Transceivers 10,20 receive electrical control signals from, and transmit electrical output signals to, processor 60. Processor 60 has digital output 50 that may be connected to an input/output adaptor such as a mouse part of a host computer system such as a personal computer (not shown).
Referring now to FIG. 2, each transceiver 10,20 comprises a light source in the form of laser diode 210 directed towards cylindrical lens 270. The face of lens 270 remote from laser diode 210 is silvered with semireflective mirror 220. Mirror 220 is directed towards linear array liquid crystal shutter 260 having N addressable elements 300a-300n. Shutter 260 may be manufactured from Ferroelectric Smectic LC material or from Stacked Nematic Pi Cells. Elements 300a-300n are electrically configured by drive signals from shutter driver circuit 250 to either permit or block passage of light. Shutter driver circuit 260 receives control signals from processor 60. Photodetector 230 is located behind mirror 220. The output of photodetector 230 is connected to processor 60. Lens 270 is shaped to direct the divergent envelope of rays from laser diode 210 towards mirror 220 and to focus rays directed from shutter 260 towards mirror 220 onto photodetector 230. It will be appreciated however that, in other embodiments of the present invention, single cylindrical lens 270 may be replaced by separate diverging and converging lenses.
Referring to FIG. 3, in each transceiver, lens 220 converts a light beam generated by laser diode 210 into a divergent envelope of rays that substantially fills mirror 220. Mirror 220 partially reflects the envelope to generate a divergent fan of rays that would extend, in the absence of shutter 260, to substantially cover the area of screen 40 in a 90 degree arc. However, as illustrated in FIGS. 3 and 4, driver circuit 250 configures elements of shutter 260 in such a manner that, at any instant in time, one of the elements 300 is transparent to the rays and the remaining elements are opaque. Thus, at any instant in time, only one ray of the fan is permitted to extend across screen 40.
With reference to FIG. 4, driver circuit 250 generates drive signals arranged to progressively move transparent element 300 along shutter 260 from one end to the other. Thus, in operation, shutter 260 acts like a moving slit with each element 300 in turn admitting a different ray of the fan. A beam of light is thereby effectively scanned across screen 40. Each element remains transparent for a matter of microseconds. For the purpose of explanation, the shutter is depicted in FIG. 4 as having ten elements. In practice however, to achieve acceptable sensitivity, the shutter may have more than a hundred elements.
Turning now to FIG. 5, to operate a touch sensitive input device of the present invention, an operator positions retroreflective stylus 500 at a desired location on screen 40. Portions of the light beams incident on stylus 500 are reflected back towards their respective sources 10,20. At each transceiver 10,20, the reflected portion passes through transparent element 300 of shutter 260 towards lens 270. A fraction of the reflected portion passes through mirror 220 to be focused by lens 270 onto photodetector 230. This produces a change in the output of photodetector 230. The change in the output triggers processor 60 to read the address in shutter 260 of transparent element 300. Processor 60 determines the angular position of the incident ray from the address of transparent element 300. The position of the stylus on screen 40 is identified by the intersection x of incident rays, AB and CD, from two transceivers 10,20. Processor 60 determines the intersection from the angular positions of the incident rays with respect to a common datum.
Because the rays extending across the screen are divergent, stylus 500 may be detected through several elements of shutter 260. The position of stylus 500 may therefore be determined by convolution of the angular positions. When processor 60 detects the presence of the stylus through more than one element of one or both of the shutters, only those elements, together with enough on either side of them to permit limited overscanning, are addressed. Any motion of the stylus can therefore be detected at higher speed than previously possible. This advantageously permits faster tracking of the stylus and enables the touch screen to be serviced by less processing power.
It will be appreciated that the light generated by light source 210 may be of a wavelength or wavelengths within the visible region or invisible regions of the Electromagnetic Spectrum.
Referring now to FIGS. 1 and 6, in a preferred example of the present invention, bezel 30 carrying transducers 10,20 has a diagonal length of 356 mm. In both transceivers 10,20, the light beam generated by laser diode 210 is collimated to a diameter of approximately 2 mm by an optical condenser 600 having an optical efficiency of about 40%. Liquid crystal shutter 260 is about 70% efficient and has first and second polarizer efficiencies of around 40% and 80% respectively. The optical efficiencies of mirror 220 and lens 270 are around 70% and 80% respectively. Mirror 220 has both reflection and transmission efficiencies of approximately 45%. Lens 270 is shaped to diverge the light beam from laser diode 210 across approximately 90 degree arc. The long pulsed mean power emission from laser diode 210 is of the order of 5 mW/steradian and diode output power efficiency is 5%. However, in operation, laser diode 210 is actuated by 100 us pulses at duty cycle of 100 us to produce a mean power emission of about 50 mw/steradian. The apparatus is operated with a 2 mm diameter stylus 500 reflecting around 50% of an incident beam. Photodetector 230 comprises a phototransistor producing an output current response of about 4.10E-2 A/W/cm*2 superposed on a dark current of approximately 2.10E-9 A. Optical bandpass filter 610 located between lens 270 and photodetector 230 removes stray light. The output of photodetector 230 is phase-locked to the pulses actuating laser diode 270 by phase-lock loop circuit 620 to improve the signal to noise ratio.
The optical efficiency of the preferred embodiment of the present invention described in the preceding paragraph is a factor of about 5000 less than that of the aforementioned conventional electromechanical optical touch sensitive input device based on a 2 mm collimated beam.
In operation, the photodetector 230 produces photocurrent of about 1.5×10E-6 in response to background illumination and about 2.4×10E-7 in response to an incident ray reflected by the stylus and transmitted by mirror 220. If condenser 600 is omitted, the photocurrent produced by photodetector 230 in response to the incident ray is reduced by a factor of around 20 to 1.2×10E-8 A. If laser diode 210 is operated continuously instead of pulsed, the photocurrent produced by photodetector 230 in response to the incident beam is reduced by a further factor of about 10 to 1.2×10E-9 A. In other words, if the condenser is omitted and laser diode 210 is operated continuously, the photocurrent produced by photodetector 230 in response to the incident beam would be reduced to noise level and would therefore be undetectable.
While several embodiments of the invention, together with modifications thereof, have been described in detail herein and illustrated in the accompanying drawings, it will be evident that various further modifications are possible without departing from the scope of the invention. Nothing in the above specification is intendedto limit the invention more narrowly than the appended claims. The examples given are intended only to be illustrative rather than exclusive. | An input device for a visual display comprising a light source and a scanner for angularly scanning a light beam from the light source across a plane. A photodetector detects interruption of the beam by an article positioned in the plane. The scanner comprises a shutter having a linear array of addressable, electrically actuable shutter elements. Each element is operable to transmit or block light from the light source under the control of a corresponding electrical signal. Because the light beam is scanned by a shutter rather than a mechanical scanner, the device is advantageously more reliable than conventional electromechanical optical input devices. | 6 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to the art of configurable billing systems. The invention finds application in document processing equipment and will be described in reference thereto. However, the invention can be applied wherever a product or service is performed through the use of a machine. The invention is particularly applicable where the product or service can be delivered with a wide variety of optionally purchased aspects or features.
[0003] 2. Description of Related Art
[0004] The demands of the marketplace have and will continue to drive the development and proliferation of a wide variety of document processing equipment. Traditionally, when an untapped and profitable market segment is discovered, a development effort produces a new document processing system that is custom designed to meet the needs of the newly discovered market segment. The custom design has typically included the use of new or customized components, such as, for example, sensors, actuators, and user interfaces, as well as new software. The new or custom components are selected based on cost versus performance requirements of the market segment. The appropriate new software is written to accommodate features of the new components. Such development projects have even included the re-writing of billing or metering software. This has been necessary since different devices or market segments require different billing strategies.
[0005] For example, in markets where customers object to being billed for diagnostic document processing, features have evolved that allow diagnostic document production runs to be identified and omitted from a customer's bill. For example, some document processing systems include shadow meters. Shadow meters record the same kinds of events that are recorded by standard meters. However, shadow meters record the events, for example, only during diagnostic document production runs. The values stored in the shadow meters are subtracted from the values stored in the standard meters before a customer's bill is generated. Other devices use diagnostic flags. Diagnostic flags indicate, for example, that standard meters should not be updated, since the current processing is related to the diagnostic activities of a service technician. Diagnostic flag operation requires less system memory. Therefore, it is the technique of choice in cost sensitive designs. However, diagnostic flag operation has a drawback. In diagnostic flag operation, system wear information is lost. The system “mileage” that accrues during diagnostic procedures is not recorded when diagnostic flags are used to stop the “odometers”. Therefore, the use of diagnostic flags can have detrimental effects on, for example, preventive maintenance scheduling.
[0006] In some markets, customers expect a discount for large production runs. Therefore, some document processing systems include meters that record impressions that are to be discounted. For example, a discount impression meter is incremented only if five hundred or more impressions have been made before the current impression.
[0007] Some products can serve several markets. However, because of different market pressures in the several markets, the machines must be configured to bill differently in each of the several markets. Where billing software is “hard coded” into the image processor, adapting machines to these various markets is problematic. Each software version must be written, tested and maintained separately. On the other hand, if a problem is discovered in one version, all the other versions must be checked in order to determine if the problem is common to all versions or limited to only one version. In short, hard coded billing software is expensive and inflexible.
[0008] Still other products have evolved to provide some meters that are resettable, while maintaining others to be secure and guaranteed not to be resettable.
[0009] As each new image processor has been developed, it has been deemed reasonable or expedient to develop new billing software along with the new document processing system, in order to provide required new features or new combinations of features. One reason for this is that there has been no easy to use alternative.
[0010] The high cost of product development and market pressures for fast design turn around have lead to a desire for modular designs. Modular designs allow new products to be created by re-configuring and rearranging available components and sub-assemblies. Software, including billing software, represents a time consuming and expensive aspect of new product development. Therefore, there are strong market pressures to reuse previously developed software. However, it has been difficult to write software that can be reused in future designs when the features and requirements of future designs are unknown.
BRIEF SUMMARY OF THE INVENTION
[0011] The present invention is a solution to the design for reuse problem in general, and for billing software reuse in particular.
[0012] In one aspect of the present invention, a configurable billing system for a machine is provided, the machine being operative to output a product or service. The machine comprises a plurality of aspect sensors. The sensors detect the delivery of aspects of the product or service and report the delivery to the billing system. The billing system operates to tally aspects of the output of the machine. The billing system comprises a coded billing strategy delivered by the machine to the billing system, and a plurality of meters updated by the billing system for recording the delivery of the aspects of the product or service in a manner described by the billing strategy.
[0013] One embodiment of the present invention comprises a configurable billing system for a document processing system, where the document processing system operates to produce documents. The document processing system comprises a plurality of aspect sensors operative to detect document production events and to report aspects of document production to the billing system. The billing system operates to record the reported aspects. The aspects are recorded, for example, in order to calculate charges for a bill of a customer. The billing system comprises a billing strategy description delivered by the document processing system to the billing system, a plurality of meters, and a billing module operative to update the plurality of meters according to the billing strategy.
[0014] Another aspect of the invention comprises a method for developing and using a universal billing module. In some embodiments the method comprises predefining a billing strategy, wherein the billing strategy includes a list of parameters and process algorithm information, and storing the billing strategy in a machine-readable form. Preferably, the list of parameters includes implicit or explicit communication mechanisms, and data parsing information.
[0015] One advantage of the present invention is found in a reduction in time to market the invention provides new product developments.
[0016] Another advantage of the present invention is that custom billing module functionality is provided through the relatively simple generation of a billing strategy.
[0017] Yet another advantage of the present invention resides in the ability to easily change or update the functionality of a machine, either at the factory, to satisfy the needs of a new market, or in the field, to customize the machine for a new task.
[0018] Still other advantages of the present invention will become apparent to those skilled in the art upon a reading and understanding of the detail description below.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0019] The invention may take form in various components and arrangements of components, and in various steps and arrangements of steps. The drawings are only for purposes of illustrating preferred embodiments, they are not to scale, and are not to be construed as limiting the invention.
[0020] [0020]FIG. 1 is a block diagram of a first document processing system including a universal billing module;
[0021] [0021]FIG. 2 is a first billing strategy operative to configure the universal billing module to operate within the environment of the first document processing system;
[0022] [0022]FIG. 3 is a block diagram of a second document processing system including a universal billing module;
[0023] [0023]FIG. 4 is a second billing strategy operative to configure the universal billing module to operate within the environment of the second document processing system; and
[0024] [0024]FIG. 5 is a flow chart summarizing a method for developing and using a reusable billing module.
DETAILED DESCRIPTION OF THE INVENTION
[0025] Referring now to the drawings wherein the showings are for purposes of illustrating the invention and not for purpose of limiting the same thereto, FIG. 1 is a block diagram of a first document processing system 110 . The first document processing system 110 comprises a controller 114 and an A-type print engine 118 . For example, the A-type print engine 118 is a XEROX DocuTech 6180 xerographic print engine. The controller 114 comprises hardware and software modules 122 for controlling and operating the document processing system 110 . The modules 122 are in communication with sensors 124 directly or indirectly. For example, document processing system 110 may contain sensors 124 . The sensors 124 can be real sensors distributed throughout the A-type print engine 118 and/or virtual sensors, distributed throughout software modules of the A-type print engine 118 (not shown) and/or controller 114 . Sensors are discussed in greater detail in reference to FIG. 4 below. The modules include an A-type marker 126 module. The A-Type marker 126 is a module specifically designed for controlling and taking advantage of the features and capabilities of A-Type print engines 118 . For example, the A-type marker 126 is a Xerox DocuTech 6180 marker module, designed to control and take advantage of features of a Xerox DocuTech 6180 print engine. The A-type marker 126 is in communication with a universal billing module 130 . The billing module 130 may be part of the controller. Alternatively, the billing module 130 is separate from the document processing system 110 and simply in communication with the document processing system 110 . For example, the billing module 130 may be in communication with the first document processing system 110 via a computer network.
[0026] The billing module 130 is a universal software module. The billing module 130 is universal in that it accepts configuration information and data from, for example, any marker module. Alternatively, a billing module may read this information directly from files and/or sensors. Therefore, the billing module 130 is able to record billable events and activities of any kind and in any combination. This universality is provided by the ability of the billing module to receive, decipher, and implement a billing strategy or set of billing instructions from another module or device. For example, the billing module 130 receives a strategy description from the A-type marker 126 . The strategy is preferably stored in an available storage device of the controller 114 . Alternatively, the strategy is read and accessed directly by the billing module 130 .
[0027] Referring to FIG. 2, a first billing strategy 210 comprises, for example, a list of parameters 214 or aspects of interest and a list of meter descriptions 218 .
[0028] The parameter list 214 is arbitrarily long and contains parameters, for example, P 1 through Pn. The parameter list 214 informs the billing module 130 of the billable events or activities a marker module is capable of reporting. Furthermore, the parameter list 214 explains the format in which the marker 126 will communicate the parameters to the billing module. For example, the parameter list includes an impression flag. Alternatively or additionally, the parameter list may include a count of total impressions made parameter. An impressions flag is used to indicate that the marker 126 has issued commands to the print engine 118 causing the print engine to print an image on, for example, one side of a piece of paper (an impression on the other side of the piece of paper counting as a second impression). A count of total impressions made is, for example, a grand total of impressions made during a particular print job.
[0029] Other parameters types that may be included in a parameter or aspect list include a set completion flag, a set count, a diagnostic impression flag, a media descriptor, a highlight color flag and a full color flag. A set is some logical grouping of document pages. For example, a set is a collection of document pages on which a finishing step is performed. For instance, a set is a group of pages that are stapled together. Alternatively, a set is, for example, a collection of stapled documents that are shrink-wrapped together. A set completion flag indicates the completion of a set. Alternatively, a set completion flag indicates the completion of a number of sets. For example, a set completion flag may indicate the completion of ten or one hundred sets. A set count is, for example a running total of completed sets. Alternatively a set count is a grand total of sets completed in a job. A diagnostic impression flag indicates, for example, that an impression is a diagnostic impression, ordered, for example, by a service technician. In some cases, customers are not charged for diagnostic impressions. A diagnostic set flag may be used to indicate that a set is being run for diagnostic purposes. A media descriptor indicates, for example, the kind of media an impression is made on. For example, a media descriptor indicates that large paper is used or that a sheet of velum is marked or that regular paper is being printed on. A highlight color flag indicates when highlight color is included in an impression. A full color flag indicates when an impression includes full color markings. This list is exemplary only, and not intended to be limiting. Indeed, an important aspect of the billing module 130 is that the billing module 130 is readily adapted to record and use information regarding billable aspects of document processing that have not as yet been conceived.
[0030] A communications protocol may be implicit in the architecture of the billing module 130 . For example, it may be understood that each parameter or aspect in a parameter list will be communicated to the billing module in, for example, an eight-bit word. However, preferably, the format that the parameters are communicated to the billing module in is included in the parameter list. For example, a parameter or aspect list includes a first flag that is one bit long, a first count that is sixteen bits long, a second count that is eight bits long and a second flag that is one bit long. Having the data format passed to the billing module 130 by the marker is preferable because it provides for increased universality, especially with regard to as yet undeveloped markers and print engines.
[0031] The meter description 218 portion of the strategy specification 210 is also arbitrarily long and contains, for example, meter descriptions M 1 through Mn. In general, the meter descriptions are expressed in the form of functions f( ) of the parameters P 1 through Pn. The meter descriptions 218 explain what the billing module 130 is to do with parameter or aspect information passed to it. For example, the billing module 130 is instructed to maintain a first meter M 1 . An equation or function describes the operation of the first meter. For, example first expression 222 :
M 1 =M 1 +P 5
[0032] describes the function of the first meter M 1 . For instance, parameter P 5 is an impression count. Parameter P 5 reports the number of impressions made in a set upon the completion of the set. Therefore, when updated, the first meter M 1 records a total number of impressions made. The updated value of the first meter M 1 is the old value contained in the first meter M 1 plus the number of impressions P 5 made in the set.
[0033] Additionally, the billing module is instructed to maintain a second meter M 2 . The second meter M 2 is defined by a second expression 226 :
M 2 =M 2 +(P 5 *P 6 )
[0034] Parameter P 6 is a diagnostic flag. For example, parameter P 6 is one bit long and therefore has a value of zero or one. When parameter P 6 has a value of zero, the second expression 226 or meter M 2 operates to maintain the value of the second meter M 2 . That is to say, the new value of the second meter M 2 is equal to the old value of the second meter M 2 (M 2 =M 2 ). When the diagnostic flag P 6 has a value of one, the second meter M 2 operates to add the number of impressions made during the creation of a set, to the old total number of impressions (M 2 =M 2 +P 5 ).
[0035] The meter list section 218 of the first strategy specification 210 also operates to instruct the billing module 130 to keep track of discounted impressions with a third expression 230 :
M 3 =M 3 +(P 4 −500)*(P 4 >500 ?0:1)
[0036] Parameter P 4 is, for example, a set count. The set count is a running total of the number of sets completed during a job. When the inequality (P 4 >500) within the third expression is false, the right hand parenthetical expression (P 4 >500 ?0:1) has a value of zero. When the inequality is true the right hand parenthetical expression of the third expression 230 has a value of 1. Therefore, while parameter P 4 is not greater than five hundred, the third meter M 3 or expression 230 operates to maintain the value of the third meter (M 3 =M 3 ). When the set count P 4 in a job exceeds five hundred, the third meter M 3 or operates to tally the number of sets in the job, beyond the five hundredth set (M 3 =M 3 +(P 4 −500)).
[0037] Preferably, the meters described in the meter list 218 are implemented as virtual meters comprising memory locations that are written and read from as required. However, real meters can also be used. Where real meters are used, the billing module controls signaling hardware that increments or updates the meters as required. Of course, the values in virtual meters are read and displayed or communicated to other devices as desired.
[0038] As can be seen from the above description, a system developer can implement the billing portion of an image processor by including a copy of the universal billing module 130 in the system or by providing communications means between the system and a billing module 130 . The only other significant development work required is the creation of a billing strategy. The billing strategy may be hard coded and stored along with the system software or it maybe stored separately and accessed when needed. For example the strategy maybe stored as a file on a disk. Preferably, the strategy is secured by some protection technology such as password protection and/or encryption. Typically, a billing strategy is delivered to a billing module when a document processing system is first commissioned. Additionally, an updated strategy is delivered to a billing module when the document processing system is reconfigured. Alternatively, a billing strategy is delivered to a billing module at every system power up. Additionally, billing strategies may be delivered or updated remotely. For example, an image processor is connected to a computer network or includes a telephone modem. A billing strategy is downloaded to the image processor over these computer communication links.
[0039] To further illustrate this, FIG. 3 is a block diagram of a second document processing system 310 . The second document processing system comprises a controller 314 and an B-type print engine 318 . For example, the B-type print engine 318 is a XEROX DocuColor 2060 xerographic print engine. The controller 314 comprises hardware and software modules 322 operative to control and operate the document processing system 310 . The modules are in communication with sensors 324 directly or indirectly. For example, the document processing system 310 may contain sensors 324 . The sensors 324 can be real sensors distributed throughout the B-type print engine 318 and/or virtual sensors, distributed throughout software modules of the B-type print engine 318 (not shown) and/or controller 314 . The modules 322 include a B-type marker 326 module. The B-Type marker is a module specifically designed for controlling and taking advantage of the features and capabilities of B-Type print engines. For example, the B-type marker 326 module is a Xerox DocuColor 2060 marker, designed to control and take advantage of features of a XEROX DocuColor 2060 print engine. The B-type marker 326 is in communication with a copy of the universal billing module 130 . Just as described in reference to FIG. 1, the billing module 130 is part of the controller or the billing module 130 is separate from the document processing system 310 and simply in communication with the document processing system 310 .
[0040] The billing module 130 of FIG. 3 is an identical copy of the billing module 130 of FIG. 1, and therefore, carries the same reference numeral. The billing module 130 is configured by the B-type marker 326 to record billing information in a manner that is convenient and complementary to the features and architecture of the B-type marker 326 and the B-type print engine 318 . For example, the billing module 130 receives a strategy description from the B-type marker 326 (or from some other device, such as for example, a file (not shown).
[0041] Referring to FIG. 4, a B-type strategy 410 may be different than the A-type strategy 210 . For example, the B-type strategy 410 comprises a list of parameters 414 or aspects of interest and a list 418 of meter descriptions that are different than the parameter list 214 and meter list 218 of the first or A-type strategy 210 . The parameter list 414 informs the billing module 130 of the billable events or activities the B-type marker module 326 is capable of performing. Furthermore, the parameter list 414 explains the format in which the B-type marker 326 will communicate the parameters to the billing module 130 .
[0042] The meter description 418 portion of the B-type strategy specification 410 explains what the billing module 130 is to do with the parameter or aspect information passed to it. For example, the billing module 130 is instructed to maintain a first meter M 1 . In the second document processing system 310 , the processor keeps a running total of the number of impressions the processor makes. For example, hardware or software counters in the print engine keep track of the number of impressions. That total is passed to the billing module in a first parameter P 1 . The first meter M 1 is configured to keep track of the total number of impressions the document processing system makes by simply updating M 1 with the running total kept by the document processing system 310 . For example, meter M 1 of the second document processing system 310 is described by a first expression 422 :
M 1 =P 1
[0043] The B-type marker 326 also instructs the billing module 130 to keep track of the number of “3-pitch” sheets that are processed. A pitch is related to a sequence of events that comprise, for example, a xerographic printing process. For example, the sequence of steps required to infuse a sheet with one color toner can be classified a pitch. A 3-pitch sheet is a sheet that is processed through a basic sequence of steps three times. For example, a sheet longer than 9 inches is a 3-pitch sheet. An instruction to the billing module 130 to keep track of the number or 3-pitch sheets is, for example, found in a second expression 426 :
M 2 =P 2 *100
[0044] wherein P 2 reflects a marker 326 count of every hundredth 3-pitch sheet.
[0045] The information delivered to the billing module originates from sensors 124 , 324 distributed throughout a document processing system. The sensors can be real sensors or virtual sensors. Real sensors are physical in nature and sense physical events. For example, an optical sensor reports the transfer of a sheet from a supply tray. A limit switch notes the passing of a sheet past a transfer point. A virtual sensor is embodied in software and notes the occurrence of a logical event. A virtual sensor can be active or passive. An active virtual sensor scans part of the system, for example, the active virtual sensor examines a memory or register location and tests to see if values stored there match an anticipated value. The active virtual sensor then reports whether or not a match is found. A passive virtual sensor is usually embodied as a memory or register location. System software reports system activity by writing status information to the passive virtual sensor. Software then reads information from the passive virtual sensor at an appropriate point in, for example, a document processing procedure. For example, the print engine reads a passive sensor and reports its output to the marker, which in turn reports the passive sensor output to a billing module 130 . Alternatively, a billing module 130 reads the passive sensor directly.
[0046] Preferably, information reaches a billing module 130 as described, through services of a single software module, such as, for example a marker 126 , 326 . However, other architectures are possible. For example, networked system components may report information directly to the billing module 130 . A networked output tray sensor may report the completion of a sheet or the completion of a set directly to a billing module 130 . In such an architecture, the billing module may receive the billing strategy from one of the networked components, for example, a networked controller module. The billing strategy may further include, for example, a sensor introduction section, explaining the type and communication mechanism of various system sensors. Production event or aspect information is then delivered directly from the sensors (real and virtual) directly to the billing module via a network.
[0047] Billing information is, of course, sensitive by nature. Therefore, security measures can be included in the billing module and related systems. For example, the billing strategy is stored in an encrypted form. Access to the billing strategy is restricted. For example, a password is required to update or gain access to the billing strategy. Likewise, meters maintained by the billing module are protected against tampering. For example, virtual meter data is encrypted and stored in a non-volatile storage medium.
[0048] Referring to FIG. 5, a method 510 for developing and using a universal billing module comprises a billing strategy predefinition step 520 . As described in reference to FIG. 2 and FIG. 4, a billing strategy includes a parameter list with implicit or explicit communication mechanisms and data parsing information. Additionally, the billing strategy includes processing algorithm information in the form of, for example, a machine-readable script. In a billing strategy-reading step 530 , the billing strategy is read, for example, by a billing module. The billing strategy is decoded and followed. In a billing meter creation step 540 , memory is allocated for the storage of “meter” type data structures and the meters are initialized or “zeroed out”. Of course, the billing meter creation step 540 is only carried out when a required meter does not already exist. In many cases meters are instantiated in non-volatile memory and persist even when the image processor is turned off. Typically, where a meter already exists, the meter is not initialized or zeroed out. In a process-monitoring step 550 , the universal billing module monitors document processing system operation. In a meter-updating step 560 the meters are updated, based on the monitored operations, as instructed by the billing strategy machine-readable script.
[0049] The invention has been described with reference to particular embodiments. Modifications and alterations will occur to others upon reading and understanding this specification. For example, while the invention has been describe in relations to a billing module in a document processing system the method for developing and using reusable code can be applied to the development and use of any functional block or module. Furthermore, the universal billing module 130 can be applied to any machine that renders a product or service. When the invention is applied to document processing system applications, the document processing systems need not include print engines or marking modules. For example, a stand alone finishing devices such as, for example, collators, staplers, and shrink wrappers can take advantage of the universal billing module 130 . It is intended that all such modifications and alterations are included insofar as they come within the scope of the appended claims or equivalents thereof. | A billing module for a document processing system is configured by the document processing system. The billing module accepts a billing strategy from the document processing system. The billing strategy lists parameters or events the billing module is to monitor. Additionally the billing strategy provides algorithms. The algorithms define the function of billing meters. The billing module instantiates meters according to the strategy and updates the meters based on the monitored parameters as described by the billing strategy. The billing module is used by a wide variety of devices. Device developers need only define the billing strategy, in for example a billing strategy script. The need to “hard code” custom billing software for each new device is eliminated. Instead the billing module is reused and simply reconfigured via the billing strategy script. | 6 |
This is a continuation divisional of co-pending application Ser. No. 07/366,644 filed on June 15, 1989 now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the bottled water industry and more particularly to a sheeled dolly/hand truck for transporting large five-gallon plastic jugs of bottled water.
2. General Background
There are a number of commercially available sources of drinking water typically spring water contained in plastic reusable bottles. The most common of these reusable plastic bottles is a standard five-gallon plastic jug having a narrow mouth and a flat bottom portion. Typically these five-gallon jugs having two or more annular rims extending outwardly from the bottle side wall to facilitate a carrying of the jugs and to provide rolling surfaces when the jugs are rolled on their sides. Such five-gallon bottled water containers are commercially available from a number of sources and are typically returned by the user when the water has been consumed therefrom. One example of a five-gallon spring water container is the subject of Design Patent D-270,136. Such bottles are manufactured by Liquie-Box of Worthington, Ohio.
A number of coolers/dispensers are commercially available for use in dispensing bottled water from such five-gallon bottled water containers. One of the most common types of commercially available bottled water dispensers is an inverted bottle type construction wherein the bottle is turned upside down into an open receptacle or well which is on the top of the cooler dispenser. The bottle must be lifted approximately four feet, turned upside down, placed into the well for use. Water is thereafter dispensed from the cooler dispenser by depressing dispensing buttons upon spigots which extend forwardly of the cabinet of the cooler/dispenser.
Such five-gallon bottled water containers are heavy weighing approximately fifty pounds each. A problem exists in that these bottled water dispensers are typically delivered to the home or to offices in multiples of, for example, two to five bottles at a time. This produces wear and tear upon delivery personnel that must remove these bottles from trucks, often a substantial distance from the home, office buildings, businesses, and the like. Thus, there is a need for a bottle water carrier which can easily and safely transport multiple bottles of large five-gallon bottled water containers.
Another problem with the use of five-gallon containers is the weight associated with these containers even when handled one at a time by the consumer. For example, older people and handicapped people are typically required to pay for bottled water in much smaller capacities because of the weight associated with the more economical five-gallon containers. This unfairly punishes older and handicapped people because typically bottled water costs much more when purchased in small quantities of, for example, one half-gallon or one gallon.
Thus, there is a need for a simple, easy to use, easy to construct carrier for bottled water when such water is contained in large bottles of five gallons the most economical commercially available version of bottled water in this country.
SUMMARY OF THE PRESENT INVENTION
The present invention solves these prior art problems and shortcomings in a simple, straightforward fashion by providing a bottled water carrier for transporting bottles of water each having a capacity of, on the order of, five gallons. The apparatus includes an elongated frame having at its lower end portion an axle to which are mounted a pair of spaced-apart wheels positioned generally on opposite sides of the lower end of the frame. The upper end portion of the frame has a handle with a gripping surface thereon and at least two pair of arms extend forwardly of the frame during use, generally away from the user, the arms defining load carrying portions for transferring load from the bottle to the frame. In one version, a single bottle carrier is provided which can lift and transport the bottle. The single bottle carrier is of greatest utility to the homeowner, especially the aged, handicapped and/or less than powerful people. A second version in the form of a multiple bottle carrier is provided primarily for use by delivery personnel carrying two, three, four or five bottles at a time.
BRIEF DESCRIPTION OF THE DRAWINGS
For a further understanding of the nature, objects, and advantages of the present invention, reference should be had to the following detailed description, taken in conjunction with the accompanying drawings, in which like reference numerals denote like elements, and wherein:
FIG. 1 is a side view of a first embodiment of the apparatus of the present invention as shown during pickup of a bottled water container;
FIG. 2 is a side view of the first embodiment of the apparatus of the present invention shown during transport of the bottled water container after pickup engages the bottle with the frame;
FIG. 3 is front view of the first embodiment of the apparatus of the present invention;
FIG. 4 is a side view of the first embodiment of the apparatus of the present invention;
FIG. 5 is a top view of the first embodiment of the apparatus of the present invention;
FIG. 6 is a side view of a second embodiment of the apparatus of the present invention in the form of a multiple bottle water carrier;
FIG. 7 is a front view of the bottle water carrier of FIG. 6;
FIG. 8 is a side fragmentary view of the bottle water carrier of FIG. 6 illustrating a dispensing position for removing the bottles during unloading thereof; and
FIG. 9 is a fragmentary view of a second embodiment of the apparatus of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIGS. 1-5 there can be seen a first embodiment of the apparatus of the present invention in the form a single bottled water carrier designated generally by the numeral 10. The apparatus includes an elongated frame 12 having a lower end portion of the frame 12 carrying an axle 13 with the preferred construction including left and right axles 13A, 13B, each mounted upon gussets 12A, 12B respectively. Each axle carries a wheel 14, 15 at the lower end portion of frame 12. The upper end portion of frame 12 includes rearwardly curving portion 12C defining a concave portion 12D of the frame 12. A handle 16 is mounted upon portion 12C with a gripping surface 17 thereon so that a user, delivery person, or the like can grip the surface 17 and push the frame 12 carrying a bottle B therewith during transportation.
At least two pair of arms 20, 21 are provided including upper pair of arms which include left and right arms 20A, 20B. Rubber end caps 22 can be placed respectively on each arm 20A, 20B so that the end caps 22 help grip the bottle B during lifting, as shown in FIG. 1. The bottle B of water typically would be in a large capacity bottle B having a capacity of, on the order of, five gallons. An example of such a bottle is disclosed in Design Patent D-270,136 incorporated herein by reference. Such bottles B are commonly used for transporting and dispensing bottled spring water, for example, and they typically include a bottom 30 which is generally flat, a narrow mouth 31, and one or more annular ribs 32-34 which aid in lifting the bottle B and also define surfaces for rolling bottle B thereon, such as during handling at bottling plants and the like.
The frame 12 includes a generally U-shaped vertically upstanding portion 35 which forms a connection with each pair of arms or appendages 20, 21. The lower pair of arms 21 includes arms 21A, 21B. Each arm 21A, 21B includes a downwardly and forwardly extending foot 36, 37 which in combination with wheels 14, 15 defines a four-point support base so that the apparatus 10 is self-supporting in a generally vertical position, as shown in FIG. 1. The feet 36, 37 also define a forwardly inclined position which is typically assumed prior to the lifting of a bottle B, as shown in FIG. 1. The arms 20, 21 can be so positioned upon frame 12 that the arms 20, 21 register just below one or more of the annular ribs 32-34 so that a lifting up of the arms 20, 21 by rotating the frame 12 rearwardly (as shown by arrows in FIG. 2) causes each pair of arms 20, 21 to register upon one of the ribs 32-34 to aid in the lifting of bottle B. In the embodiments of FIGS. 1-5, the upper pair of arms 20 register slightly below the annular rib 32 when the frame 12 is rotated rearwardly as illustrated by the arrow 40 in FIG. 2. Further rotation of the frame 12 about axles 13A 13B in the direction of arrow 40 lifts bottle B free of the floor, so that transport can commence. The handle 16 can be rotated all the way to the floor with arms 20, 21 extending upwardly to support bottle B horizontally such as prior to placement on a cooler/dispenser.
In the embodiment of FIGS. 6-9, a multiple bottle B carrier is disclosed designated generally by the numeral 100. In the multiple bottled water carrier 100, there can be seen an elongated frame 101 having upper 102 and lower 103 end portions. The frame includes a pair of spaced-apart generally vertical stringer members 104, 105 each being curved and producing by such curvature a concave surface 106 which faces the user during use. Typically, the user would stand on the opposite side of members 104, 105 from a plurality of forwardly extending pairs of arms 107-110. As can best be seen in FIG. 9 (illustrated with pair 110), each pair of arms 107-110 includes left and right arms 107A-107B, 108A-108B, 109A-109B, 110A-110B which are connected at their rear most portion by U-shaped members 111-114 respectively. Each U-shaped member 111-114 carries respectively at its center portion a generally upstanding stop member 115-118 (FIG. 7). The arms 110A-110B are spaced less than the diameter of the bottle B.
The apparatus 100 of the embodiment of FIGS. 6-9 can be supported vertically as a self-standing stable structure even when loaded with bottles, resting upon its pair of wheels 119-120 and upon a pair of forwardly extending spaced-apart feet 121-122. The frame 101 can also be horizontally supported (FIG. 8).
During use, the user simply grips the frame 101 at its uppermost 102 end portion which defines a gripping surface 102A for grasping by a user. The user stands facing the concave 106 portion of frame 101 with the generally U-shaped portions 107-110 extending away from the user. The user can then leave the apparatus 10 in an upstanding position resting upon the combination of its wheels 119, 120 and its feet 121, 122, as shown in FIG. 6.
When unloading bottles B, as indicated by the arrow 125 in FIG. 8, the user can simply grip surface 102 and lower it downwardly so that the frame 101 eventually assumes a generally horizontal position of the elongated side members 104, 105. This position is shown in FIG. 8 wherein the supporting is by means of wheels 119, 120 and handle 102A. The arrow 125 illustrates removal of bottle B such as during an unloading for delivery. The apparatus 100 of the present invention securely holds multiple bottles B, each being on the order of, for example, five gallons of capacity, during transportation, during unloading, or during a stationary position (either horizontal or vertical) wherein the bottles are at rest such as when the delivery person is speaking with a customer, taking an order, delivering an invoice, or the like. This flexibility enables the delivery person to leave the frame in a vertical position unless unloading, eliminating substantial back breaking work in leaning over and lifting or lowering the frame when not necessary.
The present invention provides a very stable system for carrying multiple bottles which is an improvement over the common hand truck or rolling wagon in that it securely holds the bottles notwithstanding the position of the frame, be it in a generally vertical or in a generally horizontal position. The curved configuration of the frame 101 provides a very even balance of load, allowing the user to position bottles both forwardly and rearwardly of the wheel base during transportation so that the weight is very evenly distributed with respect to the wheels. The user can simply rotate the frame 101 forwardly or backwardly upon the wheel base until he "feels" a neutral balance as the bottles balance each other on opposite sides of the axles. Only the forward load component must be overcome, namely, overcoming rolling frictional resistance. There is little or no lifting required by the operator with regard to any vertical load component of the weight of the bottles during transport. These vertical bottle load components are cancelled because of the forward and aft positioning of the bottles during transport and thus a balancing of the load.
In view of the numerous modifications which could be made to the preferred embodiments disclosed herein without departing from the scope or spirit of the present invention, the details herein are to be interpreted as illustrative and not in a limiting sense. | A wheeled transporting device for use in carrying large five-gallon bottled water containers uses an improved frame configuration that cradles one or more of the bottles between appendages that extend outwardly, horizontally of the frame when the frame is vertically positioned. | 1 |
FIELD OF THE INVENTION
The present invention is directed to the field of remote enclosures for electrical equipment, and more particularly to an anchor frame for mounting a remote enclosure, such as a remote Digital Loop Carrier (DLC) or Private Branch Exchange (PBX), to the ground.
BACKGROUND OF THE INVENTION
When installing telecommunications networks, it is often necessary to place multiplexing equipment, PBX's, DLC's, and other network equipment in remote locations separate from any building structure. Remote enclosures are usually made of metal and anchored either directly to the ground or to a concrete pad.
Anchoring the remote enclosure to a concrete pad provides greater stability than anchoring the enclosure into the ground, however, concrete anchoring requires more time, effort and cost.
Conventional approaches to anchoring remote PBX enclosures onto concrete pads include setting anchor bolts into the wet concrete. To hold the bolts in the wet concrete, a temporary jig can be made to extend over the concrete and suspend anchor bolts into the area where the concrete is poured. When the concrete dries, the jig is removed and the bolts extend out of the concrete pad. The remote enclosure is then mounted onto the anchor bolts. This approach is time consuming and prone to dimensional errors, as the lower ends of the anchor bolts tend to shift when the concrete is poured.
Other approaches use metal frames which are made of angular or tubular metal pieces welded together. These frames are expensive and require labor intensive fabrication.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a cost effective anchor frame for a remote enclosure which can be easily fabricated and installed, and can be used to facilitate the process of installing remote enclosures onto concrete pads.
It is another object of the present invention to provide a low cost anchor frame which accurately holds anchor bolts while concrete is poured to surround the bolts, so that the bolts later extend out of the dried concrete pad in the proper location where a remote enclosure can receive the bolts.
It is another object of the present invention to provide a low cost anchor frame which guides cables and wires through a concrete pad and into the bottom of a remote enclosure.
These and other objects of the present invention can be realized by providing a unibody anchor frame with preformed wire guide holes and anchor bolt holes which accurately holds the bolts and wires in place while concrete is poured to surround the anchor frame and form the pad.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be more clearly understood from the following description in conjunction with the accompanying drawings, wherein:
FIG. 1 is a perspective view of an embodiment of an anchor frame according present invention;
FIG. 2 is a perspective view of an anchor frame and installation accessories according to the present invention;
FIG. 3 is side view of an anchor frame and jig according to the present invention; and
FIG. 4 is a side cutaway view of an installed anchor frame according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
An embodiment of an anchor frame according to the present invention is shown in FIG. 1. In this embodiment, the anchor frame 1 is one sheet-metal piece with preformed or stamped cable holes 8 in the floor 12 so that buried cables and wires 13 can be fed from the ground through the frame 1 (FIG. 4), and into a remote enclosure (not shown). The edges 9 of the anchor frame 1 are folded upward and have tabs 10 which extend from the edges 9 to be substantially parallel to the floor 12. Anchor holes 11a and 11b are formed in the tabs 10 and floor 12, respectively, so that anchor bolts 2 can pass through. The tabs 10 with holes 11a provide an easily fabricated additional measure of stability, and help keep the bolts 2 straight, especially when concrete is being poured. For ease in installation and increased stability in concrete, L-shaped anchor bolts 2 are used.
The frame 1 is preferably electro-galvanized steel while the anchor bolts 2 are made of stainless steel. The dimensions of the anchor frame 1 should approximate the footprint of the remote enclosure to be installed.
Anchor holes 11a and/or 11b should create a snug fit with the anchor bolts 2. This will ensure accurate placement and direction of the portion of the bolts 2 which extends from the concrete pad 7. While threaded holes may be used, manufacturing can be simplified by using D-shaped anchor holes 11a for threading the anchor bolt. Additionally or alternatively, anchor holes 11b could be D-shaped.
As shown in FIGS. 2 and 3, the present invention can simplify installation of a remote enclosure onto a concrete pad according to the following steps. Pad size and construction methods may vary to comply with local conditions, practices, or building codes.
1. Prior to pad construction, any ground rods, ground wires, conduit, and cabling should be installed. The conduit and ground wire should be laid in a trench roughly 2 feet deep. A hole should be dug where the concrete is to be poured and the conduit, ground rod, and ground wire should exit the ground through the hole.
2. As shown in FIG. 1, the anchor frame 1 can be shipped with protective plastic caps to be placed over the threaded anchor bolts 2. The anchor frame 1 is first assembled by threading the four L-shaped threaded anchor bolts 2 through the holes 11a and 11b. The shorter length of the L-shape should be at the bottom.
3. As shown in FIGS. 2 and 3, a jig 5 can be built to hold the anchor frame 1 in place when pouring the cement. Care should be exercised not to cover the conduit openings in the anchor frame 1 with the jig 5. The jig 5 should embed the anchor frame 1 in the cement allowing a sufficient length of the threads to extend above the cement surface (see FIG. 4).
4. After building the jig 5, the plastic bar guards 3 should be removed from the anchor bolts 2 and the anchor frame 1 can be secured to the jig 5 via hex nuts 4. Prior laid wire and/or conduit is then routed through the appropriate openings 8 in the frame (FIGS. 1 and 4). The conduit should extend approximately 2 inches above the cement surface to prevent poured cement from entering the opening.
5. Cement is then poured, and the pad surface is crowned in such a way to provide run-off for water and maintain a level mounting surface for the REX. Crowning will ensure that water does not pool on the top surface of the pad.
6. Once the cement dries, the forms 6 and jig 5 can be removed, and the plastic bar guards 3 can be reinstalled over the anchor bolts 2 until the installer is ready to install the enclosure.
The present invention was developed in conjunction with remote housings to provide additional deployment opportunities, and its development has made a significant contribution to the saleability of these remote housings. While the anchor frame 1 was designed specifically to accommodate a REX housing, it could be modified for use with other housings, such as T-REX housings.
The present invention provides significant advantages over previous anchor frames. For example, fabrication costs are minimized due to a low part count, ease of assembly, low material costs, and minimal labor requirements. In additions, the present invention reduces installation time and costs while improving dimensional accuracy.
As specific embodiments of the invention have been described herein, it will be apparent to those of skill in the art that other modifications may be made within the scope of the invention, and it is intended that the full measure of the invention be determined with reference to the following claims. | An anchor frame for securely fastening a remote housing to a concrete pad, formed from one piece of sheet-metal to hold anchor bolts and wires in place when pouring a concrete pad for a remote enclosure, so that the bolts are properly aligned for attaching to the remote enclosure. The anchor frame speeds construction of concrete mounting pads for remote enclosures. | 4 |
TECHNICAL FIELD
[0001] The present invention relates generally to a process of manufacturing nonwoven fabrics, and in particular, a process that incorporates a reversible thermochromic pigment into a polymer melt in order to achieve a durable and uniform distribution of thermochromic characteristics within a spunmelt nonwoven fabric.
BACKGROUND OF THE INVENTION
[0002] Reversible thermochromic chemistry allows for materials which are capable of changing from a first color to a second color in the presence of heat. Such substances have previously been used in combination with nonwoven and woven fabrics. Woven fabrics are those fabrics comprised of a plurality of warp and weft yarns that are interlaced on a loom. Nonwoven fabrics are comprised of natural or synthetic fiber, or a combination thereof, which are formed into a web or batt and then bonded or interlocked by means commonly known to one skilled in the art.
[0003] Nonwoven fabrics are highly versatile as they can be altered functionally and aesthetically, by use of suitable additives, to meet the needs of a multitude of end products, such as in apparel, industrial, and hygiene products. Reversible thermochromic pigment is one such additive that can change the appearance of a nonwoven fabric, and is generally useful in that such pigments are indicators of thermal history or attainment of temperature. By incorporating a thermochromic pigment onto a nonwoven fabric, the fabric provides a visual indication of a shift in temperature of the fabric through color change. A nonwoven fabric comprising a reversible thermochromic pigment will change colors with the temperature flux, meaning it can go back and forth between two colors depending on the degree of heat directed toward the fabric.
[0004] As evident in the prior art, thermochromic materials have been used in combination with nonwoven fabrics, as demonstrated by U.S. Pat. Nos. 6,228,804; 5,252,103; and 4,681,791, all hereby incorporated by reference.
[0005] U.S. Pat. No. 6,228,804 describes a color-change material comprising a reversible thermochromic layer that is superimposed onto a porous layer, wherein the porous layer includes a low-refractive-index pigment. The microencapsulated thermochromic material is dispersed into a film-forming compound containing a binder and applied to a substrate, such as a nonwoven.
[0006] U.S. Pat. No. 5,252,103 teaches a method of pigmenting fibrous cellulosic material that can be a nonwoven fabric, in which the material is initially treated with a cationic compound and then immersed in an aqueous solution of an anionic compound and a pigment. A thermochromic substance may be added to said aqueous solution in order to give color-changing properties to the pigmented fabric and a binder may be added to the solution to enhance fabric durability.
[0007] U.S. Pat. No. 4,681,791 discloses a method of forming a reversible thermochromic nonwoven fabric by means of coating the individual fibers prior to forming the fabric. The individual fibers are coated with thermochromic pigment and a binder mixture whereby the resultant fabric is believed to have better thermochromic uniformity.
[0008] As indicated above, the prior art encompasses multi-stepped processes to achieve a thermochromic nonwoven. The durability of the thermochromic pigment, however, is deleteriously affected due to the topical application of the pigment onto the fabric. Topical application of the thermochromic pigment can lead to color flaws in the fabric's surface if the fabric is subjected to abrasion or the coating is not uniformly applied. The prior art clearly warrants a need for a more efficient mode of acquiring a durable thermochromic nonwoven fabric. The present invention discloses a rapid method of fabricating a uniform and durable, reversibly thermochromic nonwoven fabric.
SUMMARY OF THE INVENTION
[0009] The present invention relates to a method of achieving a uniform distribution of reversible thermochromic pigment within a spunmelt nonwoven fabric, by incorporating the reversible thermochromic pigment into the polymer melt at the time of fiber or filament formation. It has been found that incorporating the pigment into the polymer melt enhances thermochromic uniformity as well as fabric durability. In addition, the reversible thermochromic fabric is processed in a single formation step, resulting in the present invention being more efficient than those methods practiced in the prior art.
[0010] Prior art suggests the use of a binder to assist with the adhesion of the reversible thermochromic pigment to the fiber, with the intention of enhancing the color fastness of the fabric. The present invention does not require a binder to either adhere the thermochromic pigment to the nonwoven fabric or for the purpose of color durability enhancement. By integrating the reversible thermochromic pigment into the polymeric melt, the pigment is incorporated throughout the extruded filaments, forming a uniform reversible thermochromic fabric and a fabric resistant to surface color defects that may be caused by abrasion or washing of the nonwoven fabric.
[0011] Reversible thermochromic pigments function under a Lewis acid chemistry. At a specific temperature, electron donation occurs resulting in a shift of wavelength absorption properties that causes a color change. The reversible thermochromic pigment particles utilized in the present invention consist of the standard color changing components that are disclosed in U.S. Pat. No. 4,681,791, hereby incorporated by reference. The reversible thermochromic pigment of the present invention also contains UV absorber chemistry in order to prevent thermochromic degradation in the presence of UV light. In the present invention, the manufacturing process time to produce a reversible thermochromic nonwoven is much shorter. The thermochromic concentrate is combined within a polymer melt blend creating a homogeneous mixture. The melt blend is extruded as the fibers or filaments are collected on a forminous screen forming a web. It is also within the purview of the present invention that the nonwoven fabric comprises staple length fibers. The web is then bonded to form a nonwoven fabric. The resultant nonwoven fabric is one that can alter its appearance by changing color in response to heat.
DETAILED DESCRIPTION OF THE INVENTION
[0012] While the present invention is susceptible of embodiment in various forms, hereinafter is described a presently preferred embodiment of the invention, with the understanding that the present disclosure is to be considered as an exemplification of the invention, and is not intended to limit the invention to the specific embodiment illustrated.
[0013] In accordance to the present invention, the nonwoven fabric is a spunmelt, as exemplified by meltblown fabrics or spunbond fabrics, and any combinations thereof. The fibers or filaments of the spunmelt can be selected from a group of polyesters, polyamides, or polyolefins, such as polypropylene, polyethylene, and the combinations thereof. The fibers or filaments may also be one of a multi-component configuration of the above mentioned polymers. The fibers may also be staple-length fibers wherein the molten polymer is extruded and drawn, resulting in a tow, which is cut into finite staple-lengths.
[0014] A spunbond process involves supplying a molten polymer, which is then extruded under pressure through a large number of orifices in a plate known as a spinneret or die. The resulting continuous filaments are quenched and drawn by any of a number of methods, such as slot draw systems, attenuator guns, or Godet rolls. The continuous filaments are collected as a loose web upon a moving foraminous surface, such as a wire mesh conveyor belt. When more than one spinneret is used in line for the purpose of forming a multi-layered fabric, the subsequent webs is collected upon the uppermost surface of the previously formed web. The web is then at least temporarily consolidated, usually by means involving heat and pressure, such as by thermal point bonding. Using this bonding means, the web or layers of webs are passed between two hot metal rolls, one of which has an embossed pattern to impart and achieve the desired degree of point bonding, usually on the order of 10 to 40 percent of the overall surface area being so bonded.
[0015] A related means to the spunbond process for forming a layer of a nonwoven fabric is the melt blown process. Again, a molten polymer is extruded under pressure through orifices in a spinneret or die. High velocity air impinges upon and entrains the filaments as they exit the die. The energy of this step is such that the formed filaments are greatly reduced in diameter and are fractured so that microfibers of finite length are produced. The extruded multiple and continuous filaments can be optionally imparted with a selected level of crimp, then cut into fibers of finite staple length. These thermoplastic resin staple fibers can then be subsequently used to form textile yarns or carded and integrated into nonwoven fabrics by appropriate means, as exemplified by thermobonding, adhesive bonding, and hydroentanglement technologies. The process to form either a single layer or a multiple-layer fabric is continuous, that is, the process steps are uninterrupted from extrusion of the filaments to form the first layer until the bonded web is wound into a roll.
[0016] The spunmelt nonwoven fabric of the present invention has a preferred basis weight range of 0.50-2.50 osy, with a most preferred basis weight range of 1.0-2.0 osy. Incorporated into the spunmelt polymeric melt of the nonwoven fabric is a reversible thermochromic pigment. In the present invention, the nonwoven fabric is lavender at room temperature, however the color of the fabric can be any one of an array of colors based on the thermochromic pigment used and is not meant to be a limiting factor of the present invention. The reversible thermochromic nonwoven fabric has a preferred temperature indicating range of 40° C.-60° C., with the most preferred temperature indicating range of 45° C.-55° C. The nonwoven fabric of the present invention changes from lavender to white when exposed to temperatures within the fabrics temperature indicating range. Once the temperature has risen above or below the temperature indicating range of the thermochromic nonwoven fabric, the fabric reverts back to the lavender color.
[0017] The reversible thermochromic pigment utilized in the present invention contains particles preferably 3-5 microns in size, with a most preferred particle size of 3 microns. The chemistry of the reversible thermochromic pigment is a conventional construct, consisting of an electron-donating color former, electron-accepting developer in which the compound contains a phenolic hydroxyl group, carboxylic acid with 2-5 carbon atoms or carboxylic salts, and a thermally controlled color-changing agent which can be an alcohol, ester, or ketone, to name a few. Such thermochromic pigments are available from Polymer Dynamix, including the reversible thermochromic pigment of the present invention, which is commercially known as TC-4555-PP. The thermochromic pigment is added to the polymer melt at a preferred range from about 0.5%-5%, having a more preferred range of 1%-5%, and a most preferred range of 2%-4%.
[0018] The polymeric melt may also contain additional additives such as UV absorbent chemistry in order to inhibit degradation of the electron-accepting developer in the presence of UV light. UV absorbent chemistries operate to transfer photochemical energy into thermal energy. Other additives that assist with product enhancements, such as static control, stain resistance, flame retardency, fluidic absorbency or repellency may also be utilized with the present invention. The reversible thermochromic pigment particles, which are incorporated into the polymeric melt, may also contain a coating, such as a wax, to assist with processing.
[0019] In one embodiment of the present invention, the spunmelt nonwoven fabric is a spunbond polypropylene with a basis weight of 1.50 osy and has a reversible temperature indicating range of 45° C.-55° C. The reversible thermochromic pigment was added at 3% by weight to the polymer melt. The resultant color-changing fabric can be useful in a variety of commercial applications such as bedding, apparel, and hygiene. | The present invention relates to a method of achieving a uniform distribution of reversible thermochromic pigment within a spunmelt nonwoven fabric, by incorporating the reversible thermochromic pigment into the polymer melt at the time of fiber or filament formation. It has been found that incorporating the pigment into the polymer melt enhances thermochromic uniformity as well as fabric durability. In addition, the reversible thermochromic fabric is processed in a single formation step, resulting in the present invention being more efficient than those methods practiced in the prior art. | 3 |
PRIORITY
[0001] The present application claims priority to U.S. Provisional Application No. 61/487,768 filed May 19, 2011; U.S. Provisional Application No. 61/587,866 filed Jan. 18, 2012; and U.S. Provisional Application No. 61/591,627 filed Jan. 27, 2012; the disclosures of which are incorporated herein by reference. The present application is also being co-filed with applications titled Child Car Seat (Applicant reference BTE-P0005-01) and titled Shoulder Belt Height Adjuster (Applicant reference BTE-P0005-03) the disclosures of which are incorporated herein by reference.
FIELD
[0002] The present disclosure relates to generally to a child car seat, and more particularly to a child car seat with an adjustment mechanism that allows simultaneous adjustment of back and headrest height.
BACKGROUND AND SUMMARY
[0003] Child car seats can often be bulky items that prove difficult and costly to transport. Additionally, as a child grows, differing styles of car seats are appropriate. Accordingly, the present disclosure provides a child car seat that is both compactable for transport and convertible from a style having a back portion to a booster style.
[0004] According to an embodiment of the present disclosure, a child car seat is provided including: a seat portion; a back portion adjustably coupled to the seat portion; a headrest adjustably coupled to the back portion; and an actuator, the actuator having a first position that locks the back portion relative to the seat portion and that locks the back portion relative to the headrest portion, the actuator having a second position that allows movement of the back portion relative to both the seat portion and the headrest portion.
[0005] According to another embodiment of the present disclosure, a child car seat is provided including: a seat portion; a back portion coupled to and vertically adjustable relative to the seat portion; a headrest coupled to and vertically adjustable relative to the back portion; and an actuator, the actuator having a first position that locks the back portion relative to the seat portion and that locks the back portion relative to the headrest portion, the actuator having a second position that allows movement of the back portion relative to both the seat portion and the headrest portion.
[0006] According to another embodiment of the present disclosure, a child car seat back portion is provided including: a seat coupler operable to couple the back portion to a seat portion of a child car seat; a back support coupled to and vertically adjustable relative to the seat coupler; a headrest coupled to and vertically adjustable relative to the back support; and an actuator, the actuator having a first position that locks the position of the back support relative to the seat coupler and that locks the back support relative to the headrest, the actuator having a second position that allows movement of the back support relative to both the seat coupler and the headrest.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The above-mentioned and other features of the disclosure, and the manner of attaining them, will become more apparent and the disclosure itself will be better understood by reference to the following description taken in conjunction with the accompanying drawings, wherein:
[0008] FIG. 1 a illustrates a child seat with a back portion attached and in a first orientation;
[0009] FIG. 1 b illustrates the child seat of FIG. 1 being used as a booster seat with a back;
[0010] FIG. 2 illustrates the child seat of FIG. 1 with the back portion removed;
[0011] FIG. 3 shows the child seat of FIG. 1 with the back portion attached and in a second position; and
[0012] FIG. 4 is a side cross-sectional view of the child seat of FIG. 1 ;
[0013] FIGS. 5 a & b are side cross-sectional and perspective views of the back portion of FIG. 1 , respectively;
[0014] FIG. 5 c is a plan view of the back portion of FIG. 1 ;
[0015] FIG. 5 d is a side cross-sectional view of the back portion of FIG. 1
[0016] FIGS. 6 a & b is a overhead perspective view of a portion of the child seat in the position of FIG. 3 with the upholstery removed;
[0017] FIG. 7 is an overhead perspective view of the child seat in the position of FIG. 1 with various parts removed to show additional detail and with the upholstery removed;
[0018] FIG. 8 is a perspective view of a riser apparatus of the child seat of FIG. 1 ;
[0019] FIG. 9 a - c are pictures of a belt tether used with the apparatus of FIG. 2 ;
[0020] FIGS. 10 a - e are pictures of the child seat of FIG. 1 with a head support portion at multiple settings;
[0021] FIGS. 11 a - c are pictures of inserts used in the child seat of FIG. 1 ;
[0022] FIGS. 12 a - b are perspective views of the base portion of the child seat of FIG. 1 ;
[0023] FIG. 13 is a front bottom perspective view of the base portion of the child seat of FIG. 1 ;
[0024] FIG. 14 is a back bottom perspective view of the base portion of the child seat of FIG. 1 ;
[0025] FIG. 15 is a top perspective view of a lower attachment mechanism of the child seat of FIG. 1 with portions removed;
[0026] FIG. 16 is a side perspective view of the lower attachment mechanism of the child seat of FIG. 1 with portions removed;
[0027] FIGS. 17 a - b are overhead and side plan views of the lower attachment mechanism of the child seat of FIG. 1 ; and
[0028] FIGS. 18 a - b are perspective views of the lower attachment mechanism of the child seat of FIG. 1 .
[0029] Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate exemplary embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.
DETAILED DESCRIPTION
[0030] The embodiments disclosed herein are not intended to be exhaustive or to limit the disclosure to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may utilize their teachings.
[0031] Referring to FIG. la, an exemplary child car seat 10 is shown. Car seat 10 generally includes a base portion 12 and a back portion 14 . Base portion 12 and back portion 14 are separable. FIG. 2 shows car seat 10 in use where back portion 14 is removed and only base portion 12 is being used. In addition to being separable, base portion 12 and back portion 14 have orientations that are hingedly connected. Fig. la shows seat 10 with back portion 14 locked in an upright position. FIG. 3 shows seat 10 with back portion 14 in a lowered position.
[0032] Back portion 14 , as shown in FIGS. 5 a & b includes head support portion 16 and lumbar support portion 18 . Head support portion 16 is adjustable and lockable relative to lumbar support portion 18 . Lumbar support portion 18 is further adjustable relative to base portion 12 . Head support portion 16 includes an adjustment mechanism 42 ( FIGS. 5 a & b ). Adjustment mechanism 42 includes a lock rod, 40 ( FIG. 5 d ), and a button (actuator) 46 mechanically coupled to lock rod 40 .
[0033] Button 46 includes a lower portion 47 that engages slides 44 ( FIG. 5 a ). Slides 44 are fixedly coupled to lock rod 40 . Button 46 further includes upper portion 49 that includes a front lock projections 52 . Front lock projections 52 are sized, shaped, and located to engage lock receivers 53 disposed on the rear of head support portion 16 .
[0034] Lock rod 40 ( FIG. 5 d ) is moveable through activation of button 46 . Lock rod 40 has a first position that corresponds with a first position of button 46 , in which lock rod 40 engages one of detents 48 in lock plate 50 of lumbar portion 18 .
[0035] The first position of button 46 locks the relative positioning of the head support portion 16 and the lumbar support portion 18 relative to each other and vertically relative to base portion 12 by placing lock rod 40 it its first position. The first position of button 46 also places front lock projections 52 within lock receivers 53 . A plurality of springs bias button 46 and lock rod 40 to the first position.
[0036] Lock rod 40 has a second position that corresponds with a second position of button 46 in which lock rod 40 is disengaged from detents 48 of lock plate 50 and front lock projections 52 disengage from lock receivers 53 . The second position allows adjustment of the height of head support portion 16 relative to lumbar support portion 18 and the adjustment of either or both head support portion 16 and lumbar support portion 18 relative to base portion 12 . Movement of button 46 between the first position and the second position involves pressing button 46 rearward such that it rotates about its upper end.
[0037] Harness voids 55 are disposed on either side of button 46 in lumbar support portion 18 . As lumbar support portion 18 is adjusted relative to base portion 12 , harness voids 55 are also adjusted. Accordingly, the height of harness voids 55 are adjustable without having to remove and re-thread belts.
[0038] FIGS. 10 a - e show head support portion 16 positioned at a plurality of heights. Head support portion 16 includes covering 200 . Covering 200 includes head support covering 216 and torso covering 218 . As shown by the varying heights in FIGS. 10 a - e , both head support covering 216 and torso covering 218 move with head support portion 16 .
[0039] Torso support covering 218 includes a central portion 220 , opposing upper side portions 222 , and opposing lower side portions 224 . Opposing upper side portions 222 are positioned rearwardly of head support portion 16 . Accordingly, any attempt to push side portions 222 , 224 inwardly causes upper side portions 222 to abut the rear side of head support portion 16 . Once upper side portions 222 are abutting the rear side of head support portion 16 , further inward motion imparted to upper side portions 222 causes upper side portions to flex. The flexing is provided as the lower sides of upper side portions 222 do not engage the back side of head support portion 16 . The flexing allows buildup of potential energy that urges upper side portions 222 outwardly.
[0040] Opposing lower side portions 224 include inner flexible supports 226 , FIGS. 11 a - c . When head support portion is in the highest position, FIG. 10 a , the lower end of opposing lower side portions 224 almost clear armrests 54 . Armrests 54 engage the lower ends of opposing lower side portions 224 to keep opposing lower side portions 224 between armrests 54 . As head support portion 16 is lowered, greater portions of opposing lower side portions 224 are below the height of armrests 54 . Accordingly, as head support portion 16 is lowered, greater portions of opposing lower side portions 224 are urged inwardly.
[0041] As previously noted, opposing upper side portions are restricted from moving inward. Lowering head support portion 16 urges opposing lower side portions 224 inward. Opposing upper 222 and lower side portions 224 are formed from a continuous piece of fabric. The opposing forces supplied by head support portion 16 and armrests 54 cause side portions 222 , 224 to flex.
[0042] Inner flexible supports 226 are sewn into opposing lower side portions 224 and include inner sides 234 , FIG. 11 a , and outer sides 232 , FIG. 11 b . Inner flexible supports 226 , on outer sides 232 , have a plurality of substantially horizontal voids 228 as well as curving generally vertical void 230 . Inner sides 234 of inner flexible supports 226 also have curving generally vertical void 236 that mirrors void 230 . Inner flexible supports 226 are illustratively made from expanded polypropylene. Expanded polypropylene is flexible, as will be discussed in more detail below. Voids 228 , 230 , 236 aid in allowing supports 226 to bend and flex when stressed by armrests 54 and head support 16 (via upper side portions 222 ).
[0043] As seen most clearly in FIGS. 10 a - e , lowering head support portion 16 also lowers covering 200 including head support covering 216 and torso covering 218 . As previously noted, a lower positioning of torso covering 218 causes greater position interference with armrests 54 . Thus, lower positioning of head support portion 16 provides an increased amount of lower side portions 224 between armrests 54 . An increased amount of lower side portions 224 between armrests 54 creates a smaller space between inner surfaces of opposing lower side portions 224 . Accordingly, a lower overall height is paired with a decreased width of the seating area. On average, a child for whom a lower height is appropriate would also find that a decreased width of the seating area is also appropriate. Thus, appropriate adjustment of the height of head support portion 16 also provides appropriate adjustment of the width of the seating area.
[0044] Lumbar support portion 18 includes lumbar housing 20 , fabric covering 21 , and a pair of support beams 22 . Lumbar housing 20 is primarily constructed of a hard plastic. Fabric covering covers lumbar housing 21 and also includes lateral pockets 23 ( FIG. 1 ). Lateral pockets 23 contain side impact supports. Side impact supports are plastic pieces designed to cushion and protect in the event that later forces are imparted on car seat 10 . When lumbar support portion 18 is raised relative to base portion 12 ( FIGS. 1 b , 5 d, 4 ) a greater portion of lateral pockets are clear of armrests 54 . Fabric covering 21 then pulls pockets 23 and side impact supports outward and rearward. When lumbar support portion 18 is lowered relative to base portion 12 ( FIGS. 5 b , 1 ) armrests 54 engage more of pockets 23 and urge them inward.
[0045] When lumbar support portion 18 is in the raised position, or otherwise, car seat 10 can also serve as a booster seat with a back ( FIG. 1 b ). In such a configuration, the harness belts can be removed and seatbelts from the car can be used. Head support portion 16 further includes belt retainer 19 to aid in this configuration.
[0046] Beams 22 are spaced laterally from each other and assume an “L” shape. Each beam includes a lumbar beam portion 24 fixedly coupled within lumbar housing 20 and a base beam portion 26 that extends out of a lower end 28 of lumbar housing 20 . Beams 22 also include an arced portion 30 in between lumbar beam portion 24 and base beam portion 26 . Arced portions 30 are curved such that a longitudinal axis 32 of lumbar beam portion 24 is approximately perpendicular to a longitudinal axis 34 of base beam portion 26 , FIG. 4 . Arced portions 30 have locks 74 attached thereto. Beams 22 are rectangular in cross section and define interior space 36 therein. Base ends 38 of base beam portions 26 are open and sized to receive rotatable connectors 78 of base portion 12 therein. When back portion 14 is attached to base portion 12 , rotatable connectors 78 of base portion 12 are each received in interior space 36 of respective base ends 38 of beams 22 . Rotatable connectors 78 are sized to snugly fit within interior space 36 of respective base ends 38 of beams 22 . Accordingly, when rotatable connectors 78 are within interior space 36 of base ends 38 , only pulling base beam portion 26 directly along longitudinal axis 34 of base beam portion 26 allows disengagement of rotatable connectors 78 from base beam portion 26 . Additionally, base ends 38 are connected to each other by cross brace 80 .
[0047] Base portion 12 includes right and left armrests 54 and a seat portion 56 between armrests 54 . Seat portion 56 includes front seat portion 58 and rear seat portion 60 . Front seat portion 58 includes a top surface 62 that includes a strap aperture 64 and a strap coupler/release (not shown). Strap aperture 64 receives a strap therethrough, that when pulled, tightens seat restraints (not shown). The strap coupler/release receives the strap such that when the strap is pulled, it is prevented from retracting back into base portion 12 . A user may depress the strap coupler/release to selectively allow the strap to retract into base portion 12 . Strap coupler/release is biased to the position that prevents strap retraction.
[0048] Front seat portion 58 also includes a bottom surface that includes riser apparatus 68 . Riser apparatus 68 , FIG. 8 , includes is a foot 66 that can be extended from below base portion 12 to alter the angle that base portion 12 assumes relative to the surface on which car seat 10 rests. Riser apparatus 68 further includes handle 116 , retainer bar 118 , and a pair of springs 120 . Foot 66 includes seat engaging portion 122 and legs 124 . Legs 124 are disposed at the lateral sides of seat engaging portion 122 and extend generally perpendicular thereto. Each leg 124 includes alignment spines 126 on fore and aft surfaces thereof and includes detent void 128 . Alignment spines 126 correspond and complement tracks defined in the lower surface of base portion 12 to define a movement track for foot 66 relative to base portion 12 . More specifically, spines 126 and the tracks in base portion 12 define a linear movement of foot 66 . Each detent void 128 includes four detents 129 sized to receive retainer bar 118 therein. Detents 129 are vertically aligned, which is consistent with the linear movement of foot 66 . Springs 120 have one end that engages retainer bar 118 and opposite ends that couple to projections on base portion 12 . Springs 120 thereby bias retainer bar 118 to a rearward position. The rearward position of retainer bar 118 fixes the relative position of foot 66 to base portion 12 . Handle 116 is coupled to retainer bar 118 such that movement of handle 116 causes movement of retainer bar 118 . Handle 116 is slidable relative to base portion 12 by virtue of being coupled to base portion 12 through slots 132 . Front edge 130 of handle 116 is graspable by a user. In that handle 116 is fixedly coupled to retainer bar 118 and that springs 120 bias retainer bar 118 rearward, handle 116 is likewise biased rearward. A user can pull front edge 130 to move handle 116 forward. Such forward movement results in forward movement of retainer bar 118 which allows movement of foot 66 relative to base portion 12 . When a user releases front edge 130 , springs 120 , through retainer bar 118 , pull handle 116 rearward and cause retainer bar 118 to engage a detent 129 . The position of foot 66 relative to base portion 12 is then again fixed.
[0049] In addition to allowing extension of foot 66 by activation of handle 116 , the rear surface of detent void 128 is angled between detents 129 . Accordingly, if a user places one hand on foot 66 and applies an upward force on base portion 12 (or a rearward force on head portion 16 ) the rear surface of detent void will allow legs 124 to lower and urge retainer bar 118 forward. Once legs 124 are low enough such that retainer bar 118 clears the next higher detent 129 , springs 120 pull retainer bar 118 into the next higher detent 129 . Thus, foot 66 can be extended by force. However, foot 66 can not be retracted by force due to the shape of detent void 128 .
[0050] Rear seat portion 60 includes tray 70 and connection support box 72 . Tray 70 , FIG. 7 , extends at a constant width and includes lock bar 76 , rotation bar 82 , rotatable connectors 78 , support grid 84 , lock bar mounts 86 , and rotation bar mounts 88 . FIG. 6 a shows rear seat portion 60 with back portion 14 removed and connection support box 72 raised. FIG. 6 b shows rear seat portion 60 with back portion 14 removed and connection support box 72 lowered.
[0051] FIG. 7 shows base portion 12 with the connection support box 72 removed to show additional detail. It should be appreciated that connection support box 72 is not readily removable. Lock bar mounts 86 , rotation bar mounts 88 , and support grid 84 are formed up portions that extend upward from floor 90 of tray 70 . Lock bar mounts 86 and rotation bar mounts 88 include co-linear apertures therein through which lock bar 76 and rotation bar 82 are received, respectively. Rotatable connectors 78 include apertures therein that receive rotation bar therethrough to allow free rotation of rotatable connectors 78 about rotation bar 82 . Rotatable connectors 78 include mount portions 100 . Rotatable connectors 78 are coupled to connection support box 72 at the lateral sides of tray 70 such that mount portions 100 extend through rectangular apertures in end wall 98 of connection support box 72 . Rotatable connectors 78 are thereby coupled to connection support box 72 . Accordingly, connection support box 72 is also freely rotatable about rotation bar 82 .
[0052] Connection support box 72 includes upper wall 92 , lower wall 94 , side walls 96 , and end wall 98 . Upper wall 92 is sized to have the substantially same dimensions as tray 70 . However, upper wall 92 includes apertures 102 that accommodate the curving of support beams 22 and locks 74 , and does not cover rotation bar mounts 88 . Upper wall 92 further includes upper side 104 that, when in a lowered position, provides support to a child seated in seat 10 . Upper wall 92 includes lower side 106 that includes ridges 114 . When lowered, ridges 114 engage support grid 84 to provide support to upper wall 92 and connection support box 72 generally.
[0053] In use, seat 10 is readily convertible between the full seat 10 shown in FIG. 1 , the booster seat (base portion 12 only) shown in FIG. 2 , and the storage/shipment orientation shown in FIG. 3 . To transition from the full seat 10 of FIG. 1 , a user first removes the necessary upholstery, if any, to allow access to locks 74 and allow rotation of connection support box 72 . A user squeezes on tabs 108 of locks 74 to allow unlocking and disengagement of locks 74 from lock bar 76 . Once unlocked, back portion 14 is rotated forward about rotation bar 82 . As part of this rotation, support beams 22 , rotatable connectors 78 , and connection support box 72 all rotate forward about rotation bar 82 . Once rotated forward, seat 10 is in the position shown in FIG. 3 . In this position, the distance from the bottom of base portion 12 to the height of the back of back portion 14 is smaller than the smallest dimension (height, width, depth) of the seat 10 in the upright position of FIG. 1 . Additionally, this position, FIG. 3 , provides that the back portion 14 overlaps with the base portion 12 in all three dimensions, thereby allowing for additional compactness. Indeed, both the configurations of FIG. 1 and FIG. 3 provide that the back portion 14 overlaps with the base portion 12 in all three dimensions.
[0054] From the position shown in FIG. 3 , back portion 14 can be pulled upwardly to disengage support beams 22 from connection support box 72 and rotatable connectors 78 . Once back portion 14 is disengaged, connection support box 72 and rotatable connectors 78 can be rotated back down such that the upper surface 104 of upper wall 92 again provides a seating surface. Any desired upholstery is then repositioned or re-attached to arrive at the orientation of seat 10 shown in FIG. 2 .
[0055] To transition from the seat 10 orientation shown in FIG. 2 , appropriate upholstery is pulled back or removed to expose connection support box 72 as shown in FIG. 6 b . Connection support box 72 along with rotatable connectors 78 are rotated upward to the position shown in FIG. 6 a . Back portion 14 is then lowered onto base portion 12 such that open base ends 38 of support beams 22 engage and receive rotatable connectors 78 therein. Once rotatable connectors 78 are properly seated within base ends 38 , back portion 14 , connection support box 72 , and rotatable connectors 78 are all rotated rearwardly until locks 74 engage and lock with lock bar 76 . The engagement of locks 74 with lock bar 76 prevents rotation of support beams 22 about rotation bar 82 . Additionally, engagement of locks 74 with lock bar 76 prevents movement of base beam portion 26 along longitudinal axis 34 of base beam portion 26 . Disengagement of rotatable connectors 78 from base beam portion 26 is thereby prevented.
[0056] In the configurations shown in FIG. 1 and FIG. 2 , support grid 84 provides support to lower side 106 of upper wall 92 . Thus, support grid 84 allows for clearance and coupling of base portion 12 and support beams 22 while providing a substantially similar support platform to support the child user of seat 10 .
[0057] Additionally, lower sides of lumbar housing 20 provide an arced surface 110 . Arced surface 110 is sized an shaped such that, when in the orientation of FIG. 1 , arced surface 110 has clearance relative to armrests 54 . Similarly, arced surface 110 is sized and shaped such that, when in the orientation of FIG. 3 , arced surface 110 has clearance relative to the armrests 54 , more specifically, front portions 112 of armrests 54 .
[0058] As previously noted, seat 10 can operate as a booster seat (base portion 12 only) shown in FIG. 2 . Such operation also includes the use of belt tether 140 ( FIG. 9 a - c ). Belt tether 140 includes elastic (not shown), strap 144 , and pair of retainers 146 . The elastic couples to the rear of base portion 12 . Strap 144 extends between the elastic and retainers 146 . Retainers 146 are two identical molded parts. Retainers 146 have open hook portion 148 and slotted adjuster portion 150 . One retainer 146 is rotated 180 degrees relative to the other, so open hook portions 148 are facing opposite directions. Retainers 146 are then placed next to the other so that slotted portions 150 line up. Slotted portions 150 include upper slots 152 and lower slots 154 . An end of strap 144 is threaded through the upper slots 152 on both retainers 146 , then back through lower slots 154 ( FIG. 9 a ). The end of strap 144 is then folded and sewn onto itself to prevent the retainers 146 from detaching.
[0059] The geometry of slots 152 , 154 serves to act as a sliding bar locking adjuster when load is applied to retainers 146 in a direction outward from the strap. In use, retainers 146 are spread apart and the vehicle shoulder belt is inserted so as to travel though the loop shaped opening formed by both retainers 146 together ( FIG. 9 b ). The upper end of strap 144 is pulled down to adjust and hold the vehicle shoulder-belt in the correct position on the child seated in the base portion 12 ( FIGS. 9 c , 2 ).
[0060] Base portion 12 of car seat 10 further includes rigid attachment assembly 240 . Rigid attachment assembly 240 includes two rigid rods 242 disposed within rod pathways 248 built into base portion 12 and disposed 280 mm apart and conforming to ISO 13216-1. Rigid attachment assembly 240 is used to connect seat 10 to lower anchorages provided proximate the seat bight. In addition to rods 242 , assembly 240 includes springs 244 , outward locks 246 , and inward locks 247 .
[0061] Rod pathways 248 are rectangular and define pathways in which rods 242 can slide. Rods 242 include body 250 , latch end 252 , latch release 254 , spring interface 256 , and slide bolt 258 . Latch end 252 is disposed at one end of body 250 . Latch end 252 provides a latch that engages a LATCH anchorage system. Latch end 252 is pushed on to the LATCH anchorage system to achieve fixation thereto. Rods 242 are unlatched from the LATCH anchorage system by depressing latch release 254 . Spring interface 256 is located at the opposite end of body 250 from latch end 252 . Spring interface 256 includes a portion that is secured to body 250 and a portion that is sized and shaped to fit within a cylindrical void of coil springs 244 . Slide bolt 258 passes through a bolt void in body 250 . Slide bolt 258 , in assembly, further passes through slide void 260 of rod pathways 248 . Each slide bolt 258 includes bolt head 262 having a diameter greater than a width of slide voids 260 . Slide voids 260 , with slide bolts 258 define the allowed travel of rods 242 within rod pathways 248 .
[0062] In operation, rods 242 have a stowed position where springs 244 are compressed and rods 242 are retracted within rod pathways 248 such that latch ends 252 are proximate rod pathways 248 . Rods 242 further have an extended position where springs 244 are decompressed and latch ends 252 are extended away from rod pathways 248 . Accordingly, springs 244 urge rods 242 to the extended position.
[0063] Outward locks 246 , when engaged ( FIG. 18 a ), prevent movement of rods 242 outwardly under the urging of springs 244 or otherwise. Outward locks 246 , when disengaged ( FIG. 18 b ), allow movement of rods 242 outwardly under the urging of springs 244 or otherwise. Each outward lock 246 is constructed from metal plate(s) 264 and lock spring 266 . In the illustrated embodiment, metal plate 264 is actually two abutting identically sized plates. Metal plate 264 is sized to have a width that is less than a width of rod pathways 248 . Metal plate 264 further includes rod void 268 therein. Rod void 268 is substantially rectangular in cross section and having dimensions that are slightly larger than the outer dimensions of body 250 . Metal plate 264 is further sized to extend through lock aperture 270 defined in rod pathways 248 . Metal plate 264 acts as a lever that uses the point at which it extends through lock aperture 270 as a fulcrum. Metal plate 264 is thus able to rotate to assume multiple angles relative to rods 242 (and relative to longitudinal axis 243 of rods 242 ). Lock buttons 271 rotatably engage base 12 . Rotation of lock buttons 271 provides for engagement with lock plate 264 to move lock plates 264 between the engaged and disengaged positions.
[0064] When metal plate 264 is perpendicular, or nearly perpendicular, to longitudinal axis 243 of rod 242 , rod 242 is able to move freely within rod void 268 . Absent other forces, when metal plate 264 is perpendicular to longitudinal axis 243 spring 244 are able to urge rods 242 outwardly. Placing metal plate 264 into perpendicular positioning requires compression of lock spring 266 . A user's finger, via lock button 271 , urges the portion of metal plate 264 extending outside of rod pathways 248 rearward (direction 272 ) to place metal plate 264 perpendicular to longitudinal axis 243 . Absent urging by a user's finger, lock spring 266 is able to urge metal plate 264 to a position away from perpendicular relative to longitudinal axis 243 . Furthermore, lock button 271 includes spring arm 273 that urges lock button 271 to a position that does not engage metal plate 264 . Accordingly, absent user urging, lock button 271 and metal plates 264 default to the position shown in FIG. 18 a .
[0065] When lock spring 266 urges metal plate 264 away from perpendicular, the cross section of rod void 268 , as seen from the perspective of longitudinal axis 243 , has decreased height. Accordingly, upper and lower sides of rod void 268 engage upper and lower sides of rod 242 , respectively. Such engagement prevents relative movement therebetween. Thus, because metal plate 264 is prevented from having translational movement along longitudinal axis 243 , rod 242 is similarly locked from movement along longitudinal axis 243 . Any force that would that would cause rod 242 to extend outwardly also pulls metal plate 264 to further rotate away from perpendicular. Thus, such force causes rod void 268 to exert more locking force on rod 242 . Thus, absent a user urging metal plate 264 to the perpendicular position, any force that urges rod 242 outwardly (direction 272 ) is met with rod 242 being locked in place. However, any force that would that would cause rod 242 to extend inwardly (direction 274 ) also pushes metal plate 264 to compress lock spring 266 until metal plate 264 is close enough to perpendicular to allow relative movement between metal plate 264 and rod 242 . Thus, rod 242 is able to move inward (direction 274 ) but not outward (direction 272 ). Accordingly, in use, seat 10 can become more tightly bound to a vehicle, but cannot become less tightly bound unless a user acts on metal plate 264 .
[0066] In use, rods 242 are extended by a user acting on metal plate 264 and allowing springs 244 to urge rods 242 outwardly (direction 272 ). Base portion 12 is located such that latch ends 252 are aligned with lower anchorages. Base portion 12 is then pressed rearward (direction 272 ) to cause latches in latch ends to couple to the lower anchorages. However, it should be appreciated that a force pressing base portion rearward (direction 272 ) onto lower anchorages also causes the equal and opposite force (direction 274 ) exerted by the lower anchorages onto rods 242 .
[0067] As previously discussed, forces in direction 274 exerted on rods 242 can cause movement of metal plate 264 and allow rods 242 to move in direction 274 . This can result in the inability to exert enough force on latch ends 252 to achieve latching onto lower anchorages. Thus, users could be required to directly grasp rods 242 to urge them in direction 274 . Directly grasping rods 242 can be difficult and cumbersome.
[0068] Accordingly, inward locks 247 are provided. As previously noted, bolt head 262 extends on the outer side of rod pathways 248 and travels in unison with rods 242 due to a connection therebetween. Inward locks 247 are formed from a flexible plastic and include release button 276 , fulcrums 278 , block 280 , and spring member 290 .
[0069] Inward locks 247 are coupled to the exterior of rod pathways 248 and are located substantially within exterior molding 13 of base portion 12 . Release button 276 includes first surface 292 and second surface 294 perpendicular to first surface 292 . When inward lock 247 is coupled to rod pathway 248 , first surface 292 is substantially parallel to surface 306 in which slide void 260 is formed. Block 280 is angled such that block end 296 engages surface 306 . Release button 276 , block 280 , and fulcrums 278 are formed to rigidly move together. Spring member 290 , however, while formed together with the rest of inward lock 247 , is formed to hinge in a spring-like manner relative to the balance of inward lock 247 . In assembly, outer surface 298 of spring member 290 engages an inner surface of exterior molding 13 of base portion 12 .
[0070] Accordingly, in a rest position, spring member 290 engages an inner surface of exterior molding 13 . The size and relative offset of spring member 290 to block 280 causes block end 296 to abut surface 306 . The rigid nature of inward locks 247 also proscribes that spring member 290 causes second surface 294 of release button 276 extend out of inward lock aperture 300 defined in exterior molding 13 (See FIG. 12 a ).
[0071] A user presses on the portion of second surface 294 extending out of inward lock aperture 300 to cause inward lock 247 to rotate about fulcrums 278 . Such rotation causes block end 296 to rotate away from abutment with surface 306 . Once a user stops pressing on the portion of second surface 294 extending out of inward lock aperture 300 , spring member 290 urges block end 296 to rotate towards abutment with surface 306 .
[0072] As previously discussed, as rods 242 slide within rod pathways 248 , slide bolt 258 slides within slide void 260 . Also, bolt head 262 slides along surface 306 . So as to not impede such sliding, fulcrums 278 are positioned on opposing sides of slide void 260 , giving clearance for bolt head 262 to slide between fulcrums 278 , see FIG. 15 . As movement of rods 242 nears its terminal position in direction 274 , bolt head 262 abuts surface 302 of block end 296 . Surface 302 of block end 296 is abutted by bolt head 262 when bolt head 262 moves in direction 274 . Surface 302 provides a beveled surface. Accordingly, further movement after such abutment urges inward lock 247 to rotate about fulcrums 278 causing block end 296 to rotate away from abutment with surface 306 . Bolt head 262 is thus able to travel “under” and past block end 296 . Alternatively, the user can depress second surface 294 to allow bolt head 262 and rod 242 to slide to their terminal positions in direction 274 .
[0073] Once bolt head 262 and rod 242 are at their terminal positions in direction 274 , block end 296 is able to abut surface 306 . Any movement or attempted movement of bolt head 262 in direction 272 causes bolt head 262 to abut surface 304 of block end 296 . Unlike surface 302 of block end 296 encountered by bolt head 262 when moving in direction 272 , surface 304 of block end 296 that is encountered when moving in direction 274 is not beveled. Surface 304 prevents movement of bolt head 262 . Bolt head 262 can only move past block end 296 once second surface 294 is depressed to cause block end 296 to rotate out of abutment with surface 306 of rod pathways 248 .
[0074] Accordingly, in use, a user attempting to secure seat 10 in a car activates outward locks 246 such that springs 244 can urge rods 242 to their terminal positions in direction 274 . If necessary, the user also activates inward locks to aid in bolt head 262 passing “under” block end 296 to reach its terminal position in direction 274 . Once rods 242 are fully extended, the user releases any of outward and inward locks 246 , 247 that were previously being acted upon by the user. Base portion 12 is located such that latch ends 252 are aligned with lower anchorages. Base portion 12 is then pressed rearward (direction 272 ) to cause latches in latch ends to couple to the lower anchorages. The equal and opposite force (direction 274 ) exerted by the lower anchorages onto rods 242 are countered by bolt head 262 abutting surface 304 of block end 296 . Thus, substantially all force imparted to base portion 12 is translated to rods 242 and latch ends 252 . The imparted force thus causes latch ends 252 to couple to lower anchorages. Next the user presses second surfaces 294 to unlock rods 242 from their terminal position. While keeping second surfaces 294 depressed, the user imparts force in direction 272 . This force causes rotation of metal plates 264 and compression of lock springs 266 such that rods 242 are able to move in direction 274 relative to base portion 12 which tightens the connection between base portion 12 and the seat in which base portion 12 is mounted.
[0075] Removal of base portion 12 from the seat in which is mounted is achieved as follows. First, metal plates 264 of outward locks are pressed in direction 272 to unlock outward locks 246 . Base portion 12 is then pulled in direction 274 to cause rods 242 to extend out of base portion 12 . Once latch releases 254 are out of base portion 12 and are accessible by the user, the user releases metal plates 264 . The user then depresses latch releases 254 which cause latch ends 252 to disengage from lower anchorages.
[0076] While this invention has been described as having preferred designs, 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 disclosure pertains and which fall within the limits of the appended claims. | A child car seat is provided that has a single point of actuation that simultaneously allows for adjustment of the position of the back support relative to the seat and of the headrest relative to the back support. | 1 |
FIELD OF THE INVENTION
The present invention relates to the field of nano-products, such as nanorods, nano-wires and atomic wires. More specifically, the present invention relates to the formation of such nanostructures.
TECHNICAL BACKGROUND
Nanoscale titanium dioxide, TiO 2 , or titania, has outstanding properties which can be used in wide-ranging areas. For example, TiO 2 can be used in heterogeneous catalysis, photocatalysis, solar cells, gas sensor, corrosion-protective coating, electrical devices such as varistors and so on. Thus, many TiO 2 nanostructures, including hollow spheres, nanotubes, nanowires, and mesoporous structures have been synthesised.
Typically, TiO 2 nanostructures are synthesised by chemical vapour deposition, microwave plasma torch, ultrasonic and electrochemical techniques. Other methods also used include electrospinning, sol-gel, and hydrolysis/alcoholysis of titanium precursors.
However, the most general and versatile solution-phase synthesis strategy is based on the hydrolysis and condensation of titanium alkoxides to create nanosized TiO 2 , with diameters from a few tens to several hundreds of nanometer. Owing to the very fast hydrolytic process at low temperature, this solution-phase synthesis strategy yields amorphous TiO 2 products with polydisperse size and mixed phase, and subsequent hydrothermal processing or calcinations is necessary to induce crystallisation.
Thus, these methods are tedious and the nanostructures produced have average diameters larger than 10 nm, with the smallest at 3 nm.
It is desirable to provide a method for synthesising size-tunable, relatively thin wires down to the atomic scale. Such a method could possibly broaden the application scope and enhance utility of such nano-material.
STATEMENT OF INVENTION
In a first aspect, the invention provides a method of synthesising or producing a nano-product comprising the steps of a) providing a mixture of an M-alkoxide and an unsaturated carboxylic acid, b) heating the mixture for a pre-determined period of time to form an M-complex precursor, c) precipitating a nano-product of M oxide from the M-complex precursor, wherein M is an element, the oxide of which is suitable to form a nano-product.
Preferably, precipitating a nano-product of M-oxide from the M-complex precursor in step c) comprises heating the M-complex precursor at a pre-determined temperature for a pre-determined period of time.
Typically, the M-complex precursor is an ester complex, and the M-alkoxide is titanium alkoxide, zirconium alkoxide, tin alkoxide or cerium alkoxide.
Advantageously, this invention provides the possibility of controlling the size and structure of the nano-products by controlling the temperature and time during the formation of the nano-products, wherein the higher the temperature, the greater the diameter of the nano-products and the longer the period, the longer the lengths of the nano-products. This provides the possibility of slowly growing small and fine crystalline nano- or atomic wires, having diameters as small as 0.3 nanometers.
Furthermore, the esterification of the M-alkoxide in the presence of unsaturated carboxylic acid in ambient air provides the possibility of limiting the presence of water, thus preventing significant hydrolytic process forming amorphous TiO 2 products. Preferably, the heating of the mixture for a pre-determined period of time in step b) comprises solvothermally treating the mixture.
Preferably, unsaturated carboxylic acids such as oleic acid are also used as a capping agent, capping onto the surface of the nano-products. Thus, the carboxylic acids act as a surfactant between the nano-product and the medium in which they are dispersed. This possibly improves the disperse-ability of the nano-product.
Preferably, the mixture includes an organic solvent having a boiling point ≧180° C. at ambient pressure, such as 1-octadecene. This allows the mixture to be sustained at a high temperature such as 150° C. without boiling.
Preferably, the nano-product is formed in the presence of nitrogen containing organic compound such as oleylamine, or a phosphorous-containing organic compound. This provides the possibility of forming crystallized nanostructures which are surface doped by the elements of nitrogen and phosphorus provided by nitrogen- and phosphorus-containing organic compounds. Small nano-products such as atomic wires are usually damaged by intense high-energy electron irradiation, rendering them difficult to observe by electron microscopy. Advantageously, the surface doping provides the possibility of stabilizing small atomic wires so that they can even survive high-energy electron beam irradiation, making possible their study by electron microscopy.
Preferably, the heating of the mixture is done solvothermally and in an autoclave, and between steps b) and c), the method further comprising the steps of bi) precipitating a resulting M-complex precursor, bii) re-dispersing the M-complex precursor precipitate in a second mixture, the second mixture comprising an unsaturated carboxylic acid, a nitrogen containing compound, and an organic compound which has a boiling point ≧180° C.; and biii) heating the second mixture to at least 180° C. for 1 hour.
Advantageously, the M-alkoxide is esterified in the presence of an unsaturated carboxylic acid when the cyclohexane is heated above its ambient boiling point, to provide high pressure under a solvothermal condition in an autoclave. Optionally, 1-octadecene may be used instead, which is a stable high boiling point solvent, to provide esterification at ambient pressure.
In a second aspect, the invention provides a method of synthesising or producing an atomic wire comprising the steps of precipitating M oxide to form atomic wires in the presence of a dopant-containing organic compound, wherein the dopant-containing organic compound forms a surface doping of the produced atomic wire.
Optionally, the dopant is nitrogen or phosphorus.
Advantageously, the produced nitrogen-doped atomic wires have good adsorption capacity of organic pollutant in water, and can decompose the adsorbed pollutant under visible light illumination, as demonstrated by photodegradation of methylene blue (MB).
BRIEF DESCRIPTION OF THE DRAWINGS
The file of this patent contains at least one drawing executed in color. Copies of this patent with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.
Non-limiting embodiments of the invention, by way of example only, will now be described with reference to the following drawings, in which like reference numerals refer to like parts, wherein
FIG. 1 is flowchart of a first embodiment of the invention;
FIG. 1 a is complementary flowchart to that of FIG. 1 ;
FIG. 1 c shows a possible product of the embodiment of FIG. 1 ;
FIG. 2 is a TEM image of exemplary nitrogen-doped TiO 2 atomic wires produced by the first embodiment of FIG. 1 ;
FIG. 3 is a HRTEM image of exemplary nitrogen-doped TiO 2 atomic wires produced by the first embodiment of FIG. 1 ;
FIG. 4 is a XPS survey spectrum of nitrogen-doped TiO 2 atomic wires produced by the first embodiment of FIG. 1 ;
FIG. 5 is a N is spectrum of nitrogen-doped TiO 2 atomic wires produced by the first embodiment of FIG. 1 ;
FIG. 6 is a typical TEM image of assembled TiO 2 nanorods pattern produced by a variation of the embodiment of FIG. 1 ;
FIG. 7 is a typical TEM image of TiO 2 nanorods produced by a variation of the embodiment of FIG. 1 ; and
FIG. 8 is typical TEM images showing the evolution of products, produced by the first embodiment of FIG. 1 , from Ti-complex precursor to anatase titania atomic wires and nanorods and their self-assembled networks;
FIG. 9 is a schematic representation illustrating the morphological evolution of the products, produced by the first embodiment of FIG. 1 , as a function of reaction temperature and time;
FIG. 10 is flowchart of a first embodiment of the invention;
FIG. 10 a is complementary flowchart to that of FIG. 1 ;
FIG. 11 is a typical TEM image of TiO 2 atomic wires produced by the embodiment of FIG. 10 ;
FIG. 12 is an ultraviolet-visible absorption spectrum of atomic wires produced by the embodiment of FIG. 1 ;
FIG. 13 shows the ultraviolet-visible absorption spectra illustrating efficient adsorption of methylene blue on the atomic wires produced by the embodiment of FIG. 1 ; and
FIG. 14 further illustrates efficient photocatalytic degradation of methylene blue by the atomic wires produced by the embodiment of FIG. 1 .
DESCRIPTION OF EMBODIMENTS
FIG. 1 and FIG. 1 a are flowcharts of a first embodiment of the invention, wherein anatase atomic wires are synthesised. The skilled reader knows that anatase is one of the mineral forms of titanium dioxide, TiO 2 .
In the first embodiment, 0.5 ml of titanium butoxide, Ti(OBu) 4 where Bu refers to C 4 H 9 , is slowly added dropwise into a container holding a first mixture comprising 3 ml of oleic acid (C 17 H 33 COOH) and 10 ml of cyclohexane, at step 101 .
The resulting solution is sealed in a Teflon-lined stainless autoclave, at step 101 , and heated to 150° C. and for 25 hours in a solvothermal procedure. The autoclave provides the possibility of heating cyclohexane in the mixture to 150° C. to an elevated pressure, which otherwise has a boiling point of about 81° C. in ambient pressure. In this situation, the titanium butoxide is non-hydrolytically esterified and dimerised by ester-elimination, according to the following reactions:
As illustrated in the chemical equations, the titanium butoxide decomposition is based on an efficient esterification reaction that involves chemical modification of reactive molecular precursors with oleic acid.
Thus, a sticky, viscous light yellow but transparent liquid is produced, at step 103 , which is the titanium oleate complex and is a precursor complex useable for building titanium oxide nanostructures. The titanium precursor complex is then extracted by precipitation at room temperature, using an excess amount of ethanol.
Although the amount of oleic acid is given as 3 ml, it can be any other amount as long as the amount is sufficient to facilitate efficient esterification of the titanium butoxide. Preferably, the weight ratio of the oleic acid to the titanium butoxide is in the range between 100:3 and 1:1. Beyond this range, too much oleic acid will reduce the purity of the precursor achieved from the first mixture. If too much oleic acid is introduced to the reaction system (>100:3), many by-products will be also formed and co-precipitated with precursor which will affect the quality of the final products. From another aspect, too little amount of oleic acid (<1:1) cannot provide enough capping agent to form the chelated precursor.
Subsequently, the precipitate of the titanium precursor complex is re-dispersed in a second mixture comprising 5 ml 1-octadecene, 0.6 ml of oleic acid and 0.8 ml of oleylamine. The second mixture is then heated to and maintained at 180° C. in a container such as a three-neck-flask with stirring for 1 hour in ambient air. The three neck flask allows control of the temperature and supply of an inert gas over the second mixture. This is called the ‘assembly stage’, at step 104 , where
(C 17 H 33 COO—) 2 (OC 4 H 9 )Ti—O—Ti(OC 4 H 9 )(—OOC—C 17 H 33 ) 2
is polycondensed to form atomic TiO 2 wires, which is illustrated below.
The rate of polycondensation is slow, which encourages crystallisation of small atomic wires, and prevents the formation of an amorphous mixture of TiO 2 which would happen if the rate is too fast.
Due to the presence of the oleic acid during crystallisation, the TiO 2 atomic wires are protected by an oleic acid-coordination, i.e.
whereby the oleic acid caps onto the surface of the TiO 2 . This limits side-wise growth of the atomic wires but encourages longitudinal growth. Furthermore, oleic acid advantageously moderates the reactivity of the TiO 2 by decreasing the number of TiO—R groups exposed to hydrolysis and condensation.
Preferably, surface N-doping of the TiO 2 atomic wires is also achieved, by the presence of organic amines and ambient air. For example, the oleylamine in the second mixture is prone to oxidation to form amine-hydroxide, as shown in reaction (4).
The oxidized amine is attracted to the parts of the atomic wire surface which are not capped by the oleic acid, in the form of —C—N—O—Ti. The oxidized amine provides nitrogen doping (N-doping) of wire surface. The chemical structure of the dopant and the doped surface is illustrated in reaction (5). The dopant passivates the growing atomic wire, that is, the nitrogen dopant with a long carbon chain can provide not only doping but also a surface shield of the product.
Advantageously, the TiO 2 atomic wire crystals are easily dispersed in solvents such as chloroform or hexane, as the oleic acid with long chains on the wire surface acts as a surfactant, without any sign of further growth or irreversible aggregation. Thus, the crystalline, nitrogen-doped, oleic acid capped TiO 2 atomic wires are stable, which is a feature desirable for industrial applications.
In other words, while the oleic acid functions as a surfactant, the alkyl amine functions both as a nitrogen dopant and a co-surfactant. Accordingly, parts of the TiO 2 are bonded to oleic acid and others to the oxidised amine. FIG. 1 c illustrates a crystal of the TiO 2 atomic wire, wherein each circle represents an oxygen atom possibly provided by either an oleic acid or a Ti—O—N bond with oleylamine.
Thus, providing the appropriate amount of oleic acid in the assembly stage is preferred for capping and stabilising the atomic wires and preventing lateral overgrowth. The concentration balance between the oleic acid and oleylamine in the mixture may be optimised to obtain stable atomic wires capped with oleic acid. For example, it is preferable to have a concentration ratio of oleic acid to oleyamine of between 1:1 to 1:2. Optionally, if oleic acid is omitted in the second mixture, only small TiO 2 particles are obtained. This shows that the amount of oleic acid is related to controlling the morphology of the nano product, in this case the atomic wires.
The trace amount of water present in ambient air is sufficient to allow controlled hydrolysis to form Ti—OH. The very small amount of water vapor in the air is propitious to form Ti—OH, which is an essential fragment for the crystallized TiO 2 nanostructures, and the limited water content in the air guaranties the low concentration of the Ti—OH thus avoid the overgrowth of the size of the products.
which promotes the formation of the crystallized TiO2 wires but without lateral overgrowth. (We can add hydrolysis reaction as shown above.)
The second mixture thus turns from clear and light yellow to a darker yellow as the condensation reaction proceeds, indicating the crystallisation of nitrogen-doped TiO 2 atomic wires. Subsequently, the nitrogen-doped TiO 2 atomic wires are extracted from the second mixture in air and at room temperature, again by adding an excess of ethanol. Preferably, the precipitate is further purified by centrifugation and washed twice with ethanol to remove residual surfactants at step 105 .
Accordingly, the embodiment is a method of producing a nano-product comprising the steps of (a) providing a mixture of an M-alkoxide (e.g. titanium butoxide) and an unsaturated carboxylic acid (e.g. oleic acid), at step 101 , (b) heating the mixture for a pre-determined period of time, at step 102 , (c) precipitating the nano-product of M oxide (e.g. titanium oxide), at step 104 , wherein M is an element (titanium), the oxide of which is suitable to form a nano-product (atomic wires). Preferably, precipitating a nano-product of M-oxide from the M-complex precursor in step c) comprises heating the M-complex precursor at a pre-determined temperature for a pre-determined period of time. Advantageously, the higher the temperature, the greater the diameter of the nano-product and the longer the period, the longer the lengths of the nano-product.
The described embodiment is a non-hydrolytic approach to the synthesis of anatase titania nano- or atomic wires and shall be known herein as the ‘two-stage process’, comprising a first decomposition stage for forming the titanium complex precursors in solvothermal treatment, at step 103 , followed by the ‘assembly stage’, at step 104 , wherein the controlled decomposition of Ti-containing reagents in ambient and the subsequent assembly of TiO 2 provides the possibility of synthesising nitrogen-doped TiO 2 (N:Ti in the range between 0:1 and 1:2) nano- and atomic wires.
Furthermore, the embodiment provides the possibility of by fine-controlling the growth of nano-products, e.g. by providing the possibility of adjusting the composition of the reagents including M-alkoxide, oleic acid and oleylamine, the reaction temperature, and reaction time. Accordingly, the embodiment provides the possibility of synthesising monodispersed TiO 2 wires (whether they be N-doped or non-doped) with selective diameters. Experiment data shows that the first embodiment allows selective tuning of the wire diameters between 0.3 and 0.5 nm, which virtually reaches to the atomic limit.
In a variation of the first embodiment, the assembly stage, at step 104 , heats the second mixture up to 300° C. for 1 hour in a gas stream of ambient air, at step 104 . Experiment data shows that TiO 2 nanorods with diameters of about 3 nm and lengths of about 15 nm are producible at this higher temperature.
In another variation of the first embodiment, other kinds of alkyl carboxylic acids are used in place of oleic acid to form the titanium precursor complex, such as stearic acid. The size and structure of the selected alkyl carboxylic acid affects the composition and stability of the titanium precursor complex during heating, as well as the structure and morphology of the nano-product. Using stearic acid provides the possibility of obtaining TiO 2 nanorods having a higher aspect ratio, and a uniform diameter of about 2 nm to a uniform length of about 30 nm. Furthermore, using stearic acid provides the possibility of obtaining branched nanostructures.
Tests characterising the atomic wires possibly produced by the described embodiments will now be discussed, FIG. 2 is a TEM (transmission electron microscope) image of nitrogen-doped TiO 2 atomic wires produced by the first embodiment. Inset A of FIG. 2 shows a graph for calculating the lattice spacing using a digital micrograph software. Inset B is a HRTEM (high resolution transmission electron microscope) image of a single anatase atomic wire. Inset C shows a proposed structure of the TiO 2 atomic wires observed by the TEM.
More specifically, FIG. 2 shows abundant, well-separated atomic wires with lengths up to 20 nm and diameters of 0.3-0.5 nm. The atomic wires are well dispersed on the copper grid because of the protective surface layer of oleic acid.
Oleic acid serves as both surfactant and protective layer. In the reaction process, oleic acid bond to the surface of the products to limit the growth of some special crystal faces thus to control the one dimensional growth. From this point, oleic acid is a surfactant. On the other hand, oleic acid remains on the surface of the products via chelating bond, which protect the product from aggregation and further overgrowth, actually, some surface atoms in the crystal structure of the products are provided by oleic acid, as shown in the red circle of FIG. 1 c . Taken in this sense, oleic acid is also a protection together with oleylamine. Also, oleic acid is much more abundant than N-dopant on the wire surface. Inset B shows a well-crystallized structure with the lattice fringes of about 0.35 nm (obtained from an average of 8 fringe spacings as shown in the blue line in the inset of FIG. 2 ), corresponding to the spacing between the <101> planes of the TiO 2 atomic wires.
FIG. 3 shows an even higher-magnification HRTEM image, further revealing that the TiO 2 atomic wires grow along the <001>. The corresponding Fast Fourier Transformation (FFT) pattern is also given in the inset of FIG. 3 to confirm the expected structure of the atomic wires, that is, the crystal is formed by packed planes in the <101> direction.
FIG. 4 is an XPS spectrum showing the element concentrations in the atomic wires, indicating the presence of Ti 2p (near 460 eV) and the N 1s (about 400 eV). This supports the conclusion that the TiO 2 has surface N-doping. Furthermore, FIG. 5 shows that the relatively high intensity of N 1s peak (atomic ratio of Ti:N=4.2) proves the existence of N-dopant in the atomic wire product. Moreover, the N 1s peak for the doped TiO 2 -based atomic wire is centered at around 401.0 eV, extending from 397 to 405, which is notably higher than its typical binding energy, 397.2 eV, in TiN. As the core electron binding energy of an atom is usually higher when the oxidation state of the atom is more positive, the N 1s peak can only be ascribed to nitrogen species in a higher oxidation state, such as NC or NCO, or to an NO site within a TiO 2 . This is further indicative that the N-doping of the TiO 2 atomic wires.
FIG. 6 is a TEM image of nanorods made by the variation of the first embodiment, in which the TiO 2 nanorods are prepared in the same way as the first embodiment except that titanium complex precursor is allowed to crystallize in the assembly stage at a higher temperature of 300° C., and for 1 h in a gas stream of ambient air. FIG. 6 shows that the products of the embodiment are entirely nanorods with a uniform length of about 15 nm and uniform diameter of about 3 to 4 nm. The nanorods are well dispersed on the grid and free of bundling because of the oleic acid protective coating. The HRTEM image in the insert to FIG. 6 exposes the excellent single crystal nature of the nanorods growing along the <001> direction.
FIG. 7 shows nanorods produced by another variation of the first embodiment in which stearic acid is used instead of oleic acid. The resulting nanorods have a uniform diameter of about 2 nm and uniform length around 30 nm with a tendency of branching.
FIG. 8 is the TEM images of the nano-products collected after assembly stage treatment under different temperatures and different reaction time. The titanium precursor complex obtained from the first stage, i.e. the solvothermal treatment, is an amorphous gel network, without any crystalline material (A).
After the heat treatment at 180° C. for 1 h in the presence of ODE, in the assembly stage, well dispersed atomic wires with a mean diameter of about 4.5 Å and a mean length of about 20 nm are achieved (B).
Alternatively, if at the assembly stage, the same solvothermally prepared precursor is treated instead at a higher temperature of 180° C. for 12 hours, long and bundled atomic wires are formed with an average diameter of 0.5 nm and an average length of about 38 nm (C).
Alternatively, if at the second stage, the heat treatment is conducted instead at a higher temperature of 300° C. for 20 minutes, well dispersed nanorods with a mean diameter of about 3 nm and length of about 11 nm are obtained (D). If the assembly stage process is prolonged to 1 hour, nearly monodispersed nanorods are obtained having virtually the same mean diameter of about 3 nm but a mean length increase to about 19 nm (E). If the second heating process is yet further prolonged to 3 hours, a self-assembled pattern of bundled nanorods is observed, a typical example of which is shown in FIG. 8F .
Therefore, a longer heat treatment time tends to increase the lengths but not the diameters of the atomic wires, and favours bundling and self-assembly of the atomic wires. A higher temperature, however, favours the formation of greater diameters.
Table 1 summarizes the synthesis results obtained from a series of experiments, clearly showing the effects of the reaction conditions on the size and morphology of the atomic wires.
TABLE 1
Summary of size and shape of the products obtained
under various assembly stage conditions.
Temp.
Duration
Mean dia.
Mean length
[° C.]
[h]
Morphology
[nm]
[nm]
180
1
Separated atomic wires
0.5 ± 0.1
20.0 ± 3.8
(>90%)
180
12
Bundled atomic wires
0.5 ± 0.2
38.2 ± 5.3
(>80%)
Nanodots (<20%)
300
⅓
Nanorods
3.1 ± 0.2
11.7 ± 3.3
300
1
Nanorods
3.0 ± 0.2
18.6 ± 2.3
300
3
Nanorod network pattern
3.0 ± 0.2
—
The parameters were estimated from the TEM data.
The table is also schematically illustrated in FIG. 9 , showing that increase of reaction temperature during the assembly stage mainly increases wire diameter. Furthermore, the prolonging of the assembly stage treatment time mainly increases atomic wire length, accompanied by bundling and self-assembly promoted by the presence of oleylamine.
In a second embodiment, anatase TiO 2 atomic wires is synthesised using a one-stage method, i.e. without a separate solvothermal treatment stage to prepare the titanium precursor complex separately. The embodiment is illustrated in the flowcharts of FIG. 10 and FIG. 10 a.
0.5 ml of Ti(OBu) 4 is slowly added dropwise, at step 201 , into a mixture of 3.5 ml of oleic acid and 10 ml of 1-octadecene. The resulting solution is sealed in a three-neck-flask with stirring and heated to 150° C., and kept for 48 h in ambient conditions, at step 202 . The use of autoclave is not included in this embodiment. The long period of reaction time permits the esterification reaction forming the titanium precursor complex and also the polycondensation reaction, at an elevated temperature, leading to the formation of the atomic wires to occur, without requiring a separate precipitation stage for the titanium precursor complex. That is, under an ambient pressure of 1 atmosphere, after the formation of the precursor, a prolonged reaction time favours the following reaction:
Thus the atomic wires were also observed via such reaction condition. However, both the quality and the yield of the final products are inferior to those obtained via the two stage method of the first embodiment, as shown in the comparison figure of FIG. 11 . This is because that under normal pressure, the yield of precursor is lower, and the precipitation of precursor step, the temperature for the assembly stage is lower than that for two-step method.
The resultant nano-product is extracted at room temperature. Upon adding an excess of ethanol to the reaction mixture, TiO 2 atomic wires are precipitated, at step 203 . The precipitate is further purified by centrifugation and washed twice with ethanol to remove residual surfactants, at step 205 .
As in the first embodiment, although the amount of oleic acid is given as 3 ml, it can be any other amount as long as the amount is sufficient to facilitate efficient esterification of the titanium butoxide. Preferably, the weight ratio of the oleic acid to the titanium butoxide is in the range between 100:3 and 1:1.
As in the first embodiment, the produced TiO 2 atomic wires are protected by an oleic acid-coordination and are easily re-dispersed in solvents such as chloroform or hexane, without any sign of further growth or irreversible aggregation.
Optionally, an amount of oleylamine, about 1.5 ml, is injected into the mixture when the reaction is in its 47 th hour, at step 204 , which provides surface N-doping of the TiO 2 atomic wires.
FIG. 11 is a TEM image showing that the wires produced by the second embodiment are virtually all atomic wires.
Accordingly, there are described a one-stage embodiment and a two-stage embodiment for the controlled growth of extremely thin nitrogen-doped TiO 2 atomic wires surface-modified by long-chain carboxylic acid. The atomic wires are very uniform and highly dispersible in common organic solvents.
Advantageously, the embodiments provide the possibility of producing very thin nano- or atomic TiO 2 wires, with the possibility of tuning the diameters of the nano- or atomic wires between 0.3 to 5 nm and lengths from 30 to 5 nm, or the branching of the nano- or atomic wires, by varying the reaction temperature, reaction time and choice of reagents during the precipitation or the crystallisation of the of the nano- or atomic wires.
FIG. 12 is the absorbance spectrum 1201 of the TiO 2 atomic wires produced by the described embodiments, showing that dopants such as nitrogen enable absorption of visible wavelengths (400 nm to 700 nm). This feature advantageously allows photocatalytic degradation of organic waste products using sunlight and is further explained in FIG. 13 , which illustrates absorbance spectra illustrating the adsorption efficacy of organic compounds, methylene blue (MB) in this case, on the atomic wires for photo-degradation.
Typically, organic pollutants may be treated by allowing the pollutants to adsorb to nano-size TiO 2 , such as P25 nanoparticles (average size 25 nm). The small size of the nanoparticles means there is a large surface area with which the pollutants may interact. Advantageously, the small size of the atomic wires produced by the above embodiments provides an even greater surface area than the nanoparticles. To illustrate this, 4 mg of atomic wires is added into a 2 mL centrifuge tube filled with a methylene blue solution prepared in de-ionised water (20 mg/L). The methylene blue is used to show how pollutants behave with the atomic wires.
The solution is then subject to ultrasonication in darkness for less than 10 minutes, immediately followed by centrifugation. The supernatant is then found to have turned completely colourless and clear while the atomic wires precipitated by the centrifugation have a blue colour. This is because the methylene blue has adsorbed to the atomic wires.
In comparison with a control experiment, 8 mg of P25 nanoparticles of TiO 2 (which is far larger in size than the atomic wires) is used instead of the atomic wires. Even after over 1 hour of ultrasonication, no obvious discolouration is observed after the centrifugation step.
FIG. 13 inset (b), which is pointed at by the arrow extending from the spectrum b, is a picture showing that there is no discolouration in the supernatant in the sample containing P25 nanoparticles. In contrast, inset (c), which is pointed at by the arrow extending from the spectrum c, shows that the supernatant in the sample containing the atomic wires is colourless and clear. This shows the remarkable adsorbing ability due to the exceptionally large surface-to-volume ratio of the atomic wires.
FIG. 13 also shows the UV-visible spectra of the sample, showing that the atomic wires have adsorbed about 90% of the methylene blue in the solution, whereas the adsorption of methylene blue to the P25 nanoparticles is negligible.
Furthermore, if the samples are not subject to centrifugation after adsorption, but to photocatalytic degradation under irradiation of visible light (wavelength λ>400 nm), the rate of degradation of the methylene blue can be seen, as shown in FIG. 14 . In FIG. 14 , the photodegradation of the atomic wire sample is seen to change from blue to colourless (progressing form 1 , 2 , 3 , 4 to 5 along the upper graph line 1401 . In contrast, the P25 sample does not show significant discolouration (progressing from 1 ′ to 4 ′) along the lower graph line 1402 . By monitoring the visible adsorption peak of methylene blue as a function of irradiation time, the rate of discolouration may be estimated.
It is seen that the degree of discolouration of the atomic wire sample 1040 reaches almost 100% in <35 minutes. Evidently, the atomic wires display a much higher photocatalytic activity than that of the P25 nanoparticles.
In an industrial application such as in water treatment, the atomic wires is introduced into polluted water and to allow pollutant to adsorb onto the surface of the atomic wires, so as to clean the water. This significantly concentrates the pollutant on the atomic wires for subsequently photodegradation. Accordingly, the water treatment can be conducted in two steps, the first being the pollutant adsorption and the second being photodegradation.
While there has been described in the foregoing description embodiments of the present invention, it will be understood by those skilled in the technology concerned that many variations or modifications in details of design, construction or operation may be made without departing from the scope of the present invention as claimed.
For example, the skilled man understands that although nano- and atomic wires have been described, it is understood that the invention applies to both and also other nano-structures such as branched nanowires. The definitions of nanorods, nanowires and atomic wires are not hard and fast, although it is generally understood that the aspect ratios of nanowires is bigger than that of nanorods, for example.
Furthermore, the skilled man understands that deviations from the given embodiments are included within the scope of the invention. For example, other than titanium oxides, other conceivable compounds suitable for producing nano- or atomic wires are included with the scope of the invention, such as any M-alkoxide compounds having an —O—M—O— chain structure (e.g. —O—Ti—O— in the given embodiments), where M is a suitable element for forming an oxide nanowires or atomic wires, such as zirconium or silicon alkoxides.
Furthermore, although is has been described that the dopant is nitrogen provided by a nitrogen-containing organic compound such as organic amine, the skilled man understands that other element such as phosphorus suitable for the surface doping of the nano-products may be used. For example, the dopant may be phosphorus provided by a phosphorus-containing organic compound such as organic phosphine. Where phosphorus is used, nano- or atomic wires of phosphorus-doped TiO 2 (the ratio of P:Ti is in the range between 0:1 an 1:2) are obtained.
Furthermore, although titanium butoxide is described in the embodiment, the skilled man understands that any other suitable alkoxides of suitable chain length may be used, such as titanium tetrabutoxide or titanium tetra-isopropoxide.
Furthermore, the skilled man understands that the long-chain carboxylic acid is not limited to oleic acid and stearic acid, and other forms of long-chain carboxylic acid may be used, such as and linoleic acid and arachidic acid. For example, stearic acid is a saturated alkyl carboxylic acid by which very thin nanorods but with a tendency of branching can be obtained. This is because stearic acid is a saturated alkyl carboxylic acid so that the alkyl chain is straighter than that of oleic acid. In this case, stearic acid can form a more packed and ordered array on the side of the produced nanostructures, which on one hand may limit the diameter of the final products, and on the other hand may also induce branching of the wires. | A method for the synthesis of nano-products, such as atomic titanium oxide wires. The method allows wires of anatase titanium oxide wires to be formed in a range of tunable diameters and aspect ratios in the nanometer and subnanometer size scales. The method also allows the titanium wires to be capped by oleic acid to enhance dispersing and solubility. The method allows the titanium wires to be surface doped with nitrogen species to enhance stability and functionality such as enhanced absorption in the visible wavelength region, which is useful for photodegradation of organic wastes in water by sunlight. | 2 |
RELATED APPLICATIONS
There are no previously filed, nor currently any co-pending applications, anywhere in the world.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to filters and, more particularly, to a disposable liner adapted for removable attachment to a conventional lint trap.
2. Description of the Related Art
Lint traps in domestic and commercial clothes dryers are well known. These devices, particularly utilized in automatic clothes dryers, include lint filtering screens which are positioned in the air flow path downstream of a dryer drum in order that moisture-laden lint entrained in the air stream is filtered therefrom prior to the exhaustion of the air from the dryer apparatus.
Clothes dryer manufacturers generally recommend that lint screens be cleaned preferably after each dryer load, thus requiring lint-laden screens to be laboriously cleaned and frequently replaced. Cleaning necessitates the manual removal of lint from the lint screen which invariably requires numerous attempts due to lint fragmentation and fall-off. However, cleaning of the lint screen is often neglected, thus generating an excessive accumulation of lint on the lint screen. In any event, excessive lint accumulation can impede the normal operation of the clothes dryer. Excessive lint accumulation can further cause lint to rub on the exhaust chute during removal of the screen and fall therefrom into the dryer drum atop a freshly laundered load. Moreover, lint accumulation can cause lint particles to scatter or disperse into the surrounding environment thus inducing respiratory problems and fire hazard.
Accordingly, a need has arisen for a disposable filter media being removably attachable to a conventional lint trap which allows lint to be removed monolithically therefrom in a manner which is quick, easy, and efficient. The development of the lint trap liner fulfills this need.
A search of the prior art did not disclose any patents that read directly on the claims of the instant invention; however, the following references were considered related.
U.S. Pat. No. 4,653,200, issued in the name of Werner discloses a lint screen shield assembly attached to a removable dryer lint screen.
U.S. Pat. No. 6,481,047 B1, issued in the name of Schaefer discloses a vacuum cleaner device for cleaning lint from lint traps of clothes dryers.
U.S. Pat. No. 4,720,925, issued in the name of Czech et al. discloses a lint filter housing for a dryer.
U.S. Pat. No. 5,236,478, issued in the name of Lewis et al. discloses a lint trap unit which emphasizes drastically reduced air flow within the cabinet of the dryer unit preceding an incorporated filter tray, when employed, so as to allow for an effectual precipitation on entrained moisture, lint, and other particles to the bottom of the container.
U.S. Pat. No. 5,042,170, issued in the name of Hauch et al. discloses a lint collecting device particularly suited for use in conventional domestic clothes dryers.
U.S. Pat. No. 3,648,381, issued in the name of Fox discloses a lint trap located on the door of a clothes dryer.
U.S. Pat. No. 4,115,485, issued in the name of Genessi discloses a lint interceptor for separating lint from a stream of air emanating from a clothes dryer.
U.S. Pat. No. 7,055,262 B2, issued in the name of Goldberg et al. discloses a drying apparatus comprising a chamber for containing articles to be dried, means for supplying heated dry air at a first temperature to the chamber, which air supplying means comprises an air flow pathway having means for removing moisture from air exiting the chamber and for decreasing the temperature of the air to below dew point temperature and means for increasing the temperature of the air exiting the moisture removing means to the first temperature, and a heat pump system.
Consequently, a need has been felt for a disposable filter media adapted for removable attachment to a conventional lint trap which allows lint to be removed unitarily therefrom in a manner which is quick, easy, and efficient.
SUMMARY OF THE INVENTION
Therefore, it is an object of the present invention to provide a disposable filter media adapted for removable attachment to a conventional lint trap used in automatic clothes dryers.
It is another object of the present invention to provide a disposable filter media in the form of a flexible, lightweight liner comprised of a meshed membrane adapted for snug, contiguous placement atop the lint collecting surface of a screen web of a lint trap.
It is another object of the present invention to provide a meshed membrane constructed of a material having a mesh size adapted to facilitate optimum lint capturing efficiency without an inordinate drop in the air volume in a clothes dryer.
It is another object of the present invention to provide an integral attachment means adapted to facilitate removable attachment of lint trap liner to lint trap.
It is still another object of the present invention to provide a plurality of linearly aligned lint trap liners which are formed, manufactured, packaged, and provided in a rolled form for ease of dispensing and use.
Briefly described according to one embodiment of the present invention, a lint trap liner is disclosed. The lint trap liner is adapted for removable attachment to a conventional lint trap utilized for filtering lint in automatic clothes dryers. The lint trap liner is adapted for disposable use and forms a generally rectangular configuration having an upper surface or lint contacting surface and a lower surface. The lint trap liner is adapted to capture moist lint from a stream of air exhausted from the air outlets through the exhaust chute of a clothes dryer as lint passes therethrough.
The lint trap liner comprises an elongated, flexible, tenuous meshed membrane adapted for snug, contiguous placement atop the lint collecting surface of a screen web of a lint trap. The meshed membrane is constructed of a material having a porosity or mesh size adapted to facilitate optimum lint capturing efficiency without an inordinate drop in the air volume in the clothes dryer.
An attachment means is provided in order to facilitate removable attachment of lint trap liner to lint trap. The attachment means, according to a first embodiment, comprises a plurality of tabs protruding integrally from a continuous peripheral edge of the meshed membrane. The tabs are bent in a manner so as to fixedly engage the underside of corresponding frame peripheral edge portions, thereby removably attaching liner to the lint collecting surface of screen web in a snug-fit manner.
The attachment means, according to a second embodiment, comprises a plurality of adhesive strips bonded about horizontal and vertical edges of the lint trap liner. Each adhesive strip of the plurality of adhesive strips comprises an adhesive coating bonded to the lower surface of the lint trap liner about a first horizontal edge, a second horizontal edge, a first vertical edge, and a second vertical edge of thereof. The adhesive coating is protected by a releasable liner. The adhesive strips are adapted to releasably hold the liner securely to the front side of the frame of the lint trap.
The attachment means, according to a third embodiment, comprises at least one catch assembly, wherein catch assembly comprises a pair of opposing L-shaped legs molded integral to the lower surface of lint trap liner about the horizontal sidewalls thereof. The L-shaped legs are adapted to snap into engagement with corresponding rectangular projections formed integral to the lint trap frame by a resilient, snap-fit action, thereby removably securing lint trap liner to lint trap.
It is envisioned that a plurality of linearly aligned lint trap liners are formed, manufactured, packaged, and provided in a rolled form for ease of dispensing and use. The lint trap liner is manufactured as a length of a plurality of lint trap liners which are perforated at regular intervals, along perforations. An individual lint trap liner is easily separated from the roll along a perforation, in a manner similar to separating a paper towel from a paper towel roll.
The use of the present invention allows lint to be peelably removed unitarily from a conventional lint trap in a manner which is quick, easy, and efficient. The use of the present invention also eliminates messy cleanup of airborne lint fibers and reduces fire risk.
BRIEF DESCRIPTION OF THE DRAWINGS
The advantages and features of the present invention will become better understood with reference to the following more detailed description and claims taken in conjunction with the accompanying drawings, in which like elements are identified with like symbols, and in which:
FIG. 1 is a perspective view of a clothes dryer;
FIG. 2 is a perspective view of a clothes dryer partially cut away to illustrate the interior components thereof;
FIG. 3 is a fragmentary view showing a lint trap being removed from the clothes dryer of FIG. 2 ;
FIG. 4 is a top side view of a conventional lint trap;
FIG. 5 is a bottom side view of a conventional lint trap;
FIG. 6 is a side elevational view of a conventional lint trap;
FIG. 7 is a perspective view of the lint trap liner, according to the preferred embodiment of the present invention;
FIG. 8 is a cross-sectional view of the lint trap liner illustrating adhesive bonded to the lower surface thereof, according to the preferred embodiment of the present invention;
FIG. 9 is a top plan view of the lint trap liner illustrating the concave protrusions thereof;
FIG. 10 is a top plan view of a lint trap liner, according to a first alternative attachment means;
FIG. 11 is a bottom plan view of the lint trap liner, according to the first alternative attachment means;
FIG. 12 is a bottom side perspective view of a lint trap showing the lint trap liner removably attached thereto, according to the first alternative attachment means;
FIG. 13 is a top side perspective view of the lint trap depicted in FIG. 12 showing the lint trap liner removably attached thereto, according to the preferred embodiment of the present invention;
FIG. 14 illustrates a second alternative attachment means;
FIG. 15 illustrates a third alternative attachment means; and
FIG. 16 is a perspective view of a plurality of the lint trap liner depicted in FIG. 14 , positioned into a roll with perforations at regular intervals to provide individual lint trap liners adapted to be separated from the roll.
DESCRIPTION OF THE PREFERRED EMBODIMENT
1. Detailed Description of the Figures
Referring now to FIGS. 1 and 2 , a clothes dryer 10 is shown and described generally as having a housing 12 and a front, openable loading door 14 with a handle 15 . The door 14 provides access to the interior of a rotatable drum 23 . The rotatable drum 23 rotates about a horizontal axis and has a non-rotating rear bulkhead 25 provided with air inlets 26 and air outlets 27 . The air inlets 26 are adapted for loading the interior of rotatable drum 23 with heated air via a heater 21 and the air outlets 27 are adapted for exhausting moisture, lint laden air. The rotatable drum 23 rotates via an electric motor 28 being operatively connected therewith. The electric motor 28 may also drive a fan 29 in order to facilitate airflow through the interior of rotatable drum 23 .
The clothes dryer 10 further includes a front wall 19 and a top wall 16 having a control panel 18 at a rear thereof. The control panel 18 includes a plurality of controls 20 , a number of which being manually activated to cause the clothes dryer 10 to advance through an automatic series of drying steps. The top wall 16 has a hatch 22 providing access to a lint trap 30 , shown in FIGS. 1 and 2 . The lint trap 30 is located downstream of the air outlets 27 and is removably held within an exhaust chute 24 . The lint trap 30 is inserted and removed from exhaust chute 24 through an opening 16 a defined in the top wall 16 of clothes dryer 10 . The opening 16 a provides direct passage into the exhaust chute 24 .
Referring now to FIGS. 3-6 , the lint trap 30 is shown and described generally as having an elongated frame 32 on which is mounted a screen web 90 for collecting lint 40 . The frame 32 includes a front side 32 a , to which is mounted screen web 90 , opposing a rear side 32 b. The screen web 90 forms a lint collecting surface 94 on a first side 92 thereof. Screen web 90 includes a second side 93 opposing the first side 92 . The screen web 90 may define a concave curvature 96 that forms a recessed cavity 98 . The frame 32 further includes an anterior end 33 and a posterior end 34 , wherein anterior end 33 defines a neck portion 37 having a handle 36 integrally molded or suitably affixed, such as by a spacer 38 , thereto. The frame 32 may include a row of spaced, rectangular projections 42 integrally molded to the rear side 32 b thereof. The projections 42 add structural rigidity to the frame 32 and spacings between projections 42 allow frame 32 to bend.
Referring now more specifically to FIGS. 7 and 8 , a lint trap liner 60 is provided, wherein lint trap liner 60 is adapted for releasable attachment to a lint trap 30 . The lint trap liner 60 is adapted for disposable use and forms a generally rectangular configuration having an upper surface or lint contacting surface 69 and a lower surface 67 . While lint trap liner 60 is described as having a generally rectangular configuration, other geometric configurations are envisioned in order that lint trap liner 60 may shapely and measurably correspond to lint traps 30 defining various other configurations such as circular, square, oval, and the like. The lint trap liner 60 is adapted to capture moist lint 40 from a stream of air exhausted from the air outlets 27 through the exhaust chute 24 of a clothes dryer 10 as lint 40 passes therethrough. The lint trap liner 60 comprises an elongated, flexible, tenuous meshed membrane 62 adapted for snug, contiguous placement atop the first side 92 or lint collecting surface 94 of screen web 90 . The meshed membrane 62 is sizably and flexibly adapted so as to accommodate and readily conform to the contour of the first side 92 of screen web 90 . The meshed membrane 62 is sized so as to extend across an entirety of the first side 92 of screen web 90 . The meshed membrane 62 is constructed of a material having a porosity or mesh size adapted to facilitate optimum lint capturing efficiency without an inordinate drop in the air volume in the clothes dryer 10 . The membrane 62 construction material is adapted to prevent lint 40 fibers from dissociating, scattering or dispersing from atop the lint contacting surface 69 once accumulated thereon. It is envisioned that meshed membrane 62 is fabricated of a high temperature-resistant, flexible media selected from the group which includes but is not limited to monofilament open mesh fabric, fiberglass mesh media, polyethylene and polypropylene blend mesh media, aluminum mesh, and electrostatic mesh media. Monofilament open mesh fabrics comprise polypropylene monofilament fabric and polyester monofilament fabric. The meshed membrane 62 has a porosity or mesh size ranging from about 1 to 1000 microns.
An attachment means 70 is provided in order to facilitate releasable attachment of lint trap liner 60 to lint trap 30 . The attachment means 70 , according to the preferred embodiment, comprises a thin film of adhesive 130 bonded to the lower surface 67 of the lint trap liner 60 , wherein adhesive 130 is bonded or suitably applied to lower surface 67 in such a manner so as to leave meshed openings 62 a of liner 60 uncovered. The adhesive 130 is a pressure-sensitive adhesive further defined as a releasable bond adhesive. More specifically, the adhesive 130 is comprised a formulation having a degree of tackiness sufficient to hold the liner 60 securely to the front side 32 a of frame 32 in addition to secure snug-fit engagement by liner 60 with the first side 92 of screen web 90 , but which also allows liner 60 to be peelably released unitarily or monolithically from lint trap 30 without tearing, ripping, splitting, or the like. The adhesive formulation also provides sufficient tackiness to ensure against undesirable liner 60 release from lint trap 30 as lint trap 30 is inserted, temporarily positioned inside, and removed from exhaust chute 24 .
It is envisioned that liner 60 may include a plurality of integral concave protrusions 140 extending outwardly from a continuous peripheral edge of meshed membrane 62 , as shown in FIG. 9 . More specifically, a first pair of protrusions 142 , being spatially positioned, extend outward laterally from a horizontally-oriented peripheral edge 65 of liner 60 , while a second pair of protrusions 144 , being spatially positioned, extend outward laterally from an opposing horizontally-oriented peripheral edge 66 of liner 60 . The protrusions 142 , 144 are formed in a symmetric, curvilinear manner. Such liner 60 embodiment includes, as described above, a thin film of adhesive 130 bonded to the lower surface 67 of the lint trap liner 60 , wherein adhesive 130 is bonded or applied to lower surface 67 in such a manner so as to leave meshed openings 62 a of liner 60 uncovered. The lower surface 67 of liner 60 is aligned with and releasably bonded to the first side 92 of screen web 90 . The first and second pair of protrusions 142 and 144 are folded against corresponding, opposing longitudinal sides 35 , 39 of frame 32 along the underside 32 b thereof. The protrusions 142 and 144 are adapted to conform readily to and be releasably held against opposing longitudinal sides 35 , 39 of frame along the underside 32 b thereof, thereby releasably bonding liner 60 in a snug-fit, conformational manner to lint trap 30 .
Referring now to FIGS. 10-13 , an attachment means 70 , in another embodiment, comprises a plurality of tabs 80 protruding integrally from a continuous peripheral edge of meshed membrane 62 . More specifically, a first set of tabs 81 protrude perpendicularly from a vertically-oriented lower peripheral edge 64 of liner 60 , while a second set of tabs 82 protrude perpendicularly from opposing horizontally-oriented peripheral edges 65 , 66 of liner 60 . A proximal peripheral edge 63 of liner 60 includes opposing tabs 83 a , 83 b protruding perpendicularly therefrom. Tabs 83 a , 83 b protruding along the proximal peripheral edge 63 of liner 60 define a greater length than a length defining remaining tabs 81 and 82 .
The plurality of tabs 80 are constructed of a resilient, flexible material adapted to bend to a shaped curvature and maintain the shaped curvature in its existing state until manually straightened, bent, or reshaped to an alternative configuration. In use, once liner 60 is properly aligned and placed atop the screen web 90 , the tabs 80 are bent in a manner so as to fixedly engage the underside 32 b of corresponding frame 32 peripheral edge portions, thereby removably attaching liner 60 to the first side 92 of screen web 90 in a snug-fit manner. More specifically, tabs 81 are adapted to bend and fixedly engage the posterior end 34 of frame 32 along the underside 32 b peripheral edge thereof. Tabs 82 are adapted to bend and fixedly engage corresponding, opposing longitudinal sides 35 , 39 of frame 32 along the underside 32 b thereof. Tabs 83 a and 83 b are adapted to bend and fixedly engage the anterior end 33 of frame 32 along the underside 32 b peripheral edge thereof.
Referring to FIG. 11 , the attachment means 70 , in another embodiment, comprises a plurality of adhesive strips 50 bonded about horizontal and vertical edges of the lint trap liner 60 . More specifically, each adhesive strip 50 of the plurality of adhesive strips 50 comprises an adhesive coating 52 bonded to the lower surface 67 of the lint trap liner 60 about a first horizontal edge 68 a , a second horizontal edge 68 b , a first vertical edge 68 c , and a second vertical edge 68 d of thereof. The adhesive coating 52 is a pressure-sensitive adhesive which is protected by a releasable liner 55 . The adhesive strips 50 are defined of a formulation having a degree of tackiness sufficient to hold the liner 60 securely to the front side 32 a of frame 32 , thereby ensuring snug-fit engagement by liner 60 with the first side 92 of screen web 90 , but which also allows liner 60 to be peelably removed unitarily or monolithically from lint trap 30 without tearing, ripping, or the like. The adhesive formulation also provides sufficient tackiness to ensure against undesirable liner 60 release from lint trap 30 as lint trap 30 is inserted, temporarily positioned inside, and removed from exhaust chute 24 .
Referring now to FIG. 15 , the attachment means 70 , in still another embodiment, comprises at least one catch assembly 100 , wherein catch assembly 100 comprises a pair of opposing L-shaped legs 102 molded integral to the lower surface 67 of lint trap liner 60 about the horizontal sidewalls 68 a and 68 b thereof. The L-shaped legs 102 each includes a vertical member 103 having a foot portion 104 extending angularly from a lower end thereof at approximately 90°. The L-shaped legs 102 are linearly aligned and each comprises a boss 105 projecting downwardly from the foot portion 104 thereof. The boss 105 forms a projection receiving cavity 110 adapted to frictionally receive a corresponding rectangular projection 42 of the lint trap frame 32 in a snap-fit manner. The L-shaped legs 102 are adapted to snap into engagement with corresponding rectangular projections 42 of the lint trap frame 32 by a resilient, snap-fit action, thereby removably securing lint trap liner 60 to lint trap 30 . More specifically, the lower surface 67 of lint trap liner 60 is engaged against the first side 92 of screen web 90 and the L-shaped legs 102 of liner 60 are snapped into engagement with corresponding rectangular projections 42 of frame 32 .
It is envisioned other attachment mechanisms and methods such as hook and loop fasteners may be utilized to facilitate removable attachment of lint trap liner 60 to lint trap 30 .
Referring now to FIGS. 7-14 , and more particularly to FIG. 16 , as will be described in greater detail below, it is envisioned in another embodiment that a plurality of linearly aligned lint trap liners 60 are formed, manufactured, packaged, and provided in a rolled form 122 for ease of dispensing and use. For purposes of disclosing the best available mode concerning this embodiment, and not by way of limitation regarding the functionality or design of the present invention, the lint trap liner 60 is manufactured as a length of a plurality of lint trap liners 60 which are perforated at regular intervals, along perforations 120 . An individual lint trap liner 60 is easily separated from the roll 122 along a perforation 120 , in a manner similar to separating a toilet tissue from a toilet tissue roll (not shown) or a paper towel from a paper towel roll (not shown). The perforations 120 may include any combination of short and long scores 124 or slits separated by short and long portions of lint trap liner 60 material. Scores 124 or slits are intended to include indentations in the lint trap liner 60 material which do not penetrate completely therethrough.
Each liner 60 comprises a flexible, tenuous meshed membrane 62 adapted for releasable attachment to a lint trap 30 . The membrane 62 has a lint contacting surface 69 opposing a lower surface 67 and is otherwise defined as being substantially identical to the lint trap liner 60 as described above according to the preferred embodiment of the present invention. It is envisioned, however, that this embodiment may also comprise membranes 62 each having a plurality of integral concave protrusions 140 extending outwardly from a continuous peripheral edge thereof, as described above in greater detail.
In order to facilitate releasable attachment of an individual lint trap liner 60 to the lint trap 30 , an attachment means 70 is provided. For purposes of describing this embodiment, the attachment means 70 comprises a thin film of adhesive 130 bonded to the lower surface 67 of membrane 62 , as described above according to the preferred embodiment, but may comprise alternative attachment means 70 as also described in detail above. The attachment means 70 is adapted to facilitate releasable attachment of each individual membrane 62 to the lint trap 30 .
Alternative storage and dispensing configurations are contemplated. The liner 60 is further envisioned to be commercially available in the form of pre-measured sheets of uniform or non-uniform dimensions adapted to be stacked upon one another in a desired successional arrangement and dispensed from a suitable dispensing apparatus, such as a box or carton.
The use of the present invention allows for lint 40 , having accumulated on the meshed media which is attached superjacent to a lint trap 30 , to be peelably removed unitarily from lint trap 30 in a quick, easy, and efficient manner. The lint-accumulation and adherence feature of the present invention also prevents lint 40 or lint particles from scattering into the surrounding environment and falling onto the clothes dryer 10 or a clothes load during removal of the lint trap 30 with attached liner 60 .
2. Operation of the Preferred Embodiment
To use the present invention, user removably attaches the lint trap liner 60 to the lint collecting surface 94 of the screen web 90 of a lint trap 30 in a superjacent manner using the attachment means 70 . User next inserts the lint trap 30 with attached lint trap liner 60 through the exhaust chute 24 of a clothes dryer 10 in a manner such that the lint contacting surface 69 of liner 60 faces downwardly. User then executes a number of automatic clothes drying loads until a quantity of lint 40 has accumulated atop the lint contacting surface 69 of liner 60 requiring the lint trap 30 with attached liner 60 to be removed for cleaning. User then peelably removes lint-laden liner 60 from lint trap 30 and properly disposes of liner 60 . The lint trap liner 60 is adapted to peel unitarily from the lint trap 30 .
The use of the present invention allows lint to be peelably removed unitarily from a conventional lint trap in a manner which is quick, easy, and efficient.
Therefore, the foregoing description is included to illustrate the operation of the preferred embodiment and is not meant to limit the scope of the invention. As one can envision, an individual skilled in the relevant art, in conjunction with the present teachings, would be capable of incorporating many minor modifications that are anticipated within this disclosure. The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents. Therefore, the scope of the invention is to be broadly limited only by the following Claims. | A disposable filter media removably attachable to a conventional lint trap utilized in automatic clothes dryers is provided. The disposable filter media is in the form of a flexible, lightweight meshed liner adapted for snug, releasable attachment atop the lint collecting surface of a lint trap. The liner functions to provide optimum lint capturing efficiency without an inordinate drop in the air volume in a clothes dryer and is easily removed and disposed of after use. | 3 |
FIELD OF THE INVENTION
The present invention relates to processes for preparing said silanes via hydrosilation reactions between hydroalkyldialkoxyilanes and olefinic reactants, wherein heretofore unrecognized rearrangement reactions, which generate undesired, close-boiling by-products, are minimized.
BACKGROUND OF THE INVENTION
Organofunctional alkoxysilanes have established and broad utilities as coupling agents, adhesion promoters, or crosslinking agents in applications involving inorganic fillers and substrates, and organic polymers. Most of such organofunctional silanes in commercial use in terms of both volumes produced and breadth of applications have been trialkoxysilanes, i.e., having three reactive alkoxy groups attached to each silicon atom, in addition to one organofunctional group.
The chemistries leading to the related alkyldialkoxysilanes have also long been known, but these products have not achieved the same high level of commercial success and are not produced in similarly large commercial volumes. There are several reasons for these differences, and these differences are reflected in less efficient processes, lower yields, and higher prices for organofunctional alkyldialkoxysilanes, making them less accessible in the marketplace.
In Journal of the American Chemical Society, Vol. 81, pp. 2632-2635(1959), Plueddemann and Fanger report the respective reactions of dimethylethoxysilane, methyldiethoxysilane, and triethoxysilane with allyl glycidyl ether as giving single products in substantially quantitative yields without presenting purity data, while isomeric products were detected in a related hydrosilation of butadiene monoepoxide. In each case, the hydrosilyl reactant was added to the olefinic epoxide. In the same journal, Volume 79, pp. 3073-3077(1957), Goodman et al report the hydrosilations of vinyl ethyl ether, vinyl n-butyl ether, and allylidene diacetate with methyldiethoxysilane by adding the olefin to the silane.
When methyldiethoxysilane is treated with chloroplatinic acid under hydrosilation conditions, a hydrogen/alkoxy exchange reaction is reported, without alkyl/alkoxy exchange (Chemical Abstracts, Volume 82, abstr. 16884v(1975), in English as Journal of General Chemistry, USSR, Volume 44, pp. 1744-5(1974)). More recently, U.S. Patent No. 4,966,981 discloses hydrosilations of allyl glycidyl ether wherein added alcohol is used to attain high product purity by reducing the level of formation of internal adducts to the allyl group vs. the formation of desired terminal adducts. All examples are run by adding the SiH-containing reactant to a stoichiometric excess of the olefinic reactant.
The art discloses a methyl/trimethylsiloxy group exchange which occurs when internal olefins (2-hexene, cyclohexene) are hydrosilated with bis(trimethylsiloxy)methylsilane, (Me 3 SiO) 2 MeSiH. Speier et al report in Journal of Organic Chemistry, Volume 30, pp. 1651-2 (1965) that such hydrosilations are accompanied by a methylltrimethylsiloxy group exchange.
While hydrosilation reactions have been run by adding the olefinic reactant to the hydrosilane on trialkoxy silanes, that mode has not been used generally because of safety hazards. See, for example, U.S. Pat. Nos. 4,160,775 and 5,559,264.
There appears to be no known example of alkyl/alkoxy group exchange reaction occurring during hydrosilation reactions of hydroalkyldialkoxysilanes with olefins. Alkyl/alkoxy group exchange reactions have been reported for simple methylalkoxysilanes at high temperatures with strong base catalysts, but these involve neither hydroalkyldialkoxysilanes nor hydrosilatable olefins. See Ryan, Journal of the American Chemical Society, Volume 84, p. 4730(1962).
SUMMARY OF THE INVENTION
The present invention provides a method for preparing high purity organofunctional alkyldialkoxysilanes wherein the formation of undesired by-products from a previously unrecognized alkyl/alkoxy group exchange reaction is minimized. The process involves the addition of the alkyldialkoxy silane to the allylic species to affect the hydrosilation.
DETAILED DESCRIPTION OF THE INVENTION
The reactions of interest herein may be represented by the following general equation, ##STR1## wherein R is a lower alkyl group of one to four carbon atoms, R 1 is hydrogen or R, x is an integer of 1 to 15, and Y is R or a carbon-, oxygen-, nitrogen-, or sulfur-bonded functional group with the provisos that when x=1, Y is not a halogen and that x may be 0 when Y is a carbon-bonded functional group wherein the bonding carbon is also attached only to carbon or hydrogen atoms or Y is a silicon-bonded functional group. The major product is R(RO) 2 SiCH 2 CHR 1 (CH 2 ) X Y, the exchange reaction products, R 2 (RO)SiCH 2 CHR 1 (CH 2 ) x Y and (RO) 3 SiCH 2 CHR 1 (CH 2 ) x Y, are minor products. The olefinic compound, CH 2 ═CR 1 (CH 2 ) x Y, also represents cyclic and linear olefins wherein the double bond is not in a terminal position, including olefins formed by isomerization of CH 2 ═CR 1 (CH 2 ) x Y, as, for example, CH 3 CR 1 ═CH(CH 2 ) x-1 Y, which normally accompanies hydrosilation.
The present invention is concerned primarily with the alkyl/alkoxy group exchange reaction, leading to the by-products R 2 (RO)SiCH 2 CR 1 (CH 2 ) x Y and (RO) 3 SiCH 2 CR 1 (CH 2 ) x Y, plus their precursors, R 2 (RO)SiH and (RO) 3 SiH, and processes for their minimizaton, such that the desired product, R(RO) 2 SiCH 2 CR 1 (CH 2 ),Y, can be obtained in high purity, by routine purification means, as by distillation. Said high purity should be greater than 95%, with the content of the alkyl/alkoxy exchange reaction products being less than 1% combined total. As an added advantage, the processes of the present invention also allow use of lower molar excesses of the olefinic reactant, due to lowered degree of isomerization of said olefinic reactant during the hydrosilations.
The process is run preferably in a mode wherein the olefinic reactant, CH 2 ═CR 1 (CH 2 ) x Y, is added to the hydroalkyldialkoxysilane reactant, R(RO) 2 SiH, in the presence of a platinum-containing catalyst. Thus, the silane reactant would be in the stoichiometric excess in the reaction vessel, at the desired temperature level with the catalyst as the olefin is added to the the reactor, until about a stoichiometric equivalent of the olefin is added.
The hydroalkyldialkoxysilane reactant, R(RO) 2 SiH, where R is a lower alkyl group of one to four carbon atoms and may be the same or different in a given molecule, includes compounds ranging from methyldimethoxysilane to butyldibutoxysilane, where butoxy- may be n-butoxy-, i-butoxy-, s-butoxy-, or t-butoxy-, but is preferably selected from the group of methyldimethoxysilane and methyldiethoxysilane. These silanes are generally made by reactions of methyldichlorosilane, MeSiHCl 2 , with at least two molar equivalents of the corresponding alcohol.
The platinum-containing catalyst are well-known hydrosilation catalysts, namely solutions of or derived from chloroplatinic acid and platinum-olefin complexes including platinum-vinylsiloxane complexes. Various additives and promoters known in the art may be used with the platinum catalyst, depending on the olefinic reactant. Such additives and promoters may include acids such as acetic acid, bases such as triethylanrine or phenothiazine, alcohols, such as methanol or ethanol, inorganics such as sodium carbonate or potassium carbonate, where such additives or promoters are used to increase rates or minimize known side reactions. Acetic acid is a preferred additive for the hydrosilation processes of the present invention at a use level of 100 to 5000 parts per million by weight of the combined reactants. Solvents, which have the effect of lowering unit yields by occupying unit volume, may be used if desired, but are not a requisite feature of the present invention.
The olefinic reactant, CH 2 ═CR 1 (CH 2 ) x Y, where R 1 is hydrogen or R as defined above, x is an integer of 1 to 15, and Y is R or a carbon-, oxygen-, nitrogen-, or sulfur-bonded functional group with the proviso, when x=1, Y cannot be a halogen and that x may be 0 when Y is a carbon-bonded functional group wherein the bonding carbon is also attached only to carbon or hydrogen atoms or Y is a silicon-bonded non-halo functional group, can be selected from a wide variety of functional olefins, including hydrocarbon olefins such as octene or vinylcyclohexene, and including functional olefins now in commercial use in hydrosilation processes. Examples of Y are thioethers, ethers, epoxides, carbamatos, isocyanatos, polyethers, amines and alkyls. Specific examples of Y are glycidoxy, 3,4-epoxycyclohexyl, methacryloxy, polyetheroxy, 4-hydroxy-3-methoxyphenyl, n-pentyl, and the like. The olefins thus include allyl esters, such as allyl methacrylate, allyl glycidyl ethers, other allylic ethers including allyl polyethers, allyl aromatics such as eugenol, the corresponding methallyl compounds, and olefins not represented by the general formula, including cycloolefins such as cyclohexene, non-terminal olefins such as tertiary-amylene and those formed by isomerization of CH 2 ═CR 1 (CH 2 ) x Y, acetylene and substituted acetylenes, vinyl cycloalkene epoxides, and vinylic silanes including vinyltrialkoxysilanes. The commercially useful olefins are preferred, with allyl glycidyl ether being most preferred.
The ratio of olefinic reactant to hydroalkyldialkoxysilane reactant will generally be close to or greater than 1. It is generally preferred to use a molar excess of the olefinic reactant to ensure consumption of the silicon-bonded hydrogen groups, while allowing for side reactions which also consume the olefinic reactant, such as isomerization and reduction. A preferred ratio of olefinic reactant to hydroalkyldialkoxysilane reactant is 1.01 to 2, with 1.05 to 1.3 being most preferred. The processes of the present invention, performed by adding the olefinic reactant to the hydroalkyldialkoxysilane reactant, allow the ratio to be in the lower part of the range, i.e., 1.05 to 1.15. It is noteworthy that the latter lower ratios appear to be unique to the hydroalkyldialkoxysilanes, and that consumption of all the SiH-containing reactant at such low ratios is not observed as generally with trialkoxysilanes, such as trimethoxysilane.
Reaction conditions are typical of those for commercially practiced hydrosilations except that the olefinic reactant is preferably added to the hydroalkyldialkoxysilane in the presence of the platinum catalyst. Reaction temperatures are elevated, in the range of 50 to 150° C., preferably 75 to 105° C., and most preferably 80-100° C. Platinum catalyst concentrations are in the range of 5-100 parts per million (ppm) of Pt by weight of the combined reactants, preferably in the range of 10-50 ppm, and most preferably in the range of 10-20 ppm. Reaction pressures are normally atmospheric, for convenience, although these reactions can be run at subatmospheric or superatmospheric pressures if the equipment is capable. Purification, as by distillation, is typically run under vacuum.
The processes of the present invention can be practiced in a variety of equipment suitable for the purpose of hydrosilation reactions ranging from small laboratory glassware through pilot scale to large production units. The only needs are for means of heating, cooling, maintenance of an inert atmosphere, preferably nitrogen, means for adequate agitation, means for introduction of reactants and catalyst in controlled fashion, and means for purifying the reaction products, as by distillation.
Whereas the exact scope of this invention is set forth in the appended claims, the following specific examples illustrate certain aspects of the present invention and, more particularly, point out various aspects of the method for evaluating same. However, the examples are set forth for illustrative purposes only and are not to be construed as limitations on the present invention. The abbreviations g, ml, mm, mol, ppm, μl, L, lb, kg, GC, and MS respectively represent gram, milliliter, millimeter, molar equivalent, parts per million, microliter, liter, pound, kilogram, gas chromatography, and mass spectrometry. All temperatures are reported in degrees Centigrade, and all reactions were run in standard laboratory glassware or pilot scale or production units at atmospheric pressure under an inert atmosphere of nitrogen, and all parts and percentages are by weight.
EXAMPLES
Comparative Example 1
Hydrosilation of Methyldiethoxysilane and Allyl Glycidyl Ether by Prior Art Addition
To a 250 ml 4-neck round bottom flask, equipped with stir bar, thermocouple probe, condenser, addition funnel and nitrogen inlet/outlet, were added 70.8 g (0.62 mol) of allyl glycidyl ether (AGE). A 20% excess of the raw material was used in the preparation, as some isomerization of AGE occurs in the presence of heat and platinum catalyst. A solution of 10% chloroplatinic acid in ethanol (CPA, 78 μl, 15 ppm Pt) catalyst and 90 μl (650 ppm) of acetic acid were added to the AGE in the reaction vessel. The mixture was heated to 85° C. Methyldiethoxysilane (67.0 g, 0.52 mol), which had been charged to the addition funnel, was added drop-wise to the heated mixture at such a rate as to keep the pot temperature between 85-90° C. After silane addition completion (about 80 minutes), the reaction was heated at 85° C. for 30 minutes. GC Analysis showed, besides AGE and isomers, 81.1% of desired product, γ-glycidoxypropylmethyldiethoxysilane.
Also present were two unexpected scrambled products:
γ-glycidoxypropyldimethyl(ethoxy)silane (1.10% by GC) and γ-glycidoxy-propyltriethoxysilane (1.24% by GC). GC-MS Data of the above mixture support the structures of the product and two scrambled side-products.
Example 1
Hydrosilation of Methyldiethoxysilane and Allyl Glycidyl Ether by Inverse Addition
To the apparatus of Comparative Example 1 were added 67.0 g (0.52 mol) of methyldiethoxysilane, 78 μl (15 ppm Pt) of 10% CPA solution and 90 μl (650 ppm) of acetic acid. The mixture was heated to 85° C. AGE (70.8g, 20% excess at 0.62 mol), which had been charged to the addition funnel, was added drop-wise to the heated mixture at such a rate as to keep the pot temperature between 85-90° C. After AGE addition completion (approximately 80 minutes), the reaction was then heated at 85° C. for 30 minutes. GC analysis of the crude reaction mixture also showed complete conversion of the methyldiethoxysilane. GC analysis showed, besides AGE/isomers, 75.3% of desired product, γ-glycidoxypropylmethyldiethoxysilane. Again present, though in much smaller amounts, were the two side products γ-glycidoxypropyldimethyl(ethoxy)silane (0.16% by GC) and γ-glycidoxypropyl-triethoxysilane (0.36% by GC).
Example 2
Hydrosilation of Methyldiethoxysilane and 11% Excess Allyl Glycidyl Ether by Inverse Addition
To the apparatus of Example 1 were added 67.0 g (0.52 mol) of methyldiethoxysilane, 78 μl (15 ppm Pt) of 10% CPA solution and 90 μl (650 ppm) of acetic acid. The mixture was heated to 85° C. Next, an 11% molar excess of AGE (64.0 g, 0.58 mol) was added drop-wise from an addition funnel to the heated mixture at such a rate as to keep the pot temperature between 85-90° C. After AGE addition completion (50 minutes), the reaction was heated at 85° C. for 30 minutes. GC analysis showed, besides AGE/isomers, 89.6% of desired product, γ-glycidoxypropylmethyldiethoxysilane. Present, although in smaller amounts, were the two scrambled products γ-glycidoxypropyldimethyl-(ethoxy)silane (0.29% by GC) and γ-glycidoxypropyltriethoxysilane (0.34% by GC).
Example 3
Hydrosilation of Methyldiethoxysilane and Allyl Glycidyl Ether at Larger Scale by Inverse Addition
To a jacketed 50 L glass vessel equipped with agitator, thermocouple probe, condenser and nitrogen atmosphere were pressure charged 48.0 lb [21.8 kg] (50 lbs [22.7 kg]×96% purity, 162.8 mol) of methyldiethoxysilane from a 10 gallon Pope can. After addition of 10% CPA solution (20.0 ml or 15 ppm Pt) and acetic acid (25.0 ml or 550 ppm ) through the handhole, the reactor was kept under nitrogen purge, sealed and heated to 85° C. Allyl glycidyl ether (49.0 lb [22.3 kg], using a 20 mole % excess of 195.4 mol) was introduced through a TEFLON line to the mixture in the 50 L reactor also from a pressurized Pope can. The AGE was added at such a rate as to keep the reaction temperature between 85 and 100° C. This resulted in a rate of about 20 lb [9.1 kg]/hr. After over 2.5 hr, the addition was complete and the kettle was cooled to 50° C. for sampling. GC analysis found the methyldiethoxysilane (0.04% remaining) to be almost completely converted to hydrosilation product. After a lites strip, the crude product was vacuum distilled at 123-133° C. (6.5-8.0 mm Hg) to yield 78.35 lb. (35.53 kg) of 98.3% pure material by GC. This is a percent conversion of 88.2%. Also present were the two scrambled products γ-glycidoxypropyldimethyl (ethoxy)silane (0.44% by GC) and γ-glycidoxypropyltriethoxysilane (0.37% by GC).
Example 4
Another Hydrosilation of Methyldiethoxysilane and Allyl Glycidyl Ether at Larger Scale by Inverse Addition
Again, to the apparatus of Example 3 were pressure charged 49.6 lb [22.5 kg] (168.2 mol) of methyldiethoxysilane from a 10 gallon Pope can. After addition of the 20.0 g of CPA ethanol solution (15 ppm Pt) and 21.0 ml (460 ppm) of acetic acid through the handhole, the reactor was kept under nitrogen purge, sealed and heated to 85° C. Allyl glycidyl ether (50.6 lb [23 kg], 20 mole % excess or 210.8 mol) was added through a line to the mixture in the reactor from a pressurized can. The AGE was added at a rate that kept the reaction temperature between 85 and 95° C. After two hours, the addition was complete and the hydrosilation lites were stripped. The crude product was vacuum distilled at 104-121° C. (3-7 mm Hg) to yield 75.5 pounds (31.23 kg) of γ-glycidoxypropylmethyldiethoxysilane with an average purity of 99.0%. This represents a conversion of 82.3%. Again present were the silane scrambled products γ-glycidoxy-propyldimethyl(ethoxy) silane (0.39% by GC) and γ-glycidoxypropyltriethoxysilane (0.27% by GC).
Comparative Example 2
Hydrosilation of Methyldiethoxysilane and Allyi Glycidyl Ether in a Pilot Scale Reactor by Prior Art Addition Conditions
To a jacketed Hastelloy-C reactor, equipped with agitator, temperature probe, condenser and nitrogen purge, were added 391 lb [177.7 kg] (1559 mol) of allyl glycidyl ether (AGE), followed by 151 ml (15 ppm Pt) of 10% CPA catalyst solution and 0.36 lb [164 g] (470 ppm) of acetic acid promoter. The reactor contents were heated to 80° C. Methyldiethoxysilane (370 lb [168.2 kg], 1255 mol) was metered in at such a rate as to keep the reactor temperature between 80-90° C. After completion of reaction, about 3.5 hours of silane addition and a one hour hold, a majority of the excess AGE/isomers were stripped to give a crude GC yield of 86.3% desired hydrosilation product. GC Analysis also showed 2.53% γ-glycidoxypropyldimethyl(ethoxy)silane and 2.95% γ-glycidoxypropyltriethoxysilane.
Example 5
Hydrosilation of Methyldiethoxysilane and Allyl Glycidyl Ether in a Pilot Scale Reactor by Inverse Addition
To the reactor of Comparative Example 2 were added 370 lb [168.2 kg] (1255 mol) of methyldiethoxysilane, followed by 151 ml of 10% CPA catalyst solution (15 ppm) and 0.36 lb [164 g] (470 ppm) of acetic acid promoter. The reactor contents were heated to 80° C. AGE (390 lb [177.3 kg], 1559 mol) was added at a rate to keep the reactor temperature between 80-90° C. After completion of AGE addition (about 3.5 hours) and heating for one hour at 85° C., a portion of the excess AGE/isomers were stripped to give a crude GC yield of 82.1% desired hydrosilation product. GC Analysis also showed 0.14% γ-glycidoxypropyldimethyl(ethoxy)silane and 0.29% γ-glycidoxypropyltriethoxysilane. Further purification of crude γ-glycidoxypropylmethyldiethoxysilane by continuous high vacuum distillation did not separate the close-boiling exchanged side-products from desired product. Results were: γ-Glycidoxypropyltriethoxysilane was 1.3%, and γ-glycidoxypropyldimethyl(ethoxy)silane was 2.1% by GC analysis. Expected product, γ-glycidoxypropylmethyldiethoxysilane, accounted for only 94.0% of the distilled material. Redistillation in batch fashion through a fractionation column was required to provide product with greater than 97% purity by GC and combined exchanged products which were less than than 1%. Approximately 25% of the desired product was contained in less pure distillation cuts and the distillation heavies.
Example 6
Hydrosilation of Methyldiethoxysilane and Allyl Glycidyl Ether in a Production Reactor by Inverse Addition
To a jacketed, glass-lined reactor, equipped with agitator, condenser and nitrogen purge, was added 6500 lb [2955 kg] (22,049 mol) of methyldiethoxysilane. CPA catalyst solution (2650 ml, 15 ppm Pt) and acetic acid promoter (6.30 lb [2.9 kg], 470 ppm) had previously been added. The reactor contents were heated to 80° C. Controlled addition of allyl glycidyl ether (6860 lb [3118 kg], 27,353 mol) to the heated mixture was then commenced. The feed controlled kettle temperature was maintained around 85° C. Again, a 20% excess of AGE is used, as competitive isomerization of AGE occurs in the presence of heat and catalyst. At the end of the AGE addition (about 7 hours), the reaction mixture was heated to 85° C. and agitated for 60 minutes. Reaction completion was determined by SiH content analysis. The lites, including excess AGE/isomers, were then stripped at reduced pressure. Crude reaction yield was 97.3% by GC analysis. Also present were the following rearranged side-products:
γ-glycidoxypropyldimethyl-(ethoxy)silane (0.10%) and γ-glycidoxypropyltriethoxysilane (0.17%). The stripped crude was then filtered and vacuum distilled (2 mm Hg) in a continuous unit, providing product of greater than 98% purity.
Comparative Example 3
Hydrosilation of Methyldiethoxysilane and Ailvy Glycidyl Ether under Continuous Conditions
When the hydrosilation reaction between methyldiethoxysilane and allyl glycidyl ether was run in a continuous mode (See copending U.S. patent application Ser. No. 09/151,642, now U.S. Pat. No. 6,015,920, for continuous hydrosilation with recycling) by cofeeding allyl glycidyl ether and excess methyldiethoxysilane to a reactor and recycling the excess methyldiethoxysilane, both exchanged precursors, Me 2 (EtO)SiH and (EtO) 3 SiH, were observed in the recycle stream at combined levels ranging from approximately 5% to greater than 20% of the recycled methyldiethoxysilane stream, and the crude product stream contained steadily increasing amounts of exchanged hydrosilation products as well as reaction time increased. The level of γ-glycidoxy-propyldimethylethoxysilane, for example, increased from approximately 0.5% to more than 2% relative to 70 to 78% of the expected γ-glycidoxypropylmethyldiethoxysilane.
Comparative Example 4
Hydrosilation of Methyldiethoxysilane and Vinylcyclohexene Monoxide by Prior Art Addition
When the hydrosilation reaction between methyldiethoxyislane and vinylcyclohexene monoxide was run by adding the former to a 20% molar excess of the latter at 90° C., followed by a 1 hr hold at 90° C. after completion of the addition, using 10 ppm of platinum as a solution in ethanol, in the presence of aproximately 300 ppm of sodium propionate, in separate runs with and without 500 ppm of acetic acid, the alkyl/alkoxy group exhange reaction hydrosilation products were observed by GC at combined levels of 2.4-3.4% relative to the expected methyldiethoxysilane hydrosilation product at 82-84%. The acetic acid did not appreciably affect the reaction products.
Comparative Example 5
Hydrosilation of Methyldiethoxysilane with Other Olefins by Prior Art Addition
A series of small hydrosilation reactions was run by adding methyldiethoxysilane to 1-octene, cyclohexene, 2,3-dimethyl-2-butene (tertiary-amylene), and eugenol. In each reaction, evidence of alkyl/alkoxy group exchange was observed by GC and confirmed by GC/MS. For 1-octene, the exchanged hydrosilation products were both observed. For cyclohexene, both exchanged precursors were observed, with only the dimethylethoxysilane hydrosilation product being observed. Results similar to those with cyclohexene were observed for tertiary-amylene and for eugenol, i.e., both precursors and the hydrosilation product of dimethylethoxysilane.
Example 7
Hydrosilation of Methyldiethoxysilane and 1-Octene by Inverse Addition
The hydrosilation of methyldiethoxysilane and 1-octene as reported in Comparative Example 8 provided combined exchanged products, Me 2 (EtO)SiC 8 H 17 , and (EtO) 3 SiC8H 17 , as high as 7.6% relative to 80.4% of expected Me(EtO) 2 SiC 8 H 17 . When run by inverse addition, the combined exchanged products were 0.9%, and when run by inverse addition in the presence of acetic acid, the combined exchanged products were 0.6%, both relative to 80% of expected product.
Example 8
Hydrosilation of Methyldimethoxysilane and 1-Octene by Inverse Addition
When the hydrosilation of methyldimethoxysilane and 1-octene was run under conditions of Comparative Example 5, the exchanged hydrosilation products, Me 2 (MeO)SiC 8 H 17 and (MeO) 3 SiC 8 H 17 , were shown by GC analysis to be a combined 0.6% relative to 65.7% Me(MeO) 2 SiC 8 H 17 (0.6% normalizes to greater than 1% at 100% Me(MeO) 2 SiC 8 H 17 ). When run by inverse addition in the presence or absence of acetic acid, the combined exchange products were minimized to less than 0.2% relative to 72.9% Me(MeO) 2 SiC 8 H 17 . | A method is provided for preparing high purity organofunctional alkyldialkoxysilanes by reacting hydroalkyldialkoxysilanes with olefins wherein formation of undesired close-boiling by-products by an alkyl/alkoxy group exchange reaction is minimized. | 2 |
TECHNICAL FIELD
[0001] The present invention relates to a serial configuration linear motor which, thanks for having a driving structure consisting of a plurality of linear movers, facilitates handling in the course of assembly; which can cancel cogging force; and which can provide thermal protection of the movers.
RELATED ART
[0002] FIG. 6 shows a related-art linear motor.
[0003] In the drawing, reference numeral 1 ′ denotes a mover of the related-art linear motor constituted of a single armature; and reference numeral 6 ′ denotes a stator constituted of a magnetic field originating from a plurality of permanent magnets. Meanwhile, the armature has a polyphase balancing winding. The linear motor is configured such that the mover 1 ′ and the stator 6 ′ face each other with a gap therebetween.
[0004] As shown in FIG. 6 , the related-art linear motor has such a mechanism that a single moving member is driven by a single linear motor mover 1 ′ (see, e.g., JP-A-2000-303828).
[0005] More specifically, the related-art linear motor is configured as follows for the purpose of facilitating connection with regard to crossover lines and neutral points of the armature coils, and increasing thrust per unit volume of a core block. That is, the linear motor includes an armature which faces permanent magnets for forming the magnetic field, with a magnetic gap therebetween. The armature is formed from core blocks divided into a plurality of pieces in the thrust direction, and an armature coil. The armature coil, which is wound around each of the core blocks, is configured such that a start-of-winding portion and an end-of-winding of the armature conductor are connected to a wiring substrate that has a wiring pattern.
[0006] However, even the above-mentioned linear motor that can increase thrust has a limit.
[0007] In consideration of a case where a linear motor is employed for driving a large machine tool or the like, required thrust for some machine tools is as high as 40,000 N. In this case, magnetic attraction between magnets and a core is as high as 12,000 N (12 t). However, in an attempt to obtain the required thrust by means of the linear motor as shown in FIG. 6 provided with a single armature, an increase in thrust or heat development by the armature gives rise to a problem of cogging, whereby the linear motor sometimes fails to drive such large machines.
[0008] If, a linear motor is designed on an assumption of including a single armature, a mover (armature) weighs 250 kg or more, thereby exacerbating a handling problem, and like problems. In addition, increase in the attractive force of magnets in the motor leads to a problem that assembly of magnets becomes time-consuming.
[0009] Furthermore, in a case of failure, cost incurred by damage also increases.
[0010] The present invention has been conceived to solve the above problem, and aims at providing an inexpensive, serial configuration linear motor which is capable of driving a large machine, is capable of canceling cogging force, offers facilitated assembly of movers, and is capable of providing thermal protection of the movers with ease.
DISCLOSURE OF THE INVENTION
[0011] To solve the above problem, an invention of claim 1 related to a serial configuration linear motor is constituted of a plurality of movers, each of which is formed from an armature having a polyphase balancing winding, and a stator having a permanent magnet or a secondary conductor. The linear motor is characterized in that the plurality of movers are disposed on the single stator so as to face each other with a gap therebetween; and the polyphase balancing windings of the respective movers are connected in series.
[0012] An invention of claim 2 is the serial configuration linear motor defined in claim 1 , further characterized in that the plurality of movers are of a single configuration.
[0013] An invention of claim 3 is the serial configuration linear motor defined in claim 1 or 2 , further characterized in that connecting terminals are provided on front ends and rear ends of the movers, and multilayered winding terminals of a rear-end terminal in a final mover are short-circuited with each other (i.e., a neutral-point processing is applied thereto).
[0014] An invention of claim 4 is the serial configuration linear motor defined in claim 1 or 2 , further characterized in that, in a condition where the number of phases of each of the plurality of movers is set to three and the number of movers is set to an integral multiple of three, phases of the respective movers are shifted from each other by 120° or 240° in electrical angle, and connecting terminals on the front ends and rear ends in the respective movers are connected while being shifted by 120° or 240°.
[0015] An invention of claim 5 is the serial configuration linear motor defined in claim 1 or 2 , further characterized in that a thermister is incorporated in each of the plurality of movers; and external terminals are provided on the front and rear ends of each of the movers so as to connect all the thermisters in series.
[0016] As described above, by virtue of disposing a plurality of movers on a single stator and connecting the polyphase balancing windings in the movers in series, the present invention provides a serial configuration linear motor which can drive a single moving member.
[0017] In addition, by virtue of series connection of the movers, generation of cyclic current in each of the movers, which is generated when the movers are connected in parallel and as a result of slight phase shifts, can be prevented; and an arrangement where linear movers having different thrust capacities are combined is enabled.
DETAILED DESCRIPTION OF THE INVENTION
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a schematic perspective view of a linear motor according to an embodiment of the invention;
[0019] FIG. 2 is an example of connection with regard to three-phase balancing windings applied to each linear mover in a linear motor mover group of FIG. 1 ;
[0020] FIG. 3 is a top external view of the linear mover of FIG. 2 ;
[0021] FIG. 4 is a diagram showing a connection relationship between movers in a case where three movers of FIG. 2 are connected in series;
[0022] FIG. 5 is a view showing a relationship between cogging thrust and cogging cancellation of the movers; and
[0023] FIG. 6 is a perspective external view of a related-art linear motor.
BEST MODE FOR CARRYING OUT THE INVENTION
[0024] Hereinafter, an embodiment of the invention will be described by reference to the drawings.
[0025] FIG. 1 is a schematic perspective view of a linear motor according to the embodiment of the invention.
[0026] In the drawing, reference numerals 1 a to 1 c denote a first linear motor mover group constituted of armatures; 1 d to 1 f denote a second linear motor mover group constituted of the same; 2 A denotes a power amplifier for driving the first linear motor mover group; 2 B denotes another power amplifier for driving the second linear motor mover group; 6 A denotes a stator where the first linear motor group is placed; and 6 B denotes another stator where the second linear motor group is placed.
[0027] As shown in the drawing, the linear motor is an example where two mover groups constituted of the first mover group 1 a to 1 c on'the stator 6 A, which is on the left side in the drawing, and the second mover group 1 d to 1 f on the stator 6 B, which is on the right side in the drawing, are respectively driven by the two power amplifiers 2 A and 2 B serving as drivers.
[0028] FIG. 2 is an example of three-phase balancing windings applied to each linear mover in the linear motor mover group of FIG. 1 .
[0029] The drawing shows that a single linear mover has terminals U, V, and W at a front end (on the left side in the drawing) and terminals X, Y, and Z at a rear end (on the right side in the drawing). Two single-phase coils (RU 1 , RU 2 ) of the three-phase winding are connected in series between the terminals U and X. Two other single-phase coils (RV 1 , RV 2 ) of the three-phase winding are connected in series between the terminals V and Y. The remaining two single phase coils (RW 1 , RW 2 ) of the three-phase winding are connected in series between the terminals W and Z.
[0030] In addition, two thermisters 41 (THa) and 42 (THb) are connected in series between a terminal A on the front end of the single linear mover and a terminal “a” on the rear end thereof. The thermister 41 is disposed between the terminals U and V; and the other thermister 42 is disposed between terminals V and W. Accordingly, the thermisters 41 and 42 detect the respective temperatures.
[0031] In addition, a bypass line for the thermisters is also connected between a terminal B on the front end and a terminal “b” on the rear end.
[0032] Furthermore, an earth cable connected to an armature core (not shown) is connected between a terminal E on the front end and a terminal “e” on the rear end.
[0033] FIG. 3 shows a top external view of the linear mover of FIG. 2 .
[0034] In the drawing, reference numeral 1 denotes the linear mover as a single article; 51 denotes a front-end terminal (on the left side in the drawing); and 52 denotes a rear-end terminal (on the right side in the drawing).
[0035] Within the components, as having described by reference to FIG. 2 , two U-phase coils are connected in series between the terminals U and X, two V-phase coils are connected in series between the terminals V and Y, and two W-phase coils are connected in series between the terminals W and Z. In addition, two thermisters are connected in series between the terminals A and “a.” A bypass line for the thermisters is connected between the terminals B and “b.” An earth cable, connected to the armature core (not shown), is connected between the terminal E on the front end and the terminal “e” on the rear end.
[0036] FIG. 4 shows a relationship in connection between movers in a case where three movers of FIG. 2 are connected in series.
[0037] The respective movers 1 a to 1 c are disposed so as to be offset by an electrical angle “n,” which is an integral multiple of 240° therebetween.
[0038] Power is fed from the outside to the terminals U, V, and W of the front-end terminal 51 a in the mover 1 a on the front end.
[0039] Within the mover 1 a , as having been described by reference to FIG. 2 , the terminal U is connected to the terminal X of the rear-end terminal 52 a by way of the phase coils Ru 1 and Ru 2 connected in series. The terminal V is connected to the terminal Y of the rear-end terminal 52 a by way of the phase coils Rv 1 and Rv 2 connected in series. The terminal W is connected to the terminal Z of the rear-end terminal 52 a by way of the phase coils Rw 1 and Rw 2 connected in series.
[0040] Next, the terminals X, Y, and Z of the rear-end terminal 52 a in the mover 1 a are respectively connected to the terminals U, V, and W of the front-end terminal 51 b in the subsequent mover 1 b . However, within the mover 1 b , the terminal U is not connected to the phase coils Ru 1 and Ru 2 , to which the terminal U in the mover 1 a is connected; instead, the terminal U in the mover 1 b is connected to the terminal X of the rear-end terminal 52 b by way of the phase coils Rv 1 and Rv 2 , which are adjacent to the phase coils Ru 1 and Ru 2 and shifted by 120° in electrical angle therefrom. Similarly, the terminal V is connected to the terminal Y of the rear-end terminal 52 b by way of the phase coils Rw 1 and Rw 2 , which are adjacent to the phase coils Rv 1 and Rv 2 and shifted by 120°, therefrom; and the terminal W is connected to the terminal Z of the rear-end terminal 52 b by way of the phase coils Ru 1 and Ru 2 , which are adjacent to the phase coils Rw 1 and Rw 2 and shifted by 120° therefrom.
[0041] The terminals X, Y, and Z of the rear-end terminal 52 b in the mover 1 b are respectively connected to the terminals U, V, and w of the front-end terminal 51 c in the subsequent@ mover 1 c . However, within the mover 1 c , the terminal U is not connected to the phase coils. Rv 1 and Rv 2 , to which the terminal U in the mover 1 b is connected; instead, the terminal U in the mover 1 c is connected to the terminal X of the rear-end terminal 52 c by way of the phase coils Rw 1 and Rw 2 , which are adjacent thereto and shifted by 120° in electrical angle therefrom. Similarly, the terminal V is connected to the terminal Y of the rear-end terminal 52 c by way of the phase coils Ru 1 and Ru 2 , which are adjacent to the phase coils Rw 1 and Rw 2 and shifted by 120° therefrom; and the terminal W is connected to the terminal z of the rear-end terminal 52 c by way of the phase coils Rv 1 and Rv 2 , which are adjacent to the phase coils Ru 1 and Ru 2 and shifted by 120° therefrom.
[0042] As described above, orders among the phases Ru, Rv, and Rw of the respective phase windings in the movers 1 a to 1 c are connected by way of connecting lines such that, when the order in the first mover 1 a is Ru-Rv-Rw, that in the second mover 1 b is Rw-Ru-Rv and that in the third mover 1 c is Rv-Rw-Ru.
[0043] The terminals X, Y, and Z of the rear-end terminal 52 c in the third mover 1 c , which serves as the final mover, are short-circuited, thereby forming a neutral point.
[0044] Furthermore, terminals on the front and rear of the respective thermisters in the movers 1 a to 1 c are also connected respectively, and the terminals “a” and “b” of the third mover 1 c , which serves as the terminal mover, are short-circuited. Consequently, all the thermisters are connected in series.
[0045] Accordingly, even when an anomalous temperature arises in any one of the phase windings in any one of the movers, the anomaly can be detected appropriately and the mover can be thermally protected.
[0046] As described above, by means of disposing and connecting the respective movers 1 a to 1 c so as to be offset by an electrical angle “n,” which is an integral multiple of 240° (or 120°), therebetween, cogging force can be cancelled.
[0047] FIG. 5 is a view showing a relationship between cogging force and travel distance in cogging cancellation.
[0048] In the drawing, the vertical axis indicates cogging thrust (N), and the horizontal axis indicates travel distance.
[0049] For instance, cogging thrusts by the movers 1 a to 1 c shown in FIG. 1 are such that magnetic circuit imbalance between the front-end and rear-end terminals generates cogging thrusts of sine curves which are respectively shifted in terms of phases and along the horizontal axis.
[0050] However, as described by reference to FIG. 4 , when the phases of the respective movers 1 a to 1 c are shifted by 240°, the respective cogging thrusts cancel each other. Accordingly, as shown in data on total cancellation of FIG. 5 , the variation can be suppressed to a small value.
INDUSTRIAL APPLICABILITY
[0051] As described above, the serial configuration linear motor according to the invention is advantageous as a device for, for instance, driving a single moving member by means of a plurality of linear motor movers. | A linear motor including a plurality of movers ( 1 a to 1 c ), each of which is formed with an armature having a polyphase balancing winding (Ru to Rw), and a stator having a permanent magnet or a secondary conductor is configured such that the plurality of movers ( 1 a to 1 c ) are disposed on the single stator; and the polyphase balancing windings (Ru to Rw) in the respective movers ( 1 a to 1 c ) are connected in series Accordingly, there can be obtained an inexpensive linear motor which is capable of driving a large machine, which is capable of canceling cogging force, which offers facilitated assembly of movers, and which can provide thermal protection of the movers with ease. | 7 |
FIELD OF THE INVENTION
The present invention relates to a method of language instruction, and a system and device for implementing the method. In particular, the present invention relates to a method for learning a language using a voice portal.
BACKGROUND INFORMATION
Learning a new language may be a difficult task. With increasing globalization, being able to communicate in multiple languages has also become a skill that may provide an edge, including, for example, in career advancement. The quality of the experience of visiting a country, whether for pleasure or business, may be enhanced by even a rudimentary knowledge of the local language. There are various ways to learn a language, including by reading books, taking classes, viewing internet sites, and listening to books-on-tape.
It is believed that an important aspect of learning a language is learning correct pronunciation and language usage. Practicing pronunciation and usage may be a critical aspect of properly learning a language.
It is believed that available language learning tools may have various disadvantages. For example, learning from a book or books-on-tape is not an interactive process, and therefore the student may fall into the habit of incorrect usage. Attending a class may be helpful, but it may also be inconvenient because of a busy schedule, especially for professionals. Also, students may lose interest in learning if they feel that they are not able to cope with the pace of the class.
A tool that teaches pronunciation and usage, and which can be used at the student's own leisure, would be very convenient and useful. It is therefore believed that there is a need for providing a method and system of providing convenient, effective and/or inexpensive language instruction.
SUMMARY OF THE INVENTION
An exemplary method of the present invention is directed to providing teaching pronunciation which includes communicating by a voice portal server to a user a model word and detecting a response by the user to the voice portal server. The exemplary method also includes comparing the response word to the model word and determining a confidence level based on the comparison of the response word to the model word, and comparing an acceptance limit to the confidence level and confirming a correct pronunciation of the model word if the confidence level one of equals and exceeds the acceptance limit.
An exemplary system of the present invention is directed to providing a system which includes a voice portal, a communication device adapted to be coupled with the voice portal server, and an application server adapted to be electrically coupled with the voice portal. In the exemplary system, the voice portal compares at least one word spoken by a user into the communication device with a phrase provided by the application server to determine a confidence level.
An exemplary method of the present invention is directed to providing for a language teaching method which includes communicating a prompt to a user by a voice portal, detecting a response by the user to the voice portal, parsing the response into at least one uttered phrase, each of the at least one uttered phrase associated with a corresponding at least one slot. The exemplary method further includes comparing each of the at least one uttered phrase associated with the corresponding at least one slot with at least one stored phrase, the at least one stored phrase associated with the corresponding at least one slot, and determining a confidence level based on the comparison of each uttered phrase with each stored phrase corresponding to the at least one slot. The exemplary method further includes comparing an acceptance limit to each confidence level, the acceptance limit associated with each stored phrase, and confirming that at least one uttered phrase corresponds to each stored phrase if the confidence level of one equals or exceeds the associated acceptance limit.
The exemplary method and/or system of the present invention may provide a user accessible service which may be used at the user's convenience, at any time. The exemplary system may track a user's knowledge, experience, and progress. The exemplary system may check on the pronunciation of words/phrases/sentences, as well as identify the correct word usage with an incorrect pronunciation. The exemplary system may also assess a user's performance (such information may be used to decide to go to the next level), and may make scheduled calls to improve a user's interaction skills and readiness in the foreign language. The user may be able to decide to be trained on specific topics or grammars (such as, for exemple, financial or technical).
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows an exemplary embodiment of a system of the present invention showing a user, a voice portal and a database.
FIG. 2 shows an exemplary method according to the present invention, in the form of a flow chart demonstrating a dialogue structure for a user calling the service.
FIG. 3 shows an exemplary method according to the present invention, in the form of a flow chart demonstrating a test environment that provides an interactive learning tool for the users to help improve their language skills in the specified language.
FIG. 4 shows schematically a virtual classroom including components of the voice portal server, interactive units and the user.
FIG. 5 shows an exemplary response parsed into slots and showing various possible uttered phrases.
DETAILED DESCRIPTION
The voice portal may be used as an interactive tool to learn a new language. Speech recognition and playback features may enable the system to provide a simulated, classroom-like environment to the user. According to an exemplary method of the present invention, the method provides an interactive tool that can correct pronunciation and grammar and that can be accessed at any time.
FIG. 1 shows a schematic diagram of the system. A voice portal (also referred to as a voice portal server) 12 may be used to recognize proper pronunciation and may be used as an interactive language instruction tool. FIG. 1 shows the voice portal 12 which operates as an interactive tool for learning a language. A user 10 may call the voice portal 12 . The voice portal 12 may then pull up the profile of the user 10 and begin providing the user 10 with a corresponding tutorial.
The user 10 may use a telephone 11 to access the voice portal 12 by calling a telephone number. Alternative methods for the user 10 to access the voice portal 12 may include the use of a personal computer. The voice portal 12 may access a database 13 , which may include a pool of valid, stored phrases (alternatively referred to as grammar files) for various languages, including different dialects within each language. The database 13 may also include different lesson plans depending on the student goals (for example, traveling, conversation, business, academic, etc.). The database 13 may also include a record of the previous lessons presented to user 10 , as well as a progress report which may include areas of strengths and weaknesses.
An exemplary system of the present invention may introduce the use of the voice portal 12 as a tool for learning specific languages. The system may provide a structured learning process to the user 10 through a simple call to the voice portal 12 . This instruction may include tutorials and tests to provide the user 10 with a class-like environment, and may provide the user 10 with the flexibility to take lessons and practice by calling the voice portal 12 at any time.
The voice portal 12 may include a server connected to the telephone system or another communication network to provide speech recognition and text-to-speech capabilities over the telephone 11 or another communication device. The voice portal 12 may be used to provide different types of information, including, for example, news, weather reports, stock quotes, etc. The voice portal 12 may also maintain profiles of the user 10 , so that the user 10 can access E-mail, a calendar, or address entries.
An exemplary system of the present invention uses the voice portal 12 to replicate a language class with pseudo student-teacher interaction. The voice portal 12 operates as a “teacher” to correct the student (the user 10 ), by providing the user 10 with a method of immediate feedback on correctly pronouncing words and correctly using grammar. The voice portal 12 can also store a profile of the user 10 . By keeping track of the sessions of the user 10 , the voice portal 12 may evaluate performance and increase the complexity of the lessons depending on the performance of the user 10 . An exemplary system of the present invention may also recap or summarize the previous sessions if the user 10 is accessing the voice portal 12 after some time interval or if the user 10 requests a review.
FIG. 2 shows a dialogue structure that a user may experience when calling the service and initiating an instructional session. FIG. 2 shows an arrangement or configuration in which the user calls the voice portal 12 and selects, within a dialog setting, the language (for example, “French,” “Spanish” or “German”) and the level (for example, “basic”, “intermediate” or “advanced”). The voice portal 12 recognizes these commands and provides the user 10 with a relevant lesson in the selected language.
The flow of FIG. 2 begins at start 21 and proceeds to action 22 , in which the system initiates the session. The action 22 may include answering a telephone call to the system, and may therefore represent the initiation of contact with the system. The voice portal 12 may answer the phone call or other contact with a greeting of, for example, “Welcome to the Language Learning Center. From your profile I see that you are currently on French level intermediate. Do you want to continue learning French?” Next, in response 23 , the user responds to the interrogatory of the system. If the user responds “yes,” then in action 24 , the system may offer to review the student's progress by, for example, asking “Do you want to recap your previous session?” After action 24 , in response 25 , the user responds to the interrogatory of the system, and if the user responds “yes,” then in action 26 , the system begins to review the lesson by, for example, “Recapping our previous sessions . . . ” After action 26 , circle 27 may represent the beginning of a review session. If the user responds with a “no” in response 25 , then in action 28 the system begins instruction by, for example, providing the message “Continuing intermediate level French class . . . ” From action 28 , circle 30 may represent the beginning of an instruction session. An example of this instruction session is shown in greater detail in FIG. 3 . If the user 10 responds with a “no” in response 23 , then in action 29 , the system may interrogate the user 10 by providing the message, for example, “Please select a language, for example, German or Spanish.” After action 29 , in response 31 , the user 10 responds to the interrogatory. If the user 10 responds “German”, then in action 32 , the system interrogates the user 10 by, for example, providing the instructional message “Please select the level of instruction, for example, beginner, intermediate, or advanced.” From action 32 , in response 33 , the user 10 responds to the interrogatory. If the user responds “advanced”, then in action 34 , the system may begin instruction by providing, for example, the message: “Starting advanced level German class.” From action 34 , circle 35 may represent the beginning of an instruction session. Alternatively, in response 31 , the user may respond “Spanish”, which leads to circle 36 , which may represent the beginning of another instructional session. Additionally, in response 33 , the user may respond “beginner”, which leads to circle 38 , or “intermediate”, which leads to circle 39 . Each of circle 38 and circle 39 may represent the beginning of a different instructional session.
FIG. 3 shows an exemplary test environment to provide an interactive learning tool for users to aid in improving their language skills in the specified language. Specifically, FIG. 3 starts with circle 37 , which may represent the same circle 30 from FIG. 2 , or may represent another starting point. Proceeding from circle 37 to action 40 , the system begins instruction by providing, for example, the message: “Scenario: you meet someone for the first time in a party, how would you greet them, in French.” After action 40 , in response 41 , the user 10 responds. After response 41 , in action 42 , the user response is checked against possible answers. In action 42 , the system may access the database 13 . After action 42 , in action 44 , the system determines a confidence level based on the comparison. Next, at decision-point 45 , the system determines whether the confidence level is equal to or greater than an acceptance limit associated with each possible answer. If the confidence level is greater than or equal to the acceptance limit, then action 46 is performed, which indicates to the system to continue with the next question. After action 46 , circle 47 , may indicate a continuation of the instruction session, including additional scenarios, vocabulary and pronunciation testing, or comprehension skills.
If the response at decision-point 45 is negative, which indicates that the confidence level is less than the acceptance limit, then in action 48 , the system informs the user 10 that the response was unsatisfactory. Following action 48 , in question 49 , the system queries whether the user 10 wants to hear a sample correct response. If the user responds affirmatively, then in action 50 , the system provides a sample correct response. Following action 50 , in question 51 , the system queries the user 10 if the question is to be repeated. If the user responds in the negative, then in action 52 , the system prompts the user 10 by providing, for example, the message “Then try again”, and returns to action 41 .
If the response to question 49 is negative, then the flow may proceed to question 51 , and if the response to question 51 is affirmative, then action 40 is performed.
When the user 10 reaches a certain point in the language course, the system may conduct a test to assess the user's progress. Depending on the results of the assessment test, the system may recommend whether the user 10 should repeat the lesson or proceed to the next level.
Another scenario is that the user 10 may practice by repeating the word until the system recognizes the word, or the system may repeat the word after each attempt by the user 10 to pronounce correctly the word until the user correctly pronounces the word. In the pseudo-classroom, the correction of pronunciation and language nuances may be made immediately by the voice portal. For example, the following dialogue may be part of the language instruction:
System: Please say “Telegraphie”<tele'gra:fi>
User: <tele'gra: phe>
System: That is an incorrect pronunciation, please say it again. <tele'gra:fi>.
User: <tele'gra:fi>
System: That's right! Let's go to the next word.
Additionally, the system may test the user 10 in pronouncing groups of words. Term shall mean in the context of this application both single words and groups of words.
FIG. 4 shows an exemplary architecture of a combined voice portal 12 and web portal 54 . The user 10 may set a personal profile via a web portal 54 . A geo (geography) server 56 may contain country specific or location specific information, E-mail server 55 may send and receive E-mails in the language being learned, the database 13 may include the user profile, language information and correct and incorrect pronunciations. The voice portal 12 may be the main user interface to learn and practice the language skills. An application server 57 may control access to the geo-server 56 , E-mail server 55 and the database 13 from the voice portal 12 and the web portal 54 . The web portal 54 may be connected to a personal computer 59 via the Internet 60 , or another communication network. The web portal 54 may be coupled or connected to the personal computer 59 via the Internet 60 , or other communication network. The voice portal 12 may be connected or coupled to the telephone 11 (or other communication device) via a telephone system 61 , or other communication network. The geo-server 56 , the E-mail server 55 , the database 13 , the voice portal 12 , the application server 57 , and the web portal 54 may be collectively referred to as a language learning center 58 . Alternatively, the user 10 may access the language learning center 58 without the telephone 11 by using a personal computer 59 having an audio system (microphone and speakers). The user 10 may also access the language learning center 58 without a personal computer 59 by using only the telephone 11 , or some other suitably appropriate communication device.
The geo-server 56 may provide location specific information to the user 10 by identifying the location of the user 10 through a GPS system, a mobile phone location system, a user input, or by any other suitably appropriate method or device. The location specific information provided by the geo-server 56 may include the local language, dialect and/or regional accent. For example, the user 10 may call voice portal 12 , and ask the question: “How do I say ‘where can I get a cup of coffee here?” The geo server 56 may locate the user 10 by a mobile phone location system or a GPS system integrated in the telephone 11 . The geo-server 56 may identify the dominant language and any regional dialect for the location of the user 10 . This information may be provided to the application server 57 to assist in accessing the database 13 . Thus, the voice portal 12 may provide the user 10 via telephone 11 with the foreign language translation of the phrase “Where can I get a cup of coffee?” This information may be provided in the local dialect and accent, if any, and the user 10 may then be prompted to repeat the phrase to test the user's pronunciation skills.
E-mail server 55 may be used to send E-mails to the user 10 for administrative purposes (such as, for example, to prompt the user 11 to call the voice portal 12 for a new lesson), or to teach and/or practice reading and/or writing in a foreign language.
Voice recognition can be divided into two categories: dictation and dialogue-based. Dictation allows the user to speak freely without limitation. As a consequence, however, voice recognition of dictation may require a large amount of processing power and/or a large set of sound-files/grammar-files, possibly pronounced by the user, to effectively identify the spoken word. There may be few algorithmic limitations on normal speech to aid in the identification of the spoken word, and these limitations may be limited to a few grammar rules. On the other hand, a dialogue-based system may be implemented with less processing power and/or fewer or no sound samples from the user. A dialogue-based system may parse a response into grammatical components such as subject, verb and object.
Within each of the parsed components, a dialogue-based system may have a limited number (such as, for example, 15) stored sound files, with each stored sound file associated with a different word. Thus, a dialogue-based system may reduce the level of complexity associated with voice recognition considerably. Additionally, each stored sound file, each parsed grammatical component, or each user response may have an associated acceptance limit, which may be compared to a confidence level determined by the dialogue-based system when associating a particular sound with a particular stored sound file. A high acceptance limit may require a higher confidence level to confirm that the word associated with that stored sound file was the word spoken by the user. This concept may be expanded by using incorrect pronunciation stored sound files. Incorrect pronunciation stored sound files may include the incorrect pronunciation of the word.
The system may be designed so that a particular uttered sound does not lead to confidence levels for two different sounds that may exceed the respective acceptance limits for the different stored sounds. In other words, the prompts from the system to the user 10 may be designed so that acceptable alternative responses would have a low possibility of confusion.
Limits may be provided by using slots, which may be delimited using recognized silences. For example:
“The grass | is | green.”
slot 1 | slot 2 | slot 3
The system may be able to correct the user 10 , if the user 10 uses a wrong word in slot 2 , such as, for example, “are” instead of “is”. There may be other solutions to correct grammatical “ordering” mistakes (such as, for example, “The grass green is.”). The uttered phrase may be compared for one slot with stored phrases associated with other slots for confidence levels that exceed acceptance limits. If any confidence level exceeds an acceptance limit for an uttered phrase compared with a stored phrase for another slot, then an ordering mistake may be identified. The system may then inform the user 10 of the ordering mistake, the correct order and/or the grammatical rule determining the word order.
For example, if an answer is expected in the form “You | are | suspicious!” (in which a “|” represents a slot delimiter) and the answer is “Suspicious you are”, then the slots have to have at least the following entries >slot 1 : “you, suspicious”, slot 2 : “are, you”, slot 3 : “suspicious, are” <for the two instances to be recognized. While the combination 111 would be the right one, the system would tell the user 10 , if it recognizes 222 , that the user 10 has made an ordering error. The system may also recognize other combinations as well, such as, for example, 122 if the user stutters, 211 , and other mistakes, and could inform the user 10 as necessary.
The application server 57 may manage the call, application handling, and/or handle database access for user profiles, etc.
A pool of stored phrases is defined herein as an edition of words recognizable by the system at a given instance, for example “grass, tree, sky, horse, . . . ” For each slot, there can be a different pool of stored phrases. There is an expected diversification of words in each slot, for example:
slot 1 | slot 2 | slot 3
The grass is green.
Is the grass green?
A more subject-oriented example may be types of greetings, for example:
How are you?
Nice to meet you!
I have heard so much about you!
Aren't you with Bosch?
The speech recognition algorithm may recognize silences or breaks and try to match the “filling” (that is, the uttered phrases) between such breaks to what it finds in its pool of stored phrases. The system may start with recognizing “The”, but since this is not in slot 1 , the system may add the next uttered phrase (“grass”) and try again to find a match, and so on. The developer may need to foresee all possible combinations of answers and feed them into the grammar. Even a whole sentence may be in one slot (such as, for example, a slot representing “yes,” “That is correct!”, “That's right!”, “Yepp”, etc.)
With respect to mispronounced entries, a recognition engine may be capable of handling user-defined stored sounds. In those stored sounds, the mispronounciation must be “defined”, that is, a machine readable wrongly pronounced word must be added (such as, for example, if “car” is the expected word, the pronounciation of “care” or “core” may be used, possibly along with other conceivable mispronunciations). For the system to be able to recognize wrongly pronounced words, those mispronounciations must be known to the system. Otherwise the system may reject them as “garbage” in the best case or interpret them as something else and possibly deliver the wrong error message.
Therefore, in operation, the system may provide a scenario to only allow for a few possible subjects, restricted to what is predefined in the pool of stored sounds.
If a word is grammatically required, it can be made mandatory, that is, there would be a slot for it (such as, for example, to differentiate between wrong pronounciations or even wrong words). Alternatively, the word can be optional (such as, for example, “Grass is green” or “The grass is green”). If the word is optional, there would be no need to reserve a slot. The word may be marked as optional in the “grass” slot. One way to mark a word as optional would be to use an entry like “?the grass”. The question mark in front of “the” makes it optional for the recognition engine. Different markings for optional words are also possible.
An exemplary parsed response is shown in FIG. 5 . In FIG. 5 , a “?” in front of words indicates they are optional (other recognition engines accept [ ] or other ways to mark optional words). The system query might be: “Please identify the objects around you with their color!”
Valid responses may include:
The grass is yellow.
The grass is green.
That big tree is brown.
This small cat is yellow.
Invalid user responses may include:
That tree is brown.
That small dog is yellow.
The system may reject some responses later on because of context, or language invalidity. For instance:
The cat is green. That big tree is blue.
In this case, the recognition engine may recognize what the user has said, but the dialogue manager may reject this as an invalid response (although it might be pronounced correctly and semantically correct).
In particular, FIG. 5 shows response 62 divided into slots 63 , 64 , 65 , 68 . Each of slots 63 , 64 , 65 , 66 has at least one associated valid response. For instance, slot 64 has valid responses 67 , 68 , 69 , 70 . Slot 65 has valid response 80 . Valid responses may have one word (such as, for example, valid response 67 has “grass”), or more than one word (such as, for example, valid response 68 has “big tree”). Additionally, valid responses may include optional word delimiters 81 . Optional word delimiter 81 indicates that the word following optional word delimiter 81 in the valid response may be present or may be absent.
The exemplary embodiments and methods of the present invention described above, as would be understood by a person skilled in the art, are exemplary in nature and do not limit the scope of the present invention, including the claimed subject matter. | A method of teaching pronunciation is provided which includes communicating by a voice portal server to a user a model word and detecting a response by the user to the voice portal server. The method also includes comparing the response word to the model word and determining a confidence level based on the comparison of the response word to the model word. The method further includes comparing an acceptance limit to the confidence level and confirming a correct pronunciation of the model word if the confidence level one of equals and exceeds the acceptance limit. | 6 |
This application is a division of application Ser. No. 669,440 filed Mar. 13, 1991, now abandoned, which in turn is a continuation-in-part of Ser. No. 479,013 filed Feb. 12, 1990, now U.S. Pat. No. 5,013,371.
TECHNICAL FIELD
This invention relates to a hard austenitic stainless steel screw which is excellent in corrosion resistance and a method for manufacturing the same
PRIOR ART
Generally an austenitic stainless steel is higher in corrosion resistance against acid or salt compared with a carbon steel. However, in surface hardness and strength, it is inferior to the carbon steel. Therefore, it is not proper to use this stainless steel for a screw which requires the ability to tighten to an iron-based plate by self-tapping, such as a tapping screw, a self-drilling screw and a dry wall screw. For this purpose, plated carburized iron articles or 13 Cr stainless steel articles are used. It is pointed out as some drawbacks that these articles are not only inferior in oxidation resistance (rust resistance) to the austenitic stainless steel articles but also are weak in their tightening function due to corrosion of their base material by acid rain which is one of the big environmental problems in these days. In this aspect, the austenitic stainless steel articles are far superior in acid resistance. Accordingly the inventors provided a technology for maintaining the tapping property as well as iron articles by nitriding-hardening the austenitic stainless steel (Japanese Patent Application No. 177660/1989). According to the technology, a hard layer can be formed around the periphery of the stainless steel screw by which an iron plate having enough thickness is drilled and tapped. Although most of the surface hard layer (15˜30 μm) in thus obtained hardened layer is ultra-hard, it does not necessarily have enough corrosion resistance in regard to rust and acid resistance to cause rust easily. According to the inventors' research, it was found that a part which is beneath the ultra-hard surface layer had the same corrosion resistance as the stainless steel base material and did not have the problem resulting from acid rain like iron articles and 13 Cr articles. In the aspect of appearance, it is not preferable to change color of a visible part, especially a screw head seen after tightening. To solve these problems, it was proposed to apply the method for nitriding by masking the screw head with copper-plating or the method wherein a screw head part of an austenitic stainless steel is joined with a drill part made of iron carburized material by welding. However, there are the disadvantages that masking partly by copper-plating is troublesome and costly in the former method and plural materials used are costly in the latter method. It is possible to plate with Ni-Zn, Zn or Ni wholely in order to prevent rust resulted from the ultra hard film layer of the nitrided surface. Since most of platings are weak to sulphuric acid, the possibility of generating rust by acid rain can not be excluded, especially for screws used outside. Therefore, plating itself is effective in respect of smoothness and maintaining beautiful appearance, but is not perfect in rust prevention.
SUMMARY OF THE INVENTION
Accordingly, it is the object of the invention to provide a hard austenitic stainless steel screw which has the same drilling, tapping and tightening properties against a steel plate to be drilled as iron articles and its head which is visible after tightening has anti-corrosion property as well as austenitic base material, and a method for manufacturing the same.
To accomplish the above-mentioned purpose, the invention provides a hard austenitic stainless steel screw characterized in that a hard nitrided layer comprising an ultra hard surface layer and an inner hard layer beneath connecting to a core part of the screw is formed on the surface of an austenitic stainless steel screw, a predetermined part of said hard nitrided layer being removed its ultra hard surface layer to be only the inner hard layer connecting to the core part. The invention also includes a method for manufacturing a hard austenitic stainless steel screw comprising steps of holding austenitic stainless steel screw base material in a fluorine- or fluoride-containing gas atmosphere to form a fluorinated layer on the surface, heating the fluorinated screw in a nitriding atmosphere to form the screw surface layer into a hard nitrided layer comprising an ultra hard surface layer and an inner hard layer beneath connecting to a core part of the screw and removing said ultra hard surface layer of a predetermined part of said hard nitrided layer to expose the inner hard layer connecting to the core part.
The "inner hard layer" means a metal composition layer which is about 20% harder than the core part of the stainless steel base material.
During the process of accumulated research for finding a cause of generating rust on a nitrided layer of an austenitic stainless steel screw, the inventors discovered that the nitrided layer had two layers, an ultra hard surface layer and an inner hard layer beneath, that the ultra hard surface layer comprises intermetal compounds such as CrN, Cr 2 N and Fe 2-3 N in metal composition, that the inner hard layer is a solid solution in which N, C, Fe-C are solution with the austenite of the core part. As mentioned before, had an idea that if the ultra hard surface layer is eliminated to expose the inner hard layer beneath the ultra hard surface layer, it is possible to prevent rust without losing substantially most of the surface hardness and strength since rust generates only on the ultra hard surface layer, and reached the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
This invention exposes the inner hard layer beneath connected to a core part by removing an ultra hard surface layer out of nitrided layer formed on the surface of an austenitic stainless steel screw. In general, the ultra hard surface layer has a thickness of 15 to 30 μm and a surface hardness (Hv) of 1200 to 1400, and the inner hard layer has a thickness of 30 to 150 μm and a surface hardness (Hv) of 320 to 650. The inner hard layer is far larger in its surface hardness and almost similar in anti-corrosion resistance to acid and base compared with the austenitic stainless steel which is base material.
In this invention, a screw is made of austenitic stainless steel base material. After nitriding it as mentioned above, only a surface layer (ultra hard surface layer) in the nitrided layer is removed. The way of removing it is conducted chemically or mechanically. In the chemical way the ultra hard surface layer of a predetermined part, for example, a screw head is dipped in strong acid such as HF-HNO 3 , or aqua regia for 10 to 120 minutes. In the mechanical removing way, the part is given a mechanical scouring or the like. In the aspect of removing uniformly, the chemical method is preferable. In addition to the screw head part, it is preferable to remove the ultra hard surface layer of the axis part depending on a screw within the range that the removal does not influence tightening function.
Describing in detail, a hard austinitic stainless steel screw according to the present invention is manufactured as below-mentioned. That is, austenitic stainless steel base material (hereinafter called steel material) is held preliminarily in an atmosphere containing fluorine- or fluoride-containing gas to form a fluorinated layer on the steel surface, then heated in a nitriding atmosphere to remove the fluorinated layer and at the same time, to form the removed surface (surface layer of the steel material) into a nitrided layer. An ultra hard surface layer in the formed nitrided layer is removed to prevent generating rust.
The term "fluorine- or fluoride-containing gas", as used in the above-mentioned pretreatment prior to nitriding, means a dilution of at least one fluorine source component selected from among NF 3 , BF 3 , CF 4 , HF, SF 6 and F 2 contained in an inert gas such as N 2 . Among these fluorine source components, NF 3 is most suitable for practical use since it is superior in reactivity, ease of handling and other aspects to the other. As mentioned previously, in the present invention steel work pieces are held in the above-mentioned fluorine- or fluoride-containing gas atmosphere at a temperature of, for example, 250° to 400° C. in the case of NF 3 , for a preliminary treatment of the steel surface and then subjected to nitriding (or carbonitriding) atmosphere using a known nitriding gas such as ammonia. When F 2 gas alone or a mixed gas composed of F 2 gas and an inert gas, for example, is used as the fluorine- or fluoride-containing gas in a special case, the above-mentioned holding temperature is arranged in the range of 100° C. to 250° C. The concentration of the fluorine source component, such as NF 3 , in such fluorine- or fluoride-containing gas should amount to, for example, 1,000-100,000 ppm, preferably 20,000-70,000 ppm, more preferably 30,000-50,000 ppm. The holding time in such fluorine- or fluoride-containing gas atmosphere may appropriately be selected depending on the steel species, geometry and dimensions of the work piece, heating temperature and so forth, generally within the range of ten or so minutes to scores of minutes.
To be more concrete in illustrating the aforementioned pretreatment and nitriding using fluorine- or fluoride-containing gas, austenitic stainless steel screws, for instance, are cleaned for degreasing and then charged into a heat treatment furnace 1 such as shown in FIG. 1. This furnace 1 is a pit furnace comprising an inner vessel 4 surrounded by a heater 3 disposed within an outer shell 2, with a gas inlet pipe 5 and an exhaust pipe 6 being inserted therein. Gas is supplied made from cylinders 15 and 16 via flow meters 17, a valve 18 and so on and via the gas inlet pipe 5.
The inside atmosphere is stirred by means of a fan 8 driven by a motor 7. Work pieces 10 placed in a metal container 11 are charged into the furnace. In FIG. 1, the reference numeral 13 indicates a vacuum pump and 14 a noxious substance eliminator. A fluorine- or fluoride-containing reaction gas, for example, a mixed gas composed of NF 3 and N 2 , is introduced into this furnace and heated, together with the work pieces, at a specified reaction temperature. At a temperature of 250°-400° C., NF 3 evolves fluorine in the nascent state, whereby the organic and inorganic contaminants on the steel surface of the work piece are eliminated therefrom and at the same time this fluorine rapidly reacts with the base elements Fe and chromium on the surface and/or with oxides occurring on the steel work surface, such as FeO, Fe 3 O 2 and Cr 2 O 3 . As a result, a very thin fluorinated layer containing such compounds as FeF 2 , FeF 3 , CrF 2 and CrF are formed in the metal composition on its the surface, for example as follows:
FeO+2F→FeF.sub.2 +1/2 O.sub.2
Cr.sub.2 O.sub.3 +4F→2CrF.sub.2 +3/2O.sub.2
These reactions convert the oxidized layer on the work surface to a fluorinated layer. At the same time, O 2 adsorbed on the surface is removed therefrom. Where O 2 , H 2 and H 2 O are absent, this fluorinated layer is stable at temperatures up to 600° C. and can presumably prevent the formation of an oxidized layer on the base metal and adsorption of O 2 thereon until the subsequent step of nitriding. A fluorinated layer, which is similarly stable, is formed on the furnace surface as well and minimizes the damage to the furnace material.
The work pieces thus treated with such fluorine- or fluoride-containing reaction gas are then heated at a nitriding temperature of 480° C.-700° C. Upon addition of NH 3 or a mixed gas composed of NH 3 and a carbon source gas (e.g. RX gas) in the heated condition, the fluorinated layer is believed to undergo reduction or destruction by means of H 2 or a trace amount of water to give an active metal base, as shown, for example, by the following reaction equations:
CrF.sub.4 +2H.sub.2 →Cr+4HF
2FeF 3 +3H 2 →2Fe+6HF
Upon formation of such active base metal, active N atoms are adsorbed thereon, then enter the metal structure and diffuse therein and, as a result, a layer (nitrided layer) containing such nitrides as CrN, Fe 2 N, Fe 3 N and Fe 4 n is formed on the surface.
The obtained nitrided layer formed has an ultra hard surface layer 20 and an inner hard layer 21 beneath as shown in FIG. 2 a reference numeral 22 refers to an austenitic stainless steel base material (a core part). In this invention, the ultra hard surface layer 20 of the screw head is removed to expose the inner hard layer 21 on the surface of the screw as shown in FIG. 3. The removal is, for example, conducted by heating HNO 3 -HF solution at about 50° C., dipping a portion of the part, for example, the screw head of the stainless steel screw, therein for about 10 to 120 minutes to melt and remove the ultra hard surface layer and to expose the inner hard layer beneath the ultra hard surface layer. As mentioned before, the ultra hard surface layer has a thickness of 15 to 30 μm. For removal of the layer, it is preferable to dip it in a concentrated etching solution such as aforementioned acid. In some cases, removal may be conducted by scouring with a scourer or the like. The ultra hard surface layer is removed in this way to make the inner hard layer beneath appear. The inner layer has 30 to 150 μm in thickness and is inferior to the ultra hard surface layer, but far superior to stainless steel base material, in surface hardness and strength. Its corrosion resistance is excellent, as good as that of austenitic stainless steel material. Therefore, rust does not generate on the finished piece by acid rain or the like.
That is, the austenitic stainless screw obtained by the above-mentioned method has the same properties as iron articles in tapping and tightening functions, and high corrosion resistance against acid and salt is imported.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a cross-sectional view of a treatment furnace,
FIG. 2 shows a cross-sectional view illustrating a condition of a nitrided layer of a hard austenitic stainless steel screw,
FIG. 3 shows a cross-sectional view illustrating a the ultra hard surface layer removed from an austenitic stainless steel screw,
FIG. 4 shows a condition of a nitrided layer of a dry wall screw head part,
FIG. 5 shows a condition of a nitrided layer of a screw thread part, and
FIG. 6 shows an anode polarization curve diagram.
Following are descriptions of embodiments.
EXAMPLE 1
A cross recessed head dry wall screw of SUS316 stainless steel works (4×25, cross recessed flat head screw) were cleaned with trichloroethylene, then charged into a treatment furnace 1 as shown in FIG. 1, and held at 300° C. for 15 minutes in an N 2 gas atmosphere containing 5,000 ppm of NF 3 , then heated at 530° C., and a nitriding treatment was carried out at that temperature for 3 hours while a mixed gas composed of 50% NH 3 plus 50% N 2 was introduced into the furnace. The work pieces were then air-cooled and removed from the furnace.
The nitrided layer of each work piece thus obtained was uniform in thickness. The surface hardness was 1,250-1,350 Hv while the base material portion had a hardness of 250-260 Hv.
Next, a portion of the uppermost top of the stainless steel screw (the dry wall screw head) was dipped to 10 mm depth in 15% HNO 3 -5% HF solution (50° C.) for 20 minutes and taken out to remove the ultra hard surface layer of the nitrided layer.
The surface hardness of thus obtained stainless steel screw was measured at the head part, in which the ultra hard surface layer is removed, and other parts separately. The results are described in Table 1.
TABLE 1______________________________________ Ultra hard surface layer Removed part (Screw thread part) (Head part)______________________________________Hardness of 1280-1380 380-580the surface(Hv)______________________________________
Upon observing the cross section of the stainless steel screw by photomicrograph, the screw thread part with the ultra hard surface layer intact had two nitrided layers, an ultra hard surface layer and an inner hard layer 21 beneath as shown in FIG. 5, while the head part had its ultra hard surface layer removed and had consists of only one nitrided layer, the inner hard layer 21 as shown in FIG. 4. In FIG. 4, the reference numeral 23 is a cross recess.
Furthermore, corrosion accelerated testing was conducted to thus obtained stainless steel dry wall screw. At first, a screw was cut at 5 mm below from the top of the screw head to divide it into a screw head and others, then a neutral salt spray test was carried out on the two parts. The results are shown in Table 2.
TABLE 2______________________________________Head part surface No change was seen after 500 hoursThread part Rust caused after 4 hours______________________________________
That is, the screw head part having the ultra hard surface layer removed did not form rust and the like after conducting corrosion accelerated test for 500 hours, in contrast to the screw thread part which rusted after 4 hours.
In the stainless steel dry wall screw, the surface hardness and strength of the head part is a little smaller than the thread part, but since surface hardness and strength of the thread part is largely maintained, the screw has self-tapping and drill-tightening properties which are not given by an ordinary stainless steel screw used in a light gage steel.
EXAMPLE 2
A plurality of austenitic stainless steel hexagon head self-drilling screws 4×20 mm (XM7) and SUS 316 plate material (25×35×1 mm t ) were prepared, cleaned with acetone, charged in the furnace shown in FIG. 1, held in an N 2 atmosphere containing 5,000 ppm of NF 3 at 340° C. for 15 minutes. Then the temperature was raised to at 530° C., to hold in N 2 +90% H 2 for 30 minutes, nitrided at that temperature in a 20% NNH 3 +80% RX atmosphere for 5 hours, and taken out of the furnace.
As done for a the drilling screw, a portion from the top of the screw head to 10 mm below the top and as for plate material, the whole part was dipped in aqua regia diluted four times (at the temperature of 45° C.) for 20 minutes, taken out and rinsed. The whole part of the drilling screw was then plated with Ni-Zn for the purpose of smoothness. Screwing property was determined on the basis of JIS screwing test.
The screwing test of the drilling screw was conducted to 20 samples by screwing it into a steel (SPCC) plate having a thickness of 2.3 mm. Consequently, the average screwing time was 2.12 seconds. The times were almost the same as that of what was not dipped from the top of the head part to 10 mm beneath in a HNO 3 -HF solution.
As for the plate material, anode polarization data in 5% H 2 SO 4 solution was taken. The results were shown in FIG. 6. As shown by a curve A, a part of which the ultra hard surface layer was removed by soaking in acid shows almost similar corrosion resistance to a base material surface indicated by a curve B.
EXAMPLE 3
Austenitic stainless steel tapping screws (4×12 mm) and small screws (4×13 mm) were charged into a furnace shown in FIG. 1 and held at 200° C. in an atmosphere containing 1% F 2 for 40 minutes, then heated to 550° C. and nitrided at that temperature in 30% NH 3 +10% CO 2 +60% RX gas atmosphere for five hours. Other treatments were done as well as in Example 2. As a result of conducting weatherability test by CASS test method against those screws, there was no rust caused even after 700 hours, while in cemented iron articles (Ni-Zn plating) and 13 Cr stainless steel articles, white and red rust generated within 24 hours respectively.
EFFECTS OF THE INVENTION
As mentioned above, in the austenitic stainless steel screw according to the present invention, an ultra hard surface layer of a screw head part is removed from its nitrided layer to expose an inner hard layer because the ultra hard surface layer comprising intermetal compounds such as CrN, Cr 2 N and Fe 2-3 N easily causes rust. The inner hard layer comprises a solid solution layer in which N, C and the like are homogeneous with the stainless steel base material is corrosion resistant and has considerably high surface hardness and strength. Therefore, in the austenitic stainless steel screw, the head part does not rust against acid rain and the like. The ultra surface layer of the thread part is not removed, so that the surface hardness and strength are almost the same as those of carbon steel products to allow the screw to have self-tapping and self-tightening properties. In the austenitic stainless steel screw, since base material itself has high corrosion resistance and the inner hard layer is rust preventive, even if rust generates on the ultra hard surface layer in the nitrided layer, it will neither extend to whole part nor influence the strength.
In the invention, since the austenitic stainless steel work piece as mentioned above are held in an atmosphere containing fluorine- or fluoride-containing gas to form a fluorinated layer on the surface prior to nitriding them, and nitrided in that state, a nitrided layer is formed uniformly and deeply to give a hard austenitic stainless steel screw having good surface properties. | This invention allows the surface of an austenitic stainless steel screw surface to be formed into a hard nitrided layer so as to harden and a part such as a screw head which is in contact with outside air is removed its own ultra hard surface layer in the hard nitrided layer by scouring or the like to be rust preventive. Even if the ultra hard surface layer is thus removed, an inner hard layer in the hard nitrided layer is present beneath the surface layer to be able to maintain a hard state of the screw surface. In the method for manufacturing the austenitic stainless steel screw according to the invention, upon forming said hard nitrided layer on the screw surface by nitriding, the austenitic stainless steel screw surface is cleaned with a fluorine- or fluoride-containing gas prior to nitriding. Thereby remained foreign matter, oxidized layer and the like on the screw surface are removed and at the same time the screw surface is activated and so N atoms easily penetrate and diffuse when nitriding to form a uniform nitrided layer. | 5 |
FIELD OF THE INVENTION
[0001] The present invention relates to systems and methods for providing telecommunications.
BACKGROUND OF THE INVENTION
[0002] The following discussion of the background art is intended to place the invention in an appropriate context and to allow the unique characteristics and advantages of it to be more fully understood. However, any discussion of the background art throughout the specification should in no way be considered as an express or implied admission that such prior art is widely known or forms part of common general knowledge in the field.
[0003] Many travellers, especially business people and high ranking executives, are required to remain contactable at all times, even while physically out of the country. This is normally achieved using the ubiquitous mobile or cellular phone, with the roaming service enabled. The roaming service requires the home mobile network to have an agreement in place with the foreign mobile network at the destination. As, in effect, two mobile networks are cooperating to charge the user money, roaming services are infamous for being notoriously expensive. This is particularly true of data and internet related roaming services.
[0004] A partial solution to the problem of exorbitant roaming charges is to purchase a prepaid service at the destination. However, while this alleviates the problem of an expensive roaming service, it does not allow the user to remain contactable at all times.
[0005] Another partial solution is to forward a telephone call from a home mobile number to the destination prepaid number. However, forwarding a call incurs the same cost as making a standard telephone call. Therefore, since each forwarded call is charged as an international direct dial telephone call, there are no cost savings in this approach.
[0006] Accordingly, a need exists for an efficient way by which a user can remain contactable, even while overseas.
SUMMARY OF THE INVENTION
[0007] It is an object of the present invention to overcome or ameliorate one or more of the disadvantages of the prior art, or at least to provide a -useful alternative.
[0008] One embodiment of the invention provides a method of forwarding a call intended for a local telephone number to an overseas telephone number, the method including the steps of:
[0009] selecting a first access number from a pool of available access numbers, the access numbers each providing access to a server;
[0010] redirecting the call from the local telephone number to the first access number; and rerouting the call from the server, accessed via the first access number, to the overseas telephone number.
[0011] One embodiment of the invention provides a system for forwarding a call intended for a local telephone number to an overseas telephone number, the system including:
[0012] an interface for receiving user input, the input including at least the local telephone number;
[0013] a server for selecting a first access number from a pool of available access numbers, the access numbers each providing access to the server; and
[0014] a processor for redirecting the call intended for the local telephone number to the first access number; and
wherein the server is further arranged to reroute the call to the overseas telephone number.
[0016] The server is preferably a VOIP (Voice Over Internet Protocol) server. Preferably, access to the server is defined by a predetermined period of time, and access to the server expires at the end of the predetermined period of time.
[0017] Preferably, in response to access to the server expiring at the end of the predetermined time, releasing the first access number and returning it back to the pool of available access numbers.
[0018] The local telephone number and the overseas telephone number are preferably both mobile telephone numbers, and each access number in the pool of access numbers is preferably a respective landline telephone number.
[0019] One embodiment provides a computer-readable carrier medium carrying a set of instructions that when executed by one or more processors cause the one or more processors to carry out a method as discussed herein.
[0020] One embodiment provides a computer program product for performing a method as discussed herein.
[0021] One embodiment provides a computer system configured to perform a method according as discussed herein.
[0022] One embodiment provides a method substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples.
[0023] One embodiment provides a computer-readable carrier medium substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples.
[0024] One embodiment provides a computer program product substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples.
[0025] One embodiment provides a computer system substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:
[0027] FIG. 1 illustrates a schematic overview of a system for forwarding a call intended for a local telephone number to an overseas telephone number, according to an embodiment of the invention;
[0028] FIG. 2 illustrates a flow chart of a method of forwarding a call intended for a local telephone number to an overseas telephone number, according to an embodiment of the invention;
[0029] FIG. 3 illustrates a flow chart of the call hand off process;
[0030] FIGS. 4 a to 4 d illustrate various screen shots of an interface to the system, according to an embodiment of the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0031] Described herein are various system and methods for forwarding a telephone call and/or a telephonic message (such as an SMS) from a local destination to an overseas destination, wherein at least part of the call is routed through a Voice Over Internet Protocol (VOIP) or like service. Note that throughout this specification, reference will be made to “telephone call” which is intended to have an all-encompassing meaning and refers to any form of telephonic communication, such as but not limited to telephone calls, mobile or cellular phone calls, VOIP calls, short or multimedia messaging service messages, instant messaging over the internet via PCs, smart phones or tablets, and the like.
[0032] In overview, the consumer purchases a period of access and when the purchase is verified, the user is assigned a dynamic direct internal dialing (DID) telephone number, and the user sets up a diversion by forwarding his/her telephone number to the assigned DID number. The DID number provides access to a server, which then converts the telephone call into an appropriate format and routes the telephone over the internet. At the destination, the user purchases or otherwise obtains a local telephone number and supplies the local telephone number to the server. Once this local telephone number information is received, the server automatically sets up a diversion between the server and the local telephone number. Once the purchased period of access expires, the dynamic DID is released back into a pool of DIDs and the diversions are automatically removed. The DID is then ready to be re-assigned to another user.
[0033] Importantly, as will be shown later with reference to FIG. 4 , the process is seamless to the user, who only needs to set up the original diversion and to provide the server with the ultimate destination number.
[0034] More specifically, and according to one embodiment of the invention, there is provided a system of forwarding a call intended for a local telephone number to an overseas telephone number. When the service is activated, a first access number is selected from a pool of available access numbers, the access numbers each providing access to a server. The call is then redirected from the local telephone number to the first access number, which provides access to the server. The call is then rerouted from the server to the overseas telephone number.
[0035] In one embodiment, the server is a VOIP (Voice Over Internet Protocol) server, and access to the server is defined by a predetermined period of time. In an embodiment, the predetermined period of time is a prepaid access period that is selectively purchased by the customer. For example, under one pricing schedule, access is set at $1 per day and the customer nominates the number of days required. Under another pricing schedule, access is set in blocks of time, such as $10 per week, and the customer nominates the period of time required in weekly multiples. Under yet another pricing schedule, a minimum initial period of access is required to be purchased and additional access is added onto the initial minimum period. This is essentially a hybrid pricing schedule of those set out above. For example, the customer is required to purchase an initial minimum block of access of one week for $ 10 , and thereafter can add additional days onto the minimum block for $1 a day. Therefore under this pricing schedule the customer pays $10 for the first 7 days of access and then $1 per day thereafter. Accordingly, for 8 days access the customer pays $11, 9 days for $12, 10 days for $13 and so forth. It will be appreciated by those skilled in the art that many pricing schedules are available and that the examples provided herein are illustrative only. At the end of the predetermined period of time, access to the server expires.
[0036] In an embodiment, the first access number is released responsive to access to the server expiring at the end of the predetermined time. When the first access number is released, it is returned back to the pool of available access numbers, ready to be reassigned to the next user that activates the service.
[0037] Referring now to FIG. 1 , there is schematically illustrated an overview of the system 100 . The embodiment of FIG. 1 shows a plurality of telephone numbers 102 (local and mobile) being forwarded to a server 104 . In this embodiment, the server incorporates several functions. Firstly, the server 104 incorporates a database which is used to verify the user. The server 104 also functions to select the first access number from the pool of access numbers and assign the first access number to the user. Once the user purchases access to the server 104 , the user is free to forward one or more of their local numbers 102 to the server 104 . In this embodiment, the server 104 also implements a VOIP server, which digitises the analogue telephone signals that it receives from local numbers 102 and transmits the digitised signal over the internet 106 to the destination number 108 . For the sake of clarity, the workings of a typical VOIP system are not discussed herein. VOIP is a known technology and assumed knowledge for those skilled in the art.
[0038] In an embodiment, the destination number 108 is a prepaid mobile telephone service which is purchased locally once the user arrives at the destination. However, it will be appreciated by those skilled in the art that the user may already have a suitable service so that purchase of a new prepaid service is unnecessary.
[0039] Once the user obtains a suitable mobile service at the destination, the user informs the server 104 of the destination number 108 so that the VOIP server can route any calls to the local numbers 102 to the correct destination.
[0040] A method 200 according to an embodiment of the invention is illustrated in FIG. 2 . At the start, the user requests diversion of incoming calls to their local number 102 at step 202 , through an interface (such as the interface shown in FIG. 4 , and discussed below). The request is received by the server 104 at step 204 . In this embodiment, the request is accompanied by user login information so that the server can identify the user, and so that the server can determine whether the user has valid access to the server 104 , at step 206 . If the user does not have valid access to the server, the request is rejected at step 208 a.
[0041] If user access is determined to be valid, an access number is selected from a pool of access numbers at step 208 b, and the access number is assigned to the user at step 208 c. At step 210 the user receives the assigned access number and arranges the diversion between the local number 102 and the access number.
[0042] In one embodiment, the user interface, such as the interface discussed with reference to FIG. 4 , automatically configures the diversion between the local number 102 and the access number once the access number is assigned. In other embodiments it is incumbent on the user to configure the diversion the access number is received.
[0043] Once the user obtains a destination number 108 , it is inputted into the interface at step 212 and sent to the server 104 , which receives the destination number 108 at step 214 . The server 104 then receives the destination number 108 at step 216 and configures the diversion between the server 104 and the destination number 108 at step 218 .
[0044] In embodiments discussed, the process is virtually seamless and invisible to the user. The user simply provides the user login information and requests diversion, and steps 204 to 212 are handled on the backend. The next step requiring input from the user is step 214 , in which the user provides the server 104 with the destination number 108 . Once the server 104 receives the destination number 108 , again the diversion is configured on the backend, and is virtually seamless and invisible to the user. The final step having user involvement would be to check that diversion is configured properly. In this regard, in some embodiments, the user would receive a confirmation message when the diversion is properly configured. Typically the confirmation message would be received via the interface. However those skilled in the art would recognise that there are a multitude of ways in which the confirmation message could be provided to the user, such as but not limited to SMS, MMS, telephone call, email, internet messaging, and the like.
[0045] Referring to FIG. 3 , there is illustrated a call hand off process 300 according to embodiments of the invention. The method starts when a call is made to the user's local number, which is received at step 302 . Assuming that diversion process 200 has already been performed, the received call is then diverted to the server at step 304 . The server receives the diverted call at step 306 , and processes the call at step 308 . At the processing step 308 , the server determines the local number that the call was originally meant for, and accesses the user's account based on the local number information to determine whether the user is within a valid access period. Once it is determined that the access period is valid, at step 310 , the server obtains the diversion information from the user's account and the call is diverted to that destination number at step 312 . On the other hand, returning to step 310 , if the access period is not determined to be valid, the call is ended directly.
[0046] At step 314 , if the user answers the call, the user speaks with the caller as normal at step 316 and when the call is finished, it is hung up at step 318 and the process is ended. On the other hand, if the user is not reachable, the call is passed to step 320 which diverts the call to voicemail and the process ends once a voicemail message is recorded. An example will now be described, with particular reference to FIGS. 4 a to 4 d , the example is presented as an illustration of an aspect of one embodiment of the invention, and is presented as an aid to understanding the invention. It should not be interpreted as the only way to carry out the invention, or otherwise limiting in any way.
[0047] According one embodiment of the invention, the server 104 is accessed through an interface 400 , the initial screen of which is shown at FIG. 4 a . In this embodiment, the interface is implemented as an application, or commonly referred to as an “app”, which runs on an Apple® iPhone® 402 , shown conceptually in FIGS. 4 a to 4 d . However, those skilled in the art will appreciate that this is not the only way in which to implement the interface. In particular, the interface may be implemented in a multitude of ways including as an app running on for example the Google® Android®platform, the Microsoft® Windows® Mobile platform, the Blackberry® BB10® platform, the Nokia® Symbian® platform, the Samsung° BADA° platform and the like. Those skilled in the art will also appreciate that the implementation of the interface is not limited to the mobile platforms, but also may be implemented as a software application running natively on a PC or a Mac, or as a web application running in the cloud and accessible through a browser (not shown).
[0048] Referring again to FIG. 4 a , the interface first requires the user to enter their login and password information, at input boxes 404 and 406 respectively, and to press the LOGIN button 408 accordingly. It is assumed, in this embodiment, that the user account information has previously been set up when the user purchased the access to the server 104 . Furthermore, in this embodiment, the login is the user's local number while the password is a password of the user's choosing. The password, in embodiments, may be governed by a number of rules such as a certain number of letters, an alphanumeric combination or any like conditions as will be known to those skilled in the art.
[0049] Once the user presses the LOGIN button 408 , the interface 400 sends the user's login button to the server 104 , via a network such as a mobile data network or via a wifi network. Assuming the user's information can be verified, and that the user has valid access to the server 104 , the interface 400 proceeds to the second screen, shown at FIG. 4 b . As shown in FIG. 4 b , the system has identified that the user is “Travis”, and presents the user with the option of diverting “now” via the DIVERT NOW button 410 . If the user presses the DIVERT NOW button 410 , a “divert now” message is sent to the server 104 . The server then selects an access number from the pool of available access numbers, assigns the access number to the user and returns the access number to the interface 400 . The interface 400 then accesses the underlying menus of the mobile platform, enters the assigned access number and sets up the diversion between the user's mobile phone and the server 104 .
[0050] In this embodiment, as again shown in FIG. 4 b , the user is also offered the option of setting a time and date, by respectively entering the appropriate information into input boxes 412 and 414 , and pressing the SET TIME button 416 . Depressing the SET TIME button 416 performs similar actions to depressing the DIVERT NOW button 410 , except that the SET TIME button 416 defers the actions until the time and date entered in input boxes 412 and 414 .
[0051] This first diversion between the user's local number and the server 104 is, in one embodiment, completed before the user goes overseas. At this point the interface may be paused, and in this embodiment is reactivated when the user reaches his or her destination.
[0052] Once reactivated, the interface proceeds to the third screen, shown at FIG. 4 c . This third screen allows the user to set up the second diversion, which is between the server 104 and the destination number. In embodiments, the user purchases a prepaid service at the destination, typically in the destination airport. The prepaid service will include a destination number, which is entered into input box 418 . The user then depresses DIVERT NOW button 420 , which again sends a “divert now” message to the server 104 via the appropriate network. When the server 104 receives the messages, it arranges for the calls to be diverted to the destination number from the server 104 , thus ensuring calls to user's the local number “follows” the user to the destination number.
[0053] Once both first and second diversions have been set up, the interface 400 proceeds to the final screen, shown as FIG. 4 d . At this stage of the embodiment, the system conducts a final check to confirm that the first and second diversions are in place. In embodiments, a test call may be placed to ensure that the diversion is working. In other embodiments, the checks may be conducted in other manners, and the user may be notified through other means. For example, a signal that is inaudible to humans could be passed from the local number to the destination number via the server, and if this succeeds the user is informed via an SMS message.
[0054] In this embodiment, the final screen FIG. 4 c also informs the user that the diversions will automatically be deactivated upon expiry of the access period. At the end of the expiry period, the access number assigned to the user to provide access to the server 104 is unassigned, and returned to the pool of numbers. This breaks the diversion linkage between the local number and the destination number. In embodiments, it is then up to the user to remove the diversion of their local number to the previously assigned access number. In other embodiments, additional screens in the interface 400 are implemented to assist the user in removing the diversion. In yet other embodiments, all diversions are automatically adjusted following expiry of the access period.
[0055] Reference throughout this specification to “one embodiment”, “some embodiments” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment”, some embodiments” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.
[0056] Similarly it should be appreciated that in descriptions of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single disclosed embodiment. Thus, the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of this invention.
[0057] Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.
[0058] Furthermore, some of the embodiments are described herein as a method or combination of elements of a method that can be implemented by a processor of a computer system or by other means of carrying out the function. Thus, a processor with the necessary instructions for carrying out such a method or element of a method forms a means for carrying out the method or element of a method. Furthermore, an element described herein of an apparatus embodiment is an example of a means for carrying out the function performed by the element for the purpose of carrying out the invention.
[0059] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.
[0060] As used herein, unless otherwise specified the use of the ordinal adjectives “first”, “second”, “third”, etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner.
[0061] In the claims below and the description herein, any one of the terms “comprising”, “comprised of”, or “which comprises” is an open term that means including at least the elements/features that follow, but not excluding others. Thus, the term “comprising”, when used in the claims, should not be interpreted as being limitative to the means or elements or steps listed thereafter. For example, the scope of the expression a device comprising A and B should not be limited to devices consisting only of elements A and B. Any one of the terms “including”, “which includes” or “that includes” as used herein is also an open term that also means including at least the elements/features that follow the term, but not excluding others. Thus, “including” is synonymous with and means the same as “comprising”.
[0062] Similarly, the term “coupled”, when used herein, should not be interpreted as being limitative to direct connections only. The terms “coupled” and “connected,” along with their derivatives, may be used. The scope of the expression a “device A coupled to a device B” should not be limited to devices or systems wherein an output of device A is directly connected to an input of device B. It means that there exists a path between an output of A and an input of B which may be a path including other devices or means. “Coupled” may mean that two or more elements are either in direct physical or electrical contact, or that two or more elements are not in direct contact with each other but yet still co-operate or interact with each other. | A system for forwarding a call intended for a local telephone number to an overseas telephone number, the system including: an interface for receiving user input, the input including at least the local telephone number; a server for selecting a first access number from a pool of available access numbers, the access numbers each providing access to the server; and a processor for redirecting the call intended for the local telephone number to the first access number; wherein the server is further arranged to reroute the call to the overseas telephone number; and a method of use therefor. | 7 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to stoves and has particular (though not sole) application to slow combustion stoves.
2. Description of the Prior Art
Slow combustion stoves usually consist of a substantially airtight container with a restricted air inlet, a combustion zone and an outlet, so that by controlling the amount of air admitted to the combustion zone, the rate of combustion and the efficiency of combustion can be controlled.
Existing slow combustion stoves have not proved to be entirely satisfactory, as the very slowness of combustion may not allow for complete combustion.
There is a need to provide a slow combustion stove which allows for controlled and efficient combustion of wood and other material.
It is an object of this invention to meet this need by providing an improved slow combustion stove which will allow for controlled and efficient combustion.
In one aspect, the invention provides a stove including: a casing surrounding a combustion zone; a door in one wall of the casing, an air inlet in an upper region of the casing; a deflector in conjuction with said air inlet to deflect air downwardly within said casing past a transparent portion in a front face of said casing and to an outlet from said casing.
BRIEF DESCRIPTION OF THE DRAWINGS
Other aspects of this invention which should be considered in all its novel aspects, will become apparent from the following description, which is given by way of example only, with reference to the accompanying drawings, in which:
FIG. 1 is a vertical a cross-sectional view of a preferred stove in accordance with the invention
FIG. 2 is a plan view taken along line A--A of FIG. 1 with the top removed to show the baffle arrangement;
FIG. 3 is a partial diagrammatic perspective view showing the by-pass damper and interlock mechanism in accordance with the invention
FIG. 4 is a partial diagrammatic side view of the interlock arrangement showing the interlock in an engaged position in solid lines and in a disengaged position in dotted lines; and
FIG. 5 is a diagrammatic cross-sectional view of the damper/control rod assembly.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A slow combustion stove has a casing 10 with side walls 12 a front wall 13 incorporating an openable door 32, a rear wall 14, a roof 15, and a base 16. In this embodiment the housing is formed of metal and is provided with legs 17.
Within the casing 10, a substantially horizontally partition 20 is provided. Conveniently, the partition 20 is attached to the rear wall 14 and to almost the full length of the side walls 12 to provide a ceiling within the casing leaving an aperture for the escape of combustion gases around the end of the partition 20. In addition, a series of substantially upright baffles 21 and 22 are provided between the partition 20 and the roof 15. Conveniently, these baffles 21 and 22 are spaced as shown in FIG. 1, and the upstream baffle 21 is apertured so that the flow path of combustion gases along the interface between partition 20 and the roof 15 is substantially increased and is made substantially turbulent for efficient mixing of gases of combustion with unburnt gases.
An outlet 24 is provided in the casing 10 and this is conveniently in the form of an outlet flue. As shown in FIG. 1, the partition 20 extends from the rear wall 14 towards the front wall 13 of the casing 10.
To assist in starting of the slow combustion stove, a by-pass aperture 25 is provided in the partition 20 adjacent the outlet 24. The by-pass aperture 25 is closeable by a by-pass damper 26 which is slidable to position over the by-pass aperture 25 to control a direct draft from a primary combustion zone 40 via the by-pass aperture 25 to the outlet 24. Conveniently, control of the by-pass damper 26 is achieved by a control rod 27 slidably mounted with respect to the casing 10. As shown in FIGS. 1, 3 and 4, this control rod 27 has a substantially upright portion connected to the by-pass damper 26 and a substantially horizontal portion passing through an aperture 28 in the outlet flue and supported by an apertured support 30 towards the front end of the casing 10. A handle 31 is provided on an outer end of the rod 27.
With specific reference to FIGS. 3 and 5, the by-pass damper 26 is preferably provided in a substantially heavy material for example cast iron and the like and is preferably provided as a substantially annular disc-like member having a substantially planar lower face 50 and a substantially circular periphery 51 however, in alternative forms of the invention, it is to be appreciated that the annular nature of the by-pass damper 26 is in no way essential.
The by-pass damper 26 is provided in this form of the invention with a substantially recessed upstanding part 52 substantially medially thereon, said upstand 52 incorporating an opening 53 therein, within which an end 54 of the upright portion of the control rod 27 engages. It is to be appreciated that the engagement of the end 54 of the control rod 27 with the by-pass damper 26 is in a substantially loose fit arrangement so as to allow a degree of float to occur between the end 54 and the by-pass damper 26 and further, to allow the by-pass damper 26 to be free to rotate relative to the end 54.
In view of the substantially heavy construction of the by-pass damper 26 it will be appreciated that the by-pass damper 26 is biased by gravity against the upper surface of the partition 20 upon which it slides and into a close association with said by-pass opening 25 when positioned thereover.
In alternative forms of the invention, it is envisaged that some biasing means could alternatively be provided for biasing the by-pass damper 26 downwardly over the by-pass aperture 25 such as for example spring means and the like. Owing to the substantially floating nature of the by-pass damper 26 relative to the control rod 27 it will be appreciated that expansion and contraction of adjacent parts of the structure in use can be accommodated by the by-pass to thus avoid the possibility of the by-pass damper 26 jamming or sticking in an undesired position, such as in the open position which could result in fierce primary combustion operation and therefore danger.
The biased, by-pass damper 26 further provides a substantially safety or pressure relief valve action to the stove whereby in the event that a sudden increase in pressure is encountered within the primary combustion zone 40, the pressure can overcome the downward bias of the by-pass damper 26 when closed over the by-pass aperture 25 to thus rapidly release the pressure from within the casing 10.
The casing 10 is provided with a transparent portion in the front face 13 thereof. Preferably the door 32 has a window, or the like so that the combustion zone 40 can be observed. The door 32 is hingeably mounted along one side edge and is positioned above a lower tray 34. The tray 34 can be provided with a sufficient lip to retain combustion residues such as ash, where the stove is intended as a wood burning stove. Suitably sealing flanges 33 are provided around the edge of the door 32 to provide a tight seal.
A controlled air inlet 35 is provided above the door 32, the control of the air inlet 35 is provided by a regulator in the form of a sliding baffle plate 36 (see FIG. 3) with an aperture in the front 13 of the casing 10 making up the air inlet 35. With reference to FIG. 1, a deflector 37 is provided within the casing in association with the air inlet 35, this deflector 37 takes the form of a plate or vane depending downwardly within the casing and having an outlet so arranged as to deflect inlet air downwardly over the inner face of the transparent portion thus in use reducing window temperature and assisting in avoiding soot, smoke and other residues of combustion building up on said window.
In this form of the invention, an interlock is provided between said door 32, said by-pass damper 26 and control arm assembly 27.
In this form of the invention, and with specific reference to FIGS. 3 and 4, an interlock as generally indicated by arrow 60 is provided as a substantially catch-like member 61 associated with the front face 13 of the casing 10 adjacent an opening edge 32A of the door 32. The interlock 60 includes a substantially U-shaped bracket 62 having legs 63 of the bracket 62 engaged with the front face 13 and slots 62a provided in each leg 63, to align with each other and substantially slidably mount an elongate finger 64 therein. The finger 64 has a butt end 65 thereof engaged with an outer portion 27a of the control arm 27; the butt end 65 is provided with a loose fit aperture therein, through which the outer portion 27a of the control arm 27 engages.
With particular reference to FIG. 4, the outer end 27a of the control arm 27 is provided with a cam portion 66 thereon being provided as the outer end portion 27 angled out of alignment with remaining portions of the control arm 27 so as to provide substantially ramped surfaces 67 which, upon longitudinal movement of the control arm 27 in directions of arrows 68, impinge on adjacent portions of the loose fit aperture. In this form of the invention, the outer end portion 27a of the control arm 27 is angled downwardly to provide the cam portion 66 and then outwardly toward the handle 31.
A distal end portion 69 of the finger 64 engages within a stop member 70 formed on an inner face of the door 32 so that when in an engaged position as shown in FIGS. 3 and 4 the distal end 69 engages behind an upstanding part 71 of the recess 70 to hold the door 32 in a closed position, yet upon movement of the control arm 27 by drawing the control arm 27 outwardly of the stove, it will be appreciated that the finger 64 rides up the cam portion 66 and is thus raised to disengage the distal end 69 from the stop member 70 and thus facilitate the opening of the door 32. Movement thus of the control arm 27 also removes the by-pass damper 26 from the by-pass aperture 25.
Returning again to FIGS. 1 and 2, main combustion zone 40 is provided in the lower region of the casing 10 and for purposes of illustration a log 41 is shown together with broken line X to indicate the general flow path of primary air and combustion gases during the main combustion mode. The path of secondary air entering through the inlet 35 is shown by broken line Y.
The stove may be surrounded by a heat exchanger housing, through which, air may be drawn by convection to provide a further heating effect so that air moving around the sides 12, 14 of the stove will be heated, and can then pass out of the housing to heat the room. Such a housing 44 is shown by broken lines to illustrate the type of housing suitable for a stove which may fit within an existing fireplace. The housing 44 being provided with an outlet grill 45, and an inlet 46.
In use, a fire can be started by using kindling around a log or other article to be burned, fully opening the air inlet 35 and moving and by-pass damper 26 to open the by-pass aperture 25. Once a fire has started, the by-pass damper 26 and air regulator 36 can be adjusted until the main combustion mode is achieved. This is shown in FIG. 1 where the by-pass damper 26 is fully closed. Primary air enters through controlled inlet 35 and is deflected downwardly over the transparent portion of the door 32 and onto the log in the primary combustion zone 40. Combustion gases follow a path approximately that of the broken line X sweeping over the log, around the underside of partition 20 and thence through the baffles 21 and 22 to the outlet 24. The path X is in effect a "rolling smoke action" and can be seen if smoke producing material is introduced into the combustion zone.
After primary combustion at 40, gases re-ignite in the secondary combustion zone both adjacent the underside and front of the partition and between the partition 20 and the roof 15. Secondary air from the inlet 35 follows path Y and combines with any unburned combustion gases to enable said secondary combustion.
The controlled amount and direction of air flow X in the main combustion zone means that a log situated within the main combustion zone 40 can be burned slowly (if the air inlet 35 is restricted). In fact, a log can be burned slowly from the door end towards the rear wall in the manner of a cigar, with the ash remaining in place. This rolling smoke action is believed to assist in the production of charcoal and in more efficient combustion of logs and the like.
It will be appreciated that by providing an interior partition 20 as illustrated in conjunction with a movable outlet baffle 26, it is possible to provide a slow combustion stove which is readily started and easily converted to the slow combustion mode. In addition, by providing a partition and a series of baffles between the partition 20 and the roof 15, it is possible to increase the flow path distance and increase turbulence of secondary combustion gases, and thus the heating of the stove as well as continuing the secondary combustion zone. By providing an air inlet above a transparent portion in the door 32 it is possible to use the inlet air to cool the interior face of the door, and also to assist in keeping it free of soot, ash, stains and the like. This upper air inlet also assists in providing the rolling smoke action.
Moreover, this upper air inlet does away with the need for a separate secondary air inlet and allows the primary air which sweeps down over the door to be pre-heated before reaching the combustion zone.
By providing a tray 34, it is possible to collect combustion residues in the bottom of the stove so that the stove does not need to be cleaned daily where wood is burnt. If coal of other fuel is to be used, then a grate should be used.
It is also believed that by providing an uncooled inner ceiling or partition 20, better combustion of the unburned gases is achieved and the possibility of soot formation is reduced.
Although only two sets of baffles are illustrated, it will be noted that other numbers of configurations of baffles could be utilized. It will be appreciated that the stove may be free standing, or mounted in a fireplace, or provided with a heat exchange housing for convection air if required.
Although the stove shown in the drawings is box shaped it will be appreciated that the casing can be any desired shape and need not be of rectangular configuration. Indeed, for styling purposes the exterior of the stove may be formed of a curved or rounded configuration.
Whilst the invention has been described with reference to a preferred embodiment, it will be appreciated that various other alterations or modifications may be used to the foregoing without departing from the scope of this invention, as exemplified by the following claims. The claims also form part of the description. | A slow combustion stove having a transparent portion to enable vision into a primary combustion zone so that flames are visible in use has a double burning combustion chamber defined by the primary combustion chamber and a partitioned off secondary burning combustion chamber, an air inlet to enable air to circulate within the stove adjacent a deflector which deflects the incoming air over the transparent portion to cool and resist staining and soot build-up thereon. A majority of the air passes to the primary combustion zone and a proportion of further gases enter the secondary combustion chamber with the gases of primary combustion for combustion of smoke and other unburned gases. A by-pass is provided for by-passing the normal combustion flow path when lighting the stove and additionally, an interlock is provided for preventing accidental opening of a door into the stove while the by-pass is closed, said by-pass damper is jamming resistant and acts as a pressure relief valve by virtue of the provision of a damper head to float and rotate relative to its mounting and support. | 5 |
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to a method of stitching component elements of road vehicle tires.
The present invention is particularly suitable for producing the second stage assemblies of radial tires, to which specific reference is made in the following description purely by way of example, and for assembling first stage to second stage assemblies.
2. Background Information
According to European Patent Application publication no. 0540048 filed by the present Applicant, a radial tire is produced by forming the second stage assembly of the tire on the inner surface of a toroidal body; separately forming the first stage assembly of the tire on inner rings supporting the bead portions of the first stage assembly; placing the first stage assembly inside the toroidal body and on the inner surface of the second stage assembly; forming the sidewalls of the tire, which are placed on the first stage assembly; and assembling annular walls for connecting the toroidal body and inner rings and so forming a mold suitable for use as a curing mold.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a straightforward, relatively low-cost stitching method for achieving substantially perfect adhesion of pairs of mutually contacting component elements of tires produced as described above.
According to the present invention, there is provided a method of stitching component elements of road vehicle tires. The method comprises stages consisting in placing a first component element inside a second component element housed inside a hollow body with adjustable supporting means; inserting stitching means inside the first component element and the hollow body; moving the stitching means into a raised position to engage the first element and compress the second element between the first element and the hollow body; adjusting said supporting means so that the hollow body weighs at least partly on the stitching means; and rolling the stitching means in contact with the first element.
Preferably, in the above method, said supporting means comprise a roller saddle of adjustable width; and said hollow body comprises a toroidal body mounted on the roller saddle so as to rotate about a substantially horizontal axis. The toroidal body is caused to weigh at least partly on the stitching means by increasing the width of the saddle.
BRIEF DESCRIPTION OF THE DRAWINGS
A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:
FIG. 1 shows an axial section of a stitching unit implementing the method according to the present invention;
FIG. 2 shows a section along line II--II in FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Number 1 in FIG. 1 indicates a stitching station for a radial tire (not shown), defined by a device 2 for forming and transferring a second stage assembly, i.e. tread assembly, 3; and by a stitching device 4 for ensuring the mutual cohesion of two annular component elements 5 of assembly 3, consisting respectively of a tread 5a and a tread belt 5b.
Device 2 comprises a carriage 6; and a toroidal body 7 supported on carriage 6 with its axis 8 arranged substantially horizontally, and in turn comprising an intermediate annular body 9 for housing assembly 3. Annular body 9 is externally cylindrical, and is defined internally by an annular surface 10 having a curved inwardly-concave section and designed to contact the outer surface of assembly 3. Toroidal body 7 also comprises two outer annular flanges 11 extending radially outwards from the opposite axial ends of annular body 9.
In addition to carriage 6 and toroidal body 7, device 2 also comprises a fixed frame 12, and two parallel rails 13 supported in a fixed position on frame 12, and in turn supporting carriage 6 in a sliding manner.
As shown more clearly in FIG. 2, carriage 6 comprises a base 14, in turn comprising two parallel cross members 15 perpendicular to rails 13, each presenting two end shoes 16 fitted in a sliding manner to rails 13, and a horizontal platform 17 between shoes 16 and facing the other cross member 15. Base 14 also comprises two lock devices 18 for fixing base 14 to rails 13 in any given position; and a horizontal plate 19 having opposite peripheral portions resting on and connected integral with platforms 17, and which presents a central hole 20 with a vertical axis 21, and an upper annular rib 22 extending about hole 20 and coaxial with axis 21. Upwards from plate 19, there extends a tubular body 23 connected integral with plate 19, coaxial with axis 21 and hole 20, and which is engaged, together with hole 20 and via the interposition of radial bearings 24, by a pin 25 extending downwards from a substantially rectangular platform 26 connected for rotation to the top free end of body 23 via the interposition of a thrust bearing 27. From the bottom surface of platform 26, there extend downwards four brackets 28 equally spaced about axis 21, each supporting a roller 29 running along an annular track coaxial with axis 21 and defined by the annular top end surface of rib 22.
The top surface of platform 26 is fitted integral with two substantially horizontal rails 30 symmetrical in relation to axis 21 and supporting in a sliding manner a saddle 31, in turn supporting toroidal body 7. Saddle 31 comprises two parallel cross members 32 perpendicular to rails 30, each presenting two end shoes 33 connected in a sliding manner to rails 30, and a horizontal platform 34 between shoes 33. The top surface of each platform 34 is fitted integral with a roller support 35 comprising two supports 36 aligned along a respective axis 37 parallel to respective cross member 32. Via the interposition of respective bearings, supports 36 support for rotation a shaft 38, the opposite ends of which project outwards of supports 36 and are fitted with respective rollers 39, each coaxial with respective axis 37 and having a groove 40. One of shafts 38 may be connected to the output of a motor 41 supported on a respective shoe 33. As shown in FIG. 1, the length of shaft 38 is such that the distance between grooves 40 on rollers 39 of each roller support 35, equals that between the two flanges 11.
As shown in FIG. 2, cross members 32 are fitted through with respective nut screws 42 coaxial with each other along an axis 43 extending transversely to axes 37, and are engaged by respective oppositely threaded screws 44 connected at one end by a central block 45. Nut screws 42 and screws 44 constitute a device 46 for adjusting the width of saddle 31 within a given range, and which presents an external control handle 47 fitted to one of the screws 44, and a releasable lock device 48 for preventing rotation of screws 44.
As shown in FIG. 2, toroidal body 7 is placed on saddle 31 with each flange 11 engaged inside the grooves 40 of two rollers 39, so that it can be moved along its own axis 8 by moving carriage 6 along rails 13; rotated about axis 8 by means of motor 41; adjusted manually about axis 21 (or by means of a known motor, not shown, connected to pin 25); and moved, by means of device 46, transversely in relation to axis 8 and in the direction of axis 21.
Stitching device 4 comprises an upright 49 fitted at the bottom end to frame 12, between rails 13, and fitted at the top end with a plate 50 supporting a geared motor 51, with an output screw 52 extending parallel to upright 49 and between plate 50 and a lateral bracket 53 on upright 49. Screw 52 is fitted with a nut screw 54, the lateral surface of which is fitted integral with a slide 55 connected in a sliding manner to a guide 56 parallel to and integral with upright 49, so that, when geared motor 51 is operated, nut screw 54 travels, without rotating, along upright 49. On the opposite side to slide 55, nut screw 54 is fitted with a shaft 57, in turn fitted in an idle manner with a stitching drum 58 having an axis of rotation 59 parallel to axis 8. Alternatively, shaft 57 is tubular and houses a motor (not shown), the output shaft (not shown) of which is fitted with drum 58.
In actual use, following insertion of tread belt 5b inside tread 5a contacting surface 10 of toroidal body 7, carriage 6 is moved along rails 13 so as to insert drum 58, initially positioned with axis 59 coaxial with axis 8, inside toroidal body 7.
Motor 51 is then operated to raise drum 58, so as to bring its outer surface into contact with the inner surface of tread belt 5b, and compress tread 5a between tread belt 5b and surface 10. At this point, adjusting device 46 is activated by means of handle 47 to slightly widen saddle 31, so that toroidal body 7 weighs partly on drum 58, thus increasing by the force of gravity the contact pressure between elements 5, but without detaching toroidal body 7 from rollers 39 which are rotated by motor 41 so as to rotate toroidal body 7 in relation to drum 58, and so stitch tread belt 5b on to tread 5a.
Station 1, which in the non-limiting example shown provides for internally stitching second stage assembly 3, may of course be used in exactly the same way as described above for internally stitching assembly 3 to a first stage assembly, i.e. carcass, not shown.
From the foregoing description and the operational discussion, when read in light of the several drawings, it is believed that those familiar with the art will readily recognize and appreciate the novel concepts and features of the present invention. Obviously, while the invention has been described in relation to only a limited number of embodiments, numerous variations, changes, substitutions and equivalents will present themselves to persons skilled in the art and may be made without necessarily departing from the scope and principles of this invention. As a result, the embodiments described herein are subject to various modifications, changes and the like without departing from the spirit and scope of the invention with the latter being determined solely by reference to the claims appended hereto. | A method of stitching component elements (5) of a radial tire, whereby an inner component element (5b) is placed inside an outer component element (5a) housed inside a toroidal body (7) mounted for rotation about a horizontal axis (8) on a saddle (31) adjustable in width and supported on a carriage (6). A stitching drum (58) is inserted inside the inner component element (5b) and toroidal body (7), and is moved radially upwards to compress the outer component element (5a) between the toroidal body (7) and the inner component element (5b). The saddle (31) is widened so that the toroidal body (7) weighs on the stitching drum (58), and the toroidal body (7) and stitching drum (58) are rotated in relation to each other. | 1 |
BACKGROUND OF INVENTION
[0001] The present invention relates to a multi-function, multi-mode marker/signaling device in the visible and/or infrared spectrum with steady, flash and/or coded flash signals for marking or identification purposes in low/no light conditions.
[0002] The device is multi-modal, and multi-functional with single or dual user-selectable operating modes, with two or more distinct operating functions within each operating mode. Visible and invisible (infrared) marking is provided by multi-colored light emitting diodes (LED) or infrared (IR) emitters (emitters). Each distinct function can be varied with respect to output in the visible spectrum (visible) or infrared (IR), with respect to combinations of visible and/or IR emissions, and with respect to variable intensities, and can be positioned in either a steady ON or flash-coded mode for marking or identification in the low/no light conditions. It is designed for detachably mounting onto the top, back, front, or sides of helmets as a signal marking identification, position, or location, and for collision avoidance by parachutists during night jumps in free fall or under canopy. It can also be adapted to mount on other gear, vehicles or structures as the military missions or other uses dictate.
[0003] It is an object of the invention to provide both a visual and tactile (touch) means of determining and verifying ON/OFF, and operating mode, and functional operating status of the device that is positive, unambiguous and constantly available, without having to rely on passive, transitory vibratory feedback that can be masked in a high noise, high vibration environment or confused or forgotten. The positive and constantly available visual and tactile (touch) verification means also helps to preclude battery depletion if the device were to be inadvertently left ON in an invisible, infrared (IR) operating mode.
[0004] It is an another object of the invention to provide low profile housing with a curved, minimally obstructive shape on all sides and edges to mount on helmets or other equipment or structures, and particularly to provide minimal snag potential or interference with objects that may be encountered including parachute lines and risers during parachute operations.
[0005] It is another object of the invention to provide a device that offers a low force, passive emergency breakaway, detachability feature to prevent head or neck injury to the wearer in the event that the device should interfere with parachute lines or risers during deployment of the parachute or interference with other obstacles.
[0006] It is another object of the invention to provide a low profile and shaped design on all sides and edges with no substantial protuberances violating the curvilinear dome-like external shape of the device in order to provide a low wind resistance shape which does not create wind-rush noise or significant additional wind loads on the head and neck of a parachutist during the high speed free fall segment of some parachute missions.
[0007] It is another object of the invention is to provide combinations of two, three, four or more different user-defined and selectable functions within one or two user-defined, selectable, and independent operating modes and in a single device allowing users to acquire only one specific device to be used for multiple and distinct mission requirements such as tactical and training operations.
[0008] It is another object of the invention to provide the ability to select between two distinct and independent operating modes with two or more discreet functions within each operating mode, and to effectively separate and segregate these independent sets of functions by mechanical switching means whose relative position and therefore, operating status, are confirmable by two positive, unambiguous, and constantly available methods, e.g, visual and tactile (touch), to facilitate use of the same device in different mission environments such as training (e.g., non-secure visible emissions) and tactical (e.g., secure, infrared/IR emissions). This feature is novel in comparison to other lighting devices purpose-built for helmet mounting including those with rotating ring switches, opposed simultaneously activated pressure switches, and push-button ON/OFF switches where there may be no positive, unambiguous and constantly available visual and tactile (touch) means of confirming operating status.
[0009] It is another object of the invention to provide a variety of emitters to allow a user-defined selection of different signaling outputs in the visible and/or infrared spectrum.
[0010] It is another object of the invention to provide two mechanically similar, interactive, but independent emitter activation switch means which comprise mechanically sliding switch(es) and/or repositionable magnetic/reed switch/plug arrangements for function and/or operating mode selection. This feature is novel in comparison to other lighting devices purpose-built for helmet mounting that may use in combination two or more dissimilar and potentially confusing switching means.
[0011] It is another object of this invention to provide a function-selection switch means which allows for the selection of two or more functions within one or two user-defined and selectable operating modes.
[0012] It is another object of the invention to provide a mode-selection switch means to allow a user, in the field, to have the ability to change to or select from one set of two or more functions to another set of two or more functions, in the same device, without tools or programming, and to make such switching means independent of one another to the extent that one or the other mode of operation (such as overt/visible versus covert/infrared may be selected without dependence upon first being in one or the other mode.
[0013] It is another object of the invention to provide one or more switching means which can be activated single-handedly, in total darkness and/or outside of direct visual contact, with a single digit (thumb or finger) precluding the necessity for the simultaneous use of multiple digits (e.g, thumb and finger) to turn a rotating ring or simultaneously press multiple switches to invoke any operating function.
[0014] It is another object of this invention to provide a dual purpose switch means retainer providing the ability to accommodate either (a) a sliding magnetic/reed switch arrangement which allows for the two sets of functions to be switchable by the user at will, or (b) a more secure repositionable, snap-in magnet switch/plug which requires pre-selection of a specific set of functions thereby helping to prevent inadvertent activation of an undesirable set of functions under a given mission environment.
[0015] It is another object of the invention to provide a battery compartment with access arrayed on the bottom or mounting interface surface of the device by which access to battery is protected and secured in the interface between the invention and the helmet or structure to which is it mounted and which is separately sealed with a flexible sealing plug.
[0016] It is another feature of the invention, by virtue of its unique battery containment and access arrangement to locate battery electrical contacts, access means, and switch means in such a way as to (a) preclude snag-prone protuberances which otherwise might violate the curvilinear, dome-like shape of the exposed surfaces of the device and thus further reduce potential interference (snagging) on external objects which could cause injury to the user/wearer, and (b) provide an uninterrupted curvilinear, dome-like surface through which emitted light may be radiate in substantially all directions.
[0017] It is another object of the invention to provide the ability to activate, de-activate, change functions, and/or radiate user-defined emissions based on built-in sensing capabilities to include (a) barometric pressure sensors (e.g., altitude), and (b) accelerometers (e.g, motion or tilt angle).
[0018] It is another object of the invention to provide the ability to sense illumination and interrogation by remote RF or IR sources such as Identification Friend or Foe (IFF) devices, and to provide a pre-set, programmable coded response via its various emitters which will identify the wearer of the invention as a friendly force and thus avoid “friendly fire” casualty.
SUMMARY OF THE INVENTION
[0019] The general purpose of the present invention, which will be described subsequently in greater detail, is to provide a multi-mode, multi-function marker/signaling device for steady and flash-coded identification in the visible and/or infrared spectrum for any marking or identification purpose in low/no light conditions.
[0020] To attain this, the present invention comprises a cover having a first (main) switch means and second (nose) switch means cavity at opposing ends. A clear or translucent lens is integrally formed as a part of the cover. A base is secured to the cover by attachment means such as screws, ultrasonic welding, or sealing adhesives. An O-ring or other seal provides waterproofing and dustproofing for the space housing the electronics and captured between the cover and the base.
[0021] A electronic circuit board having a first switch board and a second switch board is mounted within the waterproof space defined by the cover and base. There is a first switch means mounted within the first (main) switch means cavity of the cover and a second switch means mounted within the second (nose) switch means cavity of the cover. The switch means are in electronic communication with the electronic circuit board.
[0022] A main electronic circuit board having a first switch circuit, and a second switch circuit board mounted within the waterproof space defined by the cover and base. There is a first switch means mounted within the first (main) switching means cavity of the cover and a second (nose) switch means mounted within the second (nose) switching means cavity of the cover. The two switch means are in electronic communication with the electronic circuit board via magnetic field effects on electronic reed switches.
[0023] A variety of light emitting diodes (LEDs) and/or infrared (IR) emitters are mounted on the electronic circuit board. The LEDs and emitters can be multi-colored, white, or infrared (IR). The switch means are capable of being set to different positions to interact with the programmable circuitry on the electronic circuit board in order to actuate a different combination of visible or infrared (IR) emissions, depending on the pre-programmed settings.
[0024] A primary (non-rechargeable) or secondary (rechargeable) battery provides the power source. A battery containment compartment comprises an integral part of the base with access to that compartment arrayed on the outside/bottom surface of the base which forms the surface by which the device is mounted to other equipment or structures. A battery sealing plug secures and protects the battery within the containment compartment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] 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 thereof. Such description makes reference to the annexed drawings wherein:
[0026] FIG. 1 a is a front perspective view of the present invention and FIG. 1 b is a rear perspective view of the present invention.
[0027] FIG. 2 a is a side elevational view, FIG. 2 b is a top plan view, FIG. 2 c is a bottom plan view, FIG. 2 d is a rear elevational view and FIG. 2 e is a front elevational view of the present invention.
[0028] FIG. 3 a is a front perspective view of an alternate embodiment of the present invention and FIG. 3 b is a rear perspective view of an alternate embodiment of the present invention.
[0029] FIG. 4 a is a side elevational view, FIG. 4 b is a top plan view, FIG. 4 c is a bottom plan view, FIG. 4 d is a rear elevational view and FIG. 4 e is a front elevational view of an alternate embodiment of the present invention.
[0030] FIG. 5 is an exploded view of the present invention.
[0031] FIG. 6 is an exploded view of an alternate embodiment of the present invention.
[0032] FIG. 7 a is a view of the device in use attached to the back of a helmet, and FIG. 7 b is a view of the device in use attached to the top of a helmet.
DETAILED DESCRIPTION OF THE INVENTION
[0033] Referring to the drawings FIGS. 1 to 7 , generally, the present invention 10 will now be described in greater detail. A cover 12 is comprised of an outer surface portion 14 and a clear, tinted and/or translucent lens 16 . The outer surface portion 14 has a first (main) switch means cavity 18 defined at a first end and a second (nose) switch means cavity 20 defined at an opposed second end. The cover 12 is generally dome-shaped in all cross sections and is of compact size. The conforming shape on all sides provides for minimal snag hazard to avoid personal injury during parachute operations and to provide an aerodynamic, low noise, low drag shape for the high speed free fall portion of some parachute operations. The outer surface portion 14 has bores 22 that are inwardly threaded juxtaposed the first (main) switch means cavity 18 and the second (nose) switch means cavity 20 , respectively, and further has bores 22 extending through a bottom surface of the outer surface portion 14 . An indentation with numerical indicia 24 affixed is defined at the first end of the cover 12 . It is understood that the relative orientation of the first switch means and the second switch means may be perpendicular, as shown in the figures, or parallel.
[0034] A base 28 is comprised of an upper surface 30 , a lower surface 32 with a passage defined therethrough, a perimeter edge 34 and having bores 22 that are inwardly threaded defined through the upper surface 30 and the lower surface 32 . The base 28 is preferably arcuate in shape to conform to the configuration of headgear, such as a parachute helmet. However, the lower surface 28 may be flattened to mount on other surfaces. Fastening means 36 , such as hook and loop material (Velcro®), is present on the lower surface 32 to secure the invention 10 to a helmet and the like. FIGS. 7 a and 7 b illustrate the invention 10 mounted on a helmet in two of several possible locations.
[0035] A seal 32 , preferably formed of a flexible rubber or rubber-like material to provide hermetic sealing, is mounted to and extends around the top perimeter sealing and interface edge 34 . The cover 12 is mounted on the base 28 and secured with attachment screws 26 extending through bores 22 in the outer surface portion 14 and the base 28 , and further defining an open cavity.
[0036] A battery containment compartment 40 having an outer surface and an inner surface with an open cavity defined by the inner surface is integrally formed on the upper surface 30 of the base 28 . The compartment 40 is of predetermined size to accept rechargeable or non-rechargeable batteries. Battery contacts 42 are affixed on the inner surface of the battery containment compartment 40 and in electrical communication with the electronic circuit board 52 through slots 86 at each end of the battery containment compartment. A battery 44 is a power source for the invention 10 and is encased within the battery containment compartment 40 . Slots 86 translating between the inner and outer surface of the battery containment compartment 40 are provided for the installation of the battery contacts 42 . The slots 86 are filled and covered with sealant to provide waterproof and dustproof sealing of the battery contacts 42 as installed in the slots 86 .
[0037] Battery replacement is accomplished by opening a battery sealing plug 46 mounted to the lower surface 32 of the base 28 via attachment screws 26 with washers 50 . The plug 46 is preferably molded of a flexible rubber or rubber-like material and has a flexible sealing surface 48 formed to sealably engage with the periphery of the outer edge of the battery containment compartment 40 . The battery sealing plug 46 has a recess 88 formed therein to interface with the shape of the battery 44 to assist in retention and sealing. By placing battery replacement through the passage of the base 28 , the battery 44 is secured within the mounting interface between the invention 10 and the structure, such as a helmet, upon which the invention 10 is mounted. This method of battery installation and replacement is novel in comparison to other helmet mounted devices. The sealing plug 46 provides hermetic sealing against air, moisture, and dust.
[0038] An electronic circuit board 52 comprising electronic components, sensors/receptors, circuits, a processor and a memory coupled to the processor is disposed on the upper surface 30 of the base 28 and positioned within and captured by the surfaces defining the open cavity of the cover 12 and the base 28 . The electronic circuit board 52 is electronically coupled with the battery 44 . The electronic circuit board 52 has a first (main) switch means circuit board portion 54 attached thereto and a second (nose) switch board portion 56 . The electronic circuit board 52 provides multi-function, multi-color/radiation multi-mode features, and includes a built-in programmable integrated circuit (PIC). Steady illuminated and various flashing functions can be programmed with variable oscillation patterns, variable intensity, and variable sequencing to provide appropriate intensity/visual acuity and/or coded or information-contained pulses.
[0039] A sliding main switch 60 coupled with a small disc magnet 62 is mounted within a main switch retainer 64 defining a series of two or three split capture rings 84 . The main switch 60 interacts with electronic reed switches (not shown) disposed within the cover 12 , upon the main switch board 54 . Electronic reed switches are well known and not described here. The sliding main switch 60 is in electronic communication with the main switch board 54 . A mechanical detent is defined for each position of the sliding main switch 60 by the split capture rings 84 . Thus an appropriate level of hoop stress is allowed to solidly capture the sliding main switch 60 in each split capture ring 84 and to provide an appropriate level of resistance when moving from one split capture ring 84 position to the other. The main switch retainer 64 is secured juxtaposed the first (main) switch means cavity 18 with attachment screws 26 . The numerical indicia 24 affixed on the outer surface portion 14 are labeled “0,” “1,” and “2”. The sliding main switch can be positioned in OFF (Function“0”) and two selectable operating modes, labeled “1” and “2.” The sliding main switch 60 can thus be ergonomically actuated by the user's thumb, in low/no light intensity situations, and in the same manner the ON/OFF status of the device and/or its precise operating function can be determined by tactile feel while the invention 10 is mounted on a helmet (as shown in FIGS. 7 a and 7 b ).
[0040] A sliding nose switch 66 coupled with a build-in disc magnet 68 is mounted within a nose switch retainer 70 . The retainer 70 is secured within the second (nose) switch means cavity 20 of the outer surface portion 14 with attachment screws 26 . The magnet 68 interacts or fails to interact with an electronic reed switch (not shown) disposed within the cover 12 upon the electronic circuit board 52 . The sliding nose switch 66 is in electronic communication with the nose switch circuit disposed on the circuit board 56 . The sliding nose switch 66 provides the user the ability to select a unique third function (“Function 3 ”) or one of two distinct operating modes: Mode A (such as overt or visible) or Mode B (such as covert or infrared), depending on the particular embodiment of the invention.
[0041] Alternatively, a nose switch/plug 72 replaces the sliding nose switch 66 . The nose switch/plug 72 has an upper surface 78 , a lower surface 80 to which are attached two downwardly depending flanged structures 82 which engage with split capture rings 84 of the nose switch retainer 70 . The nose switch/plug 72 is reversible and repositionable, and mounts in and is secured by the nose switch retainer 70 . The nose switch/plug 72 is coupled with an asymmetrically located magnet 74 located in one of the flanged structures 82 which interacts (or fails to interact) with an electric reed switch disposed upon the electronic circuit board within the cover 12 . The interaction of the magnet 74 and reed switch provides for selection of a third function or alternate modes of operation depending on the particular embodiment of the invention. The nose switch/plug 72 has directional indicator indicia 76 shaped generally like an arrow affixed to the upper surface 78 to allow the user to orient the nose switch/plug 72 either UP or DOWN to provide visual and/or tactile cue as to a particular operating mode. The nose switch/plug 72 functions as a mode-of-operation selector. The user in the field has the ability to change from one set of two functions to another unique set of two functions without tools or programming by repositioning the nose switch/plug 72 .
[0042] A plurality of emission sources 58 comprised of a variety of types and colors of LED and infrared emitters are disposed on the electronic circuit board 52 and are in electrical communication with the electronic circuit board 52 . The features can be combined and/or manipulated in ways to provide two, three, four or more different user-defined and selectable functions. Multiple Red/Blue/Green (RGB) three-chip LEDs provide the ability to emit primary colors as well as a range of other colors as variations in a single light source 58 . Multiple high-intensity “white” light LEDs are provided to meet FAA parachuting requirements at night and to provide for special mission requirements including emergency signaling (“strobe” effects). Multiple infrared (IR) emitters and/or LEDs are provided for covert operations.
[0043] Any of the emitter sources 58 can be operated at the same time individually or in tandem with other emitter sources, each in either flashing or steady ON. For example, in one operating mode four RGB light sources 58 are operating in constant Green/Steady while two high intensity white light sources 58 are operating intermittently in a flashing mode. Furthermore the electronic circuit board 52 can be programmed to allow the emitter sources 58 mounted at one end of the electronic circuit board 52 to be set in different color/intermittent/steady modes from the light sources 58 at the opposed end of the electronic circuit board 52 .
[0044] The multi-function, multi-color/radiation, multi-mode features of the invention 10 are facilitated by a programmable integrated circuit (PIC). The steady ON and flashing functions can be programmed with variable oscillation patterns and peaks and sequencing to provide increased intensity/visual acuity and/or coded or information-containing pulses. The battery 44 outputs to the emitter sources 58 are controlled by the electronic circuit board 52 having programmable integrated circuits. Voltage regulator devices and/or circuits are added to the electronic circuit board 52 to match emitter input requirements and/or to achieve optimized output for specific mission requirements.
[0045] There are four general model configurations of the device. In the first two configurations the nose switch/plug 72 and the sliding main switch 60 are in use. In the first configuration the nose switch/plug 72 is fixed in one position with the integral direction indicator 76 oriented up and the sliding main switch 60 can be set to OFF (position “0”) or ON (position “1” or “2”). Thus, two functions are available. In the second configuration, four functions are available. The nose switch/plug 72 can be selected in either Mode A (direction indicator 76 up) or Mode B (direction indicator 76 down). The mode of the nose switch/plug 72 is changed by the user removing the nose switch/plug 72 , rotating the nose switch/plug 180° and reinstalling. The directional indicator 76 marks Mode A or Mode B selection by either an up or down direction. The main switch 60 is either set at OFF or ON position. The physical separation between the operating modes created by the two different installation positions of the nose switch/plug 72 prevents the possibility of inadvertent visual emissions in a mode of operation that has not be pre-selected by the nose switch/plug 72 .
[0046] The third general configuration incorporates the sliding main switch 60 and the sliding nose switch 66 . There are three variable, user-defined functions within one mode of operation. The sliding main switch 60 is either in the OFF position (“0”), or ON (position“1” or “2”). The sliding nose switch 66 provides a third operating function by being moved from its OFF (down) position to its ON (up) position. The movement of the sliding nose switch 66 to its ON position can be programmed to override the functionality of the sliding main switch 60 completely, no matter what position the sliding main switch 60 is in. In such case, movement of the sliding nose switch 66 back to its OFF position returns the functionality of the sliding main switch 60 to the operating function defined by its current position, and electronically locks-out and prevents the reactivation of the ON function of the sliding nose switch 66 until both the sliding main switch 60 and the sliding nose switch 66 are resent to their respective OFF positions.
[0047] The fourth general configuration incorporates the sliding main switch 60 and the sliding nose switch 66 and provides a minimum of four functions total. There are a total of two modes of operation (Mode A and Mode B), with a minimum of two functions in each mode. The sliding main switch 60 is either in the OFF (“0”) or ON (“1” or “2”) position. The sliding nose switch 66 can be either in Mode A or Mode B. Furthermore, the electronic circuit board of the device has the ability to re-program the function or mode of operation by cycling the main switch through a pre-established pattern of movements among main switch positions “0,” “1,” or “2.” The integral programmable integrated circuit (PIC) would detect these switch movements as powering ON and OFF through a preprogrammed code which, when detected by the PIC, would initiate a routine which would result in a change to a function or an operating mode. Not only would the user of the device have the ability to reprogram while in the field, but would also have a secure coded barrier between visible and covert operating modes.
[0048] The device 10 has vibratory means (e.g, a small electric motor with an eccentric rotating mass) in electrical communication with the electronic circuit board 52 , known to those skilled in the art, which provides vibratory feedback as a check of the status of the battery 44 . This battery status check and corresponding vibratory feedback from the device to the user/wearer every time the device 10 is activated and/or moved from one function to another, or whenever the battery contact is broken and re-made as when a battery is first installed, or temporarily removed and re-installed specifically to conduct a battery status check. Activation of the device or the change from one function to another or whenever fresh battery contact is made by installing a battery would actuate a programmed routine through a circuit separate from the lighting circuit whereby a voltage test of the battery under load is conducted against an on-board electronic reference such as a Zener diode. If the battery is at a voltage level associated with an acceptable level of remaining capacity, a predetermined vibratory pattern (e.g. three buzzes) would occur. If a depleted level of battery voltage (i.e, capacity) is detected, then a different pattern of vibratory signals (e.g., two buzzes) would be sent to show a lower state of battery readiness. At some predetermined battery voltage (capacity) level, the vibratory feedback (e.g., one or no buzzes) would alert the user that the battery 44 must be replaced.
[0049] The electronic components disposed within the cover 12 and base 34 and upon the electronic circuit board 52 and the nose switch board 54 are protected by the ring seal 38 or other sealing method such as ultrasonic welding to prevent moisture and dust intrusion. If attachment is made by mechanical means such as screws 26 , they would be installed with either O-rings or other compounds with sealant qualities.
[0050] 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, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims attached.
[0051] 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 only and should not be regarded as limiting the scope and intent of the invention. | A multi-mode, multi-function marker/signaling device, capable of detachably mounting to helmets, has operating switches with positive visual and tactile cues located at opposing ends. A cover is attached to a base to provide a waterproof internal space. An electronic circuit board mounted within the waterproof space includes one or more visible and/or infrared emitters. Built-in programming provides user-defined and selectable modes of operation and multiple functions within those modes by means of serial manipulation of each switching means with a single digit. The emitters are multi-colored and/or infrared devices operating either steady ON, flashing, or coded flash, and are programmed to operate either independently or together. A replaceable battery provides power. A battery compartment is integral to and accessed from the underside (mounting surface) of the base. | 0 |
BACKGROUND AND SUMMARY OF THE INVENTION
This application claims the priority of German application 198 50 257.5, filed in Germany on Oct. 31, 1998, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a disk brake protector for a disk brake, with a friction ring, of a motor vehicle with a perforated rim dish, said dish being mounted directly or indirectly on the steering knuckle or axle housing and covering at least a portion of the disk brake.
In heavy vehicles used on construction sites that carry loose material, for example, only drum brakes have been used on the rear axles. An important reason for this is the problem, unsatisfactorily solved so far, of encapsulating the disk brakes against loose material entering the wheel rim from the front in side dumpers.
A partially covered disk brake is known from German Patent Document No. DE 43 44 051 A1 in which a disk-shaped protective covering is fastened to a non-rotating axle part. The protective covering however is mounted on the side of the wheel that faces the interior of the vehicle, so that it cannot keep loose material entering the wheel or rim dish from the outside of the vehicle out of the brake system. It also has ventilation slots which cannot keep out loose material containing sand, for example.
The present invention addresses the problem of providing a protector for disk brakes that protects a disk brake system, located at least partially in the interior of the rim, from contamination and/or damage caused by dirt entering the interior of the wheel rim from outside.
The problem is solved by preferred embodiments of the present invention by providing a disk brake protector for a disk brake of a motor vehicle wheel having a friction ring, a perforated rim dish, fastened directly or indirectly to a steering knuckle or axle housing and covering at least a part of the disk brake, wherein the disk brake protector is located at least partially in a space between the disk brake and the wheel rim, said protector covering at least a portion of a surface on an outside of the wheel and a radial circumferential surface adjacent the friction ring of the disk brake.
The disk brake protector is located in the space between the disk brake and the wheel rim, covering at least a portion of the friction ring facing the outside of the wheel and the radial circumferential surface.
In certain preferred embodiments of the invention, the disk brake protector is a sleeve-shaped capsule provided at a short distance along the inside contour of the wheel rim. The capsule is fastened to the steering knuckle directly or on one or more non-rotating parts of a disk brake. Between the rotating wheel rim and the fixed capsule there is an annular gap with an approximately constant thickness. Loose material entering this annular gap thus cannot jam between the disk brake and the wheel rim.
The disk brake protector also prevents loose material, wet sand for example, from coming into direct contact with the friction ring of the disk brake. This is an important advantage because, although the sand does not cause jamming, when the vehicle is at rest it accelerates rust formation on the friction ring. In addition, at the first brake application after contamination, the sand adhering to the friction ring is forced into the rubbing surface of the brake pad. In the course of several subsequent brake applications, the sand grains that have been pushed in grind away the friction disk at a rate above average, causing increased wear.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWING
The single drawing FIGURE is a partial sectional view through a wheel with a disk brake and a disk brake protector, constructed according to a preferred embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The wheel, which is not driven in the embodiment shown, is mounted by two tapered roller bearings ( 3 ) on an stub axle ( 2 ) formed on the steering knuckle ( 1 ). The tapered roller bearings ( 3 ) support a wheel hub ( 4 ) which has a wheel hub flange ( 5 ) facing the outside of the wheel. An internally ventilated brake disk ( 20 ) is fastened to the inside of wheel hub flange ( 5 ) while a wheel rim ( 10 ) is bolted by wheel bolts ( 6 ) to the outside. Wheel rim ( 10 ) consists of rim ( 11 ) and a rim dish ( 12 ) welded to it. The rim dish ( 12 ), in the vicinity of weld ( 13 ) located between the wheel dish and rim ( 11 ), has a plurality of rim openings ( 16 ) distributed on the circumference. The openings have a round or oval contour, for example.
The disk brake is shown in the embodiment as a floating caliper brake. The floating caliper brake has a floating caliper ( 32 ) which is mounted displaceably in a stator ( 31 ) normal to friction ring ( 21 ) of brake disk ( 20 ). Stator ( 31 ) is rigidly fastened to wheel carrier ( 1 ). The fastening is not shown in FIG. 1 . The brake pads ( 34 ), located opposite the side surfaces of friction ring ( 21 ) can be seen inside floating saddle or caliper ( 32 ).
Brake pads ( 34 ) are fastened to plates ( 35 ) by which they abut floating caliper ( 32 ) and the brake piston(s), not shown. Plates ( 35 ) abut hold-downs ( 48 ) in the radial direction.
A disk brake protector ( 40 ) is located in the interior ( 17 ) of the rim. Disk brake protector ( 40 ) has a sleeve-shaped contour. It is located in the radial direction between friction ring ( 21 ) and rim ( 11 ). In the axial direction it is located mainly between friction ring ( 21 ) and wheel dish ( 12 ). With wheel bearings with an external wheel hub flange ( 5 ), as shown the disk brake protector ( 40 ) also lies partly between friction ring ( 21 ) and wheel hub flange ( 5 ).
The disk brake protector ( 40 ) shown in the embodiment is divided into four parts ( 41 - 44 ). The first part ( 41 ) forms the bottom of the sleeve with one central recess ( 46 ) for example. The latter for example is a circular hole whose diameter is a few mm larger than the diameter of the wheel hub at that point. The gap between wheel hub ( 4 ) and first part ( 41 ) allows air exchange between rim interior 17 and interior ( 51 ) of disk brake protector ( 40 ). As a rule, while driving, the air pressure in the interior of the rim is lower than in the interior ( 51 ) of disk brake protector ( 40 ), so that heat can be removed through rim openings ( 16 ) and an annular gap ( 53 ) between disk brake protector ( 40 ) and rim ( 11 ).
The second part ( 42 ) of disk brake protector ( 40 ) has a frustroconical contour. The angle of taper is preferably between 60 and 80 degrees for example.
The following, third part ( 43 ) is made cylindrical or at least approximately cylindrical. With the latter design, its diameter increases slightly toward the middle of the axle. This part ( 43 ) is located primarily inside rim ( 11 ). It covers, among other things, the area of the brake pad ( 34 ). The transition between the second ( 42 ) and third parts ( 43 ) forms the narrowest point between wheel rim ( 10 ) and disk brake protector ( 40 ). The part ( 42 ), relative to wheel rim ( 10 ), is located at the transition between rim dish ( 12 ) and rim ( 11 ). The transition is also located opposite rim openings ( 16 ).
The fourth part ( 44 ) forms the end of disk brake protector ( 40 ) that is oriented toward the middle of the axle. At least areawise, part 44 is approximately parallel to the interior rim shoulder ( 14 ), while the diameter visibly increases toward the middle of the axle. Part ( 44 ) may project over inner rim flange ( 15 ). Here it can terminate in an edge ( 45 ) that expands radially. The edge ( 45 ) increases dimensional stability and reduces the risk of injury when working on the brake system.
In the embodiment shown, the shortest distance between an outside contour of the disk brake protector ( 40 ) and an inside contour of the wheel rim ( 10 ) is in the vicinity of rim openings ( 16 ) of the wheel rim ( 10 ).
In the embodiment shown, the disk brake protector ( 40 ) is designed as a two-piece sheet metal body rotationally symmetrical to the wheel axis. Plastics with or without fabric inserts can be used as material. The disk brake protector ( 40 ) is divided centrally and parallel to its rotational axis. At a first parting line, for example, in cylindrical part ( 43 ) a hinge is located whose parts do not project radially beyond the outside contour of the entire part.
Disk brake protector ( 40 ) is fastened for example to the floating saddle ( 32 ) of the disk brake. For this purpose it is bolted radially and/or axially at several points ( 47 ) to floating saddle ( 32 ). The second parting line in disk brake protector ( 40 ) is located in the vicinity of floating saddle ( 32 ). Direct fastening to the extensive outside contour of floating saddle ( 32 ) enables the two half shells on floating saddle ( 32 ) to fit flush against one another. At the same time, with this type of fastening in a metal disk brake protector ( 40 ), the protector also serves as an additional cooling surface.
To facilitate replacement of brake pads ( 34 ), hold-downs ( 48 ) of brake pads ( 34 ) are located at disk brake protector ( 40 ) in the embodiment shown. As a result, the usual hold-down clamps required there are eliminated.
In the vicinity of hold-down ( 48 ) oriented toward the middle of the axle, a hook ( 49 ) is fastened to each half shell of disk brake protector ( 40 ), said hook fitting beneath a projection ( 33 ) of brake saddle ( 32 ) during assembly. With the aid of this hook ( 49 ) disk brake protector ( 40 ) can be temporarily secured during assembly before it is bolted to brake saddle ( 32 ).
Disk brake protector ( 40 ) provides especially good protection in commercial vehicles that can dump loose material, etc. to the side. For example, with side tipping of sand, gravel, asphalt, soil, and comparable construction materials the loose material as a rule passes through rim openings ( 16 ) of the wheels on the rear axle into the interiors ( 17 ) of the wheel rims located there. In rim interior ( 17 ) the loose material collects in front of disk brake protector ( 40 ), particularly in the first ( 41 ) and second ( 42 ) parts. Only a small amount of fine-grained loose material remains behind in chamber ( 51 ) behind disk brake protector ( 40 ), passing through the relatively small gap ( 52 ) between part ( 41 ) and the wheel hub ( 4 ). This amount falls into the lower interior area of disk brake protector ( 40 ) when the vehicle begins moving. From there it drops to the road. There are no obstacles to block the loose material since no parts of the brake system are located close to the road in the area below steering knuckle ( 1 ).
The loose material which is initially located between rim dish ( 12 ) and disk brake protector ( 40 ) is distributed through the interior ( 17 ) of the rim as the vehicle begins to move. A portion immediately falls through downwardly oriented rim openings ( 16 ) to the road. The remaining loose material is thrown out through rim openings ( 16 ) with increasing rpm. This also applies to gravel. Larger pieces of gravel do not enter annular gap ( 53 ) since they are forced into rim openings ( 16 ) through the narrow transitions between the second and third parts.
Smaller pieces of loose material that get between the third part ( 43 ) of disk brake protector ( 40 ) and the rim well cannot remain there since they are forced at an angle to the direction of travel by the airflow between the turning rim ( 11 ) and non-rotating disk brake protector ( 40 ). Secondly, in the embodiment shown, floating saddle ( 32 ) moves together with the disk brake protector ( 40 ) during all brake applications, likewise transversely to the direction of travel, opposite rim ( 11 ).
The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof. | A disk brake protector is provided for the brake disk of a motor vehicle wheel of the type with a perforated rim dish fastened directly or indirectly to the steering knuckle or axle housing and covering at least a part of the brake disk. The brake disk protector is located in the space between the disk brake and the wheel rim, covering at least a part of the brake disk friction ring surface and the radial friction ring circumferential surface. | 5 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of and is based upon and claims the benefit of priority under 35 U.S.C. §120 of U.S. Ser. No. 13/891,570, filed May 10, 2013, which is a continuation of U.S. Ser. No. 13/489,036, filed Jun. 5, 2012, now U.S. Pat. No. 8,467,410, issued Jun. 18, 2013, which is a continuation of U.S. Ser. No. 12/769,432, filed Apr. 28, 2010, now U.S. Pat. No. 8,228,941, issued Jul. 24, 2012, which is a continuation of U.S. Ser. No. 12/426,478, filed Apr. 20, 2009, now U.S. Pat. No. 7,768,985, issued Aug. 3, 2010, which is a continuation of U.S. Ser. No. 10/910,646 filed Aug. 4, 2004, now U.S. Pat. No. 7,542,453, issued Jun. 2, 2009, and claims the benefit of priority under 35 U.S.C. §119 from Japanese Patent Application No. 2004-003530, filed Jan. 8, 2004, the entire contents of each which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a wireless communication system, a wireless communication apparatus, a wireless communication method, and a computer program for performing mutual communication among a plurality of wireless stations like a wireless local area network (LAN). In particular, the present invention relates to a wireless communication system, a wireless communication apparatus, a wireless communication method and a computer program in which each communication station performs random access on the basis of carrier detection in accordance with the carrier sense multiple access with collision avoidance (CSMA) system.
[0004] To be more precise, the present invention relates to a wireless communication system, a wireless communication apparatus, a wireless communication method and a computer program for realizing random access in a communication environment in which a plurality of communication modes each having a transmission rate different from each other is intermixed. In particular, the present invention relates to a wireless communication system, a wireless communication apparatus, a wireless communication method and a computer program for realizing random access with a smaller overhead under a communication environment in which a plurality of communication modes each having a transmission rate different from each other is intermixed.
[0005] 2. Description of the Related Art
[0006] By setting up a LAN by connecting a plurality of computers to each other, the sharing of information such as a file and data, and the sharing of peripheral equipment such as a printer can be achieved, and further the exchange of information such as the transfer of electronic mail, data, contents and the like can be preformed.
[0007] Conventionally, a wired LAN connection using an optical fiber, a coaxial cable or a twisted-pair cable has been generally used. In this case, line construction work is needed, and it is difficult to set up a network easily. Furthermore, the laying of a cable is troublesome. In addition, after setting up a LAN, because the moving range of an apparatus is limited by the length of a cable, the wired LAN is inconvenient.
[0008] Accordingly, a wireless LAN is noticed as a system for releasing a user from LAN wiring of the wired system. Because almost all of wiring cables can be omitted in a work space such as an office in case of the wireless LAN, communication terminals such as personal computers (PC's) can be relatively easily moved.
[0009] In recent years, as the wireless LAN system has become high in speed and low in cost, the demand of the wireless LAN has been remarkably increased. In particularly, in the most recent days, for performing information communication among a plurality of electronic apparatus existing around a person by setting up a small-scale wireless network among them, the introduction of a personal area network (PAN) has been examined. For example, different wireless communication systems using frequency bands such as a 2.4 GHz band and a 5 GHz band which are not required to be licensed by the competent authorities to use have been defined.
[0010] As normal standards with regard to the wireless network, Institute of Electrical and Electronics Engineers (IEEE) 802.11 (see, for example, Non-Patent Document 1), High Performance Wireless Local Area Network (HIPERLAN)/2 (see, for example, Non-Patent Document 2 or Non-Patent Document 3), IEEE 802.15.3, Bluetooth communication and the like can be cited. The IEEE 802.11 standard includes various wireless communication systems such as an IEEE 802.11a standard and an IEEE 802.11b standard according to the differences of a wireless communication system, a frequency band to be used, and the like.
[0011] A method of providing an apparatus to be a control station called as an “access point” or a “coordinator” in an area to form a network under the generalized control by the control station for constituting a local area network by means of a wireless technique is generally used.
[0012] A wireless network locating an access point therein widely adopts an access control method based on a band reservation, in which when a certain communication apparatus performs an information transmission, the communication apparatus first reserves a band necessary for the information transmission at an access point for using a transmission path in order not to generate any collisions with the information transmission of another communication apparatus. That is, the wireless network performs a synchronized wireless communication in which each communication apparatus in the wireless network is synchronized with each other by locating the access point.
[0013] However, there is a problem in which the usability of a transmission path is reduced to half when an asynchronous communication is performed between communication apparatus on a transmission side and a reception side in a wireless communication system locating an access point therein because the wireless communication through the access point is certainly necessary.
[0014] On the other hand, as an another method for constituting a wireless network, an “ad-hoc communication” in which terminals are directly perform wireless communications with each other asynchronously has been devised. In particular, in a small-scale wireless network composed of a relatively few clients positioned near to each other, the ad-hoc communication, by which arbitrary terminals can directly perform asynchronous wireless communications with each other without using a specific access point, is considered to be suitable.
[0015] Because there is no central control station in an ad-hoc type wireless communication system, the system is suitable for constituting, for example, a home network composed of household electric apparatus. An ad-hoc network has the following features. That is, even if a terminal is in trouble or the power source thereof is off, a routing can be automatically changed, and consequently the network is difficult to break. Also, data can be transmitted relatively long distance while keeping a high-speed data rate by making a packet hop a plurality of times between mobile stations. Many development examples with regard to the ad-hoc system are known (see, for example, Non-Patent Document 4).
[0016] For example, in an IEEE 802.11 series wireless LAN system, an ad-hoc mode in which terminals operate in an autonomous distributed way in peer to peer without locating any control station is prepared.
[0017] Hereupon, it is necessary to avoid contention when a plurality of users accesses the same channel. As a typical communication procedure for avoiding the contention, carrier sense multiple access with collision avoidance (CSMA) is known. The CSMA indicates a connection method of performing multiple access on the basis of carrier detection. Because it is difficult to receive a signal which a terminal itself has performed an information transmission thereof in a wireless communication, a terminal starts own information transmission after confirming the nonexistence of information transmissions of the other communication apparatus not by a CSMA/collision detection (CD) method but by a CSMA/collision avoidance (CA) method for avoiding any collisions.
[0018] A communication method based on the CSMA/CA is described with reference to FIG. 11 . In the example shown in the drawing, it is supposed that there are four communication stations #0 to #3 under a certain communication environment.
[0019] Each communication station having transmission data monitors a medium state for a predetermined inter frame space, or a distributed coordination function (DCF) inter frame space (DIFS), from the last detection of a packet. When any media are clear, namely when there are no transmission signals, the communication station performs random backoff. Furthermore, when there are no transmission signals also in this period, a transmission right is given to the communication station.
[0020] In the shown example, after monitoring the medium state for an inter frame space DIFS, the communication station #0, which has the random backoff set to be shorter than that of the other peripheral stations, acquires the transmission right to be able to start a data transmission to the communication station #1.
[0021] At the data transmission, the communication station #0, or the transmission source, stores the information for a network allocation vector (NAV), and describes a period of time until the completion of the transaction of a data communication in a duration field of the header of a MAC frame (MAC header).
[0022] The communication station #1, or the transmission destination of the data frame, performs a reception operation of the data addressed to the local station for the duration of the Duration described in the MAC header. When the data reception has been completed, the communication station #1 returns an ACK packet to the communication station #0, or the data transmission source.
[0023] Moreover, the communication stations #2 and #3, which have received the data frame, and which are not the data transmission destinations, decode the description in the Duration field of the MAC header, and recognize the state in which the medium is occupied without monitoring the medium until the transaction ends to stop the transmission. The work is called that the peripheral stations “raise a NAV”, or the like. The NAV is effective over the duration indicated in the Duration field. For example, the duration until the communication station #1, or the reception destination, will return the ACK packet is specified as the Duration.
[0024] In such a way, according to the CSMA/CA system, contention is avoided while a single communication station acquires a transmission right, and while peripheral stations stop their data transmission operations during the duration of the data communication operation, and thereby collisions can be avoided.
[0025] Hereupon, it is known that a concealed terminal problem is generated in a wireless LAN network in an ad-hoc environment. The concealed terminal indicates a communication station which a communication station on one side of a communication party can hear but a communication station on the other side of the communication party cannot hear in case of performing a communication between certain specific communication stations. Because no negotiations can be performed between concealed terminals, there is the possibility that transmission operations collide with each other only by the above-mentioned CSMA/CA system.
[0026] A CSMA/CA in accordance with an RTS/CTS procedure is known as a methodology for solving the concealed terminal problem. Also in the IEEE 802.11, the methodology is adopted.
[0027] In an RTS/CTS system, a data transmission source communication station transmits a transmission request packet Request To Send (RTS), and starts a data transmission in response to the reception of a confirmation note packet Clear To Send (CTS) from a data transmission destination communication station. Then, when a concealed terminal receives at least one of the RTS and the CTS, the concealed terminal sets a transmission stop duration of the local station for the duration in which the data transmission based on the RTS/CTS procedure is expected to be performed, and thereby collisions can be avoided. The concealed terminal for a transmission station receives the CTS to set a transmission stop duration for avoiding the collision with a data packet. The concealed terminal for a reception station receives the RTS to stop the transmission duration for avoiding the collision with the ACK.
[0028] FIG. 12 shows an operation example of the RTS/CTS procedure. Incidentally, it is supposed that there are four communication stations #0 to #3 in the communication environment of the wireless communication environment. The communication stations #0 to #3 are supposed to be in the following state. That is, the communication station #2 can communicate with the adjacent communication station #0. The communication station #0 can communicate with the adjacent communication stations #1 and #2. The communication station #1 can communicate with the adjacent communication stations #0 and #3. The communication station #3 can communicate with the adjacent communication station #1. However, the communication station #2 is a concealed terminal for the communication station #1, and the communication station #3 is a concealed terminal for the communication station #0.
[0029] Each communication station having transmission data monitors a medium state for a predetermined inter frame space DIFS (DCF Inter Frame Space) until the communication station has detected a packet last. When the medium is clear, namely when the there are no transmission signals, during this period of time, the communication station performs random backoff. Moreover, when there are no transmission signals also during this period of time, the communication station is given a transmission right.
[0030] In the example shown in the drawing, the communication station #0, which has set the random backoff shorter than that of the other peripheral stations after the monitoring of the medium state for the inter frame space DIFS, can acquire the transmission right to start the data transmission to the communication station #1.
[0031] That is, the communication station #0, which transmits data, transmits a transmission request packet (RTS) to the communication station #1. On the other hand, the communication station #1 being the reception destination returns a confirmation note (CTS) to the communication station #0 after a shorter inter frame space Short IFS (SIFS). Then, the communication station #0 responds to the reception of the CTS packet to start the transmission of a data packet after the inter frame space SIFS. Moreover, when the communication station #1 completes the reception of the data packet, the communication station #1 returns an ACK packet with an inter frame space SIFS put between. Because the inter frame space SIFS is shorter than the inter frame space DIFS, the communication station #1 can transmit the CTS packet before the other stations, which acquires the transmission right after waiting for DIFS+random backoff in accordance with a CMSA/CA procedure.
[0032] At this time, the communication station #2 and the communication station #3, both located at positions where both of them can be concealed terminals from both of the communication station #0 and the communication station #1, performs control to detect the use of a transmission path by the reception of the RTS or the CTS, and not to perform any transmissions until the communication ends.
[0033] To put it more specific, the communication station #2 detects the start of the data transmission of the communication station #1 as the transmission source on the basis of an RTS packet, and decodes the Duration field described in the MAC header of the RTS packet, and further recognizes that the transmission path has been already used after that for the duration until the successive transmission of the data packet is completed (the duration until the end of ACK). Thereby, the communication station #2 can raise a NAV.
[0034] Moreover, the communication station #3 detects the start of the data transmission of the communication station #1 as the reception destination on the basis of the CTS packet, and decodes the Duration field described in the MAC header of the CTS packet, and further recognizes that the transmission path has been already used after that during the duration until the transmission of the successive data packet is completed (the duration until the ACK had ended). Thereby, the communication station #3 can raise a NAV.
[0035] In such a way, when a concealed terminal receives at least one of the RTS and the CTS, the concealed terminal sets the transmission stop duration of the local station for the duration to be expected to perform the data transmission based on the RTS/CTS procedure. Consequently, collisions can be avoided.
[0036] Now, the standardization of the IEEE 802.11g for supporting higher speed communication rate as a higher rank standard of the IEEE 802.11b being a wireless LAN specification using 2.4 GHz band has been advanced. A communication station in accordance with the IEEE 802.11g (hereinafter also referred to “high-grade communication station” simply) can also operate in accordance with the IEEE 802.11b, and can transmit a data packet also at a high-speed rate at which a conventional communication station in accordance with the IEEE 802.11b (hereinafter also referred to as “conventional station” simply) cannot perform any reception.
[0037] Hereupon, there is a problem of the coexistence of different communication systems, or a problem of the coexistence of the IEEE 802.11g and the IEEE 802.11b, both using the same band. That is, because the conventional station cannot receive a data packet to be transmitted at a high-speed rate, the conventional station cannot decode the Duration described in the MAC header, and cannot raise a NAV appropriately. Consequently, the conventional station cannot avoid collisions.
[0038] For example, in the example shown in FIG. 11 , the communication station #0 and the communication station #1, both being communication parties, can exchange a data packet at a high-speed rate in conformity with IEEE 802.11g. On the other hand, when the communication station #2 and the communication station #3 around the communication station #0 and the communication station #1 are conventional stations which do not conform to the IEEE 802.11g, the communication stations #2 and #3 cannot decode the Duration described in the MAC header as a result of being unable to receive the data packet. Consequently, there is the possibility that the communication stations #2 and #3 start their communication operation even in the duration of the Duration to generate a collision (see FIG. 13 ).
[0039] The present inventors consider that the problem of the coexistence of the IEEE 802.11g and the IEEE 802.11b is preferably solved by the setting of the IEEE 802.11g, being a higher rank standard, to assure ad-hoc compatibility.
[0040] For example, a method of performing the exchange of an RTS/CTS packet at a transmission rate at which a conventional station can receive the RTS/CTS packet before the transmission of a data packet in IEEE 802.11g can be considered (see FIG. 14 ). In this case, peripheral conventional stations decodes the Duration field described in the MAC header of the RTS/CTS packet, and recognize that the transmission path has already used for the duration until the completion of the transmission of the successive data packet after that (the duration until ACK ends). Thereby, the peripheral conventional stations can raise an NAV only for suitable duration. That is, the conventional stations cannot hear a data packet to be transmitted at a high-speed rate, but that turns to be no problem for avoiding a collision.
[0041] A procedure for securing a band in accordance with the above-mentioned procedure before the transmission of a data packet is generally called a virtual carrier sense.
[0042] However, in such a band securing procedure, the transmission of a data packet cannot be performed without performing the RTS/CTS procedure certainly not only in the case where the concealed terminal problem is generated, but also in the case where the concealed terminal problem does not exist. That is, the faster the transmission rate becomes, the larger the problem of an RTS/CTS overhead becomes. Also, the communication efficiency decreases by the degree of the problem.
Non-Patent Document 1: International Standard ISO/IEC 8802-11: 1999(E) ANSI/IEEE Std. 802.11, 1999 Edition, Part 11: Wireless LAN Medium Access Control (MAC) and PHYsical Layer (PHY) Specifications. Non-Patent Document 2: ETSI Standard ETSI TS 101 761-1 V1 3.1 Broadband Wireless Access Networks (BRAN); HIPERLAN Type 2; Data Link Control (DLC) Layer; Part1: Basic Data Transport Functions. Non-Patent Document 3: ETSI TS 101 761-2 V1. 3.1 Broadband Wireless Access Networks (BRAN); HIPERLAN Type 2; Data Link Control (DLC) Layer; Part 2: Wireless Link Control (RLC) sublayer. Non-Patent Document 4: C. K. Tho, “Ad-Hoc Mobile Wireless Network” (Prentice Hall PTR Corp.).
SUMMARY OF THE INVENTION
[0047] It is an object of the present invention to provide a superior wireless communication system, a wireless communication apparatus, a wireless communication method, and a computer program in which each communication station can suitably perform random access by the CSMA system on the basis of carrier detection.
[0048] It is another object of the present invention to provide a superior wireless communication system, a wireless communication apparatus, a wireless communication method, and a computer program which can realize random access in a communication environment in which a plurality of communication modes each having a different transmission rate to each other intermixes.
[0049] It is a further object of the present invention to provide a superior wireless communication system, a wireless communication apparatus, a wireless communication method, and a computer program which can realize random access with a smaller overhead in a communication environment in which a plurality of communication modes each having a different transmission rates to each other intermixes.
[0050] The present invention was made in consideration of the above-mentioned problems. A first aspect of the present invention is a wireless communication system in which a first communication station operating according to a first communication method and a second communication station capable of operating according to both of the first communication method and a second communication method coexist, wherein the second communication station transmits a packet composed of a first decoding portion capable of being received according to the first communication method, and a second decoding portion capable of being received according to the second communication method.
[0051] In this case, the “system” hereupon indicates a matter made of a plurality of logically aggregate apparatus (or logically aggregate functional modules realizing specific functions), and it does not matter whether each of the apparatus or the functional modules is in a single housing or not.
[0052] Moreover, the first communication method hereupon corresponds to, for example, the IEEE 802.11b being a wireless LAN specification using a 2.4 GHz band, and the second communication method corresponds to the IEEE 802.11g supporting a high-speed communication rate as a higher rank standard of the IEEE 802.11b.
[0053] Under such communication environment, there is a problem of the coexistence of the IEEE 802.11g and the IEEE 802.11b, both using the same frequency band.
[0054] For example, when a transmission and a reception of a packet is performed by random access, for example, the local station transmits a data packet as a data transmission station, and hopes that peripheral stations stop their communication operations for expected duration until an ACK is returned from a reception station. Moreover, when the RTS/CTS procedure is adopted, for example, the local station transmits an RTS or a CTS packet, and hopes that the peripheral stations stop their communication operations for the expected duration until the ACK is returned. However, when the second communication station operating in accordance with the higher rank standard performs a packet transmission according to the second communication method, a conventional station cannot receive the data packet transmitted at a high-speed rate, and cannot decode a duration described in a MAC header. Then, the conventional station cannot raise a NAV suitably, and cannot avoid a collision.
[0055] In the wireless communication system according to the present invention, a packet is composed of a first decoding portion capable of being received according to a first communication method, and a second decoding portion capable of being received according to a second communication method. The first decoding portion includes information related to a packet length and a transmission rate of the packet. Further, the first communication station that receives the packet calculates (packet length)/(transmission rate) on the basis of the packet length and the transmission rate of the packet, both capable of being obtained by decoding the first decoding portion, in order to obtain a residual reception period of time of the packet.
[0056] Then, when the second communication station performs a communication procedure according to the second communication method, the second communication station describes spoofed information of a packet length and a transmission rate in the first decoding portion like the indication of the duration for which communication operations of the other stations are stopped by (packet length)/(transmission rate) for the sake of the communication procedure. In such a case, the first communication station cannot receive the second decoding portion of the packet, but can avoid a collision by calculating the (packet length)/(transmission rate) on the basis of the description in the first decoding portion to raise the NAV for desired duration, and by stopping any data transmissions.
[0057] That is, in the wireless communication system according to the present invention, the second communication station performing a packet transmission spoofs about the information of the packet length and the transmission rate to be described in the first decoding portion in order that the first communication station receiving the packet may stop its communication operation for the duration until a communication transaction to be performed according to the second communication method ends. Thereby, the second communication station performing the second communication method realizes the so-called upper compatibility to the first communication station.
[0058] The duration until the communication transaction ends hereupon, specifically indicates the duration until an ACK transmission ends in a communication procedure preformed according to the second communication method. Moreover, when a packet transmission is performed in accordance with a communication procedure to perform multiple connections with a plurality of communication stations in the second decoding portion, the duration hereupon indicates the duration until all of the ACK transmissions performed in a time division multiplex from each remote station end. Moreover, the transmission of the ACK packet hereupon is not limited to the case of single ACK packet, but includes, for example, the case where the ACK packet is multiplexed with other kinds of packets such as an RTS packet, a CTS packet, and data packet to be transmitted.
[0059] For the second communication station described above realizes the mechanism of the ad-hoc compatibility, it is necessary for each second communication station to recognize that the information of the packet length and the transmission rate described in the first decoding portion is spoofed. Moreover, it is necessary that each second communication station mutually recognizes the spoofing of the information while the first communication station cannot know the spoofing of the information to operate in accordance with the description in the first decoding portion.
[0060] Accordingly, in the wireless communication system according to the present invention, the second communication station performing a packet transmission describes whether the spoofed information of a packet length and a transmission rate is described in the first decoding portion or not in a packet in a format which the second communication station capable of operating according to the second communication method can decode the spoofed information but the first communication station operating according to the first communication method cannot decode the spoofed information.
[0061] For example, the second communication station performing a packet transmission indicates whether the spoofed information of the packet length and the transmission ratc is described or not by means of a spoofed flag in the first decoding portion.
[0062] In this case, when the second communication station being a data reception side detects that the information of the packet length and the transmission rate in the first decoding portion of a packet received from another station is spoofed, the second communication station switches its reception method to the second communication method, and can perform the reception operation of the residual portion of the packet.
[0063] Moreover, the second communication station performing a packet transmission may be provided with a known second communication method decoding portion, in which all of the second communication stations can decode data, in a packet, and may describe whether spoofed information of a packet length and a transmission rate is described or not in the second communication method decoding portion for notifying the other second communication stations of the spoofing. For example, when a plurality of communication modes each having a transmission rate different from each other is defined as the second communication method, an actually used communication mode may be described in the second communication method decoding portion.
[0064] It is preferable that a second communication station performing a packet transmission transmits the second communication method decoding portion in a communication method in which all of the second communication stations can decode the data in the second communication method decoding portion but the first communication stations cannot decode the data. For example, the second communication station performing the packet transmission transmits the second communication method decoding portion at a low transmission rate of about 6 Mbps in order that all of the second communication stations can receive, but the second communication station performing the packet transmission performs the modulation processing of the second communication method decoding portion in accordance with a modulation system which each of the second communication stations knows but the first communication stations do not know. Thereby, only the second communication stations can demodulate the second communication method decoding portion to recognize that the first decoding portion is spoofed.
[0065] In such a case, a second communication station receiving the packet tries to decode the second communication method decoding portion by means of both of the first communication method and the communication method by which the first communication station cannot decode the second communication method decoding portion, and the second communication station can recognize that the first decoding portion is spoofed by the fact that the second communication method decoding portion can be decoded according to the latter method. Then, the second communication station can performs the reception processing of the second decoding portion in accordance with the communication mode obtained from the second communication method decoding portion.
[0066] For example, the second communication station locates the second communication method decoding portion before the second decoding portion in a packet. Then, when the second communication station describes the spoofed information of a packet length and a transmission rate for the first communication stations in the first decoding portion, the second communication station describes the information related to an actual packet length and a transmission rate in the second decoding portion in the second communication method decoding portion. In such a case, a second communication station receiving the packet can perform the reception operation of the second decoding portion after the second communication method decoding portion of the received packet on the basis of the information related to the packet length and the transmission rate described in the second communication method decoding portion.
[0067] A second communication station performing a packet transmission can make data to be able to be decoded by all of the second communication stations and to be unable to be decoded by the first communication stations by modulating the second communication method decoding portion in accordance with a modulation system which only each of the second communication station knows. For example, when the second communication station performs a phase modulation such as BPSK to the second communication method decoding portion, the second communication station may give a phase difference θ, which is jointly owned by the second communication station, to the location of a signal point (−1, 1), or may translation the signal point by the known quantity Ad. On the other hand, a second communication station receiving the packet performs phase demodulation in consideration of the phase shifts of the location of the signal point such as the phase difference −θ, the movement quantity −Δd and the like. Then, it can be known that the first decoding portion is spoofed by the fact that the second communication method decoding portion can be decoded.
[0068] Incidentally, in the case where a second communication station capable of operating according to the second communication method is located at a position far from a transmission source, a situation in which the second communication station can receive a second communication method decoding portion, which is transmitted at a low transmission rate, but cannot receive the second decoding portion, which is transmitted at a high-speed transmission rate, owing to an S/N, can be also supposed. In such a case, a second communication station receiving a packet tries to perform the reception operation of a second decoding portion on the basis of the information related to a packet length and a transmission rate described in the second communication method decoding portion of the received packet. When the second communication station cannot decode the second decoding portion, the second communication station may obtain a difference between a period of time (i.e. (packet length)/(transmission rate)) obtained from the spoofed packet length and the transmission rate described in the first decoding portion and a period of time (i.e. (packet length)/(transmission rate)) obtained from the packet and the transmission rate described in the second communication method decoding portion, and may restrain the transmission of a packet for a predetermined period of time.
[0069] The wireless communication system according to the present invention supposes, for example, a communication environment in which a conventional station operating in accordance with the IEEE 802.11b and a high-grade communication station operating in conformity with the IEEE 802.11g corresponding to a high-speed edition standard using the same band intermixedly operate.
[0070] In the wireless communication system according to the present invention, a packet to be transmitted is composed of a known fixed rate portion (hereinafter also referred to as “general decoding portion”) which all of the communication stations can decode, and an arbitrary rate portion (hereinafter also referred to as “high-grade decoding portion”) which possibly only a part of the communication station being at a high-grade can decode.
[0071] The general decoding portion of a packet generally describes a residual length of the packet and a rate at which residual packets are transmitted therein. Consequently, a communication station receiving the packet tries to receive the residual part of the packet by performing the reception operation of the packet at a specified rate for the duration of (packet length)/(rate).
[0072] In the present invention, a high-grade communication station performs a packet transmission at a transmission rate at which a conventional station cannot receive the packet. Also, when a conventional station is not desired to start a transmission for fixed duration, the information of a packet length and a rate in the general decoding portion is spoofed in order that the value of (packet length)/(rate) may be the duration for which the communication is desired to be stopped. For example, the value of (packet length)/(rate) should originally correspond to the reception duration of the residual portion of the packet. However, for example, the information is spoofed in order to be the duration for which a NAV such as the end of ACK should be raised.
[0073] Moreover, in this case, the high-grade communication station to be a communication party is needed to detect that these values described in the general decoding portion are spoofed for performing a correct reception operation without performing any malfunctions on the basis of the spoofed rate and the length. For this sake, a flag indicating the existence of spoofing is provided in the general decoding portion of a packet. Alternatively, a second communication method decoding portion, which all second communication stations can decode, is provided, and the fact that the general decoding portion is spoofed is described in the second communication method decoding portion. Then, after the general decoding portion has been transmitted, the high-grade communication station shifts to an arbitrary high grade rate mode, and transmits an actual data composed of a high-grade decoding portion.
[0074] When the conventional station receives a general decoding portion including the spoofed information of a packet length and a rate, the conventional station believes the packet length and the rate to receive the residual packet at a specified rate for a period of (packet length)/(rate). Because the rate and the packet length are different from ones at which the packet is actually transmitted, the conventional station cannot decode the packet correctly, and the packet is destroyed.
[0075] On the other hand, a high-grade communication station detects that the information of a packet length and a rate is spoofed by means of the flag in the general decoding portion. Alternatively, the high-grade communication station detects the spoofing owing to the capability of decoding the second communication method decoding portion. Then, when the general decoding portion is spoofed, the high-grade communication station shifts to the corresponding high grade rate mode, and receives the residual packet, i.e. a high-grade decoding portion. Thus, the high-grade communication station can decode actual data.
[0076] As described above, in the case where a packet length and a rate are used for setting a period of time during which all transmission starts are stopped, there are plurality of combinations of spoofed packet lengths and spoofed rates for showing the same period of time to the conventional station. On the other hand, there is a plurality of transmission modes as a high-speed communication rate sometimes. Accordingly, when a plurality of modes each including high-speed communication rate, a mode by which the residual packet is transmitted may be presumed by the setting of a rate.
[0077] Moreover, a second aspect of the present invention is a computer program described in a form capable of being read by a computer to execute on a computer system processing for a wireless communication operation in a wireless communication environment in which a first communication method and a second communication method coexist, the program including the steps of: generating a transmission packet composed of a first decoding portion and a second decoding portion, transmitting a first decoding portion of the transmission packet according to the first communication method, and transmitting a second decoding portion of the transmission packet according to the second communication method, receiving and analyzing a first decoding portion of a reception packet from another station, and receiving and analyzing a second decoding portion of the reception packet according to the second communication method.
[0078] The computer program according to the second aspect of the present invention defines a computer program described in the form capable of being read by a computer for realizing predetermined processing on a computer system. In other words, by installing the computer program according to the second aspect of the present invention into a computer system, a cooperative operation is exhibited on the computer system, and the computer system operates as a wireless communication apparatus. By building a wireless network by activating a plurality of such wireless communication apparatus, operations and advantages similar to those of the wireless communication system according to the first aspect of the present invention can be obtained.
[0079] According to the present invention, it is possible to provide a superior wireless communication system, a wireless communication apparatus, a wireless communication method and a computer program in which each communication station can suitably perform random access on the basis of a carrier detection according to a CSMA system.
[0080] Moreover, according to the present invention, it is possible to provide a superior wireless communication system, a wireless communication apparatus, a wireless communication method and a computer program in which random access can be realized in a communication environment in which a plurality of communication modes each having a transmission rate different from each other intermixes.
[0081] Moreover, according to the present invention, it is possible to provide a superior wireless communication system, a wireless communication apparatus, a wireless communication method and a computer program in which random access can be realized with a smaller overhead in a communication environment in which a plurality of communication mode, each having a transmission rate different from each other, intermixes.
[0082] According to the present invention, the coexistence of the IEEE 802.11g and the IEEE 802.11a/b, both using the same band, can be realized without passing an RTS/CTS procedure. Consequently, an overhead can be remarkably reduced.
[0083] Moreover, according to the present invention, the duration for an NAV can be flexibly set. Consequently, the throughput of a system can be improved.
[0084] Further objects, features and advantages of the present invention will be apparent by more detailed descriptions based on the embodiments of the present invention and the attached drawings, which will be described later.
BRIEF DESCRIPTION OF THE DRAWINGS
[0085] FIG. 1 is a view schematically showing a functional configuration of a wireless communication apparatus operating as a communication station in a wireless network according to one embodiment of the present invention;
[0086] FIG. 2 is a view for illustrating a mechanism of a priority transmission based on difference of inter frame spaces;
[0087] FIG. 3 is a view schematically showing one example of a frame configuration of a packet in the wireless network according to the present invention;
[0088] FIG. 4 is view schematically showing a variation of a packet structure in the wireless network according to the present invention;
[0089] FIG. 5 is a view showing a description example of Rate field in the IEEE 802.11a;
[0090] FIG. 6 is a flowchart showing a reception processing procedure in the case where a wireless communication apparatus 100 operates as a conventional station;
[0091] FIG. 7 is a flowchart showing a reception processing procedure in the case where the wireless communication apparatus 100 operates as a high-grade communication station;
[0092] FIG. 8 is a view showing one of communication operation examples based on CSMA/CA according to the present invention;
[0093] FIG. 9 is a view showing one of communication operation examples based on RTS/CTS according to the present invention;
[0094] FIG. 10 is a view showing one of communication operation examples based on RTS/CTS using Shot NAV according to the present invention;
[0095] FIG. 11 is a view showing a communication operation example base on CSMA/CA according to a conventional technology;
[0096] FIG. 12 is a view showing a communication operation example based on RTS/CTS according to a conventional technology;
[0097] FIG. 13 is a view showing a communication operation example based on CSMA/CA under a communication environment in which conventional stations and high-grade communication stations intermix according to a conventional technology;
[0098] FIG. 14 is a view showing a communication operation example based on RTS/CTS in conformity with the IEEE 802.11g according to a conventional technology;
[0099] FIG. 15 is a view showing one example of the internal configuration of a wireless reception unit 110 of a high-grade communication station capable of decoding a SIGNAL-2 portion;
[0100] FIG. 16 is a view showing one example of the frame configuration of a packet transmitted according to the second communication method; and
[0101] FIG. 17 is a view showing communication operation sequencing by which a plurality of reception stations replies by a time division response packet to a transmission packet from a transmission station.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0102] The embodiments of the present invention are described in detail hereinafter with reference to the attached drawings.
[0103] Channels of communication supposed in the present invention are wireless channels, and a network is built among a plurality of communication stations. Communication supposed in the present invention is a store and forward type traffic, and information is transferred per packet. Moreover, although each communication station is supposed to have a single channel in the following description, it is also possible to expand the description to the case where a transmission medium composed of a plurality of frequency channels, i.e. multi channels, is used.
[0104] In a wireless network according to the present invention, each communication station directly (randomly) transmits information in accordance with an access procedure based on a carrier sense multiple access (CSMA) (carrier detection multiple connection), and can build an autonomous distributed type wireless network. Moreover, in the wireless network according to the present invention, transmission control using channel resources effectively is performed by means of transmission (MAC) frame in a gentle time division multiplexing access structure. In this case, each communication station can perform an access system based on a time synchronization such as reserving a frequency band and setting a priority use duration.
[0105] One embodiment of the present invention supposes, for example, a communication environment in which both high-grade communication stations in conformity with the IEEE 802.11g corresponding to a high-speed edition standard using the same band and a conventional station in conformity with the conventional IEEE 802.11b intermixedly operate. That is, there are two kinds of communication terminals, that is; conventional stations which can transmit and receive only the packets modulated according to some limited modulation systems; and high-grade communication stations which can receive packets according to a high-grade system in addition to the modulation system by which the conventional station can receive packets.
[0106] The communication system in which the IEEE 802.11g and the IEEE 802.11b, both using the same band, intermix has a problem of coexistence. The reason is that, because the conventional station cannot receive a data packet transmitted at a high-speed rate, the conventional station cannot decode the Duration described in a MAC header to raise an NAV suitably, and consequently cannot avoid a collision. The present invention solves the coexistence problem by securing that the higher rank standard IEEE 802.11g assures the conventional standard IEEE 802.11b of the so-called upper compatibility. The solving method will be described later.
[0107] FIG. 1 schematically shows a functional configuration of a wireless communication apparatus operating as a communication station in a wireless network according to one embodiment of the present invention. A wireless communication apparatus 100 shown here can form a network while avoiding a collision in the same wireless system by performing a channel access effectively. The wireless communication apparatus 100 is either of a conventional station in conformity with the IEEE 802.11a/b as a first communication method and a high-grade communication station in conformity with the IEEE 802.11g as a second communication method.
[0108] As shown in FIG. 1 , the wireless communication apparatus 100 is composed of an interface 101 , a data buffer 102 , a central control unit 103 , a packet generation unit 104 , a wireless transmission unit 106 , a timing control unit 107 , an antenna 109 , a wireless reception unit 110 , a packet analysis unit 112 , and an information storage unit 113 .
[0109] The interface 101 performs exchanges of various kinds of information between the wireless communication apparatus 100 and an external apparatus (such as a personal computer, though not shown) connected to the wireless communication apparatus 100 .
[0110] The data buffer 102 is used for temporarily storing the data transmitted from the external apparatus connected to the wireless communication apparatus 100 through the interface 101 , and the data received through a wireless transmission path before transmitting the data through the interface 101 .
[0111] The central control unit 103 unitarily performs the administration of series of information transmission and reception processing in the wireless communication apparatus 100 and the access control of transmission paths. Basically, the central control unit 103 sets a timer of backoff to operate over a random period of time on the basis of CSMA while monitoring the states of the transmission paths, and performs access contention of acquiring a transmission right in the case where no transmission signals exist during this period of time.
[0112] The present embodiment adopts a mechanism of a priority transmission in the access contention to realize flexible QoS (see FIG. 2 ). For example, the wireless communication apparatus 100 takes a normal operation mode after a packet transmission of another station or at the time of low traffic priority, and sets an inter frame space IFS to a longer DIFS, and further sets the random backoff. On the other hand, in case of performing the transmission of CTS successively to RTS from another station, in case of performing the transmission of a data packet successively to CTS, and in case of the transmission of ACK, the wireless communication apparatus 100 sets the inter frame space IFS to a shorter SIFS, which enables a transmission prior to the other stations performing normal transmission operations.
[0113] The packet generation unit 104 generates a packet signal to be transmitted from the local station to a peripheral station. The packet hereupon includes a transmission request packet RTS from a communication station being a reception destination, a confirmation response packet CTS to the transmission request packet RTS, an ACK packet and the like as well as a data packet. For example, a data packet is generated by taking out of the transmission data stored in the data buffer 102 for a predetermined length to be set as a payload.
[0114] In a MAC layer of a communication protocol, a MAC frame is configured by adding a MAC header to a payload, and furthermore a PHY header is added at a PHY layer to be a final transmission packet structure. In the present embodiment, the PHY header constitutes a first decoding portion, and the MAC frame portion constitutes a second decoding portion. The configuration of a packet signal will be described later.
[0115] The wireless transmission unit 106 and the wireless reception unit 110 correspond to an RF layer and the PHY layer in the communication protocol.
[0116] The wireless transmission unit 106 performs the wireless transmission processing of a packet signal according to a predetermined modulation system and a transmission rate. To put it more specific, the wireless transmission unit 106 includes a modulator for modulating a transmission signal according to the predetermined modulation system, a D/A converter for converting a digital transmission signal into an analog signal, an up-converter for performing the frequency conversion of an analog transmission signal to up-convert the analog transmission signal, a power amplifier (PA) for amplifying the electric power of the up-converted transmission signal (all of them are not shown). The wireless transmission unit 106 performs the wireless transmission processing at a predetermined transmission rate.
[0117] Moreover, the wireless reception unit 110 performs the wireless reception processing of the packet signal from another station. To put it more specific, the wireless reception unit 110 is composed of a low noise amplifier (LNA) for amplifying the voltage of a wireless signal receiving from another station through the antenna 109 , a down-converter for down-converting the voltage-amplified reception signal by frequency conversion, an automatic gain controller (AGC), an A/D converter for performing the digital conversion of an analog reception signal, a demodulator for performing a synchronous processing for acquiring a synchronization, a channel estimation, a demodulation processing by means of a demodulation system such as OFDM, and the like (all of them are not shown).
[0118] In the case where the wireless communication apparatus 100 conforms to the IEEE 802.11a/b as the first communication method, the wireless transmission unit 106 and the wireless reception unit 110 respectively perform a transmission and a reception of a packet according to a modulation system and a transmission rate in conformity with a wireless LAN standard. Moreover, in the case where the wireless communication apparatus 100 conforms to the IEEE 802.11g as the second communication method, it is possible for the wireless communication apparatus 100 to perform a transmission and reception of a packet according to a modulation system and a transmission rate in conformity with the IEEE 802.11a/b. In addition, the wireless communication apparatus 100 can perform a transmission and a reception of a packet at a transmission rate inherent to the IEEE 802.11g (i.e. a transmission and a reception unable to be received by the IEEE 802.11a/b). In the latter case, the first decoding portion of a packet composed of the PHY header is transmitted and received at a transmission rate capable of being received by the IEEE 802.11a/b, but the second decoding portion composed of the MAC frame is transmitted and received at a transmission rate in conformity with the IEEE 802.11g.
[0119] The antenna 109 performs the wireless transmission of a signal to another wireless communication apparatus on a predetermined frequency channel, or collects a signal transmitted from another wireless communication apparatus. The present embodiment is provided with a single antenna, and it is supposed that a transmission and a reception cannot simultaneously performed in parallel.
[0120] The timing control unit 107 controls a timing for transmitting and receiving a wireless signal. For example, the timing control unit 107 controls its own packet transmission timing, the transmission timing of each packet (such as RTS, CTS, data, and ACK) in conformity with the RTS/CTS system (setting of an inter frame space IFS and the backoff), the setting of the NAV at the time of reception of a packet addressed to another station, and the like.
[0121] The packet analysis unit 112 analyzes the packet signal which can be received from another station. In the present embodiment, the packet is composed of a first decoding portion and a second decoding portion. The details of a packet decoding method will be described later.
[0122] The information storage unit 113 stores an execution procedure instruction of a series of access control operations to be executed by the central control unit 103 , and information obtained from an analysis result of a reception packet.
[0123] As described above, in a wireless network of the present embodiment, there are two kinds of communication stations of conventional stations capable of the transmission and the reception of a packet modulated according to some limited modulation systems, and high-grade communication stations capable of the reception in conformity with a high-grade system in addition to the modulation systems in which the conventional stations can perform receptions. There is a coexistence problem in a communication system in which the IEEE 802.11g and the IEEE 802.11b using the same band intermix. The present embodiment solves this problem by making the high-grade communication stations provide the so-called ad-hoc compatibility to the conventional stations. The details of the solution will be described.
[0124] FIG. 3 schematically shows the configuration of a packet which the wireless communication apparatus 100 operating as a communication station in the wireless network of the present embodiment transmits and receives.
[0125] In a MAC layer of the communication protocol, a MAC frame is constituted by adding a MAC header to a payload (corresponding to an IP packet). Moreover, in a PHY layer, a PHY header is added to the MAC frame to be a final transmission packet structure. The PHY header constitutes a first decoding portion, and the MAC frame portion constitutes a second decoding portion. As shown in FIG. 3 , a packet is composed of a physical layer convergence protocol (PLCP) preamble portion and a SIGNAL portion as the PHY header, and the MAC frame. The MAC frame is composed of the MAC header and a data portion.
[0126] The PHY header corresponds to the first decoding portion, and the MAC frame corresponds to the second decoding portion.
[0127] In the case where the transmission station of a packet is a conventional station in conformity with the IEEE 802.11a/b, both of the PHY header and the MAC frame are transmitted according to the first communication method.
[0128] Moreover, in the case where the transmission station of a packet is a high-grade communication station in conformity with the IEEE 802.11g, the communication station transmits the whole packet according to the first communication method when the communication station transmits the packet to a conventional station. On the other hand, when the high-grade communication station transmits a packet to a high-grade communication station, the transmitting communication station transmits only the first decoding portion of the packet according to the first communication method, by which all communication stations can receive the first decoding portion, and can transmit the second decoding portion of the packet including the data portion according to the second communication method having a higher transmission rate.
[0129] On the transmission side of the shown packet, first, the PLCP preamble portion is transmitted as the head of the packet, and next, the SIGNAL portion and the MAC frame are transmitted.
[0130] The PLCP preamble portion includes elements such as a signal detect (Signal Detect) and a channel estimation (Channel Estimation). Consequently, a peripheral station knows the existence of a signal from a communication station by receiving the PLCP preamble portion, and performs the estimation of a transmission channel and the like.
[0131] The communication station knowing the transmission of the signal by the detection of the PLCP preamble portion starts the reception of the subsequently arriving SIGNAL portion. Because the SIGNAL portion is transmitted according to the first communication method, which all communication station know, both of the conventional stations and the high-grade communication stations can receive the SIGNAL portion.
[0132] The SIGNAL portion includes a transmission rate (Rate) of the subsequent MAC frame, the length (Length) of a residual data of the packet such as the MAC frame, parity (Parity), a reserved area (Reserve) and the like.
[0133] The MAC frame is modulated according to the transmission rate specified by the transmission rate (Rate) of the SIGNAL portion. The MAC frame is composed of the MAC header and the data portion corresponding to the payload. The MAC header describes an address (RX Address) of the reception station of the packet, Duration specifying the duration in which the stations other than the reception station severally should raise the NAV.
[0134] A communication station which can normally receive and decode the MAC header portion compares the address of the local station with the reception address. When they coincide with each other, the communication station receives the residual portion of the packet at a specified rate for the duration of (packet length)/(transmission rate) in accordance with the transmission rate (Rate) and the packet length (Length) information, both described in the SIGNAL portion. Moreover, when its own address and the received address do not coincide with each other, the communication station raises the NAV for the Duration described in the MAC header, and restrains any transmissions from the local station. The procedure for securing a band in accordance with the procedure mentioned above is generally called as virtual carrier sense.
[0135] Now, when a transmission station of a packet being a high-grade communication station according to the IEEE 802.11b performs the transmission of the packet to a high-grade communication station, the transmission station transmits only the first decoding portion according to the first communication method, which all communication stations can receive, but transmits the second decoding portion including the data portion according to the second communication method having the higher transmission rate. Consequently, because the conventional stations cannot receive the second decoding portion, the conventional stations cannot decode the Duration described in the MAC header. Consequently, there is a problem in which the conventional stations cannot know the duration for which the conventional stations should severally raise the NAV.
[0136] Conventionally, the description of the Duration in the MAC header has been used for band securing. However, for realizing the coexistence of the IEEE 802.11g and the IEEE 802.11a/b, a mechanism is needed for the conventional stations to recognize the duration for which the conventional stations should severally raise the NAV on the basis of other information without using the description of the Duration.
[0137] Accordingly, the present embodiment prepares a mechanism in which, even if a packet is transmitted according to the IEEE 802.11g as the second communication method, the first decoding portion, which all communication stations can certainly receive, is provided, and the duration corresponding to the NAV is specified by means of the first decoding portion.
[0138] As shown in FIG. 3 , the first decoding portion is composed of the PHY header of a packet. Then, the period of time corresponding to the Duration is described in a pseudo-way in the SIGNAL portion, which all communication stations can receive, by using the information of the transmission rate (Rate) and the packet length (Length). That is, the information of the transmission rate (Rate) and the packet length (Length) is spoofed so that the value of (packet length)/(rate) may be equal to the duration for which any communications are desired to be stopped.
[0139] As a result, the conventional stations severally set the packet length and the transmission rate, which are different from the fact, and perform the reception for a period of time corresponding to the Duration. The actual packet is not transmitted over the period of (packet length)/(rate), but the conventional stations do not start their transmissions for the duration corresponding to Duration. As a result, the conventional stations restrain their transmissions and continue their receiving for the duration for which communications are desired to be stopped.
[0140] Incidentally, in this case, after the conventional stations have performed the receptions for the spoofed period of (packet length)/(rate), CRC errors are certainly generated. The IEEE 802.11 has a rule in which, when a CRC error is generated in the data portion, any receptions are restrained for a period of time EIFS longer than a normal inter frame space DIFS. Accordingly, it is desirable to perform the spoofing so that a period of time obtained by subtracting “EIFS-DIFS” from the duration for which the receptions are truly desired to be continued as the period of (packet length)/(rate) for avoiding the conventional station being always unfairly treated.
[0141] As described above, the high-grade communication stations use the information of the transmission rate (Rate) and the packet length (Length) so as to describe the period of time corresponding to Duration in the first decoding portion in a pseudo-way, and thereby the high-grade communication stations supply the so-called ad-hoc compatibility to the conventional stations. In this case, for a communication procedure according to the high-grade communication method in conformity with the IEEE 802.11g is being performed, the conventional stations avoid any collisions, and thereby a normal network operation can be realized.
[0142] Moreover, in the case where the high-grade communication stations use a high-speed transmission rate which the first communication method cannot deal with, a value which the first communication method can deal with should be set in the transmission rate (Rate) field of the SIGNAL portion as the spoofing in order that the conventional stations can correctly decode the first decoding portion. In this case, the packet length (Length) should be also spoofed in accordance with the spoofed transmission rate (Rate) value.
[0143] As described above, the spoofing is performed in the SIGNAL portion in order that the value of (packet length)/(rate) may be equal to the duration for which the conventional stations are desired to stop communications. Hereupon the duration for which the conventional stations are desired to stop communications, in short, indicates the duration until a communication transaction performed according to the second communication method ends. To put it more specific, the duration indicates the duration until an ACK transmission in a communication procedure performed according to the second communication method ends. Moreover, when packet transmissions are performed in a communication procedure for performing multiple connections with a plurality of communication stations in a MAC frame according to the second communication method, the above-mentioned duration corresponds to the duration until all of the ACK transmissions performed from each of the remote stations in time division multiplex end. Incidentally, Japanese Patent Application No. 2003-297919 which has been assigned to the present applicant, discloses a communication system in which a transmission station transmits a data frame addressed to a plurality of reception stations by means of space division multiple access (SDMA) and each reception station replies ACK in time division multiplex. Moreover, the transmission of the ACK packet hereupon is not limited to the transmission of the ACK packet alone, but includes the case where the ACK packet is multiplexed by the other kinds of packets such as an RTS packet, a CTS packet and a Data packet to be transmitted.
[0144] Hereupon, it is necessary for a high-grade communication station being a communication party to detect that the values of spoofed Rate and Length described in the first decoding portion are spoofed for performing a correct reception operation without performing any malfunctions based on the spoofed Rate and Length. That is, for realizing the mechanism of the ad-hoc compatibility in a high-grade communication station, it is needed for each high-grade communication station to recognize that the information of a packet length and a transmission rate described in the first decoding portion is spoofed. Moreover, for preventing the conventional stations from knowing that the information is spoofed, only the high-grade communication stations mutually recognize the fact, and the first communication stations should operate in accordance with the description in the first decoding portion.
[0145] In the embodiment shown in FIG. 3 , for example, a flag of one bit indicating the existence of the spoofing is prepared in the reserved area (Reserve) of the SIGNAL portion. Then, when a high-grade communication station detect that the information of the packet length and the rate is spoofed by means of the flag in the first decoding portion, the high-grade communication station shifts to the corresponding high grade rate mode, and can decode actual data by receiving the residual packet, i.e. a high-grade decoding portion. In this case, the high-grade communication station destroys the information of the packet length and the rate read from the SIGNAL portion of the received packet.
[0146] In the case where only a single communication method (communication mode) is defined in the second communication method for performing the packet transmission and the reception at a high-speed transmission rate, the shift of the communication method can be specified only by means of the spoofed flag of one bit as described above with FIG. 3 being referred to. On the contrary, in the case where the second communication method includes a plurality of transmission modes, it becomes impossible to specify a transmission mode only by means of the spoofed flag of one bit.
[0147] The simplest way of specifying one of a plurality of transmission modes as described above is to add a field for specifying a transmission mode in a packet. FIG. 4 shows a variation of the packet structure shown in FIG. 3 . In the shown example, a SIGNAL-2 portion (high throughput (HT) PHY portion) is furthermore added after the SIGNAL portion in a packet transmitted according to the second communication method.
[0148] In the shown example, the SIGNAL-2 portion includes a field describing a true transmission rate (True Rate) and a true packet length (True Length), and a field describing a mode parameter value (Mode Parameter). Because the SIGNAL-2 portion is transmitted at a fixed transmission rate at which all high-grade communication stations can perform a reception, the high-grade communication station which has received the packet performs an reception operation in accordance with the true transmission rate (True Rate) and the true packet length (True Length). Moreover, conventional stations cannot decode the SIGNAL-2 portion, and set their reception duration on the basis of the rate and the length described in the SIGNAL portion.
[0149] Now, it is needed for each of the high-grade communication stations to recognize the spoofing in the way that the conventional stations cannot know the spoofing of the transmission rate and the packet length in the SIGNAL portion, and the conventional stations should operate in conformity with the description in the SIGNAL portion. For the sake of this, a packet is transmitted according to the communication method in which all high-grade communication stations can decode the SIGNAL-2 portion (HT-SIGNAL portion) as the second communication method decoding portion and the conventional stations cannot decode the SIGNAL-2 portion.
[0150] For example, the SIGNAL-2 portion is transmitted at a low transmission rate of about 6 Mbps for all high-grade communication stations can receive the SIGNAL-2 portion, and a modulation processing of the SIGNAL-2 portion is performed according to a modulation system which each of the high-grade communication stations know but the first communication stations do not know. Thereby, only the high-grade communication stations can demodulate the SIGNAL portion to recognize that the SIGNAL portion is spoofed.
[0151] In such a case, a high-grade communication station receiving the packet tries to decode the SIGNAL-2 portion in accordance with both of the first communication method and a communication method which the first communication stations cannot decode, and can recognize that the SIGNAL portion is spoofed by the fact that the SIGNAL-2 portion can be decoded according to the latter method. Then, the high-grade communication station can perform the reception processing of the second decoding portion according to the communication mode obtained from the SIGNAL-2 portion.
[0152] The SIGNAL-2 portion is located before the MAC frame being the second decoding portion. Consequently, in the case where the information of a packet length and a transmission rate is spoofed in the first decoding portion, a high-grade communication station receiving the packet can perform the reception operation of the second decoding portion after the SIGNAL-2 portion on the basis of the true packet length (True Length) and the true transmission rate (True Rate) describe in the SIGNAL-2 portion.
[0153] A high-grade communication station performing a packet transmission modulates the second communication method decoding portion according to a modulation system known only by each of the high-grade communication stations, and thereby it can be realized that all of the high-grade communication stations can decode the second communication method decoding portion, and that conventional stations cannot decode the second communication method decoding portion. For example, in case of performing a phase modulation of the SIGNAL-2 portion such as BPSK, a phase difference 0, which second communication stations jointly own, may be given to a signal point location, or a signal point may be translated by a known quantity δd. On the other hand, a high-grade communication station receiving the packet performs the phase demodulation of the packet in consideration of the phase shift of the signal point location such as the phase difference −θ or the movement quantity −Δd. Then, the high-grade communication station can know the spoofing of the first decoding portion by the fact that the SIGNAL-2 portion could be decoded.
[0154] FIG. 16 shows an example of the inner structure of the wireless reception unit 110 in this case. The wireless reception unit 110 is composed of an RF unit and a PHY portion. The PHY portion is composed of a first demodulation unit, a second demodulation unit, and a reception processing unit for processing reception data which correctly demodulated by either of these demodulation units.
[0155] The reception processing unit notifies the first demodulation unit of the modulation system (transmission rate) obtained from the first decoding portion. The first demodulation unit supposes that the first decoding portion is not spoofed, and demodulates the signal after that according to the modulation system (transmission rate) described in the first decoding portion by the signal point location same as that of the first decoding portion.
[0156] The second demodulation unit supposes that the SIGNAL-2 portion follows the first decoding portion, and demodulates the SIGNAL-2 portion according to a known modulation system (transmission rate) by the signal point location whose phase has been rotated by 90 degrees.
[0157] The SIGNAL-2 portion has a fixed length. Consequently, when it becomes clear that the portion is the SIGNAL-2 portion after the demodulation of a predetermined length of the SIGNAL-2 portion, it is found that the first decoding portion is spoofed. If not so, it is found that the first decoding portion is not spoofed. In the latter case, the second demodulation unit continues the demodulate at the unrotated signal point location by the first demodulation unit. Thereby, it is possible to suggest whether the spoofing is performed or not without providing any spoofed flag in the reserved area (Reserve) of the first decoding portion.
[0158] Incidentally, a modulation system for providing a phase difference to a signal point on a constellation to perform mapping is, for example, disclosed in Japanese Unexamined Patent Publication No. Hei 11-146025.
[0159] The high-grade communication station can decode the second decoding portion (see DATA portion of FIG. 16 ) in principle, as described above. However, it is supposed that the second decoding portion cannot be decoded when the distance between communication terminals is large, or when a MIMO communication is performed. In such cases, it is possible to estimate how long a packet transmission terminal directs the other terminals to restrain their transmissions by using the first decoding portion (SIGNAL portion in FIG. 16 ) and the second communication method decoding portion (HT-SIGNAL portion in FIG. 16 ), both modulated at a fixed low-speed rate.
[0160] The value of (packet length)/(transmission rate) calculated on the basis of the description in the SIGNAL portion as the first decoding portion is the duration until the reception of ACK in FIG. 16 is completed. Moreover, the value of (True Length)/(True Rate) calculated on the basis of the HT-SIGNAL portion as the second communication method decoding portion corresponds to the duration until the transmission of a true packet is completed. The difference between the two (Length)/(Rate) (by adding EIF-DIFS in FIG. 16 ) is a value corresponding to an NAV indicating how long the packet transmission terminal directs the other terminals to restrain their transmissions.
[0161] The method of adding the field (SIGNAL-2 portion or HT-SIGNAL portion) as shown in FIG. 4 for specifying a transmission mode to a packet for enabling the mutual notification of the transmission mode among high-grade communication stations is simple, but the decrease of the overhead and the communication efficiency caused by the transmission data becomes a problem.
[0162] Now, as described above, in the case where RATE and Length in the SIGNAL portion are set in a pseudo-way, there are a plurality of spoofed combinations of the packet length and the rate for indicating the same period of time. For example, because the period of time necessary for transmitting 1200 bits at 6 Mbps and the period of time necessary for transmitting 2400 bits at 12 Mbps are the same, a reception station does not care which period of time is set as Rate.
[0163] However, in the case where a high-grade communication station uses a high-speed transmission rate which the first communication method cannot deal with, it is necessary that a value corresponding to the first communication method is spoofed in the transmission rate (Rate) field of the SIGNAL portion for enabling the conventional stations to decode the first decoding portion correctly. In this case, it is needed to perform the spoofing by adjusting the value of the packet length (Length) in order to be able to obtain a desired Duration value according to the spoofed transmission rate (Rate) value.
[0164] In the example shown in FIG. 3 , in the case where a spoofed flag is set in the SIGNAL portion being the first decoding portion, the high-grade communication stations destroy the information of Rate in the SIGNAL portion as being spoofed. On the other hand, in the example shown in FIG. 4 , it is possible to indicate which mode the successive high-grade modulation system takes by using the information of True Rate described in the SIGNAL-2 portion.
[0165] FIG. 5 shows a description example of the Rate field in the IEEE 802.11a. As shown in FIG. 5 , the IEEE 802.11a sets eight transmission rates of 6 Mbps, 9 Mbps, 12 Mbps, 18 Mbps, 24 Mbps, 36 Mbps, 48 Mbps and 54 Mbps. In the Rate field, transmission rates are expressed by means of four bits. When a spoofed flag is set, it is possible to assign the definition of the Rate field on a standard to the specifying of an actual high-speed transfer mode.
[0166] In the example shown in FIG. 5 , though the Rate field is four bits, all of the LSB's are set to be 1. Consequently, it is possible to specify each of 3 bits, i.e. eight modes can be specified. Moreover, the IEEE 802.11b being a conventional standard includes the least upper bound of settable packet length (Length). Consequently, when a higher rank rate is used for spoofing, the Length field is lacked. Then, there is a problem in which a sufficient value of Duration cannot be secured for (packet length (Length))/(rate (Rate)) (namely, an NAV of a long duration cannot be spoofed). Accordingly, actually four rates of 6 Mbps, 9 Mbps, 12 Mbps, and 18 Mbps are used for the specification of the high-speed transfer mode for enabling the setting of large value Duration (=(Length)/(Rate)). Because there is the possibility that there is a conventional station which, when a Length exceeding the least upper bound is set, recognizes the information as an error and destroys the information, the definition is provided (the IEEE 802.11a indicates the Length information by bits, and the IEEE 802.11b indicates the Length information by periods of time).
[0167] Incidentally, because the IEEE 802.11n supposes a system using a multi-input multi-output (MIMO) communication and a system expanding a communication use band as a high-speed transmission, a plurality of transmission modes can exist according to the combination of the number of antennas used for the MIMO communications and communication use bands. In such a case, the transmission mode may be notified among the high-grade communication stations by means of any one of the above-described methods.
[0168] Hereupon, the MIMO communication indicates a technique for achieving the increase of a transmission capacity and the improvement of a communication speed by realizing space division multiplexing, i.e. a plurality of logically independent transmission paths, by providing a plurality of antenna elements both at the transmitter side and at the receiver side. Because the MIMO communication uses the space division multiplexing, frequency usability is good.
[0169] Next, a reception processing procedure of the wireless communication apparatus 100 in the wireless network according to the present embodiment is described.
[0170] FIG. 6 shows a reception processing procedure in the form of a flowchart in the case where the wireless communication apparatus 100 operates as a conventional station. Such a processing procedure is actually realized in a form in which the central control unit 103 executes the instruction executing program stored in the information storage unit 113 .
[0171] When the wireless communication apparatus 100 receives a PLCP preamble portion in step S 1 , the wireless communication apparatus 100 successively receives the SIGNAL portion of the PHY layer in step S 2 .
[0172] Then, the wireless communication apparatus 100 decodes the information of the transmission rate (Rate) and the packet length (Length) described in the SIGNAL portion in step S 3 , and calculates the reception duration determined by (packet length)/(transmission rate).
[0173] Next, the wireless communication apparatus 100 receives a MAC header portion at the transmission rate specified by RATE in the SIGNAL portion in step S 4 . Now, when the wireless communication apparatus can decode the reception destination address on the basis of the MAC header in step S 5 , the wireless communication apparatus 100 compares the reception destination address with the local station address in step S 6 . Then, when both the addresses coincide with each other, the wireless communication apparatus 100 performs the reception processing for the packet length specified by the Length of the SIGNAL portion in step S 7 .
[0174] Moreover, when the reception destination address and the local station address do not coincide with each other in step S 6 , the wireless communication apparatus 100 raises an NAV for the Duration determined by (packet length)/(transmission rate), and restrains its transmission in step S 8 .
[0175] Moreover, when the wireless communication apparatus 100 cannot decode the reception destination address on the basis of the MAC header in step S 5 , the wireless communication apparatus 100 performs reception processing for a packet length specified by the Length of the SIGNAL portion in step S 7 .
[0176] Moreover, FIG. 7 shows a reception processing procedure in the form of a flowchart when the wireless communication apparatus 100 operates as a high-grade communication station. Such a processing procedure is actually realized in the form in which the central control unit 103 executes the instruction executing program stored in the information storage unit 113 .
[0177] When the wireless communication apparatus 100 receives a PLCP preamble portion in step S 11 , the wireless communication apparatus 100 successively receives the SIGNAL portion of the PHY layer in step S 12 .
[0178] Then, the wireless communication apparatus 100 , for example, refers to the spoofed flag in the Reserve field to judge whether the information of the transmission rate (Rate) and the packet length (Length) is spoofed or not in step S 13 .
[0179] Alternatively, the wireless communication apparatus 100 judges whether the SIGNAL-2 portion is provided successively to the SIGNAL portion or not. Thereby, the wireless communication apparatus judges whether the information of the transmission rate (Rate) and the packet length (Length) is spoofed or not in step S 13 . In this case, the wireless communication apparatus 100 tries to demodulate the SIGNAL-2 portion according to the modulation system which each of the high-grade communication stations knows but the first communication stations do not know in parallel with the wireless communication apparatus 100 demodulates the signal after the SIGNAL-2 portion according to the modulation system (transmission rate) described in the SIGNAL portion. Then, the wireless communication apparatus 100 can recognized that the SIGNAL portion is spoofed on the basis of the fact the wireless communication apparatus 100 can decode the SIGNAL-2 portion according to the latter modulation system.
[0180] Now, when the spoofed flag is not set, the wireless communication apparatus 100 can recognize that the packet is transmitted at the transmission rate at which the conventional stations can receive the packet. Then, the wireless communication apparatus 100 decodes the information of the transmission rate (Rate) and the packet length (Length) described in the SIGNAL portion in step S 14 , and calculates the reception duration determined by (packet length)/(transmission rate).
[0181] Next, the wireless communication apparatus 100 receives the MAC header portion at the transmission rate specified by the RATE in the SIGNAL portion in step S 15 . Now, when the wireless communication apparatus can decode the reception destination address on the basis of the MAC header in step S 16 , the wireless communication apparatus 100 compares the reception destination address with the local station address in step S 17 . Then, when both the addresses coincide with each other, the wireless communication apparatus 100 performs the reception processing for the packet length specified by the Length of the SIGNAL portion in step S 18 .
[0182] Moreover, when the reception destination address and the local station address do not coincide with each other in step S 17 , the wireless communication apparatus 100 raises an NAV for the Duration specified by the MAC header, and restrains its transmission in step S 19 .
[0183] Moreover, when the wireless communication apparatus 100 cannot decode the reception destination address on the basis of the MAC header in step S 16 , the wireless communication apparatus 100 performs reception processing for a packet length specified by the Length of the SIGNAL portion in step S 18 .
[0184] On the other hand, when the wireless communication apparatus 100 judges that the second decoding portion of the packet is transmitted at the transmission rate at which only the high-grade communication stations can receive the packet on the basis of the setting of the spoofed flag in the SIGNAL portion or on the basis of the provision of the SIGNAL-2 portion in step S 13 , the wireless communication apparatus 100 shifts to a high-speed transmission mode in step S 20 , and receives the MAC header portion in step S 15 . The wireless communication apparatus 100 performs the reception processing according to, for example, True Rate and True Length described in the SIGNAL-2 portion.
[0185] Now, when the wireless communication apparatus 100 can decode the reception destination address on the basis of the MAC header in step S 16 , the wireless communication apparatus 100 compares the reception destination address with the local station address in step S 17 . Then, when both the addresses coincide with each other; the wireless communication apparatus 100 performs the reception processing for the packet length specified by the Length of the SIGNAL portion in step S 18 .
[0186] Moreover, when the reception destination address and the local station address do not coincide with each other in step S 17 , the wireless communication apparatus 100 raises an NAV for the Duration determined by (packet length)/(transmission rate), and restrains its transmission in step S 19 .
[0187] Lastly, a communication operation in the wireless network according to the present embodiment is described. In the wireless network, conventional stations in conformity with the conventional IEEE 802.11b and high-grade communication stations in conformity with the IEEE 802.11g corresponding to a high-speed edition standard using the same band as that of the IEEE 802.11b intermixedly operates.
[0188] FIG. 8 shows a communication operation example based on CSMA/CA. In the shown example, there are four communication stations #0 to #3 in a communication environment. Among them, the communication station #0 and the communication station #2 are supposed to be high-grade communication stations, and the communication station #2 and the communication station #3 are supposed to be conventional stations.
[0189] Each communication station having transmission data monitors a medium state for a predetermined inter frame space DIFS from the last detection of a packet. When any media are clear, namely when there are no transmission signals, the communication station performs random backoff. Furthermore, when there are no transmission signals also in this period, a transmission right is given to the communication station. In the shown example, the communication station #0 setting the random backoff shorter than that of the other peripheral stations acquires the transmission right, and can start a data transmission to the communication station #1 similarly as a high-grade communication station.
[0190] At the time of the data transmission, the transmission source communication station #0 transmits a first decoding portion corresponding to the PHY header according to a first communication method, which all communication stations can receive, and transmits a second decoding portion corresponding to the MAC frame according to a second communication method, which only the high-grade communication stations can receive. Then, the transmission source communication station #0 performs the spoofing of the information of the transmission rate (Rate) and the packet length (Length) in the SIGNAL portion of the PHY header in order that the value of (packet length)/(rate) may be equal to the duration until an ACK packet for which communications are desired to be stopped.
[0191] Alternatively, the transmission source communication station #0 transmits the SIGNAL portion in the PHY header according to the first communication method, which all communication stations can receive, and successively transmits the SIGNAL-2 portion modulated according to a modulation system, which each high-grade communication station knows but the first communication stations do not know. After that, the transmission source communication station #0 transmits the second decoding portion corresponding to the MAC frame according to the second communication method, which only the high-grade communication stations can receive. Then, the transmission source communication station #0 performs the spoofing of the information of the transmission rate (Rate) and the packet length (Length) in the SIGNAL portion of the PHY header in order that the value of (packet length)/(rate) may equal to the duration until the ACK packet for which communications are desired to be stopped.
[0192] The communication station #2 and the communication station #3 as the conventional stations can hear the SIGNAL portion of the packet from the communication station #0, and set a packet length and a transmission rate different from the actual state to perform reception for a period of time corresponding to the duration until the transmission of the ACK packet ends. The data packet from the communication station #0 is not transmitted for a period of (packet length)/(rate), but the communication station #2 and the communication station #3 try to receive the data packet and do not start any transmissions. As a result, the communication stations #2 and #3 restrain their transmissions. Moreover, because the rate and the packet length are different from the real transmission of the packet, the rate and the packet cannot be normally decoded, and the communication station #2 and the communication station #3 destroy the packet.
[0193] Moreover, in the reserved area (Reserve) of the SIGNAL portion, a spoofed flag indicating the spoofing of the information of the transmission rate (Rate) and the packet length (Length) of the SIGNAL portion is set. In this case, the communication mode of a MAC frame, i.e. the true transmission rate (True Rate) and the true packet length (True Length), is indicated by a combination of Rate and Length. Alternatively, by providing the SIGNAL-2 portion, the spoofing of the information of the transmission rate (Rate) and the packet length (Length) of the SIGNAL portion is indicated, and the true transmission rate (True Rate) and the true packet length (True Length) of the MAC frame are described.
[0194] The communication station #1 being the communication party is a high-grade communication station, and detects the spoofing of the information of a packet length and a rate of a SIGNAL portion on the basis of the spoofed flag. Alternatively, the communication station #1 detects the spoofing of the information of the packet length and the rate of a SIGNAL portion on the basis of the success of the decoding of the SIGNAL-2 portion. Then, the communication station #1 destroys the reception result of the SIGNAL portion in response to the detection of the spoofing. Furthermore, the communication station #1 receives the MAC frame as the successive second decoding portion at the transmission rate indicated by the SIGNAL portion or the SIGNAL-2 portion, and performs the reception operation of the data addressed to the local station for the duration of Duration described in the MAC header. Then, when the data reception is completed, the communication station #1 returns an ACK packet to the data transmission source communication station #0.
[0195] In such a way, according to the CSMA/CA system, contention is avoided while a single communication station acquires a transmission right, and any collisions can be avoided by the stop of peripheral stations' data transmission operations during a data communication operation. Moreover, in case of inexistence of the concealed terminal problem, peripheral stations can raise NAV's to avoid collisions without passing through the RTS/CTS procedure as shown in the drawings. Thereby, overhead can be reduced.
[0196] FIG. 9 shows a communication operation example based on RTS/CTS. In the shown example, there are four communication stations #0 to #3 in a communication environment. Among them, the communication station #0 and the communication station #2 are supposed to be high-grade communication stations, and the communication station #2 and the communication station #3 are supposed to be conventional stations.
[0197] Each communication station is in the following communication state. That is, the communication station #2 can communicate with the adjacent communication station #0, and the communication station #0 can communicate with the adjacent communication stations #1 and #2. The communication station #1 can communicate with the adjacent communication stations #0 and #3. The communication station #3 can communicate with the adjacent communication station #1. Furthermore, the communication station #2 is a concealed terminal for the communication station #1, and the communication station #3 is a concealed terminal for the communication station #0.
[0198] Each communication station having transmission data monitors a medium state for a predetermined inter frame space DIFS from the last detection of a packet. When any media are clear, namely when there are no transmission signals, the communication station performs random backoff. Furthermore, when there are no transmission signals also in this period, a transmission right is given to the communication station. In the shown example, the communication station #0 setting the random backoff shorter than that of the other peripheral stations acquires the transmission right, and can start a data transmission to the communication station #1 similarly as a high-grade communication station after the inter frame space DIFS.
[0199] That is, the data transmitting communication station #0 transmits a transmission request packet (RTS) to the communication station #1. To this transmission, the reception destination communication station #1 returns a confirmation note (CTS) to the communication station #0 after the shorter inter frame space SIFS (Short IFS).
[0200] Now, at the time of an RTS packet, the communication station #0 transmits a first decoding portion corresponding to the PHY header according to a first communication method, which all communication stations can receive, and transmits a second decoding portion corresponding to the MAC frame according to a second communication method, which only the high-grade communication stations can receive. Then, the transmission source communication station #0 performs the spoofing of the information of the transmission rate (Rate) and the packet length (Length) in the SIGNAL portion of the PHY header in order that the value of (packet length)/(rate) may be equal to the duration until an ACK packet for which communications are desired to be stopped.
[0201] Alternatively, the transmission source communication station #0 transmits the SIGNAL portion in the PHY header according to the first communication method, which all communication stations can receive, and successively transmits the SIGNAL-2 portion modulated according to a modulation system, which each high-grade communication station knows but the first communication stations do not know. After that, the communication station #0 transmits the second decoding portion corresponding to the MAC frame according to the second communication method, which only the high-grade communication stations can receive. Then, the communication station #0 performs the spoofing of the information of the transmission rate (Rate) and the packet length (Length) in the SIGNAL portion of the PHY header in order that the value of (packet length)/(rate) may equal to the duration until the ACK packet for which communications are desired to be stopped.
[0202] The communication station #2 as a conventional station can hear the SIGNAL portion of the RTS packet from the communication station #0, and set a packet length and a transmission rate different from the actual state to perform a reception operation for a period of time corresponding to (packet length)/(rate). The RTS packet from the communication station #0 is not transmitted for a period of (packet length)/(rate), but the communication station #2 tries to receive the data packet and do not start any transmissions. As a result, the communication station #2 restrains its transmission until the transmission of the ACK packet is completed. Moreover, because the rate and the packet length are different from the real transmission of the packet, the rate and the packet cannot be normally decoded, and the communication station #2 destroys the packet to transmitted according to the second communication method after that.
[0203] Moreover, the reception destination communication station #1 transmits the first decoding portion corresponding to the PHY header according to the first communication method, which all communication station can receive, at the time of a transmission of a CTS packet, and transmits the second decoding portion corresponding to the MAC frame according to the second communication method, which only the high-grade communication stations can receive. Then, the communication station #1 performs the spoofing of the information of the transmission rate (Rate) and the packet length (Length) in the SIGNAL portion of the PHY header in order that the value of (packet length)/(rate) may be equal to the duration until the ACK packet for which communications are desired to be stopped.
[0204] Alternatively, the reception destination communication station #1 transmits the SIGNAL portion in the PHY header according to the first communication method, which all communication stations can receive, and successively transmits the SIGNAL-2 portion modulated according to a modulation system which each high-grade communication station knows but the first communication stations do not know. After that, the reception destination communication station #1 transmits the second decoding portion corresponding to the MAC frame according to the second communication method, which only the high-grade communication stations can receive. Then, the reception destination communication station #1 performs the spoofing of the information of the transmission rate (Rate) and the packet length (Length) in the SIGNAL portion of the PHY header in order that the value of (packet length)/(rate) may equal to the duration until the ACK packet for which communications are desired to be stopped.
[0205] The communication station #3 as the conventional station can hear the SIGNAL portion of the CTS packet from the communication station #1, and sets a packet length and a transmission rate different from the actual state to perform reception for a period of time corresponding to the duration until the transmission of the ACK packet ends. The CTS packet from the communication station #1 is not transmitted for a period of (packet length)/(rate), but the communication station #3 tries to receive the CTS packet and do not start any transmissions. As a result, the communication station #3 restrains its transmission until the completion of the transmission of the ACK packet. Moreover, because the rate and the packet length are different from the real transmission of the packet, the rate and the packet length cannot be normally decoded, and the communication station #3 destroy the packet to be transmitted after that according to the second communication method.
[0206] Then the communication station #0 starts the transmission of a data packet in response to the reception of the CTS packet after the inter frame space SIFS.
[0207] At the data transmission, the transmission source communication station #0 transmits the first decoding portion corresponding to the PHY header according to the first communication method, which all communication stations can receive, and also transmits the second decoding portion corresponding to the MAC frame according to the second communication method, which only the high-grade communication stations can receive. Then, the transmission source communication station #0 performs the spoofing of the information of the transmission rate (Rate) and the packet length (Length) in the SIGNAL portion of the PHY header, and sets a spoofed flag indicating the spoofing.
[0208] Alternatively, the transmission source communication station #0 transmits the SIGNAL portion in the PHY header according to the first communication method, which all communication stations can receive, and successively transmits the SIGNAL-2 portion modulated according to a modulation system, which each high-grade communication station knows but the first communication stations do not know. After that, the transmission source communication station #0 transmits the second decoding portion corresponding to the MAC frame according to the second communication method, which only the high-grade communication stations can receive. Then, the transmission source communication station #0 performs the spoofing of the information of the transmission rate (Rate) and the packet length (Length) in the SIGNAL portion of the PHY header in order that the value of (packet length)/(rate) may equal to the duration until the ACK packet for which communications are desired to be stopped.
[0209] The communication station #1 detects the spoofing of the information of a packet length and a rate of a SIGNAL portion on the basis of the spoofed flag. Alternatively, the communication station #1 detects the spoofing of the information of the packet length and the rate of the SIGNAL portion on the basis of the success of the decoding of a SIGNAL-2 portion. Then, the communication station #1 destroys the reception result of the SIGNAL portion in response to the detection of the spoofing. Furthermore, the communication station #1 receives the MAC frame as the successive second decoding portion at the transmission rate indicated by the SIGNAL portion or the SIGNAL-2 portion, and performs the reception operation of the data addressed to the local station for the duration of Duration described in the MAC header. Then, when the reception of the data packet from the communication station #0 is completed, the communication station #1 returns an ACK packet to the data transmission source communication station #0 after the inter frame space SIFS.
[0210] As described above, when a concealed terminal receives at least one of the RTS and the CTS, the concealed terminal sets a transmission stop duration of the local station for the duration in which the data transmission based on the RTS/CTS procedure is expected to be performed, and thereby collisions can be avoided.
[0211] However, in the example shown in FIG. 9 , in the case where the duration until the end of the RTS/CTS procedure (i.e. the duration until the ACK) is specified as the Duration, peripheral stations must wait until the last even if the RTS/CTS procedure is broken on the way, communication resources are wasted.
[0212] Accordingly, also a mechanism called as a Short NAV can be considered. In the Short NAV, each packet of the RTS, the CTS and data secures only the end of the next packet as the Duration. For example, the RTS packet is secured until the end of the CTS packet; the CTS packet is secured until the end of the data packet; the data packet is secured until the end of the ACK packet severally as the Duration. Consequently, even if the RTS/CTS procedure is broken halfway, the peripheral stations are not required to wait until the last.
[0213] FIG. 10 shows a communication operation example based on the RTS/CTS using the Short NAV. Incidentally, in the shown example, a communication environment similar to one shown in FIG. 9 is supposed.
[0214] Each communication station having transmission data monitors a medium state for a predetermined inter frame space DIFS from the last detection of a packet. When any media are clear, namely when there are no transmission signals, the communication station performs random backoff. Furthermore, when there are no transmission signals also in this period, a transmission right is given to the communication station. In the shown example, after the inter frame space DIFS, the communication station #0, which has the random backoff set to be shorter than that of the other peripheral stations, acquires the transmission right to be able to start a data transmission to the communication station #1.
[0215] That is, the communication station #0, which transmits data, transmits a transmission request packet (RTS) to the communication station #1. On the other hand, the communication station #1 being the reception destination returns a confirmation note (CTS) to the communication station #0 after a shorter inter frame space Short IFS (SIFS).
[0216] Now, at the time of an RTS packet, the communication station #0 transmits a first decoding portion corresponding to the PHY header according to a first communication method, which all communication stations can receive, and transmits a second decoding portion corresponding to the MAC frame according to a second communication method, which only the high-grade communication stations can receive. Then, the transmission source communication station #0 performs the spoofing of the information of the transmission rate (Rate) and the packet length (Length) in the SIGNAL portion of the PHY header in order that the value of (packet length)/(rate) may be equal to the duration until an CTS packet.
[0217] Alternatively, the transmission source communication station #0 transmits the SIGNAL portion in the PHY header according to the first communication method, which all communication stations can receive, and successively transmits the SIGNAL-2 portion modulated according to a modulation system, which each high-grade communication station knows but the first communication stations do not know. After that, the communication station #0 transmits the second decoding portion corresponding to the MAC frame according to the second communication method, which only the high-grade communication stations can receive. Then, the communication station #0 performs the spoofing of the information of the transmission rate (Rate) and the packet length (Length) in the SIGNAL portion of the PHY header in order that the value of (packet length)/(rate) may equal to the duration for which communications are desired to be stopped.
[0218] The communication station #2 as a conventional station can hear the SIGNAL portion of the RTS packet from the communication station #0, and set a packet length and a transmission rate different from the actual state to perform a reception operation for a period of time corresponding to (packet length)/(rate). The RTS packet from the communication station #0 is not transmitted for a period of (packet length)/(rate), but the communication station #2 tries to receive the data packet and do not start any transmissions. As a result, the communication station #2 restrains its transmission until the transmission of the CTS packet is completed. Moreover, because the rate and the packet length are different from the real transmission of the packet, the rate and the packet cannot be normally decoded, and the communication station #2 destroys the packet to transmitted according to the second communication method after that.
[0219] Moreover, the reception destination communication station #1 transmits the first decoding portion corresponding to the PHY header according to the first communication method, which all communication station can receive, at the time of a transmission of a CTS packet, and transmits the second decoding portion corresponding to the MAC frame according to the second communication method, which only the high-grade communication stations can receive. Then, the communication station #1 performs the spoofing of the information of the transmission rate (Rate) and the packet length (Length) in the SIGNAL portion of the PHY header in order that the value of (packet length)/(rate) may be equal to the duration until the data packet.
[0220] Alternatively, the reception destination communication station #1 transmits the SIGNAL portion in the PHY header according to the first communication method, which all communication stations can receive, and successively transmits the SIGNAL-2 portion modulated according to a modulation system which each high-grade communication station knows but the first communication stations do not know. After that, the reception destination communication station #1 transmits the second decoding portion corresponding to the MAC frame according to the second communication method, which only the high-grade communication stations can receive. Then, the reception destination communication station #1 performs the spoofing of the information of the transmission rate (Rate) and the packet length (Length) in the SIGNAL portion of the PHY header in order that the value of (packet length)/(rate) may equal to the duration until the data packet for which communications are desired to be stopped.
[0221] The communication station #3 as the conventional station can hear the SIGNAL portion of the CTS packet from the communication station #1, and sets a packet length and a transmission rate different from the actual state to perform reception for a period of time corresponding to (packet length)/(rate). The CTS packet from the communication station #1 is not transmitted for a period of (packet length)/(rate), but the communication station #3 tries to receive the CTS packet and do not start any transmissions. As a result, the communication station #3 restrains its transmission until the completion of the transmission of the data packet. Moreover, because the rate and the packet length are different from the real transmission of the packet, the rate and the packet length cannot be normally decoded, and the communication station #3 destroy the packet to be transmitted after that according to the second communication method.
[0222] Then the communication station #0 starts the transmission of a data packet in response to the reception of the CTS packet after the inter frame space SIFS.
[0223] At the data transmission, the transmission source communication station #0 transmits the first decoding portion corresponding to the PHY header according to the first communication method, which all communication stations can receive, and also transmits the second decoding portion corresponding to the MAC frame according to the second communication method, which only the high-grade communication stations can receive. Then, the transmission source communication station #0 performs the spoofing of the information of the transmission rate (Rate) and the packet length (Length) in the SIGNAL portion of the PHY header in order that the value of (packet length)/(rate) may be equal to the duration of Duration until the ACK packet, and sets a spoofed flag indicating the spoofing.
[0224] Alternatively, the transmission source communication station #0 transmits the SIGNAL portion in the PHY header according to the first communication method, which all communication stations can receive, and successively transmits the SIGNAL-2 portion modulated according to a modulation system, which each high-grade communication station knows but the first communication stations do not know. After that, the transmission source communication station #0 transmits the second decoding portion corresponding to the MAC frame according to the second communication method, which only the high-grade communication stations can receive. Then, the transmission source communication station #0 performs the spoofing of the information of the transmission rate (Rate) and the packet length (Length) in the SIGNAL portion of the PHY header in order that the value of (packet length)/(rate) may equal to the duration until the ACK packet for which communications are desired to be stopped.
[0225] The communication station #2 as a conventional station can hear the SIGNAL portion of the RTS packet from the communication station #0, and set a packet length and a transmission rate different from the actual state to perform a reception operation for a period of time corresponding to (packet length)/(rate). The data packet from the communication station #0 is not transmitted for a period of (packet length)/(rate), but the communication station #2 tries to receive the data packet and do not start any transmissions. As a result, the communication station #2 restrains its transmission until the transmission of the ACK packet is completed. Moreover, because the rate and the packet length are different from the real transmission of the packet, the rate and the packet cannot be normally decoded, and the communication station #2 destroys the packet to transmitted according to the second communication method after that.
[0226] When the communication station #1 detects the spoofing of the information of the packet length and the rate of a SIGNAL portion on the basis of the spoofed flag, the communication station #1 destroys the information. Furthermore, the communication station #1 receives the MAC frame as the successive second decoding portion at the corresponding transmission rate, and performs the reception operation of the data addressed to the local station for the duration of Duration described in the MAC header. Then, when the reception of the data packet from the communication station #0 is completed, the communication station #1 returns an ACK packet to the data transmission source communication station #0 after the inter frame space SIFS.
[0227] As described above, when a concealed terminal receives at least one of the RTS and the CTS, the concealed terminal sets a transmission stop duration of the local station for the duration in which the transmission of the next packet is expected to be completed, and thereby collisions can be avoided.
[0228] As described above, in the present embodiment, the high-grade communication stations perform the spoofing of the description of the SIGNAL portion of the PHY header, and provide the transmission stop duration to the conventional stations until a transaction according to the high-grade communication method ends to obtain compatibility. That is, the conventional stations unable to deal with the high-grade communication method stop their transmissions for the duration in which the transmission of the next packet is expected to end, and thereby collisions can be avoided.
[0229] In the examples shown in FIGS. 8 and 9 , in a communication procedure executed according to the second communication method, the spoofing of the description of the SIGNAL portion is performed in order that the conventional stations may stop their transmission operations for the duration until the ACK transmission ends. Moreover, when a packet transmission is performed according to a communication procedure to perform multiple connections with a plurality of communication stations in the MAC frame according to the second communication system, the ACK (response packet) transmission is performed in a time division multiplex from each remote station. Also in this case, the above-mentioned mechanism can be applied. Moreover, the transmission of the ACK packet hereupon is not limited to the case of single ACK packet, but includes, for example, the case where the ACK packet is multiplexed with other kinds of packets such as an RTS packet, a CTS packet and data packet to be transmitted.
[0230] FIG. 17 shows communication operation sequencing in which a plurality of reception stations replies by a response packet in time division to a transmission packet from a transmission station.
[0231] A packet #0 transmitted from the communication station #0 is supposed to request a reply from the communication station #1 and the communication station #2 severally. The packet #0 notifies the communication station #1 and the communication station #2 of the timing of the transmissions of their response packets lest the response packets should collide.
[0232] At this time, the value of (packet length)/(rate) of the SIGNAL portion of the packet #0 is set to be the time when the receptions of all response packets have been completed. Thereby, it is prevented that the communication station #3 locating at a position distant from the communication station #1 and communication station #2 to the degree of unable to receiving the response packets from the communication stations #1 and #2 disturbs the responses. Because the SIGNAL portion is transmitted at the lowest rate, such setting is effective to eliminate such a concealed terminal.
[0233] Incidentally, Japanese Patent Application No. 2003-297919, which has been assigned to the present applicant already, discloses a communication system in which a transmission station transmits a data frame addressed to a plurality of reception stations in the space division multiple access (SDMA) and each reception station reply by ACK in the time division multiplex.
[0234] In the above, specific embodiments have been referred to while the present invention has been described in detail. However, it is clear that the person skilled in the art can modify and substitute the embodiments without departing from the scope and sprit of the present invention. That is, the present invention has been disclosed in the form of exemplifying, and the contents of the description of the present specification should not be interpreted limitedly. For the judgment of the subject matter of the present invention, claims should be considered.
[0235] This application claims priority from Japanese Priority Document No. 2004-196837, filed on Jul. 2, 2004 with the Japanese Patent Office, which document is hereby incorporated by reference. | Random access operation is performed under a communication environment in which a plurality of communication modes having different transmission rate coexist with small overhead. A high-grade communication station spoofs information of a packet length and a rate in a decoding portion so that a value of (packet length)/(rate) corresponds to a duration where the communication is hoped to be stopped. The other station receiving the spoofed information receives the rest of the packet with the designated rate during the interval designated by the value of (packet length)/(rate). In this case, the packet length and the rate are not those of actually transmitted packet so that this packet is discarded. | 7 |
TECHNICAL FIELD
The disclosed invention relates generally to an airbag system for a vehicle. More particularly, the disclosed invention relates to a tether venting system for an airbag module that reduces package space by incorporating a plurality of hinged vents.
BACKGROUND OF THE INVENTION
Automotive vehicles incorporate a variety of restraint systems to provide for the safety of occupants. These systems are generally included to reduce the likelihood of injury to the occupants in a crash event, Common safety systems include front airbags, side airbags, and seatbelts. The airbags are deployed within a vehicle and expand within the passenger compartment in a crash event to serve as a cushion between the occupant and interior vehicle components such as the steering wheel, the instrument panel and the windshield.
One of the more difficult challenges for manufacturers of airbags is in the design of a system that properly responds to the out-of-position (“OOP”) occupant, and particularly to the occupant positioned close to the airbag. As a result, the same amount of airbag-expanding gas is released by the inflator without accounting for the position of the vehicle occupant, this in spite of the fact that the out-of-position occupant may not require the same level of deployment energy as compared to the in-position occupant.
In response to this challenge some manufacturers have turned to the use of a tethered vent system in which a vent door is provided and is opened during initial pressurization of the airbag. The vent door is typically situated in the airbag housing and is attached to the housing by a living hinge. The vent door is open only temporarily and closes at a later stage in the airbag deployment event by a tether attached at one end to the vent door and at the other end to the primary surface of the airbag cushion. As the airbag cushion deploys vehicle-rearward, it pulls the tether and the tether pulls the vent door closed.
While this arrangement has proven largely effective, it suffers from size limitations, particularly when the airbag is positioned in the steering wheel. Specifically, there is a limited amount of package space between the driver's-side airbag and the steering wheel.
It would be desirable to have an airbag venting system that is effective in gas ventilation but which occupies less package space than used in known arrangements.
SUMMARY OF THE INVENTION
The disclosed invention provides an airbag module for use in an automotive vehicle which includes an airbag housing and an airbag attached to the airbag housing. The airbag housing has a vent area. A pair of vent doors is attached to the airbag housing, although more than two vent doors may be used. Each of the pair of doors is attached to the airbag housing by a hinge such as is known in the art. The doors are provided adjacent one another such that their free ends are generally located side-by-side. The doors may be of equal widths or may be of different widths. A tether arrangement is provided between the vent doors and the airbag.
The tether arrangement may include a first tether portion connected to one of the vent doors, a second tether portion connected to the other vent door, and a common tether connecting the first tether portion and the second tether portion to the airbag. As an alternative, the tether arrangement may include an airbag connecting end and a vent door connecting end. One of the vent doors has a tether-passing hole. The airbag connecting end is connected to the airbag. The vent door connecting end is passed through the tether-passing hole of one door and is connected to the other door. In an additional embodiment, the tether arrangement includes one tether connecting one of the doors to the airbag and another tether connecting the other of the doors to the airbag.
Other features of the invention will become apparent when viewed in light of the detailed description of the preferred embodiment when taken in conjunction with the attached drawings and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of this invention, reference should now be made to the embodiment illustrated in greater detail in the accompanying drawings and described below by way of examples of the invention wherein:
FIG. 1 illustrates a sectional view of a portion of an airbag module including a vent arrangement according to the first embodiment of the invention;
FIG. 2 illustrates a sectional view of a portion of an airbag module including a vent arrangement according to the second embodiment of the invention; and
FIG. 3 illustrates a sectional view of a portion of an airbag module including a vent arrangement according to the third embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In the following figures, the same reference numerals will be used to refer to the same components. In the following description, various operating parameters and components are described for one constructed embodiment. These specific parameters and components are included as examples and are not meant to be limiting.
Referring to FIG. 1 , there is shown a sectional view of an occupant protection device, generally illustrated as 10 . The device 10 includes an inflatable protection component embodied in the structure of an airbag 12 . The inflatable protection component may be an airbag as shown or may be another inflatable safety device. Regardless of the configuration, the airbag 12 is composed of a variety of woven or non-woven materials, including nylon or a polymerized material.
The airbag 12 includes a pair of opposed, spaced apart side panels 14 and 14 ′ and an outer panel 16 . The airbag 12 also includes a bottom panel 18 and a top panel (not shown). Together the side panels 14 and 14 ′, the outer panel 16 , the bottom panel 18 and the top panel define the airbag 12 . The airbag 12 is open at open end 20 .
The open end 20 is attached to an airbag base assembly 22 . The airbag base assembly 22 includes a base plate 24 that is fixedly attached to the vehicle at an appropriate location. An inflator 26 is mounted on the base plate 24 . The inflator 26 includes a housing 28 having a series of gas passages 30 formed therein in a known manner. It is to be understood that the configuration of the airbag base assembly 22 as shown is for illustrative purposes and is not intended as being limiting. Other configurations of the airbag base assembly 22 could be adapted for use with the tether and vent door arrangement disclosed herein.
As is known in the art, the non-deployed airbag 12 is in a deflated and folded state and is packed within the airbag module 10 . However, in certain events in which the vehicle is impacted, the inflator 26 is engaged. When the inflator 26 is activated, inflating gas outflows from the inflator 26 through the series of gas passages 30 . The inflating gas enters the airbag 12 . The figures illustrate the airbag in its initial inflation stages.
A vent aperture 32 is formed in the base plate 24 . The vent aperture 32 is provided to allow the exhaust of a certain amount of inflating gas out of the airbag 12 during the initial stage of inflation. By exhausting gas very early in the inflation of the airbag 12 allowance is made for the out-of-position vehicle occupant by reducing the initial force of the airbag 12 .
However, this early stage exhaustion of gas must be halted after a very short period of time. A pair of opposed vent doors 34 and 36 are provided for this purpose. The vent doors 34 and 36 are attached to the base plate 24 adjacent the vent aperture 32 . The vent doors 34 and 36 are movable between the open positions illustrated to allow for the early exhaustion of inflating gas during initial inflation of the airbag 12 . The out-passing inflating gas forces the vent doors 34 and 36 to the illustrated open positions.
A tether assembly 38 is provided to effect closure of the vent doors 34 and 36 at a predetermined stage of inflation of the airbag 12 . The tether assembly 38 includes a first tether portion 40 attached to the vent door 34 and a second tether portion 42 attached to the vent door 36 . The first tether portion 40 and the second tether portion 42 connect to an airbag tether portion 44 at a connection point 46 . The airbag tether portion 44 is connected to a point 48 on the outer panel 16 of the airbag 12 .
In operation, when an impact event occurs sufficient to activate the inflator 26 , inflating gas is introduced into the interior of the airbag 12 . The inflating gas pushes open the vent doors 34 and 36 and a portion of the gas escapes. Concurrently the airbag 12 is inflating. When a predetermined volume of gas occupies the airbag 12 the outer panel 16 of the airbag 12 is pushed away from the inflator 26 . The tether assembly 38 is pulled upon by the movement of the outer panel 16 away from the inflator 26 . As the tether assembly 38 is generally extended the first tether portion 40 pulls upon the vent door 34 and the second tether portion 42 simultaneously pulls upon the vent door 36 . The vent doors 34 and 36 continue to move toward their closed positions illustrated in broken lines in FIG. 1 until the tether assembly 28 is pulled taught and the full closure of the vent doors 34 and 36 is achieved. Closure of the vent doors 34 and 36 stops the outflow of inflating gas.
An alternate arrangement for the tether connection is illustrated in FIG. 2 in which a sectional view of an occupant protection device, generally illustrated as 50 , is shown. The device 50 includes an airbag 52 which, as in the case of the airbag 12 described above and shown in FIG. 1 , may be another inflatable protection device. The device shown is intended as being illustrative rather than limiting.
The airbag 52 includes side panels 54 and 54 ′ and an outer panel 56 . The airbag 52 further includes a bottom panel 58 and a top panel (not shown). An open end 60 is formed by the pair of side panels 54 and 54 ′, the outer panel 56 , the bottom panel 58 and the top panel.
The device 50 includes an airbag base assembly 62 to which the open end 60 of the airbag 52 is attached. The airbag base assembly 62 has a base plate 64 upon which an inflator 66 is mounted. The inflator 66 includes a housing 68 having a series of gas passages 70 .
The airbag 52 is illustrated in FIG. 2 in its partially inflated state as would be the case during initial inflation following a vehicle impact event in which some inflating gas has flowed out of the inflator 66 and into the airbag 52 . At this stage a quantity of the inflating gas is exiting the airbag 52 by way of a vent aperture 72 formed in the base plate 64 by a pair of open opposed vent doors 74 and 76 . The vent door 74 is hingedly attached to a position adjacent the vent aperture 72 . The vent door 76 is hingedly attached to a position adjacent the vent aperture 72 . The vent doors 74 and 76 are movable between the illustrated open positions in which inflating gas is allowed to pass and a closed position (illustrated by broken lines) in FIG. 2 .
After a quantity of gas has been allowed to flow out of the expanding airbag 52 the vent doors 74 and 76 are moved to their closed positions. A tether arrangement is provided for closure of the vent doors 74 and 76 . Provision for the tether arrangement is made in part by a tether-passing aperture 78 that is formed through the vent door 74 . (The tether passing aperture could be formed as well through the vent door 76 instead of the vent door 74 . The arrangement shown is for illustrative purposes.)
A tether 80 is provided and includes a door attachment end 82 and an airbag attachment end 84 . The airbag attachment end 84 is attached to a point on the inside of the airbag 12 . The door attachment end 82 of the tether 80 is attached to the vent door 76 . The tether 80 passes through the tether-passing aperture 78 . A movement-halting bead 86 is attached to a portion of the tether 80 at a point between the tether-passing aperture 78 and the airbag attachment end 84 . The movement-halting bead 86 is provided to minimize the amount of tether 80 that can pass through the tether-passing aperture 78 . By controlling the amount of tether 80 that is allowed beyond the point of the tether-passing aperture 78 tangling of the tether 80 is prevented.
In operation, when an impact event occurs sufficient to activate the inflator 66 , inflating gas is introduced into the airbag 52 . Some of the inflating gas pushes the vent doors 74 and 76 to the open positions illustrated in FIG. 2 . The vent doors 74 and 76 are permitted to swing open freely. Only a certain length of the tether 80 will be permitted to pass through the tether-passing aperture 78 as limited by the movement-halting bead 86 . The airbag 52 continues to inflate and when a predetermined volume of gas occupies the airbag 52 the outer panel 56 of the airbag 52 is pushed away from the area of the inflator 66 . The tether 80 is pulled by movement of the outer panel 56 and, as it is pulled, a portion and as it is pulled the a portion of the tether 80 passes through the tether-passing aperture 78 while the door attachment end 82 of the tether 80 pulls upon the vent door 76 . Both the vent door 74 and the vent door 76 are moved to their closed positions as the tether 80 is pulled taught between the airbag attachment end 84 and the door attachment end 82 . Venting of the airbag 52 is halted upon closure of the vent door 74 and the vent door 76 .
An additional arrangement for the tether connection provided herein is illustrated in FIG. 3 . With reference to that figure, an occupant protection device, generally illustrated as 100 , is shown. The occupant protection device 100 includes an airbag 102 . As set forth above with respect to both FIG. 1 and FIG. 2 , the airbag 102 may be another inflatable occupant protection device.
The airbag 102 includes side panels 104 and 104 ′ and an outer panel 106 . The airbag 102 further includes a bottom panel 108 and a top panel that is not shown. An open end 110 is defined by the pair of side panels 104 and 104 ′, the outer panel 106 , the bottom panel 108 and the top panel.
The occupant protection device 100 includes an airbag base assembly 112 . The open end 110 of the airbag 102 is attached to the airbag base assembly 112 . The airbag base assembly 112 includes a base plate 114 . An inflator 116 is mounted to the base plate 114 . As set forth with respect to inflator discussed above with respect to the embodiments of the invention shown in FIG. 1 and FIG. 2 , the inflator 116 includes a housing 118 having a series of gas passages 120 . A vent aperture 122 is formed in the base plate 114 .
The airbag 102 shown in FIG. 3 is illustrated in its partially inflated state shortly after initial inflation by the inflator 116 . Some of the inflating gas is shown escaping through the vent aperture 122 . A pair of vent doors is provided to control the escape of the inflating gas. The pair of vent doors includes a first vent door 124 and a second vent door 126 . As illustrated, the width of the first vent door 124 is less than the width of the second vent door 126 . However, the width of the first vent door 124 could be greater than the width of the second vent door 126 . The configuration shown is for illustrative purposes only. The first vent door 124 and the second vent door 126 are hingedly attached to the area adjacent the vent aperture 122 . The first vent door 124 and the second vent door 126 are both movable between the illustrated open positions and closed positions shown in broken lines in FIG. 3 . A first vent door tether 128 is connected at one end to the first vent door 124 and at the other end to the airbag 102 . A second vent door tether 130 is connected at one end to the second vent door 126 and at the other end to the airbag 102 .
A quantity of inflating gas is allowed to escape through the vent aperture 122 as discussed above upon initial inflation. However, after the quantity of gas has been allowed to flow out of the expanding airbag 102 the passage of gas is halted by movement of the vent doors 124 and 126 to their closed positions illustrated by the broken lines, Closure of the vent doors 124 and 126 is achieved by movement of the outer panel 106 of the airbag 102 in a direction essentially away from the inflator 116 . As the first door vent tether 128 is pulled taught the first vent door 124 is moved from the illustrated open position to the closed position shown in broken lines. Similarly, as the second door vent tether 130 is pulled taught the second vent door 126 is moved from the illustrated open position to the closed position shown in broken lines. Passage of inflating gas is halted by closure of the first vent door 124 and the second vent door 126 .
The arrangement of the occupant protection device 100 illustrated in FIG. 3 and explained in conjunction therewith also provides a variation of the size of the vent aperture 122 over time. Specifically, the first vent door tether 128 and the second vent door tether 130 may be of different lengths, providing for the closure of one or the other of the vent doors 124 and 126 before the other of the vent doors 126 and 124 upon inflation of the airbag 102 .
The foregoing discussion discloses and describes an exemplary embodiment of the present invention. One skilled in the art will readily recognize from such discussion, and from the accompanying drawings and claims that various changes, modifications and variations can be made therein without departing from the true spirit and fair scope of the invention as defined by the following claims. | A system and method for venting an airbag is provided. The system includes a set of vent doors, thereby reducing the overall package spaced that would otherwise be required to allow the doors to swing open. The vent doors are connected by a single tether or by multiple tethers to the primary surface of the airbag cushion. | 1 |
This application is a division of application Ser. No. 08/105,718, filed Aug. 12, 1993 now U.S. Pat. No. 5,416,249.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to apparatus and a method for encapsuling drums containing hazardous waste so that the drums may be stored and transported without danger to those in the vicinity of the drums. The hazardous waste may be radioactive.
2. Description of the Prior Art
With the advent of modern environmental laws and the realization that hazardous wastes can cause severe damage to the environment and those exposed to the hazardous waste, many methods have been proposed to treat, transport and store hazardous wastes to render them safe. Hazardous waste containers have been developed to store smaller quantities of hazardous waste. An example of such a container is disclosed in U.S. Pat. No. 4,708,258.
Until now, no apparatus and no method have been proposed for safely transporting and storing hazardous waste material that is already stored in metal drums which may be deteriorating as a result of age or the corrosive action of the hazardous material itself.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided apparatus for encapsuling a cylindrical drum containing hazardous waste material for subsequent transportation and storage of the drum. An overcapsule having a cylindrical wall longer than the overall length of the drum and having an inside diameter greater than the outside diameter of the drum with a closed end wall is provided. The overcapsule has spacers abutting the drum outer surface when the overcapsule is positioned over the drum to maintain a uniform annular space between the cylindrical drum and the inner cylindrical surface of the overcapsule. A seal formed on the open end of the overcapsule cooperates with the cylindrical drum to form a sealed annular space around the drum and a sealed cylindrical space above the drum. Encapsulation grout fills the sealed annular space around the drum and the sealed cylindrical space above the drum. An undercapsule is formed to receive the end of the overcapsule with the cylindrical drum grouted within the overcapsule to enclose the bottom the drum and the end of the overcapsule. Encapsulation grout is provided to fill all the spaces between the bottom of the drum and the undercapsule and between the overcapsule and the undercapsule.
Further in accordance with the present invention, there is provided a method of encapsuling a cylindrical drum containing hazardous waste material for subsequent transportation and storage of the drum. The method includes placing an inverted overcapsule over the drum to enclose the top and the entire cylindrical wall of the drum with the walls of the overcapsule being spaced apart from the top and the cylindrical wall of the drum. The space between the bottom of the drum cylindrical wall and the bottom of the overcapsule cylindrical wall is sealed. An encapsulation grout is injected into the space between the cylindrical drum and the overcapsule and the encapsulation grout hardens to form a dense shell around the cylindrical drum. An injection port is formed through the lower portion of the overcapsule, through the hardened encapsulation grout and through the drum and thereafter a solidification grout is injected through the port to solidify and stabilize the hazardous waste material within the drum. The overcapsule and the drum are then placed onto an undercapsule and encapsulation grout is utilized to seal the overcapsule and the undercapsule together to join them and to seal the injection port.
Accordingly, a principal object of the present invention is to provide apparatus for encapsuling hazardous wastes that are stored in drums.
Another object of the present invention is to provide a method of encapsuling hazardous waste stored in drums.
Another object of the present invention is to provide safe transportation and storage of hazardous wastes.
These and other objects of the present invention will be more completely disclosed and described in the following specification, the accompanying drawings and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of the capsule of the present invention in relation to a cylindrical drum containing hazardous wastes.
FIG. 2 is a sectional view showing the overcapsule of the present invention in position over the hazardous waste drum before any grout is introduced.
FIG. 3 is a sectional view similar to FIG. 2 showing the overcapsule and drum with encapsulation grout between them.
FIG. 4 is a sectional view similar to FIGS. 2 and 3 showing the overcapsule and the drum with encapsulation grout between them and with solidification grout introduced into the drum.
FIG. 5 is a sectional view similar to FIG. 4 with the undercapsule in place below the overcapsule and the drum of hazardous waste.
FIG. 6 is a sectional view taken along line VI--VI of FIG. 5.
FIG. 7 is a bottom plan view as viewed from line VII--VII of FIG. 5.
FIG. 8 is an enlarged detail of the circled portion of FIG. 5.
FIG. 9 is a perspective view of the assembled capsule of the present invention.
FIG. 10 is a perspective view similar to FIG. 9 with a portion cutaway to illustrate the interior of the capsule and drum.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, there is shown a drum 10 containing hazardous waste material. As illustrated in FIG. 1, the drum 10 is in a deteriorated condition which may permit leakage from the drum. It has been found that throughout the world, many hazardous waste materials have been stored in 55 gallon drums which are now beginning to deteriorate and leak and cause problems with retaining the hazardous waste material.
The waste products from many nuclear processing plants have been stored in 55 gallon drums and simply stacked in large warehouses. As part of the nuclear cleanup, it is now necessary to transport and safely store the hazardous waste materials which, in many instances, are radioactive.
The present invention is directed to safely encapsuling cylindrical drums containing hazardous material, which may be radioactive, in order to transport and thereafter store the material. Because some of the hazardous waste may be so dangerous that humans cannot work in the vicinity of the waste without impairing their health, some of the hazardous waste cleanup must be accomplished by robotic equipment that is remotely controlled at a safe distance from the actual work site. The present invention is directed to apparatus and a method for encapsuling hazardous waste material in a cylindrical drum that is readily adaptable to use with remote controlled robotic equipment.
As best seen in FIG. 1, the apparatus of the present invention includes an overcapsule 12 and an undercapsule 14. The overcapsule 12 has a cylindrical wall 16 and a flat end wall 18. The end wall 18 has a circular recess 20 with a lifting bar 22 positioned across the recess and with the ends of the lifting bar extending into the internal portion of the overcapsule 12 as may be seen in FIGS. 2-5 and 10.
In some applications, it may be useful to provide vent tubes 24 within the overcapsule 12. The vent tubes are designed to puncture the drum 10 when the overcapsule is positioned over the drum 10 so that gases that may be contained within the drum 10 can be released.
Spaced at 120 degree intervals around the interior cylindrical surface of the overcapsule 12 are deformable spacers 26 which position the overcapsule 12 around the drum 10 so as to form a uniform annular space between them.
A deformable annular seal 28 is secured to the bottom of the overcapsule cylindrical wall 16 by a seal ring 30 as is most clearly shown in FIG. 8. The annular seal 28 abuts the bottom of the cylindrical wall of drum 10 so as to seal the space between the drum 10 and the overcapsule 12.
A port 32 (FIGS. 1, 9, 10) is formed within the overcapsule 12 to permit encapsulation grout 34 to be pumped into the space between the overcapsule 12 and the drum 10.
As shown in FIG. 2, the overcapsule 12 is first positioned over the drum 10 so that the spacers 26 within overcapsule 12 contact the cylindrical wall of drum 10 and space the overcapsule 12 relative to the drum 10 so that there is a uniform annular space between them. As shown in FIG. 3, encapsulation grout 34 is pumped into the space between the drum 10 and the overcapsule 12 to harden and thereby entrap the drum 10 within the overcapsule 12. After the encapsulation grout 34 hardens, a port 36 (FIG. 4) is formed near the bottom of the overcapsule 12 through the overcapsule wall, through the encapsulation grout 34 and through the wall of the drum 10. In some instances, a solidification grout 38 is then pumped into the interior of drum 10 through port 36 to solidify and stabilize the waste material within drum 10. It will be appreciated that some hazardous waste material will not require solidification by means of injecting solidification grout into it, whereas other types of hazardous waste material will require such solidification and stabilization.
After the solidification grout 38 has hardened within the drum 10, as shown in FIG. 4, the overcapsule and the grouted drum 10 within the overcapsule may be lifted by attaching a crane or robotic equipment to lifting bar 22 which has now been solidly grouted by encapsulation grout 34 so that the undercapsule 14 may be positioned under them. The generally cylindrical undercapsule 14 has support rails 40 (FIG. 1) upon which the drum 10 and the overcapsule 16 are supported. The undercapsule 14 also has fork lift tunnels 42 spaced apart from each other (FIG. 5) which permit the forks of a fork lift truck to be positioned within them to lift the encapsuled drum at a later time. The undercapsule 14 also has a bottom flange 44 extending around its periphery (FIGS. 5 and 10) and the interior diameter of the bottom flange 44 is such that it can be stacked over the overcapsule 12 of another encapsuled drum.
Before the grouted overcapsule of FIG. 4 is placed upon the undercapsule 14, additional liquefied encapsulation grout 34 is placed within undercapsule 14. When the grouted drum 10 and overcapsule 12 are positioned within the undercapsule, the encapsulation grout 34 completely seals the port 36 and sealingly joins the overcapsule 12 to the undercapsule 14 to produce the totally encapsuled drum shown in FIGS. 5, 9 and 10.
The overcapsule 12 and the undercapsule 14 maybe formed of steel or of high strength plastic, depending upon the materials that will be utilized with them.
The encapsulation grout utilized with the present invention has been developed for its radiation shielding ability. The grout is manufactured by Wallace Construction Specialties, Ltd., 825 McKay Street, Regina, Saskatachewan, Canada. It is a blended, mass loaded polymer grout that is pumpable until it sets. It is composed of a catalyst, a resin and dense aggragate which, when combined, form a very dense durable grout. The encapsulation grout has the following physical properties:
______________________________________Density 250 lb/cu. ft.Tensile Strength (ASTM C307-61 2,400 psi (16.5 MPa)Modified)Compressive Strength 13,700 psi (94.4 MPa)(ASTM C579-75 Method B)Tensile Bond Strength (To Steel) 2,400 psi (16.5 MPa)Shrinkage: Unrestrained, Linear 0.004 in/in(SPIERF 12-64)Coefficient of Thermal Expansion 15.3 × 10.sup.-6 in/°F.70-140° F. 27.5 × 10.sup.-6 in/°C.(ASTM C531-88)Chemical Resistance Good resistance to oxidizing solutionsFlash Point - Liquid 86° F. (30° C.)Flash Point - Hardener 175° F. (80° C.)______________________________________
It will be appreciated that other types of encapsulation grout may be utilized, particularly if the hazardous waste within the drum 10 does not require radiation shielding. In some instances, common aggregate concrete may suffice for protecting the material within the drum 10.
The solidification grout, if required, will vary depending upon the hazardous waste material stored in the drums 10. Avanti International, 822 Baystar Boulevard, Webster, Tex. 77598-1528 offers a line of grout material that stabilizes and hardens various hazardous wastes that may be stored in drums. Some examples of Avanti products which may be utilized as solidification grout in the present invention are its AV-202 Multi Grout, its Scotch-Seal Chemical Grout 5600, its AV-500 High Mod Epoxy Gel, its AV-530 Epoxy Injection Resin and its AV-540 Standard Epoxy Injection Resin, It will be appreciated that other solidification grouts may be developed and utilized for the particular hazardous waste materials that may be stored inside the drum 10.
When utilized to encapsulate deteriorated drums containing hazardous wastes, the apparatus and method of the present invention permits the hazardous waste material to be stabilized before the drum is moved at all with the drum in an unmoved position, the overcapsule 12 is placed over the drum and the encapsulation grout 34 is injected between the drum and the overcapsule and permitted to harden. After hardening of the encapsulation grout, the solidification grout 38 is injected into the drum 10 thereby solidifying and stabilizing the material within drum 10. Once the solidification grout 38 is fixed within the drum 10, the entire package of the overcapsule 12 and the drum 10 may be lifted onto the undercapsule 14.
According to the provisions of the patent statutes, we have explained the principle, preferred construction and mode of operation of our invention and have illustrated and described what we now consider to represent its best embodiment. However, it should be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described. | Apparatus and method are provided for encapsuling hazardous wastes materials stored in drums. The drum is enclosed in an overcapsule that is grouted to the drum and the contents of the drum are stabilized if necessary with a solidification grout. Once the grouts have set, the overcapsule is positioned onto an undercapsule and grouted to the undercapsule so that the entire capsule with the drum containing hazardous waste inside may safely be transported and stored. The capsule is shaped so that the individual capsules may be stacked one on the other. | 1 |
RELATED APPLICATIONS
Co-pending application Ser. No. 060,408, filed July 25, 1979, now U.S. Pat. No. 4,271,839 for Dilatation Catheter Method and Apparatus shows a dilatation catheter in which dilatation is accomplished by everting a balloon from the end of a catheter, blowing the balloon up to dilate an occluded blood vessel, deflating the balloon, and re-inverting the balloon within the catheter.
Co-pending application Ser. No. 114,979 filed Jan. 24, 1980 for Flexible Calibrator shows a catheter having a calibrator bead at the distal end thereof which is used to measure the diameter of the lumen in a stenotic segment of blood vessel. The present invention comprises a calibrator bead in trailing relation to a dilatation balloon. The combination of these two elements enables the calibrator element to measure the lumen of the dilated artery rather than, as in the co-pending application, being used to measure the lumen of an occluded passage in a pre-dilated artery.
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for use in dilating occluded blood vessels and for measuring the degree of dilation of the occlusions within these vessels. Prior to the present invention these two objectives were attainable, as a result of the teachings set forth in the above-identified copending patent applications, by the use of two catheters, one having a balloon element to dilate the occlusion and the other having a calibrator element to measure the widened lumen of the occluded segment of artery. This could result in the repeated insertion and removal of catheters into and out of arteries until the sizes of the enlarged passages of the occluded segments of the arteries were of acceptable dimensions. The heavier the traffic of catheters within blood vessels the greater is the risk that material may be accidentally dislodged therefrom with possible consequent blockage elsewhere in the blood circulation system.
SUMMARY OF THE INVENTION
The present invention combines in a single catheter a dilatation balloon element and a calibrator bead element. Following dilatation of an occlusion the calibrator bead may be moved into the dilated lumen of the occlusion in order to determine whether the occlusion has been sufficiently dilated. The two objects are thereby achieved without the need of indulging in the time-consuming and hazardous activities of repeatedly removing and replacing catheters.
The principal object of the invention is to combine in a single catheter instrument dilatation balloon means which can be inflated and deflated and calibrator bead means to measure the lumen of the dilated occlusion in the artery.
This and other objects and advantages of the invention will be apparent from the following description taken in conjunction with the drawings forming part of this specification.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a semi-schematic view of the present catheter positioned adjacent an occlusion.
FIG. 2 is a similar view showing the occlusion being dilated.
FIG. 3 is a similar view showing the balloon element reinverted.
FIG. 4 is a similar view showing the catheter during the course of movement through the same artery to the next occlusion to be treated.
FIG. 5 is a view showing in elevation and longitudinal cross-section the details and construction of the present catheter with the balloon element everted.
FIG. 6 is a view like that of FIG. 5 showing the balloon element in inverted condition.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The catheter comprises a calibrator oval 10, a flexible shaft 12, a manifold 14 which serves for the connection of a syringe 16 to the instrument, a balloon 18 which is longitudinally extensible from the oval 10 under the fluid pressure applied by syringe 16 and thereafter laterally expansible under increased fluid pressure, and a guide wire 20 to be pulled to re-invert the balloon 18 within the oval 10.
A blood vessel 22 partially occluded by occlusion 24 is provided with an incision 26 for the introduction into the vessel of the catheter. The catheter is moved along the vessel until the oval 10 bears against the end of occlusion 24, as shown in FIG. 1. The syringe 16 is then attached to manifold 14 and actuated to evert the balloon 18 and extend it into the restricted lumen of occlusion 24. The fluid pressure is then increased to radially expand the balloon and compress the occlusion. The fluid pressure is then reduced by reverse operation of the syringe and the syringe is removed from manifold 14. Wire 20 is then manually pulled to re-invert the balloon within the oval. The oval is then moved within the compressed occlusion 24. Ready movability of the oval through the occlusion indicates that the occlusion has been adequately compressed. If the oval is not readily movable through the occlusion the instrument is used to further compress the occlusion. Once the occlusion has been suitably compressed the instrument may be moved further along the vessel 22, as indicated in FIG. 4, if there is a further occlusion to be treated.
The details of construction of the instrument are shown in FIGS. 5-6. The oval 10 and shaft 12 are formed by a tightly wound helical spring 28 which provides the catheter with sufficient flexibility to enable its movement through tortuous arteries. The oval and shaft are provided with an overcoating 30 of silicone, heat-shrink tubing, Teflon, or the like.
The balloon element 18 is made of an elastomeric material such as latex. One end of the balloon is attached to the end of the oval 10 and the other end of the balloon is attached with suture 32 to guide wire 20. The wire 20 is small in diameter relative to the internal diameter of spring 28 to provide an annular fluid passage between the syringe 16 and balloon 18.
Expansion of the balloon element out of the end of the catheter takes place in anisotropic fashion, with the balloon element first everting out of the catheter in advance of substantial lateral expansion, and then, after eversion, laterally expanding in response to the continued exertion of fluid pressure internally of the catheter. Optimal dimensional data for the catheter and the balloon element are set forth in my co-pending application Ser. No. 060,408.
While the invert-evert form of balloon is preferred, other types and forms of balloons may be used as long as they do not impede the movability of the catheters through the arteries and as long as they do not interfere with the use of the calibrator ovals to measure or calibrate the inside diameters of the arterial lumens. | A catheter is provided with an inflatable-deflatable balloon element to radially enlarge a partially occluded artery lumen and the catheter is provided with a calibrator oval to internally gauge the enlarged lumen. | 0 |
FIELD OF THE INVENTION
[0001] The present invention relates to culture media which provide useful environments for cellular development. More particularly this invention relates to defined culture media supplement containing constituents produced from non-traditional sources that, when added to culture media, avoid the problems of prior culture media.
BACKGROUND OF THE INVENTION
[0002] For years media supplements for culturing mammalian embryonic cells have been derived from animal fluids, and in particular blood serum. While serum based media supplements have been somewhat effective for culturing certain types of cells and tissues, these media supplements have been found to be undesirable. One of the main reasons that these serum based media supplements are unattractive candidates for culturing cells is because of the possibility that the resulting media will contaminated with impurities, toxins, and infective agents found in the fluid from which the media is derived. Additionally, because the animals from which the blood is collected are different and live in differing environments, the fluids produced by these animals have different components at differing concentrations. One important aspect of serum based medium that has been recognized is the requirement of macromolecules in the medium. In an attempt to mimic serum based products, researchers have attempted to add synthetic macromolecules, such as polyvinyl alcohol, to replace the macromolecules in the serum, such as albumin. However, because serum is largely undefined chemically, removing the serum from culture media and attempting to replace only the larger molecules has produced culture media which are less than ideal or ineffective for many purposes because the media are missing essential components.
[0003] Accordingly, there is a need for culture media supplements which are as effective as culture media supplements based on blood products while at the same eliminating potential sources of contamination. Additionally there is a need for standardized culture media.
SUMMARY OF THE INVENTION
[0004] The present invention describes a novel, physiologically based completely defined supplement to culture media for mammalian embryonic cells and gametes. This medium supplement may be used with in vitro fertilization media, embryo transfer media and embryo cryopreservation media for the mammalian preimplantation embryo, as well as a supplement to media for the development of embryonic stem cells, or any other similar media well known in the art. This supplement contains recombinant human albumin (rHA), fermented hyaluronan (HYN) and/or citrate, and combinations thereof. Addition of this supplement to the culture medium results in equivalent development compared to media supplemented with serum albumin purified from blood.
DETAILED DESCRIPTION OF THE INVENTION
[0005] The supplement may comprise recombinant human albumin (rHA) at any appropriate concentrations for the media in which it is to be used. As further described herein, the use of rHA rather than naturally occurring human serum albumin (HSA) has numerous advantages.
[0006] Typically, when the supplement comprises rHA, the supplement comprises between about 0.1 mg/ml to about 20.0 mg/ml of rHA based on the total volume of the medium to which the supplement is added. In one embodiment, about 0.5 mg/ml to about 5.0 mg/ml of rHA is added based on the total volume of the medium.
[0007] The efficacy of the supplement can be enhanced by adding fermented hyaluronan (HYN) to the supplement. The addition of the fermented HYN to the media supplement demonstrates positive results.
[0008] The phrase “increases the viability of gametes or embryonic cells” as used herein is defined as including the increased development of the embryos to the blastocyst stage in the culture, the ability to hatch from the zona pellucida is increased in vitro, and/or an increase in the overall viability of the embryo in embryo cultures when embryos are cultured in a medium containing the supplement of the present invention as compared to being cultured in the same medium without the supplement.
[0009] Furthermore, the addition of fermented HYN to the appropriate medium significantly affects the ability of the blastocysts to survive freezing. The use of fermented HYN has several advantages over the use of HYN from a naturally occurring warm blooded vertebrate source such as purified from rooster comb or umbilical cord. By utilizing fermented HYN rather than HYN from a warm blooded vertebrate source, the ability to control the safety and stability of the HYN from different sources and batches is greatly increased.
[0010] When present, the amount of fermented HYN will generally be at concentrations between about 0.1 mg/ml to about 5.0 mg/ml based on the total volume of the medium. In one embodiment the fermented HYN will be added to the medium at concentrations between about 0.125 mg/ml to about 1.0 mg/ml based on the total volume of the medium.
[0011] The supplement can be further augmented by the addition of citrate. In one embodiment, citrate and rHA are both added to the medium supplement, as it has been surprisingly and unexpectedly discovered that the addition of citrate to a medium supplement containing rHA allows the rHA to closely duplicate the properties of HSA or bovine serum albumin (BSA). The addition of the citrate has a further enhancing effect on the development of the cultured cellular material. Any citrate used for media that is well known in the art may be used, including, but not limited to, choline citrate, calcium citrate, citric acid, sodium citrate, and combinations thereof. In one embodiment, sodium citrate is used. The citrate is generally added at concentrations between about 0.1 mM and about 5.0 mM, based on the total volume of the medium. In one embodiment, the citrate is added at concentrations between about 0.1 mM and about 1.0 mM, based on the total volume of the medium.
[0012] The medium supplement of the present invention comprises rHA, fermented HYN and/or citrate in any useful combination. In one embodiment, the medium supplement, and the medium to which the medium supplement is added, is free from non-recombinant macromolecules or macromolecules purified from an animal source. In another embodiment, the medium supplement, and the medium to which the medium supplement is added, is free of non-recombinant HSA and/or non-fermented HYN.
[0013] This invention is directed to the medium supplement described above, media containing the medium supplement, a method of making the medium supplement, kits containing the medium supplement, and a method of growing embryonic material employing the medium supplement described herein.
[0014] The present invention includes a method of growing cellular material, in one embodiment embryos, employing the medium supplement described herein such that they can be included in medium at the start of culture, or can be added in a fed-batch or in a continuous manner. Moreover, the components of the medium supplement may be added together, or separately, at different stages of the media production.
[0015] This supplement can be added to any appropriate mammalian cellular material culture media well known in the art, including but not limited to, embryo culture media, embryo transfer media and embryo cryopreservation media (to include both freezing and vitrification procedures) for embryos from any mammalian species, and stem cell media. Any media that can support embryo or cell development could be used, which includes, by way of example only, bicarbonate buffered medium, Hepes-buffered or MOPS buffered medium or phosphate buffered saline. Examples of media are G1.2/G2.2, KSOM/KSOMaa, M16, SOF/SOFaa, MTF, P1, Earle's, Hams F-10, M2, Hepes-G1.2, PBS and/or Whitten's. (Gardner and Lane, 1999; Embryo Culture Systems; Handbook of In Vitro Fertilization, CRC Press, Editors: Trounson A O and Gardner D K, 2 nd edition, Boca Raton, pp 205-264.)
[0016] The production of rHA is well known in the art. In one embodiment, rHA is obtained from genetically modified yeast which produce a human albumin protein. One such methodology for the production of rHA from yeast is taught in U.S. Pat. NO. 5,612,197.
[0017] Fermented hyaluronan (HYN) is obtained by any process well known in the art. One such process is the continuous bacterial fermentation of Streptococcus equi. Hyaluronan is a naturally occurring polymer of repeated disaccharide units of N-acetylglucosamine and D-glucuronic acid. It is widely distributed throughout the body. Typically, the molecular weight of the fermented HYN is 2.3×10 6 kD. The production of HYN from Streptococcus is well known in the art, and any well known process can be used, including those disclosed in Cifonelli J A, Dorfman A. The biosynthesis of hyaluronic acid by group A Streptococcus: The uridine nucleotides of groups A Streptococcus. J. Biological Chemistry 1957; 228: 547-557; Kjems E, Lebech K. Isolation of hyaluronic acid from cultures of streptococci in a chemically defined medium. Acta Path. Microbiol. Scand. 1976 (Sect. B); 84: 162-164; and Markovitz A, et al. The biosynthesis of hyaluronic acid by group A Streptococcus. J. Biological Chemistry 1959; 234(9): 2343-2350.
[0018] Other compounds may be added to the medium supplement of the present invention. These include growth factors, as mammalian embryos and cells typically have many receptors for growth factors and the addition of such growth factors may increase the growth rate of the cultured material. Such growth factors include, but are not limited to, Insulin, typically in amounts of 0.1-100 ng/ml; IGF II, typically in amounts of 0.1-100 ng/ml; EGF, typically in amounts of 0.1-100 ng/ml; LIF, typically in amounts of 5-1000 U/ml; PAF, typically in amounts of 0. 1-500 μM; and combinations thereof. All amounts are based on the total volume of the media to which the medium supplement is added.
[0019] Medium supplement can be prepared in 2 ways, either as a separate medium supplement that is added to the media after media preparation, or the ingredients of the medium supplement can be added directly to the culture media during media preparation.
[0020] By way of example only, the medium supplement may be prepared on its own as follows. Medium supplement rHA may be made into a stock solution by adding either water, saline or medium to make a concentrated stock solution of between 50-500 mg/ml, usually 250 mg/ml. Alternatively, the solution can be obtained as a 250 mg/ml stock solution. Fermented HYN is reconstituted in water, saline or medium, to make a concentrated stock solution of between 10-500 mg/ml, usually 500 mg/ml. This is achieved by adding the water, saline or medium to a flask and adding the desired amount of HYN to the solution. The HYN is then dissolved by rigorous shaking or mixing using a stir bar. For a 500 mg/ml solution, 500 mg of HYN can be added to 1 ml of solution. Citrate is prepared as a stock solution by adding either water, saline or medium to make a concentrated stock solution of between 5-500 mM, usually 500 mM. For a 500 mM stock solution, 0.9605 g of citric acid is added to 10 ml of solution. The rHA, fermented HYN and citrate stocks are added together to make a single supplement solution that is added to the final medium as a 100×times concentrated stock. For 10 ml of medium, 100μl of the supplement is added.
[0021] rHA can be added directly to the culture medium as either a powder or as a stock solution. The following embodiment is presented by way of example only. The stock solution may added as 100μl of 250 mg/ml stock to 9.9 mls of medium. Fermented HYN may be added directly to the culture medium as either a powder or as a stock solution. As a powder, 1.25 mg of HYN may be added to 10 ml of medium. Alternatively, a 125μl of a 1% stock solution may be added to 9.9 ml of medium. Citrate may be added directly to the culture medium as either a powder or as a stock solution. As a powder, 9.6 mg may be added to 100 mls of medium, or alternatively, 100μl of a 50 mM stock may be added to 9.9 ml of medium.
[0022] All patents and publications cited herein are hereby incorporated by reference.
[0023] All ranges recited herein include all combinations and subcombinations included within that range limits; therefore, a range from “about 0.1 mg/ml to about 20.0 mg/mil” would include ranges from about 0.125 mg/ml to about 11.5 mg/ml, about 1.0 mg/ml to about 15.0 mg/ml, etc.
[0024] The medium supplement of the present invention solves several problems that persist in the art of culturing mammalian cells, tissues, embryos and other related cellular material. One problem with current media is that the cultured mammalian cellular material, particularly embryos, may become contaminated by contaminants such as prions and/or endotoxins found within macromolecular blood products such as human albumin. An advantage of the supplement of the present invention is that it eliminates the potential contamination associated with the use of blood products in media for culturing embryo and other mammalian cellular materials.
[0025] Another problem with current media is the difficulty in standardizing such media when using blood products such as serum albumin or other naturally occurring materials. Furthermore, the present invention makes it easier to purify the final cultured product, when the naturally occurring variations and contaminants within the blood products in the media are eliminated.
[0026] The present invention eliminates the inherent variation involved when using a biological protein which is often contaminated with other molecules and which differs significantly between different preparations and also between batches within the same preparation. Therefore, the use of recombinant molecules such as rHA enables the formulation of physiological media to be prepared in a standardized fashion. These preparations are endotoxin free, free of prions and are more physiologically compatible than media which are currently used. Current media contain other synthetic macromolecules, such as polyvinyl alcohol or polyvinyl pyrrolidone, which are unable to perform essential physiological functions, such as bind growth factors, and therefore the use of these media result in inferior development of mammalian cellular material.
[0027] The invention will be better understood from the Examples which follow. However, one skilled in the art will readily appreciate that the specific compositions, methods and results discussed are merely illustrative of the invention and no limitations on the invention are implied.
EXAMPLES
Example 1
[0028] Media G1.2/G2.2 were prepared from concentrated stock solutions as shown below in Table 1. rHA was added as a 250 mg/ml stock solution of 200 μl to 9.8 mls of media. Initial experiments have investigated replacing albumin purified from blood with the rHA for outbred mouse embryo development in culture. Fertilized eggs were cultured for 4 days in one of 3 different concentrations of rHA. Embryos were cultured at 37° C. in 6% CO 2 :5% O 2 :89% N 2 in an embryo incubation volume of 10 embryos:20 μl of medium. Embryos were cultured in medium G 1.2 for 48 h followed by 48 h of culture in medium G 2.2. The negative control treatment was no protein, the positive control treatment was 5 mg/ml HSA (blood product). The results are shown below in Table 2.
TABLE 1 G1.2 G2.2 FG1 Stock Expires Components (g/L) (g/L) (g/L) A 3 months NaCl 5.26 5.26 5.844 ×10 conc KCl 0.41 0.41 0.41 NaH 2 PO 4 —H 2 O 0.035 0.035 0.078 MgSO 4 —7H 2 O 0.246 0.246 0.246 Na Lactate 1.17 0.66 0.58 Glucose 0.09 0.568 0.567 Penicillin 0.06 0.06 0.06 B 1 week NaHCO 3 2.101 2.101 2.1 ×10 conc Phenol Red 0.001 0.001 0.001 C 2 weeks Pyruvic Acid 0.0352 0.011 0.0352 ×100 conc D 1 month CaCl 2 —H 2 O 0.265 0.265 0.265 ×100 conc G 3 months alanyl-Glutamine 0.108 0.217 — ×100 conc T 3 months Taurine 0.0125 — 0.0125 ×100 conc ED 1 month EDTA 0.029 — — NaOH solution 0.4 N Non-Essential 10 ml 10 ml 10 ml ×100 soln Amino Acids E Essential Amino — 20 ml — ×50 soln Acids V Vitamins — — 10 ml ×100 soln 10 mls
Stock A and B
[0029] 1. Weigh out individual components into a 100 ml flask.
[0030] 2. Add 50 ml of H 2 O (either Extreme H 2 O or Biowittaker).
[0031] 3. Mix well until all components are dissolved.
[0032] 4. Add a further 50 ml of H 2 O.
[0033] 5. Mix well.
[0034] 6. Filter through 0.2 μm filter.
[0035] 7. Store at 4 degrees Celsius.
Stock C-T
[0036] 1. Weigh component into a 10 ml tube.
[0037] 2. Add 10 ml of H 2 O (either Extreme H 2 O or Biowittaker).
[0038] 3. Mix well until dissolved.
[0039] 4. Filter through 0.2 μm filter.
[0040] 5. Store at 4 degrees Celsius.
Embryo Culture Media Preparation—Part I
Stock EDTA
[0041] 1. Weigh 0.029 g of EDTA into a 10 ml tube.
[0042] 2. Weigh 0.4 g of NaOH into a separate 10 ml tube.
[0043] 3. Add 10 ml of H 2 O (either Extreme H 2 O or Biowittaker) to NaOH and mix until dissolved.
[0044] 4. Add 220 μl of NaOH solution to EDTA.
[0045] 5. Mix until dissolved.
[0046] 6. Add 9.8 ml of H 2 O to the EDTA.
[0047] 7. Add 90 ml of H 2 O to a 100 ml flask.
[0048] 8. Add 10 ml of EDTA solution to the 90 ml of H20.
[0049] 9. Filter through 0.2 μm filter.
[0050] 10. Store at 4 degrees Celsius.
TABLE 2 Cell ICM TE % rHA mg/ml Blastocyst Hatching Number Number Number ICM/Total 0 76.7 31.7 60.8 ± 2.2 a 13.8 ± 0.7 a 47.1 ± 2.0 a 23.0 ± 0.9 1.25 70.7 46.6 72.6 ± 2.2 bc 17.7 ± 0.6 b 56.4 ± 1.9 bc 24.0 ± 0.6 2.5 75 39.3 78.1 ± 2.5 b 18.4 ± 0.5 b 58.4 ± 2.1 b 24.2 ± 0.5 5 76.8 37.5 65.9 ± 2.7 ac 16.3 ± 0.7 b 49.6 ± 2.4 ac 25.2 ± 0.7 HSA 5 mg/ml 72.6 38.7 74.3 ± 2.4 bc 17.2 ± 0.7 b 56.2 ± 2.0 bc 23.6 ± 0.6
[0051] rHA was able to replace HSA for embryo development in culture for at least concentrations of 1.25 to 2.5 mg/ml.
Example 2
[0052] Media G1.2/G2.2 were prepared from concentrated stock solutions as taught in Example 1. Fermented HYN was added from a ×100 stock solution of 100 μl to 10 mls of media.
[0053] Initial experiments investigated replacing albumin purified from blood with HYN for outbred mouse embryo development in culture. Fertilized eggs were cultured for 4 days in one of 4 different concentrations of HYN. Embryos were cultured at 37° C. in 6% CO 2 :5% O 2 : 89% N 2 in an embryo incubation volume of 10 embryos:20μl of medium. Embryos were cultured in medium G1.2 for 48 h followed by 48 h of culture in medium G2.2. The negative control treatment was no protein. The results are shown below in Table 3.
TABLE 3 HYN (mg/ml) Blastocyst Hatching Cell Number ICM Number TE Number % ICM/Total 0 82.4 a 38.3 a 67.3 ± 2.8 a 16.1 ± 0.7 a 50.3 ± 2.3 a 24.6 ± 0.8 a 0.125 88.6 a 57.1b c 79.6 ± 1.9 bc 21.2 ± 0.8 bc 58.7 ± 1.5 bc 26.5 ± 0.6 ac 0.25 94.5 a 72.7 c 74.9 ± 3.4 bc 21.8 ± 1.2 bc 51.9 ± 2.8 ac 29.7 ± 0.8 bc 0.5 100 a 50 b 64.2 ± 1.9 ac 18.0 ± 0.7 ac 46.7 ± 2.0 a 28.3 ± 1.1 bc 1 61.8 b 23.5 a 62.0 ± 2.7 ac 17.5 ± 0.8 ac 49.1 ± 2.5 a 26.4 ± 0.9 ac
[0054] Fermented HYN at least of concentrations from 0.125 to 0.5 mg/ml stimulated mouse embryo development.
Example 3
[0055] Media G1.2/G2.2 were prepared from concentrated stock solutions as taught in Example 1. rHA was added as a 250 mg/ml stock solution of 200 μl to 9.8 mls of media, fermented HYN was added from a ×100 stock solution of 100 μl to 10 mls of media. Subsequent experiments investigated replacing albumin purified from blood with rHA together with fermented HYN for outbred mouse embryo development in culture. Fertilized eggs were cultured for 4 days. Embryos were cultured at 37° C. in 6% CO 2 :5% O 2 :89% N 2 in an embryo incubation volume of 10 embryos:20 μl of medium. Embryos were cultured in medium G 1.2 for 48 h followed by 48 h of culture in medium G 2.2. The results are shown below in Table 4.
TABLE 4 Cell ICM TN Treatment Number Number Number % ICM/Total 5 mg/ml HSA 73.3 ± 17.8 ± 0.6 55.5 ± 1.3 24.3 ± 0.5 1.7 1.25 mg/ml rHA + 71.8 ± 18.6 ± 0.5 53.2 ± 1.3 26.0 ± 0.5* 0.125 mg/ml HYN 1.6
[0056] Culture with rHA and fermented HYN together significantly increase the development of the inner cell mass cells (ICM). Since ICM development is linearly related to ability to develop into a viable fetus, an increase in % ICM is likely to mean an increase in viability.
Example 4
[0057] Media G1.2/G2.2 were prepared from concentrated stock solutions as taught in Example 1. rHA was added as a 250 mg/ml stock solution of 200 μl to 9.8 mls of media, fermented HYN was added from a ×100 stock solution of 100 μl to 10 mls of media. Subsequent experiments investigated replacing albumin purified from blood with rHA together with fermented HYN for outbred mouse embryo development after transfer to recipient mice. Fertilized eggs were cultured for 4 days and then transferred at the blastocyst stage to recipient females. Embryos were cultured at 37° C. in 6% CO 2 :5% O 2 :89% N 2 in an embryo incubation volume of 10 embryos:20 μl of medium. Embryos were cultured in medium G1.2 for 48 h followed by 48 h of culture in medium G2.2. The results are shown below in Table 5.
TABLE 5 Fetal Fetus/ Implantation development implantation rate (%) (%) site (%) Weight (mg) HSA 63.3 43.3 68.4 208 rHA and HYN 65.0 46.7 71.8 207
[0058] Culture with rHA together with fermented HYN resulted in equivalent fetal development to those embryos cultured in medium supplemented with HSA (blood product).
Example 5
[0059] Media G1.2/62.2 were prepared from concentrated stock as taught in Example 1. rHA was added as a 250 mg/ml stock solution of 200 μl to 9.8 mls of media, fermented HYN was added from a ×100 stock solution of 100 μl to 10 mls of media and citrate was added from a ×100 stock solution of 100 μl to 10 mls of media. Experiments were performed to determine whether the further supplementation of rHA and fermented HYN together with citrate increased mouse embryo development in culture. Embryos were cultured from the fertilized egg for 48 h with rHA and HYN in the presence or absence of citrate. Embryos were cultured at 37° C. in 6% CO 2 :5% O 2 :89% N 2 in an embryo incubation volume of 10 embryos:20 μl of medium. Embryos were cultured in medium G1.2 for 48 h. The results are shown below in Table 6.
TABLE 6 Day 3 mean cell number % 8 cell % compacted no citrate 6.33 ± 0.17 69.7 7.3 citrate 7.21 ± 0.13* 81.1* 12.2*
[0060] The addition of citrate to medium containing rHA and fermented HYN resulted in a significant increase in embryo development.
Example 6
[0061] Media G1.2/G2.2 were prepared from concentrated stock solutions as taught in Example 1. rHA was added as a 250 mg/ml stock solution of 200 μl to 9.8 mls of media, fermented HYN was added from a ×100 stock solution of 100 μl to 10 mls of media and citrate was added from a ×100 stock solution of 100μl to 10 mls of media. Experiments were performed to determine whether the further supplementation of rHA and fermented HYN together with citrate increased mouse embryo development in culture. Embryos were cultured from the fertilized egg for 48 h with rHA and HYN in the presence or absence of citrate. Embryos were then transferred to culture medium with or without citrate for a further 48 h. Embryos were cultured at 37° C. in 6% CO 2 :5% O 2 :89% N 2 in an embryo incubation volume of 10 embryos:20 μl of medium. Embryos were cultured in medium G1.2 for 48 h followed by 48 h of culture in medium G2.2. The results are shown below in Table 7.
TABLE 7 Morula/ Total Hatching % Blastocyst Blastocyst (% of Cell ICM TE ICM/ Treatment (%) (%) Total) Number Number Number Total −/− 53.9 45.2 13 100.4 28.9 71.5 28.4 +/− 71.3 67.3 16.8 112.6 34.9 77.7 30.7 −/+ 68.5 64.8 23.2 94.8 33.4 61.44 34.5 +/+ 72.7 62.7 18.2 100.7 30.9 69.8 30.4
[0062] As can be seen by the results in Table 7, the addition of citrate significantly increased embryo development.
Example 7
[0063] Media G1.2/G2.2 were prepared from concentrated stock solutions as taught in Example 1. rHA was added as a 250 mg/ml stock solution of 200 μl to 9.8 mls of media, fermented HYN was added from a ×100 stock solution of 100 μl to 10 mls of media and citrate was added from a ×100 stock solution of 100 μl to 10 mls of media.
[0064] Initial experiments in the cow have investigated replacing albumin purified from blood (Bovine serum albumin, BSA) with either rHA or fermented HYN or rHA together with fermented HYN for the development of fertilized eggs in culture. Fertilized eggs were cultured for 6 to 7 days. Embryos were cultured at 38.5° C. in 6% CO 2 :5% O 2 :89% N 2 in 500 μl of medium. Embryos were cultured in medium G1.2 for 72 h followed by 72 h of culture in medium G2.2. The results are shown below in Table 8.
TABLE 8 Number of Total Blastocyst Total Blastocyst Treatment Embryos Day 6 Day 7 BSA 592 30.9 a 36.8 rHA 583 22.1 b 38.4 HYN 549 16.9 b 30.4 rHA + HYN 558 27.8 a 39.1
[0065] The combination of both rHA with the fermented HYN produced equivalent embryo development in culture of cow embryos as that obtained in the presence of BSA.
Example 8
[0066] Media G1. 2/G2.2 were prepared from concentrated stock solutions as taught in Example 1. rHA was added as a 250 mg/ml stock solution of 200 μl to 9.8 mls of media, fermented HYN was added from a ×100 stock solution of 100 μl to 10 mls of media and citrate was added from a ×100 stock solution of 100 μl to 10 mls of media.
[0067] Subsequent experiments in the cow have investigated replacing albumin purified from blood (Bovine serum albumin, BSA) with rHA with or without citrate for the development of fertilized eggs in culture. Fertilized eggs were cultured for 6 to 7 days. Embryos were cultured at 38.5° C. in 6% CO 2:5 % O 2 :89% N 2 in 500 μl of medium. Embryos were cultured in medium G1.2 for 72 h followed by 72 h of culture in medium G2.2. The results are shown below in Table 9.
TABLE 9 Total Day 6 Blastocyst Blastocyst Day 6 Blastocyst Inner Cell Mass Treatment Day 6 Cell Number Cell Number BSA 40.2 143 ± 6 a 46.2 ± 1.9 a rHA 36.6 123 ± 7 b 37.9 ± 1.9 b rHA + citrate 41.4 146 ± 5 a 45.3 ± 1.9 a
[0068] Supplementing rHA with citrate resulted in equivalent cow embryo development in culture compared to those embryos cultured in the presence of BSA.
Example 9
[0069] Media G1.2/G2.2 were prepared from concentrated stock solutions as taught in Example 1. rHA was added as a 250 mg/ml stock solution of 200 μl to 9.8 ml of media, fermented HYN was added from a ×100 stock solution of 100 μl to 10 ml of media and citrate was added from a ×100 stock solution to 10 ml of media.
[0070] Subsequent experiments in the cow have investigated addition of fermented HYN to rHA with citrate for the development of fertilized eggs in culture, and subsequent ability to freeze them. Fertilized eggs were cultured for 6 to 7 days. Embryos were cultured at 38.5° C. in 6% CO 2 :5% O 2 :89% N 2 in 500 μl of medium. Embryos were cultured in medium G1.2 for 72 h, followed by 72 h of culture in medium G2.2. Blastocysts were either stained for cell numbers or frozen and subsequently thawed to assess survival. The results are shown below in Table 10.
TABLE 10 Total Day 7 Survival and Blastocyst Blastocyst Re-expansion Treatment Day 7 Cell Number Following Freezing BSA 42.3 150 ± 10 38.5 a rHA + citrate 50.0 134 ± 10 57.1 b rHA + citrate + HYN 51.1 159 ± 10 80 c
[0071] Supplementing medium with rHA, citrate and fermented HYN significantly increased the ability of blastocysts to survive freeing and thawing.
Example 10
[0072] Media G1.2/G2.2 were prepared from concentrated stock solutions as taught in Example 1.
[0073] This experiment investigated the effects of growing CF1 mouse embryos in culture in the presence of rHA and HYN on the ability of the embryos to survive freezing and thawing. CF1 mouse embryos were cultured to the blastocyst stage and development and ability to survive the freezing procedure was assessed.
TABLE 11 Development to the Blastocyst Hatching Re-expansion After Hatching After Completely Hatched Treatment Blastocyst Stage (%) Rates (%) Freezing (%) Freezing (%) After Freezing HSA 88.2 49.0 76.1 42.9 28.6 HSA + HYN 81.8 43.2 79.5 45.5 29.6 rHA + citrate 85.0 53.4 77.5 57.5* 40.0* RHA + citrate + HYN 79.0 51.9 83.8 67.6* 51.3*
[0074] From these results it can be clearly seen that culture with rHA or rHA with HYN significantly increases blastocyst hatching after thawing compared to blastocysts grown with HSA (P<0.05).
[0075] The ability of the blastocysts to outgrow in culture following cryopreservation was also assessed. The outgrowth of both the ICM and TE was scored between 0-3 where 0 represented no outgrowth and 3 represented extensive outgrowth. Outgrowth has been shown to be related to viability (Lane and Gardner, 1997).
TABLE 12 Attachment Outgrowth of Outgrowth of Treatment (%) ICM (%) TE (%) HSA 89.5 0.8 ± 0.1 1.8 ± 0.1 HSA + HYN 91.2 2.2 ± 0.1* 1.7 ± 0.1* rHA + citrate 85.0 1.8 ± 0.1* 1.6 ± 0.1* rHA + citrate + HYN 86.8 2.1 ± 0.1* 1.9 ± 0.1*
[0076] As can be seen from Table 12, development of the ICM was increased by culturing the embryos in a medium containing rHA or HYN as compared to embryos cultured in human serum albumin.
Example 11
[0077] This example illustrates that a medium containing rHA, HYN and citrate allows for the successful expansion of cryopreserved supernumerary blastocysts.
[0078] In this example, donated cryopreserved human pronucleate embryos were thawed and cultured in medium G1.3 for 48 hours followed by culturing in medium G2.3, as taught in U.S. patent application Ser. No. 09/201,594 with the following changes. The G1.2-G1.3 media has a MgSO 4 concentration from 1.0 to 1.8 and a CaCl 2 concentration from 1.8 to 1.0. The changes for the G2.2-G2.3 media are the same as the changes to the G1 media, with the addition on the essential amino acids added at half the concentration and nicotinamide, inositol, and folic acid are not present.
[0079] Both media were supplemented with 2.5 mg/ml rHA and 0.125 mg/ml HYN. The freezing solution for the embryos was 4.5% glycerol and 0.1M sucrose (10 min.) followed by 9% glycerol and 0.2M sucrose (7 min.). The embryos were placed in a freezing machine at −6° C., seeded and held for 10 minutes, followed by cooling at 0.5° C. per minute to −32° C. The embryos were then plunged into liquid nitrogen. Immediately post thaw, the embryos were incubated individually in 500 nl of fresh G 2.3 for 4 hours after which they were placed individually in 10 microliters of G 2.3 for overnight culture. All incubations took place in 5% O 2 :6% CO 2 :89% N 2 . The 500 nl samples of media were frozen and analyzed using ultramicrofluorescence. The glucose and pyruvate uptake of the thawed embryos was also measured.
TABLE 13 Mean Mean Number of Number of Glucose Pyruvate Blastocysts Blastocysts Uptake Uptake Completely Completely Number of (pmol/ (pmol/ Expanded Hatched Blastocysts embryo/h) embryo/h) After 24 h After 24 h 16 40.6 15.2 12 (75%) 5 (31%)
Example 12
[0080] The IVF protocol as outlined in Gardner et al. 1988 and Schoolcraft 1999 were used in this example.
[0081] This example demonstrates the advantages of a medium containing rHA, HYN and citrate on the development of human embryos.
TABLE 14 Number of Resulting Implantation Treatment Group Patients Pregnancies Rates HSA 10 7 (70%) 32.8% RHA + citrate + HYN 12 9 (66.7%) 31.9% | The present invention provides a supplement and a culture media useful for culturing mammalian gametes and embryonic tissue. The culture media comprises at least one of recombinant human albumin, fermented hyaluronan, and citrate. Because the constituents are produced from non-conventional sources, the culture medium is free from contaminants such as viruses, prions and endotoxins. Additionally, because the medium is completely defined, the medium is not subject to variations which can impair the development of mammalian cells and prevent meaningful comparisons of empirical studies. | 2 |
TECHNICAL FIELD OF THE INVENTION
[0001] The present invention relates to a system for chemically bonded ceramic (CBC) materials, preferably a dental filling material or an implant material, comprising a two-step procedure. This system includes an initial working part-system to provide for improved early-age properties and a second main system to provide for improved end-product properties including bioactivity. The systems interact chemically. The invention also relates to the powdered materials and the hydration liquid, respectively, as well as the formed ceramic material.
BACKGROUND ART
[0002] The present invention relates to binding agent systems of the hydrating cement system type, in particular cement-based systems that comprise chemically bonded ceramics in the group that consists of aluminates, silicates, phosphates, carbonates, sulphates and combinations thereof, having calcium as the major cat-ion, and in addition to said system a second early age binding system is included. The invention has been especially developed for biomaterials for dental and orthopaedic applications, both fillers and cements as well as implants including coatings and carriers for drug delivery, but can also be used as fillers in industrial applications in electronics, micro-mechanics etc or in the construction field.
[0003] For materials, such as dental fling materials and implants, that are to interact with the human body, it is an advantage that the materials are made as bioactive or biocompatible as possible. Other properties that are required for dental filling materials and implants are a good handling ability with simple applicability in a cavity, moulding that permits good shaping ability, hardening/solidification that is sufficiently rapid for filling work without detrimental heat generation and provides serviceability directly following therapy, high hardness and strength, corrosion resistance, good bonding between filling material and biological wall, dimensional stability, radio-opacity, good long time properties and good aesthetics especially regarding dental filling materials. For the purpose of providing a material that fulfils at least most of these required properties, materials have been developed, such as those described in e.g. SE 463,493; SE 502,987; WO 00/21489; WO 01/76534; WO 01/76535; PCT/SE02/01480; and PCT/SE02/01481.
SUMMARY OF INVENTION
[0004] This invention relates especially to the combination of improved early-age properties (properties achieved within the first ten minutes up to some hours) and the property development towards the final stage, which for different properties are achieved after some days or weeks. The present invention specifically relates to the problems of initial moulding ability, initial strength, heat evolved and early colour/transmittance development as well as high strength, viscoelasticity and other mechanical properties, i.e. the problem of enabling optimisation of a complex property profile in a bioactive product, and at the same time, also of the property profile of a the system during processing of the same to form the product.
[0005] The chemically bonded ceramic system for dentistry based on calcium aluminate minerals has two drawbacks related to initial strength and possible expansion. The final strength is reached after about 7 days, but the strength during the first hour is lower than that of a temporary filing material. The magnitude of the expansion may be too high not to raise questions from the dental community. According to ISO 1559 an amalgam restorative should have a dimensional stability within—0.15 to +0.2 linear %. The level 0.2% can be obtained in the Ca-aluminate based system, but expansion close to zero is desirable.
[0006] For orthopaedic applications an additional question deals with the heat evolved during the initial setting and hardening. This is more pronounced for treatments where larger amounts of biomaterial are injected.
[0007] The present invention addresses these issues for biomaterials based on chemically bonded ceramics. A low initial strength can cause failures during the first 24 hours and a somewhat too high expansion may cause tooth cracking in weakened teeth after the replacements of earlier fillings. The crucial question is how to increase the initial strength without affecting the final properties negatively, and is not a straightforward matter and demands a careful microstructural design. The use of two periods with different chemistry involved as in the present invention solves the problem with initial desired features of the biomaterial and the end-product characteristics.
[0008] Accordingly, the present invention aims at providing a system for CBC-based materials, preferably biomaterials, having improved controllability concerning its initial viscosity and consistency as well as heat evolved upon mixing of the powdered material and the hydration liquid of the system and early-age properties (initial strength, pore closure, translucency and early obtained bioactivity) and optimal end-product properties such as mechanical properties including compressive and bending strength and a sufficiently high E-modulus, a certain viscoelasticity and appropriate hardness, in the hydrated CBC-based product. This combination of improved initial properties and final properties is achieved by using an optimised combination of chemically compatible systems, where the first system is working in the initial phase in combination with the main system. The overall system works with pH-changes that are set by the selected part systems. The present invention is related to a pH controlled combination of a rapidly formed phase, primarily controlled by cross-linking chemistry and an overall acid-base reaction of chemically bonded ceramic type, primarily controlled by hydration chemistry. The control of pH is essential in transforming the initial acid system into a bioactive system, i.e. conditions for apatite formation. The rapid change into high pH-values reduces the risk of metal release.
[0009] These and other objectives are attained by the system, the powdered material (i.e. the inorganic binding phase and reactive glass), the hydration liquid and the ceramic material according to the invention, as defined in the claims.
[0010] According to one aspect of the invention, the powdered material and/or the hydration liquid comprises an additive of polyacrylic acid and/or a salt thereof or other polycarboxylic acids, co-polymers thereof, or polycarboxylates (i.e. a salt or ester of a polycarboxylic acid), all of which refer to the PAA-system.
[0011] By the inventive addition of a polycarboxylic acid or a copolymer or a salt or an ester thereof in the powdered material and/or in the hydration liquid, the following reactions take place during dissolving, hydration and polymerisation, here exemplified by a reaction between poly(acrylic-co-maleic acid) and calcium aluminate. R can be any group one ion (i.e. H + , Li + , Na + , K + , Rb + , preferably H + , Na + and K + ) or NH 4 + , and M could be a metal ion (e.g. Al 3+ , Ca 2+ , Sr 2+ , Si 4+ ).
[0000]
[0012] The organic hydrophilic system is not restricted to PAA-systems, but may also be based on other polycarboxylic acids, e.g. poly(maleic acid), poly(itaconic acid) or tricarballylic acid) or carboxylates such as phosphate esters. Also, polymers such as PAA/PEG can be used.
[0013] The source of the cross-linking metal ions (Ca, Al, Si, Sr . . . ) is addition of reactive glasses and the Ca-based cement material. Reactive glasses are preferably water soluble silicate glasses with Ca, Sr and/or Al as substitute ions for Si, e.g. glasses of the basic system (CaO SrO,Al 2 O 3 )-SiO 2 with high divalent ions contents.
[0014] The function of the poly acrylic acid or a salt (PAA) thereof can be divided into dispersing ability and cross-linking. As is understood, in the case with the cross-linking poly acid, the powdered material (the reactive glass and the calcium based cement material) is first dissolved in the liquid, thereafter Ca- and Al-ions cross-links the polyacrylic acid to form a polyacrylate polymer, and other Ca- and Al-ions hydrate to form hydrated calcium aluminate material in a second step. The resulting, hydrated material is a composite of CBC material and a cross-linked polyacrylate polymer. For an optimised formation of the two part composite—a biomer—the CBC system requires Ca-aluminate or Ca-silicate, reactive glass, e.g. of glass ionomer type, the composition of which is at least as soluble as traditional bioactive glasses, a poly acrylic acid and/or a salt thereof and inert filler particles, e.g. dental glass. The initial low pH of the system induces a dissolution of both the reactive glasses and the basic Ca-aluminate system or other chemically bonded ceramics of the same type, e.g. Ca-silicates.
[0015] Thus, binding phases may work during separate periods of time, or overlapping periods of time in the overall hardening process facilitating the combination of potential early-age properties with high performance end features especially related to biomechanical and biochemical properties.
DETAILED DESCRIPTION OF THE INVENTION
[0016] As compared to the survey article on medical and scientific products by L. H. Hench “Engineered Materials Handbook” Vol 4, ASM International 1991, pp1007-1013, (especially Figures 1 and 2, p. 1008), the present invention deals with bioactive materials of an additional type, the type of which could be defined as type 5, i.e. with even faster dissolution and precipitation of phases than in the traditional bioactive glasses and/or resorbable materials. This is accomplished by the use of soluble glasses and the inorganic cement.
[0017] One route according to the present invention that yields surprisingly good initial results and improved final properties is to make a hybrid material of a glass ionomer cement and minerals of calcium aluminate and/or calcium silicate, maintaining a bioactive feature of the system. Glass ionomer cements consist of glass and poly acrylic acid. The acid dissolves the glass, and the ions from the glass cross-link the acid, and the material hardens. The reaction is rather rapid and nearly final strength is reached after about one hour. By exchanging fractions of the glass for calcium aluminate or silicate and a corresponding fraction of the PAA for water (with accelerator) a hybrid material can be formed. The liquid contents are controlled via
[0000]
w
c
c
+
P
A
A
reactive_glass
+
w
G
I
C
reactive_glass
[0000] with a 0.2<w c /c<0.45 (refers to the inorganic cement system), 0<PAA/(reactive glass)<0.21 and 0.2<w GIC /(reactive glass)<0.45 (refers to the glass ionomer system). All ratios refer ratios by weight.
[0018] In the formula c=inorganic cement;
[0000] w c =water to react with inorganic cement;
w GIC =water to react with reactive glass, and
w (i.e. total water)=w c +w GIC .
[0019] The PAA can be applied as a solution and/ or as solid acid component.
[0020] Since the initial pH is acidic, the PAA reaction occurs first and as the acid is cross-linked the pH increases and the hydration of the Ca-aluminates continues. The material has a much higher initial strength than that of the pure ceramic system. The final strength is higher than that of the GIC. The microstructural variables are controlled by the reactive glass, the poly acrylic acid including the pH, the Ca-aluminate or Ca-silicate and inert fillers, e.g. dental glass particles or glass fibers.
[0021] The initial solution should have a pH<7, preferably 1-4, enhancing the cross-linking of the polycarboxylic. The pH increases when the polycarboxylic system meets the CA-system, resulting in a basic overall system at pH>7. The amounts of the polyacrylic acids are controlled to maintain pH<7 up to 30 minutes. After final hydration the pH approaches neutrality from the basic side. One problem with pure Glass Ionomer systems, which are based on polycarboxylic is the corrosion resistance sensitivity. The basic CAH system neutralises the initial acidity in the polyacrylic systems. The present invention could be looked upon as a two-phase biomaterial composed of two different biomaterials where the first is activated to take care of necessary early-age phenomena and the second biomaterial to establish the property profile of the end-product, included being a bioactive material.
[0022] The control of pH, especially the effect of obtaining a pH>7 early in the process—after initial acidic condition—is essential in transforming the initial acid system into a bioactive system, i.e. conditions for apatite formation, the requirements of which is high pH and a chemical surrounding of ions including calcium, phosphate and hydroxyl ions—the phosphate ions originating from phosphate glass, body liquid or from P-containing bonding materials, the hydroxyl ions from the dissolution of the Ca-aluminate system or added bases, preferably Li-hydroxide and/or Ca-hydroxide. The high pH contributes to formation of aluminate ions (Al(OH) 4 -) instead of aluminium ions (Al 3+ ).
[0023] Reactive filler particles in the present invention are composed of reactive glass, a phosphorous-containing glass and chemically bonded ceramics, preferably Ca-aluminates, preferably CA=(CaO)(Al 2 O 3 ), C 12 A 7 =(CaO) 12 (Al 2 O 3 ) 7 ) and C 3 A=(CaO) 3 (Al 2 O 3 ) and/or CS=(CaO SiO 2 ), C 2 S=(2CaO SiO 2 ), and C 3 S=(3CaO SiO 2 ), the latter preferably for orthopaedic applications. The composition of the reactive glass, especially the dissolution rate, is crucial. The glass grain size is also important and should be below 40 micron. The pure PAA gives an earlier general cross-linking reaction. Addition of a salt of the PAA is important in achieving improved viscosity at a low w/c. The inert filler is essential for the general end-product microstructure. Its effect concerns a lowered expansion, increased radio-opacity and favoured mechanical properties, especially hardness and fracture toughness.
[0024] Concerning calcium aluminate phases it is preferable to use CA, C 12 A 7 and C 3 A, which yield good initial strength. The addition of accelerator is dependant upon the selection of the Ca-aluminate phase. Low concentrations of lithium ions increase the reaction rate for CA. For C 12 A 7 and C 3 A the effect of accelerator is more complex.
[0025] According to another aspect of the invention addition of a base is included to achieve a change of pH to a high pH>7, more preferably pH>10 after an initial “acidic” time period of approximately 5 minutes. This is to assure an optimised hydration speed.
[0026] According to another aspect of the invention addition of a further acid is included to keep the pH<7 during a prolonged time of up to 30 minutes. This is to assure an optimised time for complete cross-linking of the acid.
[0027] Ways to induce such additional (delayed and then rapid) pH changes include release of acids/bases from a porous material (preferably nano/meso-pore structure or zeolite type structures). An additional way is coating of the particle surfaces to control the release/dissolution of pH changing species, especially the CBCs material, e.g. Ca-aluminate phases by coating with for instance Na-glyconate.
[0028] The active acids can be introduced either as dried substance together with the inorganic cement or as liquid in the hydration liquid or as a combination of both dry an active acid raw material and a liquid solution of the active acid.
[0029] Suitably, said polycarboxylic has a molecular weight of 100-250,000, preferably 1000-100,000 and it is present in an amount of up to 30%, preferably 1-20% and most preferred 3-15% by weight, calculated on the powdered material including any dry additives for dental applications.
[0030] It is preferred that the system comprises inert dental glass, as an additive in the powdered material, preferably at a content of 3-30 weight-% more preferred 5-20%. The particle size is critical in establishing high homogeneity. It is preferred that the particle size is 0.1-5 μm, more preferable 0.2-2 μm, and most preferable 0.3-0.7 μm. The dental glass may contain low additional amounts of less stable glass or reactive glass, preferable below 10% of the glass content. These glasses can preferably contain fluorine and phosphorus to yield fluoride ions, which contribute to F-apatite formation. According to the present invention the translucency is achieved earlier than in a pure an inorganic cement based system due to early pore closure.
[0031] Said polyacrylic acid or salt thereof is an acid in the group that consists of PAA, Me(I)-PAA, PAMA and Me(I)-PAMA, wherein
PAA=poly acrylic acid
PAMA=poly(acrylic-co-maleic acid)
Me(I)-PAMA=poly(acrylic-co-maleic acid) Me(I)-salt
Me(I)-PAA=poly acrylic acid Me(I)-salt
[0032] Me(I)=alkali metal ion, e.g. Na, K or Li
[0033] In one embodiment of the invention, at least a part or most preferred all of the reactive groups in the polycarboxylic based material bond to the CBC system.
[0034] The system may comprise one or more expansion compensating additives adapted to give the ceramic material dimensionally stable long-term attributes, as is described in WO 00/21489. Other additives and aspects of the system may follow that which is described in SE 463,493, SE 502,987, WO 00/21489, WO 01/76534, WO 01/76535, PCT/SE02/01480 and PCT/SE02/01481, the contents of which are incorporated herein by reference. For example, it is preferred at least for dental filling materials that the system comprises additives and/or is based on raw materials that contribute to translucency of the hydrated material.
[0035] According to one aspect of the invention the inert filler particles are composed of pre-hydrated chemically bonded ceramics of the same composition as the main binding phase. This improves the homogeneity of the microstructure and enhances the binding between reacting chemically bonded ceramics and the filler material.
[0036] According to another aspect of the present invention an additional system can be included to improve the closure of pores initially, namely by introducing a system that works independently of the pH, e.g. the semihydrate of CaSO 4, gypsum. And a further system to solidify the total system initially, the combination of phosphoric acid and zinc oxide-forming Zn-phosphate. These phases will not contribute to the long-term properties but will enhance the initial pore closure and initial strength.
[0037] By using granules the w/c ratio (water/cement ratio) can be lower than for the loose powder. The flow-ability of the material is higher when it is granulated. The granules should preferably be of a size below 1 mm, more preferably below 0.5 mm and most preferably below 0.4 mm. The compaction density of the granule, the granule density should be above 35%, preferably above 50% most preferably above 60%.
[0038] By using such highly compacted small granules, the shaping of the material can take place in a subsequent step, without any remaining workability limitations of highly compacted bodies. A facilitated shaping in such a subsequent step, such as kneading, extrusion, tablet throwing, ultrasound etc., can be made while retaining a mobility in the system that has a high final degree of compaction, exceeding 35%, preferably exceeding 50%, even more preferred exceeding 60%.
[0039] The principle is based on the fact that a small granule—after granulation of a pre-pressed, highly compacted body—contains several tenths of millions of contact points between particles in the same, which particles are in the micrometer magnitude. When these small granules are pressed together to form new bodies, new contact points arise, which new contact points are not of the same high degree of compaction. The lower degree of compaction in these new contact points results in an improved workability, while the total degree of compaction is only marginally lowered by the lower degree of compaction in the new contact points. This is due to the new contact points only constituting a very slight proportion of the total amount of contact points. Even if for example a thousand new contact points are formed, these contact surfaces will be less than per mille of the total contact surfaces, i.e. they have a very slight influence on the end density, which will be determined by the higher degree of compaction of the granules according to the present invention. Moreover, the contact zones between individual, packed granules will hardly be distinguishable from the other contact points, as the general hardening mechanism for systems according to the invention comprises dissolution of solid material by reaction with water, which leads to the formation of ions, a saturated solution and hydrate precipitation.
[0040] In a system in which the cement hydrates due to an added liquid, the new contact points will furthermore be filled by hardened phases, which means that the homogeneity increases after the hydration/hardening. By the final degree of compaction being increased in that way, a more dense end product will be obtained, which leads to an increased strength, a possibility to lower the amount of radio-opaque agents and an easier achieved translucency, at the same time as the workability of the product is very good.
[0041] According to one aspect of this embodiment, the granules preferably exhibit a degree of compaction above 60%, even more preferred above 65% and most preferred above 70%. Preferably, the granules have a mean size of at least 30 μm, preferably at least 50 μm and even more preferred at least 70 μm, but 250 μm at the most, preferably 200 μm at the most and even more preferred 150 μm at the most, while the powder particles in the granules have a maximal particle size less than 20 μm, preferably less than 10 μm. It should hereby be noted that it is only a very slight proportion of the powder particles that constitute particles having the maximal particle size. The particle size is measured by laser diffraction. The highly compacted granules are manufactured by the powdered material being compacted to the specified degree of compaction, by cold isostatic pressing, tablet pressing of thin layers, hydro-pulse technique or explosion compacting e.g., where after the material compacted accordingly is granulated, for example crushed or tom to granules of the specified size.
[0042] The system and material according to the invention have the advantages compared to systems/materials such as glass ionomer cements and pure Ca-aluminate based systems or monomer based filling materials, that it maintains its bioactivity, that it has improved initial strength and that it has long time stability regarding both dimensional aspects, strength and minimised deterioration. The viscosity of the material can be controlled within wide ranges, upon initial mixing of the powdered material and the hydration liquid, from moist granules to an injectable slurry. The material is unique in that it solidifies in at least two steps, i.e. by cross-linking of the organic acid or salt thereof with cat-ions from both the inorganic cement system and the added reactive glass, and by hydration of one or more systems.
EXAMPLE 1
[0043] Tests were performed to investigate the influence of amount of poly acid and the composition of the chemical bonded ceramic on the mechanical properties. The values are compared to commercial glass ionomer cement and amalgam.
Raw Materials Used
[0044] Calcium aluminate ((CaO) 3 (Al 2 O 3 ), (CaO)(Al 2 O 3 ), (CaO) 12 (Al 2 O 3 ) 7 ), calcium silicates (CaO)(SiO 2 , (2CaO)(SiO 2 ), (3CaO)(SiO 2 ), dental glass filler (Schott), poly acid (PAA=poly acrylic acid Mw=50,000, Na-PAMA=poly(acrylic-co-maleic acid) sodium salt Mw=50,000) and reactive glasses (Schott and experimental glass). Glass ionomer cement (Fuji II, GC-corp) and Amalgam (Dispersalloy, Dentsply).
Preparation of Material Used
[0045] Calcium aluminate was mixed with dental glass, reactive glass, poly acrylic acid and poly(acrylic-co-maleic acid) sodium salt. The calcium aluminate phases were synthesised via a sintering process, wherein first CaO and Al 2 O 3 were mixed to the desired composition and then sintered at elevated temperature for 6 hours. The formed calcium aluminate lumps were crushed and jet-milled to a mean grain size of 1.5 μm and a maximum grain size of 9 μm. The dental glass, calcium aluminate and poly acids were mixed with acetone and Si 3 N 4 marbles for 14 hours to obtain the desired homogeneity. The same procedure was used for the Formulation 8 using Ca silicates. Formulations were made according to (in wt. %):
[0000] Na- Inert Reactive PAMA PAA Formulation Calcium aluminate phase glass glass Mw 5000 Mw 50000 1 (CaO)(Al 2 O 3 ) 63.5 33.5 — 3 — 2 (CaO)(Al 2 O 3 ) 47 25 20 3 5 3 (CaO)(Al 2 O 3 ) 31 17 40 2 10 4 (CaO)(Al 2 O 3 ) 13 6 60 1 20 5 (CaO)(Al 2 O 3 )/(CaO) 12 (Al 2 O 3 ) 7 25 20 3 5 mineral mixture of 90/10 and 47 in total 6 (CaO)(Al 2 O 3 )/(CaO) 12 (Al 2 O 3 ) 7 17 40 2 10 mineral mixture of 50/50 and 31 in total 7 (CaO)(Al 2 O 3 )/(CaO) 12 (Al 2 O 3 ) 7 5* 42 — 7 mineral mixture of 50/50 and 46 in total 8 (CaO)(SiO 2 )/(2CaO)(SiO 2 )/ 5 42 — 7 (3CaO)(SiO 2 ) mineral mixture of 45/45/10 and 46 in total *= inert glass as fibers
The formulations were placed in 5 ml jars and wet with liquid and blended in a “Rotomix” (3M ESPE) for 15 seconds followed by centrifugation for 3 seconds. In addition 18 mM of LiCl was added to further increase the hydration speed. The liquid contents were controlled via
[0000]
w
c
c
+
P
A
A
reactive_glass
+
w
G
I
C
reactive_glass
[0000] with a w c /c=0.32 (refers to the inorganic cement-system), PAA/(reactive glass)=0.14 and w/(reactive glass)=0.37 (refers to the glass ionomer system).
Description of Tests
[0046] The diametral tensile strength was measured for the six formulations, the amalgam and the glass ionomer cement. The strength was measured after 15 min, 60 min, 4 hours and 24 hours. All samples were stored in phosphate buffer solution (pH 7.4) before measurement of DTS. The pH was measured by soaking a defined amount of material in distilled water (material/water ⅓ by volume) for the same time periods as the DTS-measurements. All storages were at 37° C.
Results
[0047] The results of the tests were:
[0000]
15 min
60 min
4 hours
24 hours
Material
(MPa)/pH
(MPa)/pH
(MPa)/pH
(MPa)/pH
Formulation 1
1.5/8
6.2/10
8.3/11
20.1/11.1
Formulation 2
2.1/3.2
8.5/6
11.1/8
26.8/10.9
Formulation 3
4.3/3
9.1/5.7
14.7/7.3
26.7/10.5
Formulation 4
8.2/2.4
10.4/4.2
12.2/6.3
14/7
Formulation 5
3.1/3
8.7/6.6
12.4/9
29/11.3
Formulation 6
5.5/2.1
10.3/5.7
15.4/7.6
27.7/10.9
Formulation 7
9.0/7.2
11.3/10.5
15.5/10.5
28.5/10.5
Formulation 8
6.0/12.2
7.1/12.4
10.9/12.1
21.7/11.8
Fuji II
10.1/2
12.3/2.5
11.2/3.1
11.1/4
Dispersalloy
2.1/n.a.
9.1/n.a.
14.2/n.a.
29.3/n.a.
[0048] By adding PAA and reactive glass to the calcium aluminate system an increased initial strength can be achieved. Also, by adding (CaO) 12 (Al 2 O 3 ) 7 the reaction speed is increased and thus also the initial strength. The increase in pH over time for the formulations with calcium aluminate shows that the hydration reaction is similar to the pure calcium aluminate system.
EXAMPLE 2
[0049] A series of tests was performed to investigate the influence of poly acid on the acid erosion resistance. The values are compared to commercial glass ionomer cement (Fuji II) and to commercial calcium aluminate based dental material (DoxaDent, Doxa AB).
Raw Materials Used
[0050] Calcium aluminate (CaO)(Al 2 O 3 ), dental glass filler (Schott), Na-PAMA=poly(acrylic-co-maleic acid) sodium salt, poly acrylic acid Mw 50000, reactive glass.
Description of Tests
[0000]
Test a) to c) investigated:
a) the acid erosion of Fuji II b) the acid erosion of DoxaDent c) as formulation 3 described in Example 1. d) as formulation 7 described in Example 1.
[0056] The calcium aluminate phases were synthesised via a sintering process where first CaO and Al 2 O 3 were mixed to the desired composition and then sintered at elevated temperature for 6 hours. The formed calcium aluminate lumps were crushed and jet-milled to a mean grain size of 3 μm and a maximum grain size of 9 μm. The dental glass, reactive glass, calcium aluminate and poly acids were mixed with acetone and Si 3 N 4 marbles for 14 hours to obtain the desired homogeneity. The samples in the tests c) and d) were blended to the desired water to cement ratio in 5 ml jars and rotated at 500 rpm for 15 seconds. DoxaDent and Fuji II samples were made according to the manufactures instructions. The acid erosion was measured according to ISO-9917.
[0057] The results showed that the tests in b) and c) and d) exhibited an acid erosion of below 0.01 mm/h (below the detection limit) whereas the glass ionomer cement showed a acid erosion of 0.1 mm/h. Thus the results show that addition of poly acid to calcium aluminate does not reduce its acid resistance.
EXAMPLE 3
[0058] A series of tests was performed to investigate the possible in vitro bioactivity of the calcium based cement material, the glass ionomer cement and the combination of the two. Bioactivity is defined herein as the ability to form apatite on the surface in contact with body fluids.
Preparation of Materials Used
[0059] Calcium aluminate was mixed with dental glass, reactive glass, poly acrylic acid and poly(acrylic-co-maleic acid) sodium salt. The calcium aluminate phases were synthesised via a sintering process where first CaO and Al 2 O 3 was mixed to the desired composition and then sintered at elevated temperature for 6 hours. The formed calcium aluminate lumps were crushed and jet-milled to a mean grain size of 2.5 μm and a maximum grain size of 9 μm. The dental glass, calcium aluminate and poly acids were mixed with acetone and Si 3 N 4 marbles for 14 hours to obtain the desired homogeneity. The same procedure was used for the Formulation 8 using Ca silicates. Formulations were made according to (in wt. %):
[0000] Inert Reactive Na-PAMA PAA Formulation Calcium aluminate phase glass glass Mw 5000 Mw 50000 1 (CaO)(Al 2 O 3 ) 63.5 33.5 — 3 — 2 (CaO)(Al 2 O 3 ) 47 25 20 3 5 3 (CaO)(Al 2 O 3 ) 31 17 40 2 10 4 (CaO)(Al 2 O 3 ) 13 6 60 1 20 5 (CaO)(Al 2 O 3 )/(CaO) 12 (Al 2 O 3 ) 7 25 20 3 5 mineral mixture of 90/10 and 47 in total 6 (CaO)(Al 2 O 3 )/(CaO) 12 (Al 2 O 3 ) 7 17 40 2 10 mineral mixture of 50/50 and 31 in total 7 (CaO)(Al 2 O 3 )/(CaO) 12 (Al 2 O 3 ) 7 5* 42 — 7 mineral mixture of 50/50 and 46 in total 8 (CaO)(SiO)/(2CaO)(SiO 2 )/ 5 42 — 7 (3CaO)(SiO 2 ) mineral mixture of 45/45/10 and 46 in total *inert glass as glass fibers
0.5 grams of each the formulation were placed in 5 ml jars and wet with liquid and blended in a mixer by 3M/ESPE for 15 seconds followed by centrifugation for 3 seconds. In addition 18 mM of LiCl was added to further increase the hydration speed. The liquids composition were controlled via
[0000]
w
c
c
+
P
A
A
reactive_glass
+
w
G
I
C
reactive_glass
[0000] with a w c /c=0.32 (refers to the CBC-system), PAA/(reactive glass)=0.14 and w/(reactive glass)=0.37 (refers to the glass ionomer system). For comparison samples of GIC were also made.
Description of Tests
[0060] The bioactivity was studied by soaking a defined amount of material in simulated body fluid (SBF) (material/SBF ⅓ by volume) for time periods of 1 day, 7 days and 21 days at 37° C. After storage the samples were removed from the SBF, rinsed in distilled water and dried at 37° C. for 48 hours. The surface composition of the formulations was studied with thin film X-ray diffraction (1° angle) and SEM combined with EDX. For each formulation and time period 5 samples were analysed. For SEM the presence of Ca and P on the surface with a ratio 1.67 indicates formation of apatite. In XRD the peaks according to the powder diffraction file for apatite must comply with the pattern from the sample.
Results
[0061] The results from the analysis can be seen in the Table below. All formulations with calcium based cements formed apatite on the surface after 21 days. The formulations with low amounts of calcium aluminate did not form the apatite layer as quick as the formulations with much calcium aluminate, which all had apatite on the surface after 1 day. The GIC material did not form apatite on the surface. Thus the combined material can be considered bioactive.
[0000]
TABLE
Results from the bioactivity tests.
1 day
7 days
21 days
Material
XRD/SEM
XRD/SEM
XRD/SEM
Formulation 1
Apatite
Apatite
Apatite
Formulation 2
Apatite
Apatite
Apatite
Formulation 3
Apatite
Apatite
Apatite
Formulation 4
—
—
Apatite
Formulation 5
Apatite
Apatite
Apatite
Formulation 6
Apatite
Apatite
Apatite
Formulation 7
Apatite
Apatite
Apatite
Formulation 8
Apatite
Apatite
Apatite
Fuji II
—
—
—
[0062] The invention is not limited to the embodiments described herein, but can be varied within the scope of the claims. | A two-step system for chemically bonded ceramic (CBC) materials, and especially a dental filling material or an implant material. The system includes an initial working part-system to provide for improved early-age properties and a second main system to provide for improved end-product properties including bioactivity. The systems interact chemically. The invention also relates to the powdered materials and the hydration liquid, respectively, as well as the formed ceramic material. | 2 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation application of U.S. application Ser. No. 10/362,396 filed Jul. 16, 2003, now pending, which is a national stage entry of International Application No. PCT/EP01/08148 filed on Jul. 14, 2001, which claims the benefit of German Application No. DE 100 41 757.4-45 filed on Aug. 25, 2000, the entire contents of all of which are incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention concerns the production of glass in general from waste glass or glass batches. The three essential stations of the production process comprise melting, then refining and finally homogenizing.
[0004] 2. Description of Related Art
[0005] The production of high-value special glasses requires the process step of refining after melting, in order to remove the residual bubbles from the melt. The prior art comprises the refining of glasses by addition of refining agents such as redox refining agents or evaporating refining agents. One speaks here of chemical refining, since the release of gases form the melt is utilized in order to inflate small bubbles that are present and thus to facilitate the rise of these bubbles.
[0006] Along with the methods of chemical refining, alternatively or additionally, physical effects are utilized, as described in the literature, for expelling bubbles and thus for refining, such as, for example, centrifugal force (U.S. Pat. No. 3,893,836) or the reduction of the bath depth and thus the rise of bubbles to the surface of the melt is facilitated (DE 197 10 351 C1).
[0007] It is known that refining is promoted by increasing the temperature of the melt. However, when refractory material is used for the refining tank, limits are imposed. If ceramics with high a zirconium content are used, then temperatures of a maximum 16,500° C. can be produced.
[0008] It is known also to conduct refining in an apparatus that operates according to the so-called skull pot principle. See EP 0 528,025 B1. Such a device comprises a crucible, the walls of which are formed from a ring or collar of metal pipes, which can be connected to a cooling medium, with slots between the metal pipes adjacent to one another. The device also contains an induction coil, which surrounds the walls of the crucible and by means of which high-frequency energy can be coupled into the contents of the crucible. This direct heating of the glass melt by means of irradiation of high-frequency energy is conducted at a power of 10 kHz to 5 MHz.
[0009] Such a crucible permits essentially higher temperatures than a vessel made of refractory material. The advantage of high-temperature refining in comparison to all other physical refining processes is that it is very effective and rapid due to the high temperatures. The processes take place clearly more rapidly at high temperatures, so that very small, rapid aggregate modules can be prepared for the process of refining.
[0010] DE 2,033,074A describes an arrangement for the continuous melting and refining of glass. A refining device is provided therein, which operates according to the skull pot principle. The melt from the bottom region of the melting vessel reaches the refining vessel via a connection channel. It enters in the bottom region of the latter. The glass flow in the refining vessel thus rises upward from the bottom. This has the advantage that the flow has the same direction as the lifting force of the bubbles. The bubbles to be removed reach the hot surface of the melt and are discharged from the latter.
[0011] A disadvantage of this embodiment consists of the fact that the connection channel between the melting-down basin and the high-frequency refining device is subject to intense wear and tear due to the high flow velocities.
BRIEF SUMMARY OF THE INVENTION
[0012] The object of the invention is to develop a system in which the good refining results remain, based on an upward flow of the glass melt, but in which also the melt remains hot at the surface in the region where the bubbles are discharged, so that all bubbles can burst at the surface, and in which the problematic connection channel between the melting vat and the refining device can be omitted.
[0013] The inventor has recognized the following: If the inlet as well as the outlet of the high-frequency crucible is arranged in the upper region and in fact in such a way that the two of these lie opposite one another, then a very good and effective refining results. One would have expected that with such a structure, an essential part of the melt would be unheated and unrefined and led along directly to the outlet in the short circuit from the inlet at the surface. However, this is not the case. Rather, a defined flow is set up based on the differences in density in different melt regions. If the expansion coefficient of the melt is sufficiently high and the heating of the melt in the crucible is assured appropriately, the laterally introduced cold glass does not directly reach the crucible outlet via short-circuit currents, but is first pulled to the bottom of the crucible and from here is led to the surface and to the outlet via convection rollers according to circular movements of variable length.
[0014] The inlet and outlet should essentially lie diametrically opposite each other. This is not absolutely necessary, however; certain deviations are admissible. Also, the crucible should be dimensioned correctly, but this is an optimizing problem, which can be solved by the person of average skill in the art.
[0015] The connection channel between the melting vat and the refining crucible, which is known from the prior art, will be avoided. Instead of this, the melt can overflow from the melting vat into an open channel to the refining crucible.
[0016] It may be appropriate to configure the refining crucible according to DE 2,033,074 A. The crucible comprises a lower part of relatively small diameter, and an upper part of relatively large diameter.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0017] The invention is explained in more detail on the basis of the drawing. The following are shown individually therein:
[0018] FIG. 1 shows a set-up for the production of glass.
[0019] FIG. 2 shows a refining crucible according to the invention in a vertical section.
[0020] FIG. 3 shows another embodiment of a set-up for the production of glass.
[0021] FIG. 4 shows a cooled bridge barrier in the skull crucible, in schematic representation.
[0022] FIG. 5 illustrates the integration of the bridge barrier into a skull crucible.
[0023] FIG. 6 shows a set-up for the melting of glass with two refining stations.
DETAILED DESCRIPTION OF THE INVENTION
[0024] The set-up shown in FIG. 1 comprises a melting-down basin 1 with an introduction device 1 . 1 . The glass batch 1 . 2 which has been introduced is retained by a bridge barrier 1 . 3 to keep it from flowing further to the stations connected downstream.
[0025] An overflow channel 2 is connected to the melting-down basin 1 . This is open at the top. The crude melt reaches a refining device 3 via the overflow channel 2 .
[0026] This refining device comprises a skull crucible and also a high-frequency coil, which is not shown here. The actual refining is conducted here at temperatures of 1750 to 3,000° C., depending on the glass synthesized and the requirements for glass quality.
[0027] After the refining, the melt is free of bubbles. It reaches a homogenizing device 5 , which in turn comprises a stirring crucible and a stirrer, via a conventionally heated channel system 4 .
[0028] The structure of the skull crucible can be recognized in detail in FIG. 2 . This involves a so-called mushroom skull crucible according to DE 2,033,074 A. The skull crucible has a lower crucible part 3 . 1 of a relatively small diameter, and in addition an upper crucible part of a relatively large diameter. The upper crucible part also contains the inlet 3 . 2 and the outlet 3 . 3 for the melt. The arrows indicate the flow of the melt. As is seen, the cold glass introduced laterally through the inlet 3 . 2 first falls downward to the bottom of the crucible 3 . 4 , then rises again upward in order to once more flow downward and then upward again. As is seen, the lower part 3 . 1 of the skull crucible is surrounded by a high-frequency coil 3 . 5 .
[0029] The set-up shown in FIG. 3 is the refining device 3 equipped with an additional, cooled bridge barrier 3 . 6 . This has the following task: If the glass arriving in the skull refining aggregate is very foamy or the expansion coefficient of the melt as a function of temperature is very small, then the danger exists that a small portion of the melt is drawn over the surface. This can be prevented either by a clear increase in the temperature difference between the melt flowing in and the melt in the core of the crucible in the skull crucible module or by incorporating the bridge barrier 3 . 6 .
[0030] The bridge barrier 3 . 6 may be comprised of either a gas-cooled or liquid-cooled ceramic material or of a water-cooled metal material. Modifications of cooled metal components lined with ceramics are also conceivable. If the bridge barrier has metal components, which lie above the surface of the melt and come into contact with the burner atmosphere, then it may be helpful to coat the bridge barrier with a thin layer of Teflon (<150μ) in order to prevent a corrosion of the metal surface due to the aggressive burner atmosphere. The bridge barrier 3 . 6 can either be positioned centrally in the refining module or can be laterally displaced to inlet 3 . 2 . The latter modification has the advantage that the hot zone where the bubbles rise can be made as large as possible. If the bridge barrier is constructed of metal material, then it should be electrically connected to the metal skull crucible, so that no induced voltages build up between the metal corset and the barrier, since these can lead to arcing and thus to the disruption of the metal wall. If an electrical connection cannot be produced, then all components must be operated in an electrically free-floating manner—i.e., not grounded. This is particularly possible if the melt tends toward intense crystallization, since In this case a stable puncture-proof intermediate layer is formed, which reliably stops the arcing.
[0031] An example of embodiment of such a bridge barrier 3 . 6 is shown in FIG. 4 . The incorporation of such a barrier 3 . 6 can be seen in FIG. 5 . Here, the barrier 3 . 6 is positioned below the surface of the melt. This has the advantage that there are no cold metal components in the upper furnace space. The condensation of burner off-gases is particularly problematical on cold components. It is a disadvantage in this type of assembly that large fluctuations in the glass level cannot be allowed, since in order to assure that no liquid melt flows over the barrier, the immersion depth should be a maximum of 1 cm below the surface of the melt.
[0032] A barrier assembly can be made possible with the edge of the barrier above the upper edge of the glass bath by lining the metal barrier either with Teflon or ceramic materials or by raising the glass level first higher at the beginning of the process—and in fact raising it over the upper edge of the barrier—and then again lowering the glass level to the normal level in operation. In this case, a glazing of the barrier is achieved, which protects the barrier from attacks due to burner off-gases. In addition to the embodiment of the barrier that is shown here, simpler embodiments, for example, a simple ceramic stone barrier or even a cooled metal rod which runs crosswise over the crucible is conceivable.
[0033] An electrical connection 3 . 7 of the crucible 3 with the barrier 3 . 6 as well as a crucible short-circuit ring 3 . 8 can be seen in detail in FIG. 5 .
[0034] A cascade refining is provided In the set-up shown in FIG. 6 . The introduced glass batch 6 as well as a bridge barrier 7 can also be recognized again here.
[0035] Several refining modules are connected one after the other and they connect with one another simply in the upper region. The connection sites can be heated conventionally, for example, with burners. In this case, complicated connection channels that are sensitive to disruption and consume a great deal of energy can be omitted. An example with two refining modules connected one after the other is shown in FIG. 6 . Of course, any number of refining modules connected one after the other is conceivable.
[0036] With respect to geometry—particularly diameter—, HF-frequency and HF voltage are adapted to the conductivity of the glass to be melted in each case. If different types of glass with clearly different electrical conductivities are to be melted in the same vat and are to be refined by means of HF heating, then this is not possible without retrofitting measures (connection of another generator with adapted frequency region, connection of an adapted coil, possible change of the melting diameter, adaptation of the capacities in the HF generator). Of course, as in FIG. 6 , two or more aggregates can be connected one after the other, and thus each individual module can be adapted to different electrical melting properties. The HF energy is only turned on in the HF refining module adapted to the respective melt, whereas the other modules are not heated with HF energy, but only with conventional energy—such as, for example, burners in the upper furnace space. The melt flows over the modules that are not turned on and is drawn into and heated only in the HF-heated module. In order to configure the exchange of glass in such an aggregate in a simpler and quicker manner, it is helpful if each module has an additional bottom outlet 9 , which is opened for a short time in the glass exchange phase. Such a bottom outlet can also be of use in the case of the simple structure with only one HF-module—particularly if exchanges of glass in the vat are considered—but also if bottom residues should deposit thereon.
[0037] Another advantage of the invention is the very good “emergency running properties” of the set-up if there are disruptions in the HF range. If the high-frequency heating apparatus fails for any reason whatever, then there exists the danger of a freezing up of the continuous flow in the case of the continuous-flow crucible with introduction from below, whereby the glass flow is interrupted. The danger does not exist in principle in the present invention, since the glass flow can be assured in each case by utilizing the upper heat of the burner. | A device for the refining of a glass melt at high temperatures according to the skull pot principle is provided. The device includes a skull crucible having walls that are constructed from a plurality of pipes, a high-frequency coil for coupling electrical energy into the contents of the skull crucible, and an inlet and an outlet of the skull crucible being arranged in a melt surface region of the glass melt, wherein the inlet and the outlet are essentially arranged lying opposite one another. | 2 |
The present invention relates to wood pulp processing and specifically to an apparatus and method for the digester of a pulp mill. More specifically, the present invention relates to such a method and apparatus which permits greater flexibility in the type of wood chips processed and the composition of the liquor used in the digester by providing a system to alleviate the scaling and clogging that would otherwise result on the strainers of the digester when certain compositions of the liquor are used with certain types of wood chips.
BACKGROUND OF THE INVENTION
In the pulp processing industry, wood chips are introduced into a digester where these are treated under high pressure and temperature by a liquor that is introduced into the digester to break down the lignin and hemicellulois content of the wood fibers, leaving only the cellulose. During the digesting process, the liquor is drawn out of the digester at various locations and recirculated to the digester. So that the wood chips remain in the digester, it is necessary that the liquor that is being removed passes through a strainer which has slot like openings that prevent the passing of wood chips but permit the passage of the liquor therethrough.
If the strainers in the digester become clogged, then it is commonly necessary to shut down the digester and remove the scaling from the strainers. Such a shutdown can be extremely costly, and make it economically unfeasible to operate the pulp mill in that manner. Quite commonly this problem is alleviated by formulating the composition of the liquor so that certain components of the liquor will prevent the formation of the scaling on the strainers.
This formulation will depend to some extent on the species of the wood from which the chips are made. For example, with soft wood, the scaling would be more of a problem. An example of this is in a digester which uses alcohol (either ethyl or methyl alcohol) as one of the major components of the liquor. If soft wood is being treated in the digester, there is more of a tendency for scaling to form. However, the addition of sodium hydroxide to the liquor composition substantially alleviates the scaling problem.
The further treatment of the black liquor resulting from the digester process is also an important part of the operation of a pulp mill. In order to operate a pulp mill economically, it is generally necessary to process or utilize the black liquor in some manner to extract value therefrom. This can be done in various ways. Generally, the black liquor goes to an evaporator where a substantial portion of the water content is removed. Then the residue from the black liquor can be burned to generate heat energy which is utilized in other parts of the pulp mill and to recover the non-organic chemicals in the liquor for recirculation in the pulping process. Alternatively, the residue remaining in the black liquor after the evaporation can be utilized in other applications, such as producing adhesive for particle board or animal food pelletizing, etc.
SUMMARY OF THE INVENTION
In view of the foregoing, it is the principle object of the present invention to provide method and apparatus for a digester in a pulp processing system which is able to alleviate the problem of clogging and the formation of scaling on the strainers of the digesters to allow more flexibility in the formulation of the composition of the digesting liquor. One specific advantage of the present invention can in some instances result in enabling the black liquor to be utilized in a manner which could be more profitable.
A specific application of the present invention is to be utilized in a digester using ethyl and/or methyl alcohol as the main active ingredient of the digesting liquor, while processing wood chips (such as wood chips from soft woods) which are prone to cause clogging of the strainers.
Briefly, this is accomplished by cooking liquor under heat and pressure during an initial cooking phase, and then extracting at least a portion of the liquor and introducing fresh liquor to adjust pH level of the cooking liquor, after which a second phase of cooking of the wood chip material is accomplished.
The apparatus of the present invention comprises a containing structure defining a processing chamber, and having an inlet means to receive wood chip material and a cooking liquor into the chamber, and an outlet means to discharge digested wood material. The containing structure defines the cooking zone within which the liquor reacts with the wood chip material during a digesting cycle.
There is strainer means located in the containing structure to permit an outflow of liquor from the chamber, while retaining the wood chip material in the chamber. There is also means to extract a portion of the digesting liquor from the processing chamber through at least a portion of the strainer means at an intermediate part of the digesting cycle.
There is also means to introduce at least a portion of relatively fresh liquid into the chamber to replace at least part of the digesting liquor removed so as to adjust pH level of the digesting liquor in the chamber to inhibit scaling and/or clogging of the strainer means.
In the preferred form, the pulp digester apparatus is a continuous digester and defines a cooking zone having an inflow region, an outflow region, and an intermediate region between the inflow region and the outflow region, with the portion of the digesting liquor being extracted from said intermediate region.
There is also in the preferred form means to recirculate at least a portion of the digesting liquor back to the digesting zone and selectively direct a portion of the digesting liquor extracted to another location for further processing. Further, in the preferred form, there is a second means to extract a second portion of digesting liquor form the digesting chamber at a location downstream of the intermediate processing region, and this is accomplished through another portion of said strainer means.
In the method of the present invention, a digesting apparatus is provided as described above. The wood chip material and the cooking liquor are directed into the chamber and the initial cooking of the wood chip material under heat and pressure is accomplished during an initial cooking phase. Then at least a portion of the digesting liquor is extracted from the processing chamber subsequent to the initial cooking phase through at least a portion of the strainer means, while retaining the wood chip material in the chamber.
Then there is introduced into the chamber a portion of relatively fresh liquor to replace at least part of the digesting liquor removed so as to adjust the pH level of the digesting liquor to a level to inhibit scaling and/or clogging of the strainer means.
Other features of the present invention will become from the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a somewhat schematic drawing illustrating a digesting portion of a prior art pulp processing system in which the present invention can be effectively utilized;
FIG. 2 is a semi-schematic view showing a pulp digester, such as that shown in FIG. 1, incorporating the teaching of the present invention in a pulp processing system similar to that shown in FIG. 1;
DESCRIPTION OF THE PREFERRED EMBODIMENT
It is believed that a clearer understanding of the present invention will be obtained by first reviewing the digesting portion of a typical pulp mill for which the present invention is particularly adapted. With reference to FIG. 1, the wood chips are first subjected to magnetic separation of tramp iron and screening at location 1, and then directed into a surge bin of a hopper indicated at 2. From the hopper, the chips flow into a chip meter 3 which controls the rate of flow of the chips which then pass into a low pressure feeder 4.
The feeder 4 directs the chips into a steaming vessel 5 that is kept at between 15 to 20 PSI where the chips are pre-steamed. The chips are then directed from the steaming vessel 5 into the chip chute 6, from which the chips move to a high pressure feeder 7. The chips are flushed into the feeder by means of a chip chute circulating pump 8. As seen in FIG. 1, the flow from the pump 8 into the chip chute 6 and to the feeder 7 is in a counterclockwise direction. Liquor level of the chip chute 6 is controlled by the level tank 9. The wood chips mixed with a certain amount of liquor are then moved from the feeder 7 through a line 11 into a top strainer 12 to the top of the digester 14. A high pressure pump 10 introduces the cooking liquor to the digester, as well as the excess liquor from the chip chute level tank 9. The volume of the cooking liquor can be controlled by a magnetic flow meter.
In general, the digester pressure is controlled so as to be at about 200 PSI. The chips and the cooking liquor gradually move downwardly in the digester, first passing into an upper impregnation zone I and then to the heating zone II.
The temperature is raised in two steps by two cooking circulating systems, which comprise extraction strainers, pumps and central circulating chambers. Three heaters 13 are shown. After heating, the chips and liquor pass downwardly through the cooking zone III of the digester. As the chips then pass into the lower washing zone IV of the digester, extracted wash liquor is circulated through the chips to provide a quench of the cooking reaction. The chips continue to pass downwardly in the washing zone IV, then to be discharged. The entire sequence is arranged so that the duration of the digesting process is about one and one half to four hours.
Wash liquor from a subsequent filter tank or fresh hot water is pumped into the bottom of the digester and flows upwardly countercurrently to the chip flow. Elevated temperatures of 125° to 135° C. are controlled in the diffusion zone by an auxiliary wash liquor circulation and heater system.
At various locations in the digester, the liquor is recirculated to an upper location. A portion of the liquor that is extracted between zone III and zone IV is directed to a flash tank 17, and thence to flash heat evaporators. The pulp that is extracted from the bottom of the digester is directed to a blow unit 16 which has a pressure reducing function, and then further directed to a brown stock washer or to some other location for further processing. Eventually the black liquor developed during the digesting process is directed to an evaporator 19, and then for further processing as indicated schematically at 20.
Since the section of the wood pulp processing system shown in FIG. 1 (and also the entire pulp processing operation which would be compatible with the digesting section shown in FIG. 1) are well known in the prior art, these will not be described in detail any further. It is to be understood that to the extent that the novel components of the present invention cooperate advantageously with the other components or sections with the entire pulp processing operation, such components are deemed to be part of the disclosure of the present invention. For example, the present invention can result in an advantageous further use of the components derived from the black liquor, and as will be disclosed more fully later herein, this may permit the black liquor to be used in a manner that the lignin and other components derived from the wood fiber can advantageously be used for example, as a glue, binder, or constituent of other products such as panels, animal feed, etc.
In the preferred embodiment of the present invention, the active ingredient in the white liquor that is directed into the digester 102 is alcohol (desirably ethyl alcohol, methyl alcohol, or a combination of the two). The use of alcohol as the active ingredient has a number of desirable features, a significant one of which is that it alleviates substantial pollution problems that are inherent in other pulp digesting processes. Also the alcohol itself can more readily be recovered in a gaseous state and condensed, to be then redirected back through the system.
However, for some types of wood products (particularly soft wood) if alcohol is used alone as the digesting medium, then there is a tendency for the black liquor to form scaling on the outlet screens or strainers. If this problem is not alleviated in some manner, after possibly a couple weeks or so of operation, the screens become clogged sufficiently so that the digester has to be shut down, emptied, and the screens cleaned. Obviously, the cost of this is very substantial, and thus in many instances makes the use of alcohol as the main digesting medium impractical.
A method of alleviating this is to add some other ingredient to the processing liquor to counteract this scaling. In the prior art, this can be done by adding sodium hydroxide in a sufficient amount to prevent the scaling. The sodium hydroxide then remains as part of the solids in the black liquor. The sodium hydroxide is sufficiently expensive so that to operate the mill in an economical fashion, sodium hydroxide is often recovered from the black liquor and reused in the system.
Then there is the problem of separating the sodium hydroxide from the other components of the black liquor (mainly the lignin). One manner of accomplishing this is simply to burn the lignin and use the heat in the operation of the pulp mill. Another alternative is simply to use the lignin for some commercial purpose, but the presence of the sodium hydroxide limits the uses for such lignin.
The present invention is intended to alleviate this problem.
FIG. 2 shows the digester system 100 of the present invention, comprising a digester 102 which is of the general type as the prior art digester shown at 14 in FIG. 1. This digester 102 comprises a vertically aligned containing structure 104, also called a tower, having an upper end 106 into which wood pulp is directed through an intake opening schematically shown at 108, and into which processing liquor is introduced.
The digester 100 has four extraction locations, namely an upper extraction location 112, an intermediate extraction 114, a lower extraction location 116, and a lowermost extraction location 117. Also, the digester 100 has four processing zones, namely an upper impregnating zone 118, located above the first upper extraction zone 112, an initial delignification zone 120 positioned between the upper extraction location 112 and the intermediate extraction location 114, a final cooking zone 122 located between the extraction locations 114 and 116, and a lowermost high heat washing zone 124 located below the third lower extraction location 116.
At the upper extraction zone 112 there are two vertically spaced sets of screens 126 through which the liquid (i.e. liquor) that has moved with the pulp downwardly through the impregnation zone 118 is drawn by a pump 128. The pump directs this liquor through a first heat exchanger 130 and thence upwardly into an inlet 132 to flow downwardly through a outermost pipe 134 positioned vertically in the center of the upper part of the digester 102. The exit end of the pipe 134 is indicated at 136, which is at the location of the first extraction location 112.
Thus, it can be recognized that the liquid extracted at 112 is moved by the pump through the heat exchanger to raise its temperature, and then back into the digester to flow into and through the pulp and thence be recirculated again through the pipe 128. The mixture of liquor and pulp that flows downwardly from the upper extraction location 112 goes through an initial cooking or delignification stage, where a substantial portion of the lignin in the pulp is acted upon by the white liquor to cause a substantial portion of the lignin and other organic products to be dissolved in the liquor.
Then when the mixture of pulp and liquor flowing downwardly from the upper extraction location 112 reaches the second extraction location 114, a portion of the black liquor is extracted through the two sets of screens 138 at the intermediate extraction location 114 by the action of a pump 140. The pump directs the extracted liquor through another heat exchanger 142, and the liquor is directed by valves 141a and 141b in either or both of two directions.
First a portion of the liquor flowing from the heat exchanger 142 is recirculated through a line 144 and into an inlet 146 to flow downwardly through another centrally located pipe 148 positioned concentrically within the outer pipe 142, with the flow from this second pipe 148 exiting at 150 in the digester. This recirculation through the heat exchanger 142 is simply to add heat and thus maintain the temperature within the digester 102 at the appropriate level.
A second portion of the liquor extracted at the intermediate location 114 is directed to a flash tank 152. A portion of the alcohol and water from the liquor is extracted at 154 and is directed to a condenser to be reused in the system. The remaining liquor, with lignin therein and also some water and alcohol is directed by a pump 156 to an evaporator, indicated schematically at 157. At the evaporator there is alcohol and lignin recovery.
At this point, it is important to note that additional white liquor is introduced into the line 158 as clean liquor, so that when it combines with the liquor recirculated in the line 144 (which liquor has already reacted with the wood chips so as to have lignin and other material dissolved therein), the resulting mixture that flows further downwardly from the extraction zone 114 has been diluted and has a lower concentration of lignin and other organic material from the wood pulp. The importance of this will be discussed further later in this text.
Then the mixture of liquor and wood pulp that flows from the intermediate extraction location 114 downwardly through the zone 122 is further delignified. A substantial portion of this liquor is extracted at the lower extraction zone 116 in two directions. First, a portion of this liquor is drawn out by the pump 160 to flow upwardly through line 162 to an intake opening 163, and thence into a central tube 164 to exit at a lower location 166.
A second portion of this liquor at the lower extraction zone 116 is directed into a flash tank 168, with the alcohol and water exiting at 170 from the flash tank to be directed to a location for recovery and recirculation back into the system. The liquor from the flash tank 168 is directed by a pump 172 to the evaporator where the lignin is recovered and remaining alcohol is evaporated and recirculated back through the system.
At the lowermost extraction location 117 the liquor is recirculated through the line 173, to a heat exchanger 174, to an inlet 175, down a central pipe 176 and out at 177.
Wash water is directed through the line 178 into the lowermost section 179 of the digester 102 to mix with the wood chips that have been processed as these digested wood chips flow downwardly to be discharged at 110. Also, dilution water is directed through the line 180 into the exit area for the pulp to be added to the pulp that is then directed to a location for further processing, presumably a brownstock washer.
A significant features of the present invention is that the liquor in the digester is extracted at two different locations to be directed to the evaporator. In the present embodiment shown herein, the liquor is extracted at 114 between the initial delignifying zone 120 and the final cooking zone 122 further below. Then the rest of the black liquor is extracted at the third extracting location 116 below the final cooking zone.
The white liquor that is initially introduced through the inlet 108 at the very top of the digester is substantially pure white liquor, free from organic contaminates (e.g. lignin and other organic materials from the wood chips). Also, the lignin which is introduced in the line 158 to enter into the pulp liquor mixture at the second extraction zone 114 is also substantially pure white liquor. When the white liquor is first introduced into the wood chips it has a pH value of approximately 6.5. However, as the digesting process continues and the white liquor reacts with the organic material in the wood chips, this pH lowers. At a certain pH level (which is below 6.5, and somewhat higher than a pH of 3.5 to 4.0), the lignin (and possibly other organic material) tends to form into a sticky material which then forms as scaling on the inlet portion of the screens. This is alleviated in the present invention as follows.
The digesting process is controlled so that the liquor in the digester has not reached a sufficiently low pH to cause any appreciable amount of scaling when it arrives at the intermediate extraction location 114. At this intermediate extraction location 114, a portion of the liquor is removed by the pump 140. At the same time this is happening, the makeup clean white liquor is directed through the line 158 to exit at the pipe location 150 and mix with the wood chips and the liquor that were already in the digester at the extracting location 114. This fresh white liquor (having a pH value of about 6.5) raises the overall pH value of the liquor in the digester that now moves from the intermediate extraction location 114 down to the third extraction location 116. As the cooking process continues in the final cooking zone 122, the pH of the liquor again drops, but the process is controlled so that the pH value at the third extracting location 116 is still higher than that at which the scaling would occur on the outlet screens.
Various control techniques can be used to accomplish the ends of the present invention. A major control technique is that the liquor that flows from the heat exchanger 142 flows partly to the flash tank 152 and partly is recirculated back up through the inlet 146. If it is necessary to raise the pH at the extracting location 114 to a higher level, then a greater percentage of the liquor is directed to the flash tank 152, and more clean white liquor is added at 158. On the other hand, if it is not necessary to raise the pH level to that extent at the extraction location 114, a greater amount of the liquor can be recirculated through the line 144 and to the inlet 146, and the amount of fresh white liquor at 158 reduced.
As another facet of the present invention in addition to introducing fresh white liquor through the line 158 so as to be introduced at the location 150, other ingredients such as sodium hydroxide for raising the pH could be added at this location to serve some particular purpose.
It should also be noted that a significant amount of the lignin of the wood chip is located near the surface areas of the wood fibers, and the cooking that occurs in the initial delignification zone 120 causes a substantial percentage of the lignin to move out of the wood chips and be dissolved in the surrounding liquor. Thus, the recovery process that can be conducted with the liquor extracted from the flash tank 152 can provide a substantial amount of lignin.
When the chips pass further downwardly into the lower washing zone of the digester, the wash water is circulated through the chips in a manner conventional in the prior art, so this will not be described in detail herein.
It is evident that various modifications could be made in the present invention without departing from the basic teachings thereof. | A continuous pulp digesting apparatus where wood chips and a cooking liquor are directed into a first cooking zone, and a portion of the cooking liquor is extracted at an intermediate region downstream, of said first cooking zone. Fresh liquor is introduced into said intermediate region to adjust pH level to inhibit scaling and/or clogging of strainers in the digester, and further digesting is accomplished in a second cooking zone downstream of an intermediate region. Liquor is extracted through strainers at a lower location of said second cooking zone. | 3 |
This is a divisional of co-pending application Ser. No. 340,093 filed on Jan. 18, 1982 now U.S. Pat. No. 4,530,355.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to a compression screw assembly for applying a compressive force to a fractured bone and more specifically to a compression screw system including a lag screw, compression plate and compression screw which can be assembled, aligned and installed so that the lag screw is non-rotatably secured to the compression plate at the option of the surgeon.
2. Description of the Prior Art
Workers in the art have devised various compression screw systems for applying compression to a fractured bone. Generally, the systems include a lag screw which extends from the shaft of the bone through the fracture and is anchored in the head of the bone, a compression plate which is adapted to extend over at least a portion of the head of the lag screw and which is anchored to the shaft of the bone and a compression screw which extends from the compression plate to the lag screw to permit the application of a compressive force between the lag screw and the compression plate.
It is often desirable to assure that the lag screw is non-rotatably secured to the compression plate. Generally this is accomplished in a keyed system by providing the lag screw with a longitudinally directed keyway, and by providing the portion of the hollow barrel of the compression plate that extends over the head of the lag screw with a corresponding longitudinally directed key. The problem with these systems is that it is difficult to insert the compression plate over the lag screw so that the key and keyway are aligned properly because the lag screw is driven completely into the bone before the compression plate is inserted.
One method for alleviating the problem of aligning the lag screw and compression plate is to provide an extension attached to the head of the lag screw to permit the lag screw to be aligned with the plate barrel more easily. A second method is to recess the key of the barrel member away from the front end of the barrel member so that the alignment occurs in two distinct steps: first, the aperture of the barrel member of the compression plate is aligned with the lag screw; and second, the key of the barrel member is aligned with the keyway of the lag screw. In a still further method as shown in U.S. Pat. No. 4,095,591, a barrel guide means having an extension member extending outward of the bone and having a cross section similar to that of the lag screw is used so that the barrel member of the compression plate is aligned on the extension member before it is inserted into the fractured bone.
A major disadvantage of the compression screw systems mentioned above is that the surgeon must determine before the insertion of the lag screw whether to use a keyed system or a non-keyed system. If a keyed system is to be used, the lag screw and compression plate must have the keyway and key, respectively. If a non-keyed system is to be used, the lag screw must be able to freely rotate within the barrel of the compression plate.
Accordingly, there exists a need for a compression screw assembly wherein the parts are properly aligned and installed and thereafter the lag screw may be non-rotatably secured to the compression plate at the option of the surgeon.
SUMMARY OF THE INVENTION
The present invention provides a compression screw system including a lag screw, compression plate, compression screw and wrench assembly whereby the lag screw can be non-rotatably secured to the compression plate at the option of the surgeon. In addition, the compression screw system can be assembled and properly aligned prior to the insertion of the lag screw and compression plate into the bone.
The compression plate includes a hollow barrel member adapted to receive one end of the lag screw in at least one fixed orientation. The barrel member and lag screw are adapted to receive a member, preferably a clip, therebetween which, when inserted between the inner surface of the barrel member and the lag screw, prevents axial rotation of the lag screw with respect to the barrel member of the compression plate as in a keyed system. If the clip is not inserted with the barrel member of the compression plate the lag screw is able to freely rotate with respect to the compression plate as in a keyless system. The clip may be inserted within the barrel member of the compression plate at the option of the surgeon, and the decision of the surgeon may be reserved until the time when the clip is to be inserted.
Preferably, the wrench assembly includes a wrench for releasably engaging the lag screw into the bone, a member for holding the clip in place on the wrench prior to the insertion of the clip into the barrel member of the compression plate, a member for pushing the clip from the holding member into the barrel member of the compression plate between the inner surface of the barrel member and the lag screw, and a stabilizing rod for stabilizing the wrench assembly during the insertion of the lag screw and compression plate into the fractured bone.
In the preferred embodiment, the contour of the outer surfaces of the lag screw and the wrench are identical and are adapted so that the compression plate, clip, holding member and pushing member which have identical corresponding inner surface contours, can be inserted over the wrench and lag screw in the proper axial alignment. Preferably, the configurations are substantially round and include two flat portions, spaced 180° apart. Thus, the compression screw system can be aligned properly by aligning the flat portions of each member of the assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of the hip screw assembly as installed in a bone according to the present invention;
FIG. 2 is a sectional view of the compression plateof the assembly shown in FIG. 1;
FIG. 3 is a cross-sectional view of the compression plate shown in FIG. 2 taken along the line III--III;
FIG. 4 is a top plan view of the clip of the assembly shown in FIG. 1;
FIG. 5 is a side elevatonal view of the clip shown in FIG. 4;
FIG. 6 is a front elevational view of the clip shown in FIG. 4;
FIG. 7 is a rear elevational view of the clip shown in FIG. 4;
FIG. 8 is a top plan view of the clip holder for the clip shown in FIG. 4;
FIG. 9 is a side elevational view of the clip holder shown in FIG. 8;
FIG. 10 is a sectional view of the clip holder shown in FIG. 9 taken along the line X--X;
FIG. 11 is a rear elevational view of the clip holder shown in FIG. 8;
FIG. 12 is a cross-sectional view of the clip holder shown in FIG. 8 taken along the line XII--XII;
FIG. 13 is a side elevational view of the clip pusher for the clip shown in FIG. 4;
FIG. 14 is a cross-sectional view of the clip pusher shown in FIG. 13 taken along the line XIV--XIV;
FIG. 15 is a top plan view of the clip pusher shown in FIG. 13;
FIG. 16 is a front elevational view of the clip pusher as shown in FIG. 13;
FIG. 17 is a top sectional view of the shaft assembly showing the clip pusher, clip holder and clip assembled for installation;
FIG. 18 side sectional view of the shaft assembly as shown in FIG. 17;
FIG. 19 is a top view, in partial cutaway, of the hip screw assembly prior to the installation of the hip screw; and
FIG. 20 is a side view of the hip screw assembly shown in FIG. 19.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As shown in the Figures, compression screw assembly 10 consists of lag screw 20, compression plate 30, clip 40, wrench 50, stabilizing rod 60, clip holder 70, clip pusher 80 and compression screw 90.
Referring to FIGS. 1, 19 and 20, lag screw 20 includes a screw head 21 formed at one end of an elongated shaft 22 adapted to be installed into the shaft of the fractured bone, through the fracture, and anchored in the head of the fractured bone. Shaft 22 has a substantially circular cross section with flat portions 23 formed on either side of its outer edge. The second end of lag screw 20 includes drive portion 24. The cross section of drive portion 24 is smaller than that of the remainder of lag screw 20, and is preferably of a modified hexagonal configuration having six sides, one pair of opposing sides being of a different length than the other four sides. Drive portion 24 is adapted to fit within bore 54 of wrench 50 when compression screw assembly 10 is assembled. Lag screw 20 has a bore extending therethrough so that lag screw 20 can be inserted over a guide wire. The bore
of lag screw 20 contains a threaded portion 25 so that compression screw 90 can be threaded therein. In addition, the threaded portion formed at the lower end of stabilizing rod 60 is inserted within threaded portion 25 when compression screw assembly 10 is assembled.
As shown in FIGS. 1, 2, 3, 19 and 20 compression plate 30 includes barrel member 31 having a bore 32 extending therethrough of a size that permits bore 32 to accept the second end of lag screw 20 through end 33 of compression plate 30. The surface of bore 32 of barrel member 31 includes two flat portions 34 corresponding to flat portions 23 formed on the outer surface of lag screw 20 to permit inserton of clip 40 between flat portions 34 of barrel member 31 and flat portions 23 formed on the outer surface of lag screw 20. Each flat portion 34 includes an indentation 35 adapted to receive a tang 44 of clip 40. End 36 of bore 32 is adapted to receive compression screw 90 therein. Compression plate 30 also includes a member 37 for enabling compression plate 30 to be anchored to the shaft of the bone. Member 37 contains a plurality of holes 38 for the insertion of bone screws therethrough in order to anchor compression plate 30 to the shaft of the bone.
Clip 40, illustrated in FIGS. 1, 4 through 7, and 17 through 19, includes ring 41 having two flat portions 42. The inner surface of ring 41 is of a size that permits ring 41 to accept the second end of lag screw 20 and wrench 50; the outer edge of ring 41 is of a size adapted to permit insertion of clip 40 into bore 32 of barrel member 31 and bore 72 of clip holder 70 that clip 40 can be inserted within bore 32 of barrel member 31 between the outer edge of lag screw 20 and the inner edge of barrel member 31. Two elongated members 43 extend perpendicularly from flat portions 42 of ring 41. Members 43 include tangs 44 which are adapted to be received by indentations 35 formed in the inner surface of barrel 31 of compression plate 30 and grooves 75 of clip holder 70.
Referring to FIGS. 17 through 20, wrench 50 includes bore 51 adapted to receive stabilizing rod 60. As shown in FIG. 17, the shaft of wrench 50 includes a first portion or lower shaft 52 and a second portion or upper shaft 57. Lower shaft 52 has a smaller circumference than upper shaft 57. The lower shaft 52 of wrench 50 has an outer surface cross-section adapted to match that of lag screw 20 and includes flat portions 53 which correspond to flat portions 23 of lag screw 20. The end of lower shaft 52 contains drive portion 54, the inner surface of which has a shape corresponding to drive portion 24 of lag screw 20 and is adapted to accept drive portion 24. Depth markings 55, formed in the non-flat portions of wrench 50, are used as assembly 10 is installed in a bone shaft. Lower shaft 52 includes stops 56 formed on its outer surface at its upper end. Stops 56 are protruding portions of lower shaft 52 which are used to prevent premature separation of clip 40 and clip holder 70. The outer edge of upper shaft 57 of wrench 50 is of a larger circumference than that of lower shaft 52 and does not include any flat portions. Upper shaft 57 ends in a T-shaped handle 58. The plane passing through both arms of handle 58 is perpendicular to the plane passing through flat portions 53.
As illustrated in FIGS. 17 through 20, stabilizing rod 60 is inserted through bore 51 of wrench 50. Stabilizing rod 60 is cannulated so that compression screw system 10 can be threaded over a guide wire to aid in directing the insertion of lag screw 20 into the bone. Stabilizing rod 60 includes a threaded portion at its lower end which can be threaded within portion 25 of lag screw 20. Stabilizing rod 60 also includes knurled end 62.
Clip holder 70, shown in FIGS. 8 through 12 and 17 through 20, includes an upper barrel portion 71 having a bore 72 extending therethrough and two elongated members 73 extending therefrom. The inner surface of clip holder 70 includes flat portions 74. The inner surface of clip holder 70 is adapted to receive clip 40 and includes grooves 75 that receive tangs 44 of clip 40.
Referring to FIGS. 13 through 20, clip pusher 80 includes barrel portion 81 having a bore 82 extending therethrough, and knurled end 83. Barrel portion 81 includes slots 84 formed in either side. As clip pusher 80 is slid along wrench 50, the lower end of each slot 84 engages a stop 56 to prevent further movement of clip pusher 80 along wrench 50. Ring 85 is disposed within knurled end 83 to frictionally engage upper shaft 57 of wrench 50 as clip pusher 80 is slid along wrench 50. The outer surface of clip pusher 80 includes flat portions 86 at its lower end corresponding to flat portions 74 of clip holder 70.
Compression screw 90, shown in FIG. 1, includes threaded shaft 91 which can be threaded into portion 25 of lag screw 20, and includes slot drive 92. Other well known drives, such as the hex drive, may be used.
In order to assemble compression screw assembly 10, clip pusher 80 is mounted, knurled end 83 first, over the lower shaft 52 of wrench 50 so that flat portions 53 of wrench 50 are aligned with slots 84 of clip pusher 80. Clip pusher 80 is slid along shaft 52 of wrench 50 until slots 84 engage stops 56 of wrench 50 and ring 85 engages upper shaft 57 of wrench 50. Clip 40 then is inserted within bore 72 of clip holder 70 so that flat portions 42 of clip 40 are aligned with flat portions 74 of clip holder 70 and tangs 44 of clip 40 are disposed within grooves 75 of clip holder 70. Elongated members 43 of clip 40 are disposed under elongated members 73 of clip holder 70. Clip holder 70, now containing clip 40, is mounted, barrel portion 71 first, over lower shaft 52 of wrench 50 until clip holder 70 engages clip pusher 80.
Once clip 40, clip pusher 80 and clip holder 70 are in place, compression plate 30 is slid end 36 first, over lower shaft 52 of wrench 50. Wrench stabilizing rod 60 is inserted within bore 51 of wrench 50. The threaded portion of stabilizing rod 60 is threaded within portion 25 of lag screw 20 and drive portion 24 of lag screw 20 is inserted within corresponding drive portion 54 of wrench 50.
To use the compression screw system of the present invention, the surgeon must first insert a guide wire in to the fractured bone, and then use a reamer to ream out the root diameter corresponding to the size of lag screw 20 and the opening for the outside diameter of the barrel member 31 of compression plate 30.
Because stabilizing rod 60 is cannulated, compression screw assembly 10 can be inserted over the guide wire. Lag screw 20 is then threaded partway into the bone by turning handle 58 of wrench 50. Compression plate 30 is slid forward over insertion wrench 50 and over shaft 22 of lag screw 20 until compression plate 20 is flush against the bone. Lag screw 20 is then threaded fully into the bone to the proper depth as indicated by depth markings 55 on wrench 50.
If lag screw 20 and compression plate 30 are to be inserted so that lag screw 20 is non-rotatably secured to compression plate 30, clip pusher 80 with clip holder 70 and clip 40 attached is pushed forward until clip holder 70 touches and centers on compression plate 30, then pushed again, more firmly, to slide clip 40 from within clip holder 70 and into barrel member 31 of compression plate 30 so that tangs 44 of clip 40 become disposed within indentations 35 of barrel member 31. Once clip 40 is in place, clip pusher 80 and clip holder 70 are slipped back down insertion wrench 50. Stabilizing rod 60 is unthreaded from lag screw 20 and wrench 50 and stabilizer rod 60 are removed.
Regardless of whether clip 40 is inserted, compression screw 90 may be inserted through barrel 31 of compression plate 30 and threaded into threaded portion 25 of lag screw 20 to obtain a tight compression between lag screw 20 and compression plate 30. Once the desired amount of compression has been achieved, compression screw 90 may be removed or left in place at the option of the surgeon.
Finally, compression plate 30 is anchored to the bone by inserting bone screws through apertures 38 of member 37 and into the bone. | A compression screw assembly for applying compression to a fractured bone includes a lag screw, a compression plate including a hollow barrel member adapted to receive the lag screw in at least one fixed orientation, a wrench assembly adapted to releasably engage the lag screw in axial alignment therewith, and apparatus having surface contours complimentary with the outer surface of the lag screw and inner surface of the barrel member for being optionally insertable into the barrel member to prevent axial rotation of the lag screw with respect to the barrel member 1. | 8 |
CROSS REFERENCE TO RELATED APPLICATIONS
The present application is a continuation application of U.S. Ser. No. 10/856,397 filed on May 28, 2004 now U.S. Pat. No. 7,145,134, which is a continuation application of U.S. Ser. No. 10/638,799 filed Aug. 11, 2003, now U.S. Pat. No. 6,909,090, which is a continuation of U.S. Ser. No. 10/025,508 filed Dec. 19, 2001, now U.S. Pat. No. 6,747,271.
FIELD OF THE INVENTION
The present invention is directed toward particle recording in multiple anode time-of-flight mass spectrometers using a counting acquisition technique.
BACKGROUND
Time-of-Flight Mass Spectrometry (“TOFMS”) is a commonly performed technique for qualitative and quantitative chemical and biological analysis. Time-of-flight mass spectrometers permit the acquisition of wide-range mass spectra at high speeds because all masses are recorded simultaneously. As shown in FIG. 1 , most time-of-flight mass spectrometers operate in a cyclic extraction mode and include primary beam optics 7 and time-of-flight section 3 . In each cycle, ion source 1 produces a stream of ions 4 , and a certain number of particles 5 (up to several thousand in each extraction cycle) travel through extraction entrance slit 26 and are extracted in extraction chamber 20 using pulse generator 61 and high voltage pulser 62 . The particles then traverse flight section 33 (containing ion accelerator 32 and ion reflector 34 ) towards a detector, which in FIG. 1 consists of micro-channel plate (“MCP”) 41 , anode 44 , preamplifier 58 , constant fraction discriminator (“CFD”) 59 , time-to-digital converter (“TDC”) 60 , and computer (“PC”) 70 . Each particle's time-of-flight is recorded so that information about its mass may be obtained. Thus, in each extraction cycle a complete time spectrum is recorded and added to a histogram. The repetition rate of this extraction cycle is commonly in the range of 10 Hz to 100 kHz.
If several particles of one species are extracted in one cycle, then these particles will arrive at the detector within a very short time period (possibly as short as 1 nanosecond). When using an analog detection scheme (such as a transient recorder in which the flux of charge generated by the incoming ions is recorded as a function of time), this near simultaneous arrival of particles does not cause a problem because analog schemes create a signal that is, on average, proportional to the number of particles arriving within a certain sampling interval. However, when a counting detection scheme is used (such as a time-to-digital converter in which individual particles are detected and their arrival times are recorded), the electronics may not be able to distinguish particles of the same species when those particles arrive too closely grouped in time. (A single signal is produced when a particle impinges upon the counting electronics. The signal produced by the detector is a superposition of the single signals that occur within a sampling interval.) Further, most time-to-digital converters have dead times (typically 20 nanoseconds) that effectively prevent the detection of more than one particle per species during one extraction cycle.
For example, when analyzing an air sample with twelve particles per cycle, there will be approximately ten nitrogen molecules (80% N 2 in air with mass of 28 amu) per cycle. In a time-of-flight mass spectrometer having good resolving power, these ten N 2 particles will hit the detector within two nanoseconds. Even a fast TDC with a half nanosecond bin width will not be able to detect all of these particles. Thus, the detection system will become saturated at this intense peak. FIG. 2 shows these ten particles 6 impinging upon a detector consisting of electron multiplier 41 (with MCP upper bias voltage ( 75 ) and MCP lower bias voltage ( 76 ) as indicated), single anode 44 , preamplifier 58 , CFD 59 , TDC 60 , and PC 70 . (MCP 41 in FIG. 2 consists of two chevron mounted multichannel plates. As would be apparent to one of skill in the art, circuitry would also be included to complete the electrical connection between the upper and lower plates. This additional circuitry is not shown in the figures.) TDC 60 will register only the first of these ten particles. The remaining nine particles will not be registered. Because only the first particle is registered, peaks for the abundant species (N 2 and O 2 ) will be artificially small and will be recorded too early, resulting in an artificially sharpened peak whose centroid is shifted to an earlier and incorrect time of flight. These two undesirable effects—incorrect intensity and artificially shortened time of flight—are referred to as anode/TDC saturation effects. These anode/TDC saturation effects are therefore different from the electron multiplier gain reduction (sometimes called multiplier saturation) that occurs when too many ions impinge the electron multiplier so that the electron multiplier is no longer able to generate an electron flux that is proportional to the flux of the incoming ions.
In an attempt to overcome anode/TDC saturation effects, some detectors use multiple anodes, each of which is recorded by an individual TDC channel. (An anode is the part of a particle detector that receives the electrons from the electron multiplier.) FIG. 3 shows such a detector with a single electron multiplier 41 and four anodes 45 of equal size. Each of the four anodes is connected to a separate preamplifier 58 and CFD 59 . Each of the four CFDs is connected to TDC 60 and PC 70 . This configuration permits the identification of intensities that are four times larger than those obtainable with a single anode detector. However, even with four anodes, the detection of the ten N 2 particles 6 leads to saturation since on average there will still be more than one particle arrival per anode. In principle, anode/TDC saturation could be avoided entirely by adding even more anodes. However, this solution is complex and expensive since each additional anode requires its own TDC channel.
Instead of using multiple anodes that each receive the same fraction of the incoming ions, one may use multiple anodes in which each anode receives a different fraction of the incoming ions. (The anode fraction is the fraction of the total number of ions that is detected by a specific anode.) By appropriately reducing this fraction, anode/TDC saturation effects can be reduced. See, for example, PCT Application WO 99/67801A2, which is incorporated herein by reference. One way to provide anodes that receive different fractions of the incoming ions is to provide electron multiplier 41 followed by anodes of different physical sizes as shown in FIG. 4 , in which large anode 46 is located adjacent to small anode 47 . As before, each anode is connected to a separate preamplifier 58 and CFD 59 , and the CFDs are connected to TDC 60 and PC 70 . In the example of FIG. 4 , two unequal sized anodes are provided having a size ratio of approximately 1:9. As a result, the small anode detects only one N 2 particle per cycle, which is just on the edge of saturation. Less abundant particles such as Ar (1% abundance in air and thus 0.12 particles per cycle) are detected without saturation on the large anode. Thus, with two anodes of unequal size it is possible to increase the dynamic range by a factor of approximately ten or more. A multi-anode detector with equal sized anodes would require ten anodes to obtain the same improvement.
In theory, the dynamic range of the unequal anode detector can be further reduced by further decreasing the size of the small anode fraction or by including additional anodes with even lower fractions. However, this theoretical increase in dynamic range is prevented by the presence of crosstalk from the larger anodes to the smaller anodes. In typical multi-anode detectors, the crosstalk from one anode to an adjacent anode ranges approximately from 1% to 10% when a single ion hits the detector. Thus, if 10 particles are detected simultaneously on a large fraction anode, the crosstalk to an adjacent small fraction anode may range from 10% to 100%. In such cases the small anode would almost always falsely indicate a single particle signal.
Bateman et al. (PCT Application WO 99/38190) disclose the dual stage detector shown in FIG. 5 where anode 47 , in the form of a grid or a wire, is placed between MCP electron multipliers 41 and 50 . However, instead of distributing different fractions of the incoming ion events (i.e., incoming particles 6 ) among different anodes, the detector of FIG. 5 distributes the secondary electrons of each ion event. They consider anode 47 to be the anode on which saturation effects are impeded. If anode 47 is a 10% grid, then anodes 47 and 46 each receive the same number of ion signals. The ion signals on anode 46 , however, are larger (on average) because of the additional amplification provided by MCP 50 . This type of additional amplification is useful in an analog acquisition scheme or in a combined analog/TDC acquisition system, in which the same principle has been used with dynode multipliers. However, in a pure TDC (or counting) acquisition system, increasing the dynamic range with two anodes of equal signal rates, but unequal signal sizes, is quite difficult.
Bateman et al. also suggest using different threshold levels on discriminators 59 to achieve different count rates on the two anodes. This suggestion, however, makes the detection characteristics largely dependent on the pulse height distribution of the MCPs. Also, the same technique could be applied with a single gain detector. Further, placing the small anode between the MCP and the large anode results in extensive crosstalk from the large anode to the small anode.
An object of the present invention is to provide a method and apparatus for reducing crosstalk and increasing dynamic range in multiple anode detectors. That is, an object of the present invention is to reduce crosstalk from anodes receiving a larger fraction of the incoming ions to those anodes that receive a smaller fraction of the incoming ions, thereby reducing the occurrence of false signals on the small fraction anode. A further object of the present invention is to provide a minimum variance procedure for combining—either in real time or off line—the counts from the separate anodes. A further object of the present invention is to provide a detector and associated electronics that will combine the signals from any mixture of small and large anodes to achieve a real time correction of ion peak intensity and centroid shift. A further objective of the present invention is to extend the dynamic range of a multi-anode detector by providing multiple electron multiplier stages where the electron multiplier gain reduction that occurs after the first stage is minimized in subsequent stages.
SUMMARY OF THE INVENTION
An ion detector in a time-of-flight mass spectrometer for detecting a first ion arrival signal and a second ion arrival signal is disclosed comprising a first electron multiplier with a first gain for producing a first group of electrons in response to the first ion arrival signal and for producing a second group of electrons in response to the second ion arrival signal. (Note that “first” and “second” are not temporal designations. In particular, the first ion arrival signal and the second ion arrival signal may occur simultaneously or in any temporal order.) Also disclosed is a first anode for receiving the first group of electrons but for not receiving the second group of electrons, thereby producing a first output signal in response to the first ion arrival signal. In addition, a second electron multiplier with a second gain greater than the first gain is disclosed for producing a third group of electrons in response to the second group of electrons but not in response to the first group of electrons. In addition, a second anode is disclosed for receiving the third group of electrons, thereby producing a second output signal in response to the second ion arrival signal. Finally, detection circuitry is disclosed that is connected to the first anode and the second anode for providing time-of-arrival information for the first ion arrival signal and the second ion arrival signal based on the first output signal and the second output signal.
An additional embodiment is disclosed in which the second electron multiplier is a micro-channel plate. In a further embodiment, the second electron multiplier is a channel electron multiplier. In yet another embodiment, the second electron multiplier is a photo multiplier. In an additional embodiment, the first electron multiplier comprises a micro-channel plate and an amplifier. In a further embodiment, a scintillator is positioned between the micro-channel plate and the amplifier.
In another embodiment, the detection circuitry comprises a first preamplifier receiving the first output signal from the first anode to produce a first amplified output signal, a second preamplifier receiving the second output signal from the second anode to produce a second amplified output signal, a first discriminator receiving the first amplified output signal to produce a first time-of-arrival signal, a second discriminator receiving the second amplified output signal to produce a second time-of-arrival signal, and a time to digital converter receiving the first time-of-arrival signal and the second time-of-arrival signal. In one embodiment, the first and second discriminators are constant fraction discriminators. In another embodiment, the first and second discriminators are level crossing discriminators.
In one embodiment a crosstalk shield is positioned between the first anode and the second anode. In another embodiment, an electrode is positioned to attenuate the ion arrival signals received by the second anode. In a further embodiment, detection circuitry is connected to the electrode for providing time-of-arrival information based on the ion arrival signals received by the electrode.
Also disclosed is a method for determining the times of arrival of a first ion arrival signal and a second ion arrival signal in a time-of-flight mass spectrometer, comprising the steps of providing a first electron multiplier with a first gain, producing from the first electron multiplier a first group of electrons in response to the first ion arrival signal, producing from the first electron multiplier a second group of electrons in response to the second ion arrival signal, providing a first anode, directing the first group of electrons so that the first group is received by the first anode, thereby producing a first output signal in response to the first ion arrival signal, directing the second group of electrons so that the second group is not received by the first anode, providing a second electron multiplier with a second gain greater than the first gain, producing from the second electron multiplier a third group of electrons in response to the second group of electrons but not in response to the first group of electrons, providing a second anode, directing the third group of electrons so that the third group is received by the second anode, thereby producing a second output signal in response to the second ion arrival signal, and calculating the times of arrival of the first ion arrival signal and the second ion arrival signal based on the first output signal and the second output signal.
Also disclosed is a method for combining TDC data collected from a plurality of anodes in an unequal anode detector comprising the steps of recording a histogram for each anode from the plurality of anodes, determining the effective number of TOF extractions seen by each anode from the plurality of anodes, determining the recorded number of counts on each anode from the plurality of anodes, estimating the number of impinging ions detected by each anode from the plurality of anodes, and correcting the recorded histogram for each anode from the plurality of anodes by substituting the estimate, and combining the corrected histograms into a weighted linear combination of minimal total variance. In an additional embodiment, the combining step comprises determining the fraction of incoming ions received by each anode from the plurality of anodes, and determining weights so that the weights sum to unity and so that the weighted combination has minimum variance.
Also disclosed is a method for estimating a global statistic by combining local statistics based on TDC data collected from a plurality of anodes in an unequal anode detector, comprising the steps of recording a histogram for each anode of the plurality of anodes, correcting each histogram for dead time effects by estimating the total number of particles impinging upon each anode of the plurality of anodes, thereby producing a plurality of corrected histograms, evaluating a local statistic for each corrected histogram, and combining the local statistics into a weighted linear combination to produce a global statistic with minimum total variance. In one embodiment, the local statistics are peak areas. In another embodiment, the local statistics are centroid positions. In a further embodiment, the local statistics are positions of peak maxima.
Also disclosed is a time-of-flight mass spectrometer, comprising an ion source producing a stream of ions, an extraction chamber receiving a portion of the stream of ions from the ion source, a flight section receiving the portion of ions from the extraction chamber and accelerating the portion of ions to produce a first accelerated stream of ions and a second accelerated stream of ions spatially separated from the first accelerated stream of ions, a detector receiving the first accelerated stream of ions and the second accelerated stream of ions from the flight section. The detector comprises a first electron multiplier with a first gain for producing a first group of electrons in response to the first accelerated stream of ions and for producing a second group of electrons in response to the second accelerated stream of ions, a first anode for receiving the first group of electrons and for not receiving the second group of electrons, thereby producing a first output signal in response to the first accelerated stream of ions, a second electron multiplier with a second gain greater than the first gain for producing a third group of electrons in response to the second group of electrons but not in response to the first group of electrons, a second anode for receiving the third group of electrons, thereby producing a second output signal in response to the second accelerated stream of ions, and detection circuitry connected to the first anode and the second anode for providing time-of-arrival information for the first accelerated stream of ions and the second accelerated stream of ions based on the first output signal and the second output signal. Also included is a data acquisition system for receiving the time-of-arrival information for the first accelerated stream of ions and the second accelerated stream of ions and for combining the time-of-arrival information into a weighted linear combination of minimum total variance.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram showing a prior art time-of-flight mass spectrometer to which the present invention may be advantageously applied.
FIG. 2 is a schematic diagram showing a single anode detector from the prior art.
FIG. 3 is a schematic diagram showing a multiple anode detector from the prior art.
FIG. 4 is a schematic diagram showing a detector from the prior art having multiple anodes of unequal size.
FIG. 5 is a schematic diagram of a prior art dual stage detector in which an anode in the form of a grid or a wire is placed between two MCP electron multipliers so as to distribute the secondary electrons of each ion event between itself and another anode.
FIG. 6 is a schematic diagram showing a detector of the present invention having a second stage MCP electron multiplier for ion events detected on the small fraction anode.
FIG. 7 is a schematic diagram showing an alternate embodiment of the detector of the present invention in which the second stage multiplier is a channel electron multiplier.
FIG. 8 is a schematic diagram showing an alternate embodiment of the detector of the present invention in which the second stage multiplier is omitted and the first stage multiplier contains a section with a higher electron multiplication (i.e., higher gain) for those ions to be detected on the small fraction anode.
FIG. 9 is a schematic diagram of a modification of the embodiment shown in FIG. 7 in which a separate first stage multiplier (as well as a separate second stage multiplier) is provided for the small fraction anode.
FIG. 10 is a schematic showing a detector of the present invention in which a scintillator is located between the two MCPs of the first stage multiplication to decouple the potential on the front MCP from the remainder of the detector, thereby better enabling the detector to detect ions in a high potential with a TDC acquisition scheme and electronics that are at or near ground potential.
FIG. 11 is a schematic showing an alternate embodiment for using a scintillator detector for high potential measurements.
FIG. 12 is a schematic diagram showing an alternate embodiment for using a scintillator detector for high potential measurements with CEMs or PMTs as second stage multipliers.
FIG. 13 is a schematic diagram of a detector in which the large anode is configured as a mask to restrict the ion fraction received by the small anode.
FIG. 14 is a schematic diagram showing a detector in which additional anodes (not connected to detection circuitry) are configured as a mask to restrict the ion fraction received by the small anode.
FIG. 15 is a schematic diagram showing a detector in which a mask in front of the first MCP restricts the ion fraction received by the small anode, and an additional multiplier stage 50 for the small anode is used to discriminate against crosstalk from the large anode.
FIG. 16A is a schematic diagram showing a symmetrical embodiment of the detector presented in FIG. 15 . FIGS. 16B and 16C are top views of Anodes 46 and 47 , respectively, in FIG. 16A .
FIG. 17 is a schematic diagram of an embodiment of the present invention in which the inner rim of the second MCP is used as a mask to reduce the ion fraction received by the small anode.
FIG. 18A is a schematic diagram of an embodiment of the present invention in which the secondary electrons are able to impinge anywhere upon the entire surface area of the collection anodes. FIGS. 18B and 18C are top views of Anodes 46 and 47 , respectively, in FIG. 18A .
FIG. 18D is a schematic diagram of another embodiment of the present invention in which the secondary electrons are able to impinge anywhere upon the entire surface area of the collection anodes. FIGS. 18E and 18F are top views of Anodes 146 and 147 , respectively, in FIG. 18D .
FIGS. 18G is a schematic diagram of an array constructed using sub-units as shown, for example, in FIGS. 18A and 18D . FIG. 18E shows the array of the large anodes from the direction of the incoming particles 6 , whereas FIG. 18F shows a top view of the array of small anodes.
FIGS. 19A and 19B show the application of the unequal anode principle to a position sensitive detector (PSD).
FIG. 20A shows a combination of a multi-anode detector and a meander anode. Here, large anode 46 ″ consists of a meander anode ( FIG. 20B ) and small anodes 47 ″ consist of a multi-anode array as shown in FIG. 20C . FIG. 20D shows a combination of multi-anode detector and meander anode in which the positions of the meander and multi-anode structures are interchanged from the orientation shown in FIG. 20A so that the large anode comprises the multi-anode 47 ′″ and small anode is meander 46 ′″.
FIG. 21A shows a hybrid detector consisting of a first multiplication stage using a MCP 41 and a second multiplication stage using another type of detector such as discrete dynode copper beryllium multiplier 94 . Discrete dynode multipliers are commercially available, and they may contain a multi-anode array of signal outlets as illustrated in FIG. 21B . It is possible to make an unequal anode detector from such a discrete dynode detector by combining certain of these outlets to produce large anode 46 ″″ and using a single outlet (or a reduced number of outlets) as small anode 47 ″″.
FIG. 22 is a flow chart showing a procedure to combine the information acquired by two or more unequal anodes into one combined spectrum.
FIG. 23 presents data showing a dynamic range comparison for three different anode fractions.
FIGS. 24 a - f present data comparing the centroid shifts for two different anode fractions.
DETAILED DESCRIPTION
In a typical time-of-flight mass spectrometer, as shown in FIG. 1 , gaseous partides are ionized and accelerated into a flight tube from extraction chamber 20 by the periodic application of voltage from high voltage pulsers 62 . A time-of-flight mass spectrometer may (as illustrated in FIG. 1 ) use reflectors to increase the apparent length of the flight tube and, hence, the resolution of the device. At detector 40 of the time-of-flight mass spectrometer in FIG. 1 , ions impinge upon electron multiplier (which is typically a dual microchannel plate multiplier) 41 causing an emission of electrons. Anodes detect the electrons from electron multiplier 41 , and the resulting signal is then processed through preamplifier 58 , CFD 59 , and TDC 60 . A histogram reflecting the composition of the sample is generated either in TDC 60 or in digital computer 70 connected to TDC 60 .
Referring to FIG. 6 , which illustrates a detector according to an embodiment of the present invention, incoming particles 6 impinge upon electron multiplier 41 to produce multiplied electrons 42 . Large anode 46 receives a large fraction of the incoming ions and hence becomes saturated for abundant ion species. Small anode 47 , however, receives only a small fraction of all incoming ions and hence does not saturate for abundant species. The detection fraction of anode 47 is small enough so that on average it detects only one particle out of the ten incoming particles of the species. (This particular detection fraction is chosen for illustrative purposes. Other detection fractions—including much smaller fractions—may be used without departing from the scope of the present invention.) Large anode 46 may be configured as shown to provide a mask for MCP 50 and small anode 47 . Also, as discussed below, crosstalk shield 48 may be positioned as shown to reduce the crosstalk from large anode 46 to small anode 47 . Anodes 46 and 47 are connected to separate preamplifiers 58 and CFDs 59 , which are connected to TDC 60 and PC 70 as shown.
As discussed above with regard to FIG. 4 , it is possible to increase the dynamic range by a factor of ten or more using two anodes of unequal size. A problem with this approach, however, is that crosstalk will generally occur from anode 46 to anode 47 . If this crosstalk is 10%, then ten simultaneous ions detected on anode 46 will generate crosstalk on anode 47 of the same intensity as one single ion detected on anode 47 . Thus, anode 47 may register an impact even if there was no ion present on anode 47 , thus leading to errors in the ion counting measurement.
The present invention provides a solution to this crosstalk problem. As shown in FIG. 6 , the signal on anode 47 is additionally amplified by second stage electron multiplier 50 . This second stage of amplification permits the threshold level on CFD 59 ′ to be increased to such a degree that cross talk from anode 46 will no longer be mistaken for a true ion signal. In particular, the present invention permits one to obtain a larger gain for ions detected on small anode 47 than for ions detected on larger anode 46 . This difference in gain may be achieved, for example, by including an additional MCP electron multiplication stage as shown in FIG. 6 . This embodiment also has another practical advantage over the approaches in FIG. 4 and FIG. 5 . Because the crosstalk from the large to the small anode is greatly reduced, the threshold levels of CFDs 59 and 59 ′ can be lowered consistent with the rejection of electronic signals from other noise sources. Therefore, MCPs 41 and 50 can be operated at a reduced bias voltage. The reduction in bias voltage results in a reduced secondary electron gain in electron multiplier 41 in response to particle flux 6 which in turn both prolongs the lifetime of the MCPs and allows them to respond to an increased particle flux 6 .
Other methods of electron multiplication may also be used in accordance with the present invention. For example, as shown in FIG. 7 , Channel Electron Multiplier (“CEM”) 91 may be used to provide the second stage multiplication that is provided by MCP 50 in FIG. 6 . One skilled in the art will immediately realize that other hybrid combinations of electron multipliers are possible as illustrated, for example, in FIG. 7B , which shows discrete dynode multiplier 94 for the small signal and a combination of one MCP 41 followed by a second electron multiplier comprising a Multi-Spherical Plate (MSP). Such choices of hybrids may be made to optimize detector response for both small and large anodes, increase detector lifetimes, and create detectors with higher count rate capabilities compared to the traditional dual MCP.
In the embodiments illustrated by FIG. 8 and FIG. 9 , a larger amplification is achieved by using MCPs of larger gain for those ions detected with anode 47 . In FIG. 8 , electron multiplier 41 consists of a single upper MCP 54 followed by a lower MCP 53 positioned in the path of large anodes 46 and a second lower MCP 52 positioned in the path of small anode 47 . In FIG. 9 , electron multiplier 41 consists of an upper MCP 55 and a lower MCP 53 positioned in the path of large anodes 46 and an upper MCP 56 and a lower MCP 52 positioned in the path of small anode 47 . Shielding electrode 48 serves to decrease the crosstalk from anodes 46 to anode 47 .
In certain mass spectrometers, MCP 41 (positioned at the front) operates on a very high potential so as to increase the ion energy upon impingement. In such a case, scintillators can be used to decouple the high potential side of the detector with the low potential side of the detector. FIG. 10 and FIG. 11 illustrate embodiments using this method and incorporating the second stage multiplication for anode 47 . Electron multiplier 41 in FIG. 10 consists of scintillators 81 positioned between MCP 54 and MCP 57 . Electron multiplier 41 in FIG. 11 consists of large scintillator 82 positioned between upper MCP 54 and lower MCP 53 , which is positioned in the path of large anodes 46 , and small scintillator 83 positioned between upper MCP 54 and lower MCP 52 , which is positioned in the path of small anode 47 . FIGS. 10 and 11 each show the MCPs in MCP pair 41 to be of the same size. However, it is not critical that he sizes be equal. Indeed, an advantage is obtained if the lower MCP ( 57 in FIG. 10 and 53 in FIG. 11 ) is increased in diameter with a subsequent increase in the diameter of scintillator 81 and 83 and in large anode 46 . In particular, if MCP 53 or 57 is larger than MCP 54 , then there will be more microchannels available than in MCP 54 and the gain reduction as a function of ion flux for the upper and lower MCP will be more closely comparable than if the MCPs were the same diameter. The function of the enlarged scintillator would then be to diffuse photons onto all available channels of lower MCP 57 or 53 . Lower MCP 57 or 53 is understood to contain a photocathode material to reconvert the scintillator photons into electrons for subsequent multiplication by the lower MCP.
FIG. 12 illustrates an embodiment that uses CEMs 92 and 93 in place of MCPs 52 and 53 , respectively. As before, CEM 92 , which is coupled to small anode 47 , preferably has a larger gain than CEM 93 . As would be clear to one of skill in the art, the CEMs in the detector of FIG. 12 may be replaced with Photo Multiplier Tubes (PMTs).
There are a number of ways for obtaining an unequal anode detector suitable for use with the present invention. For example, one may use anodes of different physical sizes. Alternatively, one may alter the electric and/or magnetic fields or the ion beam and detector geometry to change the fraction of incoming ions detected by a particular anode. One problem that may occur with these methods involves shared signals. In particular, some ions may produce electron clouds that strike more than one anode. These shared electron clouds typically produce smaller signals on each separate anode, and hence neither may be large enough to be counted, thus leading to an error in the ion counting. There are a number of procedures that may be used to minimize the effect of shared signals. First, the MCP and the large anode may be positioned close to each other so that the electron cloud produced by one ion will not be able to disperse between the MCPs or between the MCP and the anode. Second, anodes with large area-to-circumference ratios (e.g., round anodes) may be used to minimize the effect of shared signals. Third, the anodes may be offset and a small anode may be placed behind a large anode so that the large anode acts as a mask. For example, as illustrated in FIG. 14 , mask 49 may be used to restrict the ion fraction received by small anode 47 . In FIGS. 6-10 and FIG. 13 , large anode 46 is used as a mask in the same sense that mask 49 is used in FIG. 14 .
FIG. 15 illustrates an embodiment of the present invention in which mask 49 , which reduces the ion fraction of small anode 47 , is positioned in front of electron multiplier 41 . MCP 50 is the second stage multiplier for the small anode. The crosstalk from large anode 46 to small anode 47 is also minimized by shield 48 . This embodiment of the detector is capacitively decoupled by capacitors 77 . This decoupling allows the anodes to be floated to a high positive voltage while the electronics operate at or near ground potential.
FIG. 16A illustrates an embodiment that is similar to that depicted in FIG. 15 yet with a more symmetrical design. Top views of Anodes 46 and 47 in FIG. 16A are presented in FIGS. 16B and 16C , respectively. Again, the small anode count rate is reduced by mask 49 . Ions passing the mask towards the small anode are amplified with second stage multiplier 50 . The crosstalk from the large anode to the small anode is also minimized by shield 48 , which is shown with a capacitor between the shield and ground. This capacitor allows a high frequency ground path from shield 48 to ground. The anodes in this embodiment of the detector are not capacitively decoupled, but decoupling may be included if desired.
FIG. 17 illustrates an embodiment of the present invention in which a specially designed dual stack MCP 41 ′ is used in which the second MCP has a hole in it. Holes may be cut into the second channel plate by laser machining. When an excimer laser is used for machining a hole into an MCP, then an area around the rim of the hole concentric with the hole and about 50 microns wide will become dead for the purposes of electron multiplication. The inner rim dead area of the second MCP is thus used as a mask. The combination of this inherent dead area and the shape of large anode 46 serves both to eliminate shared signals and to reduce the ion fraction received by the small anode. In this case, the small anode is incorporated into CEM 91 . Any other electron multiplier may be used in place of CEM 91 so long as its multiplication factor is larger than the multiplication factor of the second MCP in first stage MCP stack 41 . For example, CEM 91 may be replaced by a dual channel plate assembly as shown in FIG. 17B . FIG. 17B also illustrates the use of defocusing element 48 to spread the electrons passing through anode 46 onto MCP 50 with multiplication onto anode 47 . Anode 47 and anode 46 have equal area in FIG. 17B .
FIG. 18A illustrates an embodiment in which the secondary electrons are able to impinge anywhere upon the entire surface area of Anodes 46 and 47 . Top views of Anodes 46 and 47 in FIG. 18A are presented in FIGS. 18B and 18C , respectively. The location of the second multiplier stage and the deliberate spreading of the electron cloud onto the second equal area anode 47 thus permit measurement of the same number of secondary electrons as the unequal area anodes in the previously described embodiments and in FIG. 4 and FIG. 5 . The spreading of the electrons onto the small fraction anode 47 anode is achieved by using electrodes 48 and 49 as defocusing electrostatic lenses. There are several advantages to this embodiment. The disadvantage of the crosstalk from the large to small anode combination of FIG. 4 has already been discussed, and the embodiment shown in FIG. 18A will solve this problem. In addition, however, there is yet another disadvantage to the approach in FIG. 4 that none of the embodiments described so far has overcome. This disadvantage comes from the non-proportional reduction in gain as a function of ion flux that occurs in the lower MCP of MCP pair 41 . This gain reduction is not related to electronics, but comes from the inability of MCP stage 41 to generate electrons after the initial particle flux becomes too high. It is well known that as one continues to increase the particle 6 flux, eventually the number of secondary electrons produced in response to each particle 6 by MCP 41 will begin to be reduced and that the lower of the two plates is where the gain reduction occurs first. In the end, as the particle flux is still further increased, the number of secondary electrons falls below the minimum necessary for detection by CFD 59 so that no count is registered even though many particles are striking MCPs 41 . It is also well known that this phenomena is caused by charge depletion in a micro-channel after a particle 6 has struck the channel and the channel has cascaded secondary electrons in response to this impact. Once this channel has “fired” in response to the particle impact, one must wait for anywhere from 100 microseconds up to a millisecond before it can again respond to an impact with an adequate production of secondary electrons. Furthermore, this charge depletion can actually affect nearest neighbor channels by drawing some of their charge as well, which thus also renders them less effective at producing secondary electrons in response to a subsequent particle impact. The third MCP 50 will allow efficient multiplication of the roughly 10 6 secondary electrons that were produced by the previous multiplier stage 41 . This will suppress crosstalk signals on the small anode 47 . The combination of MCP 50 , a defocusing lens element 48 , and a voltage bias applied to lens 48 results in a defocused electron cloud onto MCP 50 in a manner similar to that in FIG. 17B . A second independently biasable electrode 48 ′ is included to further spread the electron cloud onto MCP 50 . Electrode 49 may also function as a secondary gain stage if it is constructed of an appropriate material such as CuBe and biased in such a way to attract the electrons to collide with this element. It also functions as a shield to prevent scattered electrons from spilling over the edge of MCP 50 and anode 47 . The defocusing spreads the electron cloud over many more micro-channels on MCP 50 than would be the case if they were all concentrated into an area defined by the opening in anode 46 on MCP 50 . Therefore, the tendency of the third MCP 50 to suffer gain reduction as a function of the number of particles 6 impinging the detector is reduced. Such a defocusing stage can also be implemented between the two MCPs of the first multiplication stage 41 or the lower of the two MCP 41 plates can be replaced by some other type of higher gain electron multiplier. Alternatively, a defocusing lens between the MCPs in MCP pair 41 will allow for using a larger second MCP, which then will allow for higher ion flux.
The embodiment in FIG. 18D makes use of a hole in the second MCP plate with subsequent spreading of the electron cloud passing through this hole by biasing optical element 48 so that the electrons spread onto an equal area MCP 150 . This configuration provides the maximum dynamic count range possible from a collection of channel plates. It is well known that at high count rates the second channel plate in the stack begins to charge deplete before the top plate. In the first plate, between one and four channels are activated when an ion hits. The subsequent amplified electron cloud that exits the first plate will spread over multiple channels in the second plate even if the two plates are in close proximity or are touching. Therefore, many more channels will deplete in the second plate than in the first plate in response to an ion event. Transporting and spreading the electrons onto the second MCP stack 150 , which is acting as the multiplier for the small signal, results in a larger amplitude electrical signal on anode 147 in response to the restricted ion signal than will be generated by the dual stack MCP amplifier in front of anode 146 even for multiple simultaneous ion events. With this embodiment, the ion flux may become high enough to charge deplete the second channel plate of the stack in front of anode 146 so that anode 146 eventually no longer records any ion hits. Nevertheless, the first plate will produce enough electrons so that the small stack will still respond. The hole size of anode 146 and the second MCP plate may be selected so that the small anode signal will remain linear even though the signal generated by the first plates onto anode 146 are no longer large enough to exceed the threshold of the discriminator and thus be counted. FIGS. 18E shows anode 146 with a small hole rather than the slit of FIG. 18B Alternatively, an arrangement of rectangular slices of channel plate would eliminate the need to laser machine the second multi-channel plate if a configuration similar to FIG. 17B were desired. Note that the electrical signal from the small fraction anode 147 has the same or even a larger size than the large fraction anode 146 . The ion flux can be further increased by monitoring the count rate on each anode 146 and 147 for each detected mass peak, and determining which ones are of acceptable intensity and which are overly intense. At that point, after each extraction cycle, a voltage pulse of a few hundred volts can be applied through capacitive coupling to the MCP 141 stage to momentarily reduce its bias voltage (thus lowering its gain) for a few nanoseconds precisely at the times of arrival of the overly intense peaks at the MCP, thus reducing the gain during the arrival of intense peaks and ensuring that charge depletion in the MCP does not occur. This allows the entire detector response to subsequently remain linear for other less intense ions. The intensity of the intense peak can usually be inferred by use of peaks comprised of lower abundance isotopes. The same reduction could be obtained if the plates of MCP 141 were biased separately with a pulse being applied to either plate.
The embodiment in FIG. 18G is particularly useful for high count rate applications and is a combination, with modifications, of the embodiments shown in FIG. 17 and FIG. 18A . FIG. 18G shows an embodiment in which the concept of FIG. 18A is extended to an array structure. These are illustrated as four sub-units behind a rectangular MCP. It is clear that any number of these structures may be arranged either in linear fashion or in an array behind MCP 41 so that the position of impact of particles 6 on MCP 41 can be determined. Note that in FIG. 18G a different embodiment of cross talk shield 248 is illustrated. Shield 248 can be at a potential that is repulsive to the electrons coming from first stage multiplier 41 , hence forcing all electrons originating from one ion onto either of large anodes 246 , or through the opening in shield 248 towards second stage multiplier 250 . Electrode 249 may also function as a secondary gain stage if it is constructed of an appropriate material such as CuBe and biased in such a way to attract the electrons to collide with this element. It also functions as a shield to prevent scattered electrons from spilling over the edge of MCP 250 and anode 247 . This embodiment minimizes “signal sharing,” which is the dividing of the electron cloud originating from one single ion between different anodes. Anode 249 can be used to further disperse the electrons above anode 247 . FIGS. 18H and 18I show top views of anode arrays 246 and 247 , respectively.
FIG. 19 illustrates the application of the unequal area detector to Position Sensitive Detectors (PSDs). PSDs often have particularly long dead times and hence limited dynamic ranges. This makes the application of the unequal anode principle especially attractive. As in the case of the detectors discussed previously, large anode 46 ′ detects a large portion of incoming particles 6 . At least one additional anode 47 ′ detects a smaller fraction of incoming particles 6 and therefore has a decreased prospect for suffering from dead time effects. Again, an additional electron multiplication stage may be used to increase the signals of real ion events compared to signals from inductive crosstalk. In FIG. 19A , MCP 50 is used for this additional multiplication stage. Note again that “small” meander anode 47 ′ does not necessarily have to be smaller in size than large anode 46 ′, and in fact anode 48 may be biased to spread the electron cloud in an analogous manner to that shown in FIG. 18A . Small meander 47 ′ only has to detect a smaller fraction of the incoming particles 6 . Hence, it is possible to use two identical anode designs, where large anode 46 ′ masks the small anode, which means that it restricts the fraction of particle signals that are received by small anode 47 ′. Preferably, the two anodes are offset from each other so that small anode 47 ′ efficiently detects the particle signals that pass through the gaps of large anode 46 ′. Additionally, cross talk shield 48 may be used in order to minimize crosstalk and to defocus the electron cloud as desired. This is especially useful if second stage MCP 50 is omitted. FIG. 19B illustrates a top view of large meander anode 46 ′, which, as mentioned before, preferably has a similar shape as small anode 47 ′. The PSD detects the particle position along one dimension that is orthogonal to meander legs. It does so because the electron cloud divides and flows to both ends, and by evaluating the time difference of the signal on both ends of the meander anode one can measure where the electron cloud hit. As indicated in FIG. 19A , two distinct TDC channels on each meander are used to measure this time difference.
FIG. 20A further extends the concept to include a hybrid combination of discrete anodes 47 ″ ( FIG. 20C ) with meander 46 ″ ( FIG. 20B ) to monitor the small yield ions. This reduces by nearly one half the number of discrete channels of electronics necessary to run a multi-anode detector with an increased dynamic range. Instead of having discrete electronics for discrete anodes 47 ″, only two channels are required to encode the position by measuring the time difference of signals arriving at each end of the meander. Note that instead of the embodiment shown in FIG. 20A , the positions of anode 47 ″ (discrete anodes) could be interchanged with meander anode 46 ″. The resulting embodiment would be particularly useful in high count rate applications.
FIG. 21A illustrates the use of a discrete dynode detector such as a commercial copper beryllium detector as a TOF detector. Copper beryllium detectors have very high count rate capabilities and hence are useful for reducing saturation effects caused by charge depletion. Those detectors also typically have an array of signal outlets, which allows for some position detection. Combining several of those outlets into one TDC channel allows construction of large anode 46 ′″. A single outlet or a combination of a reduced number of outlets will produce small anode 47 ′″ ( FIG. 21B ). This allows exploiting the full dynamic range capability of such a detector even with a small number of TDC channels. Preferably, such a detector uses MCP 41 to convert the incoming ions 6 into electrons, which will minimize the time errors cause by flight path differences of ions impinging onto the entry surface of a copper beryllium detector 94 . If a TDC channel is connected to each of the 49 anodes, then the resulting configuration is similar to that in FIG. 3 . However, it is possible to use the configuration as a two channel device by electronically designating one of the 49 electrodes as the small anode and then electronically “ORing” the remaining 48 anodes within TDC 60 or PC 70 . Thus, two separate histograms may be maintained, each subdivided by an equal number of minimum time intervals. One histogram is incremented by one whenever the small anode is hit and the other is incremented by one when at least one of the other 48 anodes is hit. In this way, in high count rate applications, the amount of data that must be processed is reduced. This embodiment has the advantage that one configuration of the multi-anode detector hardware can be used for both high data rate applications when the application of small/large anode statistics are valid, while at the same time retaining the capability to capture each and every ion in applications where the total amount of ion signal is small. For example, when using gas samples with the mass spectrometer, time averaging abundant ion signals over many extractions using one equally sized anode for the “small” anode and any one of the other equally sized anodes for the “large” anode is statistically possible, whereas in a MALDI (Matrix Assisted Laser Desorption and Ionization) application the number of laser shots may be less than 100 and, because of limited sample size or ionization efficiency, the number of ions desorbed in each shot may be, for example, less than 10. In this MALDI case, the internal “ORing” would be removed and each anode would be used to count and assign an arrival time to each ion.
The embodiments shown in FIGS. 19 , 20 , and 21 can be particularly useful where both time and position information is desired. One use for these embodiments is to correct for timing errors caused by mechanical misalignments or electric field inhomogeneities in the time-of-flight mass spectrometer shown in FIG. 1 . The time-of-flight t of an ion of mass M from extraction chamber 20 to the face of detector 41 is given simply by t=k√{square root over (M)}. By using any of the embodiments shown in FIGS. 18G , 19 A, and 20 A, in combination with test ions of known molecular weight, it is possible to determine spectrometer constants for each separate anode 46 and 47 in FIG. 19 , for example. Once the spectrometer constant has been determined for each anode, then it is possible to store these values in PC 70 or in TDC 60 so that the arrival times of flight at each anode can be corrected to yield the true mass.
Another useful feature of the embodiments in FIGS. 19 , 20 , and 21 , when used with the orthogonal time of flight spectrometer in FIG. 1 , comes from the fact that the extent to which extraction chamber 20 is filled will depend on the mass of the ion. All ions are accelerated to the same energy so that light ions will travel far into extraction chamber 20 compared to heavier ions. Thus, ions hitting detector 40 are distributed non-uniformly across the detector as a function of ion mass. With arrays of anodes or position detectors this effect can be easily accommodated by anode positioning so that small anodes are always irradiated irrespective of mass. However, recognizing this mass dependence on the impact position onto anode 40 will require that if, for example, the detector in FIG. 18A is substituted for anode 40 in FIG. 1 , then the detector of FIG. 18A will need to be mounted so that the long axis of the anode in FIG. 18B is parallel with the direction of ion motion within extraction chamber 20 . Note that if the anode in FIG. 18B is orthogonal to the ion direction, then ions of too low a mass will not be sampled efficiently—or possibly not at all—by the anode in FIG. 18C .
In addition to the saturation effects described above, it is understood that the present invention may be used to overcome other dead time effects (such as a centroid shift, dynamic range restriction) known to those of skill in the art. In particular, with regard to both counts loss and centroid shifts, statistical methods may be used to further overcome saturation effects by reconstructing the original particle flux.
Combining the TDC Recordings of Different Anodes of an Unequal Anode Detector
This section describes a method for combining the TDC recordings received by different anodes in an unequal anode detector.
A. TDC Dead Time Correction for Isolated Bins or Isolated Mass Peaks.
An important property of TDC data recording is that, for each TOF start, it records for a given time bin only two events: (1) “zero,” which indicates the absence of particles, and (2) “one,” which indicates that one or more particles have impinged on the anode. An initial flow of particles may have a Poisson distribution denoted by
p k = λ k k ! ⅇ - λ ,
where p k denotes the probability that k particles are detected on the anode within a certain time span if the average number of detected particles in that time span is λ. The event “zero” corresponds to k=0, and hence occurs with probability p 0 =e −λ , whereas the event “one” has probability p 1 +p 2 +p 3 + . . . =1−p 0 =1−e −λ . For a known number of TOF extractions, N x , and recorded number of counts, N R , it follows that:
1
-
ⅇ
-
λ
≈
N
R
N
x
,
which
implies
that
:
λ
≈
-
ln
(
1
-
N
R
N
x
)
.
From the estimate for λ, the total number of particles impinging on the anode during N x extractions can be derived as:
N ~ R = λ · N x = - N x ln ( 1 - N R N x ) . ( 1 )
Equation (1) hence provides a method to correct for dead time effects in a TDC measurement. It reproduces the number of impinging particles Ñ R when N R events were recorded in N x extractions.
An estimate for the variance of Ñ R is given by:
σ 2 N ~ R ≈ σ 2 N R ( 1 - N R / N x ) 2 .
The value N R has a binomial distribution because it is the result of N x independent trials that have the possible outcomes “zero” and “one.” Thus, its variance is:
σ 2 N R =N x (1 −e −λ ) e −λ ≈N R (1 −N R /N x ). (2)
From this expression for the variance of N R , one obtains the following expression for the variance of the estimated quantity Ñ R :
σ
2
N
~
R
≈
N
R
(
1
-
N
R
/
N
x
)
.
(
3
)
These results are valid not only for isolated spectrum bins, but they are valid whenever the time span under consideration does not inherit any dead time from previous events. In practice, this means that all previous bins extending over a time range equal to the dead time must have very low count rates. If this is not the case, an additional correction explained in the next section may be applied.
As mentioned above, these results are also valid when applied to entire peaks that (1) have a width smaller than the dead time of the recording system, so that for each peak not more than one particle is recorded per extraction (i.e., trial), and (2) do not inherit dead time from previous peaks. These conditions are often fulfilled in TOF mass spectrometry since typical dead times of current TDCs are in the range of τ=20 ns, whereas for gaseous analysis, for example, typical peak widths are in the range of 2 ns and the distance between peaks is often more than 100 ns.
B. TDC Dead Time Correction for Non-Isolated Bins or Non-Isolated Peaks.
Suppose that the dead time of the data recording system τ is known and that this system is working in a “blocking mode” in which a particle falling into a dead time does not re-trigger the dead time but instead is fully ignored. Then, the k th bin may include dead time effects from particles recorded in preceding bins. Assuming a bin width τ b , there are about m=τ/τ b previous bins that may contain such events. Whenever such an event occurred, there was no way that the k th bin could have recorded a particle. This in effect is equivalent to stating that the k th bin has experienced a decreased number of extractions (i.e., trials). This decreased effective number of extractions can be expressed as:
N
x
′
(
k
)
≈
N
x
-
∑
j
=
1
round
(
m
)
N
R
(
k
-
j
)
.
A more precise result that considers the fact that m is not an integer, is:
N x ′ ( k ) = N x - ∑ j = 1 j ≤ τ / τ b - 1 N R ( k - j ) - ( δ + 0.5 - 0.5 δ 2 ) N R ( k - j 0 ) - 0.5 δ 2 N R ( k - j 0 - 1 ) , ( 4 )
where j 0 =[τ/τ b ] is the integer portion of the number in the square brackets and δ=τ/τ b −j 0 . This value for the effective number of extractions may then be substituted into Equation (1) to obtain:
N ~ R = λ · N x = - N x ln ( 1 - N R N x ′ ) . ( 5 )
Additional information regarding these estimates may be found in T. Stephan, J. Zehnpfenning, and A. Benninghoven, “Correction of dead time effects in time-of-flight mass spectrometry,” J. Vac. Sci. Technol. A 12(2), March/April 1994, pp. 405-410, which is incorporated herein by reference. The corresponding (conditional) variance is:
σ
2
N
~
R
=
N
R
N
x
2
(
1
-
N
R
/
N
x
′
)
(
N
x
′
)
2
.
(
6
)
Equation (6) provides an estimate of the variance for the reconstructed number of ions when the value N x ′ is known precisely. In practice, N x ′ will not be known precisely primarily because the dead time τ is not known precisely. A more precise estimate of the variance of Ñ R may be obtained by considering the variance of N x ′ and covariance of N R and N x ′:
σ
2
N
~
R
=
N
R
N
x
2
(
1
-
N
R
/
N
x
′
)
(
N
x
′
)
2
+
N
R
2
N
x
2
σ
2
N
x
′
(
1
-
N
R
/
N
x
′
)
2
(
N
x
′
)
4
+
2
N
R
N
x
2
cov
(
N
x
′
,
N
R
)
(
1
-
N
R
/
N
x
′
)
2
(
N
x
′
)
3
.
(
7
)
The value of σ 2 N x ′ depends primarily on the uncertainty Δτ of the dead time τ, which is determined by the acquisition electronics in most cases. It has been found that such uncertainties, caused by electronics in the data acquisition system, is rather large. Depending on the specific electronic components in use, it is possible to find an estimate for σ 2 N x ′. For example, one can estimate σ 2 N x ′ by increasing and decreasing the dead time τ in Eq. (4) by Δτ and monitoring how N x ′ changes. The square of the total change is then an estimate for σ 2 N x ′. The third term, which includes cov(N x ′, N R ), becomes zero if there is no correlation between N x ′ and N R .
C. Method to Combine the Recordings of the Anodes of an Unequal Anode Detector.
The results of the previous section are also valid when the data is recorded using several anodes, each receiving different fractions of the incoming particles, since all anodes independently experience a Poisson particle inflow. The following discussion considers the case of two unequal anodes, where the so-called “big anode” receives a larger fraction of the incoming particles: Ñ RB =a·Ñ RS . The coefficient a may be experimentally determined (for example, by recording at low particle fluxes where dead time effects are not present), and hence:
a
=
N
~
RB
N
~
RS
≈
N
RB
N
RS
.
(
8
)
Also, in the case where the anode fraction turns out to be different for different mass peaks, α can be determined for every individual peak. Similarly, a may depend on the total ion flux and hence may have to be recalibrated periodically.
After the anode fraction a has been determined, an estimate of the ion count rate can be derived. With increasing ion flux, the large anode experiences an increasing saturation effect, which results in a decreasing accuracy of the count rate determined on the large anode as shown by Equation (2). This accuracy may be improved, however, by taking into account the less saturated measurement of the small anode. In order to optimize the accuracy, it is necessary to find the linear combination,
Ñ=αÑ RB +βaÑ RS , (9)
of the two anodes that has minimal variance under the constraint α+β=1. This constrained minimization yields:
α = a 2 σ 2 N ~ RS a 2 σ 2 N ~ RS + σ 2 N ~ RB and β = σ 2 N ~ RB a 2 σ 2 N ~ RS + σ 2 N ~ RB , ( 10 )
where the required variances are given by Equation (3), (6), or (7) in order to substitute N RS and N RB , which are the recorded counts for small and big anode, respectively. The variance of this optimal linear combination Ñ is:
σ
2
N
~
=
a
2
σ
2
N
~
RS
σ
2
N
~
RB
a
2
σ
2
N
~
RS
+
σ
2
N
~
RB
.
(
11
)
Hence, Equation (6) indicates how to optimally combine the recordings of the two anodes after the recorded count rates have been statistically corrected by Equation (1) or (3). The anodes of an unequal anode detector with more than two anodes can be combined accordingly.
Thus, the recorded histograms of an unequal anode detector may be combined using the following procedure, which is illustrated in FIG. 22 :
Step 1: Evaluate anode ratio a if it is unknown. Step 2: Independently record the histogram of both anodes and correct those histograms according to Equation (1) or (5), whichever applies. Step 3: Combine the two histograms by applying Equation (9) for each bin or each peak, using the proper weights α and β derived with Equation (10).
A slightly modified procedure is preferred if the peak shapes on the different anodes are not sufficiently equal:
Step 1: Evaluate anode ratio a if it is unknown. Step 2: Independently record the histogram of both anodes and correct those histograms according to Equation (1) or (5), whichever applies. Step 3: Evaluate the desired properties (e.g., peak area, centroid position) and their variances from each corrected spectrum. Step 4: Combine the desired properties by applying Equation (9) for each peak, using the proper weights α and β derived by minimizing the variance, e.g., with Equation (10).
Note that for this second procedure, the ratio a may be adjusted for each property, e.g., each mass peak may have its own ratio a.
The statistical correction outlined above has been discussed in the context of evaluating the number of counts in peaks or bins only. A similar method may be used for the evaluation of the peak position or other properties to be evaluated from the spectrum. For example, an exact mass determination of an ion species requires the exact determination of its peak position in either the TOF histogram or the mass histogram. Either the peak centroid t , m or the peak maximum t max ,m max are often used to represent the position of a peak. Both properties are subject to shifts in the case of saturation. Hence, for saturated regions of the large anode histogram, it may be better to rely more heavily on the small anode histogram for the evaluation of the peak position. Therefore, by replacing the count rate N by either t , m or t max ,m max the method presented above may be used to obtain an estimate of the peak position. Note that for the evaluation of the peak position, a=1, since the large and the small anodes reveal the same position, e.g., a small anode reduces the number of counts but not the position of a peak.
The equations above can easily be adapted for any number of unequal anode arrays in an unequal anode detector. FIG. 23 shows an application of this statistical treatment to data taken from a gas sampling mass spectrometer into which atmospheric air is introduced. All of the data was taken at a TOF extraction frequency of 50 kHz. Thus, the x-axis, displaying ion count rates from 1000 N 2 ions per second to 2 million N 2 ions per second, cover the range from 0.02 to 40 ions per extraction. The y-axis displays the measured N 2 /O 2 ratio (in air), which should be constant. FIG. 23 shows that for a conventional single anode configuration, saturation occurs at 10,000 ions per second (0.2 ions per extraction, i.e., 0.2 ions hitting the anode simultaneously). For a state of the art two-anode detector, saturation of the small anode begins at approximately 100,000 counts per second on the large anode (two ions hitting the detector simultaneously), if no additional saturation correction is applied. With the present invention, saturation can be avoided up to at least 2 million ions per second (40 ions hitting the detector simultaneously).
FIGS. 24 a - f compare peak centroid measurements done on a large ion fraction anode ( FIGS. 24 a - c ) with such measurements on a small ion fraction anode ( FIGS. 24 d - f ). The ion fraction on the small fraction anode is 10 times lower than on the large fraction anode. The ion incident rate is very low on the measurement shown in FIGS. 24 a and 24 d (approx. 0.11 ions per extraction) to avoid any saturation effect, especially any peak shift caused by dead time effects. The ion rate is then increased to 1.1 ions per extraction ( FIGS. 24 b and 24 e ) and it is then even further increased to 4.4 ions per extraction ( FIGS. 24 c and 24 f ). It is evident that the peak measured on the anode receiving a large ion fraction ( FIGS. 24 a - c ) is shifted to the left in the course of this ion rate increase. The peak measured on the small fraction anode ( FIGS. 24 d - f ), however, experiences a much smaller shift. This is evidently because its saturation is 10 times less severe as it receives a ten times decreased ion rate. This measurement indicates how it is possible to increase the accuracy of a mass measurement of intense peaks using an unequal anode system, when using a dead time affected TDC data acquisition system.
CONCLUSION
The present invention, therefore, is well adapted to carry out the objects and obtain the ends and advantages mentioned above, as well as others inherent herein. All presently preferred embodiments of the invention have been given for the purposes of disclosure. Where in the foregoing description reference has been made to elements having known equivalents, then such equivalents are included as if they were individually set forth. Although the invention has been described by way of example and with reference to particular embodiments, it is not intended that this invention be limited to those particular examples and embodiments.
It is to be understood that numerous modifications and/or improvements in detail of construction may be made that will readily suggest themselves to those skilled in the art and that are encompassed within the spirit of the invention and the scope of the appended claims. For example, as is clear to those of skill in the art, the anodes used in accordance with the present invention are not required to each be associated with a single electron multiplier. In particular, a detector according to the present invention may include more than one electron multiplier with each anode detecting an unequal fraction of the incoming particle beam from one or more of those electron multipliers.
Although the techniques here have been described with respect to ion detection in time of flight mass spectrometry, those of skill in the art will recognize that the hardware and methods are equally applicable to the detection of electrons or photons. In the case of photons, a photocathode is placed in front of or incorporated onto the detector surface. These techniques are equally applicable to the cases in which a specially shaped converter surface, which might for example be flat, is used to convert energetic particles of any type into electrons that are then transported by electrostatic, magnetic, or combined electrostatic and magnetic fields onto the detector embodiments that have been described herein.
The invention may also be used with focal plane detectors in which the mass (or energy) of a particle is related to its position of impact upon the detector surface. In this case, the number of ions per unit length is summed into a spectrum. The anode saturation effects that occur in such a detector result from more than one ion impinging upon an anode during the counting cycle of the electronics.
Finally, it will be immediately apparent to those of skill in the art that the invention may also be used effectively in applications requiring analog detection of ion streams. In this case, the TDC channels behind each anode are replaced by input channels in a multiple input oscilloscope or by multiple discrete fast transient digitizers. The biases on the appropriate electron multiplier are adjusted so that the analog current response of the multiplier is a linear function of the incoming ion flux. | A detection scheme for time-of-flight mass spectrometers is described that extends the dynamic range of spectrometers that use counting techniques while avoiding the problems of crosstalk. It is well known that a multiple anode detector capable of detecting different fractions of the incoming particles may be used to increase the dynamic range of a TOFMS system. However, crosstalk between the anodes limits the amount by which the dynamic range may be increased. The present invention overcomes limitations imposed by crosstalk by using either a secondary amplification stage or by using different primary amplification stages. | 7 |
INCORPORATION BY REFERENCE
[0001] The present application claims priority under 35 U.S.C. §119 to Japanese Application No. 2005-322115, filed on Nov. 7, 2005. The content of the application is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a insert with a replaceable cutting edge. More specifically, the present invention relates to a replaceable-blade cutting insert and corner milling cutter with replaceable cutting edge using the same, in which the squareness of the cut corner and the flatness of the vertical wall of the cut corner are improved. The corner milling cutter of the present invention also includes end mills with replaceable cutting edges.
[0004] 2. Description of the Background Art
[0005] Among widely known corner milling cutters, there are ones in which a cutting section is formed as an insert with a replaceable cutting edge (Japanese Laid-Open Patent Publication Number 2003-266232, Japanese Laid-Open Patent Publication Number 2004-291205, and the like). In the corner milling cutter with replaceable cutting edge described in Japanese Laid-Open Patent Publication Number 2003-266232, a parallelogram negative insert is mounted on a base positioned at an outer perimeter of an end of a main cutter body, with the side surface forming the rake face and the end surface (either the upper or lower surface) forming the outer perimeter flank face. In this type of cutter, the use of a parallelogram or trapezoid insert makes it possible to provide a positive axial rake. Since the flank face is formed at the outer perimeter flank face, the radial rake has to be a negative angle.
[0006] A negative radial rake, however, reduces the cutting quality of the cutter. To overcome this, Japanese Laid-Open Patent Publication Number 2004-284010 describes a cutter insert in which the base unit is twisted around two axial lines. In the cutter insert in Japanese Laid-Open Patent Publication Number 2004-284010, a height offset is formed at the ceiling surface or the base surface forming the rake face toward the corner side, thus providing a positive radial rake angle by providing a flank angle on the outer perimeter flank face. A similar cutter insert is also disclosed in WO2005/075135.
[0007] Referring to FIGS. 11A-11D , the problems involved with corner milling cutters that use rhombus chips will be described. In the cutter in FIG. 11 , a rhombus insert 20 D is mounted at the outer perimeter at the end of a main cutter body 31 so that the axial rake γp is positive, the radial rake γf is negative, the face angle (front cutting section angle) κ′ is positive, and the approach angle Ψ is positive. When the insert 20 D is sloped so that an end point P 2 of a ridge line 7 forming the main cutting section passes through the same circle as a path circle S of an end point P 1 , the sections of the ridge line 7 excluding its ends pass positions outside of the path circle S. As shown in FIG. 11D , the amount by which the ridge line 7 departs from the path circle S is greater toward the center of the ridge line. As shown in FIG. 12 , a wall surface wf of a workpiece A cut by the ridge line 7 will form a surface that is expanded toward the middle, thus reducing the squareness of the cut corner.
[0008] Japanese Laid-Open Patent Publication Number 2004-291205 describes a technology that allows an insert to be tilted in a direction where the approach angle Ψ is a positive angle. As shown in FIG. 11 , by having a positive angle for the approach angle Ψ, the end point P 2 of the ridge line 7 can be positioned on the path circle S and the path of the main cutting section can be made to approach a direction that would be parallel with the axial line of the cutter.
[0009] This method, however, cannot overcome the problems described above.
[0010] Also, Japanese Laid-Open Patent Publication Number 2004-284010 and WO2005/075135 do not appear to make a special effort to improve the flatness of the wall surface of the workpiece or the squareness of the cut corner. The same applies to Japanese Laid-Open Patent Publication Number 2003-266232. As described in Japanese Laid-Open Patent Publication Number 2004-284010 and WO2005/075135, in a cutter with a height offset at the rake face so that the surface position is higher toward the corner and a radial rake that can be set up as a positive angle, inferior flatness of the wall surface of the workpiece and squareness of the cut corner becomes more prominent.
SUMMARY OF THE INVENTION
[0011] The object of the present invention is to improve the shape of an insert with replaceable cutting edge in order to improve the squareness of the corner and the flatness of the cut wall surface of a workpiece cut with a corner milling cutter that uses this insert.
[0012] In order to achieve this object, the present invention provides a replaceable-blade cutting insert for corner milling cutters including: a first surface and a second surface facing opposite directions; a third surface and a fourth surface intersecting with and connecting to the first surface and the second surface; a fifth surface and a sixth surface intersecting with the first surface and the second surface and the third surface and the fourth surface; wherein the first surface is used as a rake face, the third surface is used as an outer perimeter flank face, and the fifth surface is used as a front flank face. In addition, a twisted surface is formed at a section of the third surface, intersecting with the first surface and creating with the first surface a ridge line serving as a main cutting section. The twisted surface is sloped in a direction that increases an intersection angle with the first surface and is formed with a width W that gradually decreases as a distance from an end of the ridge line increases
[0013] Preferable aspects of this replaceable-blade cutting insert are as follows. (1) A height offset is formed on the first surface so that a surface position toward a corner is higher. This height offset can be set so that all four corners are raised or only a first pair of diagonal corners can be raised. (2) A positive land is formed on an outer perimeter section of the first surface. (3) A section of the third surface excluding the twisted surface includes two flat surfaces, the two flat surfaces intersecting at an obtuse angle to form a hump when the first surface is viewed from a front view. (4) An angle of a corner where the fifth surface and the third surface intersect is no more than 95 deg. (5) When the insert is rotated 180 deg along a horizontal plane, an outline shape stays identical between the third surface and the fourth surface and between the fifth surface and the sixth surface. (6) When the insert is flipped around a bisecting line (L) bisecting a height axis of the first surface, an outline shape stays identical between the first surface and the second surface.
[0014] A replaceable-blade corner milling cutter is completed when one of these replaceable-blade cutting insert is mounted on a base disposed at an outer perimeter of an end of a main cutter body so that the first surface serves as a rake face, the third surface including the twisted surface serves as an outer perimeter flank face, the fifth surface serves as a front flank face, the ridge line between the first surface and the twisted surface serves as a primary cutting section, and a ridge line between the first surface and the fifth surface serves as a secondary cutting section, and so that a axial rake (γp) is positive or negative, a radial rake (γf) is negative, and an approach angle (Ψ) is 0 deg. The present invention also provides this replaceable-blade corner milling cutter.
[0015] When the twisted surface described above is formed from a section of the third surface serving as the outer perimeter flank face, the ridge line formed between the first surface serving as the rake face and the twisted surface (the ridge line serving as the main cutting section) is shaped so that it is expanded outward around an intermediate longitudinal position when the first surface is seen directly from the front. Also, the dulling effect of the twisted surface on the cutting edge increases the strength of the cutting edge.
[0016] When a height offset is provided for the first surface to raise the surface toward the corner, an outer perimeter flank is formed on the third surface and positive angle radial rake γf is applied to the cutting edge, thus improving the cutting quality of the cutting edge. When a height offset is formed on the first surface so that only one set of diagonal corners are raised, the axial rake γp is also set to be positive, providing further improvements in cutting quality. When all four corners of the first surface are raised, it may not be possible to set the axial rake γp to be positive. But even if the axial rake γp has to be negative, the rake angle is larger compared to a structure with no height offset in the first surface, so the cutting quality is improved. When a positive land is formed on the outer perimeter section of the first surface, the cutting edge can be made sharp and the cutting quality can be improved.
[0017] Also, when a section of the third surface excluding the twisted surface forms a hump when the first surface is viewed directly from the front, a positive face angle can be applied with an approach angle at 0 deg.
[0018] Furthermore, when the corner at which the fifth surface and the third surface intersect has an angle of no more than 95 deg, it is easy to provide a positive face angle (front cutting section angle).
[0019] In addition, with a structure where, when the insert is rotated 180 deg along a horizontal plane, an outline shape stays identical between the third surface and the fourth surface and between the fifth surface and the sixth surface, two diagonal corners or four corners of the first surface can be used as cutting sections. In addition, with a structure where, when the insert is flipped around a bisecting line (L) bisecting a height axis of the first surface, an outline shape stays identical between the first surface and the second surface, two diagonal corners or four corners can be used as cutting sections, thus increasing economic advantages.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIGS. 1A-1F are examples of a replaceable-blade cutting insert according to the present invention. 1 A: front-view drawing. 1 B: side-view drawing. 1 C: bottom-view drawing. 1 D: a cross-section drawing along the I-I line in FIG. 1A . 1 E: A cross-section drawing along the II-II line in FIGS. 1A . 1 F: A drawing showing the fifth (sixth) surface formed with a hump.
[0021] FIG. 2 is a simplified drawing showing the main elements of the insert from FIG. 1 being used.
[0022] FIGS. 3A-3D are another examples of a replaceable-blade cutting insert according to the present invention. 3 A: front-view drawing. 3 B: side-view drawing. 3 C: a cross-section drawing along the III-III line in FIG. 3A . 3 D: A drawing showing the fifth (sixth) surface formed with a hump.
[0023] FIGS. 4A-4C are further examples of a replaceable-blade cutting insert according to the present invention. 4 A: front-view drawing. 4 B: side-view drawing. 4 C: simplified drawing showing the main elements of the structure in use.
[0024] FIGS. 5A-5C are examples of a replaceable-blade cutting insert according to the present invention. 5 A: front-view drawing. 5 B: side-view drawing. 5 C: simplified drawing showing the main elements of the structure in use.
[0025] FIG. 6 is a perspective drawing showing an example of a corner milling cutter according to the present invention.
[0026] FIG. 7 is a side-view drawing of the cutter from FIG. 6 .
[0027] FIG. 8 is a front-view drawing of the cutter from FIG. 6 .
[0028] FIG. 9 is a detail perspective drawing of an insert mounting section of the cutter from FIG. 6 .
[0029] FIG. 10 is a perspective drawing of another example of a corner milling cutter according to the present invention.
[0030] FIGS. 11A-11D are simplified drawings of a prior art corner milling cutter using a rhombus chip; 11 A: front-view drawing. 11 B: cross-section drawing. 11 C: side-view drawing. 11 D: detail drawing of the circled frame in the front-view drawing A.
[0031] FIG. 12 is a cross-section drawing exaggerating the corner surfaces cut with the cutter from FIG. 11 .
DETAILED DESCRIPTION OF THE INVENTION
[0032] FIG. 1 through FIG. 5 show a specific example of an insert with replaceable cutting edge according to the present invention. In FIG. 1 , a replaceable cutting edge insert 20 is formed as an insert with: a long first surface 1 and a second surface 2 facing in opposite directions; a third surface 3 and a fourth surface 4 intersecting with and connected to a first side edge and a second side edge of the first surface 1 and the second surface 2 ; and a fifth surface 5 and a sixth surface 6 intersecting with and connected to a first end and a second end of the first surface 1 and the second surface 2 . The fifth surface 5 and the sixth surface 6 are also connected, by way of corner curve surfaces 9 to a first end and a second end of the third surface 3 and the fourth surface 4
[0033] The first surface 1 and the second surface 2 are surfaces formed with the same shape, and these surfaces can be switched to serve as rake faces. Positive lands 11 are formed at the outer perimeters of the first surface 1 and the second surface 2 so that the rake angle of the cutting edge is positive, and the central sections 1 a, 2 a are formed as lowered surfaces. The surface positions gradually increase going from corners C 2 , C 4 to a corner C 1 and likewise going from corners C 2 , C 4 to a corner C 3 . Of the four corners C 1 -C 4 , one set of diagonal corners C 1 , C 3 are formed so that they are positioned at the outermost ends when seen in the figure (see FIG. 1B ) that looks directly at the third surface 3 (or the fourth surface 4 ). The positive land 11 is preferable but not required.
[0034] A ridge line 7 is provided at the curve formed where a twisted surface 10 and the first surface 1 intersect and where the twisted surface 10 and the second surface 2 intersect, and this ridge line 7 is used as a main cutting section. A ridge line 8 is a ridge line formed between the first surface 1 and the fifth and sixth surfaces 5 , 6 and between the second surface 2 and the fifth and sixth surfaces 5 , 6 . This is used as a secondary cutting section.
[0035] The third surface 3 and the fourth surface 4 are also formed as surfaces with identical shapes, and these are used as outer perimeter flank faces. The fifth surface 5 and the sixth surface 6 are also formed as surfaces with identical shapes, and these are used as front flank faces.
[0036] Sections of the third surface 3 and the fourth surface 4 , i.e., the sections along the surfaces 1 , 2 , form the twisted surfaces 10 . The twisted surfaces 10 are formed as four surfaces at the third surface 3 and the fourth surface 4 . The twisted surfaces 10 are sloped so that the angle of intersection with the positive lands 11 formed on the first and second surfaces 1 , 2 increase. Also, the twisted surfaces 10 are formed so that a width W (see FIG. 1B ) gradually decreases as the distance from the corners of the third and fourth surfaces 3 , 4 increases. It can be preferable for the slope angle a (see FIG. 1E ) of the twisted surface 10 relative to the third surface 3 and the fourth surface 4 to be set to approximately 3-15 deg. If a is 3 deg or less, the increased cutting edge strength provided is small. Also, if α is 15 deg or more, flatness for the wall surface of the workpiece becomes difficult to obtain.
[0037] As shown in FIG. 1A , where the first surface 1 is seen directly from the front, the presence of the twisted surfaces 10 results in the ridge line 7 expanding outward around an intermediate longitudinal position. As shown in FIG. 2 , with the insert 20 sloped so that the axial rake is positive and the radial rake is negative, the rotation path of the main cutting section formed by the ridge line 7 can form a straight vertical line with an approach angle Ψ that is roughly 0 deg. This improves the squareness of the cut corner surface and improves the flatness of the cut wall surface.
[0038] Also, compared to not forming the twisted surface 10 , the use of the twisted surface 10 results in a more obtuse intersection angle with the positive land 11 (see FIG. 1E ). This improves the strength of the main cutting edge.
[0039] In this replaceable cutting edge insert 20 shown in FIG. 1 , out of the four corners C 1 -C 4 of the first surface 1 (or the second surface 2 ), the pair of diagonal corners C 1 , C 3 are used as cutting edges. By forming a large height offset on the first surface 1 and increasing the height of the diagonal corners C 1 and C 3 , when the insert is upright as shown in FIG. 1B , the diagonal corners C 1 , C 3 project significantly in the direction away from a lateral center line C of the third surface (in the direction in which the rake angle increases), and the slope of the ridge line 7 relative to the center line C increases (the same applies to the second surface 2 side). As a result, the axial rake of the cutting section is increased and the quality of cuts is improved. When the insert is upright as shown in FIG. 1B , the axial rake can be increased, e.g., up to approximately +5 deg, making it possible to provide a “high-rake” corner milling cutter.
[0040] It can be preferable for the fifth surface 5 and the sixth surface 6 to intersect with the third surface 3 and the fourth surface 4 at an angle of no more than 95 deg. As shown in FIG. 1F , when the fifth surface 5 and the sixth surface 6 protrude on both sides by an angle β of a few degrees (or the angle can be 1 deg or less), to form a sloped hump surface, a positive face angle κ′ can be applied to an insert with an approach angle Ψ of 0 deg ( FIG. 2 ).
[0041] The sections of the third surface 3 and the fourth surface 4 outside of the twisted surfaces 10 can be formed from multiple flat and curved surfaces. It is also possible to have the ridge line 7 serving as the main cutting section formed as a straight ridge line, and the ridge line 8 serving as the secondary cutting section formed as a curved ridge line. Furthermore, in the replaceable cutting edge insert 20 shown in FIG. 1 , the diagonal corners C 1 , C 3 of the surfaces 1 , 2 are formed higher than other sections, and the corners C 1 , C 3 are used as cutting edges, with the corners C 1 , C 3 and the corners C 2 , C 4 being formed with different shapes. However, it is also possible to have an insert where all four corners are formed with the same shape.
[0042] FIG. 3 shows an insert according to another example. This replaceable cutting edge insert 20 A is an insert that is based on rectangular parallelepiped shape. The four corners C 1 -C 4 of the first surface 1 and the second surface 2 are formed with the same shape. Positive lands 11 are formed at the outer perimeters of the first surface 1 and the second surface 2 , and the central sections 1 a , 2 a of the surfaces 1 , 2 are indented. The surfaces 1 , 2 are highest at the corners C 1 -C 4 . The curved ridge line 7 is formed at the intersection between the positive land 11 and the twisted surface 10 formed from sections of the third and fourth surfaces 3 , 4 .
[0043] With this replaceable cutting edge insert 20 A according to this example, the diagonal corners C 2 , C 4 of the first surface 1 and the second surface 2 can be used as cutting edges for a cutter rotating clockwise, while the remaining corners C 1 , C 3 can be used as cutting edges for a cutter rotating counterclockwise. However, since all the corners C 1 -C 4 have the same height (amount of projection), the amount of projection (the amount of projection in the direction of increasing rake angle) for the corners cannot be as great as those for the insert in FIG. 1 . Thus, the rake angle is smaller than that of the insert in FIG. 1 , and a positive axial rake cannot always be guaranteed when installed on the main cutter body. However, this structure will achieve the objects of improving the squareness of the corner and the flatness of the cut wall surface of the workpiece.
[0044] Other aspects of the replaceable cutting edge insert 20 A in FIG. 3 are the same as those of the insert in FIG. 1 , so like numerals are assigned to elements and corresponding descriptions will be omitted.
[0045] FIG. 4 shows a replaceable cutting edge insert 20 B according to a further example. The sections of the third surface 3 and the fourth surface 4 outside of the twisted surfaces 10 are formed from multiple flat surfaces 3 a , 3 b and flat surfaces 4 a , 4 b . The flat surfaces 3 a , 3 b and the flat surfaces 4 a , 4 b intersect at obtuse angles and form humped surfaces when the first surface 1 or the second surface 2 is viewed directly from the front. With this type of shape for the third surface 3 and the fourth surface 4 , a positive face angle κ′ can be applied with an approach angle Ψ of 0 deg without having the fifth and sixth surfaces 5 , 6 formed as humps. Other aspects of the replaceable cutting edge insert 20 B in FIG. 4 are the same as those of the insert in FIG. 1 , so overlapping descriptions will be omitted.
[0046] FIG. 5 shows a replaceable cutting edge insert 20 C according to a fourth example, in which the ridge line 7 is formed as a linear ridge line that is bent at an intermediate position. A linear ridge line will be somewhat shorter than a curved ridge line, but a main cutting section that is formed as a linear ridge line will provide advantages that are not significantly different from those provided by a structure in which the main cutting section is formed as a curved ridge line. Other aspects of the structure are the same as those of the replaceable cutting edge insert 20 b in FIG. 4 .
[0047] The replaceable cutting edge insert 20 in FIG. 1 and the replaceable cutting edge inserts 20 A, 20 B, 20 C of FIG. 3 through FIG. 5 are all shaped so that the outline shape does not change when turned 180 deg along the horizontal plane. Also, when the insert is inverted around a bisecting line L that bisects along the height axis of the first surface 1 (see FIG. 3A ), the outline of the first surface 1 and the second surface 2 do not change after inverting. Thus, the two diagonal corners of the first surface 1 and the two diagonal corners of the second surface 2 can be used as cutting edges by rotating the structure. Also, the inserts 20 A, 20 B, 20 C in FIG. 3 through FIG. 5 can be mounted on a cutter that is rotated in reverse so that the remaining two corners of the first and second surfaces can be used as cutting edges. Thus, while all the inserts can be economically advantageous, it is possible to have different shapes for the first surface 1 and the second surface 2 , the third surface 3 and the fourth surface 4 , and the fifth surface 5 and the sixth surface 6 . Regardless of whether there are many or fewer usable corners, the present invention improves the squareness of cut corners.
[0048] FIG. 6 through FIG. 9 show an example of a corner milling cutter that uses an insert with replaceable cutting edge according to the present invention. In this corner milling cutter 30 , the replaceable-blade cutting insert 20 from FIG. 1 is mounted on a base 32 provided at the outer perimeter of the end of a main cutter body 31 .
[0049] In the replaceable cutting edge insert 20 , the first surface 1 forms a rake face, the twisted surface 10 and the third surface 3 form an outer perimeter flank face, the fifth surface 5 forms a front flank face, the ridge line 7 between the first surface 1 and the third surface 3 forms the main cutting section, the ridge line 8 between the first surface 1 and the fifth surface 5 forms the secondary cutting section. The insert is oriented so that the axial rake γp is +5 deg, the radial rake γf is −15 deg. The approach angle Ψ is 0 deg and the face angle κ′ is 15′.
[0050] The replaceable cutting edge insert 20 is secured to the main cutter body 31 using a clamp screw 33 passed through an attachment hole 12 . The insert of this example is formed with the attachment hole 12 (see FIG. 1 through FIG. 5 ), which extends from the third surface 3 to the fourth surface 4 . The clamp screw 33 (see FIG. 6 , FIG. 7 ) is passed through the attachment hole 12 , and the clamp screw 33 is screwed radially into the main cutter body 31 to and is secured to the main cutter body 31 (see FIG. 6 through FIG. 10 ). However, if space is available, it is also possible for the attachment hole 12 to be extended from the first surface 1 to the second surface 2 , with a clamp screw being passed through the attachment hole and being tightened and secured in a direction perpendicular to the cutter radius.
[0051] FIG. 10 shows the present invention used in a cutter with seven blade. As show here, the corner milling cutter can be set up for any number of blades and is not restricted to the four blades as shown in FIG. 6 through FIG. 8 . | A replaceable-blade cutting insert for corner milling cutters has a first and second surface; a third and fourth surface connected to a first side edge and a second side edge thereof respectively; and a fifth and sixth surface connected to a first edge and a second edge of the first surface and the second surface respectively. The first surface is used as rake face, the third surface is used as an outer perimeter flank face, and the fifth surface is used as a forward flank face. A twisted surface is disposed on a section of the third surface, forming a ridge line that acts as a main cutting edge intersecting with the first surface and interposed between the third and first surface. The first and second surface can be positioned with a height offset relative to each other so that at least one set of diagonal corners are projected. | 8 |
FIELD OF THE INVENTION
The present invention relates to improved mounting mechanisms for gun sights for small arms which provides for simple and easy replacement.
BACKGROUND OF THE INVENTION
Conventional gun sight attachments in the form of “dove tail” joints are generally employed in semiautomatic pistols and other small arms. Dove tail joints are usually machined in the pistol slide transverse to the gun axis, providing clamping of the sight in vertical direction with the sight prevented from lateral and transverse movement by the contact of the dove tail walls. This arrangement, while providing a solid coupling between the pistol slide and the annexed sight, is expensive because of the required close tolerances. Furthermore, such dove tails require special tools to assemble and disassemble the sights. Should the machined tolerances be inadequate, the shocks and vibrations of shooting inevitably will lead to the loosening and possible failure of attachment.
It is the object of the present invention to provide a gun sight attachment mechanism which makes the sight simple to assemble with and to disassemble from the pistol, with no special tools or skills required. The new mechanism is very simple, inexpensive, and permits alternative materials such as plastics to be employed for the gun sights. The new mechanism uses detent balls which lockingly register with sockets formed in the slide when engaged by a sliding lock pin. Detachment is achieved by removal of the lock pin.
For a more complete understanding of the present invention and its attendant advantages, reference should be made to the drawings in conjunction with the detailed description of the invention.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial perspective view of the front portion of a pistol slide having a front sight dovetail slot formed therein;
FIG. 2 is a perspective view of a front sight bar having hollow passages formed therein to receive a locking pin and spherical detents for mounting the front sight to the slide;
FIG. 3 is a perspective view of the front sight in the slide prior to insertion of the locking pin;
FIG. 4 is a cross-sectional view taken along line 4 - 4 of FIG. 3 ;
FIG. 5 is a cross-sectional view taken along line 5 - 5 of FIG. 3 ;
FIG. 6 is a perspective view of a rear sight having the detent lock of the invention adapted for mounting a rear sight on a multi-notched rear portion of a pistol slide;
FIG. 7 is a cross-sectional view taken along line 7 - 7 of FIG. 6 ;
FIG. 8 is a top plan view of the rear sight of FIG. 6 .
DETAILED DESCRIPTION OF THE INVENTION
The gun sight mount of the invention includes a dove tail seat 10 formed on the front end of a pistol slide 11 provided with two lateral sockets 12 , 13 machined in the shape of half cylinders to engage and retain the two steel detent balls 14 , 15 , and a back rest surface 16 . A front bar sight 17 includes a transverse, cylindrical ball retention aperture 18 , a longitudinal, axial, cylindrical channel 19 for reception of a locking pin 20 (solid pin or spring pin) and a rear access aperture 21 for insertion of a punch or a like simple tool for engaging and expelling the locking pin 20 . The steel detent balls 14 , 15 when engaged in their respective sockets 12 , 13 secure the front sight bar to the slide by a detent action.
In accordance with the principles of the invention, the special dove tail seat 10 , though somewhat similar in shape to a conventional dove tail groove, does not require tight machining tolerances. The retaining of the gun sight 17 in place is not provided by the friction generated by the dimensional interference between conventional dove tail groove and sight, but rather by the ball detents 14 , 15 engaging both in the sight 17 and in the dove tail seat. The sight 17 , with the two detent balls inside in the ball retention aperture 18 , is slidingly inserted in the dove tail seat 10 until it stops against the back rest surface 16 . At this point, the sight 17 , with the sockets 12 , 13 perfectly aligned with the ball retention aperture 18 , is ready to be secured in place by the insertion of the locking pin 20 in the longitudinal channel 19 and the consequent camming engagement with balls 14 , 15 to cause a lateral shift of the balls 14 , 15 into the sockets 12 , 13 ( FIG. 3 ). Importantly, the sight 17 is kept firmly secured, with no play or looseness, by the locking pin 20 engaging the steel balls 14 , 15 , as well as the bottom surface 9 of the dove tail seat 10 and the sight 17 . Alternatively, if a spring pin rather than a solid pin is employed as the locking pin 20 , the elastic compression of the spring will contribute to the locking of the sight to the slide. Escape of the locking pin, under the impact of the slide against the frame, is prevented by the rear access aperture 21 being of smaller diameter than that of longitudinal channel 19 . Disassembly is obtained by expelling the locking pin 20 from the channel 19 by a punch or similar tool inserted in the access aperture 21 permitting the detent balls 14 , 15 to retract from the sockets 12 , 13 into the channel 19 so that the unlocked sight bar 17 may be slid forwardly out of the dove tail slot 10 .
The advantages of the new front sight mounting mechanism include easy assembly and replacement of the sight without special skills or special tools, a hammer and punch being the only tools needed. Given the innovative mechanical retaining system, free of previously required tight tolerances and previously required related hard compression and stress of the two coupled parts (sight and dove tail), alternative comparative inexpensive materials for the sights, such as plastics, may be employed. Moreover, an assortment of sights, providing any desired different settings of the line of sight in windage and elevation, may be provided at low cost.
The principles of the invention may be adapted to usage in mounting a rear sight 30 having U-shaped sighting notch 29 and dovetail base 28 adapted to mate with transverse notch 27 . With reference to FIGS. 6-8 , a traditional transverse dove tail rear sight 30 is modified by machining a series of half-notches or sockets 31 - 35 each capable to receive a steel detent ball 36 inside the profile of the sight ( FIG. 6 , position 1 ). An equal number of half-notches or sockets 41 - 45 in the shape of hemispherical cavities are machined in the sight seat 38 , along the back edge 39 of the dove tail. The sockets 41 - 45 are differently spaced than the notches 31 - 35 in the sight. They are machined with a different pitch as shown in the top view of FIG. 8 . Specifically, central notch 33 of the sight is placed on the central axis of the sight while the central notch 43 of the seat is placed on the mid plane of the gun. The coincident location of notches 33 , 43 is shown in FIG. 8 , and represents a perfectly centered position of the sight with respect to the gun axis.
The different location of the notch 42 on the sight seat with respect to the corresponding notch 32 on the sight shifts the rear sight slightly to the right, when the two notches 32 , 42 are assembled in registry. Similarly, notch 41 , provides an increased shift to the right. Notch positions 44 and 45 are symmetrical with those of notches 42 , 41 and provide for corresponding shifts to the left. In the illustrated mounting, there are five different selectable windage settings: two on the right, two on the left, plus the central “zero” position; however, it will be understood that variations may be obtained through different cylindrical arrangements of ball/notch diameter and position as may be desired. The rear sight can be kept firmly in place by insertion of a locking (or spring) pin 50 into transverse channel 52 , to cam the steel ball 36 out from position 1 to position 2 ( FIG. 7 ). The “multi notch” rear sight brings in the whole advantage of the steel ball detent system such as easy assembly/replacement (plus adjustability) and inexpensive construction due to the tight tolerance relief.
It should be understood, of course, that the specific form of the invention herein illustrated and described is intended to be representative only, as certain changes may be made therein without departing from the clear teachings of the disclosure. Accordingly, reference should be made to the following appended claims in determining the full scope of the invention. | An improved dove tail sight attachment system utilizing a displaceable spherical element to engage a mating hemispherical socket formed along the edge of a dove tail seat on a pistol slide. | 5 |
FIELD OF THE INVENTION
The present invention relates to a method and apparatus for utilizing tar sands having a broad range of bitumen content and which rapidly pyrolyzes tar sands to produce oil and other hydrocarbon products.
BACKGROUND OF THE INVENTION
A major effort to recover the hydrocarbon values from tar sands on a commercial scale was started with the official opening of the great Canadian oil sands plant in 1967. A great deal of research and experimentation preceded this event and research efforts are still continuing. The ultimate objectives of the research have been to improve the quality and quantity of the recovered hydrocarbon products and to improve the environmental acceptance of the overall process.
Processes for recovering oil from carbonaceous material such as oil shale have existed for some time. One such process is described in U.S. Pat. No. 4,340,463 (Harak) issued July 20, 1982. In this patent a system is provided for utilizing fines of carbonaceous materials to obtain the maximum utilization of the energy content of the fines and produce a waste which is relatively inert and of a size to facilitate disposal. The process involves employing a cyclone retort which pyrolyzes the fines in the presence of heated gaseous combustion products. The cyclone retort has a first outlet through which vapors can exit that can be cooled to provide oil and a second outlet through which spent shale fines are removed. A burner connected to the spent shale outlet of the cyclone retort burns the spent shale with air to provide hot combustion products that are carried back to the cyclone retort to supply gaseous combustion products used therein. The burner heats the spent shale to a temperature at which it forms a molten slag and the molten slag is removed from the burner into a quencher that suddenly cools the molten slag to form granules that are relatively inert and of a size that is convenient to handle for disposal in the ground or in industrial processes.
This oil shale process, however, suffers from several drawbacks. First, the gases produced by this process are diluted with combustion products and thus their heating value is much reduced. Second, this process lacks the flexibility necessary for hydrocarbon recovery from tar sands because tar sands of different types will have a broad range of bitumen content. Thus, there is a need for a process which does not dilute the hydrocarbon gases produced with combustion products and which is capable of utilizing tar sands having a broad range of bitumen content.
SUMMARY OF THE INVENTION
A first embodiment of the present invention relates to an apparatus for utilizing tar sands having a broad range of bitumen content. The apparatus includes a cyclone retort chamber having an inlet for receiving tar sands and hot gases, a means for circulating tar sands around the retort chamber whereby the tar sands are maintained in a fluidized state with hot gases, a gas outlet for removing gases from the chamber and a spent sand outlet for removing spent sand material from the chamber. The apparatus also includes a burner for burning the spent sand material to generate gaseous combustion products. The burner has an inlet coupled to the spent sand outlet of the retort chamber and an outlet for removing gaseous combustion products therefrom. Finally, the apparatus includes heat exchange means having a first inlet coupled to the cyclone retort chamber gas outlet and a second inlet coupled to the burner outlet. The heat exchange means also includes a first outlet coupled to the cyclone retort chamber inlet and a second outlet for removing cooled gaseous combustion products. The heat exchange means is connected such that at least some of the gases removed from the cyclone retort chamber are heated by heat exchange with the gaseous combustion products from the burner and are fed back to the cyclone retort chamber.
In a second embodiment, the present invention relates to a method for utilizing tar sands to form hydrocarbon products. In the method, the tar sands are pyrolyzed with hot gases in a cyclone retort chamber by maintaining the tar sands circulating around the chamber in a fluidized state with hot gases. Gases are removed from the retort chamber and the spent sand is also removed from the retort chamber. The removed gases are cooled to recover oil and hydrocarbon products therefrom. The removed spent sand is burned in a cyclone-type burner to generate hot combustion gases and to heat the spent sand to a high temperature of approximately 2,000° F. The hot combustion gases are also removed from the burner and are used for heat exchange with a fraction of the gases removed from the retort chamber to thereby heat the gases from the retort chamber. Finally, the cooled combustion gases are discarded and the heated fraction of the gases removed from the retort chamber are fed back into the cyclone retort chamber along with additional tar sands.
It is the primary object of the invention to provide a relatively rapid pyrolysis process which will utilize tar sand having a broad range of bitumen content.
It is further object of the present invention to pyrolyze tar sands to produce hydrocarbon gases which are not diluted with combustion products.
It is a still further object of the present invention to produce, from tar sands, hydrocarbon gases which have a high heating value.
It is a still further object of the present invention to provide discharge sand which has the char or carbonaceous residue completely burned off to thereby minimize environmental problems associated with disposal of the spent sand.
These and other objects of the present invention will be apparent to one of ordinary skill in the art from the detailed description which follows.
BRIEF DESCRIPTION OF THE DRAWING
The single FIGURE is a diagrammatic view of a preferred embodiment of a system for utilizing tar sands in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention relates to a system for utilizing tar sand having a broad range of bitumen content. A detailed description of the composition of tar sands can be found in an article entitled "Great Canadian Oil Sands Experience in the Commercial Processing of Athabasca Tar Sands", Andrews, G. F. and Lewis, H. M., American Chemical Society, Division of Fuel Chemistry, volume 12, number 1, 1968, which is hereby incorporated by reference.
The single FIGURE illustrates a system for utilizing tar sands to produce oil and other fossil-derived products and to provide energy that can be utilized on site. For example, the tar sands produce energy which can be used to generate electrical power. Further, the tar sands produce an essentially inert and uniform-sized waste that can be easily disposed of either in the ground or can be utilized in industry.
The system includes a tar sand inlet 11 for feeding tar sands into a heat exchanger 13. From heat exchanger 13, the tar sands are fed to pyrolysis cyclone retort 15 through cyclone inlet 17 by line 19. Also connected to line 19 is gas line 21 for providing hot, substantially non-oxidizing gases to line 19 that provide the heat to enable operation of cyclone retort 15. By substantially non-oxidizing gases, it is meant gases having very little and preferably no free oxygen present to oxidize the tar sand products in cyclone retort 15. Cyclone retort 15 also includes gas outlet 23 for removing gases from cyclone retort 15 and sand outlet 25 for removing spent tar sands from cyclone retort 15. The tar sands and hot gases enter cyclone retort 15 where the heat of the gases heat the tar sands to rapidly pyrolyze them. The reaction releases a gas-oil mist as well as spent tar sands all of which exit cyclone retort chamber 15 through gas outlet 23. The larger pyrolyzed sand granules drop to the bottom of cyclone chamber 15 and are removed through sand outlet 25.
The spent sand which passes through sand outlet 25 is fed to a cyclone furnace or burner 29 through line 27 where it is burned with air which enters line 27 from line 33. The air is fed through air inlet 35 to line 37 and thence to heat exchanger 39 where it is heated by heat exchange with the gases removed from cyclone retort chamber 15 through gas outlet 23 and line 41. These gases, removed from cyclone retort chamber 15, are fed through line 41 to heat exchanger 43 where they are cooled in contact with recycle-gas. The gases removed from cyclone retort chamber 15 exit heat exchanger 43 through line 45 which leads to heat exchanger 39 wherein they are further cooled by heat exchange with air and additional gases. From heat exchanger 39, the gases removed from cyclone retort chamber 15 continue through line 47 to heat exchanger 49 where they are still further cooled to room temperature by heat exchange with water fed through water inlet 51. Finally, the gases removed from cyclone retort chamber 15 leave heat exchanger 49 through line 53 which feeds them to separator 55 wherein the condensed liquids are separated from the remaining gases. The condensed liquids leave separator 55 through outlet 57, and oil is among the condensed liquids. The remaining gases leave separator 55 through outlet 59. Part of the gas stream exiting through outlet 59 is used as recycle-gas by being fed to line 61. The remainder of the gases leaving through outlet 59 are taken off as product gases through product outlet 63.
The recycle gas in line 61 is then further divided into two streams which are both heated by heat exchange. The first stream passes through line 37 where it is mixed with air and fed to heat exchanger 39 where it is heated by heat exchange with the gases removed from cyclone retort chamber 15. This heated mixture of recycle-gas and air then proceeds into line 65 which feeds it to heat exchanger 67 which further heats the air and recycle gas mixture. Finally, the air and recycle-gas mixture leaves heat exchanger 67 through line 69 by which it is fed to heat exchanger 71 wherein the mixture is further heated by heat exchange with combustion products from burner 31. The heated air and recycle-gas mixture leaves heat exchanger 71 through line 33 and is then mixed with spent tar sands in line 27 and fed to burner 31 where the tar sands are burned at a relatively high temperature of about 2,000° F. which substantially completely oxidizes all organic material in the spent tar sands.
As a result of burning the spent sand and supplementary fuel, ash is generated at a high temperature. This granular, high-temperature ash leaves burner 31 through outlet 85 where it is fed through line 87 to heat exchanger 77 to begin cooling of the ash. The ash is cooled in heat exchanger 77 by heat exchange with a portion of recycle-gas from line 61 which is fed through line 73 to heat exchanger 43 wherein the recycle-gas is first heated by contact with gases removed from cyclone retort chamber 15. The partially heated recycle-gas is then fed from heat exchanger 43 through line 75 to heat exchanger 77 where it serves to cool ash from burner 31. The partially cooled ash is then fed from heat exchanger 77 through line 89 to heat exchanger 67 wherein it is further cooled by heat exchange with the air and recycle-gas mixture from line 65. Finally, the partially cooled ash is fed from heat exchanger 67 through line 91 to heat exchanger 93 where it is cooled to its final temperature by heat exchange with cooling water fed through water inlet 51. The cooling water used for heat exchange in heat exchanger 93 has already been partially heated in heat exchanger 49 by heat exchange with gases removed from cyclone retort chamber 15 and this water is fed from heat exchanger 49 to heat exchanger 93 through line 95. The completely cooled ash leaves heat exchanger 93 through line 97. This ash has all of the char burned off and thus most, if not all, of the environmental problems related to disposal of this ash are eliminated.
Gaseous combustion products or flue gases leave burner 31 through outlet 79 and are fed through line 81 to heat exchanger 83 wherein they are cooled by heat exchange with recycle-gases from heat exchanger 77 which are fed to heat exchanger 83 through line 99. The heated recycle-gas then proceeds from heat exchanger 83 to line 21 and is fed back into cyclone retort chamber 15 through inlet 17 along with fresh tar sands. The partially cooled combustion gases from heat exchanger 83 are then fed through line 101 to heat exchanger 71 for further heat exchange with the air and recycle-gas mixture in order to further cool the combustion gases. From heat exchanger 71, the combustion gases are fed through line 103 to heat exchanger 105 for final cooling in contact with water from heat exchanger 93 which is fed through line 107 to heat exchanger 105. Not all the water from heat exchanger 93 is necessary for cooling the combustion products in heat exchanger 105 and thus some of the water is removed through water outlet 109 and may be used for other purposes. The cooled combustion products are finally removed from heat exchanger 105 through outlet 111. The remaining steam is passed from heat exchanger 105 through line 113 back to heat exchanger 13 to heat the incoming tar sands prior to feeding the tar sands to pyrolysis cyclone chamber 15. The partially cooled steam exits heat exchanger 13 through line 115 and is divided into a water component which exits through outlet 117 and steam component which exits through outlet 119.
A typical example of a cyclone retort chamber 15 is shown in FIG. 2 of U.S. Pat. No. 4,340,463 issued on July 20, 1982, which is hereby incorporated by reference.
The present invention provides a processing sequence for processing tar sands based on operations that have been used successfully in industry for the generation of hot gases, or for high temperature rapid reactions of solids with gases. The equipment, heat exchangers, phase separators, and feeders are standard units used in industry. The present invention improves the recovery of hydrocarbon products by producing a gas stream that is not diluted by combustion products and improves the environmental acceptability of the waste products by removing the carbonaceous material from the sand before it is discharged and disposed of.
The spent tar sand containing carbonaceous residue or char is fed from the pyrolysis cyclone retort chamber 15 to burner 31 where it is burned at about 2,000° F. with air and preheated by heat exchange with hydrocarbon products, sand and combustion products. Depending upon the bitumen content of the tar sands being process, additional fuel may be required to supply the energy needs of the process. For example, for tar sands containing 6.0 weight percent bitumen, all of the product gas and part of the product oil must be burned to supply the energy needs of the process. The relative amounts of product gas and oil being burned could be adjusted if there was an economic requirement for the production of additional gas. For a 9.5 weight percent bitumen content in the tar sands, less than half of the product gas would need to be burned to supply sufficient energy for the process. For tar sands containing 14.14 weight percent bitumen, such as that found in the Athabasca tar sands, the char provides more than enough energy for the process.
The cyclone retort chamber operates on a cyclone principle, wherein the tar sands and recycle-gases enter tangentially to move in a spiral through the retort chamber 15, to keep the tar sands suspended in the recycle-gases. This cyclone process helps avoid the formation of clinkers which can occur in other retorts as a result of the fusing together of small particles. Furthermore, according to the present invention, a retort chamber which is relatively small in size is adequate because the pyrolysis occurs rapidly. The cyclone retort enables such pyrolyzing to be performed with relatively small particles that can be suspended in a rapidly moving gas stream, including relatively large particles of up to about 1/2-inch size as well as small particles.
The following example is provided to illustrate a specific embodiment of the present invention.
EXAMPLE 1
This example provides all process parameters for oil and gas production from a tar sands charge containing 9.5 weight percent bitumen. The table below indicates all of the process parameters to generate 3,000 bbl/day of oil from tar sands having 9.5 weight percent bitumen content.
TABLE 1______________________________________ Feed Streams Amount, lb/hr Type______________________________________11 620,925 Tar Sands35 156,803 Air51 212,343 Water______________________________________ Product Streams Amount Type______________________________________63 6,439 Product Gas57 41,527 Liquid Oil97 561,938 Sand (Ash)109 118,803 Water111 167,825 Combustion Products117 1,631 Water119 91,909 Steam______________________________________Temperatures at Various Points in Process Stream Temperature, °F.______________________________________11 7715 1,02219 27821 1,99627 1,02231 2,00033 1,99035 7737 7741 1,02245 40747 29751 7753 7757 7761 7763 7765 40369 1,03373 7775 99981 2,00087 2,00089 1,03391 84395 19097 19099 1,994101 1,994103 1,102107 212109 212111 473113 900115 212117 212119 212______________________________________ Tar Sands Properties______________________________________Tar Sands Charge 620,925 lb/hrBitumen Content 9.5 wt. %Potential Oil Yield 3,000 Bbl/dayPotential Gas Yield 11,857 lb/hrPotential Char Yield 5,604 lb/hr______________________________________ Process Results______________________________________Char Burned 5.604 lb/hrOil Burned 0Gas Burned 5,418 lb/hrOil Produced 45,527 lb/hr or 3,000 Bbl/dayGas Produced 3,439 lb/hrH.sub.2 S Free Gas Produced 83,639 scf/hrDischarged Sand Ash 561,938 lb/hr______________________________________
EXAMPLE 2
This example is based on tar sands having a bitumen content of 6.0 weight percent.
______________________________________ Tar Sands Properties______________________________________Bitumen Content 6.0 wt %Tar Sands Charge 983,132 lb/hrPotential Oil Yield 3,000 Bbl/dayPotential Gas Yield 11,857 lb/hrPotential Char Yield 5,604 lb/hr______________________________________ Process Results______________________________________Char Burned 5,604 lb/hrOil Burned 2,341 lb/hrGas Burned 11,855 lb/hrOil Produced 39,187 lb/hr or 2,831 Bbl/dayGas Produced 0H.sub.2 S Free Gas Produced 0Discharged Sand Ash 924,144 lb/hr______________________________________
EXAMPLE 3
This example is based on tar sands having a bitumen content of 14.14 weight percent.
______________________________________ Tar Sands Properties______________________________________Bitumen Content 14.14 wt %Tar Sands Charge 417,171 lb/hrPotential Oil Yield 3,000 Bbl/dayPotential Gas Yield 11,857 lb/hrPotential Char Yield 5,604 lb/hr______________________________________ Process Results______________________________________Char Burned 5.604 lb/hrOil Burned 0Gas Burned 0Oil Produced 41,527 lb/hr or 3,000 Bbl/dayGas Produced 11,856 lb/hrH.sub.2 S Free Gas Produced 154,007 scf/hrDischarged Sand 358,183 lb/hr______________________________________
Although particular embodiments of the invention have been described and illustrated herein, it is recognized that modifications and variations may be made by those of ordinary skill in the art and consequently, it is intended that the claims define the scope and content of the invention. | A method and apparatus for utilizing tar sands having a broad range of bitumen content is disclosed. More particularly, tar sands are pyrolyzed in a cyclone retort with high temperature gases recycled from the cyclone retort to produce oil and hydrocarbon products. The spent tar sands are then burned at 2000° F. in a burner to remove residual char and produce a solid waste that is easily disposable. The process and apparatus have the advantages of being able to utilize tar sands having a broad range of bitumen content and the advantage of producing product gases that are free from combustion gases and thereby have a higher heating value. Another important advantage is rapid pyrolysis of the tar sands in the cyclone so as to effectively utilize smaller sized reactor vessels for reducing capitol and operating costs. | 2 |
BACKGROUND OF INVENTION
1. Field of the Invention
This invention relates to composite superconductors, and more particularly to composites comprising high field superconductors of the A-15 crystal structure type.
2. Description of Prior Art
Superconducting materials are those materials which exhibit zero resistance when the temperature of the material is lowered below some critical temperature level. At this critical temperature the material undergoes a transition from the normal to the superconducting state. The temperature at which this transition takes place is exceedingly important, that is, a high critical temperature is very desirable.
Another important superconducting property is that the material should have a high critical current. That is, the maximum current carried before a measurable voltage first appears in the superconducting material must be high.
Therefore, materials which exhibit a high critical temperature, a high critical field and a high critical current are preferred superconductors. Such materials are intermetallic compounds of the A-15 crystal structure including Nb 3 Sn; Nb 3 Ga; V 3 Ga; Nb 3 Al and Nb 3 Ge. The principal difficulty with these materials that has inhibited their acceptance is their inherent brittleness, that is, they easily fracture when stressed. A superconductor must be capable of being wound into a solenoid without subsequent deterioration in its properties, such as would occur if the superconductive compound would fracture during winding.
Composite superconductors of the A-15 type have been made of niobium-tin in the form of a tape. A thin deposit of Nb 3 Sn is placed onto a supporting metallic substrate so that the composite structure can be stressed without damage to the superconductor. This can be accomplished by vapor deposition and by diffusion.
In vapor deposition a mixture of gaseous niobium and tin chlorides are deposited on a hot stainless steel strip. By proportioning of the chlorides the deposit will consist of Nb 3 Sn.
In the diffusion process an initial layer of tin of a specific predetermined thickness is formed on a niobium strip and the resulting laminate is treated at 1000°C to form Nb 3 Sn by reaction between the tin and niobium.
The Nb 3 Sn composite is then stabilized by laminating it between layers of OFHC copper thereby producing a laminated conductor having superconductive material surrounded by normal material. The high thermal conductivity and high electrical conductivity of the copper provides a protective current shunt in the event that the superconductor should momentarily transform from the superconducting to the normal state.
Aside from the inherent brittleness of tapes comprising an intermetallic compound, the geometry of the product was such that compact, stabilized coils could not be wound. Furthermore, intrinsically stable conductors are generally twisted about a central axis with a pitch of a few inches. This can easily be accomplished in composite filaments of 0.01 - 0.05 inches in diameter, however it is far more difficult to impart such a pitch to a tape of say 0.5 inches wide by 0.01 inches thick.
Recently multifilament A-15 type superconducting wire has been introduced as an alternate to the A-15 tape hereinbefore described. As set forth in British Pat. Spec. No. 1,280,583 a method is disclosed for making multifilament composite superconductors of the A-15 type.
The disclosed method overcomes one of the principal disadvantages of superconductive tapes consisting of intermetallic compounds, namely brittleness. In this method rods of pure niobium are inserted into a solid copper-tin alloy matrix or into a particle mass of copper and tin powders. The assembly is then mechanically worked to fine wire. The initial rods are now filamentary strands that are converted into a superconductive compound by heating the wire at 773.9°C (1425°F) for about 96 hours. This heat treatment permits niobium and tin to react and form Nb 3 Sn on the periphery of the filaments.
Although this method produces satisfactory multifilament Nb 3 Sn we have found that the overall superconducting properties to be less than satisfactory. As we have previously indicated a stabilized superconductor must have a quantity of high purity normal material interposed in the conductor to act as a shunt in the event the conductor transforms from the superconducting to the normal states. High purity copper, silver and aluminum can be used. These materials exhibit high electrical and thermal conductivities. It is well known in the art that conductivity of the normal material can be seriously degraded by the slightest amount of contamination.
To stabilize a multifilament superconductor as taught by the aforementioned British Specification, high purity (OFHC) copper rods could be inserted into the copper-tin matrix or a copper sheath could be used as a jacket for the assembly. The conductivity of the copper would not be affected during mechanical working down to fine wire. However, once the high temperature heat treatment starts tin will not only diffuse into the niobium filaments to form Nb 3 Sn; it will also diffuse into the high purity copper thereby destroying the thermal and electrical conductivity of this material. The final product will not be a stabilized superconductor.
SUMMARY OF INVENTION
In accordance with our invention, as hereinafter more fully described, we form a composite superconductor containing at least a single fine filament with a periphery of an A-15 Type II superconductive compound, high purity normal material for stabilization of the superconductor and an impervious barrier layer. This is accomplished by forming a composite containing a first metallic component of an A-15 Type II superconductive compound, a bronze alloy that contains a second metallic component which is capable of reacting with the first metallic component so as to form a superconductive compound, high purity normal material for stabilizing the composite, and an impervious metallic barrier layer interposed between the normal material and the bronze alloy.
After the composite is assembled it is mechanically worked from a relatively large diameter of about 2 inches to 10 inches to a wire size of about 0.1 to 0.008 inch diameter. Conventional working may be employed such as an initial high temperature extrusion, intermediate wire drawing and finally fine wire drawing. When the desired wire diameter is obtained a carefully controlled heat treatment is performed. The wire is heated to a temperature to cause the first metallic component and the second metallic component contained in the bronze alloy to diffuse and react with each other to form the desired superconductive compound on the periphery of one of the components.
The thermal and electrical conductivity of the normal material is not impaired by diffusion of the first or second metallic component into it. The purity of the normal material is maintained by the placement of an impervious barrier layer between it and the bronze alloy. This layer insures that diffusion into the normal material is prevented.
A stabilized high-field superconductor with an A-15 type compound can be obtained by this invention. The superconductive compound is produced after the final wire diameter is obtained by a high temperature heat treatment. Contamination of the high purity normal material is prevented by incorporating an impervious barrier layer into the superconductor. This layer must be placed in such a position so as to prevent diffusion of a metallic component into the normal material.
In a particular embodiment of the present invention, the barrier layer takes the form of an annular shell comprising sectors of at least two different metallic materials. One of these sectors is adapted to react with a component of the bronze alloy under the final high temperature heat treatment to form a superconducting layer. The other sector is substantially non-reactive with the surrounding materials. Thus, a discontinuous ring of superconductor is formed which substantially prevents flux trapping tending to impair the performance of the superconducting composite.
Accordingly, it is an object of this invention to provide an improved method of making stabilized high-field superconductors.
It is a further object of this invention to provide a method of making a stabilized high-field multifilament superconductor of an A-15 type.
Still a further object of this invention is to provide a method of making a stabilized high-field superconductor of an A-15 type containing high purity normal material by heat treating a composite wire without contaminating the normal material.
Another object of this invention is to provide a stabilized multifilament high-field superconductor of the A-15 type.
Still a further object of this invention is to provide a composite superconductor that contains a barrier layer for preventing contamination of high purity normal material employed for stabilization.
A more specific object of the invention is to form an annular barrier layer which reacts to form a discontinuous superconducting ring which prevents flux trapping in the composite.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a cross-sectional view of a composite of this invention.
FIG. 2 is a cross-sectional view of the composite of FIG. 1 after the same has been heat treated to form a superconductive compound.
FIG. 3 is a cross-sectional view of a composite of another embodiment of this invention.
FIG. 4 is a cross-sectional view of the composite of FIG. 3 after the same has been heat treated to form a superconductive compound.
FIB. 5 is a cross-sectional view of a composite showing another embodiment of this invention.
FIG. 6 is a cross-sectional view of the composite of FIG. 5 after the same has been heat treated to form a superconductive compound.
FIG. 7 is a cross-sectional view of a composite showing another embodiment of this invention, comprising a barrier layer in the form of an annular shell formed from sectors of at least two different metallic materials.
FIG. 8 is cross-sectional view of the composite of FIG. 7 after the same has been heat treated to form a discontinuous annular ring of superconducting material.
FIG. 9 is a cross-sectional view of a composite showing another embodiment of this invention.
FIG. 10 is a plot showing a micro-probe line scan performed on superconducting wire of this invention.
DESCRIPTION
FIGS. 1, 3, 5 and 7 show in cross-section various configurations that illustrate superconducting composites of this invention. FIGS. 2, 4, 6 and 8 show the configurations of FIGS. 1, 3, 5 and 7 after a high temperature heat treatment has formed a superconductive compound of the A-15 crystal structure. These figures will now be discussed in more detail.
FIG. 1 shows a composite 10 with an annular outer shell 12 of a normal material. OFHC (oxygen free high conductivity copper), aluminum, gold, or silver may be employed. For obvious economic considerations, OFHC copper or aluminum are usually employed. A barrier layer 14 is placed adjacent to the normal material.
The selection of barrier layer materials is critical. The barrier layer must form a continuous impervious obstruction; it must be pure so as not to contaminate the high purity normal material; and it also must be ductile in order to permit co-reduction with the other materials of the composite. Suitable barrier layer materials for this configuration include tantalum, molybdenum and alloys thereof.
A bronze alloy matrix 16 is placed within the barrier layer. This matrix is typically copper alloyed with a predetermined amount of tin or gallium. The specific alloying element employed is determined by the desired superconductive compound. For instance, if the compound is to be Nb 3 Sn, tin will be alloyed with copper. In a like manner, if V 3 Ga is the desired superconductive compound, gallium will be alloyed with copper.
The matrix is provided with a plurality of longitudinally extending parallel bores. Metallic rods 18 are inserted into these bores thereby completing the composite. These rods are of a material which is capable of combining with the alloying element of the matrix so as to form the desired superconductive compound. If Nb 3 Sn is the desired compound niobium rods 18 would be inserted into a bronze matrix containing tin as the alloying element. Likewise if V 3 Ga is the desired compound vanadium rods 18 would be inserted into a bronze matrix containing gallium as the alloying element.
FIG. 2 shows a superconductive compound 19 formed on the periphery of metallic rods 18. This compound can be either Nb 3 Sn or V 3 Ga depending upon the selection of the matrix alloying element and the metallic rod insert.
After composite 10 has been assembled it is mechanically worked by techniques well known in the art, such as extrusion and drawing to a fine wire size. The working is performed at a temperature below that which appreciable diffusion between the component contained within the bronze and the metallic rod takes place. After the composite has been reduced to the desired cross-section it is heated to a temperature at which an appreciable amount of diffusion will take place within a reasonable period of time. The mechanical properties of the filaments are thought to be related to the ratio of the amount of superconductive compound formed and the filament diameter. By determining the filament size the amount of superconductive compound formed can be controlled. Concentration of tin and gallium in the matrix and the temperature at which the diffusion reaction takes place will also determine the ratio of superconductive compound to the filament diameter.
Diffusion of the tin or gallium within the matrix takes place in all directions. These elements would diffuse in an outward direction toward the normal material 12 without the presence of a barrier layer; and if diffusion into the normal material is permitted, thermal and electrical conductivity would be destroyed. This would result in an unstable superconductor; and the potential benefits of using A-15 superconductive compounds would be negated.
Contamination of the normal material by diffusion of gallium or tin is prevented by the impervious barrier layer 14. This layer effectively obstructs the passage of tin and gallium atoms into the normal material. By positioning the barrier layer between the bronze matrix and the normal material, diffusion of the alloying element contained within the matrix is allowed to proceed only toward the metallic component within the matrix. An additional benefit of this invention is that a lesser amount of the alloying element is needed to alloy with copper since this element is not diluted by diffusion into the normal material. A matrix with a lesser amount of tin or gallium will be more ductile thereby permitting greater reductions-in-area before annealing must be performed to restore ductility.
A variation of the embodiment of FIGS. 1 and 2 can be achieved by mechanically working composite 10 to an intermediate size, for instance approximately 0.375 inches. The wire at this size is formed into a hexagonal cross-section and cut into short lengths, generally equal in length to an extrusion cannister. These short, hexagonal lengths are packed into a copper extrusion cannister. The cannister is then mechanically worked into small diameter wire. This variation produces a wire with a honeycomb network of normal material such as OFHC copper throughout the entire superconductor cross-section. Such a construction provides very good thermal and electrical conductivity from the interior to the exterior of the superconductor.
Referring now to FIGS. 3 and 4, there is shown another composite illustrating this invention.
FIG. 3 shows a composite 20 consisting of a bronze alloy matrix 22. As previously described the matrix can be copper alloyed with tin or gallium depending upon the superconductive compound desired. The matrix is provided with a plurality of longitudinally extending parallel bores. Disposed within said bores are hollow metallic sleeves 24. These elements perform two functions; firstly, they are one of the metallic components of the resultant superconductive compound, and secondly, they also act as barrier layers in the manner as hereinbefore described. Positioned within these sleeves are rods 26 of normal material.
Sleeve 24 can be formed from pure niobium or vanadium. Rods 26 can be formed from any high purity normal material as hereinbefore described.
FIG. 4 shows a superconductive compound 28 formed on the periphery of sleeves 24. This compound can be either Nb 3 Sn or V 3 Ga depending upon the composition of matrix 22 and sleeve 24. Penetration into the normal material is prevented by the sleeves.
Referring now to FIGS. 5 and 6, there is shown another composite illustrating this invention.
FIG. 5 shows a composite 30 consisting of a matrix 32 of normal material. The matrix is provided with a plurality of longitudinally extending parallel bores. Disposed within said bores are hollow metallic sleeves 34. These elements perform as hereinbefore described. Positioned within these sleeves are rods 36 of a bronze alloy.
Sleeves 34 can be formed from pure niobium or vanadium. Rods 36 are of a bronze alloy that furnishes the necessary second metallic component that will combine with a portion of the metallic sleeve thereby producing a superconductive compound.
FIG. 6 shows a superconductive compound 38 formed at the interface between sleeve 34 and rod 36. As hereinbefore described this compound can be either Nb 3 Sn or V 3 Ga. Penetration into the normal matrix by tin or gallium is effectively prevented by sleeve 34 acting in its dual role as a barrier layer.
PREFERRED EMBODIMENT
Referring now to FIGS. 7 and 8, there is shown another composite illustrating a preferred embodiment of this invention.
The composite shown in these figures is essentially the same composite illustrated in FIGS. 1 and 2. A composite 40 consists of annular outer shell 41 of normal material and immediately adjacent thereto is barrier layer 42. In this embodiment the barrier layer can be vanadium or niobium and a small segment 43 of another metallic element such as molybdenum or tantalum. A bronze matrix 44 is placed within the barrier layer. The matrix is provided with a plurality of longitudinally extending parallel bores. Metallic rods 45 are inserted into these bores thereby completing the composite.
FIG. 8 shows a superconductive compound 46 formed on the periphery of metallic rods 45. Since barrier layer 42 is either niobium or vanadium a superconductive compound 47 is also formed on this element. There is an area 48 adjacent the small segment 43 that does not contain any superconductive compound. Therefore, the compound formed on the barrier layer is not a continuous ring and cannot act as a flux trap. Flux trapping impairs the performance of a superconductor and must be avoided.
FIG. 9 shows another composite 50 illustrating this invention. In this embodiment, there is provided a hollow extrusion cannister 51. A series of hexagonal components are then fitted together in a geometrical array on the interior of the cannister.
Hexagonal component 52 consists of a barrier layer 53 and an internal portion 54 of normal material. Hexagonal component 55 consists of a bronze matrix 56 and metallic filaments 57. After composite 50 has been assembled and worked down to a fine wire size a superconductive compound is formed in the manner as hereinbefore described.
If the extrusion cannister is made from a high purity normal material and contamination is to be avoided a barrier layer 58 may be employed.
It should be understood that the selection and proportioning of components is very important. High purity normal materials such as OFHC copper, aluminum, gold and silver may be used. The proportion of gallium and tin in the bronze alloy is significant. Sufficient gallium and tin must be present to form the desired A-15 crystal structure, however, if these elements are present in too large an amount objectionable precipitants may form.
The heat treating cycle must be controlled in order to form a superconductive compound of sufficient thickness to impart satisfactory superconducting properties to the composite but yet maintain a certain amount of ductility in the composite.
SPECIFIC EXAMPLE
A 2 inch bronze extrusion billet approximately 5-3/4 inches long containing 10 weight percent tin was prepared with a machined blunt nose and a recessed rear portion for receiving a bronze cap. 19 holes, 19/64 inches in diameter, 4 inches in length were drilled in the billet.
a. 19 pure niobium rods were inserted into the billet. The billet was evacuated and the bronze cap was electron beam welded onto the billet.
b. The billet was preheated to 676.67°C (1250°F) and extruded to 0.55 inches.
c. The extruded billet was drawn to 0.375 inch wire.
d. The drawn wire was wrapped with a high purity annealed tantalum sheet, approximately 0.010 inch thick. The wrapped wire was inserted into an OFHC tube with an inside diameter slightly greater than 0.375 inch.
e. The OFHC tube was drawn to 0.4 inch and then placed inside a one inch diameter copper extrusion billet, heated to 676.67°C (1250°F) and extruded to 0.4 inch.
f. The extruded billet was drawn to 64 mils. After each 20% reduction in area the wire was annealed.
g. The drawn wire was then heat treated at 700°C (1292°F) for 3 days thereby obtaining a layer of Nb 3 Sn around each niobium filament.
FIG. 10 shows a micro-probe line scan performed on material of this example. This figure shows that area A, the outer copper jacket after the high temperature heat treatment remains essentially pure copper. This means that section B, the tantalum barrier layer, effectively prevented diffusion of tin from the bronze matrix, section C, into the outer copper jacket. It can be assumed that neither copper nor tin is present in section B. To confirm this assumption a point count was conducted in area B by putting the probe's electron beam onto a series of points in this area. There was no signal at any point which would indicate the presence of tin. The fluctuation above and below the line representing zero concentration in section B is a normal background effect for this type of analysis and does not reflect a change in composition. Section C represents the matrix material, section D represents the superconductive compound, and section E represents the core of the niobium filament.
The critical current Ic measured at various magnetic fields for this 64 mil wire at 4.2°K is as follows: 40 kilogauss, Ic = 76 amperes; 50 kilogauss, Ic = 60 amperes, 60 kilogauss, Ic = 46 amperes; 70 kilogauss, Ic = 36 amperes.
To illustrate the effect of pure copper on the stability of superconducting composites the following experiment was performed. The resistance of a Nb 3 Sn multifilament composite, 19 strands of niobium in a bronze matrix was compared to the resistance of the wire of this example at 20°K and room temperature.
The data tabulated in Table I shows that copper in the wire of this invention significantly lowers resistance when measured at 20°K and room temperature. Furthermore, the resistivity ratio of the wire of this invention is more than 23 times greater than the unstabilized superconductor. The use of uncontaminated copper in the wire of this invention will provide a protective current shunt in the event that the superconductor should momentarily transform from the superconducting to the normal state. There is no such assurance with the superconductor utilizing the unstabilized bronze matrix.
______________________________________ Wire Resistance RatioComposite Dia. Resistance Data, Data at Room e R.T.Description (mils) at 20°K Temperature e 20°K______________________________________ R e R e mΩ μΩcm mΩ μΩcm19 filamentsof Niobiumin Bronze 12.5 6 2.4 34.5 13.7 5.75:1Wire ofInvention 64 .0013 0.0135 0.175 1.82 135:1______________________________________
It may, therefor, be seen that the invention provides a stabiliized high-field superconductor and a method of making same.
Various modifications of the invention in addition to those shown and described herein will become apparent to those skilled in the art from the foregoing description and accompanying drawings. Such modifications are intended to fall within the scope of the appendant claims. | A superconducting compound of the A-15 crystal structure type is obtained in a composite by a high temperature diffusion between a first metallic component and a second metallic component contained in a bronze alloy. Stability is achieved by including in the composite a quantity of high-conductivity normal material. Diffusion of the second metallic component into the normal material with a resultant degradation of conductivity of the normal material is prevented by placing an impervious barrier layer between the bronze alloy and the normal material. In a specific embodiment, the barrier layer takes the form of an annular shell comprising at least two sectors of dissimilar metals, one of which reacts with a component of the bronze alloy to form a layer of said superconducting compound, and the other of which is substantially non-reactive. Thus, a discontinuous superconducting ring is formed on the barrier layer which prevents flux trapping. | 8 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefits of provisional patent application Ser. No. 61/233,765 filed on Aug. 13, 2009, the entire contents of which is incorporated herein by reference. This application also claims the benefits of provisional patent application Ser. No. 61/243,079 filed on Sep. 16, 2009, the entire contents of which is incorporated herein by reference.
STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT
[0002] Not Applicable
BACKGROUND
[0003] The present invention relates generally to a system and method for optimizing riserless drilling casing seats used in offshore deepwater drilling from a floating platform. More particularly, the present invention uses a system and method for determining the optimal placement of the initial casing seats by using, among other criteria, the relationship between the pore pressures and fracture pressures to determine a depth that will optimize placement of riserless casing seats to achieve deeper well depths, minimize casing diameter reduction, decrease the likelihood of well failure and more efficient use of well construction materials.
[0004] The continuing demand for crude oil and natural gas combined with the limited number of near shore fields and has provoked the exploration and production of offshore crude oil and natural gas to increasing water depths. Increasing water depths have required the use of floating platforms that support a drilling rig and drilling equipment. Advances in floating platform technology has increased the weight loads that the platforms can safely utilize and as such, drilling strings, generally formed of jointed steel pipe, can reach greater depths.
[0005] In conventional floating platform deepwater drilling, riserless drilling is used. In riserless drilling there is no return conduit provided back to the platform surface, as is done in many shallow water drilling operations. In conventional riserless drilling, the drilling cuttings and other by-products are discharged to the seafloor and are typically swept away by currents. In drilling the riserless portion of the well, the first casing, typically of a length of about 250 to 350 feet, is lowered from the platform and jetted into place into the seafloor. This first string of casing is commonly referred to as the structural or conductor string. A general description of riserless drilling is provided in U.S. Pat. No. 7,150,324, the entire substance of which is incorporated herein by reference.
[0006] The current approach of “jetting” in the first string of casing, usually 250 to 350 ft below the mud line, results in a casing seat being placed too shallow thereby not providing enough leak-off tolerance for the drilling of the next hole section. This is due to the very soft formations which have little strength or competency for fracture resistance and leak-off. The current philosophy of the first casing seat placement is to provide structural support for the weight of the subsequent casing strings and the bending moment of the riser, which will be eventually attached. The general intended purpose of the structural string is limited to supporting the weight of subsequent casing strings and wellhead, and the resistance of bending moment of the riser loading. Despite this perception, in reality, the structural string's ability to support much of an axial load is limited and thus can become a structural failure hazard if there is not enough soil bearing strength for the landing of the subsequent strength of casing and wellhead. The conventional approach adds little to the value of the well design, since this casing setting depth does not supply sufficient axial loading resistance for structural support of subsequent deeper casing strings nor does it supply sufficient bending load or sufficient rising bending moment. Also, there is no value related to the growth of the fracture gradient in the first string and that negatively impacts the overall well design by wasting casing diameters. Because the conventional placement of the casing well above every anticipated drilling hazard, such placement negatively impacts the casing diameters and hole sizes for well depths that routinely exceed 30,000 ft in measured depth. In this regard, the structural casing placement has been conventionally completed without regard to its optimal placement depth, but rather as a mere first step in the process of riserless drilling.
[0007] As is understood in the art, deepwater oil drilling is an expensive and time intensive venture. Daily operating costs often approach $1,000,000.00 requiring 100 days or more to drill before achieving the well objectives. Therefore, it is critical to deepwater field development to reduce well costs and to improve the attainment of these well objectives. The complex deepwater drilling environments have pushed well design to its limits and while many of the aspects of deepwater drilling and well design are being optimized, the optimal placement of the first and subsequent casing seats have been overlooked. As such there is a need in the art for a system and method that takes advantage of the increased maximum loads from floating platforms and provides for the determination of the optimal depth of placement of the early depth casing seats and placement of those seats to maximize drilling depths, drilling time and costs of operation.
BRIEF SUMMARY
[0008] The present invention provides a system and method of optimizing casing seats for riserless deepwater oil and natural gas drilling of hole sections and corresponding stings of casings by providing a design system and methodology for optimum casing set placement. The well design system and method of the present invention effectively takes advantage of the shallow and rapid growth of the fracture gradient in the subsea environment to optimize casing seats and shallow hazard mitigation and therefore improves leak-off tolerances for each successive casing string which allows for fewer and larger diameter casing strings than in a conventional deepwater well. In operation, the method and system of the present invention employs the use of common oilfield tubular diameters to attain well true vertical depth, allows for more conventional hole diameters for mechanical and geological side-tracks, a final well diameter that is optimized for field development flow rates, limiting failure hazards, allowing for the attainment of well objectives and well field development economic objectives.
[0009] The system and method of optimizing casing seats for riserless deepwater drilling of the present invention applies to the riserless drilled sections of deepwater drilling environments, primarily above salt formations (supra salt) but can also apply to any deepwater riserless environment requiring improvements in casing seat placement, whether salt is present or not. In operation, the casing seat placements are calculated and determined to meet pore pressure and fracture gradient leak-off requirements, also providing an acceptable leak-off for all subsequent casing string drilling operations, as well as meeting structural requirements beginning with the first casing string. In order to successfully determine and design such a composite or telescoping string of casings for minimizing the number of casing strings and diameters of casing strings for the improved well design, the first casing string must provide for, and take advantage of, the natural progressive growth of the fracture gradient. Therefore, the design of the first string provides both structural integrity as well as leak-off integrity for the drilling and subsequent placing of the subsequent casing strings. One of the differences of the present invention as compared to the prior art conventional riserless casing string placement is that data is used to calculate the optimal placement of the first casing string, normally referred to as the “structural” string. The structural string, with implementation of the present invention, becomes a dual purpose casing string: the string is not only structural, but also provides leak off tolerance by way of honoring the early growth of the natural fracture gradient of the subsea environment. The suggestion that casing drilling will assist in mitigating shallow drilling hazards to allow casing seats to be placed as prescribed by this present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] These and other features and advantages of the various embodiments disclosed herein will be better understood with respect to the following description and drawings, in which like numbers refer to like parts throughout, wherein:
[0011] FIG. 1 graphically illustrates the comparison of typical conventional riserless casing well design against the well design of the present invention showing the reduction of equivalent circulating density when there is a reduction of one casing string in the well design;
[0012] FIG. 2 graphically illustrates the fracture gradient and pore pressure of a prior art deepwater supra salt casing seat well design and the non-optimized placement of the casing strings;
[0013] FIG. 3 graphically illustrates the fracture gradient and pore pressure of the improved casing seat of the present invention, and the optimal positioning of the casing seats;
[0014] FIG. 4 graphically illustrates the fracture gradient and pore pressure of both the prior art conventional string placement and the placement of the present invention (a combination of FIG. 2 and FIG. 3 ).
[0015] FIG. 4A graphically illustrates the fracture gradient and pore pressure of both the prior art conventional string placement and the placement of the present invention, based upon a different example, with pictorial representations of the casing seats;
[0016] FIG. 5 graphically illustrates the step in the method of the present invention for developing the fracture gradient curve;
[0017] FIG. 6 graphically illustrates the step in the method of the present invention for developing the pore pressure plot;
[0018] FIG. 7 graphically illustrates the step in the method of the present invention for identifying the optimal placement of the initial casing string;
[0019] FIG. 8 graphically illustrates the step in the method of the present invention for identifying the optimal placement of subsequent deeper casing strings;
[0020] FIG. 9A is a flowchart of a portion of the steps of the method of the present invention;
[0021] FIG. 9B is a flowchart of a portion of the steps of the method of the present invention;
[0022] FIG. 9C is a flowchart of a portion of the steps of the method of the present invention; and
[0023] FIG. 9D is a flowchart of a portion of the steps of the method of the present invention;
DETAILED DESCRIPTION
[0024] The description herein is given by way of example, and not limitation. Given the disclosure herein, one skilled in the art could devise variations that are within the scope and spirit of the invention disclosed herein, including various ways of calculating optimal depth data or casing seat placement. Further, the various features of the embodiments disclosed herein can be used alone, or in varying combinations with each other and are not intended to be limited to the specific combination described herein. Thus, the scope of the claims is not to be limited by the illustrated embodiments.
[0025] The present invention relates to a system and method for the optimum placement of drilling casing strings in deepwater drilling environments. The present invention uses a computer for processing and calculating the data necessary to optimize the placement of the casing strings as described herein. In operation, the code used to execute the data collection and computation may be preferably placed on a computer server which is accessible by one or more peripheral devices. The server may include one or more computer memories for storing accumulated data, and one or more processers for completing the calculations necessary to perform the steps of the method of the present invention. Furthermore, the computer code of the method of the invention may be stored on a storage medium readable by a computer, wherein the storage medium tangibly embodies one or more of the computer programs set of instructions executable by the computer to perform the method of optimal placement of the support casing in a subsea drilling environment. The method of the present invention may also include the actual production of the executable computer program code, and providing the code program to be deployed and executed on the computer system to thereafter complete the method for determining the optimal placement of the casing strings as described herein.
[0026] Referring particularly to FIGS. 2 , 3 , and 4 the method and system of the present invention improves upon the conventional approach of “jetting” the first string of casing into the subsea surface usually 250 to 350 feet below the mud line. In the prior art, because the casing seat is placed in an undesirable shallow position, such placement does not supply enough “leak-off” tolerance for the drilling in the next hole section due to typically soft formations encountered at shallow depths where there is little strength or competency for facture resistance. “Leak-off” is typically understood as the amount of pressure, expressed in pound per square inch (or similar units such as metrics) per true vertical foot of well depth (psi/foot) that is exerted by a column of drilling fluid on the formation being drilled where that fluid will continue to enter the formation or “leak-off”. The leak-off pressure is the maximum pressure of equivalent circulating mud density that may be applied to the well during the drilling operation. The “equivalent circulating density” is generally understood as the effective mud density expressed in pounds per square inch (or similar units such as metrics) per true vertical foot of well depth (psi/foot) exhibited by a circulating fluid at a circulating rate in gallons per minute (or similar units such as metrics) against the formation that takes into account the pressure drop in the annulus above the point of circulation due to friction and hydrostatic pressure.
[0027] In the prior art placement of casing strings, the first casing string, which may be commonly referred to as the structural or conductor string is typically designed for the limited purpose of supporting the weight of the subsequent casing strings and well head and the resistance of bending moment of the riser loading. In practice, however, the conductor string in the prior art may have limited ability to support such an axial load and can thus become a structural failure hazard if there is not enough soil bearing strength for the landing of the subsequent strength of casing and well head. As such, there is no value related to the growth of the fracture gradient in the first casing “structural” string in current well designs and this negatively impacts the overall well design by “wasting” casing diameters. For example, as graphically demonstrated in FIG. 4A , casing strings are placed in the well with each section of casing telescoping from the first large diameter conductor string to smaller diameter casing strings as the depth increases. In this regard, by placing the first casing string at a shallow depth, a diameter is wasted as the next placement is close to the mud line, but of lesser diameter. Therefore, in the prior art as graphically demonstrated in FIG. 2 such additional casing strings above each anticipated drilling hazard further negatively impact the casing diameters and hole sizes available for well depth that routinely exceed 30,000 feet measured depth.
[0028] Referring particularly to FIG. 2 , there is graphical depiction showing the prior art deepwater supra salt casing seats. The fracture gradient and pore pressure supra salt are plotted graphically in FIG. 2 . The facture gradient is the amount of pressure, expressed in pound per square inch (or similar units such as metrics) per true vertical foot of well depth (psi/foot) that is required to induce fractures in a rock at a given true vertical depth. The pore pressure is the amount of pressure or stress expressed in pounds per square inch (or similar units such as metrics) for true vertical foot of well depth (psi/foot) transmitted through the interstitial fluid of a soil or rock mass. Fracture gradient curve 20 is shown along with the pore pressure curve 22 . Riserless drilling methodology uses a mixture of seawater and drilling mud with the primary drilling fluid pumped down through a drill pipe. The drilling fluid cleans and cools the drill bit and lifts cuttings out of the hole as the hole is being drilled. Since there is not a riser conduit to the drilling rig, there are no drill cuttings to return to the rig, but rather the cuttings in the drilling fluid are returned directly to the seafloor where they may be dissolved or otherwise swept away by sea current.
[0029] FIG. 2 represents the prior art of placement strings in riserless drilling with facture gradient curve 20 and pore pressure curve 22 charted is a specific example of what may be encountered with a particular example well design and associated geological conditions. In particular, the representation of FIG. 2 is exemplary, and fracture gradient curve 20 and the pore pressure 22 curve may change with different well designs, locations, different depths or geological conditions. Furthermore, in specific situations, shallow water hazards 24 may be predicted for a particular well location. Furthermore, hydrocarbon features 26 may also be predicted. In the particular example of FIG. 2 , the top of salt (“TOS”) 28 is identified geologically as being situated at 6,700 ft. Furthermore, the mud line 30 is located at approximately at 3,500 ft where the first string or conductor string 32 is positioned. In the prior art placement of the conductor string 32 , the string is placed at the mud line at a jetted depth without regard to the optimal placement. Typically the riserless casing seat placements of the conductor string 32 is based upon the anticipation of shallow drilling hazards 24 with a belief that a casing seat 32 and subsequent casing seat 34 are placed above the drilling hazard 24 to aid in the ability to drill through the hazard 24 . This low depth placement provides undesirable leak-off pressures. In this regard, the first casing string 32 which is typically is “jetted” to an arbitrary penetration depth of about 250 to 350 feet below the sea floor. Such placement is not optimal to the well design since the casing settings 32 and 34 do not supply sufficient axial loading resistance for structural support of such good casing strings nor does it provide bending load for the riser bending moment. Deeper casing strings 36 and 38 are placed at calculated depths taking into account drilling hazards, and the placement of the deeper strings is not optimal due to the less than optimal placement of strings 32 and 34 .
[0030] Referring particularly to FIG. 3 , there is shown graphical representation of the employed method for the optimum placement of the riserless casing strings in deepwater drilling environments. The present invention improves upon the prior art placement of casing strings by taking advantage of the early and progressive growth of this subsurface fracture gradient immediately below the mud line. The present invention provides safe “leak-off” for the drilling of subsequent holes in casing installation, mitigates shallow hazards, avoids “wasting” casing diameters in riserless hole sections and optimizes the sizes and number of strings of casing for the entire well. For example, as shown in FIG. 3 , a fracture gradient curve 40 is shown along with the pore pressure supra salt curve 42 . The depth and geological conditions are identical in the proposed well of FIG. 3 as it is the proposed well of FIG. 2 . For example, top of salt 44 is located at 6,700 feet. FIG. 3 demonstrates the optimal setting of the casing seats as the function of the fracture gradient. For example, the fracture gradient at the mud line 46 and is plotted in the y axis 48 until it meets with the pore pressure curve 42 . The plot line 48 that meets the pore pressure curve 42 at a point which designates the optimal placement of string casing one 50 . Likewise, in determining the second casing seats, the fracture gradient is extrapolated at line 52 along the x-axis to the fracture gradient curve 40 to the leak-off point 54 . The leak-off point 54 is then plotted along the y-axis 56 until it meets with the pore pressure curve 42 at point where the second string 58 is placed. Again, by extrapolating along the x-axis by line 60 to the point on the fracture gradient curve 40 a leak-off point 62 is determined. Using this methodology, each of the optimal points for placement of the casing strings is identified.
[0031] The system and method of the present invention provides for the use of common oil field tubular diameters to obtain true well vertical depth. This allows for more conventional hole diameters for mechanical and geological side tracks that may be encountered in a lower casing intervals. The well diameter is generally larger than the current art providing for optimal field development flow rates, for the obtainment of well objectives and for the field development economics. Geological “side tracks” involves the drilling operation of creating additional hole intervals between two planned intervals. In typical drilling operations, the objective is to drill in a hole section of a diameter so that the next planned interval can be maintained at the planned diameters. Sidetracks can occur due to mechanical difficulties in the well such as a stuck pipe or can occur to intersect secondary geological targets not possible without the side track operation. The optimal placement of the casing strings also creates a larger annulus than is achieved in the prior art design. Furthermore, the optimal positioning of the placement in the riserless casing can additionally mitigate the anticipated shallow drilling hazard.
[0032] Referring particularly to FIG. 1 , there is shown a comparison of the equivalent circulating density (“ECD”) plotted for both the prior art well design with that of the ECD plot of the present invention where the string casing is placed at optimal depth. The prior art ECD is plotted at curve 64 and the improved ECD of the design of a well produced in accordance with the method of the present invention, is shown at curve 66 . As is shown the ECD in the design of the present invention can improve as much as 0.1 pounds per gallon (ppg) near the end of the well, with only a reduction of one casing string from the prior art. Additional ECD reductions would be attained if even fewer casing strings were used. However this is a function of the specific pore pressure and fracture gradient environment for each specific deepwater well location. Even this small difference can mean the ability to being able to drill without losses and with less risk taking a formation influx into the well bore.
[0033] Referring particularly to FIGS. 4 , there is shown a comparison of FIGS. 2 and 3 . FIG. 4 is a graphical representation showing the comparison between the prior art well design of FIG. 2 and the present invention design of FIG. 3 .
[0034] FIG. 4A depicts the use of the method of the present invention for optimal placement of casing seats in comparison with another example of the prior art method in relation to a 64 a floating drilling platform. The drilling platform 64 is used in combination with casing seats 66 that have been deployed in accordance with the prior art method. As noted in the example, a water depth of 3,500 feet is provided and a first casing seat 68 is placed at a shallow depth. Again, the placement casing seats 64 is not driven by the optimal placement but rather at a first step in moving forward with the placement of second and subsequent casing seats. For example, a second casing seat is provided 70 which is placed in reverse telescoping fashion within the casing seat 68 . Again, casing seats 72 , 74 and 76 are each placed in the well at increasing depths without regard to optimal placement. Generally, the placement may be driven by placing casing seats at points just above a drilling hazard based on the belief that such placement facilitates the ability to drill through the drilling hazard. As shown in the example of FIG. 4A , from drilling platform 64 five casing seats were utilized to reach a depth of 6,500 feet. The fifth casing seat 76 has a narrow diameter, which with the diameter reducing telescopic effect on subsequent casing diameters, will limit well fluid production ability to less than optimum, and, as well may limit the ultimate depth at which the well may reach.
[0035] On the other hand, the improved casing seat design 78 is shown in association with drilling platform 80 . Utilizing the methodology previously described with respect to FIG. 3 the casing seat depth 82 is determined for casing seat 84 . Likewise, depth is determined 86 for casing seat 88 . Finally the casing seat depth 90 is determined for the third casing seat 92 .
[0036] As is apparent from the comparison of the prior art casing seat 66 with the improved casing seat 78 , the improved casing seat 78 achieves a depth of approximately 6,500 feet while employing only three casing strings as appose to five casing strings for casing seat 66 . In this regard, casing diameter is conserved rather than “wasted” as compared with the prior art casing seat 66 .
[0037] A method of the present invention provides the design steps to enable the well to be drilled deeper and the setting depths for the riserless string of casings to where the formations have a higher degree of competency for fracture resistance and therefore higher leak-off pressure. This allows for the first string of the casing not only to provide the structural integrity necessary to support axial loading of the string of casing but also takes advantage of the growth of the fracture gradient below the mud line thereby affecting leak-off tolerance to continue drilling with the subsequent drilling and inclination of the second string of casing.
[0038] Referring particularly to FIGS. 5-8 and FIGS. 9A-9D the method of the present invention is described. In particular, FIGS. 9A through 9D comprise a composite flow-chart of the steps of the present invention. By competing the steps of the method of the present inventions, the method of placing subsea well casings is improved over the approach of the prior art as the method aids in identifying the optimal placement of the casing seats. Although the invention applies to riserless drill sections of deepwater drilling environments, primarily above salt formations (i.e. supra salt) it should be recognized that the present invention can apply to any deepwater riserless environment requiring improvements in casing seat placements, whether salt is present or not present. The method of the present invention operates based upon the premise that casing seat placements must all meet, not only the pore pressure and fracture and gradient leak-off requirements, specifically providing an acceptable leak-off for all subsequent casing string drilling operations, but also must meet structural requirements beginning with the first casing strings. In order to successfully design such a composite or telescopic string of casing and thereby minimizing the number of casing strings to obtain an improved well design, the invention contemplates that the first casing string must provide for and take advantage of the natural progressive growth of the fracture gradient as depicted in FIG. 5 . Therefore, the design of the first conductor string provides both structural integrity as well as the leak-off integrity of the drilling in subsequent placement of the next casing. Thus the optimal placement of the first casing string is a critical design difference than the prior art placement of the casing strings of simply jetting in the first casing string at a convenient or arbitrary depth.
[0039] The optimized placement of the riserless casing seat in the shallow subsea formations mitigate shallow drilling hazards with the casing true vertical depths being based upon the shallow rapidly growing fracture strength, and reinforced by the smearing effect of casing drilling and improved ECD control of casing drilling. The drilling hazard mitigating aspect of casing drilling of the present invention may also result in achieving still deeper casing seats in those posed in FIGS. 3 and 4A .
[0040] Referring to FIG. 9A , there is shown the first three steps in the process and method of the present invention. In Step 1 ( 51 ) the fracture gradient is obtained from direct inputs 100 . Furthermore, pore pressure is additionally obtained from direct inputs 104 . The data inputs 100 and 104 may be input manually through a peripheral device into a computer and the data may be stored in memory. It is additionally contemplated by the present invention that such inputs 104 and 100 may be undersea sensors or other input devices. In Step 1 , 102 , the fracture gradient curve is developed. In the first step of developing fracture gradient, the data from 100 is used in determining the estimated fracture gradient for a proposed deepwater well from below the mud line to the total anticipated true vertical depth of the well. The development of the fracture gradient curve is exemplified in FIG. 5 .
[0041] In Step 2 of the method of the present invention pore pressure is analyzed and a pore pressure curve is developed 106 from data in element 104 . In developing the pore pressure curve the estimated pore pressure for a proposed deepwater well from below the mud line to the total anticipated true vertical depth of the well is exemplified in FIG. 6 (shown with the gradient curve from FIG. 5 ).
[0042] In the third step, the data is integrated to develop a pore pressure/fracture gradient versus total vertical depth graphic. The graphic which includes both the fracture gradient curve and the pore pressure curve is shown in FIG. 6 . Using the data developed in the first and second steps, the data is integrated in the third step 108 to develop the total anticipated true vertical depth of the well, and extend the pore pressure/fracture gradient versus true vertical depth curve to interpolate and depict optimum setting true vertical depths for all casing strings. In 110 , the graph may be adjusted to the input of the observable data which may have not been obtained through the data inputs of 100 and 104 . In 112 , the data developed inputs 104 and 100 as well as the observable data from 110 a graph is computed in 112 .
[0043] Referring particularly to FIG. 9B , Step 4 , 114 is shown as inputting the identification of shallow hazards. Then the input data may be stored in a computer memory. Step 4 , 114 identifies the possible presence and location of shallow drilling hazards. The method may thereafter assess the magnitude and risk of the shallow hazard data. The shallow hazard data is overlaid onto the pore pressure/fracture gradient plot 116 and a Pore Pressure plot is developed and finalized in 117 . In Step 5 118 from the graph information a determination is made of the deepest true vertical depth at which the pore pressure is not anticipated to exceed the pressure exerted by the salt water only. A more detailed discussion with respect to FIG. 3 indicates the calculation and extrapolation that is involved in determining this position. In Step 6 A the location and placement of the conductor casing is placed on the graph 120 . Step 6 A determines the optimum setting true vertical depth of riserless string one by interpolating a subsea true vertical water depth where the pore pressure begins to exceed the normal gradient of salt water. The corresponding feature gradient true vertical depth becomes the setting true vertical depth for casing string one. The salt water gradient is the amount of pressure, expressed in pounds per square inch (or similar units such as metrics) per true vertical foot of water depth (psi/foot) exerted by a column of salt water.
[0044] The requirements for string one therefore ensures that the true vertical depth is deep enough to facilitate an acceptable “leak-off” for the drilling of string two, but, must also meet the engineered design requirements for landing support of string two. It is noteworthy that the hole section drilled for the first casing string placement is within a pressure environment governed only by the salt water gradient of the pressure envelope. Since this true vertical depth environment is represented only by the salt water gradient and the formations are soft, transmissible and unconsolidated sediments incapable of trapping oil and gas deposits, then there is no potential geological trap for higher pressure free hydrocarbon hazards in the depositional environments. The added stress of overburdens gradient does not affect this pore pressure environment at this true vertical depth. Overburden is the amount of pressure or stress expressed in pounds per square inch (or similar units such as metrics) for true vertical foot of well depth below the ocean flow mud line (psi/foot) and imposed on a layer of soil or rock by the weight of the over lining material.
[0045] Hazards such as frozen methane, mud loses, and fresh water flows, are the only three possible shallow hazards that may be encountered since there is not a geological trap. Mitigating shallow hazards is a requirement for all drilling operations. Riserless dynamic kill density mud is commonly used for shallow drilling operation and the ability to employ mud density as achieved by dual gradient mud system equal to or slightly greater than the weight of salt water. Dynamic kill weight or dynamic kill density is the equivalent circulating density composite dual gradient mud density necessary to effect a mud balance to ensure the integrity to counteract any pore stress related pressure of the hole section being drilled. A dual mud gradient system represents the dual gradient mud weight of the riserless drilling system. The first component is the gradient of sea water from the rig floor to the sea bed or mud line, and the second component represents the column weight of the mud gradient in the wellbore being drilled. The combination of these two gradients represents the composite mud density of the circulating dual gradient mud system.
[0046] Methane Hydrate is a gas in frozen state and occurs in sediments in water depths greater than 300 m, and in temperatures less than 2 degree C. Its occurrence in the frozen state is governed by Boyle's Law and therefore predictable where these conditions occur. If the gas is in a frozen state it will not migrate unless in-situ temperatures and/or pressures are changed and therefore the gas remains static and therefore not a moveable dynamic drilling hazard. Care must be taken to avoid heating or disassociating or melting the gas, however, absent disassociation, this has no bearing on casing seat optimization for the first string of casing. The byproducts of disassociation are free natural gas and water either of which can become artificially induced drilling hazards.
[0047] The primary hazard then becomes fluid losses if the equivalent circulating density of mud weight exceeds the formation pressure. Fresh water flows are mitigated using dynamic kill weight mud. Casing drilling has a known improving ability to mitigate fluid loss and is a method of choice from mitigation on this shallow hazard.
[0048] There is only one other factor that can influence the ability to optimize the first casing string true vertical depth and that is the presence of a known shallow trap. In this case the optimum true vertical depth would be governed by the true vertical depth of the geological base of the trap. Depending on the deepwater basin this may have the net affect of shortening the first casing strings true vertical depth, but nonetheless achieve the objective of optimizing the first casing seat beyond the conventional jetting true vertical depth for first casing string.
[0049] In steps 6 B, element 122 the method of the present invention develops a temperature gradient to true value depth. Input is received from 124 which include the subsea temperature prediction to the true value depth of the well. In 122 this step determines if the temperature envelope (Boyle' s Law) allows for a frozen gas environment (Methane Hydrate).
[0050] Referring to FIGS. 9C and 9D , in element 126 a determination is made as to whether the first casing string placement is within the frozen Methane Hydrate range. If the answer is “no” the process includes element 128 that can re-compute the string one depth, if necessary. If the string one is within the frozen range 126 (“yes”) then the process diverts to element 130 where the interval depth of string one is re-evaluated. At that point, manual input may be solicited at 132 for the placement of the maximum depth interval for Methane Hydrate avoidance. In 134 Step 6 C string one may be adjusted for casing seat depth for Methane Hydrate or other potential hazards or other mitigation keeping the depth the same. The purpose of element 134 is to change the depth of the first casing string to accommodate a setting depth above the Methane Hydrate or other mitigant. Methane Hydrate occurs at depth and deep water environment according to temperature. If it is possible that the Methane Hydrate will occur, either the casing seat depth must be change to accommodate the depth by setting the casing to avoid the potential hazard, or some other mitigant applied such as controlling circulating temperature if possible to mitigate accordingly. Once the temperature has been taken into account in steps 6 A, 6 B and 6 C the process is continued for Step 7 in element 136 to determine the true value depth for string two and subsequent casing string by following the pore pressure/fracture gradient trends to the true value depth of the well. Therefore in process element 138 additional requirements are determined for additional riserless casing strings, if any, then continue casing seats designed depth in the same manner for all strings to true value depth. The process is continued to determine the optimal true vertical depth for the second casing string by following the pore pressure/fracture gradient trends to total true vertical depth of the well. Following this trend the process visualizes the optimum true vertical depth for second casing string as well as sub strings required to reach the true vertical depth. The process for the selection of the additional riserless casing strings in step 8 is shown in FIG. 8 .
[0051] Referring to FIG. 8 , it is important that the hole section for the second casing string have the ability to mitigate further shallow hazards such as trapped oil or gas. Overburden begins to become consolidated, less transmissible, and more capable of forming traps for free hydrocarbons. The ability of the mud density and equivalent circulating density must be able to offset in-situ pore pressure as well as the increasing stress of the overburdened. Losses can be mitigated with casing drilling, as discussed above, and the smaller annular volume improves the reaction time and decreases the possibility of channeling (smaller annulus), for increasing dynamic kill (ECD) weight required to offset these in-situ conditions. In Step 8 138 , the method evaluates the requirement for any additional riserless casing strings to be drilled prior to running the casing that will continue drilling the well in the conventional manner. Determine the optimum casing seat true vertical depth in the same manner as steps 5 - 7 . Additional alternate steps may be provided within the method of the present invention. For example, a structural analysis of riserless strings and loading 140 can be implemented in Step 9 . This requires a verification that all casing and casing connections have the required mechanical strength for the anticipated loads of installation and well service. Furthermore, industry well control software and regulations may require additional steps as discussed in Steps 10 and 11 . For example Step 10 includes the adjusting of all casing true seats depths by the difference derived for kick tolerance (well control) requirements, versus the visualized optimum true value depth for each string. This represents the safest true vertical depth at each hole section can be drilled to and warrants that leak-off tolerance will not be exceeded. The kick tolerance is the maximum kick volume of fluid that can be taken into the wellbore and circulated out without fracturing the formation at a weak point (shoe) thereby exceeding the leak-off, given a difference between the pore pressure and the equivalent circulating density, mud density in use.
[0052] Casing seats design true vertical depths, may also be adjusted for a pore pressure safely factor. That is, the user may have a policy or procedure in place to adjust the pore pressure estimates to a higher value to help ensure that the applied equivalent mud weight and circulating density does not exceed a safe tolerance that might risk wellbore stability for flow or well control events in the interval being drilled.
[0053] Likewise, Step 11 may be implemented to develop the optimum seat depth for all conventional strings below the riserless casing strings using the same pore pressure fracture gradient curves extended to total depths. The step applies the appropriate well tolerances and adjusts the casing seats design depths accordingly. Further Step 11 , element 150 may include the finalizing of the riserless casing design by conducting a complete engineering and structural analysis to ensure that all weights grades, and sizes of casing strings meet or exceeds the operator requirements for safe and successful completion of the well for further conventional drilling and casing installation. A final step 13 , element 150 may include drilling hazard mitigation by ensuring drilling risk assessments and mitigation plans have been vetted and are ready for implementation. | A system and method for optimal placement of a riserless casing in a subsea drilling environment having the steps of: receiving input of pore pressure data for a well site; receiving input of fracture gradient for said well site; receiving input of the anticipated true vertical depth of said well site; integrating pore pressure data, fracture gradient data with said true vertical depth values; computing a pore pressure and fracture gradient verses true vertical depth graph; determining the true vertical depth at which the pore pressure begins to exceed the normal gradient of salt water; and determining the placement of a conductor casing string by corresponding the gradient true vertical depth to the true vertical depth of where the pore pressure beings to exceed the normal gradient of salt water. The method improves upon conventional placement of the riserless casing by optimizing the placement to achieve larger diameters in the wellbore, increased well depth, and mitigation of shallow hazards. Furthermore, the method of the present invention transforms readily available data to calculate optimal placement of a structural casing string to serve a dual purpose by providing not only structural integrity for the wellbore, but also ensuring leak-off integrity by taking advantage of the early growth of the fracture gradient of the natural subsea environment. Also, the suggestion that casing drilling will assist in mitigating shallow drilling hazards to allow casing seats to be placed as prescribed by this present invention. The method of the present invention may be implemented by a computer based apparatus or implemented using executable computer code on a computer based system. | 4 |
FIELD OF THE INVENTION
[0001] This invention concerns a synergistic herbicidal composition containing (a) fluroxypyr and (b) quinclorac for controlling weeds in crops, especially rice, cereal and grain crops, pastures, rangelands, industrial vegetation management (IVM) and turf. This composition provides improved post-emergence herbicidal weed control.
BACKGROUND OF THE INVENTION
[0002] The protection of crops from weeds and other vegetation which inhibit crop growth is a constantly recurring problem in agriculture. To help combat this problem, researchers in the field of synthetic chemistry have produced an extensive variety of chemicals and chemical formulations effective in the control of such unwanted growth. Chemical herbicides of many types have been disclosed in the literature and a large number are in commercial use.
[0003] In some cases, herbicidal active ingredients have been shown to be more effective in combination than when applied individually and this is referred to as “synergism.” As described in the Herbicide Handbook of the Weed Science Society of America, Eighth Edition, 2002, p. 462 “‘synergism’ [is] an interaction of two or more factors such that the effect when combined is greater than the predicted effect based on the response to each factor applied separately.” The present invention is based on the discovery that fluroxypyr and quinclorac, already known individually for their herbicidal efficacy, display a synergistic effect when applied in combination.
SUMMARY OF THE INVENTION
[0004] The present invention concerns a synergistic herbicidal mixture comprising an herbicidally effective amount of (a) fluroxypyr and (b) quinclorac. The composition may also contain an agriculturally acceptable adjuvant and/or carrier.
[0005] The present invention also concerns herbicidal compositions for and methods of controlling the growth of undesirable vegetation, particularly in monocot crops including rice, wheat, barley, oats, rye, sorghum, corn, maize, pastures, grasslands, rangelands, fallowland, turf, IVM and aquatics and the use of these synergistic compositions.
[0006] The species spectrum of quinclorac is broad and highly complementary with that of fluroxypyr. For example, it has been surprisingly found that a combination of quinclorac and fluroxypyr exhibits a synergistic action in the control of barnyardgrass ( Echinochloa crusgalli ; ECHCG), Chinese sprangletop ( Leptochloa chinensis ; LEFCH) and broadleaf signalgrass ( Brachiaria platyphylla ; BRAPP) at application rates equal to or lower than the rates of the individual compounds.
DETAILED DESCRIPTION OF THE INVENTION
[0007] Fluroxypyr is the common name for [(4-amino-3,5-dichloro-6-fluoro-2-pyridinyl) oxy]acetic acid. Its herbicidal activity is described in The Pesticide Manual , Fifteenth Edition, 2009. Fluroxypyr controls a wide range of economically important broadleaf weeds. It can be used as the acid itself or as an agriculturally acceptable salt or ester. Use as an ester is preferred, with the meptyl ester being most preferred.
[0008] Quinclorac is the common name for 3,7-dichloro-8-quinolinecarboxylic acid. Its herbicidal activity is described in The Pesticide Manual , Fifteenth Edition, 2009. Quinclorac controls Echinochloa spp., Brachiaria spp., Digitaria spp. and many broadleaf weeds in rice and turf.
[0009] The term herbicide is used herein to mean an active ingredient that kills, controls or otherwise adversely modifies the growth of plants. An herbicidally effective or vegetation controlling amount is an amount of active ingredient which causes an adversely modifying effect and includes deviations from natural development, killing, regulation, desiccation, retardation, and the like. The terms plants and vegetation include germinant seeds, emerging seedlings, plants emerging from vegetative propagules, and established vegetation.
[0010] Herbicidal activity is exhibited by the compounds of the synergistic mixture when they are applied directly to the plant or to the locus of the plant at any stage of growth or before planting or emergence. The effect observed depends upon the plant species to be controlled, the stage of growth of the plant, the application parameters of dilution and spray drop size, the particle size of solid components, the environmental conditions at the time of use, the specific compound employed, the specific adjuvants and carriers employed, the soil type, and the like, as well as the amount of chemical applied. These and other factors can be adjusted as is known in the art to promote non-selective or selective herbicidal action. Generally, it is preferred to apply the composition of the present invention postemergence to relatively immature undesirable vegetation to achieve the maximum control of weeds.
[0011] In the composition of this invention, the weight ratio of fluroxypyr as measured in grams acid equivalent per hectare (g ae/ha) to quinclorac as measured in grams active ingredient per hectare (g ai/ha) at which the herbicidal effect is synergistic lies within the range of between about 1:11 and 22:1.
[0012] The rate at which the synergistic composition is applied will depend upon the particular type of weed to be controlled, the degree of control required, and the timing and method of application. Quinclorac is applied at a rate between about 26 g ai/ha and about 560 g ai/ha, and fluroxypyr is applied at a rate between about 50 g ae/ha and about 560 g ae/ha.
[0013] The components of the synergistic mixture of the present invention can be applied either separately or as part of a multipart herbicidal system, which can be provided as a premix or a tank mix.
[0014] The synergistic mixture of the present invention can be applied in conjunction with one or more other herbicides to control a wider variety of undesirable vegetation. When used in conjunction with other herbicides, the composition can be formulated with the other herbicide or herbicides, tank mixed with the other herbicide or herbicides or applied sequentially with the other herbicide or herbicides. Some of the herbicides that can be employed in conjunction with the synergistic composition of the present invention include: 2,4-D, acetochlor, acifluorfen, aclonifen, AE0172747, alachlor, amidosulfuron, aminotriazole, ammonium thiocyanate, anilifos, atrazine, AVH 301, azimsulfuron, benfuresate, bensulfuron-methyl, bentazone, benthiocarb, benzobicyclon, bifenox, bispyribac-sodium, bromacil, bromoxynil, butachlor, butafenacil, butralin, cafenstrole, carbetamide, carfentrazone-ethyl, chlorflurenol, chlorimuron, chlorpropham, cinosulfuron, clethodim, clomazone, clopyralid, cloransulam-methyl, cyclosulfamuron, cycloxydim, cyhalofop-butyl, dicamba, dichlobenil, dichlorprop-P, diclosulam, diflufenican, diflufenzopyr, dimethenamid, dimethenamid-p, diquat, dithiopyr, diuron, EK2612, EPTC, esprocarb, ET-751, ethoxysulfuron, ethbenzanid, F7967, fenoxaprop, fenoxaprop-ethyl, fenoxaprop-ethyl+isoxadifen-ethyl, fentrazamide, flazasulfuron, florasulam, fluazifop, fluazifop-P-butyl, flucetosulfuron (LGC-42153), flufenacet, flufenpyr-ethyl, flumetsulam, flumiclorac-pentyl, flumioxazin, fluometuron, flupyrsulfuron, fomesafen, foramsulfuron, fumiclorac, glufosinate, glufosinate-ammonium, glyphosate, haloxyfop-methyl, haloxyfop-R, halosulfuron-methyl, imazamethabenz, imazamox, imazapic, imazapyr, imazaquin, imazethapyr, imazosulfuron, indanofan, indaziflam, iodosulfuron, ioxynil, ipfencarbazone (HOK-201), IR 5790, isoproturon, isoxaben, isoxaflutole, KUH-071, lactofen, linuron, MCPA, MCPA ester & amine, mecoprop-P, mefenacet, mesosulfuron, mesotrione, metamifop, metazosulfuron (NC-620), metolachlor, metosulam, metribuzin, metsulfuron, molinate, MSMA, napropamide, nicosulfuron, norflurazon, OK-9701, orthosulfamuron, oryzalin, oxadiargyl, oxadiazon, oxazichlomefone, oxyfluorfen, paraquat, pendimethalin, penoxsulam, pentoxazone, pethoxamid, picloram, picolinafen, piperophos, pretilachlor, primisulfuron, profoxydim, propachlor, propanil, propyrisulfuron (TH-547), propyzamide, prosulfocarb, prosulfuron, pyraclonil, pyrazogyl, pyrazosulfuron, pyribenzoxim (LGC-40863), pyriftalid, pyriminobac-methyl, pyrimisulfan (KUH-021), pyroxsulam, pyroxasulfone (KIH-485), quizalofop-ethyl-D, S-3252, sethoxydim, simazine, SL-0401, SL- 0402, S-metolachlor, sulcotrione, sulfentrazone, sulfosate, tebuthiuron, tefuryltrione (AVH-301), terbacil, thiazopyr, thiobencarb, triclopyr, trifluralin and tritosulfuron.
[0015] The synergistic composition of the present invention can, further, be used in conjunction with glyphosate, glufosinate, dicamba, imidazolinones, sulfonylureas, or 2,4-D on glyphosate-tolerant, glufosinate-tolerant, dicamba-tolerant, imidazolinone-tolerant, sulfonylurea-tolerant and 2,4-D-tolerant crops. It is generally preferred to use the synergistic composition of the present invention in combination with herbicides that are selective for the crop being treated and which complement the spectrum of weeds controlled by these compounds at the application rate employed. It is further generally preferred to apply the synergistic composition of the present invention and other complementary herbicides at the same time, either as a combination formulation or as a tank mix.
[0016] The synergistic composition of the present invention can generally be employed in combination with known herbicide safeners, such as benoxacor, benthiocarb, brassinolide, cloquintocet (mexyl), cyometrinil, daimuron, dichlormid, dicyclonon, dimepiperate, disulfoton, fenchlorazole-ethyl, fenclorim, flurazole, fluxofenim, furilazole, harpin proteins, isoxadifen-ethyl, mefenpyr-diethyl, MG 191, MON 4660, naphthalic anhydride (NA), oxabetrinil, R29148 and N-phenyl-sulfonylbenzoic acid amides, to enhance their selectivity. Cloquintocet (mexyl) is a particularly preferred safener for the synergistic compositions of the present invention, specifically antagonizing any harmful effect of the synergistic compositions on rice and cereals.
[0017] In practice, it is preferable to use the synergistic composition of the present invention in mixtures containing an herbicidally effective amount of the herbicidal components along with at least one agriculturally acceptable adjuvant or carrier. Suitable adjuvants or carriers should not be phytotoxic to valuable crops, particularly at the concentrations employed in applying the compositions for selective weed control in the presence of crops, and should not react chemically with herbicidal components or other composition ingredients. Such mixtures can be designed for application directly to weeds or their locus or can be concentrates or formulations that are normally diluted with additional carriers and adjuvants before application. They can be solids, such as, for example, dusts, granules, water dispersible granules, or wettable powders, or liquids, such as, for example, emulsifiable concentrates, solutions, emulsions or suspensions.
[0018] Suitable agricultural adjuvants and carriers that are useful in preparing the herbicidal mixtures of the invention are well known to those skilled in the art. Some of these adjuvants include, but are not limited to, crop oil concentrate (mineral oil (85%)+emulsifiers (15%)); nonylphenol ethoxylate; benzylcocoalkyldimethyl quaternary ammonium salt; blend of petroleum hydrocarbon, alkyl esters, organic acid, and anionic surfactant; C 9 -C 11 alkylpolyglycoside; phosphated alcohol ethoxylate; natural primary alcohol (C 12 -C 16 ) ethoxylate; di-sec-butylphenol EO-PO block copolymer; polysiloxane-methyl cap; nonylphenol ethoxylate+urea ammonium nitrate; emulsified methylated seed oil; tridecyl alcohol (synthetic) ethoxylate (8EO); tallow amine ethoxylate (15 EO); PEG(400) dioleate-99.
[0019] Liquid carriers that can be employed include water, toluene, xylene, petroleum naphtha, crop oil, acetone, methyl ethyl ketone, cyclohexanone, trichloroethylene, perchloroethylene, ethyl acetate, amyl acetate, butyl acetate, propylene glycol monomethyl ether and diethylene glycol monomethyl ether, methyl alcohol, ethyl alcohol, isopropyl alcohol, amyl alcohol, ethylene glycol, propylene glycol, glycerine, N-methyl-2-pyrrolidinone, N,N-dimethyl alkylamides, dimethyl sulfoxide, liquid fertilizers and the like. Water is generally the carrier of choice for the dilution of concentrates.
[0020] Suitable solid carriers include talc, pyrophyllite clay, silica, attapulgus clay, kaolin clay, kieselguhr, chalk, diatomaceous earth, lime, calcium carbonate, bentonite clay, Fuller's earth, cottonseed hulls, wheat flour, soybean flour, pumice, wood flour, walnut shell flour, lignin, and the like.
[0021] It is usually desirable to incorporate one or more surface-active agents into the compositions of the present invention. Such surface-active agents are advantageously employed in both solid and liquid compositions, especially those designed to be diluted with carrier before application. The surface-active agents can be anionic, cationic or nonionic in character and can be employed as emulsifying agents, wetting agents, suspending agents, or for other purposes. Surfactants conventionally used in the art of formulation and which may also be used in the present formulations are described, inter alia, in “McCutcheon's Detergents and Emulsifiers Annual,” MC Publishing Corp., Ridgewood, N.J., 1998 and in “Encyclopedia of Surfactants,” Vol. I-III, Chemical Publishing Co., N.Y., 1980-81. Typical surface-active agents include salts of alkyl sulfates, such as diethanolammonium lauryl sulfate; alkylarylsulfonate salts, such as calcium dodecylbenzenesulfonate; alkylphenol-alkylene oxide addition products, such as nonylphenol-C 18 ethoxylate; alcohol-alkylene oxide addition products, such as tridecyl alcohol-C 16 ethoxylate; soaps, such as sodium stearate; alkylnaphthalene-sulfonate salts, such as sodium dibutyl-naphthalenesulfonate; dialkyl esters of sulfosuccinate salts, such as sodium di(2-ethylhexyl) sulfosuccinate; sorbitol esters, such as sorbitol oleate; quaternary amines, such as lauryl trimethylammonium chloride; polyethylene glycol esters of fatty acids, such as polyethylene glycol stearate; block copolymers of ethylene oxide and propylene oxide; salts of mono and dialkyl phosphate esters; vegetable oils such as soybean oil, rapeseed oil, olive oil, castor oil, sunflower seed oil, coconut oil, corn oil, cottonseed oil, linseed oil, palm oil, peanut oil, safflower oil, sesame oil, tung oil and the like; and esters of the above vegetable oils.
[0022] Other additives commonly used in agricultural compositions include compatibilizing agents, antifoam agents, sequestering agents, neutralizing agents and buffers, corrosion inhibitors, dyes, odorants, spreading agents, penetration aids, sticking agents, dispersing agents, thickening agents, freezing point depressants, antimicrobial agents, and the like. The compositions may also contain other compatible components, for example, other herbicides, plant growth regulants, fungicides, insecticides, and the like and can be formulated with liquid fertilizers or solid, particulate fertilizer carriers such as ammonium nitrate, urea and the like.
[0023] The concentration of the active ingredients in the synergistic composition of the present invention is generally from 0.001 to 98 percent by weight. Concentrations from 0.01 to 90 percent by weight are often employed. In compositions designed to be employed as concentrates, the active ingredients are generally present in a concentration from 1 to 98 weight percent, preferably 5 to 90 weight percent. Such compositions are typically diluted with an inert carrier, such as water, before application, or applied as a dry or liquid formulation directly into flooded rice fields. The diluted compositions usually applied to weeds or the locus of weeds generally contain 0.0001 to 10 weight percent active ingredient and preferably contain 0.001 to 5.0 weight percent.
[0024] The present compositions can be applied to weeds or their locus by the use of conventional ground or aerial dusters, sprayers, and granule applicators, by addition to irrigation or paddy water, and by other conventional means known to those skilled in the art.
[0025] The following examples illustrate the present invention.
[0026] Evaluation of Postemergence Herbicidal Activity of Mixtures in the Greenhouse
[0027] Seeds of the desired test plant species were planted in 80% mineral soil/20% grit planting mixture, which typically has a pH of 7.2 and an organic matter content of about 2.9 percent, in plastic pots with a surface area of 128 square centimeters (cm 2 ). The growing medium was steam sterilized. The plants were grown for 7-19 days in a greenhouse with an approximate 14-hour (h) photoperiod which was maintained at about 29° C. during the day and 26° C. during the night. Nutrients and water were added on a regular basis and supplemental lighting was provided with overhead metal halide 1000-Watt lamps as necessary. The plants were treated with postemergence foliar applications when they reached the third to fourth true leaf stage. All treatments were applied using a randomized complete block trial design, with 4 replications per treatment.
[0028] Evaluation of Postemergence Herbicidal Activity of Mixtures in the Greenhouse
[0029] Treatments consisted of the compounds as listed in Table 1 for each compound applied alone and in combination. Formulated amounts of quinclorac and fluroxypyr-meptyl ester were placed in 60 milliliter (mL) glass vials and dissolved in a volume of 60 mL of a water solution containing Agri-dex crop oil concentrate in a 1% volume per volume (v/v) ratio. Compound requirements are based upon a 12 mL application volume at a rate of 187 liters per hectare (L/ha). Spray solutions of the mixtures were prepared by adding the stock solutions to the appropriate amount of dilution solution to form 12 mL spray solution with active ingredients in single and two way combinations. Formulated compounds were applied to the plant material with an overhead Mandel track sprayer equipped with 8002E nozzles calibrated to deliver 187 L/ha at a spray height of 18 inches (43 centimeters (cm)) above average plant canopy.
[0030] The treated plants and control plants were placed in a greenhouse as described above and watered by sub-irrigation to prevent wash-off of the test compounds. Treatments were rated at 21 days after application (DAA) as compared to the untreated control plants. Visual weed control was scored on a scale of 0 to 100 percent where 0 corresponds to no injury and 100 corresponds to complete kill.
[0031] Table 1 demonstrates the herbicidal synergistic efficacy of quinclorac+fluroxypyr-meptyl tank mixes on weed control. All treatment results, both for the single product and mixtures, are an average of 4 replicates evaluated at 21 days after application, and the tank mix interactions are significant at the P>0.05 level.
[0032] Colby's equation was used to determine the herbicidal effects expected from the mixtures (Colby, S. R. Calculation of the synergistic and antagonistic response of herbicide combinations. Weeds 1967, 15, 20-22.).
[0033] The following equation was used to calculate the expected activity of mixtures containing two active ingredients, A and B:
[0000] Expected= A+B −( A×B/ 100)
[0034] A=observed efficacy of active ingredient A at the same concentration as used in the mixture.
[0035] B=observed efficacy of active ingredient B at the same concentration as used in the mixture.
[0036] The compounds tested, application rates employed, plant species tested, and results are given in Table 1. Rates of quinclorac are expressed in grams active ingredient/hectare (g ai/ha) and rates of fluroxypyr are expressed in grams acid equivalent per hectare (g ae/ha) in Table 1.
[0000]
TABLE 1
Synergistic Activity of Herbicidal Compositions of Quinclorac +
Fluroxypyr-meptyl on grass weeds barnyardgrass ( Echinochloa
crus - galli ), Chinese sprangletop ( Leptochloa chinensis ) and
broadleaf signalgrass ( Brachiaria platyphylla )
in the greenhouse at 21DAA.
Application Rate
Fluroxypyr-
% Control
Quinclorac
meptyl
ECHCG
BRAPP
LEFCH
(g ai/ha)
(g ae/ha)
Ob
Ex
Ob
Ex
Ob
Ex
26
0
5
—
—
—
5
—
0
50
0
—
—
—
6
—
26
50
30
5
—
—
20
10
26
0
—
—
—
—
—
—
0
100
—
—
—
—
—
—
26
100
—
—
—
—
—
26
0
5
—
5
—
5
—
0
200
6
—
5
—
41
—
26
200
35
11
30
9
86
44
53
0
6
—
—
—
10
—
0
50
0
—
—
—
6
—
53
50
46
6
—
—
43
15
53
0
6
—
—
—
—
—
0
100
11
—
—
—
—
—
53
100
27
15
—
—
—
—
53
0
6
—
6
—
—
—
0
200
6
—
5
—
—
—
53
200
65
11
48
10
—
—
110
0
31
—
5
—
15
—
0
50
0
—
5
—
6
—
110
50
85
31
25
10
35
20
110
0
31
—
5
—
15
—
0
100
11
—
1
—
50
—
110
100
81
38
51
6
62
57
110
0
31
—
5
—
15
—
0
200
6
—
5
—
42
—
110
200
91
35
31
9
56
50
220
0
65
—
—
—
11
—
0
50
0
—
—
—
50
—
220
50
90
65
—
—
60
55
220
0
65
—
26
—
—
0
100
11
—
1
—
—
—
220
100
86
68
41
27
—
—
220
0
65
—
26
—
—
—
0
200
6
—
5
—
—
—
220
200
75
67
49
30
—
—
BRAPP = Brachiaria platyphylla ; broadleaf signalgrass
ECHCG = Echinochloa crus - galli ; barnyardgrass
LEFCH = Leptochloa chinensis ; Chinese sprangletop
Ob = observed value (% control)
Ex = expected, calculated value using Colby Analysis (% control)
DAA = days after application
g ai/ha = grams active ingredient per hectare
g ae/ha = grams acid equivalent per hectare | An herbicidal synergistic mixture of fluroxypyr and quinclorac provides improved post-emergence weed control in rice, cereal and grain crops, pastures, rangelands, IVM and turf. | 0 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a packer for subterranean wells and particularly to a packer for accommodating various sizes of electrical cables in bypass relationship to the packer.
2. Summary of the Prior Art
In many subterranean wells it is desirable to mount an electric submersible pump in the portion of the well casing that is adjacent to a producing formation. Such pump may be conveniently suspended in the well by a packer, but a problem arises in supplying electrical power to the submersible pump by an electrical cable which does not pass through the bore of the tubing string which is connected to the top end of the packer and which is in fluid communication with the discharge end of the pump. Passing the cable through the bore of the tubing string obviously seriously reduces the fluid passage area for production fluid.
Accordingly, packers have been developed in the past wherein the electric cable for supplying energy to a submersible pump has traversed the body of a packer in eccentric relationship to a centrally mounted mandrel which communicates directly with the tubing string and the output of the submersible pump. A packer of this general type has been sold by BAKER PACKERS DIVISION of Houston, Tex. under the tradename of "BAKER MODEL "D" PACKOFF TUBING HANGER WITH CABLE BYPASS".
While this tool is completely functional, it suffers from the disadvantage that it will only efficiently accommodate one size of tubing string bore and one size of electrical cable. If it is desired to utilize a tubing string having a larger bore or larger cable than that for which the aforementioned packoff tubing hanger was designed, then it becomes necessary to redesign and manufacture a substantial number of components of the packoff tubing hanger in order to efficiently accommodate the revised sizes of either the bore of the tubing string or the diameter of the electrical cable.
SUMMARY OF THE INVENTION
It is, accordingly, an object of this invention to provide a retrievable packer for a subterranean well having a cable bypass which may be conveniently modified to accommodate different size bores of tubing string to which the packer is connected, and/or different size electrical cables, through revision of only two or three components of the packer assemblage, thus substantially reducing the cost of manufacture of any packer having non-standard tubing bore dimensions and/or non-standard electrical cable dimensions.
The objects of this invention are accomplished by the mounting of all of the active packing elements of the packer in a cylindrical shell configuration, and then effecting the connection between the tubing string above and below the packer by a mandrel sized to accommodate the internal bore dimensions of the tubing string to be used with the packer, which mandrel is supported within the packer assemblage by as few as two components. In similar fashion, the bypass for an electrical cable is provided by an eccentric hole provided in each of the two components requiring modification to accommodate the selected mandrel.
The major components of the cylindrical packer assemblage comprises a top sub having a cylindrical outer configuration but defining an eccentrically disposed passage having means at its upper end for connection to a tubing string and means at its lower end for connection to a mandrel which extends downwardly through the entire length of the packer. The top sub also defines an eccentric passage for receiving an electrical cable of the desired size. This passage is preferably connected at its upper end to a conventional cable penetration assembly by which a sealed relationship is achieved between the exterior of the electrical cable and the bore of the cable passage extending through the top sub.
The top sub is detachably secured to the upper end of an upper tubular body portion by a conventional shearable ring. Such upper body portion is of a diameter approaching that of the internal bore of the well conduit within which the cable bypass packer is to be mounted. The upper body portion is in turn connected to a body connector sub and this sub is connected to the top end of a lower tubular body portion. An upper mandrel support block may be mounted within the upper body portion and has longitudinal eccentric passages for respectively receiving the mandrel and the electrical cable.
The annular elastomeric packing elements commonly employed in packers and the annular slip and cone assemblage are mounted in surrounding concentric relationship respectively to the upper body portion and the lower tubular body portion.
The only other support provided for the mandrel and the electrical cable is provided by a generally cylindrical lower support block which is formed in two radially split pieces which are secured together in clamping relationship to the mandrel. The exterior of the cylindrical support block engages collet heads formed on the bottom end of the lower tubular body portion and maintains such collet heads in locking relationship with respect to an actuator assemblage for the lower slip cone. Thus, to accommodate a different size mandrel or a different size passage for the electrical conduit, it is only necessary to select a mandrel of the desired size and to redesign the top sub, the upper mandrel support block, if used, and the lower mandrel support block.
A cylinder sleeve is mounted in surrounding relationship to the adjacent portions of the upper and lower tubular body portions and defines an annular fluid pressure chamber within which an annular piston is reciprocable. Fluid pressure derived from pressurizing the bore of the tubing string is supplied to the annular fluid pressure chamber through a port system built into the top sub and a longitudinally extending pipe. Such application of fluid pressure first severs shear elements which are provided to hold the components of the packer in their run-in positions, and then effects an upward movement of the cylinder, thus compressing the compressible packing elements against an annular stop block or packing element retainer secured to the top portions of the upper tubular body portion. Concurrently, the downward motion of the annular piston effects a downward movement of an upper cone element and forces the slips downwardly toward engagement with the lower cone element and thus effects the radial expansion of the slips into biting engagement with the conduit wall. A conventional body lock ring is provided which is operative between the piston and cylinder to hold these elements in their expanded positions.
Thus, the packer may be set at any desired location within the well conduit and the mandrel bore is in fluid communication between the tubing string at its upper end and a lower tubing string or other connection to a submersible pump at its lower end. The electrical conduit for driving the pump is disposed in sealed relationship with respect to the eccentric passage provided for it in the top sub and thus does not in any manner permit fluid passage around the conduit to bypass the packing elements.
The aforedescribed packer may be conveniently unset and retrieved from the well by an upward movement of the tubing string, resulting in an upward movement of the top sub, and hence of the mandrel. Such upward movement effects the shearing of the shear ring provided between the top sub and the upper tubular body so that both the top sub and the mandrel may be shifted upwardly relative to the upper and lower tubular bodies. To reduce the size of the shear ring, a supplementary restraint is provided by a C-ring biased to a locking position by pistons responsive to any differential between tubing pressure and annulus pressure.
The upward movement of the bottom end of the mandrel effects an upward movement of the lower support block and moves it out of engagement with the locking heads of the collet which secures the lower cone to the lower tubular body portion, thus releasing the slips. Further upward movement of the mandrel will bring the lower support block into engagement with an internal shoulder on the lower tubular body and effect upward movement of the lower tubular body portion, the body connector sub and the upper tubular body portion. Such upward movement effects the release of compressive force on the elastomeric packing elements, permitting them to collapse to their unset positions and, of course, the upper and lower slip cones are removed from engagement with the slips, permitting release of the packer from the conduit wall. The lower slip cone is carried upwardly with the body portions of the packer by an inwardly projecting shoulder provided on the slip cage which is secured to the upper cone and extends downwardly in surrounding relationship to the lower cone. Thus, the entire packer assemblage is returned to its unset position and can be retrieved from the well.
Further advantages of the invention will be readily apparent to those skilled in the art from the following detailed description, taken in conjunction with the annexed sheets of drawings, on which is shown a preferred embodiment of the invention.
BRIEF DESCRIPTION OF DRAWINGS
FIGS. 1A, 1B, 1C, and 1D collectively constitute vertical sectional views of a packer embodying this invention, with the elements of the packer shown in their run-in positions. These figures are taken on the planes 1--1 of FIG. 4.
FIGS. 2A, 2B, 2C, 2D, 2E and 2F collectively constitute an enlarged scale vertical sectional view of the packer embodying this invention, with the elements thereof shown in their run-in position. These figures are taken on the planes 2--2 of FIG. 4.
FIG. 3 is an elarged scale sectional view taken on the plane 3--3 of FIG. 1C.
FIG. 4 is an enlarged scale sectional view taken on the plane 4--4 of FIG. 1B.
FIG. 5 is an enlarged scale sectional view taken on the plane 5--5 of FIG. 1D.
FIG. 6 is an enlarged scale sectional view taken on the plane 6--6 of FIG. 1D.
DESCRIPTION OF PREFERRED EMBODIMENT
Referring to the drawings, packer 1 embodying this invention comprises a threaded assemblage of a top sub 10, an upper tubular packer body portion 20, a connecting body portion 25, a lower tubular packer body portion 30, a lower support ring 40, and a hollow mandrel 50 connected intermediate the top sub 10 and the lower tubular support ring 40. Top sub 10 has a generally cylindrical exterior configuration and is traversed by two eccentric longitudinal passages 11 and 12. Passage 11 is sized to accommodate a mandrel having a bore equal to that of the tubing string TS to which the top sub is threadably attached as by threads 11a. Mandrel 50 is sealably secured in passage 11 by threads 11a and O-ring 11c. Thus, the bore of the hollow mandrel 50 is in communication with the bore of the tubing string TS.
The other eccentric longitudinal bore 12 in the top sub 10 is provided with internal threads 12a for mounting an electrical conduit guide tube 13. As shown only in FIG. 1A, the guide tube 13 extends upwardly and is radially enlarged at its upper portion and provided with threads 13a within which a conventional sealed coupling 14 is mounted for sealably mounting an electrical conduit 5 within the bore of guide tube 13. Conduit 5 extends throughout the entire length of the packer in generally parallel relationship to the mandrel 50 and passes through an eccentric hole 42 provided in the bottom support block or ring 40. Support ring 40 is further provided with an eccentric passage 41 for securement to the bottom end of the mandrel 50 in a manner to be hereinafter described.
The upper tubular body portion 20 is provided with external threads 20a adjacent its upper end which threadably mount an abutment sleeve 21. The top end of sleeve 21 is of reduced diameter and provided with external threads 21a which are secured to a coupling sleeve 22. Set screw 21b secures this threaded connection. Coupling sleeve 22 is detachably secured to the bottom end of the top sub 10 by two separate elements. The first element is an annular shear ring 23 which is mounted in a suitable groove in the outer periphery of the top sub 10 and engages a ring 23a which in turn engages an inwardly projecting shoulder 22b provided on the coupling sleeve 22 after limited upward movement of the top sub 10 relative to the upper tubular body portion 20. Additionally, the coupling sleeve 22 defines at its extreme upper end an inwardly projecting annular shoulder 22c which is engaged by a C-ring 24 which is urged outwardly by plurality of peripherally spaced locking pistons 24a (FIG. 4) having O-rings 24b. Pistons 24a are conventionally mounted in the top sub 10 and are biased outwardly to hold C-ring 24 in locking engagement with coupling sleeve 22 by fluid pressure derived from tubing string TS by ports 10n within the packer body portion 24a. Seal 22f prevents entry of well debris and the outer faces of the locking pistons 24a are exposed to annulus pressure. When fluid pressure within the tubing string exceeds the annulus pressure, the locking pistons 24a will urge C-ring 24 outwardly to its locked position. When such pressures are equalized, the locking pistons 24a will be shifted inwardly by the C-ring 24 and thus C-ring 24 contracts to an unlocking position. Hence, the top sub 10 cannot be disconnected from the upper tubular body if the pressure within the tubing string exceeds the annulus pressure. Pistons 24a and C-ring 24 are shown in their locked positions in FIGS. 1A and 2A.
Upper tubular packer body portion 20 is provided with external threads 20c adjacent its lower end and such threads are threadably engaged by the upper portion of the body connector sub 25. This threaded connection is sealed by an O-ring 20d. The lower end of the body connector sub 25 is provided with internal threads 25a and secured to the top end of the lower tubular body 30. This threaded connection is sealed by O-ring 25b. Thus the upper tubular body 20, the connecting body sub 25 and the lower tubular body 30 form a continuous tubular packer body around which all of the packing elements of the packer, including both slip elements and elastomeric sealing elements are mounted, together with a piston and cylinder apparatus for effecting the expansion of the slips and the sealing elements to set the packer.
The sealing elements 60 comprise a plurality of annular elastomeric members 62 which are respectively separated by conventional annular spacers 64. The upper end of the uppermost annular elastomeric element 62 abuts the lower end of the abutment sleeve or ring 21. A gage ring 21c is mounted on external threads 21d to the bottom of the abutment ring 21 to minimize extrusion of the elastomeric seal material around the abutment ring 21. The bottom face of the lowermost elastomeric sealing element 62 abuts the top face of a cylinder sleeve 70. Sleeve 70 is provided with external threads 70a at its upper end to mount a gage ring 72 thereon to minimize extrusion of the elastomeric seal material. The lower portion of the cylinder sleeve 70 defines an annular chamber 75 surrounding the tubular connecting body 25. Such chamber extends beyond the bottom end of the tubular connecting sub 25 to surround the top end of the lower body portion 30. In the chamber 75, an annular piston 80 is slidably and sealably mounted. An O-ring 70b seals the joint between the top of cylinder sleeve 70 and the lower portion of the upper tubular body 20. The lower end of the cylinder sleeve 70 is secured by a plurality of shear screws 74 which engage an annular groove 90a provided on the exterior of a connecting sub 90.
A sealable mounting of the piston 80 within the fluid pressure chamber 75 is accomplished by internal and external O-rings 80a and 80b respectively mounted in internal and external grooves formed in the upper end of the piston 80. The lower end of piston 80 is provided with wicker threads 82 which cooperate with a conventional body lock ring 84 which is mounted between the wicker threads 82 and internal rachet threads 76 formed on the lower interior portion of the cylinder sleeve 70.
During run-in, and in the absence of fluid pressure being supplied to the fluid pressure chamber 75, the cylinder sleeve 70 is latched to the connecting body portion 25 by an annular C-ring 78 which cooperates with an external recess 25d formed on the connecting body portion 25 and an internal recess 70d formed on the inner wall of the cylinder sleeve 70. So long as the C-ring 78 is in a contracted position, the cylinder sleeve 70 is locked to the tubular body assemblage of the packer. C-ring 78 is held in the contracted position by an annular extension 80e formed on the extreme upper portion of piston 80. Following initial movement of the piston 80 in a downward direction, the extension 80e rides off the locking C-ring 78 and permits the release of the cylinder sleeve 70 from the tubular body assemblage of the packer.
The connecting sub 90 is connected to the bottom of piston 80 by threads 90e and is provided with internal threads 90b by which it is secured to the top end of an upper cone 100. This threaded connection is secured by set screw 90c. Upper cone 100 is provided with an upwardly facing annular shoulder 101 to which is secured a slip cage mounting sleeve 102 having external threads 103 for threadably engaging the top portions of a conventional slip cage 105. Shear pins 104 hold the upper cone element 100 in its run-in position. Slip cage 105 is provided with a plurality of peripherally spaced slots 105a within which are conventionally mounted a plurality of slips 106. Compression springs 107 urge the slips radially inwardly. Slips 106 are provided with an upwardly facing inclined surface 106a which cooperates with a downwardly facing inclined surface 100a formed on the bottom of the upper slip 100 and a downwardly facing inclined surface 106b which cooperates with an upwardly facing surface 110a formed on the top portion of a lower cone 110. Thus, upward motion of lower cone 110 relative to upper cone 100 will produce a radial expansion of the slips 106 into biting engagement with the casing wall, in a manner well known in the art.
The lower extremity of bottom cone 110 is provided with external threads 111 to which is secured a lower cone locking sleeve 112. A set screw 113 secures the threaded connection. It should also be noted that the extreme bottom end of slip cage 105 is provided with an inwardly projecting shoulder 105e which engages a downwardly facing shoulder 110d on the lower cone 110 to effect the removal of the lower cone 105 when retrieval of the packer is desired.
The lower cone locking sleeve 112 is provided with a pair of internal annular recesses 112a. The extreme lower portions of the lower tubular body portion 30 is formed as a plurality of peripherally spaced collet arms 32 having enlarged locking head portions 32a formed on the bottom ends thereof. The locking head portions 32a are held in locking engagement with the recesses 112a by the lower cylindrical support 40. As best shown in FIG. 6, the lower cylindrical support 40 is of cylindrical configuration defining a large eccentric bore 41 to receive mandrel 50, and a smaller eccentric bore 42 to receive conduit 5. Bore 42 is receivable within an annular external recess formed on the bottom end of the mandrel 50. Cylindrical support 40 is formed in two pieces 40a and 40b which are interconnected by bolts 40c and thus clamped to mandrel 50.
From the description thus far, it is apparent that the mandrel 50 and the electrical conduit 5 are sealably secured within the tubular packer body assemblage. If the length of the packer dictates that additional lateral support be provided for the mandrel 50 and the electrical conduit 5, such support may be provided through the insertion of an upper cylindrical support member 46. Support member 46 (FIG. 3) has a large eccentric aperture 46a contoured to receive the exterior of the mandrel 50 and another connecting aperture 46b to receive the electrical conduit 5.
Upper support 46 is preferably mounted intermediate the bottom end of the upper tubular body 20 and an upwardly facing surface 25e formed on the connecting tubular body 25. As best shown in FIG. 2C, the upper support ring 46 provides a fluid passage 46c for directing tubing pressure to the interior of the fluid pressure chamber 75. Such fluid passage also comprises a radial port 25f in the wall of the tubular connecting housing 25 which is sealed off by a pair of O-rings 46f and 46g provided on the periphery of the support ring 46. An upwardly extending pipe 48 is threaded by threads 46e into upper support ring 46. Pipe 48 is provided with a plurality of radial apertures 48a which communicate with the radial port 46c through an annular recess 48d. O-rings 48b on the exterior of pipe 48 seal off the connection between ports 48a and 46c.
The upper end of fluid transmission pipe 48 is sealably mounted in a hole 10k opening in the bottom end of the top sub 10 by an O-ring 10m (FIG. 2B). The bore 48c of the fluid transmission pipe 48 is thus in fluid communication with a radial port 11b extending outwardly from the bore 11 of the top sub 10. Thus, tubing pressure may be supplied through the fluid transmission pipe 48, the radial port 48a, radial port 46c, radial port 25f and then into the fluid pressure chamber 75 to actuate the annular piston 80.
From the foregoing description, the operation of the packer with electrical conduit bypass will be readily apparent to those skilled in the art. The packer is run into the well to a desired position with the components thereof located in the positions shown in FIGS. 2A-2E. If the bore of the mandrel is not closed by an electric pump (not shown) which is suspended from the bottom end of the mandrel, then a conventional plug is set by wireline within the bottom end of the mandrel 50 or a tubing string depending therefrom. Thus, fluid pressure within the bore of the tubing string can be increased and such increased fluid pressure passes through the radial port 11b and into the bore 48c of the fluid transmission pipe 48. From the pipe 48, it passes into the fluid pressure chamber through the aligned ports 48a, 46c and 25f into the upper end of the fluid pressure chamber 75. Such fluid pressure acts on the top end of the piston 80 to move the piston downwardly slightly, thus releasing the C-ring latch 78 between the cylinder sleeve 70 and the connecting tubular body portion 25. Also, the shear screws 74 at the bottom end of the cylinder sleeve 70 will be sheared, thus leaving the cylinder sleeve 70 free to move upwardly to compress the elastomeric packing assemblage 60 while the piston 80 moves downwardly to effect the setting of the slips 106 by downward movement of the upper cone 100 relative to the lower cone 110. Hence the packer is set in the desired position in the subterranean well and the electrical conduit 5 bypasses the packer without in any manner interfering with the flow area for the tubing string which passes through the bore 11 of the top sub 10 and the bore 50a of the mandrel 50.
When it is desired to release the packer, the annulus pressure is equalized with the pressure within the packer body or vice versa so no pressure differential exists between the inside and the outside of the tool. This releases C-ring 24. An upward force is then applied to the tubing string TS which results in an upward force being transmitted to the top sub 10 to effect the shearing of shear ring 23, thus freeing the top sub 10 and the connected mandrel 50 for upward movement with the tubing string. Limited upward movement of the mandrel 50 effects the upward displacement of the lower support ring 40 to permit the locking collet heads 32a to move inwardly and release from the recessses 112a in the lower cone locking sleeve 12. This permits the lower cone 110 to release and, the continued upward movement of the top sub 10 and mandrel 50 brings the top face of the lower support ring 40 into engagement with the downwardly facing shoulder 30f (FIG. 2E) provided on the interior of the lower tubular body portion 30. The slip cage 105 is, of course, moved upwardly with the upper slip 106 and the inwardly projecting shoulder 105e on the bottom of the slip cage 105 engages a downwardly facing surface 110b formed on the lower slip 110 to effect the removal of the lower slip with the remainder of the packer elements.
If desired, more than one bypass passage for electrical conduit, control fluid pipes, etc. may be accommodated by the provision of additional eccentric apertures in top sub 10 and upper and lower support rings 46 and 40 to receive such additional bypass elements and appropriate seals for such additional bypass elements.
It should be noted that the provision of the piston biased C-ring 24 permits a substantial reduction in size of annular shear ring 23, since upward fluid pressure forces on the mandrel 50 and top sub 10 are absorbed by the piston biased C-ring 24.
Although the invention has been described in terms of specified embodiments which are set forth in detail, it should be understood that this is by illustration only and that the invention is not necessarily limited thereto, since alternative embodiments and operating techniques will become apparent to those skilled in the art in view of the disclosure. Accordingly, modifications are contemplated which can be made without departing from the spirit of the described invention. | A packer for a subterranean well conduit providing an electrical conduit bypass comprises a top sub having a first eccentric bore connectable between a tubing string and a mandrel and a second eccentric passage sealingly receiving an electrical conduit. A tubular body assembly is shearably connected to the top sub and mounts an annular packing element, an annular cylinder and piston unit and an annular slip and cone assemblage in axially stacked, abutting relationship. A support block secured to the lower end of the mandrel supports the electrical conduit and secures the lower cone against relative movement so that extension of said cylinder and piston effects setting of the packer. Upward movement of the top sub effects unsetting and retrieval of the packer. | 4 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application is related to U.S. Provisional Application 60/491,951 filed Aug. 1, 2003 and U.S. Provisional Application 60/491,952 filed Aug. 1, 2003.
BACKGROUND OF INVENTION
[0002] The present invention relates generally to tracking systems for tracking the location of valuable materials, persons, objects, and more particularly, but not limited, to the tracing of stolen articles, object or persons through existing cellular network infrastructure, global positioning system (GPS), and location algorithms using a combination of directional vectors and signal strength estimates based on Radio Frequency transmissions.
[0003] Many systems exist which make use of the constellation of Global Positioning satellites orbiting the earth. Such systems range from navigational aids to tracking devices. For example, there is a vehicle tracking and security system that allows immediate response in case of vehicle theft, an accident, vehicle breakdown, or other emergency. Guardian and tracking functions are provided through mobile units installed in hidden locations in vehicles to be monitored. The mobile units communicate with a control center. Preferably, the mobile unit provides vehicle theft and intrusion protection using an in-vehicle alarm and security system linked to the control center by a transceiver in the mobile unit. Also, a keypad or other human interface device is provided, allowing a vehicle driver or occupant to signal the control center that a particular type of assistance is needed. The vehicle's location may be automatically transmitted to the control center along with any automatic alarm signal or manually entered request, the location being precisely determinable anywhere in the world through use of Global Position System (GPS) information. The system provides continuous monitoring of a large number of vehicles for a broad range of status and emergency conditions over a virtually unlimited geographic area, also allowing manual communication of requests for assistance to that specific location.
[0004] Another example of the use of GPS to track the location of an automobile is an automatic vehicle location system that includes a radio positioning system receiver which receives GPS radio signals and includes a two-gimbaled gyroscope, which is used by a dead-reckoning positioning system. A controller determines position based upon the radio positioning system when the radio signals are available and upon dead-reckoning when the radio signals are not available. The dead-reckoning process is based upon a compensation factor, which is established in response to data received from the radio positioning system. The compensation factor acts as an adjustment to an inner gimbal angle to compensate for a minor drift away from level by the inner gimbal.
[0005] A further example might be a method for detecting the position of a moving body in which the position of a moving body such as a vehicle can be detected with a high degree of precision. It is possible to perform at least data communication using radio waves between radio base stations and a vehicle capable of movement. Precise positions are stored in advance in the radio base stations and radio wave clocks that keep a common time are provided in the radio base stations. The radio base stations transmit radio waves containing this time information. The vehicle receives these radio waves and determines the difference between the received time information a clock provided in the vehicle in order to detect the current position of the vehicle by calculating the distances between the vehicle and each of the radio base stations. Furthermore, it is also possible for the position of the mobile station to be calculated using a combination of information from the fixed station and information from GPS satellites. By employing this type of structure, it is possible to calculate the position of the mobile station even when it is not possible to calculate the position of the mobile station using the fixed stations alone or GPS satellite alone. Therefore, it is possible to find the position of the mobile station more accurately than when a conventional method is used.
[0006] There also exists a tracking device configured to resemble a stack of currency and represents a system for use in catching thieves. The device relates to the electronic tracking of cash stolen from a bank or other institution via an electronic signaling device placed within a stack of currency that transmits location information to the authorities as the cash is moved from location to location. The tracking device allows law enforcement officers to electronically monitor money stolen from a bank. The tracking device is sized to fit within a stack of currency in a teller's drawer or a bank's vault. When the tracking device is activated, it transmits a beacon signal that continuously runs for the duration of the battery. Thus, the tracking device would automatically send a signal to either a fixed monitoring station, such as a local police station, or to a mobile monitoring station, such as a helicopter or police car, allowing for continual tracking of the thief in possession of the stolen money. By knowing the location of the money, the police can track and apprehend the perpetrators. It is designed to be a circuit card smaller than a dollar bill and thin enough to be concealed between two (2) bills, thereby allowing it to be placed into a stack of money undetected. Further, the device can be waterproofed and made flexible, which will have no effect on its ability to be continually tracked, but would prevent someone from shorting out the device in liquid. Alternative embodiments allow variations of the tracking device to be placed within other objects of value. An alternative embodiment allows the tracking device to be automatically activated when it is taken past a certain point (electronic fence) from where it is stored.
[0007] Furthermore, there are tracking systems for tracking the location of stolen articles, and more particularly, to disguised currency bundles for aiding law enforcement officials in apprehending thieves and recovering stolen monies. The system includes a security pack for assisting in the recovery of stolen monies which includes a housing disguised as a bundle of currency bills, but containing a GPS receiver for receiving GPS signals from overhead satellites combined with a cellular phone transmitter (Module), a microprocessor, antennae, and a battery. Following a bank robbery, the microprocessor activates the cellular phone transmitter to dial the telephone number of a central monitoring station. The microprocessor obtains location data from the GPS receiver and transmits the location data, along with identification information, to the central monitoring station. The security pack may also include a separate, conventional RF beacon transmitter for allowing authorities to home-in on the security pack within a large building or other structure, either after the GPS signals are lost, or after the location of the security pack is localized to a specific area, building or individual.
[0008] All of the devices described above are implemented, or require for implementation, access to GPS or a custom radio network of receivers. This is an expensive requirement, increasing overall costs and the size of the devices. There is thus a need for a smaller, less expensive solution to tracking and aiding law enforcement officials in the recovery of lost or stolen articles or missing children while utilizing existing cellular telephone network infrastructure.
SUMMARY OF INVENTION
[0009] In view of the aforementioned needs, there is contemplated a system, method and device capable of being implemented using existing communications infrastructure to locate a missing, stolen, or lost item or person.
[0010] In accordance with the subject invention, there is provided a method for locating an asset. The method includes the step of linking at least one portable transmitter system with a selected asset. A cellular communication is then initiated from the at least one portable transmission system to an associated device controller. Primary location information representing the cellular area from which the cellular communication is made is then communicated to the device controller. A secondary location system is then initiated in accordance with the location information. The secondary location information, from the portable transmission system, is then broadcast and received into a tracking system.
[0011] In a preferred embodiment, the method for locating an asset includes comparing the primary location information with data of a geographic database in order to isolate the geographic area of interest. Map information is then generated relating to the primary location information. The method then initiates receipt of the secondary location information in accordance with the geographic area of interest. In another embodiment, the method for locating an asset includes the step of generating the secondary location information in accordance with satellite data obtained from an associated global positioning system. In an alternate embodiment, the method for locating an asset includes the step of determining, in the tracking system, a location of the selected asset in accordance with data generated as a function of the strength of a signal associated with the secondary location information received therein. In an alternate embodiment, the method for locating an asset includes the steps of simultaneously monitoring a plurality of portable transmission system communications, and generating fee data representative of each of a plurality of monitored portable data transmissions. The primary and secondary location information are then transmitted to a law enforcement authority in order to track the asset that is determined to be stolen.
[0012] Further, in accordance with the present invention, there is provided a system for locating an asset. The system includes means adapted for linking at least one portable transmitter system with a selected asset. The system also includes means adapted for initiating a cellular communication from the portable transmission system to an associated device controller. The system further includes means adapted for communicating to the device controller primary location information representative of a cellular area from which the cellular communication is made. The system also comprises means adapted for initiating a secondary location system in accordance with the location information and means adapted for broadcasting secondary location information from the portable transmission system. The system further comprises means adapted for receiving secondary location information into a tracking system.
[0013] In a preferred embodiment, the system for locating an asset also includes means adapted for comparing the primary location information with data of a geographic database in order to isolate a geographic area of interest, means adapted for generating map information relating to the primary location information, and means adapted for initiating receipt of the secondary location information in accordance with the geographic area of interest. In another embodiment, the system for locating an asset further includes means adapted for generating the secondary location information in accordance with satellite data obtained from an associated global positioning system. In an alternate embodiment, the system for locating an asset also includes means adapted for determining, in the tracking system, a location of the selected asset in accordance with data generated as a function of a strength of a signal associated with the secondary location information received therein. In a preferred embodiment, the system o for locating an asset further comprises means adapted for simultaneously monitoring a plurality of portable transmission system communications, and means adapted for generating fee data representing each of a plurality of monitored portable data transmissions. Means adapted for selectively communicating are then used to communicate either the primary or the secondary location information to law enforcement authorities in order to track the asset.
[0014] The subject invention is directed to a tracking system that is capable of locating and recovering a person or valued article. The system comprises a tracking device (hereinafter “Device” or “Unit”), the existing cellular-telephone network infrastructure (hereinafter, “Air-link”), tracking, database, analysis and display software (hereinafter, “Device Controller”), and vehicle-mobile (hereinafter “Trackers”) direction-finding transceivers and man-portable (hereinafter “Hand-Held Trackers”) direction-finding receivers.
[0015] In accordance with the subject invention, the Device comprises a wireless cellular-data modem, a beacon transmitter, supervisory control logic means, antennae, a portable power-supply, a user interface, and an application specific enclosure.
[0016] In one aspect of the subject invention, the Device Controller comprises a computer readable medium of instruction for receiving status data from a fielded Device, sending command data to the fielded Device, providing database registration/deregistration for the Device entering or leaving service, providing event logging for the Device in service, providing a graphical tactical display that locates all active Devices and Trackers and Hand-Held Trackers. The Device Controller suitably shares the tracking data it has collected from all Trackers and Hand-Held Trackers, thereby providing each fielded Tracker and Hand-Held Tracker with full access to view the tactical display of a developing track. Furthermore, the Device Controller is capable of acting as a central repository for tracking event data, as well as for system administrative functions.
[0017] In another aspect of the subject invention, there is a Tracker comprising a vehicle-portable direction-finding (“DF”) receiver capable of homing in on a beacon signal generated by a Device. The Tracker is equipped so that it is network aware, as well as position aware. The Tracker shall be capable of relaying its own position and the absolute bearing angle and/or proximity to the beacon transmitter, i.e., the Device, back to the Device Controller using the Air-link. The Tracker is further equipped with means to receive, from the Device Controller, tracking data the Device Controller receives from other Trackers and HandHeld Trackers, wherein the user of the Tracker is provided with access to the full tactical view of a developing track. In essence, the Tracker is capable of working in concert with other fielded Trackers and Hand-Held Trackers, thereby coordinating activities in a “wolf-pack” fashion. In an alternate embodiment, the Tracker may also be equipped with a global positioning system to provide fine-position resolution.
[0018] In one aspect of the subject invention, there is a HandHeld Tracker, i.e., a hand-held tracking receiver, to be utilized in environments that do not permit vehicle access; i.e., within buildings, shopping centers, etc. These devices shall also be network- and position-aware; then shall optionally include fine-position resolution capability using the global positioning system (GPS). Each tracking receiver shall be capable of relaying its own position and the absolute bearing angle and/or proximity to the beacon transmitter back to the Device Controller via the Air-link. The Hand-Held Tracker is further equipped with a display and user interface, a cellular modem, a microcontroller, and a direction finding receiver. In an alternate embodiment of the Hand-Held Tracker, there is provided a heading sensor compass and a GPS receiver.
[0019] In another aspect of the subject invention, there is a method for using the existing cellular-telephone network infrastructure to supply geographic location data of a cellular site that is currently servicing the Device.
[0020] Still other aspects of the present invention will become readily apparent to those skilled in this art from the following description wherein there is shown and described a preferred embodiment of this invention, simply by way of illustration of one of the best modes suited for to carry out the invention. As it will be realized, the invention is capable of other different embodiments and its several details are capable of modifications in various obvious aspects all without departing from the invention. Accordingly, the drawing and descriptions will be regarded as illustrative in nature and not as restrictive.
BRIEF DESCRIPTION OF DRAWINGS
[0021] The accompanying drawings incorporated in and forming a part of the specification, illustrates several aspects of the present invention, and together with the description serve to explain the principles of the invention. In the drawings:
[0022] FIG. 1 is an example of a block diagram of a Device;
[0023] FIG. 2 is an example of a block diagram of a Tracking Receiver;
[0024] FIG. 3 is an example of a system implementing the subject invention; and
[0025] FIG. 4 is an illustration of a flow chart of a method in accordance with one aspect of the present invention.
DETAILED DESCRIPTION
[0026] Throughout this description, the preferred embodiment and examples shown should be considered as exemplars, rather than limitations, of the present invention.
[0027] Referring first to FIG. 1 there is illustrated a block diagram of Device 100 . The Device 100 comprises a trigger switch 102 operatively coupled to a microcontroller 104 . It will be appreciated by one of skill in the art that the trigger switch is suitably constituted by a plurality of different mechanisms and electromechanical means. For example, the trigger switch 102 is advantageously a reed switch, a motion detector, a clock, and a counter, internally or externally activated. An energy source 110 is suitably constituted by internal or external means, e.g., rechargeable batteries, alkaline batteries, photovoltaic cells, fuel cells, lithium-ion, nickel-cadmium, or nickel-metal hydride, and provides electric power to the various other components of the Device 100 .
[0028] The Device 100 further incorporates a beacon transmitter 106 , and a cellular data modem 108 , which is capable of including a global positioning system transceiver. The beacon transmitter and its attached antenna 112 , is communicatively coupled to the microcontroller 104 and receives power from the energy source 110 . Similarly, the cellular data modem/global positioning system transceiver 108 , and its respective antennae 114 and 116 , also are communicatively coupled to the microcontroller 104 and draw power from the energy source 110 . One of appreciable skill in the art will take notice that the type of power source is dependent upon the application for which the Device 100 is being utilized. Thus, the capacity of the energy source 110 is of a size determined by compatibility with the Device's 100 specific application, deployment environment, and operational endurance requirements. For example, in the case of application to persons, the endurance of the Device 100 will be noticeably longer than the application of the Device 100 to a valuable article, e.g., a ream of bank notes.
[0029] The microcontroller 104 implements supervisory logic control over the Device 100 . The microcontroller 104 is responsible for controlling and operating the beacon transmitter 106 , controlling the cellular data modem 108 , receiving input from the trigger switch 102 and regulating the energy source 110 . The microcontroller-logic section, exemplified in FIG. 1 as the microcontroller 104 , is responsible for coordinating communications over the Air-link, monitoring the Device's 100 user-interface (if any), and managing resources used by the Device 100 . Firmware residing on the microcontroller 104 provides for transfer of small data payloads to and from the Device 100 . One of ordinary skill in the art will appreciate that such a transfer is suitably implemented using standard text-messaging protocols currently in widespread use. The firmware residing on the microcontroller 104 is equipped to accept operating-mode commands including adjustment parameters. This allows the operations of the Device 100 to be dynamically and finely tailored to a given tracking situation by making transmission rates, cell-modem 108 reporting intervals, message recipients, etc., remotely adjustable. It will also be understood by those skilled in the art that the microcontroller 104 suitably comprises ports (not shown) for a variety of sensors, microphones, IP cameras, and the like. The addition of various ports to the microcontroller 104 enables a broader range of data to be collected by the Device 100 . The cellular-data modem 108 is advantageously a purchased modular sub-assembly, or for volume applications may be based upon a fully integrated chip-level design. Operatively coupled to the cellular modem 108 is the cellular modem antenna 114 . It will be appreciated that antenna 114 and 116 are capable of being mounted either internally or externally, dependent upon the application for which the Device 100 is correspondingly implemented. That is, the antenna 114 is able to be visible externally, for instance in the case of a child's shoe, belt-buckle or the like, or operatively integrated with the enclosure of the Device 100 , for use with bank notes, works of art, or other valuable articles. As one of skill in the art will notice, protocols used by the cellular modem 108 will depend upon the application of the Device 100 , the location of the device, and the actual modem implemented. Protocols used by the cellular-data modem 108 include, but are not be limited to TDMA, CDMA, GSM, IP, TCIP, or the like. The choice of cellular-telephone protocol will be dictated by the Device's 100 specific application and deployment environment.
[0030] The beacon transmitter 106 is any radio-frequency (RF) transmitter known in the art or becoming available in the art. For purposes of example only, a suitable variable frequency transmitter of 160 MHz to 460 MHz is used. An example of such a transmitter is the ETS product manufactured and distributed by Spectrum Management, LLC. One system employs a proprietary array of antennas distributed around an area of interest. This array allows for coarse tracking of a transmitter disposed within an area covered by the proprietary array. Information obtained from this coarse tracking allowed for positioning of secondary tracking devices so as to more precisely track a location of the transmitter. Such system, while fully functional, requires the added expense of installing and maintaining the proprietary transceiver network. As such, certain areas, such as rural locations, would often lack the necessary commercial activity or infrastructure to allow for operation.
[0031] The beacon transmitter 106 envisioned in the preferred model of the Device 100 is an amplitude-shift-keyed (ASK) very-high-frequency (VHF) RF transmitter circuit that outputs 100 mW of RF energy into a 50 Ohms load. The beacon transmitter 106 is controlled and operated by supervisory logic control means implemented in the microcontroller 104 . The beacon transmitter 106 is operatively and communicatively coupled to the beacon transmitter antenna 112 . In one embodiment, the antenna 112 is integrated into the Device 100 enclosure. The skilled artisan will appreciate that the antenna 112 is capable of being externally mounted, depending upon the application for which the Device 100 is currently being implemented. It will be noted that each beacon transmitter 106 used in implementing the subject invention uses a unique identification code. Such code is suitably differentiated by software integral to the beacon transmitter 106 or by code residing in the microcontroller 104 .
[0032] The Device 100 is capable of implementation in a variety of forms, depending upon the application for which the Device 100 is utilized. For example, and not intending to limit the protection for which the subject invention is legally and equitable entitled, there are planar embodiments, formed cavity embodiments, modular or integrated embodiments, embodiments utilizing camouflaged means, etc. An example would be a flat, planar embodiment capable of insertion without noticeable deformation, into a stack of bank notes. There is also insertion into the sole of a shoe or belt enabling location of a missing person. Further enclosure embodiments are advantageously customized to represent the desired object for affixation of the Device 100 .
[0033] Turning now to FIG. 2 there is provided a block diagram exemplifying the subject invention's tracking receiver 200 receiving components, or the internal components of the Tracker and Hand-Held Tracker. As will be appreciated by one of skill in the art, the enclosures for the Tracker and the Hand-Held Tracker are capable of taking any number of formats, from a laptop computer, a Personal Data Assistant (PDA), a cellular telephone, a desktop computer, or the like. Of importance, as observable to the skilled artisan, is the inclusion of the components outlined in FIG. 2 . For purposes of explanation of FIG. 2 , the term “tracking receiver 200 ” is used to reference the Tracker and the Hand-Held Tracker.
[0034] The tracking receiver 200 of FIG. 2 , includes a microcontroller 204 suitably adapted to control a variety of integrated components and external devices. It will be appreciated by those skilled in the art that microcontroller 204 is suitably implemented by the microprocessor of a typical laptop, desktop or PDA. Operatively coupled to the microcontroller 204 of the tracking receiver 200 is a direction-finding (DF) receiver 202 , with three attached antennae 218 , 220 and 222 . As contemplated by the present invention, the three antennae 218 , 220 and 222 apportioned to the DF receiver 202 , as will be apparent to one skilled in the art, enables the DF receiver 202 to triangulate the signal broadcast by the beacon transmitter 106 of the Device 100 . The DF receiver 202 is communicatively coupled to the microcontroller 204 . The microcontroller 204 then implements supervisory logic means stored thereon to facilitate the translation of inputs received via the DF receiver 202 onto an integrated user interface and display 206 . The microcontroller 204 advantageously varies from a microprocessor residing on a laptop computer, PDA or other mobile computing device.
[0035] The microcontroller 204 is operatively coupled to an optional GPS receiver 212 and an optional heading sensor/compass 208 . The optional equipment provides greater range and mobility to the tracking receiver 200 than the DF receiver 202 alone. The tracking receiver 200 further includes a cellular data modem 210 and a cellular modem antenna 216 in operative connection with the microcontroller 204 . The GPS receiver 212 and the heading sensor (compass) 208 are optionally depicted in FIG. 2 and do not form part of the preferred embodiment.
[0036] The display and user interface 206 are any display and/or user interface known in the art, ranging from an LCD, TFT, or other visual means for displaying the output from the microcontroller 204 enabling an operator to view a location of the Device 100 . A standard QWERTY keyboard, touchpad, directional pad, stylus or other input means are used to implement the user interface as depicted as the display and user interface 206 of FIG. 2 . The cellular-data modem 210 of the tracking receiver of FIG. 2 receives information from the Device Controller via the existing cellular telephone network infrastructure. Operatively coupled to the modem 210 is a cellular antenna 216 , which is alternatively integrated into the tracking receiver enclosure or extending externally therefrom. Communications between the Device Controller and the tracking receiver are transmitted from the modem 210 to the microcontroller 204 . Such communication allows the tracking receiver to function remotely from the Device Controller and allows the operator to participate in the tracking of the Device 100 .
[0037] In an alternate embodiment, the GPS receiver 212 , the GPS antenna 214 and the heading sensor (compass) 208 are also depicted in FIG. 2 . The inclusion of these two components into the tracking receiver allows the Device Controller to monitor and plot the location of all tracking receivers currently being fielded in the search for Device 100 . The implementation of the GPS receiver 212 need not be integral to the tracking receiver. GPS modules are capable of subsequent attachment via any means known to one of ordinary skill in the art.
[0038] Furthermore, depending upon the configuration of the tracking receiver, the power supply (not shown) for the tracking receiver will vary. Such power sources include, but need not be limited to, photovoltaic cells, rechargeable batteries, alkaline batteries, generator means, or, in the case of the vehicle mounted embodiment, directly to the 12-volt system operating the internal combustion engine of the vehicle.
[0039] As used in FIG. 3 , the Device 100 is implemented, in the form of the planar embodiment, for use with tracking a stack of bank notes stolen during a robbery, and for purposes of explanation, the planar embodiment is represented as Device Transmitter 302 . It should be appreciated that the following example is easily relatable to another valuable article equipped with the Device 100 or even a missing child on which the Device 100 has been affixed onto an article of clothing. It should also be understood by those skilled in the art that the use of a single Device 100 is for exemplification only. The subject invention is equally capable of employing multiple Devices for use in a single stack of currency, layered between or attached to different bills in the stack. The skilled artisan will appreciate that multiple Devices in the stack of currency suitably enables continual tracking should one or more Devices loose power, be discovered, or be destroyed.
[0040] Returning to FIG. 3 , there is shown a Device Controller 306 communicatively coupled to cellular towers 310 , 312 , and 314 , as well as in communication with the Security Agency 315 . The Device Controller 306 , as explained above, operates to coordinate efforts of tracking the Device Transmitter 302 as it is moved from location to location. As the stack of bank notes (not shown) in which a Device Transmitter 302 is hidden, are removed from the bank drawer in which they had previously been stored, the magnet (not shown) which had kept the trigger 102 , e.g. inverse reed switch, opened is removed, thereby allowing the circuit to close. This then activates the microcontroller 104 by supplying power from the energy source 110 . The microcontroller 104 uses the cellular modem 108 to connect to the existing cellular telephone infrastructure, represented by towers 310 , 312 , and 314 . Concurrently with this activation of the cellular modem 108 , the microcontroller 104 also instructs the beacon transmitter 106 to begin RF broadcast.
[0041] As the bank notes in which the Device Transmitter 302 is hidden, are brought into the coverage area of the cell tower 310 , a specific 60 degree Sector 310 A of the 360 degree coverage area around the Cell Site is identified for direction purposes when the broadcast signal is picked up and the Device Controller 306 receives the signal. The Device Controller 306 processes the signal, noting that the cell tower 310 is the originating tower. The Device Controller 306 then determines the location of the cell tower 310 and the 60 degree Sector 310 A direction (the Sector indicated direction) and plots its location on a tactical map for uploading to the Trackers 307 , 308 , 309 and the Hand-Held Tracker 304 (HHT). The Trackers 307 , 308 , 309 and the HHT 304 are then directed by the Device Controller 306 to the specific Sector 310 A coverage area of the cell tower 310 . The 360 degree coverage area around any given cellular tower is divided into six (6) 60 degree Sectors, represented in FIG. 3 as 310 A, 312 A, 314 A, the size of the coverage area varies, but a typical coverage area ranges from a diameter of one mile to upwards of ten miles. It will be appreciated by one skilled in the art that the subject invention need not be limited to 60 degree Sectors. For example, the subject invention is equally capable of implementing three (3) 120 degree Sectors, or various other arcs of coverage, as dictated by the circumstances surrounding implementation of the subject invention.
[0042] While shown as a PDA, it will be appreciated that the HHT 304 is capable of implementation as any other portable communications device known in the art, provided the components, as presented herein, are included. Furthermore, the Device Controller 306 is depicted as a stationary personal computer, however one of ordinary skill in the art will appreciate that another computer processing device is capable of being advantageously employed in the subject invention.
[0043] The Device Controller 306 is a software application that runs on a standard PC, or alternatively is run as a process on a multi-tasking server-computer at the Security Agency (not shown) location. The Device Controller's 306 function is similar to that of Area-Wide-Monitor (AWM) software, which in essence provides for coarse tracking through a proprietary array of antennae distributed around an area of interest. The AWM monitors these antennae using customized software to obtain information allowing for the positioning of secondary tracking devices. The Device Controller 306 receives status data from the fielded trackers 304 , 307 , 308 and 309 , provides database registration/deregistration for the Device 100 entering or leaving the service area, provides event logging for all Devices in service, and provides a graphical representation of locations of both Devices and active tracking receivers.
[0044] As the Trackers 307 , 308 , 309 and the HHT 304 are vectored in to the general vicinity of Device Transmitter 302 , the bank notes in which the Device Transmitter 302 is hidden enter the coverage area of cellular tower 312 . Typical procedure for cellular architecture is to allow the cell tower 312 to pick up transmission and the cell tower 310 to drop transmission. The present invention, however, uses the relative known locations of cell towers 310 and 312 , allowing the Device Controller 306 to narrow the location of the Device Transmitter 302 to a much smaller area. The art of triangulation is well known in the art and need not be re-presented for purposes of this example. The narrowed location is then transmitted from the Device Controller 306 to the Trackers 307 , 308 , 309 and the HHT 304 via the cellular modems 210 . At this point in the tracking process all vehicles in the law enforcement fleet equipped with vehicle data terminals 313 , 317 , 318 , 319 and 320 become part of the tracking process.
[0045] Having thus been directed towards the Device Transmitter 302 , the Trackers 307 , 308 , 309 and the HHT 304 are now in range of the beacon transmitter 106 . As the four trackers 304 , 307 , 308 , 309 approach the Device Transmitter 302 , the DF receivers 202 (located on each tracker) triangulate the signal being broadcast by the Device Transmitter 302 , i.e., the Device 100 , located in the stolen bank notes. The microcontrollers 204 of the trackers 304 , 307 , 308 , 309 process the triangulated signals received by the DF receivers 202 and present the operators with graphical information via the display and user interfaces 206 . Updated information received via the cellular towers 310 and 312 is continually transmitted to the Device Controller 306 , as well as updated information from the trackers 304 , 307 , 308 , 309 . This allows the Device Controller 306 to monitor and direct the trackers 304 , 307 , 308 , 309 ever closer to the Device Transmitter 302 .
[0046] In an alternate embodiment, using the above example and FIG. 3 , there is shown one satellite representative of the constellation of global positioning satellites 316 . In this embodiment, the trackers 304 , 307 , 308 , 309 are equipped with GPS receivers 212 . This embodiment enables a service provider to use the trackers 304 , 307 , 308 , 309 to track the Device 100 , and then notify authorities to move in. Such positioning would be extremely helpful in the hands of Federal Bureau of Investigation agents pursuing a kidnapper. The agents in the field could give definitive positions, in the form of longitude and latitude coordinates to other agents, closing in on the kidnapped victim.
[0047] It should be noticed that the ability to transmit position data from a tracker to the Device Controller 306 using existing cellular infrastructure has a myriad of potential applications. The Device Controller 306 is able to record and report last known positions of the Device 100 , the Trackers 307 , 308 , 309 and the HHT 304 . Such reports are used by law enforcement or search and rescue authorities for both the apprehension of criminals and for the rescue of stranded hikers. The use of the existing cellular infrastructure further allows the Device Controller 306 to transfer small data payloads to and from the Device Transmitter 302 , implemented by using standard text-messaging protocols still in use. For example, a child's shoe equipped with the device notifies the child or responsible adult of an emergency. The most appropriate format would be latitude and longitude coordinates of the site and should include a mean radius of the cell site's Sector coverage area. Data transfer protocols should be standardized across all network providers. The data interface between the existing cellular telephone network and the Device Controller 306 could take several forms, including, but not limited to, Internet connectivity via an Internet Service Provider, dial-in access, or direct access via a cellular modem at the display console.
[0048] Referring now to FIG. 4 , there is shown a flow chart depicting the operation of the system of the subject invention. The operation of the system requires a number of operations to be performed to allow the location of the Device 100 to be used by the Trackers 304 , 307 , 308 , 309 . Beginning at step 402 , the cellular modem 108 of the Device 100 is activated and registered with the cellular network. It will be understood, with respect to the subject invention discussed above, that the triggering event, i.e., the event causing the activation, is any movement or other means of activating the Device 100 . The method progresses to step 404 where a determination is made whether the cellular network has failed to recognize the cellular modem. If the cellular modem is not recognized by the cellular network, the method then returns to step 402 and the cellular modem again attempts to register with the existing cellular network. If the Device 100 has successfully registered with the cellular network at step 404 , the method proceeds to capture the cellular location information from the Device 100 at step 406 .
[0049] After capture of the location information, the system will proceed to step 408 , where the location information is transmitted to the service provider at the Local Database or Internet Service Provider in step 408 . The Local Database, depending upon the type of services being provided, or alternatively, the Internet Service Provider, forwards the information along to the Device Controller 306 in step 410 , or provides the location of the Device 100 to the owner as part of the services provided thereto. In the event that the information is passed on to the Device Controller 306 in accordance with step 410 , the Device Controller 306 at step 414 receives the information and processes the cellular/Sector data and the corresponding vehicle tracker data to establish the speed and direction of the Device 100 .
[0050] At step 415 , the Security Agency 315 receives the information and displays the location on a local map screen. It will be understood by those skilled in the art that the Security Agency 315 is any governmental or security organization capable of locating and/or apprehending the Device 100 . It will be further appreciated by one of ordinary skill in the art that any other suitable display will be satisfactory to accomplish the forgoing.
[0051] The Security Agency is then able to forward the tracking information to its police units in the field at step 416 . This equates to the Security Agency, using the information garnered from the existing cellular network, to vector its units towards the Device 100 . Once in the general area, as directed by the Security Agency in step 416 , the fielded units use a vehicle mounted tracker or a Hand-Held Tracker to close in on the Device 100 .
[0052] Alternatively, as shown in FIG. 4 , when the cellular network is not available, the Device 100 activates a Radio-Frequency (RF) transmitter at step 407 . At step 409 , the Device Controller 306 receives the RF transmission and becomes aware of the activation. The Device Controller 306 then notifies tracking vehicles of the activation at step 411 . Beginning at step 412 , the tracking vehicles receive the RF transmission from the Device 100 . The tracking vehicles then send their corresponding location, direction, signal strength and direction from which the RF transmission is being received to the Device Controller 306 at step 413 . The system then returns to step 414 , where the Device Controller 306 processes the incoming information in order to accurately determine the location, speed and direction of the Device 100 . The system continues to operate as set forth above.
[0053] The embodiments above allow for a non-governmental entity, in the form of a service provider, to provide security for a customer. That is, the service provider is able to provide a customer with the whereabouts of the customer's tagged objects at any time. In the event the tagged object has been purloined, the service provider is even able to direct the police to the location of the missing object, using nothing more than the existing cellular telephone network infrastructure.
[0054] The invention extends to computer programs in the form of source code, object code, code intermediate sources and object code (such as in a partially compiled form), or in any other form suitable for use in the implementation of the invention. Computer programs are suitably standalone applications, software components, scripts or plug-ins to other applications. Computer programs embedding the invention are advantageously embodied on a carrier, being any entity or device capable of carrying the computer program: for example, a storage medium such as ROM or RAM, optical recording media such as CD-ROM or magnetic recording media such as floppy discs. The carrier is any transmissible carrier such as an electrical or optical signal conveyed by electrical or optical cable, or by radio or other means. Computer programs are suitably downloaded across the Internet from a server. Computer programs are also capable of being embedded in an integrated circuit. Any and all such embodiments containing code that will cause a computer to perform substantially the invention principles as described, will fall within the scope of the invention.
[0055] The foregoing description of a preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiment was chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled. | The present invention is directed to a method of asset location. The method includes the step of linking at least one portable transmitter system with a selected asset. A cellular communication is then initiated from the at least one portable transmission system to an associated device controller. Primary location information representing the cellular area from which the cellular communication is made is then communicated to the device controller. A secondary location system is then initiated in accordance with the location information. The secondary location information, from the portable transmission system, is then broadcast and received into a tracking system. The method of asset location includes the steps of simultaneously monitoring a plurality of portable transmission system communications, and generating fee data representing each of a plurality of monitored portable data transmissions. The primary and secondary location information are then transmitted to a law enforcement authority in order to track the asset that is determined to be stolen | 6 |
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